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Background: To investigate the correlation between the corneal biomechanical parameter stress-strain index (SSI) and axial length (AL) in moderately elongated eye (MEE) and severely elongated eye (SEE).Methods: This study included 117 eyes from 117 participants. Among them, 59 (50.4%) had MEE (AL 0.05). CCT was negatively correlated with AL (r = −0.289, p < 0.05) and ACV positively correlated with AL (r = 0.444, p < 0.001) in the MEE group. Neither CCT nor ACV was correlated with AL (p > 0.05) in the SEE group.Conclusion: Corneal biomechanical parameter SSI, which represents the stiffness of corneal tissue, was lower in the SEE group than in the MEE group. When analyzed separately, SSI was negatively correlated with AL in the MEE group, but not in the SEE group, which may provide insight into different ocular growth patterns between lower myopia and higher myopia.

Optical coherence tomography angiography (OCTA) is the most relevant evolution based on optical coherence tomography (OCT). OCTA can present ocular vasculature, show detailed morphology for assessment, and quantify vessel parameters without intravenous dye agent. Research on the anterior segment OCTA (AS-OCTA) is only in its initial phase, and its advances in clinical diagnosis and treatment efficacy evaluations require a detailed comparison to traditional imaging methods. In this review of AS-OCTA, we summarize its technical features, imaging advances, current clinical applications in various eye diseases, as well as its limitations and potential future directions. AS-OCTA offers potential advantages in ophthalmic imaging, and with further development it could become a common tool in the near future.

Background: The purpose of this study was to analyze the ocular biometric parameters of primary angle-closure disease (PACD) in younger patients and compare them with those of elderly patients.Methods: This clinic-based, cross-sectional study included 154 eyes of 154 patients with PACD, consisting of 77 eyes of patients aged 40 years or younger and 77 eyes of patients older than 40. The PACD case definition was compatible with the ISGEO definition. Anterior segment parameters were measured by ultrasound biomicroscopy, axial length (AL) and lens thickness (LT) were measured by A-scan ultrasonography measurements, and the thickness of the retina and choroid were measured by optical coherence tomography. The differences in ocular biometric parameters between different age groups were compared by independent sample t-tests or Mann-Whitney U tests, and the correlation between the parameters and age was analyzed.Results: Compared to older PACD patients, the lens vault(LV),LV/LT and subfoveal choroidal thickness (SFCT) of younger patients were larger, while the peripheral and mean iris thickness (IT), trabecular-ciliary angle (TCA), ciliary body thickness (CBT), AL and LT were smaller (all P < 0.01). There was no significant difference in anterior chamber depth, anterior chamber width, pupil diameter, angle opening distance at 500 μm from the scleral spur, anterior chamber angle and iris convexity between the two groups (all P > 0.05). AL, LT, IT, TCA and CBT were positively associated with age (all P < 0.001), while LV and SFCT were negatively associated with age (P = 0.027 and P < 0.001, respectively).Conclusions: Compared with elderly patients, younger PACD patients had more anteriorly positioned lenses, thinner and more anteriorly rotated ciliary bodies, thicker choroids, and shorter axial length. These characteristics might be important anatomical bases for the earlier onset of PACD and the higher risk of malignant glaucoma after filtering surgery.

How to enhance the bioavailability and prolong the residence time of drugs in the eye present the major barriers to traditional eye delivery. Nanotechnology has been widely used in ocular drug delivery systems because of its advantages of minimizing adverse reactions, decreasing the frequency of administration, prolonging the release time, and improving the bioavailability of the drug in the eye. As natural product-based nanostructured systems, bioinspired nanostructured systems have presented as less toxic, easy to prepare, and cost-effective and have potential application value in the field of nanotechnology. A systematic classification of bioinspired nanostructured systems based on their inspiration source and formulation and their brief applications in disease are presented here. A review of recent research progress of the bioinspired nanostructured systems for the treatment of the anterior and posterior segment of ocular disorders is then presented in detail. Finally, current challenges and future directions with regard to manufacturing bioinspired nanomaterials are provided.

Anterior segment optical coherence tomography (AS-OCT), being non-invasive and well-tolerated, is the method of choice for an in vivo investigation of ciliary muscle morphology and function. The analysis requires the segmentation of the ciliary muscle, which is, when performed manually, both time-consuming and prone to examiner bias. Here, we present a convolutional neural network trained for the automatic segmentation of the ciliary muscle in AS-OCT images. Ciloctunet is based on the Freiburg U-net and was trained and validated using 1244 manually segmented OCT images from two previous studies. An accuracy of 97.5% for the validation dataset was achieved. Ciloctunet’s performance was evaluated by replicating the findings of a third study with 180 images as the test data. The replication demonstrated that Ciloctunet performed on par with two experienced examiners. The intersection-over-union index (0.84) of the ciliary muscle thickness profiles between Ciloctunet and an experienced examiner was the same as between the two examiners. The mean absolute error between the ciliary muscle thickness profiles of Ciloctunet and the two examiners (35.16 µm and 45.86 µm) was comparable to the one between the examiners (34.99 µm). A statistically significant effect of the segmentation type on the derived biometric parameters was found for the ciliary muscle area but not for the selective thickness reading (“perpendicular axis”). Both the inter-rater and the intra-rater reliability of Ciloctunet were good to excellent. Ciloctunet avoids time-consuming manual segmentation, thus enabling the analysis of large numbers of images of ample study cohorts while avoiding possible examiner biases. Ciloctunet is available as open-source.

Purpose: To analyze changes in the anterior segment, retinal vessel density, and choroidal thickness (ChT) after orthokeratology (Ortho-K).Methods: Myopic children were enrolled from Ruijin Hospital, Shanghai, China. Ortho-K lenses and single-vision spectacles were fitted for myopia correction. Ocular measurements were taken at baseline and 6 months, including axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), white to white (WTW), ChT, macular vessel density (MVD), and optic disc vessel density (OVD).Results: Seventy-six patients were enrolled in this study, including 40 in the Ortho-K group and 36 in the control group. At baseline, no parameters between the two groups were statistically different. After 6 months, changes in CCT and ACD decreased in the Ortho-K group compared with those in the control group (p < 0.05); LT and ChT in the Ortho-K group were thicker than those in the control group (p < 0.05), while there was no difference in MVD and OVD compared with those in the control group (p > 0.05). There were moderate positive correlations between ChT and LT and between ChT and OVD in the Ortho-K group (p < 0.05).Conclusion: The changes in the anterior and posterior segments of the eye after Ortho-K lens wearing suggest that the human eye has a powerful compensatory effect on the imposed defocus.

Background: Human immunodeficiency virus and acquired immunodeficiency syndrome (HIV/AIDS) causes impairment to the immune system, which then leads to immunocompromised conditions, and allows for opportunistic infection to invade many organs of the human body. Ocular involvement is very common; the various ocular complications may be asymptomatic and they may be the initial manifestations of the underlying diseases. Aim: This study aimed to determine the prevalence and the type of ocular manifestations that occur in HIV and AIDS patients. Setting: The study was conducted on ART (antiretroviral treatment) clinic patients in the Department of Ophthalmology at the Steve Biko Academic Hospital, Pretoria. Methods: This descriptive, cross-sectional study was conducted on HIV and AIDS patients referred from the ART clinic for complete ophthalmological evaluation, irrespective of the immune system status and presence or absence of symptoms. All the participants underwent an ophthalmologic evaluation, which included case history and ocular examinations of both anterior and posterior segments. Results: Out of the 177 participants, 72.3% had visual acuity of between 6/3 to 6/18, 10% had poor vision, 7% had lost one eye to ocular complications and 5% were blind. The most common anterior segment manifestations were uveitis and dry eye, whilst HIV-related retinopathy and papilledema were the most prevalent conditions in the posterior segment. Only three participants had third cranial nerve palsy. Conclusion: The prevalence of ocular manifestations was significantly higher with lower CD4+ cell counts, which could be regarded as predictors for the occurrence of ocular morbidity in HIV and AIDS patients.

Introduction: To describe anterior segment optical coherence tomography angiography (AS-OCTA) imaging to monitor corneal vascularisation (CoNV) and scar reduction after combined fine-needle diathermy (FND) with subconjunctival ranibizumab.Methods: Prospective clinical study of six eyes from six subjects with corneal scar and CoNV which underwent combined FND with subconjunctival ranibizumab. All eyes were imaged using slit-lamp photography (SLP) and AS-OCTA (Optovue, Inc., Fremont, CA, wavelength: 840 nm) before and after the operation, with two independent masked assessors analysing all images. Main outcome measures were changes in median corneal scar area and vessel density (AS-OCTA) comparing pre- and postoperative imaging up to month 3 and 6.Results: The mean age of the subjects was 60 ± 23 years, with three males and three females. CoNV and corneal scarring involving the visual axis were present in all eyes, secondary to previous infective keratitis (n = 3), severe blepharokeratoconjunctivitis (n = 2), or chemical injury (n = 1). Follow-up time frame ranged from 2 to 6 months postoperation. There was a reduction in median corneal scar area from 30.2 mm2 (IQR 18.7-38.5) before surgery to 14.8 mm2 (IQR 7.1-19.6) after surgery, with a median reduction of 37.1% (IQR = - 3.1-86.9, p = 0.046). There was also a reduction in median cornea vessel density (AS-OCTA) from 20.8% (IQR 16.1-20.8) before surgery to 17.6% (IQR 14.0-17.6) after surgery, with a median reduction of 15.1% (IQR 13.2-15.1, p < 0.001).Conclusions: Combined imaging of SLP and AS-OCTA is useful for monitoring treatment response of corneal scarring and CoNV after combined FND with subconjunctival Ranibizumab. [ABSTRACT FROM AUTHOR]

Corneal neovascularization (CoNV) is a vision-threatening ocular disease commonly secondary to infectious, inflammatory, and traumatic etiologies. Slit lamp photography, in vivo confocal microscopy, angiography, and optical coherence tomography angiography (OCTA) are the primary diagnostic tools utilized in clinical practice to evaluate the vasculature of the ocular surface. However, there is currently a dearth of comprehensive literature that reviews the advancements in imaging technology for CoNV administration. Initially designed for retinal vascular imaging, OCTA has now been expanded to the anterior segment and has shown promising potential for imaging the conjunctiva, cornea, and iris. This expansion allows for the quantitative monitoring of the structural and functional changes associated with CoNV. In this review, we emphasize the impact of algorithm optimization in anterior segment-optical coherence tomography angiography (AS-OCTA) on the diagnostic efficacy of CoNV. Through the analysis of existing literature, animal model assessments are further reported to investigate its pathological mechanism and exhibit remarkable therapeutic interventions. In conclusion, AS-OCTA holds broad prospects and extensive potential for clinical diagnostics and research applications in CoNV. [Display omitted] • Faults refer to rough and invasive are evident in photography and angiography. • OCTA realizes the qualitative and accurate diagnosis of corneal neovascularization. • Evolution of algorithms allow OCTA in further clinical and experimental practice. • It demands solution to address artifacts and narrow view to optimize the technology. [ABSTRACT FROM AUTHOR]

PurposeThe guinea pig is being used increasingly as a model of human myopia. As accommodation may influence the effects of manipulations used in experimental myopia models, understanding the accommodative ability of guinea pigs is important. Here, nonselective muscarinic agonists were used as pharmacological tools to study guinea pig accommodation.MethodsMeasurements were made on 15 pigmented guinea pigs. For in vivo testing, animals were anesthetized and, following baseline measurements, 2% pilocarpine was applied topically. Measurements included A-scan ultrasonography, optical coherence tomography (OCT) imaging, corneal topography, and refraction. In vitro lens scanning experiments were performed using anterior segment preparations, with measurements before and during exposure to carbachol. Anterior segment structures were examined histologically and immunohistochemistry was done to characterize the muscarinic receptor subtypes present.ResultsIn vivo, pilocarpine induced a myopic shift in refractive error coupled to a small, but consistent decrease in anterior chamber depth (ACD), a smaller and more variable increase in lens thickness, and a decrease in pupil size. Lens thickness increases were short-lived (10 minutes), while ACD and pupil size decreased over 20 minutes. Corneal curvature was not significantly affected. Carbachol tested on anterior segment preparations in vitro was without effect on lens back vertex distance, but did stimulate pupil constriction. Immunohistochemistry indicated the presence of muscarinic receptor subtypes 1 to 5 in the iris and ciliary body.ConclusionsThe observed pilocarpine-induced changes in ACD, lens thickness, and refraction are consistent with active accommodation in the guinea pig, through cholinergic muscarinic stimulation.

: Clinician-scientists bridge the gap between basic research and patient care. At the 2012 Annual Meeting, a symposium highlighting the application of cutting-edge optometric research within the anterior segment was held to present and discuss some of the recent basic scientific advances that will both shape and guide the development of future clinical care practices. This article summarizes this work, bringing together four experts, all clinician-scientists in the field of cornea and ocular surface. Collectively, this work provides new insights to clinicians and researchers alike, as well as brings forth a greater appreciation of the impact of ongoing optometric bench research in advancing clinical care.

PURPOSE: To investigate the effects of SSRIs on cornea and lens density, intraocular pressure (IOP) and anterior chamber parameters, including anterior chamber volume (ACV), anterior chamber depth (ACD), corneal volume (CV) and central corneal thickness (CCT), in patients with depression during a three-month follow-up period. METHOD: In this prospective study, 31 total patients, who were prescribed SSRIs for depression, were recruited. Sertraline, 50 mg/daily, was given to ten patients; 11 received Escitalopram, 10 mg/daily; and ten were treated with Fluoxetine, 20 mg/daily. The parameters recorded were corneal density (CD), lens density (LD), IOP, ACV, ACD, CV and CCT at the start of treatment, as well as at one-week, one-month, and three-month follow-ups. RESULTS: The study revealed that there was no risk of cataract development from three months of SSRI intake. Significant decrease in ACD was recorded at the one-week follow up; however, after three months, this decrease was insignificant compared to the baseline. ACV, CV, CCT, CD and LD showed no significant alterations in any of the follow up examinations over the three-month period. IOP, however, significantly fell (a P value of 0.004). CONCLUSION: In this study, SSRI use does not seem to be associated with an increased risk of cataract or glaucoma or with changes in CD and LD. Long-term follow-up is necessary to determine the actual risk of cataract or glaucoma with SSRI intake.

Pars plana vitrectomy is currently the most common technique used in retinal surgery. Although primarily involving the posterior segment of the eye it also affects the anterior segment. As this is a less published topic, the aim of this paper was to review the literature on changes in the anterior segment after uncomplicated pars plana vitrectomy using data based literature search. The conclusions are that even in otherwise ophthalmologically healthy patients, complications may occur in the anterior segment. Surgeons need to pay utmost attention in glaucoma patients and in those with endothelial insufficiency who are at highest risk of complications. He/she must also correctly plan a potential cataract surgery if not already done earlier. From the literature, most of the changes in the anterior segment after uncomplicated PPV are found to be temporary.

Tetsuya Muto,1 Tomoharu Nishimura,1 Masaaki Sakamoto,1 Takenori Inomata,2 Shigeki Machida11Department of Ophthalmology, Dokkyo Medical University Saitama Medical Center, Koshigaya, Japan; 2Department of Ophthalmology, Juntendo University Faculty of Medicine, Tokyo, JapanPurpose: To identify from the anterior segment the structural variables of the eyes that can be used to distinguish acute primary angle-closure (APAC) eyes or primary angle-closure suspect (PACS) eyes from normal eyes.Patients and methods: We used a Pentacam scanner to measure participants’ anterior eye segments. We assessed each anterior segment structure variable on the basis of receiver operating characteristic curves using the area under the curve (AUC).Results: AUCs for eyes in men with APAC were 1.000 for central anterior chamber depth (ACD), 0.982 for peripheral ACD, 0.916 for anterior chamber angle (ACA), and 0.992 for anterior chamber volume (ACV). AUCs for eyes in women with APAC were 0.997 for central ACD, 0.942 for peripheral ACD, 0.922 for ACA, and 0.946 for ACV. AUCs for eyes in men with PACS were 0.933 for central ACD, 0.930 for peripheral ACD, 0.887 for ACA, and 0.937 for ACV. AUCs for eyes in women with PACS were 0.960 for central ACD, 0.957 for peripheral ACD, 0.937 for ACA, and 0.937 for ACV. The negative predictive values (%) in men with APAC were 100 for all the four variables (central ACD, peripheral ACD, ACA, and ACV). The negative predictive values (%) in women with APAC were 100 for central ACD, 98.7 for peripheral ACD, 97.1 for ACA, and 97.9 for ACV. The negative predictive values (%) in men with PACS were 98.6 for central ACD, 100 for peripheral ACD, 98.5 for ACA, and 99.4 for ACV. The negative predictive values (%) in women with PACS were 100 for central ACD, 98.7 for peripheral ACD, 97.1 for ACA, and 97.9 for ACV.Conclusions: The central ACD, peripheral ACD, ACA, and ACV measurements seem to be excellent markers to identify eyes without APAC or PACS.Keywords: acute primary angle-closure, anterior segment, Pentacam, glaucoma

Abstract Introduction To evaluate the effects of cycloplegia on the biometric components and anterior segment parameters of the eye. Methods In this cross-sectional study, changes to axial length (AL), anterior chamber depth (ACD) lens thickness, anterior chamber angle (ACA) and volume, corneal thickness in the pupil center (PC), corneal curvature (CC) and white-to-white (WTW) following cycloplegia induced by tropicamide 1% in 42 eyes of patients aged 23–58 years were assessed. Biometric components and anterior segment parameters were measured using an IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany) and a Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany), respectively. Results Significant statistical changes in ACD (increased by 0.06 ± 0.05 mm; p 0.05). Also, a significant inferior displacement of the PC along the vertical axes was seen (p = 0.020). Conclusion Cycloplegia resulted in a deeper ACD and thinner lens thickness. These changes should be considered in determining intraocular lens (IOL) power to prevent refractive surprises in cataract surgery and also in the phakic IOL implantation.

AIM: To compare the ability of spectral-domain optical coherence tomography(SD-OCT)and slit lamp biomicroscopy to detect anterior segment findings in patients with closed globe injury.METHODS: This is an observational, cross-sectional study. Sixteen patients with a closed globe injury were consecutively recruited from January 2010 to July 2015 in Huizhou Municipal Central Hospital. All patients underwent complete ophthalmic examination, including assessment of visual acuity, measurement of intraocular pressure using a noncontact tonometry, and slit lamp biomicroscopy. SD-OCT was used to examine the anterior segments of all injured eyes. Two patients had bilateral ocular injuries and received bilateral SD-OCT examinations. The OCT findings of the cornea, iris, anterior chamber and lens were recorded and compared with findings seen using slit lamp biomicroscopy.RESULTS: All 18 eyes were examined by SD-OCT had hyphema occupying at least one-third of the anterior chamber volume. Sixteen eyes had corneal edema and corneal abrasion detected on both slit lamp biomicroscopy and OCT examination. OCT examination was also able to detect Descemet's membrane detachment(n=7), angle recession(n=6), lens subluxation(n=3)and iridodialysis(n=3).CONCLUSION: SD-OCT was able to identify features of closed globe injury that were otherwise not visible on slit lamp biomicroscopy. SD-OCT may have advantages over clinical examination in cases of closed globe injury.

Abstract Background The goal was to quantitatively analyze the bulbar conjunctival microvascular density using optical coherence tomography angiography (OCTA) and compare it to the vessel density using functional slit-lamp biomicroscopy (FSLB). Methods Temporal bulbar conjunctiva of 20 eyes (10 healthy subjects) was imaged using both OCTA and FSLB. Image processing was performed including equalization, de-noising, thresholding, and skeletonization. The vessel density was measured by fractal analysis (box counting, Dbox) and pixel counting (%). Results Vessel density (Dbox) of the bulbar conjunctiva obtained using OCTA was 1.28 ± 0.01 Dbox, which was significantly lower than the result (1.32 ± 0.01 Dbox, P 0.05) between both instruments were found in both vessel density methods (Dbox and percentage). However, in each of the devices, vessel density in Dbox was significantly correlated with the vessel density in percentage (r = 1.0 for FSLB and r = 0.98 for OCTA, both P

Abstract Optical coherence tomography angiography (OCTA) is a rapid and non-invasive technique for imaging vasculature in the eye. As OCTA can produce high-resolution cross-sectional images and allow depth-resolved analysis for accurate localization of pathology of interest, it has become a promising method for anterior segment imaging. Furthermore, OCTA offers a more patient-friendly alternative to the conventional invasive dye-based fluorescent angiography. However, conventional OCTA systems are typically designed and optimized for the posterior segment of the eye, and thus using OCTA for anterior segment imaging can present several difficulties and limitations. In this review, we summarized the recent developments and clinical applications in anterior segment OCTA (AS-OCTA) imaging, such as for the cornea, iris, sclera and conjunctiva. We also compared commercially available OCTA systems, discussed the limitations of adapting current OCTA technology for the anterior segment imaging, and proposed possible future directions for AS-OCTA systems. AS-OCTA provides potential for future clinical applications such as diagnosis of corneal and iris pathologies, pre-operative surgical planning, assessment of new anti-angiogenic therapeutics or evaluation of limbal stem cell deficiency. With further development, OCTA for anterior segment imaging in the clinics may become common in the near future.

Most cases of Stickler syndrome are due to autosomal-dominant COL2A1 gene mutations leading to abnormal type II collagen. Ocular findings include axial eye lengthening with vitreal degeneration and early-onset glaucoma, which can result in vision loss. Although COL2A1 is a major player in cartilage and bone formation, its specific role in eye development remains elusive. We investigated the role of Col2a1a in neural crest migration and differentiation during early zebrafish eye development. In situ hybridization, immunofluorescence, live imaging, exogenous treatments [10 μM diethylaminobenzaldehyde (DEAB), 100 nM all-trans retinoic acid (RA) and 1–3% ethanol (ETOH)] and morpholino oligonucleotide (MO) injections were used to analyze wildtype Casper (roy−/−;nacre−/−), TgBAC(col2a1a::EGFP), Tg(sox10::EGFP) and Tg(foxd3::EGFP) embryos. Col2a1a colocalized with Foxd3- and Sox10-positive cells in the anterior segment and neural crest-derived jaw. Col2a1a expression was regulated by RA and inhibited by 3% ETOH. Furthermore, MO knockdown of Col2a1a delayed jaw formation and disrupted the ocular anterior segment neural crest migration of Sox10-positive cells. Interestingly, human COL2A1 protein rescued the MO effects. Altogether, these results suggest that Col2a1a is a downstream target of RA in the cranial neural crest and is required for both craniofacial and eye development.

Tele-ophthalmology is a rapidly evolving and exciting field that has become increasingly relevant amidst the current global pandemic. With advancements in technology, many components of an evaluation previously possible only in an office setting are becoming possible remotely, paving the way for at-home visits. Examples of these technologies include measurement of visual acuity using smartphones, remote monitoring of intraocular pressure using self-administered tonometers or implantable sensors, and use of digitally acquired slit-lamp or smartphone images for diagnosis of anterior segment pathology. While many examples showcasing the utility of telemedicine have been shown for diseases such as diabetic retinopathy, concerted efforts are needed to develop similar technology for anterior segment diseases. As technology continues to advance, it may be possible to diagnose and manage more anterior segment disease with telemedicine. [ABSTRACT FROM AUTHOR]

Obtaining a clear assessment of the anterior segment is critical for disease diagnosis and management in ophthalmic telemedicine. The anterior segment can be imaged with slit lamp cameras, robotic remote controlled slit lamps, cell phones, cell phone adapters, digital cameras, and webcams, all of which can enable remote care. The ability of these devices to identify various ophthalmic diseases has been studied, including cataracts, as well as abnormalities of the ocular adnexa, cornea, and anterior chamber. This article reviews the current state of anterior segment imaging for the purpose of ophthalmic telemedical care. [ABSTRACT FROM AUTHOR]

Background - Implantable Collamer Lens are an alternative to conventional refractive procedures. Its implant may develop complications that can be lowered if reliable measurements are made before and after surgery. The aim of this study is to analyze the inter-operator variability of before and after surgery measurements, using images obtained through anterior segment optical coherence tomography. Methods - Using the SD-OCT Spectralis® equipment, two orthoptists measured the inter scleral spur diameter, pupillary diameter, and vault, in 60 images of 30 eyes implanted with ICL lenses. For the statistical analysis, the mean value t-test for independent samples was used, and the intraclass correlation coefficient was also calculated. Bland-Altman Plots were also created. Results - Assessing the intraclass correlation coefficient, all the studied measurements showed an excellent agreement between the two operators. For the t-test, statistically significant differences were observed between the two operators only for vault measurements, with possible clinical impact. As for the measures of inter scleral spur diameter, despite the absence of statistically significant differences, there were some differences with clinical significance that should be corrected in the future. Conclusions - Inter-operator measurement differences should be evaluated statistically but also clinically because, despite the absence of statistically significant differences, their clinical impact should be assessed, weighted, and corrected when needed. [ABSTRACT FROM AUTHOR]

Objectives: This study was designed to investigate the long-term effects of intravitreal anti-vascular endothelial growth factor (VEGF) injections on ocular surface and anterior segment parameters. A comparison was performed of the treated eye and the fellow healthy eye. Methods: The study group included patients who had received at least 3 intravitreal injections of anti-VEGF agents (bevacizumab, ranibizumab, or aflibercept) for retinal vascular disorders. All of the subjects were treated in only 1 eye. A complete ophthalmological examination, including evaluation of tear break-up time (TBUT), the Schirmer 1 test, the Oxford Grading Scale, and the Ocular Surface Disease Index (OSDI) questionnaire, corneal topography, and specular microscopy were performed in both eyes 1 month after the last injection. Results: In this study, 49 eyes of 49 patients who underwent regular intravitreal injection in 1 eye were enrolled. The mean age was 63.85±9.8 years (range: 29-86 years). A mean of 4.06±1.7 (range: 3-11) injections were administered. There was no significant difference in the intraocular pressure, TBUT, Schirmer 1, fluorescein staining, or specular microscopy parameters (p>0.05). The mean non-invasive TBUT first and average values; the central, thinnest, and apex corneal thickness measurements; the anterior chamber depth, irido-corneal angle, corneal volume, and keratometry values were similar in each individual (p>0.05 for all parameters). The mean OSDI score was 27.5±17.6 for the injected eyes and 15.9±12.9 for the non-injected eyes (p<0.0001). Conclusion: Intravitreal anti-VEGF injections had no effect on ocular surface, corneal endothe-lium, and anterior segment parameters. [ABSTRACT FROM AUTHOR]

Eye drops are the most common and convenient route of topical administration and the first choice of treatment for many ocular diseases. However, the ocular bioavailability of traditional eye drops (i.e., solutions, suspensions, and ointments) is very low because of ophthalmic physiology and barriers, which greatly limits their therapeutic effect. Over the past few decades, many novel eye drop delivery systems, such as prodrugs, cyclodextrins, in situ gels, and nanoparticles, have been developed to improve ophthalmic bioavailability. These novel eye drop delivery systems have good biocompatibility, adhesion, and propermeation properties and have shown superior performance and efficacy over traditional eye drops. Therefore, the purpose of this review was to systematically present the research progress on novel eye drop delivery systems and provide a reference for the development of dosage form, clinical application, and commercial transformation of eye drops.

A high-speed (100 kHz A-scans/s) complex conjugate resolved 1 μm swept source optical coherence tomography (SS-OCT) system using coherence revival of the light source is suitable for dense three-dimensional (3-D) imaging of the anterior segment. The short acquisition time helps to minimize the influence of motion artifacts. The extended depth range of the SS-OCT system allows topographic analysis of clinically relevant images of the entire depth of the anterior segment of the eye. Patients with the type 1 Boston Keratoprosthesis (KPro) require evaluation of the full anterior segment depth. Current commercially available OCT systems are not suitable for this application due to limited acquisition speed, resolution, and axial imaging range. Moreover, most commonly used research grade and some clinical OCT systems implement a commercially available SS (Axsun) that offers only 3.7 mm imaging range (in air) in its standard configuration. We describe implementation of a common swept laser with built-in k-clock to allow phase stable imaging in both low range and high range, 3.7 and 11.5 mm in air, respectively, without the need to build an external MZI k-clock. As a result, 3-D morphology of the KPro position with respect to the surrounding tissue could be investigated in vivo both at high resolution and with large depth range to achieve noninvasive and precise evaluation of success of the surgical procedure.

Purpose: To evaluate the agreement of different biometric parameters obtained using intraoperative spectral-domain optical coherence tomography (SD-OCT) and two swept-source optical coherence tomography (SS-OCT) based biometers. Methods: 102 eyes were assessed using the intraoperative SD-OCT integrated into the Catalys femtosecond-laser, and the IOLMaster 700 and Anterion SS-OCT-based-biometers. Central corneal thickness (CCT), anterior chamber depth (ACD), white-to-white (WTW), and lens thickness (LT) were measured. Results: There were statistically significant differences for CCT, ACD, WTW and LT between devices (p < 0.001). The mean difference for ACD ranged from −0.067 to −0.250 mm, with the largest mean difference being between the IOLMaster 700 and Catalys. CCT mean differences ranged from 7 to 32 µm, with the largest mean difference being between the Anterion and Catalys. For WTW, the comparison between the IOLMaster 700 vs Catalys showed the largest mean difference (0.38 mm). However, the mean differences for LT from all three devices were quite similar, ranging from −0.02 to −0.08 mm. Conclusions: SS-OCT biometers showed good agreement for ACD, CCT, WTW and LT. The SD-OCT showed ACD, CCT and WTW values that do not seem to be interchangeable with the SS-OCT biometers; however, this device did show excellent agreement in the case of LT. [ABSTRACT FROM AUTHOR]

In his beautiful book, Consilience: The Unity of Knowledge , the eminent biologist Edward O Wilson, advocates the need for integration and reconciliation across the sciences. He defines consilience as "literally a 'jumping together' of knowledge with a linking of facts ... to create a common groundwork of explanation". It is the premise of this paper that as much as basic biomedical research is in need of data generation using the latest available techniques- unifying available knowledge is just as critical. This involves the necessity to resolve contradictory findings, reduce silos, and acknowledge complexity. We take the cornea and the lens as case studies of our premise. Specifically, in this perspective, we discuss the conflicting and fragmented information on protein aggregation, oxidative damage, and fibrosis. These are fields of study that are integrally tied to anterior segment research. Our goal is to highlight the vital need for Wilson's consilience and unity of knowledge which in turn should lead to enhanced rigor and reproducibility, and most importantly, to greater understanding and not simply knowing., Competing Interests: Conflicts of Interest: Araj H, None., (International Journal of Ophthalmology Press.)

Background Pseudoexfoliation syndrome (PEX) is characterized by a dandruff-like substance in the anterior chamber, composed of various glycoproteins that have an unclear origin. Its deposition is observed on the pupillary margin, lens zonules, and trabecular meshwork. Proteomic studies have identified numerous proteins in the affected individuals, suggesting associations with systemic conditions like heart disease, stroke, and Alzheimer's disease. However, the systemic associations of PEX remain inconclusive, particularly in regions like southern India. Materials and methods A cross-sectional study was conducted on 114 participants. Pseudoexfoliation was graded as mild, moderate, and severe as per standard photographic grading. Systemic examinations included blood pressure measurements, electrocardiography (ECG), and blood investigations for serum lipid profile, fasting and postprandial blood sugar levels, and serum C-reactive protein levels. Small incision cataract surgery was performed for all the patients. Intraoperative complications and postoperative status were recorded. Results Thirty-eight patients (33.3%) had mild PEX, 44 (38.6%) had moderate PEX, and 32 (28.1%) had severe PEX. Hypertension was present in 54 participants (47.4%), diabetes in 21 (18.4%), coronary artery disease in nine (7.9%), and cerebrovascular accidents in three (2.6%). The mean systolic blood pressure was 140.39 mmHg and the mean diastolic blood pressure was 90.37 mmHg. Systolic blood pressure exceeded 140 mmHg in 29 participants (90.6%) with severe PEX, while diastolic blood pressure surpassed 90 mmHg in 26 participants with severe PEX, both with a p-value of 0.001. Mean fasting and postprandial blood sugar levels were 103.80 ± 31.81 mg/dl and 131.72 ± 48.24 mg/dl, respectively. Serum lipid profiles showed mean low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), cholesterol, and triglyceride levels of 103.00 ± 34.49 mg/dl, 29.04 ± 15.51 mg/dl, 172.73 ± 43.34 mg/dl, and 129.33 ± 64.65 mg/dl respectively. Electrocardiographic results indicated that 54 participants (47.37%) had abnormal ECG including rate abnormality in 13.2%, conduction defects in 12.3%, ischemic changes in 10.5%, and structural defects in 11.4%. Eighty-seven percent of patients had non-dilating pupils and iris atrophy, 13.2% had zonular dialysis and intraoperatively, 78% had capsulorhexis extension, 49.12% had difficult nucleus prolapse, and 28.95% had posterior capsular rent. Conclusion This study highlights the significantly elevated parameters of systemic vascular diseases in PEX patients, like elevated blood pressure and more frequent cardiac anomalies, emphasizing the need for comprehensive systemic evaluation and careful preoperative assessment for ocular comorbidities., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. BLDE (Deemed to be University) Institutional Ethical Committee issued approval BLDE (DU)/IEC/687/2022-23. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Patil et al.)

During vertebrate embryonic development, a population of dorsal neural tube-derived stem cells, termed the neural crest (NC), undergo a series of morphogenetic changes and extensive migration to become a diverse array of cell types. Around the developing eye, this multipotent ocular NC cell population, called the periocular mesenchyme (POM), comprises migratory mesenchymal cells that eventually give rise to many of the elements in the anterior of the eye, such as the cornea, sclera, trabecular meshwork, and iris. Molecular cell biology and genetic analyses of congenital eye diseases have provided important information on the regulation of NC contributions to this area of the eye. Nevertheless, a complete understanding of the NC as a contributor to ocular development remains elusive. In addition, positional information during ocular NC migration and the molecular pathways that regulate end tissue differentiation have yet to be fully elucidated. Further, the clinical challenges of ocular diseases, such as Axenfeld-Rieger syndrome (ARS), Peters anomaly (PA) and primary congenital glaucoma (PCG), strongly suggest the need for better treatments. While several aspects of NC evolution have recently been reviewed, this discussion will consolidate the most recent current knowledge on the specification, migration, and contributions of the NC to ocular development, highlighting the anterior segment and the knowledge obtained from the clinical manifestations of its associated diseases. Ultimately, this knowledge can inform translational discoveries with potential for sorely needed regenerative therapies.

Assembly of the ocular anterior segment (AS) is a critical event during development of the vertebrate visual system. Failure in this process leads to anterior segment dysgenesis (ASD), which is characterized by congenital blindness and predisposition to glaucoma. The anterior segment is largely formed via a neural crest-derived population, the Periocular Mesenchyme (POM). In this study, we aimed to characterize POM behaviors and transcriptional identities during early establishment of the zebrafish AS. Two-color fluorescent in situ hybridization suggested that early AS associated POM comprise of a heterogenous population. In vivo and time-course imaging analysis of POM distribution and migratory dynamics analyzed using transgenic zebrafish embryos (Tg[foxc1b:GFP], Tg[foxd3:GFP], Tg[pitx2:GFP], Tg[lmx1b.1:GFP], and Tg[sox10:GFP]) revealed unique AS distribution and migratory behavior among the reporter lines. Based on fixed timepoint and real-time analysis of POM cell behavior a comprehensive model for colonization of the zebrafish AS was assembled. Furthermore, we generated single cell transcriptomic profiles (scRNA) from our POM reporter lines and characterized unique subpopulation expression patterns. Based on scRNA clustering analysis we observed cluster overlap between neural crest associated (sox10/foxd3), POM (pitx2) and finally AS specified cells (lmx1b, and foxc1b). scRNA clustering also revealed several novel markers potentially associated with AS development and/or function including lum, fmoda, adcyap1b, tgfbi, and hmng2. Taken together, our data indicates that AS-associated POM, or Anterior Segment Mesenchyme (ASM), is not homogeneous but rather comprised of several subpopulations with differing colonization patterns, migration behavior, and transcriptomic profiles.

Purpose: The aim of this study was to present an experimental optical coherence tomography (OCT)–guided anterior segment (AS) imaging chick embryo model. Through this model, we aimed to reveal similarities and differences between human cornea, AS tissues, and chick embryo tissues by quantitative image analysis. Methods: Ex vivo, the chick embryos' globes were determined by detailed AS camera of spectral-domain (SD)-OCT in 10 fertilized specific pathogen-free eggs on the 20th day. Quantitative image analysis of anterior chamber tissues was performed with SD-OCT in detail. After imaging, cross sections of the chick embryo globes containing cornea with anterior chamber were histologically examined and compared with human tissues. The similarities of our model with data in the human cornea and AS studies in the literature were compared. Results: SD-OCT imaging was able to successfully delineate the AS tissues of chick embryos such as the cornea, iris, lens, pupil, conjunctiva, ciliary body, anterior chamber, and lens. Quantitative semi-automated measurements showed the following: mean central corneal thickness: 213.4 ± 7.05 μm (197–223 μm), mean anterior chamber depth: 878.9 ± 41.74 (804–919 μm), mean anterior chamber area: 2.43 ± 0.16 mm2 (2.17–2.73 mm2), mean corneoscleral junction (limbal) thickness: 322.8 ± 20.05 μm (289–360 μm), and mean iris thickness: 230.4 ± 13.27 μm (203–245 μm). In addition, detailed histological comparisons of the AS tissues with human tissues were evaluated to be very similar. Conclusion: In conclusion, this chick embryo model mimics human tissues and it can be considered as a platform for the study of teratogen-induced malformations and AS dysgenesis during gestation of AS tissues. In addition, this study demonstrates the feasibility of SD-OCT in the quantitative assessment of AS structures in chick embryo model.

Abstract Background Optical coherence tomography angiography (OCTA) is a novel non-invasive angiography technology that has recently been extensively studied for its utility in anterior segment imaging. In this study, we compared a split-spectrum amplitude decorrelation angiography (SSADA) OCTA and an optical micro-angiography (OMAG SD) OCTA system to current angiographic technique, indocyanine green angiography (ICGA), to assess corneal vascularisation in an animal model. Methods We imaged 16 rabbits, (one eye per animal) with corneal vascularisation using SSADA OCTA (AngioVue; Optovue Inc., USA), OMAG OCTA (Angioscan; RS-3000 Nidek Co. Ltd., Japan) and ICGA in the same region of interest of the cornea at successive time-points. We then analysed all scanned images for vessel density measurements and used paired t-tests and Bland-Altman plots to examine for significant differences. The en-face segmentation images from each of the OCTA scans were also extracted and were matched at every 50 μm segmentation to be compared for vessel density at the respective depths. Results Bland-Altman plots revealed a good agreement between all three imaging techniques (P > 0.05) for all vessel density measurements computed, and the ranges of 95% limit of agreement were acceptable from a clinical perspective. No significant difference was reported, with ICGA (μ = 16.52 ± 8.94%) being more comparable to the OMAG OCTA (μ = 16.23 ± 9.51%; p = 0.50) than the SSADA OCTA (μ = 17.09 ± 7.34%; p = 0.33) system. Also, a good correlation value (r > 0.9) was obtained when comparing the vessel density measurements of the en-face segmentations between the OCTA systems. Conclusions Comparable vessel density quantification between the two OCTA systems, and with ICGA was obtained. Segmentation analysis of the vasculature at different depths showed varied performance in the two OCTA systems relative to each other. The implications of the study may help to aid in the development of better OCTA algorithms for the anterior segment and its use in clinical translational research.

Purpose The aim of this study was to evaluate the changes in anterior segment parameters by ultrasound biomicroscopy (UBM) after laser peripheral iridotomy (LPI) in eyes with narrow drainage angles. Patients and methods A prospective study was conducted on 20 eyes of 20 different patients with primary angle-closure glaucoma in need for LPI. Patients underwent a detailed ophthalmic examination including slit lamp examination, intraocular pressure measurement, and gonioscopy. UBM was performed before and 1 week after LPI. Quantitative parameters included angle-opening distance (AOD), iris thickness, trabecular-iris angle, trabecular-ciliary process distance, iris-lens contact distance (ILCD), and iridocorneal angle recess area (ICA). Results The mean age of the patients was 55±9.6 years (range: 40–80 years), and 12 patients were females. LPI was performed in the supero-temporal quadrant in 12 eyes and in the supero-nasal quadrant in eight eyes. On gonioscopy, none of the angle structures were seen on primary gaze in the four quadrants in two eyes, in three quadrants in eight eyes, and in two quadrants in 10 eyes. After LPI, ILCD increased significantly in 10 eyes (P

Abstract Background Spectral domain optical coherence tomography (SD-OCT) was a useful tool to study accommodation in human eye, but the maximum image depth is limited due to the decreased signal-to-noise ratio (SNR). In this study, improving optical resolutions, speeds and the SNR were achieved by custom built SD-OCT, and the evaluation of the impact of the improvement during accommodation was investigated. Methods Three systems with different spectrometer designs, including two Charge Coupled Device (CCD) cameras and one Complementary Metal-Oxide-Semiconductor Transistor (CMOS) camera, were tested. We measured the point spread functions of a mirror at different positions to obtain the axial resolution and the SNR of three OCT systems powered with a light source with a 50 nm bandwidth, centered at a wavelength of 840 nm. Two normal subjects, aged 26 and 47, respectively, and one 75-year-old patient with an intraocular lens implanted were imaged. Results The results indicated that spectrometers using cameras with 4096 camera pixels optimized the axial resolutions, due to the use of the full spectrum provided by the light source. The CCD camera system with 4096 pixels had the highest SNR and the best image quality. The system with the CMOS camera with 4096 pixels had the highest speed but had a compromised SNR compared to the CCD camera with 4096 pixels. Conclusions Using these three OCT systems, we imaged the anterior segment of the human eye before and after accommodation, which showed similar results among the different systems. The system using the CMOS camera with an ultra-long scan depth, high resolution and high scan speed exhibited the best overall performance and therefore was recommended for imaging real-time accommodation.

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Introduction:The present study aimed to compare the anterior segment measurements between optical low-coherence reflectometry (LenStar LS900) and anterior segment optical coherence tomography (CASIA2 OCT). Methods:A total of 198 right eyes of 198 healthy participants were used for the current study, according to the inclusion and exclusion criteria. Ocular biometry parameters, such as central corneal thickness (CCT), anterior chamber depth (ACD), keratometry, and anterior chamber width (ACW), were measured usingLenStar LS 900 and CASIA2 OCT. The differences and correlations were assessed between these two instruments. The agreement was calculated as the 95% limits of agreement (LoA). Results: Among 198 subjects with a mean age of 29.39±7.88 years who enrolled in the study, 106 individuals (53.5%) were women. The mean CCT values were 531.7±35.25 and 527.3±37.82 µm for LenStar and OCT, respectively (P=0.0001). The ACD measurements showed 2.92±0.40 and 2.95±0.43 mm for LenStar and OCT, respectively (P=0.0549). The ACW mean values were 12.04±0.52 and 11.79±0.49 mm by LenStar and OCT (P=0.0001). The 95% LoA between the two instruments were within the ranges of -20.79 to 29.43 µm, -0.50 to -0.43 mm, -0.32 to 0.82 mm, and -0.70 to 0.87 D for CCT, ACD, ACW, and astigmatism, respectively. Conclusion: LenStar and OCT showed to have interchangeable ACD measurements; however, the results of CCT, ACW, and corneal astigmatism measured by these two instruments demonstrated clinically significant differences. [ABSTRACT FROM AUTHOR]

Background: Human immunodeficiency virus and acquired immunodeficiency syndrome (HIV/AIDS) causes impairment to the immune system, which then leads to immunocompromised conditions, and allows for opportunistic infection to invade many organs of the human body. Ocular involvement is very common; the various ocular complications may be asymptomatic and they may be the initial manifestations of the underlying diseases. Aim: This study aimed to determine the prevalence and the type of ocular manifestations that occur in HIV and AIDS patients. Setting: The study was conducted on ART (antiretroviral treatment) clinic patients in the Department of Ophthalmology at the Steve Biko Academic Hospital, Pretoria. Methods: This descriptive, cross-sectional study was conducted on HIV and AIDS patients referred from the ART clinic for complete ophthalmological evaluation, irrespective of the immune system status and presence or absence of symptoms. All the participants underwent an ophthalmologic evaluation, which included case history and ocular examinations of both anterior and posterior segments. Results: Out of the 177 participants, 72.3% had visual acuity of between 6/3 to 6/18, 10% had poor vision, 7% had lost one eye to ocular complications and 5% were blind. The most common anterior segment manifestations were uveitis and dry eye, whilst HIV-related retinopathy and papilledema were the most prevalent conditions in the posterior segment. Only three participants had third cranial nerve palsy. Conclusion: The prevalence of ocular manifestations was significantly higher with lower CD4+ cell counts, which could be regarded as predictors for the occurrence of ocular morbidity in HIV and AIDS patients. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the pattern of retinal thickness distribution in patients with keratoconus (KCN) and its correlation with disease severity. Methods: For this cross-sectional cohort study, the study subjects with documented keratoconus and normal eyes were prospectively enrolled. All subjects had anterior segment (Pentacam HR) and posterior segment (Spectralis) imaging. Posterior segment imaging by optical coherence tomography included the posterior pole asymmetry analysis map. Data were analyzed with multiple linear regression models and correlation tests to examine the mean and variance of the measured thickness of the retina and its distribution relative to the presence and severity of KCN. Results: A total of 24 subjects with keratoconus (48 eyes) and 14 normal subjects (28 eyes) enrolled in this study. The posterior pole retinal thickness, both superior and inferior hemifields, as well as the overall retinal thickness in KCN patients was greater than the control group. There was a direct correlation between the overall retinal thickness of the posterior pole and the severity of KCN (R2 = 0.422, P < 0.001). However, the variability of the retinal thickness showed no difference between KCN-afflicted and healthy eyes. Conclusion: Although KCN is a disease of the anterior segment of the eye, we found an orderly increase in posterior pole retinal thickness that is correlated with the severity of disease in KCN eyes compared to control. These findings suggest that the retina may maintain some degree of plasticity to respond to the degraded optical system of the eye. [ABSTRACT FROM AUTHOR]

Objective: To determine the vascular density of the anterior segment (AS) of the eye from optical coherence tomography angiography (OCTA) images and slit-lamp photographs. Methods: A swept-source OCTA (Plex Elite 9000; Carl Zeiss) device modified with a +10-diopter lens was used to record the vasculature of the AS. Twenty eyes, including 4 eyes of 4 healthy subjects and 16 eyes of 12 patients scheduled for cataract surgery or combined vitrectomy and cataract surgery, were studied. The slit-lamp photographs of the AS were acquired concurrently with the AS-OCTA images. The vascular density was measured preoperatively and postoperatively in the nasal, temporal, superior, and inferior quadrants after binarization with ImageJ software. Results: Acceptable AS-OCTA images were obtained of 65% (superior), 80% (nasal), 70% (inferior), and 80% (temporal) of the eyes. The percentage of acceptable images was significantly lower in the superior quadrant among the AS-OCTA images than among the AS photographs (100%; p = 0.004). The vascular density determined by AS-OCTA was higher than that determined in the AS photographs in all quadrants (p = 0.011 to <0.001). The AS-OCTA B-mode images showed that vascular flow was identified mainly between the conjunctiva and sclera but not in the ciliary body. The vascular density increased significantly after cataract surgery in the superior quadrant, which was significantly correlated with the location of the surgical incision (p = 0.03). Conclusion: AS-OCTA can obtain images with higher vascular density of the conjunctiva and sclera than slit-lamp photographs, and AS-OCTA images can show a postoperative increase in vascular density. [ABSTRACT FROM AUTHOR]

To assess the repeatability of several anterior segment parameters obtained with swept-source optical coherence tomography (SS-OCT). We measured 5-times consequently several parameters in 69 eyes using the ANTERION SS-OCT. White-to-white (WTW), angle-to-angle (ATA), spur-to-spur (STS), and lens vault distances were measured in the horizontal- and vertical-meridian. Anterior-chamber-angle (ACA), scleral-spur-angle (SSA), angle-opening-distance (AOD), and trabecular-iris-space-area (TISA) were measured at 500 and 750 μm for the superior-, nasal-,inferior-, and temporal-quadrants. Intrasubject standard deviation (Sw),coefficient of variation (CoV), coefficient of repeatability (CoR), and intraclass-correlation-coefficient (ICC) were calculated for each parameter. Bland-Altman analysis was done. We have not found statistically significant differences between repeated measurements (p > 0.05). Repeatability was good for the different parameters evaluated. Sw values in distances and areas were low and ranged from 0.01 to 0.07. CoR values showed a similar pattern being larger for those metrics measuring angles. The same happened with CoV values, being very small for WTW,ATA, and STS distances (0.16–0.57%). ICC values for all parameters analyzed were > 0.97. Bland-Altman plots evidenced the narrow limits of agreement for all parameters. The ANTERION SS-OCT demonstrated high repeatability measuring different distances, angles, and areas of the anterior segment of the eye. [ABSTRACT FROM AUTHOR]

To assess the repeatability of ocular biometric parameters using a high-resolution imaging device. 74 healthy right eyes were included in this study. Five-repeated measurements were taken with ANTERION high-resolution swept-source optical coherence tomographer (SS-OCT) to measure: corneal thickness (central and at 2, 4 and 6-mm diameters), aqueous depth (AD), lens thickness (LT), anterior chamber volume (ACV), axial length (AL), and pupil (diameter and position). The intrasubject standard deviation (Sw), coefficient of repeatability (CoR) and intraclass correlation coefficient (ICC) were calculated. Bland-Altman method was applied to analyze the difference between the first and the last measurement. The average and the difference between both measurements were calculated for all parameters. We have not found statistically significant differences between repeated measurements (p > 0.05). The mean difference for corneal thickness was between −0.08 and 0.28 μm. For AD and LT was 0.004 and −0.004 μm, respectively. ACV mean difference was −0.03 mm3 and for AL was 0.001 mm. Pupil diameter and position mean differences ranged between −0.008 and 0.009 mm. Overall, most ocular parameters had a Sw <1 and a CoR <2 in their respective units, and an ICC >0.92. The ANTERION high-resolution SS-OCT device provides good repeatability for different ocular biometric measurements. [ABSTRACT FROM AUTHOR]

Purpose: To define diurnal changes in anterior segment parameters of keratoconus patients by using Scheimpflug imaging. Methods: All keratoconus patients had corneal topography measurements 3 times a day (around 09:00 AM, 13:00 PM and 17:00 PM) by the same experienced operator. Three consecutive scans in each measurement session were obtained. The average of three measurements was used for analysis. A repeated measures analysis of variance with one within-subject factor (time of day) was carried out to assess diurnal variation. Results: This study included 26 eyes of 26 patients with keratoconus. Significant diurnal variation was found in CCT and TCT measurements (P < 0.01, and P < 0.01, respectively). The mean amplitudes of change in CCT and TCT were 4.2 ± 1 µm (95% CI: 1.7–6.8 µm) and 4.1 ± 1.1 µm (95% CI: 1.2–8.0 µm), while the mean of CCT and TCT were 462.4 ± 34.5 µm (95% CI: 448.4–476.6 µm) and 452.9 ± 6.6 µm (95% CI: 439.3–466.5 µm), respectively. The maximum value and the lowest value were observed at 09:00 AM and at 17:00 PM, respectively. Other parameters except CCT and TCT did not show diurnal variation. Conclusion: Statistically significant but clinically insignificant diurnal variation in CCT and TCT measurements of the keratoconus patients were detected over an 8-hour period (09:00 AM–17:00 PM). [ABSTRACT FROM AUTHOR]