Comparing generative and retrieval-based chatbots in answering patient questions regarding age-related macular degeneration and diabetic retinopathy.

BACKGROUND/AIMS: To compare the performance of generative versus retrieval-based chatbots in answering patient inquiries regarding age-related macular degeneration (AMD) and diabetic retinopathy (DR). METHODS: We evaluated four chatbots: generative models (ChatGPT-4, ChatGPT-3.5 and Google Bard) and a retrieval-based model (OcularBERT) in a cross-sectional study. Their response accuracy to 45 questions (15 AMD, 15 DR and 15 others) was evaluated and compared. Three masked retinal specialists graded the responses using a three-point Likert scale: either 2 (good, error-free), 1 (borderline) or 0 (poor with significant inaccuracies). The scores were aggregated, ranging from 0 to 6. Based on majority consensus among the graders, the responses were also classified as 'Good', 'Borderline' or 'Poor' quality. RESULTS: Overall, ChatGPT-4 and ChatGPT-3.5 outperformed the other chatbots, both achieving median scores (IQR) of 6 (1), compared with 4.5 (2) in Google Bard, and 2 (1) in OcularBERT (all p ≤8.4×10-3). Based on the consensus approach, 83.3% of ChatGPT-4's responses and 86.7% of ChatGPT-3.5's were rated as 'Good', surpassing Google Bard (50%) and OcularBERT (10%) (all p ≤1.4×10-2). ChatGPT-4 and ChatGPT-3.5 had no 'Poor' rated responses. Google Bard produced 6.7% Poor responses, and OcularBERT produced 20%. Across question types, ChatGPT-4 outperformed Google Bard only for AMD, and ChatGPT-3.5 outperformed Google Bard for DR and others. CONCLUSION: ChatGPT-4 and ChatGPT-3.5 demonstrated superior performance, followed by Google Bard and OcularBERT. Generative chatbots are potentially capable of answering domain-specific questions outside their original training. Further validation studies are still required prior to real-world implementation.

Relationship Between Retinal Layer Thickness and Genetic Susceptibility to Age-Related Macular Degeneration in Asian Populations.

Purpose: For OCT retinal thickness measurements to be used as a prodromal age-related macular degeneration (AMD) risk marker, the 3-dimensional (3D) topographic variation of the relationship between genetic susceptibility to AMD and retinal thickness needs to be assessed. We aimed to evaluate individual retinal layer thickness changes and topography at the macula that are associated with AMD genetic susceptibility. Design: Genetic association study. Participants: A total of 1579 healthy participants (782 Chinese, 353 Malays, and 444 Indians) from the multiethnic Singapore Epidemiology of Eye Diseases study were included. Methods: Spectral-domain OCT and automatic segmentation of individual retinal layers were performed to produce 10 retinal layer thickness measurements at each ETDRS subfield, producing 3D topographic information. Age-related macular degeneration genetic susceptibility was represented via single nucleotide polymorphisms (SNPs) and aggregated via whole genome (overall) and pathway-specific age-related macular degeneration polygenic risk score (PRSAMD). Main Outcome Measures: Associations of individual SNPs, overall PRSAMD, and pathway-specific PRSAMD with retinal thickness were analyzed by individual retinal layer and ETDRS subfield. Results: CFH rs10922109, ARMS2-HTRA1 rs3750846, and LIPC rs2043085 were the top AMD susceptibility SNPs associated with retinal thickness of individual layers (P < 1.67 × 10-3), all at the central subfield. The overall PRSAMD was most associated with thinner L9 (outer segment photoreceptor/retinal pigment epithelium complex) thickness at the central subfield (ß = -0.63 µm; P = 5.45 × 10-9). Pathway-specific PRSAMD for the complement cascade (ß = -0.53 µm; P = 9.42 × 10-7) and lipoprotein metabolism (ß = -0.05 µm; P = 0.0061) were associated with thinner photoreceptor layers (L9 and L7 [photoreceptor inner/outer segments], respectively) at the central subfield. The mean PRSAMD score was larger among Indians compared with that of the Chinese and had the thinnest thickness at the L9 central subfield (ß = -1.00 µm; P = 2.91 × 10-7; R2 = 5.5%). Associations at other retinal layers and ETDRS regions were more heterogeneous. Conclusions: Overall genetic susceptibility to AMD and the aggregate effects of the complement cascade and lipoprotein metabolism pathway are associated most significantly with L7 and L9 photoreceptor thinning at the central macula in healthy individuals. Photoreceptor thinning has potential to be a prodromal AMD risk marker, and topographic variation should be considered. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Ultrasound Assessment of Gaze-induced Posterior Eyewall Deformation in Highly Myopic Eyes.

Purpose: To establish a quantitative metric of posterior eyewall deformability in different directions of gaze in highly myopic eyes with and without posterior staphyloma. Methods: A prospective study was performed on 53 highly myopic patients (106 eyes). Ultrasound scans were acquired in primary, up, downward, nasal, and temporal gazes. A validated intensity-based segmentation algorithm was used to quantify the posterior eyewall geometry on digitalized B-scan images. Posterior eyewall local curvature (K) and distance (L) to the transducer were calculated. The associations between directions of gaze, axial length (AL), and presence of staphyloma with the K and L parameters were assessed. Results: A total of 53 participants (106 eyes) were studied. Multivariate regression analysis demonstrated that, after accounting for longer AL, and presence of staphyloma, eccentric gaze was often independently associated with various K and L parameters. Specifically, downward gaze was associated with increased posterior eyewall concavity as reflected in the maximum of K (KMax) (ß = 0.050, P < 0.001) and absolute value of KMax (ß = 0.041, P = 0.011). Both downward gaze and upgaze were independently associated with increase in the derivative of absolute KMax (which is consistent with more apparent, steeper staphyloma ridges), local KMax (which detects KMax at smaller intervals), and Kstd (which represents likelihood of staphyloma presence) and decrease in maximum of L (which represents movement of the staphyloma apex) with all P < 0.05. The ß coefficients for downward gaze were consistently greater in magnitude compared with those in upgaze. After accounting for AL and presence of staphyloma, horizontal gazes were independently associated only with decrease in the standard deviation of L (which also represents likelihood of staphyloma presence) and maximum of L. Conclusions: Downward gaze results in a significant increase in posterior eyewall concavity in highly myopic eyes after accounting for AL and staphyloma presence. In comparison with downward gaze, upgaze resulted in a lower magnitude, but significant changes in staphyloma ridge steepness and the likelihood of staphyloma presence. Horizontal gazes seemed to be associated with less posterior eyewall geometric parameters. Studies are required to further assess the association between downward gaze during near work on posterior eyewall concavity and possible effects on myopia development and progression.

Optical Coherence Tomography Angiography in Retinal Vascular Disorders.

Traditionally, abnormalities of the retinal vasculature and perfusion in retinal vascular disorders, such as diabetic retinopathy and retinal vascular occlusions, have been visualized with dye-based fluorescein angiography (FA). Optical coherence tomography angiography (OCTA) is a newer, alternative modality for imaging the retinal vasculature, which has some advantages over FA, such as its dye-free, non-invasive nature, and depth resolution. The depth resolution of OCTA allows for characterization of the retinal microvasculature in distinct anatomic layers, and commercial OCTA platforms also provide automated quantitative vascular and perfusion metrics. Quantitative and qualitative OCTA analysis in various retinal vascular disorders has facilitated the detection of pre-clinical vascular changes, greater understanding of known clinical signs, and the development of imaging biomarkers to prognosticate and guide treatment. With further technological improvements, such as a greater field of view and better image quality processing algorithms, it is likely that OCTA will play an integral role in the study and management of retinal vascular disorders. Artificial intelligence methods-in particular, deep learning-show promise in refining the insights to be gained from the use of OCTA in retinal vascular disorders. This review aims to summarize the current literature on this imaging modality in relation to common retinal vascular disorders.

New Concepts for the Diagnosis of Polypoidal Choroidal Vasculopathy.

Polypoidal choroidal vasculopathy (PCV) is a subtype of neovascular age-related macular degeneration (nAMD) that is characterized by a branching neovascular network and polypoidal lesions. It is important to differentiate PCV from typical nAMD as there are differences in treatment response between subtypes. Indocyanine green angiography (ICGA) is the gold standard for diagnosing PCV; however, ICGA is an invasive detection method and impractical for extensive use for regular long-term monitoring. In addition, access to ICGA may be limited in some settings. The purpose of this review is to summarize the utilization of multimodal imaging modalities (color fundus photography, optical coherence tomography (OCT), OCT angiography (OCTA), and fundus autofluorescence (FAF)) in differentiating PCV from typical nAMD and predicting disease activity and prognosis. In particular, OCT shows tremendous potential in diagnosing PCV. Characteristics such as subretinal pigment epithelium (RPE) ring-like lesion, en face OCT-complex RPE elevation, and sharp-peaked pigment epithelial detachment provide high sensitivity and specificity for differentiating PCV from nAMD. With the use of more practical, non-ICGA imaging modalities, the diagnosis of PCV can be more easily made and treatment tailored as necessary for optimal outcomes.

Review of Retinal Imaging Modalities for Hydroxychloroquine Retinopathy.

This review provides an overview of conventional and novel retinal imaging modalities for hydroxychloroquine (HCQ) retinopathy. HCQ retinopathy is a form of toxic retinopathy resulting from HCQ use for a variety of autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. Each imaging modality detects a different aspect of HCQ retinopathy and shows a unique complement of structural changes. Conventionally, spectral-domain optical coherence tomography (SD-OCT), which shows loss or attenuation of the outer retina and/or retinal pigment epithelium-Bruch's membrane complex, and fundus autofluorescence (FAF), which shows parafoveal or pericentral abnormalities, are used to assess HCQ retinopathy. Additionally, several variations of OCT (retinal and choroidal thickness measurements, choroidal vascularity index, widefield OCT, en face imaging, minimum intensity analysis, and artificial intelligence techniques) and FAF techniques (quantitative FAF, near-infrared FAF, fluorescence lifetime imaging ophthalmoscopy, and widefield FAF) have been applied to assess HCQ retinopathy. Other novel retinal imaging techniques that are being studied for early detection of HCQ retinopathy include OCT angiography, multicolour imaging, adaptive optics, and retromode imaging, although further testing is required for validation.

FIVE-YEAR INCIDENCE OF FELLOW EYE NEOVASCULAR INVOLVEMENT IN AGE-RELATED MACULAR DEGENERATION AND POLYPOIDAL CHOROIDAL VASCULOPATHY IN AN ASIAN POPULATION.

PURPOSE: To assess 5-year cumulative incidence and risk factors of fellow eye involvement in Asian neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy. METHODS: In a prospective cohort study of Asian nAMD and polypoidal choroidal vasculopathy, the fellow eyes were evaluated for exudation. The 5-year incidence of exudation was compared between nAMD and polypoidal choroidal vasculopathy. RESULTS: A total of 488 patients were studied. The 5-year incidence of exudation in fellow eyes was 16.2% (95% confidence interval: 12.0-20.2). Polypoidal choroidal vasculopathy compared with nAMD in the first eye was associated with lower fellow eye progression (9.8% [95% confidence interval: 5.1-14.3]) vs. 22.9% [95% confidence interval: 15.8-29.3], P < 0.01). Drusen (hazards ratio 2.11 [95% confidence interval: 1.10-4.06]), shallow irregular retinal pigment epithelium elevation (2.86 [1.58-5.18]), and pigment epithelial detachment (3.01 [1.27-7.17]) were associated with greater progression. A combination of soft drusens and subretinal drusenoid deposits, and specific pigment epithelial detachment subtypes (multilobular, and sharp peaked) were associated with progression. Pigment epithelial detachment, shallow irregular retinal pigment epithelium elevation, and new subretinal hyperreflective material occurred at 10.4 ± 4.2 months, 11.1 ± 6.0 months, and 6.9 ± 4.3 months, respectively, before exudation. CONCLUSION: The 5-year incidence of fellow eye involvement in Asian nAMD is lower than among Caucasians because of a higher polypoidal choroidal vasculopathy prevalence. Drusens, shallow irregular retinal pigment epithelium elevation, and pigment epithelial detachment are risk factors for fellow eye progression.

PATTERN AND CHARACTERISTICS OF DRUSEN SUBTYPES IN CHINESE AND INDIAN POPULATIONS IN SINGAPORE.

PURPOSE: To report the pattern and characteristics of drusen subtypes in Asian populations and the association with choroidal thickness. METHODS: This is the cross-sectional analysis of the population-based cohort study. Two thousand three hundred and fifty-three eyes of 1,336 Chinese and Indian participants aged older than 50 years, eyes with best-corrected visual acuity better than 20/60, and without other retinal diseases were recruited. Pachydrusen, reticular pseudodrusen, soft and hard drusen were graded on both color fundus photographs, and optical coherence tomography imaging with automated segmentation yielding and measurements of choroidal thickness. RESULTS: Nine hundred and fifty-five Chinese and 381 Indians were included in the final analysis. The pattern of pachydrusen, soft drusen, hard drusen, and reticular pseudodrusen was 14.0%, 3.7%, 12.5%, and 0.2%, respectively. Mean choroidal thickness was the thickest in eyes with pachydrusen (298.3 µm; 95% confidence interval: 290.5-306.1), then eyes with hard (298.1 µm; 95% confidence interval: 290.6-305.5) and soft drusen (293.7 µm; 95% confidence interval: 281.9-305.4) and thinnest in eyes without drusen (284.6 µm; 95% confidence interval: 280.5-288.7). Systemic associations of the various drusen subtypes also differed. CONCLUSION: Patterns, characterization and choroidal thickness of drusen subtypes, and their associations provide insights into the Asian phenotypic spectrum of age-related macular degeneration and the underlying pathogenesis.

Review of Fibrosis in Neovascular Age-Related Macular Degeneration.

PURPOSE: To report the diagnosis and definitions, epidemiology, risk factors, and visual outcomes of fibrosis in neovascular age-related macular degeneration (nAMD). DESIGN: Systematic review and meta-analysis. METHODS: The review was performed using the Cochrane Handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Observational studies and randomized controlled trials were included. RESULTS: Identification of fibrosis is challenging. Optical coherence tomography angiography and polarization-sensitive optical coherence tomography represent novel options in multimodal imaging. The prevalence of fibrosis at baseline, 12, 24, and 60 months was 13%, 32%, 36%, and 56%, respectively. Approximately 60% of the fibrosis burden in nAMD at 5 years was present in the first year of treatment. Fibrosis development was highest in the first 12 months and slowed down over time. The risk factors of fibrosis included classic choroidal neovascularization (CNV), intra-retinal fluid, hemorrhage, hyperreflective material, CNV lesion size, and retinal thickness. Sub-retinal fluid and pigment epithelial detachment may be protective. Treatment-associated factors included disease activity and time to diagnosis. At baseline, the best corrected visual acuity in eyes with fibrosis was poorer than in eyes without fibrosis (-18.50 letters); this difference became larger at 12 months despite treatment (-26.86 letters). CONCLUSIONS: There is a need to identify effective treatment strategies for fibrosis and to closely monitor at-risk patients. More studies involving multimodal imaging are required to clarify the definitions and grading criteria for fibrosis.

Quantitative assessment of the choroidal vasculature in myopic macular degeneration with optical coherence tomographic angiography.

Background: To assess and compare choroidal morphometric vascular parameters, using optical coherence tomographic angiography (OCTA), in highly myopic adults with and without myopic macular degeneration (MMD). Methods: This is a clinic-based observational study of 148 eyes with axial length (AL) ≥25mm, enrolled from the high myopia clinic of the Singapore National Eye Centre. MMD was graded from fundus photographs. Swept source OCT (SS-OCT) and OCTA were performed and assessed for choroidal layer thickness (CT) and choroidal vasculature (choroidal vessel density (CVD), choroidal branch area (CBA) and mean choroidal vessel width (MCVW)) in the different choroidal layers (overall choroidal layer (CL), medium-vessel choroidal layer (MVCL), large-vessel choroidal layer (LVCL)). Results: CTCL (r=-0.58, p<0.001), CTMVCL (r=-0.22, p=0.04), MCVWCL (r=-0.58, p<0.001), and CVDCL (r=-0.19, p=0.02) were negatively correlated with AL, while CBACL (r=0.61, p<0.001) was positively correlated. Compared to eyes with no MMD, eyes with MMD2 had lower CTCL (120.37±47.18µm vs 218.33±92.70µm, p<0.001), CTMVCL (70.57±15.28µm vs 85.32±23.71µm, p=0.04), CTLVCL (101.65±25.36µm vs 154.55±68.41µm, p=0.001) and greater CVDCL (71.10±3.97% vs 66.97±3.63%, p<0.001), CVDMVCL (66.96±2.35% vs 65.06±2.69%, p=0.002), CVDLVCL (68.36±2.56% vs 66.58±2.88%, p=0.012), MCVWMVCL (6.14±0.34µm vs 5.90±0.35µm, p=0.007), and CBACL (12.69±1.38% vs 11.34±1.18%, p<0.001). After adjusting for age, thicker CTCL (odds ratio (OR) 0.98, 95% confidence interval (CI) 0.97-0.99, p<0.001), CTMVCL (OR 0.97 (0.94-0.99), p=0.002) and CTLVCL (OR 0.97 (0.96-0.98, p<0.001) were significantly associated with lower odds of MMD2, while increased CVDCL (OR 1.37 (1.20-1.55), p<0.001), CVDMVCL (OR 1.39 (1.12-1.73), p=0.003), CVDLVCL (OR 1.31 (1.07-1.60), p=0.009), CBACL (OR 2.19 (1.55-3.08), p<0.001) and MCVWMVCL (OR 6.97 (1.59-30.51), p=0.01) was significantly associated with higher odds of MMD2. Conclusion: Decrease in choroidal vessel width, density and thickness, and an increase in vascular branching were observed in eyes with long AL. A thinner and denser choroid with greater branching area and vessel width, which may all be signs of hypoxia, were associated with greater odds of MMD2.

Intraocular Eyelash after an Uneventful Cataract Surgery: Case Report and Literature Review.

The presence of an eyelash in the anterior chamber after an uneventful phacoemulsification and intraocular lens implant surgery is exceedingly rare, with 8 cases reported globally. We present a patient in whom an eyelash was found trapped in the main cornea wound at postoperation week 1 after an uneventful surgery and unremarkable postoperation day 1 review. The eyelash was removed immediately. The patient denied rubbing his eye and there is video evidence of an uneventful surgery with no eyelash in the anterior chamber at the end of the surgery. Interestingly, the orientation of the eyelash supports previous reports that the eyelash tends to migrate intraocularly through the cornea wound in one direction (i.e., with proximal end/follicle first), purportedly due to the cellular arrangement of an eyelash. Management of such cases should be undertaken on a case-by-case basis. The treatment strategy includes observation or prompt removal, either at the slit lamp or at the operating theatre, depending on a few factors including extent of ocular inflammation, time of presentation, eyelash contact with the cornea endothelium, and location of the eyelash. Patients should be reminded not to rub their eyes after cataract surgery.

An evidence-based review of the epidemiology of myopic traction maculopathy.

Myopic traction maculopathy (MTM), one of the complications of pathologic myopia, is a spectrum of pathological conditions that are attributed to tractional changes in the eye characterized by retinoschisis, lamellar or full thickness macular hole, and foveal retinal detachment. Considering the global public health burden of MTM and pathologic myopia, it is important to understand these sight-threatening complications and their associations. We conducted an evidence-based review of the prevalence and natural history of MTM and associated risk factors. The prevalence of MTM in the general population is low, but is increased among high myopes. MTM is associated with preretinal tractional structures, myopic refractive error and axial elongation, posterior staphyloma, dome-shaped macula, chorioretinal atrophy, and myopic macular degeneration. The clinical course of MTM tends to be stable; however, MTM may progress, resulting in visual acuity deterioration, although spontaneous improvement also occurs. The associations of MTM progression include vitreous traction, location, and extent of MTM, and lamellar macular hole-specific factors. More high-quality population-based studies that assess MTM prevalence and natural history are needed.

Three-dimensional modelling of the choroidal angioarchitecture in a multi-ethnic Asian population.

This study aimed to describe the topographic variation of the macula's choroidal angioarchitecture using three-dimensional (3D) choroidal vascularity index (CVI) of healthy eyes from an Asian population and to investigate the associations of CVI. 50 participants were recruited via stratified randomisation based on subfoveal choroidal thickness from the Singapore Epidemiology of Eye Diseases Study. Macular volume scans were acquired using spectral-domain optical coherence tomography with enhanced depth imaging. CVI was assessed based on B-scan binarisation and choroid segmentation. The 3D CVI of the whole, superior, central, and inferior macula were 62.92 ± 1.57%, 62.75 ± 1.93%, 63.35 ± 1.72%, and 62.66 ± 1.70%, respectively, pairwise comparisons P all > 0.05). 3D CVI (Whole Macula) and 2D CVI (Subfoveal) were associated only with each other and not with other ocular and systemic factors. 2D CVI (Subfoveal) had a moderate agreement with 3D CVI (Central Macula) [intraclass corelation coefficient (ICC) = 0.719], and had poorer agreement with 3D CVI of the whole macula, superior, and inferior macula (ICC = 0.591, 0.483, and 0.394, respectively). Scanning volume did not influence 3D CVI measurements. In conclusion, 3D CVI demonstrated no significant topographic variation. CVI was not correlated with demographic or ocular structural features. 2D CVI of the fovea is partially representative of 3D CVI of the macula.

Association between retinal thickness variation and visual acuity change in neovascular age-related macular degeneration.

BACKGROUND: To assess the association between variation in retinal central subfield thickness (CSFT) with best-corrected visual acuity (BCVA) change in patients receiving vascular endothelial growth factor (VEGF) inhibitor therapy for neovascular age-related macular degeneration (nAMD). METHODS: CSFT measurements were obtained from 141 eyes (total 1300 scans). SD of CSFT was calculated. The eyes were categorised into CSFT variation tertiles. Multiple linear regression was used to examine the association between the CSFT tertiles and BCVA change at 12 mo, adjusting for differences in baseline demographic and clinical characteristics. RESULTS: At 12 mo, the mean BCVA of the high CSFT variation group (50.6 letters) was significantly lower than the low and moderate CSFT variation groups (57.5 and 59.8 letters, respectively), P = .02. The adjusted mean BCVA gains were +1.7, +7.2, and +7.8 letters in the high, moderate and low CSFT variation groups, respectively (P = .03). CONCLUSIONS: A greater variation in retinal thickness during VEGF inhibitor therapy for nAMD is associated with a less favourable visual outcome. CSFT stability is useful in prognosticating visual outcomes in VEGF inhibitor therapy for nAMD.

Macular neovascularization in eyes with pachydrusen.

The natural history and clinical significance of pachydrusen is unclear. This study aims to compare the longitudinal changes of eyes with pachydrusen and soft drusen and progression to exudative macular neovascularisation (MNV). Patients with a diagnosis of MNV in one eye only and the fellow eye was selected as the study eye. Study eyes were required to have pachydrusen or soft drusen on fundus photographs and follow up of at least 2 years or until exudative MNV occurred. Systematic grading was performed at baseline and change in drusen area and onset of exudative MNV recorded over the period of follow up. A total of 75 eyes from 75 patients (29 with pachydrusen and 46 with soft drusen) were included. There was no difference in the rate of progression to exudative MNV in the soft and pachydrusen groups (13.3% versus 24.1%, p = 0.38). Pachydrusen, as compared to soft drusen, was associated with polypoidal choroidal vasculopathy subtype (85.7% versus 16.7%, p < 0.01) and the location of exudation was co-localised with soft drusen but not with pachydrusen. There was a higher rate of increase in soft drusen area compared to pachydrusen area (27.7 ± 31.9%/year versus 8.7 ± 12.4%/year respectively, p < 0.01). We found no difference in the proportion of eyes that developed exudative MNV in this study however characterisation of drusen evolution patterns revealed a strong association with exudative MNV subtype.

Choroidal and Retinal Changes After Systemic Adrenaline and Photodynamic Therapy in Non-Human Primates.

Purpose: To determine the tomographic, angiographic, and histologic changes in the choroid and retina of cynomolgus monkeys after systemic adrenaline and verteporfin photodynamic therapy (vPDT). Methods: Six cynomolgus monkeys (12 eyes) were treated with vPDT only (n = 2), adrenaline only for eight weeks (n = 2), adrenaline for eight weeks with vPDT at week 4 (n = 4), and adrenaline for 12 weeks and vPDT at week 8 (n = 4). Spectral-domain optical coherence tomography, angiography, and autofluorescence were performed at baseline and every 14 days thereafter until 28 days after adrenaline therapy or vPDT. Choroid parameters included choroidal thickness (CT) changes and structural changes using semiautomated image binarization. Histology with light and electron microscopy was performed. Results: Adrenaline resulted in subfoveal CT increase at week 4 compared with baseline (3.4%, P = 0.010), with further increase at week 8 (3.9%, P = 0.007). This correlated with choroidal luminal area increase (16.0% at week 8 compared with baseline, P = 0.030). Outer retinal changes included subretinal fluid, ellipsoid zone (EZ) disruption, photoreceptor elongation, and sub/intraretinal bright dots. Hypocyanescent spots surrounded by leakage was observed. Histology showed dilated choroidal vessels, intracytoplasmic vacuoles, and retinal pigment epithelium (RPE) enlarged basal infoldings. The vPDT decreased subfoveal CT at four weeks after vPDT (-7.5%, P = 0.007). This correlated with choroidal stromal area decrease (-18.0%, P < 0.010). Within the treatment spot, there was outer retinal atrophy, EZ disruption, irregular RPE thickening, intense hypoautofluorescence, hyperfluorescence, and hypocyanescence. On histology, there were outer retina, RPE, and choroid changes. Conclusions: Adrenaline induces choroidal vessel dilation and CT increase. The vPDT decreases CT because of a reduction in choroidal stromal component.

Association of SNTB1 with High Myopia.

PURPOSE: To investigate the associations of Single Nucleotide Polymorphisms (SNPs) in the SNTB1 gene with high myopia in a Han Chinese population. MATERIALS AND METHODS: Based on previous studies, four SNPs from the SNTB1 gene were chosen for genotyping. This is a case-control genetic association study comprising 193 high myopia participants and 135 normal emmetropic controls from a Han Chinese population. Allelic frequencies of the SNPs and haplotypes were compared to assess the associations of the SNPs with high myopia and axial length (AL). RESULTS: The SNPs rs7839488 (effect allele: A; OR = 0.685), rs4395927 (effect allele: T; OR = 0.692), and rs6469937 (effect allele: A; OR = 0.683) displayed significant associations with high myopia initially (P = .044, 0.049, and 0.035, respectively), but did not withstand permutation testing (all Ppermutation>0.05). rs6469937 displayed associations with high myopia in the dominant model (AG+AA: OR = 0.609) against GG (reference). rs6469937 was also associated with AL in the dominant model (AG+AA: Beta = -0.58) against GG (reference). The haplotype analysis demonstrated ATGA as the protective haplotype against high myopia, which remained statistically significant in permutation testing (Ppermutation = 0.045). CONCLUSIONS: Our findings are suggestive that SNTB1 is associated with high myopia in a Han Chinese population.

Influence of pigment epithelial detachment on visual acuity in neovascular age-related macular degeneration.

Pigment epithelial detachment (PED), the anatomical separation of the retinal pigment epithelium from the Bruch membrane, is common in many chorioretinal diseases, including neovascular age-related macular degeneration. PED is present in about 30% to 80% of neovascular age-related macular degeneration patients based on the CATT, EXCITE, and VIEW studies. The influence of PED on visual acuity is controversial as a result of inconsistent results reported by various studies. With advances in imaging technologies, it is possible to evaluate not only the presence or absence of PED, but also detailed quantitative parameters, such as height, width, greatest linear diameter, area, volume, and reflectivity within the PED. We performed a comprehensive literature review to evaluate the relationship of PED with visual acuity. In summary, the presence or persistence of a PED may still be compatible with relatively good visual acuity. There is no strong evidence that the presence of a PED or aspects of its morphology has a significant impact on visual acuity. The presence of a PED may be predictive of the need for more regular treatment. More well-designed studies with standardized PED definitions and classifications are needed to evaluate the relationship between PED and visual acuity.

Patterns and Determinants of Choroidal Thickness in a Multiethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study.

PURPOSE: To describe the distribution and determinants of choroidal thickness (CT) in participants in a population study based on spectral-domain (SD)-OCT measurements. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: Ethnic Chinese, Indian, and Malay adults aged more than 50 years without any retinal diseases (e.g., diabetic retinopathy, macular edema, age-related macular degeneration, central serous chorioretinopathy) that might affect the CT were recruited from the Singapore Epidemiology of Eye Diseases Study. METHODS: Choroidal imaging was performed by SD-OCT (Spectralis, Heidelberg Engineering, Heidelberg, Germany) in enhanced depth imaging (EDI) mode. Subfoveal choroidal thickness (SFCT) was measured on the foveal line scan by 2 retinal experts independently (YS and KT), and the average was used in the analyses. In Chinese and Indian cohorts in whom macular raster scans were captured, the manufacturer-supplied research software (Heyex SP-X version 6.4.8.116; Heidelberg Engineering) was used to obtain automated segmentation yielding mean choroidal thickness in each of the 9 ETDRS grid sectors. MAIN OUTCOME MEASURES: Subfoveal choroidal thickness and regional CT in the 9 ETDRS grid sectors. RESULTS: For the SFCT analysis, 2794 eyes of 1619 participants (Chinese, Indian, and Malay ) were included. The mean age was 60.9 years (standard deviation, 7.7), and 797 (49.2%) were male. Mean SFCT was 255.2 µm (standard deviation, 102.6). The normal range of SFCT was 106 to 447 µm (corresponding to 5th and 95th percentile limits of SFCT, respectively). In multivariable models, thinner SFCT was associated with older age, female gender, longer axial length, and Malay (vs. Chinese) ethnicity. In the subset of Chinese and Indian eyes (n = 1842) in whom regional variation was evaluated, the choroid was thickest at the superior and temporal sectors and thinner at the inferior and nasal sectors. CONCLUSIONS: Subfoveal choroidal thickness is influenced by age, gender, and ethnicity along with regional differences even within individual eyes. Subfoveal choroidal thickness also shows a wide range in physiologic limits. These data may be used as a reference in future studies.

POLYPOIDAL CHOROIDAL VASCULOPATHY FEATURES VARY ACCORDING TO SUBFOVEAL CHOROIDAL THICKNESS.

PURPOSE: To evaluate associations between choroidal thickness and features of polypoidal choroidal vasculopathy (PCV) lesions based on multimodal imaging. METHODS: This cross-sectional analysis included treatment-naive PCV eyes from a prospectively recruited observational cohort. Associations between of subfoveal choroidal thickness (SFCT) and qualitative and quantitative morphologic features of PCV lesions on color fundus photographs, indocyanine green and fluorescein angiography, and spectral-domain optical coherence tomography were evaluated. RESULTS: We included 100 eyes with indocyanine green angiography-proven PCV. Subfoveal choroidal thickness showed a bimodal distribution with peaks at 170 µm and 350 µm. There was a significant linear increase in the total lesion area (P-trend = 0.028) and the polypoidal lesion area (P-trend = 0.030 and P-continuous = 0.037) with increasing SFCT. Pairwise comparisons between quartiles showed that the total lesion area (4.20 ± 2.61 vs. 2.89 ± 1.43 mm2, P = 0.024) and the polypoidal lesion area (1.03 ± 1.01 vs. 0.59 ± 0.45 mm2, P = 0.042) are significantly larger in eyes in Q4 (SFCT ≥ 350 µm) than eyes in Q1 (SFCT ≤ 170 µm). Although there was no significant linear trend relating SFCT to best-corrected visual acuity, pairwise comparisons showed that eyes in Q4 (SFCT ≥ 350 µm) have significantly worse vision (0.85 ± 0.63 vs. 0.55 ± 0.27 logMAR, P = 0.030) than eyes in Q2 (SFCT 170-260 µm). CONCLUSION: Total lesion areas and polypoidal lesion areas tend to be larger in eyes with increasing SFCT. Choroidal background may influence the phenotype or progression pattern of PCV.