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Introduction: The study aimed to compare postoperative pain between alcohol-assisted and transepithelial photorefractive keratectomy in patients who received the novel analgesic preoperative nepafenac treatment 2 days preoperatively and 3 days postoperatively. Pain, stinging, tearing, light sensitivity, and stress levels were evaluated. Methods: The study included a retrospective analysis of 55 patients divided into two groups: bilateral alcohol-assisted photorefractive keratectomy (aa-PRK) and transepithelial photorefractive keratectomy (transepithelial-PRK). Nepafenac was administered for pain control for all patients, with patients receiving four drops for 2 days before the surgery and 3 days postoperatively per clinical instructions. Patients completed questionnaires on the day of the surgery and for the first 5 days postoperatively. Statistical analysis was performed using XLSTAT (version 2023.1.2). t-Test was used to analyze and compare pain and symptom levels and Fisher's exact test for categorical data. p-Values less than 0.05 were considered statistically significant. Results: The study examined 55 patients (49% female) with a mean age of 25.11 ± 6.81 years who had undergone bilateral surface refractive surgery to correct myopic errors. The mean baseline standard error (SE) was −3.16 ± 2.20 D. Among these patients, 27 patients underwent aa-PRK and 28 patients underwent transepithelial-PRK. Higher levels of pain were significant in the aa-PRK group (p = 0.003). However, there was no significant difference between the groups in the average levels of stinging, tearing, or light sensation. Additionally, stress levels decreased over time in both groups, with levels becoming almost equal after 5 days, and there was no significant difference in the average stress levels between the two groups. Conclusions: The study found that patients who underwent the transepithelial-PRK procedure had significantly lower pain levels compared with those who underwent aa-PRK after being treated with nepafenac per protocol. However, there was no significant difference between the two groups in terms of stinging, tearing, light sensation, and stress levels. [ABSTRACT FROM AUTHOR]

With the continuous development of refractive surgery and the continuous innovation of related technologies in recent years, postoperative complications such as dry eye and corneal nerve damage have received increased attention. At the moment, corneal nerve damage after refractive surgery and related drugs to promote repair are a hot topic. The purpose of this article is to review the research progress in the repair of dry eye and postoperative nerve injury after laser in situ keratomileusis (LASIK), to further explore the way to promote corneal nerve repair, reduce postoperative complications, improve corneal refractive surgery, and achieve the best long-term visual effect. [ABSTRACT FROM AUTHOR]

Background: To report the refractive outcomes of StreamLight transepithelial photorefractive keratectomy (PRK). Methods: A retrospective case series was conducted which included a total of 205 eyes of 109 patients who underwent StreamLight transepithelial PRK using the Alcon Wavelight EX500 excimer laser. All eyes had myopia or myopic astigmatism, and the preoperative spherical equivalent (SEQ) ranged from −0.63D to −7.25D. The primary postoperative outcomes were UDVA, CDVA and subjective refraction measured at least 3 months postoperatively. Results: Postoperatively, 196 eyes (95.6%) had a UDVA of 20/20 or better. The mean SEQ was −0.05 ± 0.31D and 189 eyes (92.2%) were within ±0.50D of the target SEQ. The mean refractive astigmatism was −0.28 ± 0.27D, and 181 eyes (88.3%) had ≤ 0.50D of astigmatism. The mean safety and efficacy indices were 1.01 ± 0.08 and 0.97 ± 0.12, respectively. Eight eyes lost 1 line of CDVA. Six of these were noted to have significant dry eyes and 2 had corneal haze. No eye lost two or more lines of CDVA. Conclusions: StreamLight transepithelial PRK results in excellent refractive outcomes for myopia and myopic astigmatism. [ABSTRACT FROM AUTHOR]

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Laser assisted in situ keratomileusis (LASIK) surgery is the leading and most performed refractive surgery nowadays. A possible complication of LASIK surgery is infectious keratitis which can lead to disastrous corneal damage and result in permanent loss of vision. LASIK procedures have become increasingly accessible, and the demand for refractive surgery has risen among patients, challenging the medical field to improve the prevention of post-operative infections. Nevertheless, a wide range of pathogens have been described as responsible for post-LASIK keratitis. However, non-tuberculous mycobacterial keratitis remains an infrequent occurrence and is poorly described in the literature. To the best of our knowledge, this is the first ever reported case of post-LASIK keratitis caused by Mycobacterium wolinskyi. We describe the clinical and microbial characteristics, leading to its challenging treatment choice. [ABSTRACT FROM AUTHOR]

To investigate the visual outcomes and patient satisfaction following trifocal intraocular lens (IOL) implantation after radial keratotomy (RK). Methods: This was a retrospective chart review wherein we studied 14 eyes from 7 patients who had undergone cataract surgery and had trifocal intraocular lens (IOL) implanted in the Eastern Province of Saudi Arabia's King Fahd University Hospital and Kahhal private centre. Data such as demographic characteristics, the time between RK and cataract removal, intraoperative and postoperative complications, preoperative and postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and refraction were evaluated. In addition, visual complaints and satisfaction were assessed through a questionnaire. Results: All eyes included had 8 RK sections. The mean spherical equivalent was +1.81 ± 4.27 D preoperatively and was − 0.41 ± 1.2 D at the last follow-up. The mean uncorrected distance visual acuity (UDVA) increased from 0.32 ± 0.2 prior to surgery to 0.64 ± 0.2 following surgery. The mean efficacy index was 1.01 and a safety index was 1.26. In the last follow-up, 29% reported having 0.5 spherical equivalents, while 86% were within 1D. Improvement in cylindrical correction was noticed in the last follow-up with 36% not more than 0.5 D and 43% within 1D. In total, 80% of patients had a distance-corrected near visual acuity (DCNVA) of better than 20/40. The survey response rate was 100%, and two patients reported a lower degree of satisfaction. Glare and difficulty seeing at night were the most often reported complaints, with a mean of 2.86 ± 1.95 and 22 ± 1.9, respectively. Conclusion: Our results suggest that implantation of a trifocal IOL is safe and effective in patients with previous RK. However, several factors, including the patient's preoperative expectations, glare testing, refractive error, number of cuts, optical zone size, and visual phenomena related to RK, should be considered before implantation. [ABSTRACT FROM AUTHOR]

Background: Single-step transepithelial photorefractive keratectomy (TPRK) is a modern refractive surgery technique that offers a no-touch approach for correcting myopia and astigmatism. This study aims to evaluate the short-term visual and refractive outcomes of TPRK in patients with myopia and astigmatism over a 6-month follow-up period. Methods: This retrospective cohort study included patients who underwent single-step TPRK using the Amaris 750S laser platform with SmartSurfACE and SmartPulse® technologies, targeting a plano refraction. Procedures were performed with aspheric, non-wavefront-guided profiles, and outcomes were assessed postoperatively. Results: 96% of eyes achieved 20/20 or better uncorrected distance visual acuity (UDVA), with 98% reaching 20/25 or better, and 100% achieving 20/32 or better. UDVA was the same or better than preoperative corrected distance visual acuity (CDVA) in 96% of eyes, and no eyes lost two or more Snellen lines. Refractive outcomes showed strong precision, with 93% of eyes within ±1.00 D of the target. Astigmatism correction was accurate, with 100% of eyes having ≤1.00 D of astigmatism, and 80% achieving a precise astigmatism angle of error between −5° and 5°. Conclusion: Single-step TPRK with SmartSurfACE and SmartPulse® technologies provides highly effective and predictable visual and refractive outcomes for myopia and astigmatism. The procedure consistently delivers precise corrections with minimal complications, making it a reliable option for refractive surgery. [ABSTRACT FROM AUTHOR]

AIM: To evaluate the clinical outcomes after subsequent implantation of a new intrastromal corneal ring segment (ICRS) model followed by an additional short-arc ICRS implant in keratoconus patients. METHODS: This retrospective single-arm cohort study evaluated 25 eyes of 21 keratoconus patients implanted with the new ICRS followed by 140-arch length ICRS (140-ICRS) implantation. Uncorrected distance visual acuity (UDVA, logMAR), corrected distance visual acuity (CDVA, logMAR), sphere, astigmatism, keratometry, spherical equivalent (SE), and asphericity were compared preoperatively and postoperatively after both ICRS implantation. RESULTS: The average follow-up time after 140-ICRS implantation was 6.40±2.20mo. The mean preoperative UDVA improved from 1.27±0.14 preoperative to 0.52±0.26 after both ICRS implantation (P=0.03). The mean sphere value reduced from -5.34±2.74 preoperatively to -2.06±1.84 postoperatively (P

Abstract Introduction The study aimed to compare postoperative pain between alcohol-assisted and transepithelial photorefractive keratectomy in patients who received the novel analgesic preoperative nepafenac treatment 2 days preoperatively and 3 days postoperatively. Pain, stinging, tearing, light sensitivity, and stress levels were evaluated. Methods The study included a retrospective analysis of 55 patients divided into two groups: bilateral alcohol-assisted photorefractive keratectomy (aa-PRK) and transepithelial photorefractive keratectomy (transepithelial-PRK). Nepafenac was administered for pain control for all patients, with patients receiving four drops for 2 days before the surgery and 3 days postoperatively per clinical instructions. Patients completed questionnaires on the day of the surgery and for the first 5 days postoperatively. Statistical analysis was performed using XLSTAT (version 2023.1.2). t-Test was used to analyze and compare pain and symptom levels and Fisher’s exact test for categorical data. p-Values less than 0.05 were considered statistically significant. Results The study examined 55 patients (49% female) with a mean age of 25.11 ± 6.81 years who had undergone bilateral surface refractive surgery to correct myopic errors. The mean baseline standard error (SE) was −3.16 ± 2.20 D. Among these patients, 27 patients underwent aa-PRK and 28 patients underwent transepithelial-PRK. Higher levels of pain were significant in the aa-PRK group (p = 0.003). However, there was no significant difference between the groups in the average levels of stinging, tearing, or light sensation. Additionally, stress levels decreased over time in both groups, with levels becoming almost equal after 5 days, and there was no significant difference in the average stress levels between the two groups. Conclusions The study found that patients who underwent the transepithelial-PRK procedure had significantly lower pain levels compared with those who underwent aa-PRK after being treated with nepafenac per protocol. However, there was no significant difference between the two groups in terms of stinging, tearing, light sensation, and stress levels.

PURPOSE The purpose of this study was to compare early visual outcomes, epithelial healing, and stromal haze between transepithelial photorefractive keratectomy (Trans-PRK) using smart pulse technology (SPT) with traditional Trans-PRK. METHODOLOGY This study is a retrospective, comparative study conducted at a private eye center in “Riyadh, Saudi Arabia,” investigating myopic patients who underwent either Trans-PRK with SPT (study group) or traditional Trans-PRK (control group). The patients were assessed preoperatively and followed up at 1 week and 2 months postoperatively. The main outcomes included uncorrected distance visual acuity (UDVA), corneal haze, and corneal epithelial defect. RESULTS This study included 501 eyes, of them, 222 eyes (44.3%) underwent Trans-PRK with SPT. The UDVA in the study group was significantly better 1 week postoperatively (P < 0.05). For the 2-month follow-up visits, there was no significant difference between the groups. Epithelium healing and stromal haze were comparable in the two groups without significant differences between them. CONCLUSION Transepithelial photorefractive keratectomy with SPT yielded better short-term visual outcomes than traditional Transepithelial photorefractive keratectomy.

Abstract Laser assisted in situ keratomileusis (LASIK) surgery is the leading and most performed refractive surgery nowadays. A possible complication of LASIK surgery is infectious keratitis which can lead to disastrous corneal damage and result in permanent loss of vision. LASIK procedures have become increasingly accessible, and the demand for refractive surgery has risen among patients, challenging the medical field to improve the prevention of post-operative infections. Nevertheless, a wide range of pathogens have been described as responsible for post-LASIK keratitis. However, non-tuberculous mycobacterial keratitis remains an infrequent occurrence and is poorly described in the literature. To the best of our knowledge, this is the first ever reported case of post-LASIK keratitis caused by Mycobacterium wolinskyi. We describe the clinical and microbial characteristics, leading to its challenging treatment choice.

AIM:To investigate the clinical efficacy of phakic implantable collamer lens(ICL)implantation in correcting low-to-moderate myopia.METHODS: Retrospective study. A total of 48 patients(85 eyes)with low to moderate myopia who underwent ICL implantation were included in the study. The changes in uncorrected visual acuity(LogMAR), corrected visual acuity(LogMAR), refractive outcomes, intraocular pressure, vault and endothelial cell were observed at 1 a postoperatively.RESULTS: At 12 mo postoperatively, uncorrected and best-corrected visual acuity were -0.10(-0.20, -0.10)and -0.10(-0.20, -0.10), respectively, with an efficacy index of 1.07±0.13 and a safe index of 1.10±0.14. The difference between the actual corrected diopter and the expected corrected diopter was 91%(77/85)in the range of ±0.50 D, and 100%(85/85)in the range of ±1.00 D. The mean vault was 501.16±210.46 μm at 12 mo postoperatively. There was no significant difference in corneal endothelial cell density between preoperative and 6 and 12 mo postoperatively(F=1.050, P=0.352). All patients had no anterior subcapsular opacification, cataract, pupillary block, or other sight threatening complications during follow-up.CONCLUSION: ICL implantation for the correction of low to moderate myopia has good efficacy, safety and predictability.

The cornea is one of the tissues responsible for covering and protecting the inner structures of the eye. Central corneal thickness (CCT) is defined as the distance between the anterior epithelial surface and the posterior surface of the endothelial layer. This parameter plays a very important role regarding intraocular pressure (IOP) measurement, evaluation of corneal uniformity, selection of a suitable technique for corneal refractive surgery and the planning of surgical procedures to overcome corneal disease. This comprehensive review elucidates the multifaceted factors influencing the central corneal thickness. Recognising the impact of these factors not only enhances our understanding of corneal dynamics but also contributes significantly to the refinement of diagnostic and therapeutic strategies in ophthalmology. [ABSTRACT FROM AUTHOR]

Abstract Background Implantable Collamer Lense (ICL) presents a viable alternative to conventional refractive surgeries, but their impact on corneal microstructure remains unclear. By employing in vivo confocal microscopy (IVCM), we examined changes in stromal and endothelial cells following the insertion of V4c ICLs, with the goal of enhancing post-surgical care and outcomes. Methods In this longitudinal investigation, we conducted detailed preoperative assessments on 103 eyes from 53 participants. Follow-up evaluations were carried out after surgery at set intervals: one day, one week, one month, three months, six months, and twelve months. We used IVCM to analyze changes in stromal and endothelial cells. To assess differences between pre- and post-surgery variables and to investigate correlations with age, axial length (AL), and spherical equivalent refraction (SER), we applied a repeated measures mixed-effects model, with statistical significance set at P

Abstract Background To evaluate clinical outcomes and visual quality 3 months after mini-monovision (spherical equivalent [SE] between − 0.25 D and − 0.50 D) femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for correction of high myopia in patients with presbyopia. Methods Patients who had mini-monovision FS-LASIK for high myopia (SE < -6.0 D) and aged between 40 and 50 years were included. At the 3-month postoperative visit, we evaluated full range of visual acuity; defocus curve; optical quality; accommodation function, contrast sensitivity and stereopsis. Binocular tests were done twice, once in mini-monovision condition and once with the residual myopia in the non-dominant eye corrected. Subjective visual quality was evaluated with questionnaire postoperatively with mini-monovision correction. Results Clinical data of 31 cases were analyzed. The average patient age was 42.58 ± 3.06 years. At the 3-month follow-up, the mean uncorrected binocular visual acuity at distance, intermediate, and near was − 0.11 ± 0.07, -0.06 ± 0.10, and 0.04 ± 0.11 logMAR separately. In comparison, patients with binocular full distance correction achieved better uncorrected distance visual acuity (UDVA), and they achieved superior uncorrected near visual acuity (UNVA, P = 0.04) with mini-monovision correction. FS-LASIK induced significant increases in higher-order aberrations (HOAs) (P

Abstract Background To explore intraocular lens (IOL) preferences of United Kingdom-based (UK) refractive surgeons in cataract and refractive lens exchange (RLE) surgery. Methods An online survey on IOL preferences (and reasons for their choice) in cataract and RLE surgery was distributed. It also enquired about implementing mini-monovision with extended depth of field (EDoF) IOLs, about utilising IOL mix-and-match (different IOL types in each eye), and at what level of corneal astigmatism they prefer toric lenses. Results Following an 81.6% response rate, thirty responses were analysed; median years of refractive surgery experience was 12.5. The most popular IOL choices for cataract surgery were EDoF lenses (30%), monofocals (20%), and trifocals (20%). The most cited reason for each was better overall visual outcomes (88.9%), fewer unwanted symptoms (66.7%) and best spectacle independence (66.7%), respectively. For RLE, EDoF remained most popular (36.7%), followed by trifocals (30%), and multifocals (16.7%) with the same reasons for choice cited above. Mini-monovision with EDoF lenses was well-regarded (83% recommend for most/select patients), unlike utilising IOL mix-and-match (60% did not recommend). 40% prefer toric IOLs for astigmatism of 1 dioptre (D) or higher, whilst 30% opt for them at

Purpose: To analyze the United States Food and Drug Administration’s Manufacturer and User Facility Device Experience (MAUDE) database, which contains reports of adverse events involving medical devices, and characterize the most common adverse events of femtosecond (FS) laser-assisted in situ keratomileusis (LASIK). Methods: The MAUDE database was queried on May 19, 2022, for adverse events involving the ophthalmic FS laser reported from January 2012 to April 2022. Reports unrelated to LASIK procedures were excluded. Data extraction was performed on these reports, including the type of adverse event and whether surgery was successfully completed. Frequency analysis was performed using the Statistical Package for the Social Sciences. Results: From the 3491 reported adverse events involving the FS laser system, 1136 met the inclusion criteria. Of the 672 cases where outcomes were reported, 476 were successfully completed and 196 were aborted. The most common intraoperative complications were incomplete cut (42.8%), thinner than intended flap (17.6%), and difficulty lifting the flap (12.0%). FS-related complications included opaque bubble layer (2.3%), air bubbles in the anterior chamber (2.4%), and vertical gas breakthrough (4.1%). Other device-related intraoperative complications included suction loss (10.2%), difficulty docking (2.4%), and laser malfunction (2.0%). The most common postoperative complications were diffuse lamellar keratitis (DLK) (7.8%) and rainbow glare (4.6%). Conclusion: The most common intraoperative FS-assisted LASIK complication in the MAUDE database was an incomplete flap. The most common postoperative complication was DLK. This study is the first to investigate FS-assisted LASIK adverse events in the MAUDE database. It can raise awareness of real-world surgical complications and help ophthalmologists better counsel and treat patients.

The global surge in refractive surgeries, particularly among myopic individuals, has elicited concerns regarding potential inaccuracies in the measurement of intraocular pressure (IOP) post surgery, primarily associated with central corneal thinning. The incidence of elevated IOP after intraocular refractive surgeries is higher than expected and is multifactorial. Myopic eyes have a higher susceptibility to both primary and secondary glaucoma. Consequently, meticulous preoperative screening for glaucoma is imperative, coupled with systematic postoperative follow-up and evaluation. This comprehensive review analyses the etiology, mechanisms, and therapeutic strategies for managing elevated IOP following refractive surgery. We propose an algorithm to summarize the causative factors of elevated IOP and formulate effective interventions in these instances.

Abstract Purpose To investigate the three-year visual, refractive outcomes and adverse events of the Eyecryl toric phakic IOL (pIOL) for moderate-to-high myopic astigmatism. Methods This retrospective study included eligible patients who underwent refractive surgery in one or both eyes with Eyecryl toric pIOL for myopic astigmatism. The efficacy, safety, predictability, rotational stability, vector analysis, and adverse events were evaluated in patients with spherical refraction from − 4.50 to -17.00 diopters (D) and cylindrical refraction from − 0.75 to -5.50 D. Results Fifty-two eyes of 28 patients were included in the study. The mean efficacy and safety index were 1.12 ± 0.35 and 1.38 ± 0.42, respectively. The mean manifest refraction spherical equivalent was − 10.06 ± 2.69 D and − 0.64 ± 0.61 D preoperatively and postoperatively at 36 months, respectively. The mean manifest astigmatism was − 2.06 ± 1.16 D and − 0.44 ± 0.48 D preoperatively and 36 months postoperative, respectively. During the final examination, 70% of the eyes showed an increase in CDVA of one or more lines compared to their preoperative state. There was a cumulative endothelial cell loss of 3.1% at 36 months postoperatively. One eye developed visually significant anterior subcapsular opacity, whereas another eye experienced pIOL opacification. Conclusion The Eyecryl toric pIOL demonstrated satisfactory visual acuity and refractive outcomes, as assessed by efficacy, safety and stability over a three-year period.

Abstract The objective of this study was to investigate the culture positivity and distribution of the conjunctival sac bacteria in the perioperative period of corneal refractive surgery. The selected time points of the perioperative period included before the use of antibiotic eye drops, before eye wash (after the use of antibiotic eye drops), after eye wash, and immediately after surgery. Conjunctival specimens obtained at the four time points were cultured to detect the positivity and distribution of bacteria. Before prophylactic antibiotic eye drops were administered, 49 eyes (50%) had positive bacterial culture results, with 45 isolates (91.8%) identified as Staphylococcus epidermidis. The culture positivity rates of the conjunctival sac specimens before eye wash, after eye wash, and immediately after surgery were 19.4%, 3.1%, and 4.1%, respectively. The difference was significant before and after the use of antibiotics and before and after eye wash (both P 0.05). The judicious preoperative use of antibiotic eye drops combined with the surgical sterile eye wash procedure maximised the removal of conjunctival sac bacteria. Skilled surgical manipulations generally did not increase the risk of infection.

Abstract Background To compare the repeatability and reproducibility of corneal and corneal epithelial thickness mapping using anterior segment optical coherence tomography (AS-OCT) according to tear film break-up time (TBUT). Methods The included eyes were divided into three subgroups according to TBUT (group 1: TBUT ≤ 5 s, group 2: 5 s 10 s). All eyes were imaged separately thrice by two operators to obtain the thickness maps (TMs) of the cornea and corneal epithelium based on spatial zones encompassing a 9-mm-diameter area. Each TM consisted of 25 areas. Intraoperator (repeatability) and interoperator (reproducibility) standard deviations (Sws), coefficients of variation (CoVs), and intraclass correlation coefficients (ICCs) among the tests were calculated and compared in all the areas. Results Altogether, 132 eyes of 67 subjects were included (50, 47, and 35 eyes in groups 1, 2, and 3; respectively). The ICCs of corneal epithelial thickness and corneal thickness were > 0.75 in most of the areas. Pairwise comparisons showed that AS-OCT exhibited lower repeatability in group 1 than in groups 2 and 3 (P

Advances in imaging technology have revolutionized the field of ophthalmology, changing the understanding, diagnosis, and treatment of ophthalmic diseases. Swept-source optical coherence tomography(SS-OCT)is a non-contact high-resolution imaging technology. It further improves imaging depth and scanning speed, adds new algorithms and features. The application of SS-OCT enables the three-dimensional evaluation of corneal structures, offering curvature and height maps for both the anterior and posterior surfaces of the cornea, as well as precise corneal thickness mapping. These invaluable tools aid ophthalmologists in effectively screening and diagnosing various corneal lesions such as keratoconus, corneal dystrophy, and degeneration. Moreover, the enhanced speed, accuracy, and sensitivity provided by SS-OCT measurements facilitate improved surgical planning and postoperative monitoring for patients undergoing refractive surgery or keratoplasty. This article reviews the development of SS-OCT technology and its potential clinical utility in corneal diseases and surgical application, in order to support more possible future research and clinical treatment.

Purpose To report the impact of front surface eccentricity (FSE) of scleral lenses (SCLs) on the visual performance of eyes exhibiting refractive surgery-induced higher-order aberrations (HOAs) Method A female teenager presented to the clinic with blurring of vision and dependency on spectacles even after undergoing Small Incision Lenticule Extraction (SMILE) in both eyes (BE). Her presenting uncorrected high contrast distance visual acuity (HCDVA) was 20/60 in the right eye (RE) and 20/40 in the left eye (LE). On examination, the cornea showed a ring-shaped area of ablation with faint scarring and a well-apposed lenticule-extraction site. Subjective refraction improved the HCDVA to 20/20p in RE and 20/25 in LE but the patient was not happy with the quality of vision. Ocular aberrometry revealed an increase in total HOAs as the underlying cause of unsatisfactory vision. Result A contact lens trial was recommended for BE to enhance visual quality. Rigid corneal lenses (RCLs) were tried, but the patient was intolerant to them. Large diameter SCLs of different FSEs (0, 0.6, and 0.8) were tried to reduce these aberrations. SCL with FSE 0 yielded the most favourable visual outcome, which was confirmed subjectively on ocular aberrometry. Conclusion With this case report, we hypothesize that the eccentricity of SCL can be selected according to the asphericity (at 6 mm) of the posterior corneal surface. This case also re-emphasizes the impact of SCL with varying FSEs on reducing HOAs and enhancing visual quality in eyes where conventional RCLs yield suboptimal results.

Background: To evaluate clinical outcomes and visual quality 3 months after mini-monovision (spherical equivalent [SE] between − 0.25 D and − 0.50 D) femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for correction of high myopia in patients with presbyopia. Methods: Patients who had mini-monovision FS-LASIK for high myopia (SE < -6.0 D) and aged between 40 and 50 years were included. At the 3-month postoperative visit, we evaluated full range of visual acuity; defocus curve; optical quality; accommodation function, contrast sensitivity and stereopsis. Binocular tests were done twice, once in mini-monovision condition and once with the residual myopia in the non-dominant eye corrected. Subjective visual quality was evaluated with questionnaire postoperatively with mini-monovision correction. Results: Clinical data of 31 cases were analyzed. The average patient age was 42.58 ± 3.06 years. At the 3-month follow-up, the mean uncorrected binocular visual acuity at distance, intermediate, and near was − 0.11 ± 0.07, -0.06 ± 0.10, and 0.04 ± 0.11 logMAR separately. In comparison, patients with binocular full distance correction achieved better uncorrected distance visual acuity (UDVA), and they achieved superior uncorrected near visual acuity (UNVA, P = 0.04) with mini-monovision correction. FS-LASIK induced significant increases in higher-order aberrations (HOAs) (P < 0.001). For accommodative function, only the negative relative accommodation (NRA) improved significantly after surgery (P < 0.001). A slight decrease in contrast sensitivity was observed at low spatial frequency with mini-monovision correction (P < 0.05). Questionnaire demonstrated high satisfaction with near vision and visual quality. Conclusion: FS-LASIK with mini-monovision (SE between − 0.25 D and − 0.50 D) appeared to be safe and effective in treating high myopia combined with presbyopia to get satisfying visual quality at distant and at near. [ABSTRACT FROM AUTHOR]

Background: Implantable Collamer Lense (ICL) presents a viable alternative to conventional refractive surgeries, but their impact on corneal microstructure remains unclear. By employing in vivo confocal microscopy (IVCM), we examined changes in stromal and endothelial cells following the insertion of V4c ICLs, with the goal of enhancing post-surgical care and outcomes. Methods: In this longitudinal investigation, we conducted detailed preoperative assessments on 103 eyes from 53 participants. Follow-up evaluations were carried out after surgery at set intervals: one day, one week, one month, three months, six months, and twelve months. We used IVCM to analyze changes in stromal and endothelial cells. To assess differences between pre- and post-surgery variables and to investigate correlations with age, axial length (AL), and spherical equivalent refraction (SER), we applied a repeated measures mixed-effects model, with statistical significance set at P < 0.05. Results: No vision-threatening complications were reported post-surgery. Significant reductions in stromal cell density (SCD) were observed postoperatively, with anterior and mid- SCD reaching their lowest values at 3 months and posterior SCD at 1 month, remaining below baseline at 12 months. endothelial cell density (ECD) and percentage of hexagonal cells (PHC) decreased initially, recovering by 12 months. Conversely, endothelial cellular area (ECA) and coefficient of variation of cell size (CoV) increased postoperatively, with the most significant change at 1 week. Endothelial deposits were detected in 49 of 101 eyes on postoperative day 1, half of them were absorbed within 3 months post-surgery. Changes in posterior SCD were negatively related to AL, while AL, SER, lens thickness showed associated with endothelium changes. Conclusion: Our findings elucidate the corneal microstructural changes following V4c ICL implantation, particularly the significant early reductions in stromal and endothelial cell densities. We recommend careful management of viscoelastics during surgery to minimize endothelial deposits that may harm the endothelium. Enhanced early postoperative monitoring and these surgical adjustments can lead to improved surgical and post-surgical care, ultimately supporting better patient recovery. [ABSTRACT FROM AUTHOR]

Background/Objectives: This study aims to identify the most accurate regression model for predicting total corneal astigmatism (TCA) from anterior corneal astigmatism (ACA) and to fine-tune the best model's architecture to further optimize predictive accuracy. Methods: A retrospective review of 19,468 eyes screened for refractive surgery was conducted using electronic medical records. Corneal topography data were acquired using the Pentacam HR. Various types (7) and subtypes (21) of regression learners were tested, with a deep neural network (DNN) emerging as the most suitable. The DNN was further refined, experimenting with 23 different architectures. Model performance was evaluated using root mean squared error (RMSE), R2, average residual error, and circular error. The final model only used age, ACA magnitude, and ACA axis to predict TCA magnitude and axis. Results were compared to predictions from one of the leading TCA prediction formulas. Results: Our model achieved higher performance for TCA magnitude prediction (R2 = 0.9740, RMSE = 0.0963 D, and average residual error = 0.0733 D) compared to the leading formula (R2 = 0.8590, RMSE = 0.2257 D, and average residual error = 0.1928 D). Axis prediction error also improved by an average of 8.1° (average axis prediction error = 4.74° versus 12.8°). The deep learning approach consistently demonstrated smaller errors and tighter clustering around actual values compared to the traditional formula. Conclusion: Deep learning techniques significantly outperformed traditional methods for TCA prediction accuracy using the Pentacam HR. This approach may lead to more precise TCA calculations and better IOL selection, potentially enhancing surgical outcomes. [ABSTRACT FROM AUTHOR]

Background: To explore intraocular lens (IOL) preferences of United Kingdom-based (UK) refractive surgeons in cataract and refractive lens exchange (RLE) surgery. Methods: An online survey on IOL preferences (and reasons for their choice) in cataract and RLE surgery was distributed. It also enquired about implementing mini-monovision with extended depth of field (EDoF) IOLs, about utilising IOL mix-and-match (different IOL types in each eye), and at what level of corneal astigmatism they prefer toric lenses. Results: Following an 81.6% response rate, thirty responses were analysed; median years of refractive surgery experience was 12.5. The most popular IOL choices for cataract surgery were EDoF lenses (30%), monofocals (20%), and trifocals (20%). The most cited reason for each was better overall visual outcomes (88.9%), fewer unwanted symptoms (66.7%) and best spectacle independence (66.7%), respectively. For RLE, EDoF remained most popular (36.7%), followed by trifocals (30%), and multifocals (16.7%) with the same reasons for choice cited above. Mini-monovision with EDoF lenses was well-regarded (83% recommend for most/select patients), unlike utilising IOL mix-and-match (60% did not recommend). 40% prefer toric IOLs for astigmatism of 1 dioptre (D) or higher, whilst 30% opt for them at < 1D. Conclusions: Experienced UK refractive surgeons prefer newer IOLs with enhanced optics; ≥50% of respondents favoured either EDoF or trifocals for a 'typical' cataract or RLE patient. Notably, respondents have a low corneal astigmatism threshold for toric lenses. Mini-monovision with EDoF IOLs was well-regarded, whilst mix-and-match of different IOL types was less recommended. [ABSTRACT FROM AUTHOR]

Refractive surgery has experienced substantial advancements over the past few years, driven by innovative techniques and continuous technological progress aimed at enhancing visual outcomes and patient satisfaction. Refractive errors such as myopia, hyperopia, and astigmatism affect a significant portion of the global population, impacting quality of life and productivity. Recent advancements have been fueled by a deeper understanding of ocular biomechanics and visual optics, leading to more precise and effective treatments. Traditional methods such as LASIK and PRK have been refined, and new procedures like SMILE (Small Incision Lenticule Extraction) have been introduced, expanding the range of treatable refractive errors and improving safety and predictability. Customized treatments, such as wavefront-guided LASIK and topography-guided PRK, allow for individualized plans tailored to each patient's unique corneal characteristics, enhancing visual acuity and reducing higher-order aberrations. The use of femtosecond lasers in procedures like Femto-LASIK and femtosecond laser-assisted cataract surgery (FLACS) offers unparalleled precision, reducing surgical risks and improving outcomes. Implantable Collamer Lenses (ICLs) and corneal crosslinking (CXL) have emerged as effective options for specific patient groups. Advanced diagnostic tools like optical coherence tomography (OCT) and Scheimpflug imaging have improved surgical planning and complication management. As research and technology continue to evolve, these advancements promise even greater improvements in refractive surgery, addressing the visual needs of the global population. [ABSTRACT FROM AUTHOR]

PURPOSE: The purpose of this study was to compare early visual outcomes, epithelial healing, and stromal haze between transepithelial photorefractive keratectomy (Trans-PRK) using smart pulse technology (SPT) with traditional Trans-PRK. METHODOLOGY: This study is a retrospective, comparative study conducted at a private eye center in "Riyadh, Saudi Arabia," investigating myopic patients who underwent either Trans-PRK with SPT (study group) or traditional Trans-PRK (control group). The patients were assessed preoperatively and followed up at 1 week and 2 months postoperatively. The main outcomes included uncorrected distance visual acuity (UDVA), corneal haze, and corneal epithelial defect. RESULTS: This study included 501 eyes, of them, 222 eyes (44.3%) underwent Trans-PRK with SPT. The UDVA in the study group was significantly better 1 week postoperatively (P < 0.05). For the 2-month follow-up visits, there was no significant difference between the groups. Epithelium healing and stromal haze were comparable in the two groups without significant differences between them. CONCLUSION: Transepithelial photorefractive keratectomy with SPT yielded better short-term visual outcomes than traditional Transepithelial photorefractive keratectomy. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate changes in cataract and refractive surgery practice patterns among members of the Japanese Society of Cataract and Refractive Surgery (JSCRS) over the past 20 years. Study design: Questionnaire survey study. Subjects and methods: Clinical surveys were conducted annually between February and April from 2004 to 2023. Survey questions covered various areas, including cataract surgical techniques, anesthesia, endophthalmitis prophylaxis, toric and presbyopia-correcting intraocular lenses (IOLs), complications, and refractive surgery. Results: The highest (n=554 [36.8%]) and lowest (n=316 [19.1%]) numbers of responses were collected in 2012 and 2016, respectively. In perioperative management, the intraoperative use of polyvinyl alcohol-iodine solution and topical antibiotic prescription 3 days before surgery has increased. The use of intracameral injection at the end of surgery has also significantly increased, although it has not been established as common practice. In anesthesia, there is a clear polarization between the use of topical drops and tenon injection. The use of toric IOLs and presbyopia-correcting IOLs has significantly increased from 2010 to 2023. In the latter, the use of trifocal IOLs has particularly increased. Regarding IOL power calculations, the Barrett True K and the Barrett Universal II formulas are rapidly gaining popularity for application with and without post-laser vision correction, respectively. In refractive surgery, phakic IOLs and corneal refractive therapy have attracted considerable interest, followed by laser in situ keratomileusis. Conclusions: Evaluation of annual clinical survey data over the past two decades provided valuable insights into the shifting practice patterns and clinical opinions among JSCRS members. [ABSTRACT FROM AUTHOR]

Background/Objectives: To evaluate the advanced lens measurement approach (ALMA) formula accuracy using different lens constants available on the user group for laser interference biometry (ULIB) and IOL Con platforms. Methods: In this retrospective, comparative, case-series study, 150 eyes of 160 patients with previous myopic Photorefractive Keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK), who underwent uneventful cataract surgery and IOL implantation, were examined. The ALMA formula was evaluated to calculate the refractive prediction error (PE), analysing four different categories of lens constants: both nominal and optimized A-Constant for SRKT, which are available on the ULIB and IOL Con platforms. An additional analysis was carried out in this study, evaluating if a decreased ULIB optimized constant (DUOC) with different fixed factors (−1.2 −1.3 −1.4 −1.5) could improve refractive outcomes. Median absolute error (MedAE) and percentage of eyes within ±0.50 and ±1.00 diopters (D) of prediction error were measured as the main outcomes. Results: Comparing the lens factors available on ULIB and IOL Con platforms, the ALMA formula reported a lower MedAE and higher percentages of eyes with a refractive PE within 1.0 D using ULIB nominal constants (all p < 0.05). Using DUOC (−1.3), and there was a statistically significant improvement of both MedAE and of the percentages of eyes with PE within ±0.50 D with the ALMA method compared to nominal ULIB constants (all p < 0.05). Conclusions: The impact of different lens factors in the IOL power calculation after myopic LRS should be carefully evaluated. The ALMA formula, in the absence of optimized constants by zeroing the mean error, should be used by subtracting 1.3 from the optimized ULIB constants available on the IOL Con website. This finding suggests further studies to test which of these constants could work better with the other post-refractive surgery formulas. [ABSTRACT FROM AUTHOR]

Refractive surgeries have evolved from the archaic incisional corneal procedures to the use of sophisticated femtosecond lasers and new-generation phakic intraocular lenses (pIOL) for surgical correction of refractive errors. The armamentarium of modern-day refractive surgery includes corneal-based procedures such as photorefractive keratectomy, laser-assisted in situ keratomileusis and keratorefractive lenticule extraction, as well as lensbased pIOL implantation. The current procedures are associated with a high index of efficacy and predictability, with enhanced safety and a significant reduction in sight-threatening complications. Patient counselling and case selection is imperative to achieve optimal visual outcomes and patient satisfaction. This review article provides a comprehensive overview of current refractive surgery procedures, with an emphasis on decision-making. Evolving frontiers in refractive surgeries like customised corneal ablation and presbyopia correcting pIOL are also discussed. [ABSTRACT FROM AUTHOR]

The Zernike representation of wavefronts interlinks low- and high-order aberrations, which may result in imprecise clinical estimates. Recently, the Gatinel–Malet wavefront representation has been introduced to resolve this problem by deriving a new, unlinked basis originating from Zernike polynomials. This new basis preserves the classical low and high aberration subgroups' structure, as well as the orthogonality within each subgroup, but not the orthogonality between low and high aberrations. This feature has led to conversions relying on separate wavefront reconstructions for each subgroup, which may increase the associated numerical errors. This study proposes a robust, minimised-error (lossless) analytical approach for conversion between the Zernike and Gatinel–Malet spaces. This method analytically reformulates the conversion as a nonhomogeneous system of linear equations and computationally solves it using matrix factorisation and decomposition techniques with high-level accuracy. This work fundamentally demonstrates the lossless expression of complex wavefronts in a format that is more clinically interpretable, with potential applications in various areas of ophthalmology, such as refractive surgery. [ABSTRACT FROM AUTHOR]

Purpose: ReLEx (Refractive Lenticule Extraction) Small Incision Lenticule Extraction (SMILE), the second generation of ReLEx Femtosecond Lenticule Extraction (FLEx), is a minimally invasive, flapless procedure designed to treat refractive errors such as myopia, hyperopia, presbyopia, and astigmatism. This review aims to provide a comprehensive overview of the methods for preserving SMILE-derived lenticules and discusses their potential future applications. Methods: A narrative literature review was conducted using PubMed, Scopus, and Web of Science databases, focusing on articles published up to January 2024 and available in English. The authors also evaluated the reference lists of the collected papers to identify any additional relevant research. Results: No standardized protocols currently exist for the storage or clinical application of SMILE-derived lenticules. However, these lenticules present a promising resource for therapeutic uses, particularly in addressing the shortage of donor corneal tissues. Their potential applications include inlay and overlay additive keratoplasty, as well as other ocular surface applications. Further research is needed to establish reliable protocols for their preservation and clinical use. Conclusion: SMILE-derived lenticules offer significant potential as an alternative to donor corneal tissues. Standardizing their storage and application methods could enhance their use in clinical settings. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the three-year visual, refractive outcomes and adverse events of the Eyecryl toric phakic IOL (pIOL) for moderate-to-high myopic astigmatism. Methods: This retrospective study included eligible patients who underwent refractive surgery in one or both eyes with Eyecryl toric pIOL for myopic astigmatism. The efficacy, safety, predictability, rotational stability, vector analysis, and adverse events were evaluated in patients with spherical refraction from − 4.50 to -17.00 diopters (D) and cylindrical refraction from − 0.75 to -5.50 D. Results: Fifty-two eyes of 28 patients were included in the study. The mean efficacy and safety index were 1.12 ± 0.35 and 1.38 ± 0.42, respectively. The mean manifest refraction spherical equivalent was − 10.06 ± 2.69 D and − 0.64 ± 0.61 D preoperatively and postoperatively at 36 months, respectively. The mean manifest astigmatism was − 2.06 ± 1.16 D and − 0.44 ± 0.48 D preoperatively and 36 months postoperative, respectively. During the final examination, 70% of the eyes showed an increase in CDVA of one or more lines compared to their preoperative state. There was a cumulative endothelial cell loss of 3.1% at 36 months postoperatively. One eye developed visually significant anterior subcapsular opacity, whereas another eye experienced pIOL opacification. Conclusion: The Eyecryl toric pIOL demonstrated satisfactory visual acuity and refractive outcomes, as assessed by efficacy, safety and stability over a three-year period. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the culture positivity and distribution of the conjunctival sac bacteria in the perioperative period of corneal refractive surgery. The selected time points of the perioperative period included before the use of antibiotic eye drops, before eye wash (after the use of antibiotic eye drops), after eye wash, and immediately after surgery. Conjunctival specimens obtained at the four time points were cultured to detect the positivity and distribution of bacteria. Before prophylactic antibiotic eye drops were administered, 49 eyes (50%) had positive bacterial culture results, with 45 isolates (91.8%) identified as Staphylococcus epidermidis. The culture positivity rates of the conjunctival sac specimens before eye wash, after eye wash, and immediately after surgery were 19.4%, 3.1%, and 4.1%, respectively. The difference was significant before and after the use of antibiotics and before and after eye wash (both P < 0.001). Staphylococcus epidermidis was the major pathogen in the conjunctival sac before corneal refractive surgery, and the culture positivity rate of the conjunctival bacteria was higher in males. Sixteen of 37 eyes (43.2%) with contact lenses had positive culture results, compared to 33 of 61 eyes (54.1%) without contact lenses (P > 0.05). The judicious preoperative use of antibiotic eye drops combined with the surgical sterile eye wash procedure maximised the removal of conjunctival sac bacteria. Skilled surgical manipulations generally did not increase the risk of infection. [ABSTRACT FROM AUTHOR]

Purpose: To examine complications, visual outcomes, photic patient‐reported symptoms, corneal morphology, IOL tilt, and intraocular pressure after implantation of an intraocular lens (IOL) and iris prosthesis (IP) following iridocyclectomy. Methods: Patients with previous iridocyclectomy treated with an IOL and IP at the Copenhagen University Hospital Rigshospitalet between 2007 and 2018 were included in this national retrospective non‐comparative case series. The assessment encompassed BCVA, PRO questionnaire, corneal topography, and anterior segment OCT. Results: 45 patients were included. Eight of 45 patients were previously treated with ruthenium‐106 brachytherapy in conjunction with iridocyclectomy. Six of 45 patients developed endothelial dysfunction four of whom had received ruthenium‐106 brachytherapy. Five of 45 patients had subluxation of the IOL/IP complex due to incomplete zonula apparatus. BCVA improved for all patients after lens surgery. 26 patients participated in the invited follow‐up examination. 19 of 26 (73%) reported none or mild photic symptoms after IP instalment. Five (19%) reported ongoing severe photic symptoms. The corneal astigmatism significantly increased after iridocyclectomy but did not change after lens surgery. Conclusions: Implantation of an IOL and IP is a safe procedure, alleviating photic symptoms in most patients. It comes with higher risk of complications due to a more demanding procedure and larger surgical traumas from previous treatments. Ruthenium‐106 brachytherapy increases the complication risk. Corneal astigmatism is induced by iridocyclectomy but does not change after lens surgery. [ABSTRACT FROM AUTHOR]

Background/Objectives: This retrospective case series analyzed visual outcomes in patients with a prior history of implantable collamer lens (ICL) implantation who underwent cataract extraction (CE). A secondary aim was to investigate the relationship between vault height and the rate of cataract development. Methods: Visual acuity and refraction measurements were collected after CE at one week, one month and six months. Vault height measurements were correlated to the time until symptomatic cataracts were removed. Results: A total of 44 eyes were analyzed at six months after CE with efficacy and safety indexes of 1.20 ± 1.11 and 1.50 ± 1.06, respectively. In addition, 70% of eyes had a post-operative uncorrected distance visual acuity (UDVA) within one line of pre-operative corrected distance visual acuity (CDVA). Refractive predictability at six months demonstrated that 43% and 69% of eyes were within ±0.25 D and ±0.50 D of SEQ target, respectively. Astigmatism measured by refractive cylinder was ≤0.25 D in 17% and ≤0.50 D in 34% of eyes pre-operatively compared to 40% and 60% of eyes, respectively, at six months post-operatively. Vault heights one week after ICL (p < 0.0081) and one week before CE (p < 0.0154) demonstrated a positive linear regression with the time until CE. Conclusions: This sample population achieved favorable visual outcomes six months after CE, similar to six months after ICL implantation. Patients with a history of ICL implantation will similarly have a good visual prognosis after CE. [ABSTRACT FROM AUTHOR]

Purpose: A cataract is a cloudy area in the crystalline lens. Cataracts are the leading cause of blindness and the second cause of severe vision impairment worldwide. During cataract surgery, the clouded lens is extracted and replaced with an artificial intraocular lens, which restores the optical power. The fabrication of intraocular lenses using existing molding and lathing techniques is a complex and time-consuming process that limits the development of novel materials and designs. To overcome these limitations, we have developed a stereolithography-based process for producing models of clear lens designs without refractive function, serving as a proof of concept. This process has the potential to contribute toward new lens development, allowing for unlimited design iterations and an expanded range of materials for scientists to explore. Methods: Lens-like 3D objects without refractive function were fabricated by using stereolithography. A photopolymerizable resin containing 2-phenoxyethyl acrylate, poly (ethylene glycol) dimethacrylate, and a suitable photoinitiator was developed for the production of lens-like 3D object prototypes. The morphology of the printed devices was characterized by scanning electron microscopy. The transparency and thermal properties were analyzed using spectrophotometry and differential scanning calorimetry, respectively. The biocompatibility of the devices was investigated in a cultured human lens cell line (FHL-124), using a standard lactate dehydrogenase assay, and the lenses were folded and implanted in the human capsular bag model. Results: One-piece lens-like 3D objects without refractive function and with loop-haptic design were successfully fabricated using Stereolithography (SLA) technique. The resulting 3D objects were transparent, as determined by UV spectroscopy. The lactate dehydrogenase test demonstrated the tolerance of lens cells to the prototyping material, and apparent foldability and shape recovery was observed during direct injection into a human capsular bag model in vitro. Conclusions: This proof-of-principle study demonstrated the potential and significance of the rapid prototyping process for research and development of lens-like 3D object prototypes, such as intraocular lenses. [ABSTRACT FROM AUTHOR]

Noninvasive in situ monitoring of viscoelastic characteristics of corneal tissue at elevated temperatures is pivotal for mechanical property-informed refractive surgery techniques, including thermokeratoplasty and photorefractive keratectomy, requiring precise thermal modifications of the corneal structure during these surgical procedures. This study harnesses Brillouin light scattering spectroscopy as a biosensing platform to noninvasively probe the viscoelastic properties of ovine corneas across a temperature range of 25–64 °C. By submerging the tissue samples in silicone oil, consistent hydration and immiscibility are maintained, allowing for their accurate sensing of temperature-dependent mechanical behaviors. We identify significant phase transitions in the corneal tissue, particularly beyond 40 °C, likely due to collagen unfolding, marking the beginning of thermal destabilization. A subsequent transition, observed beyond 60 °C, correlates with collagen denaturation. These phase transformations highlight the cornea's sensitivity to both physiologically reversible and irreversible viscoelastic changes induced by mild to high temperatures. Our findings underscore the potential of the Brillouin biosensing technique for real-time diagnostics of corneal biomechanics during refractive surgeries to attain optimized therapeutic outcomes. [ABSTRACT FROM AUTHOR]

Background: To compare the repeatability and reproducibility of corneal and corneal epithelial thickness mapping using anterior segment optical coherence tomography (AS-OCT) according to tear film break-up time (TBUT). Methods: The included eyes were divided into three subgroups according to TBUT (group 1: TBUT ≤ 5 s, group 2: 5 s < TBUT ≤ 10 s, and group 3: TBUT > 10 s). All eyes were imaged separately thrice by two operators to obtain the thickness maps (TMs) of the cornea and corneal epithelium based on spatial zones encompassing a 9-mm-diameter area. Each TM consisted of 25 areas. Intraoperator (repeatability) and interoperator (reproducibility) standard deviations (Sws), coefficients of variation (CoVs), and intraclass correlation coefficients (ICCs) among the tests were calculated and compared in all the areas. Results: Altogether, 132 eyes of 67 subjects were included (50, 47, and 35 eyes in groups 1, 2, and 3; respectively). The ICCs of corneal epithelial thickness and corneal thickness were > 0.75 in most of the areas. Pairwise comparisons showed that AS-OCT exhibited lower repeatability in group 1 than in groups 2 and 3 (P < 0.05). However groups 2 and 3 showed similar results. Sws and CoVs of corneal epithelial thickness exhibited no significant interoperator differences. While no significant differences were observed in corneal thickness in most of the areas. Conclusions: TBUT significantly influences the repeatability of corneal and corneal epithelial thickness measurements. Poor tear film stability requires careful evaluation of corneal epithelial thickness. [ABSTRACT FROM AUTHOR]

Purpose: Noncontact instruments like Pentacam Scheimpflug imaging allows assessment of corneal Pachymetry with good repeatability and reproducibility as compared to ultrasound. We aimed to differentiate corneal thinnest point and central corneal thickness on basis of magnitude and location, and its relation to age, sex, laterality, spherical equivalent and astigmatism in myopes. Study Design: Correlational study. Place and Duration of Study: Hashmani’s Hospital Karachi from March 2021 to May 2021. Methods: We enrolled 92 eyes (38 males, 54 females) of myopic adult patients from age 19-52 years. Prescreening of myopes (-0.75DS to -8.00DS) included refraction, slit-lamp biomicroscopy and fundoscopy. Participants with ocular disease, previous ocular surgery, contact lens and history of any eye drops use were excluded from the study. Pentacam was used to determine CCT, thinnest corneal thickness (TCT) and vector location of TCT. Results: Majority (77%) of the eyes had myopic astigmatism whereas 23% had simple myopia. We found statistically significant difference between CCT and TCT. Inferotemporal and inferonasal displacements of TCT were noted. No difference was noted between TCT and its location among the two sexes. We observed that alteration among the CCT and TCT in both age groups was statistically significant. Conclusion: CCT and TCT are separate measurements and both are important since their magnitudes and locations might differ greatly especially with age. Both reading have significance in determining post-operative risk of corneal ectasia, assessment for refractive surgeries and early detection of ectatic conditions like keratoconus. [ABSTRACT FROM AUTHOR]

Purpose: To compare early changes in the corneal biomechanical parameters after photorefractive keratectomy (PRK) and small incision lenticule extraction (SMILE) and their correlations with corneal shape parameters. Methods: One hundred twenty four eyes received myopic PRK and SMILE for similar amounts of myopia. Corneal tomography with Pentacam HR, biomechanical parameters using Corvis ST, and Ocular Response Analyzer (ORA) were evaluated before and 2 weeks after surgery. The change in each parameter was compared between groups, while the difference in central corneal thickness and cornea-compensated intraocular pressure measured before and after surgery were considered as covariates. Results: A significant reduction was seen in the corneal stiffness parameter at first applanation, and an increase in deformation amplitude ratio (DAR), and integrated inverse radius (IIR) in both groups after surgery (p < 0.001) Changes in DAR, and IIR were significantly greater in the SMILE than in the PRK group (p < 0.001) Corneal hysteresis (CH) and corneal resistance factor (CRF) decreased in both SMILE and PRK groups after surgery, (p < 0.001) with no statistically significant difference between groups (p > 0.05) Among new Corvis ST parameters, DAR showed a significant correlation with changes in Ambrosio relational thickness in both groups (p < 0.05). Conclusions: Both techniques caused significant changes in corneal biomechanics in the early postoperative period, with greater elastic changes in the SMILE group compared to the PRK group, likely due to lower tension in the SMILE cap and thinner residual stromal bed in SMILE. There were no differences in viscoelastic changes between them, so the lower CH may reflect the volume of tissue removed. [ABSTRACT FROM AUTHOR]

Keratoconus (KC) is a progressive corneal condition characterized by ectasia, which causes progressive myopia and irregular astigmatism, resulting in decreased vision. Visual rehabilitation and refractive error management of keratoconic eyes are challenging. There is increasing interest in using the implantable collamer lens (ICL) off label in KC in light of encouraging reports of safety and efficacy in stable disease. The main concerns in considering ICL for visual rehabilitation include stability of the disease, magnitude of the refractive error, type of astigmatism, keratometric readings, and patient satisfaction with spectacles. This article reviews the indications for ICL in keratoconus and the timing between ICL implantation and corneal crosslinking and/or intrastromal corneal ring segment procedures. Additionally, we review challenges with ICL sizing in keratoconus, along with the factors and frequency associated with exchange and rotation post-ICL implantation.

Purpose: To investigate the changes in posterior corneal elevation after small incision lenticule extraction (SMILE) surgery in eyes of different myopia severity. Methods: A total of 141 eyes of 86 patients were recruited and followed at 1 month, 3 months, 6 months, and 12 months after SMILE surgery. The eyes were divided into four groups according to the spherical equivalent (SE): low myopia (LM, −3.00 D≤SE 0.05). There were significant reductions of post-operative PCAE compared to baseline in the LM group (P = 0.038) and HM group (P 0.05). TPC was significantly decreased after the surgery in the MM group (P = 0.022) and the HM group (P 0.05). TPC was significantly different among the three groups at 3 months, 6 months and 12 months (all P < 0.05), but not at baseline (P = 0.066) or 1 month (P = 0.080). Conclusion: In the first year after SMILE surgery, PCAE was decreased in both LM and HM eyes, and TPC were decreased in MM and HM eyes, but PME was stable after the surgery.