55 results on '"Kelvin H. Wan"'
Search Results
2. Management of cytomegalovirus corneal endotheliitis
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Angela H. Y. Wong, Wee Nie Kua, Alvin L. Young, and Kelvin H. Wan
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Cytomegalovirus ,CMV ,Endotheliitis ,Keratoplasty ,Corneal transplant ,Cornea ,Ophthalmology ,RE1-994 - Abstract
Abstract Background Cytomegalovirus (CMV) can manifest as corneal endotheliitis in immunocompetent individuals. Early diagnosis is prudent to prevent endothelial cell loss, which could ultimately lead to corneal decompensation. CMV DNA was first detected in an eye with corneal endotheliitis in 2006; since then, clinical evidence from numerous case reports and case series have accumulated. Main text In this narrative review, we identified several drugs, including ganciclovir, valganciclovir, and their combination in oral, intravenous, intravitreal, and topical forms in different concentrations, together with the judicious use of topical steroids, have reported variable success. There has yet to be any prospective comparative study evaluating the efficacy and safety of these assorted forms of treatment; clinical evidence is based on case reports and case series. CMV endotheliitis presenting with corneal edema can masquerade as other corneal diseases and thus poses a great challenge especially in post-keratoplasty eyes. Heightened awareness is needed before and after keratoplasty to start prompt prophylaxis and treatment. Conclusion There is no consensus on the management of CMV endotheliitis. Further studies are much needed to elucidate the optimal treatment modality, regime, and duration in the treatment and prophylaxis of CMV endotheliitis.
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- 2021
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3. Optical coherence tomography angiography in glaucoma: a mini-review [version 1; referees: 2 approved]
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Kelvin H. Wan and Christopher K.S. Leung
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Glaucoma ,Retinal, Vitreous & Macular Disorders ,Medicine ,Science - Abstract
The advent of optical coherence tomography angiography (OCT-A) provides a new opportunity to visualize the retinal vasculature in a non-invasive and dye-free manner which may help identify vascular abnormalities in glaucoma. While a reduction in retinal and optic nerve head vessel densities and blood flow indexes measured by OCT-A has been demonstrated in patients with glaucoma in many studies, it is unclear whether OCT-A provides additional information for the detection and monitoring of glaucoma compared with OCT measurements such as retinal nerve fiber layer thickness, neuroretinal rim width, and ganglion cell inner plexiform layer thickness. Longitudinal studies are needed to elucidate whether vascular abnormalities detected by OCT-A are a cause or a consequence of optic nerve damage in glaucoma.
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- 2017
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4. Toric intraocular lenses for astigmatism correction after keratoplasty in phakic and pseudophakic eyes
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Kelvin H, Wan, John S M, Chang, and Vishal, Jhanji
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Corneal Transplantation ,Lenses, Intraocular ,Phakic Intraocular Lenses ,Ophthalmology ,Lens Implantation, Intraocular ,Quality of Life ,Astigmatism ,Humans ,Surgery ,Refraction, Ocular ,Sensory Systems ,Anisometropia - Abstract
Residual astigmatism and anisometropia significantly affect patients' vision and quality of life even in clear grafts after corneal transplant. This study reviewed and summarized the role of toric intraocular lenses (IOLs) in phakic and pseudophakic eyes after penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty in correcting residual astigmatism. 342 eyes from 20 studies with iris-clipped toric IOL, ciliary sulcus toric implantable collamer lens, piggyback sulcus toric IOL, or posterior chamber toric IOL implantations for phakic, pseudophakic, or eyes undergoing cataract surgery after keratoplasty were included. Visual, refractive, and predictability outcomes were encouraging. Secondary realignment rate and complications were low. Endothelial cell loss secondary to phakic toric IOLs might be a concern over the long-term, particularly in iris-clipped IOLs in PKP eyes. Toric IOLs represent a viable option in the treatment of residual astigmatism in postkeratoplasty eyes, resulting in improved visual acuity and reduced anisometropia.
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- 2022
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5. Combined accelerated collagen crosslinking and sub-Bowman’s keratomileusis in high myopic eyes: a comparison between total ultraviolet energy dose
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Kelvin H, Wan, Tommy Cy, Chan, Peter Sk, Kwok, and Alex Lk, Ng
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Ophthalmology ,Photosensitizing Agents ,Ultraviolet Rays ,Keratomileusis, Laser In Situ ,Myopia ,Humans ,Lasers, Excimer ,Collagen ,General Medicine ,Refraction, Ocular ,Retrospective Studies - Abstract
To compare the safety, efficacy, and predictability outcomes of combined sub-Bowman's keratomileusis (thin flap laser in situ keratomileusis [LASIK]) and accelerated crosslinking (CXL) using two different irradiation durations.A retrospective comparative study of patients with percent tissue altered ≥35%, undergoing simultaneous CXL during sub-Bowman's keratomileusis were recruited. Following riboflavin application, they underwent ultraviolet-A (UVA) irradiation (18 mW/cmThe baseline characteristics were similar between the 40 eyes/patients treated using the 2-min protocol and the 33 eyes/patients treated with the 3-min protocol (A comparable volume of crosslinked corneal tissue can be achieved by using a shorter UVA irradiation duration. Additional duration of UVA irradiation could lead to delay in visual rehabilitation after simultaneous sub-Bowman's keratomileusis and CXL.
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- 2022
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6. Ocular surface disturbance in patients after acute COVID‐19
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Kelvin H. Wan, Grace C. Y. Lui, Ken C. F. Poon, Susanna S. S. Ng, Alvin L. Young, David S. C. Hui, Clement C. Y. Tham, Paul K. S. Chan, Chi Pui Pang, and Kelvin K. L. Chong
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Oxygen ,Ophthalmology ,COVID-19 Testing ,Tears ,Eyelid Diseases ,COVID-19 ,Humans ,Meibomian Glands ,Dry Eye Syndromes ,Meibomian Gland Dysfunction - Abstract
We investigated the ocular surface disturbances in COVID-19 patients discharged from the hospital.One hundred and seventy-nine eyes of 109 healthy participants and 456 eyes of 228 post-COVID-19 patients received comprehensive eye examinations; the latter were interviewed with questionnaires on ocular symptoms before and after COVID-19 diagnosis. Associations of ocular surface manifestations with virological and ophthalmic parameters were evaluated by multivariable mixed linear or logistic regression models.Mean interval between COVID-19 diagnosis and ophthalmic evaluation was 52.23 ± 16.12 days. The severity of meibomian gland dysfunction (MGD) based on clinical staging was higher in post-COVID-19 than healthy eyes (1.14 ± 0.67 vs. 0.92 ± 0.68, p = 0.002) and so was ocular surface staining score (0.60 ± 0.69 vs. 0.49 ± 0.68, p = 0.044). Patients requiring supplementary oxygen during hospitalisation had shorter tear break-up time (β -1.63, 95% CI -2.61 to -0.65). Cycle threshold (Ct) value from upper respiratory samples (inversely correlated with viral load) at diagnosis had an OR = 0.91 (95% CI 0.84-0.98) with new ocular surface symptoms 4 weeks after diagnosis. The presence of ocular surface symptoms 1 week prior to COVID-19 diagnosis showed an OR of 20.89 (95% CI 6.35-68.66) of persistent or new ocular symptoms 4 weeks afterward.MGD and ocular surface staining are more common and severe in post-COVID-19 patients. Patients with higher viral loads have greater risks of ocular surface symptoms. Patients requiring supplementary oxygen are more likely to show tear film instability. Ocular surface evaluation should be considered 1-3 months following hospital discharge for any COVID-19 patient.
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- 2022
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7. Flipped Classroom Case Learning vs Traditional Lecture-Based Learning in Medical School Ophthalmology Education: A Randomized Trial
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Poemen P. Chan, Vivian W.Y. Lee, Jason C. Yam, Marten E. Brelén, Wai Kit Chu, Kelvin H. Wan, Li Jia Chen, Clement C Tham, and Chi Pui Pang
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General Medicine ,Education - Published
- 2023
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8. COVID-19: Update on Its Ocular Involvements, and Complications From Its Treatments and Vaccinations
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Kenny H W Lai, Timothy P H Lin, Chung-Nga Ko, Dennis Lam, Raymond L. M. Wong, Ke Zheng, Allie Lee, Shaochong Zhang, Suber S Huang, and Kelvin H Wan
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medicine.medical_specialty ,Coronavirus disease 2019 (COVID-19) ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,MEDLINE ,Review Article ,vaccine-related eye problems ,Pandemic ,medicine ,Humans ,Clinical care ,Intensive care medicine ,Pandemics ,T001 ,Ophthalmologists ,business.industry ,SARS-CoV-2 ,complications from treatment ,Vaccination ,ocular involvement ,COVID-19 ,General Medicine ,medicine.disease ,Ophthalmology ,Pneumonia ,Etiology ,business - Abstract
The coronavirus disease 2019 (COVID-19) came under the attention of the international medical community when China first notified the World Health Organization of a pneumonia outbreak of then-unknown etiology in Wuhan in December 2019. Since then, COVID-19 caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has appalled the world by spreading at a pandemic speed. Although ophthalmologists do not directly engage in the clinical care of COVID-19 patients, the ophthalmology community has become aware of the close ties between its practice and the pandemic. Not only are ophthalmologists at heightened risk of SARS-CoV-2 exposure due to their physical proximity with patients in routine ophthalmic examinations, but SARS-CoV-2 possesses ocular tropism resulting in ocular complications beyond the respiratory tract after viral exposure. Furthermore, patients could potentially suffer from adverse ocular effects in the therapeutic process. This review summarized the latest literature to cover the ophthalmic manifestations, effects of treatments, and vaccinations on the eye to aid the frontline clinicians in providing effective ophthalmic care to COVID-19 patients as the pandemic continues to evolve.
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- 2021
9. Late-Onset Nontuberculous Mycobacterial Keratitis After Small Incision Lenticule Extraction
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Kelvin H Wan, Julia T. W. Lam, Vanissa W. S. Chow, and Nai Man Lam
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Adult ,Keratitis ,medicine.medical_specialty ,business.industry ,Keratomileusis, Laser In Situ ,Mycobacterial keratitis ,Late onset ,Mycobacterium chelonae ,Anti-Bacterial Agents ,Ophthalmology ,Humans ,Small incision lenticule extraction ,Medicine ,Female ,business - Abstract
The purpose of this article was to report a case of unilateral late-onset nontuberculous mycobacterial keratitis after small incision lenticule extraction (SMILE).This was a case report.A 27-year-old woman presented with Mycobacterium chelonae keratitis 3 weeks after uncomplicated SMILE with a solitary interface infiltrate. The keratitis worsened after an initial response to topical fortified and interface antibiotic irrigation. Despite repeated interface irrigation and topical and oral antibiotics, progressive, diffuse stromal infiltrates followed by melting of the cap ensued over the next 6 weeks. Cap amputation and intrastromal antibiotic injection followed by prolonged topical and oral antibiotics usage for the following 5 weeks led to infiltrate resolution and re-epithelization of the residual stromal bed. All medications were tapered off over 6 months after initial presentation without recurrence, but anterior stromal scarring and corneal neovascularization persisted.Cap amputation and intrastromal antibiotic injection for intractable post-SMILE keratitis can prevent the need for therapeutic keratoplasty.
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- 2021
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10. Bilateral synchronous conjunctival myxoma and review of the literature
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Timothy P.H. Lin, Kelvin H. Wan, Wah Cheuk, Enne Leung, Hunter K.L. Yuen, and Dennis S.C. Lam
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Ophthalmology ,General Medicine - Abstract
Purpose The purpose of this study was to report the clinicopathological features and management of the first case of bilateral synchronous conjunctival myxoma. Methods This study was a case report and literature review. Results A 66-year-old Chinese male with past ocular history of uncomplicated bilateral phacoemulsification and intraocular lens (IOLs) 3 years ago prior to presentation presented with bilateral red and swollen conjunctiva for over a year. On examination his corrected distance visual acuity (CDVA) was 25/20 in the right eye 20/20 in the left eye. Slit lamp examination revealed swollen temporal conjunctiva bilaterally which appeared as painless, well-circumscribed, salmon-pink, fleshy patches. The lesion in the right eye was subsequently excised, followed by excision of the lesion in the left eye at 3-week interval. Microscopically, histopathological examination of both excised specimens revealed hypocellular conjunctival mucosa covered by non-dysplastic epithelium, with presence of myxoid degeneration in the subepithelial stroma and immunostaining findings consistent with conjunctival myxoma. At his latest follow-up at 24 months, there were no recurrences of the conjunctival masses and the CDVA was the same as preoperatively.
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- 2022
11. Enhanced Monofocal Versus Conventional Monofocal Intraocular Lens in Cataract Surgery: A Meta-analysis
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Kelvin H. Wan, Andrea C.K. Au, Wee Nie Kua, Alex L.K. Ng, George P.M. Cheng, Nai Man Lam, and Vanissa W.S. Chow
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Lenses, Intraocular ,Ophthalmology ,Phacoemulsification ,Lens Implantation, Intraocular ,Patient Satisfaction ,Visual Acuity ,Humans ,Surgery ,Cataract Extraction ,Capsule Opacification ,Prosthesis Design - Abstract
PURPOSE: To compare different outcomes of an enhanced monofocal intraocular lens (IOL) versus a conventional monofocal IOL implantation after cataract surgery. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline was used for abstracting data and assessing quality. Comparative studies between enhanced monofocal versus conventional monofocal IOL implantations reporting outcomes in monocular and binocular visual acuities at various distances, spectacle independence, contrast sensitivity, optical quality, and adverse effects were identified from three databases. Meta-analysis, sensitivity analysis, and subgroup analysis were performed. RESULTS: A total of 680 eyes implanted with an enhanced monofocal IOL (Tecnis Eyhance ICB00; Johnson & Johnson) and 647 eyes with a conventional monofocal IOL from 3 randomized controlled trials and 9 comparative studies were included. The enhanced monofocal IOL showed better monocular uncorrected intermediate visual acuity (UIVA) (mean difference [MD]: −0.11 logMAR; 95% CI: −0.12 to −0.09), binocular UIVA (MD: −0.17 logMAR; 95% CI: −0.23 to −0.11), and binocular uncorrected near visual acuity performance (MD: −0.17 logMAR; 95% CI: −0.29 to −0.04) than the conventional monofocal IOL. More patients were spectacle free at intermediate distance with the enhanced monofocal IOL (odds ratio: 12.9; 95% CI: 6.2 to 27.0). Both monocular (MD: −0.002 logMAR; 95% CI: −0.01 to 0.01) and binocular (MD: 0.01 logMAR; 95% CI: −0.02 to 0.03) uncorrected distance visual acuity revealed non-significant differences between the IOL designs. Contrast sensitivity, photic phenomenon, and adverse effects were comparable. CONCLUSIONS: Enhanced monofocal IOLs effectively improved unaided intermediate vision with similar distance performance relative to conventional monofocal IOLs. This was achieved without compromising the contrast sensitivity or inducing photic phenomena. [ J Refract Surg . 2022;38(8):538–546.]
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- 2022
12. Wavefront aberrometry repeatability and agreement-A comparison between Pentacam AXL Wave, iTrace and OPD-Scan III
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Kelvin H. Wan, Xu Lin Liao, Marco Yu, Rachel W. Y. Tsui, Vanissa W. S. Chow, Kelvin K. L. Chong, and Tommy C. Y. Chan
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Ophthalmology ,Aniline Compounds ,Corneal Wavefront Aberration ,Aberrometry ,Humans ,Reproducibility of Results ,Refraction, Ocular ,Sensory Systems ,Optometry ,Retinoscopy - Abstract
To compare intrasession agreement and repeatability of wavefront aberration measurements from three different aberrometers obtained using Hartmann-Shack, ray tracing and automated retinoscopy methods, as well as their interdevice agreement.Three consecutive measurements were obtained using the Pentacam AXL Wave, the iTrace and the OPD-Scan III in 47 eyes of 47 patients. Wavefront refractions, root mean square of total aberrations (RMS total), RMS of higher-order aberrations (HOA) and second-, third- and fourth-order HOAs were exported for 4-mm pupils. Wavefront refractions were converted into vector components: M, JThe intrasession agreement and repeatability of RMS HOA were comparable between the three devices; both the Pentacam AXL Wave and the OPD-Scan III had better intrasession agreement and repeatability for the RMS total than the iTrace (p ≤ 0.02). Intrasession repeatability for the majority of second- and third-order aberrations was better on the Pentacam AXL Wave than on the iTrace (p ≤ 0.01) and OPD-Scan III (p ≤ 0.04), although their agreement and repeatability in spherical aberration were comparable (p ≥ 0.24). Significant systematic differences and proportional bias were detected for almost all refraction power vectors and Zernike coefficients among the three devices.In this study, all three devices provided good-to-excellent agreement for aberration measurements. Most of the individual Zernike's components were not exchangeable between different aberrometers. Their relative intrasession performance in agreement and repeatability varied significantly across different ocular aberration parameters.
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- 2022
13. Transepithelial corneal collagen cross‐linking using iontophoresis versus the Dresden protocol in progressive keratoconus: A meta‐analysis
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George P.M. Cheng, Vishal Jhanji, Vanissa W. S. Chow, Kelvin K.L. Chong, Christina K Y Ip, Alvin L. Young, Wee Nie Kua, and Kelvin H Wan
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Keratoconus ,medicine.medical_specialty ,Ultraviolet Rays ,Riboflavin ,Corneal collagen cross-linking ,Subgroup analysis ,law.invention ,Meta-Analysis as Topic ,law ,Ophthalmology ,medicine ,Humans ,Coma ,Photosensitizing Agents ,Keratometer ,business.industry ,Corneal Topography ,Odds ratio ,Iontophoresis ,medicine.disease ,Confidence interval ,Cross-Linking Reagents ,Photochemotherapy ,Collagen ,medicine.symptom ,Complication ,business - Abstract
Background Standard epithelium-off collagen cross-linking using Dresden protocol (S-CXL) is the standard of care for progressive keratoconus. Despite its efficacy, epithelial debridement is associated with pain, delayed visual rehabilitation, stromal oedema and haze. Minimising these complications while achieving a comparable efficacy remains an unmet need. Methods Comparative studies between transepithelial iontophoresis-assisted CXL (I-CXL) and S-CXL reporting the outcomes of visual, refractive, topographic, aberrometry, demarcation line, endothelial cell density, confocal microscopy or complications were identified from databases. Assessments of publication bias, meta-analyses, sensitivity analysis, subgroup analysis, and meta-regressions were performed. Results In this meta-analysis, 586 eyes from three randomised controlled trials and seven comparative studies were analysed. No differences were found in the change in uncorrected/corrected distance visual acuities, mean/maximum keratometry, central corneal thickness, higher order aberration, spherical aberration, coma, subbasal nerve/anterior stromal keratocyte density and demarcation line depth in both CXL protocols (P ≥ .052). However, I-CXL resulted in less thinning at the minimum pachymetry (standardised mean difference 0.25; 95% confidence interval [CI] 0.06-0.44). More importantly, there was a significant reduction in complications following I-CXL (odds ratio 0.30; 95% CI 0.12-0.75). Meta-regression analyses on demarcation line depth and complication suggested that I-CXL was more effective than S-CXL when baseline maximum keratometry was >55.2 D and the risk of complication was independent of other baseline covariates. Conclusion I-CXL has a more favourable safety profile, as evidenced by the available literature, with less thinning at the minimum pachymetry and reduced risk of complications while achieving comparable effects on visual, refractive, topographic, aberrometry, and morphological outcomes as S-CXL.
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- 2021
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14. Management of cytomegalovirus corneal endotheliitis
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Kelvin H Wan, Wee Nie Kua, Alvin L. Young, and Angela Wong
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0301 basic medicine ,Ganciclovir ,medicine.medical_specialty ,Congenital cytomegalovirus infection ,Cytomegalovirus ,Review ,Cornea ,03 medical and health sciences ,0302 clinical medicine ,lcsh:Ophthalmology ,Medicine ,Endotheliitis ,Corneal Decompensation ,business.industry ,Corneal Diseases ,CMV ,Corneal Transplant ,Valganciclovir ,medicine.disease ,Dermatology ,Corneal transplant ,030104 developmental biology ,medicine.anatomical_structure ,lcsh:RE1-994 ,Keratoplasty ,030221 ophthalmology & optometry ,business ,medicine.drug - Abstract
Background Cytomegalovirus (CMV) can manifest as corneal endotheliitis in immunocompetent individuals. Early diagnosis is prudent to prevent endothelial cell loss, which could ultimately lead to corneal decompensation. CMV DNA was first detected in an eye with corneal endotheliitis in 2006; since then, clinical evidence from numerous case reports and case series have accumulated. Main text In this narrative review, we identified several drugs, including ganciclovir, valganciclovir, and their combination in oral, intravenous, intravitreal, and topical forms in different concentrations, together with the judicious use of topical steroids, have reported variable success. There has yet to be any prospective comparative study evaluating the efficacy and safety of these assorted forms of treatment; clinical evidence is based on case reports and case series. CMV endotheliitis presenting with corneal edema can masquerade as other corneal diseases and thus poses a great challenge especially in post-keratoplasty eyes. Heightened awareness is needed before and after keratoplasty to start prompt prophylaxis and treatment. Conclusion There is no consensus on the management of CMV endotheliitis. Further studies are much needed to elucidate the optimal treatment modality, regime, and duration in the treatment and prophylaxis of CMV endotheliitis.
- Published
- 2021
15. COVID-19: Ocular Manifestations and the APAO Prevention Guidelines for Ophthalmic Practices
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Kenny H W Lai, Chung-Nga Ko, Clement C Y Tham, Suber S Huang, Kelvin H Wan, Daniel S W Ting, Dennis S.C. Lam, Raymond L. M. Wong, and Paisan Ruamviboonsuk
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medicine.medical_specialty ,Eye Diseases ,Coronavirus disease 2019 (COVID-19) ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Pneumonia, Viral ,World health ,Betacoronavirus ,ophthalmic practice ,03 medical and health sciences ,0302 clinical medicine ,Pandemic ,Health care ,Disease Transmission, Infectious ,Humans ,Medicine ,Potential source ,Intensive care medicine ,Pandemics ,Societies, Medical ,SARS-CoV-2 ,business.industry ,ocular involvement ,COVID-19 ,General Medicine ,medicine.disease ,Ophthalmology ,Pneumonia ,Practice Guidelines as Topic ,030221 ophthalmology & optometry ,preventive measures ,Tears ,Coronavirus Infections ,business ,030217 neurology & neurosurgery ,Perspectives - Abstract
The World Health Organization declared the Coronavirus Disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 a “Pandemic” on March 11, 2020. As of June 1, 2020, Severe Acute Respiratory Syndrome Coronavirus 2 has infected >6.2 million people and caused >372,000 deaths, including many health care personnel. It is highly infectious and ophthalmologists are at a higher risk of the infection due to a number of reasons including the proximity between doctors and patients during ocular examinations, microaerosols generated by the noncontact tonometer, tears as a potential source of infection, and some COVID-19 cases present with conjunctivitis. This article describes the ocular manifestations of COVID-19 and the APAO guidelines in mitigating the risks of contracting and/or spreading COVID-19 in ophthalmic practices.
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- 2020
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16. Minimally Invasive Glaucoma Surgery in Primary Angle-Closure Glaucoma
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Yunhe, Song, Hengli, Zhang, Yingzhe, Zhang, Guangxian, Tang, Kelvin H, Wan, Jacky W Y, Lee, Nathan, Congdon, Mingzhi, Zhang, Mingguang, He, Clement C, Tham, Christopher K S, Leung, Robert N, Weinreb, Dennis S C, Lam, and Xiulan, Zhang
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Phacoemulsification ,Humans ,Trabeculectomy ,Glaucoma, Angle-Closure ,Glaucoma, Open-Angle ,Intraocular Pressure - Abstract
Primary angle-closure glaucoma (PACG) is responsible for half of the glaucoma-related blindness worldwide. Cataract surgery with or without trabeculectomy has been considered to be the first-line treatment in eyes with medically uncontrolled PACG. While minimally invasive glaucoma surgery has become an important surgical approach for primary open-angle glaucoma, its indications and benefits in PACG are less clear. This review summarizes the efficacy and safety profile of minimally invasive glaucoma surgery in PACG to unfold new insights into the surgical management of PACG.
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- 2022
17. Impact of Digital Technology on Eye Diseases During COVID-19
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Kelvin H, Wan and Jost B, Jonas
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Digital Technology ,Ophthalmology ,Eye Diseases ,SARS-CoV-2 ,COVID-19 ,Humans ,General Medicine - Published
- 2022
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18. Nicotinamide riboside as a neuroprotective therapy for glaucoma: study protocol for a randomized, double-blind, placebo-control trial
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Cedric Ka Fai Yiu, Match W L Ko, Aziz Kam, Kelvin H Wan, Poemen P. Chan, Vivian Chiu, Seraph Tianmin Ren, Marco Yu, Gilda Lai, and Christopher Kai-Shun Leung
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Niacinamide ,Retinal Ganglion Cells ,Medicine (General) ,genetic structures ,Glaucoma ,Medicine (miscellaneous) ,Pyridinium Compounds ,Pharmacology ,Placebo ,Neuroprotection ,Double blind ,Study Protocol ,chemistry.chemical_compound ,R5-920 ,Nerve Fibers ,Text mining ,Humans ,Multicenter Studies as Topic ,Medicine ,Pharmacology (medical) ,Randomized Controlled Trials as Topic ,Progressive retinal nerve fiber layer thinning ,Protocol (science) ,Optical coherence tomography ,business.industry ,medicine.disease ,Visual field ,eye diseases ,Nicotinamide riboside ,Retinal nerve fiber layer ,chemistry ,sense organs ,Visual Fields ,business ,Glaucoma, Open-Angle - Abstract
Background Whereas lowering the intraocular pressure (IOP) can slow optic nerve degeneration in glaucoma, many patients with glaucoma continue to develop progressive loss in vision despite a significant reduction in IOP. No treatment has been shown to be effective for neuroprotection in glaucoma. We set out to conduct a randomized controlled trial to investigate whether nicotinamide riboside (NR), a nicotinamide adenine dinucleotide precursor, is effective to slow optic nerve degeneration in patients with primary open-angle glaucoma (POAG). We hypothesize that patients treated with NR have a slower rate of progressive retinal nerve fiber layer (RNFL) thinning compared with those treated with placebo. Methods This is a randomized, double-blind, placebo-controlled, parallel-group, multi-center study including 125 patients with POAG. Patients will be randomized to receive 300 mg NR or placebo for 24 months. Clinical examination, optical coherence tomography imaging of the RNFL, and visual field (VF) test will be performed at the baseline, 1 month, 4 months, and then at 2-month intervals until 24 months. The primary outcome measure is the rate of RNFL thinning measured over 24 months. The secondary outcome measures include (1) time to VF progression, (2) time to progressive RNFL/ganglion cell inner plexiform layer (GCIPL) thinning, and (3) the rate of change of VF sensitivity over 24 months (to investigate neuroprotection) and 1 month (to investigate neuroenhancement). The rates of RNFL thinning and VF sensitivity decline between treatment groups will be compared with linear mixed modeling. Survival analysis will be performed to compare the differences in time from baseline to VF progression and time from baseline to progressive RNFL/GCIPL thinning between treatment groups using Cox proportional hazards models. Discussion Outcome measures in glaucoma neuroprotection trials have been centered on the detection of VF progression, which may take years to develop and confirm. In addition to addressing whether NR has a neuroprotective/neuroenhancement effect in glaucoma patients, this study will demonstrate the feasibility of studying neuroprotection in a relatively short trial period (24 months) by comparing the rates of progressive RNFL thinning, a more reproducible and objective outcome measure compared with VF endpoints, between treatment groups. Trial registration Chinese Clinical Trial Registry 1900021998
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- 2022
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19. Outcomes and prognostic factors of cataract surgery in cytomegalovirus-related anterior uveitis
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Kelvin H. Wan, Ke Liu, Nai Man Lam, and Vanissa W.S. Chow
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Phacoemulsification ,Vision Disorders ,Cytomegalovirus ,Glaucoma ,Prognosis ,Uveitis, Anterior ,Sensory Systems ,Cataract ,Uveitis ,Ophthalmology ,Postoperative Complications ,Lens Implantation, Intraocular ,Cytomegalovirus Infections ,Humans ,Surgery ,Ganciclovir ,Follow-Up Studies ,Retrospective Studies - Abstract
To evaluate the outcomes of cataract surgery in patients with cytomegalovirus (CMV) anterior uveitis and factors associated with final visual outcome.Hong Kong Eye Hospital, Hong Kong.Retrospective case series.History, clinical characteristics, corrected distance visual acuity (CDVA), medications, and complications of CMV anterior uveitic eyes that underwent cataract surgery between 2010 and 2020 were reviewed.This study included 26 eyes of 26 patients undergoing phacoemulsification. The median duration of disease was 4.8 years, and the median quiescent period preoperatively was 2.3 years. None required pupil manipulation or had significant intraoperative complications. The median CDVA improved from 20/100 (interquartile range [IQR] 20/200 to 20/50) preoperatively to 20/30 (IQR 20/40 to 20/25) at 1 year and 20/35 (IQR 20/50 to 20/30) at the last follow-up at a median of 4.9 years postoperatively ( P.001). CDVA improved in 19 eyes (73.1%) and was ≥20/40 in 18 eyes (69.2%). In the multivariate regression model, preoperative use of topical 0.15% ganciclovir (β = 0.33, 95% CI 0.17 to 0.48, P.001) and adjunctive intraoperative intracameral dexamethasone 0.4 mg (β = 0.19, 95% CI 0.01 to 0.36, P = .043) were associated with a better final CDVA. Loss of CDVA and poor postoperative CDVA visual acuity were mostly attributed to uveitic glaucoma, but preoperative glaucoma or the number of antiglaucoma medications did not affect final CDVA.Cataract surgery in eyes with CMV anterior uveitis was safe and CDVA significantly improved and remained sustained postoperatively. Topical ganciclovir 0.15% preoperatively and intracameral corticosteroid intraoperatively seem to maximize the final visual outcome.
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- 2022
20. Comment on: Quality of Life in Primary Open-Angle Glaucoma and Cataract: An Analysis of VFQ-25 and OSDI from the iStent inject® Pivotal Trial
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Kelvin H Wan and Clement C Y Tham
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Ophthalmology ,Quality of life (healthcare) ,Open angle glaucoma ,business.industry ,Optometry ,Medicine ,business - Published
- 2022
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21. Accuracy and Precision of Intraocular Lens Calculations Using the New Hill-RBF Version 2.0 in Eyes With High Axial Myopia
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Thomas C.H. Lam, Tommy C Y Chan, Kelvin H Wan, and Marco Yu
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Male ,Optics and Photonics ,medicine.medical_specialty ,Refractive error ,Accuracy and precision ,Biometry ,medicine.medical_treatment ,Intraocular lens ,Refraction, Ocular ,Cataract ,Standard deviation ,03 medical and health sciences ,0302 clinical medicine ,Ophthalmology ,Myopia ,medicine ,Humans ,Dioptre ,Aged ,Retrospective Studies ,030304 developmental biology ,Mathematics ,Variance function ,Lenses, Intraocular ,0303 health sciences ,Phacoemulsification ,Reproducibility of Results ,medicine.disease ,Refraction ,Axial Length, Eye ,030221 ophthalmology & optometry ,Female - Abstract
Purpose To compare the accuracy and precision of the new Hill-RBF version 2.0 (Hill-RBF 2) formula with other formulas (Barrett Universal II, Haigis, Hoffer Q, Holladay 1, and SRK/T) in predicting residual refractive error after phacoemulsification in high axial myopic eyes. Design Retrospective case series. Methods 127 eyes of 127 patients with axial length (AL) ≥26 mm were included. The refractive prediction error (PE) was calculated as the difference between the postoperative refraction and the refraction predicted by each formula for the intraocular lens (IOL) power actually implanted. Standard deviation (SD) of PE, median absolute PE (MedAE), proportion of eyes within ±0.25, ±0.50, and ±1.00 diopter (D) of PE were compared. A generalized linear model was used to model the mean function and variance function of the PE (indicative of the accuracy and precision) with respect to biometric variables. Results The MedAE and SD of Hill-RBF 2 were lower than that of Hoffer Q, Holladay 1, and SRK/T (P ≤ .036) and were comparable to Barrett Universal II and Haigis (P ≥ .077). Hill-RBF 2 had more eyes within ±0.25 D of the intended refraction (76 out of 127 eyes [59.84%]) compared to other formulas (P ≤ .034) except Barrett Universal II (P = .472). AL was associated with the mean function or variance function of the PE for all formulas except Hill-RBF 2. Conclusions In this study, the precision of Hill-RBF 2 is comparable to Barret Universal II and Haigis. Unlike the other 5 formulas, its dispersion and the accuracy of the refractive prediction is independent of the AL.
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- 2019
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22. Dry Eyes After SMILE
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Tommy C Y Chan, Wee Nie Kua, Kelvin H Wan, Angela Wong, Rachel K Y Cheung, and Kendrick Co Shih
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medicine.medical_specialty ,Visual acuity ,genetic structures ,Corneal Stroma ,medicine.medical_treatment ,Keratomileusis, Laser In Situ ,Visual Acuity ,Keratomileusis ,Signs and symptoms ,Review Article ,03 medical and health sciences ,Postoperative Complications ,0302 clinical medicine ,Corneal Sensitivity ,Ophthalmology ,Myopia ,Humans ,Medicine ,Small incision lenticule extraction ,dry eyes ,SMILE ,business.industry ,Dry eyes ,General Medicine ,medicine.disease ,eye diseases ,refractive surgery ,030221 ophthalmology & optometry ,Dry Eye Syndromes ,Lasers, Excimer ,sense organs ,medicine.symptom ,business ,Ocular surface ,030217 neurology & neurosurgery - Abstract
Dry eyes is one of the most common complications after laser vision correction. Small incision lenticule extraction (SMILE) is a flapless procedure with a smaller corneal incision, less corneal nerves are transected during, making it theoretically less prone to dry eyes. Both SMILE and femtosecond-laser-assisted in situ keratomileusis (FS-LASIK) induce a transient worsening in dry eye parameters, but there is evidence showing that SMILE holds promises to have fewer negative impacts on the ocular surface parameters and allow an earlier recovery. SMILE-treated eyes may also have shown less corneal denervation and better corneal sensitivity compared with FS-LASIK eyes. This review summarizes the mechanisms of dry eyes after laser vision correction, the short-term (≤6 months) and long-term (>6 months) results in changes to dry eyes signs and symptoms, and corneal sensitivity of SMILE, as compared with FS-LASIK. Limitation of the studies and reasons accounting for their discrepancies will be discussed. Future randomized controlled trials with standardized postoperative regime are needed for better evaluation of dry eyes after SMILE.
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- 2019
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23. Paediatric glaucoma in Hong Kong: a multicentre retrospective analysis of epidemiology, presentation, clinical interventions, and outcomes
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Susanna Tsang, Kelvin H Wan, Geoffrey C Tang, Joyce J. Chan, Jonathan C Ho, Clement C Y Tham, Wilson W K Yip, and Nafees Baig
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Male ,Intraocular pressure ,medicine.medical_specialty ,Visual acuity ,genetic structures ,Photophobia ,Visual Acuity ,Glaucoma ,Ophthalmologic Surgical Procedures ,Ophthalmology ,Epidemiology ,Prevalence ,medicine ,Cluster Analysis ,Humans ,Child ,Strabismus ,Intraocular Pressure ,business.industry ,Child Health ,Retrospective cohort study ,medicine.disease ,eye diseases ,Child, Preschool ,Hong Kong ,Female ,sense organs ,medicine.symptom ,business ,Uveitis - Abstract
Purpose To document the epidemiology, presentation, clinical interventions, and outcomes of paediatric glaucoma in Hong Kong. Methods This multicentre territory-wide retrospective study was performed by reviewing charts of patients with paediatric glaucoma in six clusters of the Hong Kong Hospital Authority and The Chinese University of Hong Kong from 2006 to 2015. Results This study included 150 eyes of 98 patients with paediatric glaucoma (presenting age: 5.2±5.7 years). Of them, 35 eyes (23.3%) had primary congenital glaucoma, 22 eyes (14.7%) had juvenile open-angle glaucoma, and 93 eyes (62.0%) had secondary glaucoma. The most prevalent types of secondary glaucoma were lens-related after cataract extraction (18.0%), Axenfeld-Rieger anomaly (5.3%), uveitis (5.3%), Sturge-Weber syndrome (4.7%), and traumatic (3.3%). The most common clinical presentations were parental concerns (20.7%) including cloudy cornea (12.7%) and tearing/photophobia (8.0%), followed by poor visual acuity (18.0%), high intraocular pressure (13.3%), and strabismus (6.0%). The follow-up duration was 8.46±6.51 years. Furthermore, 63.2% of eyes with primary glaucoma and 45.2% of eyes with secondary glaucoma were treated surgically. The final visual acuity was 0.90±0.98 LogMAR; intraocular pressure was 18.4±6.6 mm Hg; and number of glaucoma medications was 2.22±1.61. Conclusion Primary congenital glaucoma was most prevalent, followed by juvenile open-angle glaucoma and aphakic glaucoma. Most eyes with primary glaucoma required surgical treatment. Parental concerns were important clinical presentations. Basic assessments by healthcare providers to identify glaucoma signs (eg, poor visual acuity, high intraocular pressure, and strabismus) warranted prompt referral to an ophthalmologist.
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- 2021
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24. Immediate transepithelial photorefractive keratectomy after suction loss during SMILE
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Kelvin H Wan, Kenny H W Lai, Dennis Lam, and Timothy P H Lin
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Suction (medicine) ,medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Suction ,Photorefractive Keratectomy ,Sensory Systems ,Photorefractive keratectomy ,Ophthalmology ,Myopia ,Medicine ,Humans ,Surgery ,Lasers, Excimer ,business - Published
- 2020
25. Options and results in managing suction loss during small-incision lenticule extraction
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Timothy P H Lin, Kelvin H Wan, Shu Liu, Kenny H W Lai, and Dennis Lam
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Suction (medicine) ,medicine.medical_specialty ,Intraoperative Complication ,medicine.medical_treatment ,Corneal Stroma ,Keratomileusis, Laser In Situ ,Visual Acuity ,Keratomileusis ,Suction ,Refraction, Ocular ,03 medical and health sciences ,0302 clinical medicine ,Myopia ,Medicine ,Humans ,Retrospective Studies ,business.industry ,Sensory Systems ,Photorefractive keratectomy ,Surgery ,Ophthalmology ,030221 ophthalmology & optometry ,Lasers, Excimer ,Level ii ,business ,030217 neurology & neurosurgery - Abstract
Suction loss is an intraoperative complication in small-incision lenticule extraction (SMILE) that presents a management challenge for the refractive surgeon. The purpose of this review is to evaluate the visual, refractive, and wavefront outcomes after suction loss across the different stages of SMILE with various respective surgical treatments. Surgical management options include immediate re-SMILE by redocking or delayed re-SMILE, with or without adjustment of the laser parameters, conversion to femtosecond laser in situ keratomileusis, transepithelial photorefractive keratectomy, refractive lenticule extraction, or pseudo-SMILE. The restart treatment module on VisuMax provides appropriate retreatment recommendation. Most retreatment options for suction loss, immediate or delayed, resulted in effective, safe, and predictable outcomes, and patients were satisfied with their outcomes. Based on available level II evidence, immediate re-SMILE with or without adjustment to the laser settings achieve favorable visual and refractive outcomes in handling this intraoperative complication across all stages of SMILE.
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- 2020
26. Death tolls of COVID-19: Where come the fallacies and ways to make them more accurate
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David S.C. Hui, Timothy P H Lin, Suber S Huang, Kelvin H Wan, Jost B. Jonas, and Dennis S.C. Lam
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2019-20 coronavirus outbreak ,History ,Coronavirus disease 2019 (COVID-19) ,media_common.quotation_subject ,Pneumonia, Viral ,03 medical and health sciences ,Politics ,Betacoronavirus ,0302 clinical medicine ,Development economics ,Pandemic ,Humans ,030212 general & internal medicine ,Baseline (configuration management) ,Pandemics ,media_common ,030505 public health ,SARS-CoV-2 ,Public Health, Environmental and Occupational Health ,Censorship ,COVID-19 ,Data Accuracy ,Death toll ,Mortality data ,0305 other medical science ,Coronavirus Infections - Abstract
The death toll of the coronavirus disease 2019 (COVID-19) sparked much controversy since its advent in December 2019. Underestimation because of under testing and deaths happening outside the hospitals were important causes. Bold revisions of the diagnostic criteria leading to dramatic changes in death tolls by different governments were observed in attempts to generate more accurate estimates. On the other hand, the influence, censorship and manipulation on case and death data from top political leaders of some countries could create important impacts on the death toll. Baseline mortality data of previous years may help make more accurate estimates of the actual death toll. The pitfalls and strategies during such processes could become valuable lessons to leaders and policymakers worldwide as more accurate statistics serve to navigate policies to combat this pandemic in the days and months to come.
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- 2020
27. The end of ‘cordon sanitaire’ in Wuhan: the role of non-pharmaceutical interventions against COVID-19
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Kelvin H Wan, Chung-Nga Ko, Suber S Huang, and Dennis S.C. Lam
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2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,business.industry ,030503 health policy & services ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,quarantine ,coronavirus ,Psychological intervention ,Public Health, Environmental and Occupational Health ,COVID-19 ,General Medicine ,medicine.disease ,Public health measures ,non-pharmaceutical measures ,Article ,03 medical and health sciences ,0302 clinical medicine ,Medicine ,030212 general & internal medicine ,Medical emergency ,0305 other medical science ,business - Abstract
The effectiveness of the non-pharmaceutical interventions implemented in Wuhan are described and discussed. In the absence of vaccine and proven specific safe and effective treatments, the experience and results achieved by Wuhan could serve as a good reference for leaders and policymakers around the world in formulating their strategies and policies in fighting against COVID-19.
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- 2020
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28. Impact of COVID-19 on Ophthalmology and Future Practice of Medicine
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Dennis S.C. Lam, Timothy P H Lin, Kelvin H Wan, and Chung-Nga Ko
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2019-20 coronavirus outbreak ,Eye Diseases ,Coronavirus disease 2019 (COVID-19) ,Pneumonia, Viral ,MEDLINE ,Comorbidity ,Betacoronavirus ,Pandemic ,Disease Transmission, Infectious ,Humans ,Medicine ,Pandemics ,biology ,SARS-CoV-2 ,business.industry ,Viral Epidemiology ,COVID-19 ,General Medicine ,medicine.disease ,biology.organism_classification ,Virology ,Pneumonia ,Ophthalmology ,Coronavirus Infections ,business - Published
- 2020
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29. Risk of SARS-CoV-2 Transmission via Corneal Transplant From Donors With COVID-19
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Kelvin H Wan, Dennis S.C. Lam, and Vanissa W. S. Chow
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2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,SARS-CoV-2 ,business.industry ,Transmission (medicine) ,medicine.medical_treatment ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,COVID-19 ,Corneal Transplant ,Virology ,Tissue Donors ,Corneal Transplantation ,Ophthalmology ,Humans ,Medicine ,business ,Corneal transplantation - Published
- 2021
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30. Precautionary measures needed for ophthalmologists during pandemic of the coronavirus disease 2019 (COVID‐19)
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Dennis S.C. Lam, Alvin L. Young, Suber S Huang, and Kelvin H Wan
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medicine.medical_specialty ,Intraocular pressure ,Visual acuity ,genetic structures ,Coronavirus disease 2019 (COVID-19) ,Eye Diseases ,Internal medicine physicians ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Pneumonia, Viral ,03 medical and health sciences ,Betacoronavirus ,0302 clinical medicine ,Pandemic ,medicine ,Humans ,Pandemics ,Ophthalmologists ,business.industry ,SARS-CoV-2 ,COVID-19 ,General Medicine ,medicine.disease ,eye diseases ,Pneumonia ,Ophthalmology ,Editorial ,Emergency medicine ,030221 ophthalmology & optometry ,Red eye ,medicine.symptom ,business ,Coronavirus Infections ,030217 neurology & neurosurgery - Abstract
The novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) emerged in December 2019 in Wuhan, China has spread to over 113 countries with 118,326 infected and 4,292 died as of 11 March 2020 and the World Health Organization (WHO) has just announced COVID-19 a global pandemic. A person under investigation (PUI) for COVID-19 is less likely to present initially to the ophthalmologists compared to emergency care or internal medicine physicians. However, in late February 2020, 2 patients presented simultaneously to our eye casualty with sudden onset of unilateral painful red eye associated with a decline in visual acuity, their intraocular pressure (IOP) were over 40 mmHg and slit-lamp examination findings were suggestive of acute primary angle closure (APAC).
- Published
- 2020
31. Longitudinal evaluation of posterior corneal changes after laser in situ keratomileusis in high myopia: a swept-source optical coherence tomography study
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Kelvin H Wan, Tommy C Y Chan, Marco Yu, and Jhanji
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In situ ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,medicine.medical_treatment ,Follow up studies ,High myopia ,Keratomileusis ,Laser ,law.invention ,03 medical and health sciences ,Ophthalmology ,0302 clinical medicine ,Optical coherence tomography ,law ,030220 oncology & carcinogenesis ,030221 ophthalmology & optometry ,medicine ,Tomography ,business - Published
- 2018
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32. Fluctuation in straylight measurements during the visual recovery phase after small incision lenticule extraction
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Rachel W Y Tsui, Tommy C Y Chan, and Kelvin H Wan
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Adult ,medicine.medical_specialty ,Visual acuity ,Corneal Surgery, Laser ,Corneal Stroma ,Spherical equivalent ,Refraction, Ocular ,Article ,Myopic astigmatism ,Young Adult ,Preoperative level ,Ophthalmology ,Myopia ,Medicine ,Small incision lenticule extraction ,Humans ,Prospective Studies ,Prospective cohort study ,business.industry ,Astigmatism ,Postoperative visit ,Lasers, Excimer ,medicine.symptom ,business ,Recovery phase - Abstract
PURPOSE: To investigate the postoperative straylight changes during the visual recovery phase after small incision lenticule extraction (SMILE) and their association. METHODS: Seventy consecutive eyes from 37 patients with a mean age of 30.92 ± 7.26 years and a mean preoperative spherical equivalent of −5.24 ± 1.90 dioptres undergoing myopic or myopic astigmatism SMILE correction were included in this prospective study. Patients were followed up at days 1, 3, 7, 14, 21 and 28 after standard SMILE. Straylight was measured using the C-Quant straylight meter (Oculus GmbH, Germany) preoperatively and at each postoperative visit. RESULTS: Preoperatively, the mean straylight measurement was 1.16 ± 0.16. After SMILE, the mean straylight values were 1.12 ± 0.14 and 1.13 ± 0.13 at days 7 and 14, which were significantly reduced compared to preoperative values (p ≤ 0.028). Straylight returned to baseline by week 3 (p = 0.160) and remained stable onwards (p = 0.651). A lower ablation ratio was associated with less straylight level at days 1, 3, 14 and 21 (p ≤ 0.0497) in the multivariable regression model. Likewise, better visual acuity was associated with lower straylight at days 7, 14 and 28 postoperatively (p ≤ 0.038). A small proportion of eyes (range: 0–12.86%) had ≥0.30 log(s) increase in postoperative straylight within the first month after SMILE. CONCLUSIONS: SMILE induced a temporary decrease in straylight. It gradually returned to the preoperative level, which could be related to a number of dynamic processes during corneal healing. In the small proportion of patients with an increase in straylight postoperatively, this can affect their visual recovery during the early postoperative period.
- Published
- 2019
33. Repeatability and Agreement of a Swept-Source Optical Coherence Tomography-Based Biometer IOLMaster 700 Versus a Scheimpflug Imaging-Based Biometer AL-Scan in Cataract Patients
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Tommy C Y Chan, Marco Yu, Carol Y. Cheung, Yu Meng Wang, Fang Yao Tang, and Kelvin H Wan
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Male ,medicine.medical_specialty ,Materials science ,Biometry ,Intraclass correlation ,Scheimpflug principle ,Astigmatism ,Cataract ,law.invention ,Cornea ,03 medical and health sciences ,0302 clinical medicine ,Optical coherence tomography ,law ,Ophthalmology ,medicine ,Humans ,Prospective Studies ,Aged ,Reproducibility ,Keratometer ,medicine.diagnostic_test ,Reproducibility of Results ,Repeatability ,Axial length ,Equipment Design ,medicine.disease ,Axial Length, Eye ,Interferometry ,ROC Curve ,030221 ophthalmology & optometry ,Female ,030217 neurology & neurosurgery ,Tomography, Optical Coherence ,Follow-Up Studies - Abstract
Purpose To compare the repeatability and agreement between a swept-source biometer and a Scheimpflug biometer in cataract patients. Methods Three consecutive measurements were obtained using a swept-source biometer (IOLMaster 700) and a Scheimpflug biometer (AL-Scan) in 52 eyes of 52 patients. Keratometry, central corneal thickness (CCT), anterior chamber depth (ACD), axial length, and white-to-white (WTW) distance were recorded. Astigmatism values were transformed into vector components of J0 and J45. Intraoperator repeatability was analyzed using intraclass correlation coefficients (ICCs) and reproducibility coefficients (RCs). Agreement of measurements between the two devices was evaluated using the Bland-Altman method. Results The IOLMaster 700 showed higher ICCs and lower RCs for the mean keratometry (Km) (P≤0.018), CCT (P≤0.027), and ACD (P≤0.001) measurements, whereas the AL-Scan showed higher ICC and lower RC for the J45 vector component of astigmatism at the 2.4-mm zone (P≤0.034). Both the devices had excellent repeatability (ICC=0.999) in axial length measurement. Systematic differences were found in Km, CCT, ACD, and WTW (P≤0.018) between the devices. The mean difference for Km was -0.196 and -0.144 D measured at the 2.4-mm zone and 3.3-mm zone, respectively. The corresponding mean difference for CCT, ACD, and WTW distance was 14.92 μm, -0.017 mm, and 0.283 mm, respectively. These differences led to a statistically significant but clinically insignificant difference in the prediction of intraocular lens power. Conclusions This study showed significant differences in anterior segment measurement repeatability and agreement between a swept-source biometer and a Scheimpflug biometer in eyes with cataract.
- Published
- 2019
34. Conjunctival Findings in Patients With Coronavirus Disease 2019
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Suber S. Huang, Kelvin H Wan, and Dennis Lam
- Subjects
Ophthalmology ,2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Medicine ,In patient ,business ,Virology - Published
- 2021
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35. Comment on: Corneal Epithelial Thickness Measured Using AS-OCT as a Diagnostic Parameter for Limbal Stem Cell Deficiency
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Kelvin H Wan and Wee Nie Kua
- Subjects
medicine.medical_specialty ,business.industry ,Stem Cells ,Limbus Corneae ,Article ,Corneal Diseases ,Scleral Diseases ,Limbal stem cell deficiency ,Ophthalmology ,Humans ,Medicine ,business ,Tomography, Optical Coherence - Published
- 2020
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36. Update on the association between dry eye disease and meibomian gland dysfunction
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Hunter K.L. Yuen, Tommy C Y Chan, Kelvin H Wan, and Sharon S W Chow
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Diagnostic Imaging ,medicine.medical_specialty ,genetic structures ,Dry Eye Syndromes ,Disease ,03 medical and health sciences ,0302 clinical medicine ,Risk Factors ,Ophthalmology ,medicine ,Humans ,Fluorescent Dyes ,Randomized Controlled Trials as Topic ,Slit Lamp ,Staining and Labeling ,integumentary system ,business.industry ,Multifactorial disease ,Meibomian gland dysfunction ,Meibomian Glands ,General Medicine ,eye diseases ,Tears ,Eyelid Diseases ,030221 ophthalmology & optometry ,sense organs ,business ,Stepwise approach ,030217 neurology & neurosurgery - Abstract
Dry eye disease is one of the most common ophthalmic complaints; it results from the activity of various pathways and is considered a multifactorial disease. An important factor that contributes to the onset of dry eye disease is meibomian gland dysfunction. Meibomian gland dysfunction causes a disruption in the tear film lipid layer which affects the rate of tear evaporation. This evaporation leads to tear hyperosmolarity, eventually triggering the onset of dry eye disease. Dry eye disease and meibomian gland dysfunction are strongly associated with each other, such that many of their risk factors, signs, and symptoms overlap. This review aimed to provide an update on the association between dry eye disease and meibomian gland dysfunction. A stepwise approach for diagnosis and management is summarised.
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- 2019
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37. Effect of corneal curvature on optical zone decentration and its impact on astigmatism and higher-order aberrations in SMILE and LASIK
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Kelvin H Wan, Yan Wang, David S Y Kang, Tiffany Tso, Tommy C Y Chan, and George P.M. Cheng
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Adult ,Male ,medicine.medical_specialty ,Corneal Wavefront Aberration ,genetic structures ,medicine.medical_treatment ,Keratomileusis, Laser In Situ ,Visual Acuity ,Coma (optics) ,Keratomileusis ,Astigmatism ,Refraction, Ocular ,law.invention ,Cornea ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,law ,Ophthalmology ,medicine ,Small incision lenticule extraction ,Humans ,Postoperative Period ,Prospective Studies ,Keratometer ,business.industry ,LASIK ,Corneal Topography ,medicine.disease ,Centration ,eye diseases ,Sensory Systems ,Aberrations of the eye ,030221 ophthalmology & optometry ,Female ,Lasers, Excimer ,sense organs ,business ,030217 neurology & neurosurgery - Abstract
To determine the association between anterior corneal curvature and optical zone centration as well as its impact on aberration profiles in small-incision lenticule extraction (SMILE) and laser in situ keratomileusis (LASIK). Seventy-eight eyes of 78 patients treated with SMILE (45 eyes) and LASIK (33 eyes) were included. The centration of the optical zone was evaluated on the instantaneous curvature difference map between the preoperative and 3-month postoperative scans using a superimposed set of concentric circles. The correlation between optical zone decentration and anterior keratometry values was evaluated. The effect of optical zone decentration on vector components of astigmatic correction and induction of higher-order aberrations (HOA) was assessed. The mean decentration distance was 0.21 ± 0.11 mm for SMILE and 0.20 ± 0.09 mm for LASIK (p = 0.808). There was a significant correlation between anterior keratometric astigmatism and decentration distance (r = 0.653, p
- Published
- 2018
38. Review of rodent hypertensive glaucoma models
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Kelvin H Wan and Sayantan Biswas
- Subjects
Retinal Ganglion Cells ,medicine.medical_specialty ,genetic structures ,Glaucoma ,Neuroprotection ,Retinal ganglion ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Animal model ,Ophthalmology ,Medicine ,Animals ,Intraocular Pressure ,business.industry ,Retinal ,Optic Nerve ,General Medicine ,medicine.disease ,Short life ,eye diseases ,Pathophysiology ,Hypertonic saline ,Disease Models, Animal ,Neuroprotective Agents ,chemistry ,030221 ophthalmology & optometry ,sense organs ,business ,030217 neurology & neurosurgery - Abstract
Glaucoma is a neurodegenerative disease characterized by the progressive loss of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is a primary risk factor for the development and progression of glaucoma. Rodent models of glaucoma have greatly improved our understanding of the pathophysiology of glaucoma and served as a useful tool to investigate neuroprotective agents. An ideal glaucoma animal model should be easy to induce, reproducible, biologically plausible and predictable. Of the available animal models of glaucoma, rodents are commonly studied because they have a relatively short life span and can be genetically altered. A successful hypertensive glaucoma model should induce structural glaucomatous changes: including loss of retinal nerve fibres, retinal ganglion cells and optic-disc cupping along with IOP elevation. The level and duration of IOP elevation should be titratable depending on the targeted glaucomatous damage. This review summarizes the outcomes of induced rodent hypertensive glaucoma models including intracameral injection of microbeads, laser photocoagulation, episcleral vein cauterization, injection of hypertonic saline and hyaluronic acid. We aim to provide a detailed overview of each of the models with a focus on parameters that defines a successful glaucoma model. The induced IOP elevation and duration of elevation varied among the different models and strain of rodent; nonetheless, they all achieved a sustainable raised IOP with corresponding RGC loss. The limitations of each model are discussed.
- Published
- 2018
39. Longitudinal evaluation of posterior corneal changes after laser in situ keratomileusis in high myopia: a swept-source optical coherence tomography study
- Author
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Kelvin H, Wan, Tommy Cy, Chan, Marco, Yu, and Vishal, Jhanji
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Cornea ,Male ,Time Factors ,Keratomileusis, Laser In Situ ,Myopia ,Corneal Topography ,Humans ,Female ,Postoperative Period ,Tomography, Optical Coherence ,Follow-Up Studies - Published
- 2018
40. Impact of ocular residual astigmatism on predictability of myopic astigmatism correction after small-incision lenticule extraction
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Lin Zhang, Yan Wang, Tommy C Y Chan, and Kelvin H Wan
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Adult ,Male ,medicine.medical_specialty ,Corneal Surgery, Laser ,business.industry ,Corneal Stroma ,Visual Acuity ,Astigmatism ,Refraction, Ocular ,Residual ,medicine.disease ,Sensory Systems ,Myopic astigmatism ,Young Adult ,Ophthalmology ,Myopia ,Humans ,Medicine ,Small incision lenticule extraction ,Female ,Surgery ,Predictability ,business - Published
- 2019
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41. Efficacy and Safety of Topical 0.05% Cyclosporine Eye Drops in the Treatment of Dry Eye Syndrome: A Systematic Review and Meta-analysis
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Li Jia Chen, Kelvin H Wan, and Alvin L. Young
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medicine.medical_specialty ,Dose-Response Relationship, Drug ,business.industry ,Odds ratio ,Ophthalmology ,Treatment Outcome ,medicine.anatomical_structure ,Strictly standardized mean difference ,Meta-analysis ,Cornea ,Cyclosporine ,Humans ,Medicine ,Dry Eye Syndromes ,Ocular Surface Disease Index ,Ophthalmic Solutions ,Patient group ,Adverse effect ,business ,Fluorescence staining ,Immunosuppressive Agents - Abstract
A systematic review was performed to evaluate the safety and efficacy of topical 0.05% cyclosporine in treating patients with dry eye syndrome (DES). Twelve qualified randomized-controlled trials incorporating 1367 patients were analyzed. In comparison to controls, patients who were on topical 0.05% cyclosporine eye drops had lower Ocular Surface Disease Index scores (mean difference [MD]=4.10, 95% CI: 0.25-7.96, P=.04), longer tear film breakup time (MD=2.30 seconds, 95% CI: 0.75-3.86, P=.004), improved Schirmer I scores (MD=2.77 mm/5min, 95% CI: 1.63-3.91, P=.00001), reduced corneal fluorescein staining (standardized mean difference [SMD]=0.61, 95% CI: 0.07-1.15, P=.03), and higher goblet cell densities (SMD=1.68, 95% CI: 0.54-2.81, P=.004). However, there were more adverse effects in the cyclosporine patient group (odds ratio=1.64, 95% CI: 1.17-2.30, P=.004). Topical 0.05% cyclosporine eye drops twice daily significantly improved both the objective and subjective outcomes in DES patients. The study limitations in the clinical, methodological and statistical heterogeneities are discussed.
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- 2015
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42. Optical coherence tomography angiography in glaucoma: a mini-review
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Christopher Kai-Shun Leung and Kelvin H Wan
- Subjects
medicine.medical_specialty ,retina ,vascular abnormalities ,genetic structures ,Nerve fiber layer ,Glaucoma ,Review ,optical coherence tomography angiography ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,chemistry.chemical_compound ,optical imaging ,0302 clinical medicine ,Ophthalmology ,medicine ,General Pharmacology, Toxicology and Pharmaceutics ,Retina ,General Immunology and Microbiology ,business.industry ,Retinal ,optic nerve head ,General Medicine ,Blood flow ,Articles ,Inner plexiform layer ,medicine.disease ,eye diseases ,Ganglion ,medicine.anatomical_structure ,chemistry ,030221 ophthalmology & optometry ,Optic nerve ,Retinal, Vitreous & Macular Disorders ,sense organs ,business ,030217 neurology & neurosurgery - Abstract
The advent of optical coherence tomography angiography (OCT-A) provides a new opportunity to visualize the retinal vasculature in a non-invasive and dye-free manner which may help identify vascular abnormalities in glaucoma. While a reduction in retinal and optic nerve head vessel densities and blood flow indexes measured by OCT-A has been demonstrated in patients with glaucoma in many studies, it is unclear whether OCT-A provides additional information for the detection and monitoring of glaucoma compared with OCT measurements such as retinal nerve fiber layer thickness, neuroretinal rim width, and ganglion cell inner plexiform layer thickness. Longitudinal studies are needed to elucidate whether vascular abnormalities detected by OCT-A are a cause or a consequence of optic nerve damage in glaucoma.
- Published
- 2017
43. Preoperative optimization of ocular surface disease before cataract surgery
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Kelvin H Wan, Louis Tong, Jasmine Chuang, Vishal Jhanji, Tommy C Y Chan, and Kendrick Co Shih
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medicine.medical_specialty ,genetic structures ,medicine.medical_treatment ,Dry Eye Syndromes ,Intraocular lens ,Cataract Extraction ,law.invention ,Cornea ,03 medical and health sciences ,0302 clinical medicine ,Randomized controlled trial ,Lens Implantation, Intraocular ,law ,Ophthalmology ,medicine ,Humans ,Lenses, Intraocular ,Phacoemulsification ,Keratometer ,Ocular surface disease ,business.industry ,Cataract surgery ,Prognosis ,eye diseases ,Sensory Systems ,medicine.anatomical_structure ,030221 ophthalmology & optometry ,Surgery ,sense organs ,business ,030217 neurology & neurosurgery - Abstract
An impaired ocular surface adversely affects preoperative planning for cataract surgery, including intraocular lens (IOL) calculations, toric IOL axis and magnitude estimates, keratometry, and topography measurements. It also increases surgical difficulty. We performed a review to evaluate the connection between cataract surgery and dry eye and to determine the best management for these patients. Of the 16 papers included in this review, 6 were randomized controlled trials. Cataract surgery was shown to worsen ocular parameters and aggravate dry-eye disease. Physicians should recognize and aggressively treat cataract patients with poor prognostic factors and/or with existing dry-eye disease. Increased incision extent, operation time, irrigation, and microscopic-light exposure time decreased the tear breakup time and mean goblet cell density. Postoperatively, the use of eyedrops was associated with worsening of goblet cell density; hence, these medications should be tapered off when no longer needed.
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- 2017
44. Re: Hwang et al.: Distinguishing highly asymmetric keratoconus eyes using combined Scheimpflug and spectral-domain OCT analysis (Ophthalmology. 2018;125:1862-1871)
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Tommy C Y Chan and Kelvin H Wan
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Keratoconus ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Scheimpflug principle ,Corneal Topography ,Spectral domain ,Corneal topography ,medicine.disease ,Cornea ,Ophthalmology ,medicine.anatomical_structure ,medicine ,Humans ,business ,Tomography, Optical Coherence - Published
- 2019
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45. Topical Cyclosporine in the Treatment of Allergic Conjunctivitis
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Kelvin H Wan, Chi Pui Pang, Shi Song Rong, Alvin L. Young, and Li Jia Chen
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medicine.medical_specialty ,business.industry ,Odds ratio ,medicine.disease ,Placebo ,Confidence interval ,Allergic conjunctivitis ,law.invention ,Surgery ,Clinical trial ,Ophthalmology ,Randomized controlled trial ,law ,Strictly standardized mean difference ,Internal medicine ,Meta-analysis ,medicine ,business - Abstract
Purpose To assess the efficacy and safety of topical cyclosporine versus placebo in the treatment of allergic conjunctivitis. Design Systematic review and meta-analysis. Participants Seven qualified studies incorporating 306 eyes of 153 patients were analyzed. Methods Searches of randomized controlled trials were conducted in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. Main Outcome Measures We assessed the methodologic quality of individual included trials and performed meta-analyses using the random effects model if P Results At 2 weeks of follow-up or longer, evidence suggests a statistically significant improvement in the composite signs (standardized mean difference [SMD], −1.21; 95% confidence interval [CI], −1.80 to −0.62; I 2 = 71%) and symptoms (SMD, −0.84; 95% CI, −1.51 to −0.16; I 2 = 80%) after topical cyclosporine treatment for allergic conjunctivitis regardless of the dosage of treatment. There was a significant reduction (mean difference, −61.16; 95% CI, −101.61 to −20.72; I 2 = 58%) in the use of steroid eye drops in patients with steroid-dependent allergic conjunctivitis. Stinging or burning sensation (odds ratio, 2.56; 95% CI, 0.19–35.06; I 2 = 73%) was common in both the cyclosporine and placebo groups. Conclusions This systematic review and meta-analysis suggests topical cyclosporine could be an effective and safe treatment method for allergic conjunctivitis. Further randomized controlled trials with larger sample sizes and standardized outcome measurements, follow-up periods, and cyclosporine concentrations are warranted to determine the short- and long-term efficacy and safety and the minimal effective dosage of topical cyclosporine for allergic conjunctivitis. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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- 2013
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46. Depression and anxiety in dry eye disease: a systematic review and meta-analysis
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Kelvin H Wan, Alvin L. Young, and Li Jia Chen
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medicine.medical_specialty ,Neuro-ophthalmology ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,medicine ,Prevalence ,Eye Pain ,Humans ,Depression (differential diagnoses) ,Depressive Disorder ,business.industry ,Incidence (epidemiology) ,Case-control study ,Odds ratio ,Anxiety Disorders ,Surgery ,Ophthalmology ,Strictly standardized mean difference ,Meta-analysis ,Case-Control Studies ,030221 ophthalmology & optometry ,Clinical Study ,Anxiety ,Dry Eye Syndromes ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
AimTo evaluate the association of dry eye disease (DED) with depression and anxiety.Patients and methodsWe conducted a systematic review and meta-analysis of studies that reported the prevalence, incidence and/or severity grading of depression and/or anxiety in DED patients and healthy controls. We searched MEDLINE, EMBASE, PsycINFO, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform for relevant studies.ResultsTwenty-two eligible studies consisted of 2 980 026 patients were analyzed. DED was associated with an increased prevalence of depression (summary odds ratio (OR)=2.92, 95% CI: 2.13-4.01, P0.00001) and anxiety (OR=2.80, 95% CI: 2.61-3.02, P0.00001). The depression score (standardized mean difference (SMD)=0.81, 95% CI: 0.48-1.15, P0.00001) and anxiety score (SMD=0.37, 95% CI: 0.10-0.64, P=0.007) were higher in DED patients than in controls. Subgroup analyses revealed that the prevalence and severity of depression are greatest in primary Sjogren's syndrome patients. No study reported the incidence.ConclusionDepression and anxiety are more prevalent in DED patients than in controls. Among patients with DED, those suffering from primary Sjogren's syndrome have higher prevalence and severity of depression.
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- 2016
47. Optical Coherence Tomography Angiography Compared With Optical Coherence Tomography Macular Measurements for Detection of Glaucoma
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Christopher Kai-Shun Leung, Kelvin H Wan, and Alexander Lam
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Adult ,Male ,Retinal Ganglion Cells ,0301 basic medicine ,medicine.medical_specialty ,genetic structures ,Gonioscopy ,Visual Acuity ,Glaucoma ,Retina ,03 medical and health sciences ,chemistry.chemical_compound ,Nerve Fibers ,0302 clinical medicine ,Optical coherence tomography ,Ophthalmology ,medicine ,Humans ,Fluorescein Angiography ,Intraocular Pressure ,Aged ,Original Investigation ,Receiver operating characteristic ,medicine.diagnostic_test ,business.industry ,Internal limiting membrane ,Retinal Vessels ,Retinal ,Organ Size ,Optical coherence tomography angiography ,Middle Aged ,medicine.disease ,Inner plexiform layer ,eye diseases ,Cross-Sectional Studies ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Area Under Curve ,030221 ophthalmology & optometry ,Visual Field Tests ,Female ,sense organs ,Visual Fields ,business ,Glaucoma, Open-Angle ,Tomography, Optical Coherence - Abstract
IMPORTANCE: Whether optical coherence tomography angiography (OCT-A) outperforms OCT to detect glaucoma remains inconclusive. OBJECTIVE: To compare (1) the diagnostic performance for detection of glaucoma and (2) the structure-function association between inner macular vessel density and inner macular thickness. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study included 115 patients with glaucoma and 35 healthy individuals for measurements of retinal thickness and retinal vessel density, segmented between the anterior boundary of internal limiting membrane and the posterior boundary of the inner plexiform layer, over the 3 × 3-mm(2) macula using swept-source OCT. All participants were Chinese. Visual sensitivity corresponding to the 3 × 3-mm(2) macular region was expressed in unlogged 1/lambert for investigation of the structure-function associations. Diagnostic performance was evaluated with area under the receiver operating characteristic curves (AUCs). The study was conducted between January 12, 2016, and December 12, 2016. MAIN OUTCOMES AND MEASURES: Area under the receiver operating characteristic curve and R(2) analysis. RESULTS: Of the 115 patients with glaucoma, 42 (36.5%) were women (mean [SD] age, 53.5 [13.4] years); of the 35 individuals with healthy eyes, 25 (71.4%) were women (age, 60.6 [5.9] years). Inner macular vessel density and thickness were 4.3% (95% CI, 2.4%-6.1%) and 21.1 μm (95% CI, 17.4-24.9 μm) smaller, respectively, in eyes with glaucoma compared with healthy eyes. The AUC of mean inner macular thickness for glaucoma detection was greater than that of mean inner macular vessel density (difference, 0.17; 95% CI, 0.01-0.31; P = .03). At 90% specificity, the sensitivity of mean inner macular thicknesses for detection of glaucoma was greater than that of mean inner macular vessel densities (difference, 29.2%; 95% CI, 11.5%-64.6%; P = .02). The strength of the structure-function association was stronger for mean inner macular thickness than mean inner macular vessel density in the linear (difference in R(2) = 0.38; 95% CI, 0.22-0.54; P
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- 2018
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48. Efficacy of Combined Retisert and Ahmed Glaucoma Valve for Medically Uncontrolled Uveitis and Glaucoma
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Kelvin H Wan and Dennis S.C. Lam
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Intraocular pressure ,medicine.medical_specialty ,Treatment outcome ,Glaucoma ,Glaucoma valve ,Uveitis ,03 medical and health sciences ,0302 clinical medicine ,Fluocinolone acetonide ,Ophthalmology ,medicine ,Humans ,Glaucoma Drainage Implants ,Intraocular Pressure ,Glaucoma drainage implant ,business.industry ,medicine.disease ,Treatment Outcome ,Fluocinolone Acetonide ,030221 ophthalmology & optometry ,business ,030217 neurology & neurosurgery ,medicine.drug - Published
- 2017
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49. Endophthalmitis After Intravitreal Injections in Patients With Self-reported Iodine Allergy
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Kelvin H Wan, Dennis S.C. Lam, and Nishant Radke
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Endophthalmitis ,medicine.medical_specialty ,business.industry ,medicine.disease ,Iodine allergy ,Dermatology ,Eye Infections, Bacterial ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Ophthalmology ,0302 clinical medicine ,Intravitreal Injections ,Hypersensitivity ,030221 ophthalmology & optometry ,medicine ,Humans ,In patient ,Self Report ,business ,Iodine - Published
- 2017
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50. Corneal transplantation: Beyond the horizon
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Evan Po-Fat Yiu, Kelvin H Wan, and Alvin L. Young
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medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Ophthalmology ,Medicine ,business ,Corneal transplantation - Published
- 2015
- Full Text
- View/download PDF
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