Application of artificial intelligence in cataract management: current and future directions

The rise of artificial intelligence (AI) has brought breakthroughs in many areas of medicine. In ophthalmology, AI has delivered robust results in the screening and detection of diabetic retinopathy, age-related macular degeneration, glaucoma, and retinopathy of prematurity. Cataract management is another field that can benefit from greater AI application. Cataract is the leading cause of reversible visual impairment with a rising global clinical burden. Improved diagnosis, monitoring, and surgical management are necessary to address this challenge. In addition, patients in large developing countries often suffer from limited access to tertiary care, a problem further exacerbated by the ongoing COVID-19 pandemic. AI on the other hand, can help transform cataract management by improving automation, efficacy and overcoming geographical barriers. First, AI can be applied as a telediagnostic platform to screen and diagnose patients with cataract using slit-lamp and fundus photographs. This utilizes a deep-learning, convolutional neural network (CNN) to detect and classify referable cataracts appropriately. Second, some of the latest intraocular lens formulas have used AI to enhance prediction accuracy, achieving superior postoperative refractive results compared to traditional formulas. Third, AI can be used to augment cataract surgical skill training by identifying different phases of cataract surgery on video and to optimize operating theater workflows by accurately predicting the duration of surgical procedures. Fourth, some AI CNN models are able to effectively predict the progression of posterior capsule opacification and eventual need for YAG laser capsulotomy. These advances in AI could transform cataract management and enable delivery of efficient ophthalmic services. The key challenges include ethical management of data, ensuring data security and privacy, demonstrating clinically acceptable performance, improving the generalizability of AI models across heterogeneous populations, and improving the trust of end-users.

Association Between Perforating Scleral Vessel and Myopic Maculopathy: A Cross-Sectional Study of a Chinese Cohort

Purpose: To investigate the association between perforating scleral vessel (PSV) and different types of myopic maculopathy (MM) in a highly myopic population.Methods: In total, 188 highly myopic eyes (117 participants) were enrolled. Each participant underwent detailed history taking and ocular examinations. Based on fundus photographs and optical coherence tomography, patients were subdivided into the non-MM group and MM group. Based on a new classification system (ATN), MM cases were classified as myopic atrophy maculopathy (MAM), myopic tractional maculopathy (MTM), and myopic neovascular maculopathy (MNM). The number of PSV and the macular choroidal thickness (mChT) were measured.Results: Compared with non-MM group, MM group was characterized by relatively larger age (48.40 vs. 32.34; p < 0.001), longer axial length (AL, 29.72 vs. 27.75, p < 0.001), thinner mChT (52.90 vs. 122.52; p < 0.001), and lower PSV counts (6.73 vs. 9.47, p ≤ 0.001). The non-MM group had higher PSV counts in total area (0–9 mm, 9.47 vs. 6.73, p < 0.001) and perifovea area (3–9 mm, 7.25 vs. 4.71, p < 0.001) compared to the MM group. Univariate and multivariate analyses showed that PSV count had no association with MAM (p = 0.2419) and MTM (p = 0.5678). Total PSV count [odds ratio (OR) 0.78, 95% CI 0.64–0.95, p = 0.0149] and perifovea PSV count (OR 0.80, 95% CI 0.65–0.98, p = 0.0299) were both protective factors for MNM. The stratified analysis revealed that in groups with AL <28 mm, or mChT <50 μm, or mChT ≥100 μm, or eyes with cilioretinal artery, PSV count had no significant association with MNM.Conclusion: Higher PSV counts in perifovea area (3–9 mm centered fovea) and total area (0–9 mm centered fovea) were protective factors for MNM, whereas PSV count had no association with MAM and MTM. These findings may provide novel insights into the mechanisms of pathologic myopia.

Serum Antithyroglobulin Antibody Levels Are Associated with Diabetic Retinopathy among Euthyroid Type 2 Diabetes Patients: A Hospital-Based, Retrospective Study

Background. Previous studies have revealed that the variation of thyroid indicators may be associated with the risk of diabetic retinopathy (DR) among euthyroid type 2 diabetes (T2D) patients. But the specific conclusions are currently inconsistent. Methods. This is a hospital-based retrospective survey. We recruited 1,145 euthyroid T2D patients and checked the thyroid function and fundus photographs. The modified Airlie House classification system was used to categorize the stages of DR. The association between thyroid indicators and different stages of DR was analyzed. Results. We divided free triiodothyronine (FT3) into tertiles and found that the prevalence of mild nonproliferative DR (NPDR) was significantly higher in T2, compared with T1 (32.0% vs. 25.2%, p < 0.05 ). When FT3 was within the level of T2, FT3 could be an independent risk factor for mild NPDR (OR 1.426, 95% CI (1.031, 1.971), p < 0.05 ). In addition, the prevalence of severe NPDR and proliferative DR (PDR) was significantly higher in thyroglobulin antibody (TgAb) positive group (8.8% vs. 4.1%, p < 0.05 ) and vice versa (33.3% vs. 18.4%, p < 0.05 ). TgAb positivity was also an independent risk factor for severe NPDR and PDR (OR 2.212, 95% CI (1.244, 3.934), p < 0.05 ). Conclusions. We hardly observed a significant change in DR risk with the elevation or reduction of serum TSH or thyroid hormone within the reference interval. Although the slightly elevated FT3 may be associated to mild NPDR, the extensibility of this result remains to be seen. For T2D patients with euthyroid function, there may be a significant correlation between serum TgAb positivity and severe NPDR and PDR.

Retinal fundus photographs capture hemoglobin loss after blood donation

Recently it was shown that blood hemoglobin concentration could be predicted from retinal fundus photographs by deep learning models. However, it is unclear whether the models were quantifying current blood hemoglobin level, or estimating based on subjects' pretest probability of having anemia. Here, we conducted an observational study with 14 volunteers who donated blood at an on site blood drive held by the local blood center (ie, at which time approximately 10% of their blood was removed). When the deep learning model was applied to retinal fundus photographs taken before and after blood donation, it detected a decrease in blood hemoglobin concentration within each subject at 2-3 days after donation, suggesting that the model was quantifying subacute hemoglobin changes instead of predicting subjects' risk. Additional randomized or controlled studies can further validate this finding.

Retinal Hemorrhage after SARS-CoV-2 Vaccination

To report retinal vein occlusion (RVO) and age-related macular degeneration (AMD)-related submacular hemorrhage developing after administration of SARS-CoV-2 vaccines, a single-center, retrospective observational case series was conducted. Clinical data including fundus photographs and optical coherence tomography (OCT) scans were reviewed. Twenty-three eyes of 21 patients were included with the median age at symptom presentation being 77 years (range: 51–85 years). Twelve eyes (52.2%) had submacular hemorrhage and 11 (47.8%) had RVO. Twelve patients (60.9%) had been vaccinated with the Pfizer vaccine (BNT162b2) and 8 with the AstraZeneca (ChAdOx1) vaccine. Sixteen patients (76.2%) experienced ocular disease exacerbation after the first vaccination and 4 (19.0%) after the second vaccination. The median visual acuity (logarithm of the minimal angle of resolution; logMAR) before symptom development was 0.76 (interquartile range: 0.27–1.23); the median logMAR at symptom presentation was 1.40 (interquartile range 0.52–1.70). The median time between vaccination and symptom exacerbation was 2.0 days (interquartile range: 1.0–3.0 days). Five patients (23.8%) underwent tests for hematological abnormalities, including the presence of anti-PF4 antibodies; all were negative. Further studies with larger patient group for evaluation of effect of SARS-CoV-2 vaccination on retinal hemorrhage are necessary.

Mean platelet component in nonproliferative and proliferative diabetic retinopathy

Introduction: Diabetic retinopathy (DR) remains a visually debilitating disease and is commonly classified according to its severity as non-proliferative DR (NPDR) or proliferative DR (PDR). Those suffering from PDR tend to have worse vascular complications and prognosis. Platelets exposed by vasculopathy caused by DR maybe activated to try to maintain haemostasis. This activity can be illustrated by the mean platelet component (MPC). Therefore, by MPC monitoring we may be able to predict the progression from NPDR into PDR.Purpose: To investigate the difference of MPC in patients with NPDR and PDR.Study design: Cross-sectional.Materials and methods: This study involved 71 DR patients. Preliminary data regarding the patients’ demographic characteristics, diabetes history, related diseases, medication history, and general eye examination were recorded. Fundus photographs were taken after dilating eyedrops and DR was graded by an ophthalmologist. The patients were grouped into NPDR and PDR. Mean platelet component was analyzed using the automatic hematology analyzer ADVIA 120.Results: Mean platelet component (MPC) was 26.69 g/dl (± 1.79) and 25.52 g/dl (± 1.20) in the NPDR and PDR group, respectively (p = 0.002), but was not clinically significant. In depth analysis into the DR grades differed significantly between mild NPDR and high-risk PDR (p = 0.015), and moderate NPDR and high-risk PDR (p = 0.024). Using our definition of mild DR (mild and moderate NPDR) and severe DR (high-risk and advanced PDR), there was a significant difference with mean MPC of 27.01 g/dl (± 1.64) and 25.31 g/dl (± 1.22), respectively (p = 0.001). The proportion of activated platelets was also higher in severe DR. Negative correlations were found between MPC with duration of DM (r = -0.333; p = 0.004) and MPC with systolic blood pressure (r = -0.241; p = 0.043).Conclusion: There was a significant difference in MPC between NPDR and PDR, but the results should be interpreted carefully. Further analysis between the mild and severe form of DR strengthened this finding.

Inter-eye comparison of retinal vascular growth rate and angiographic findings following unilateral bevacizumab treatment

Purpose To compare retinal vascularization progression rate, final retinal vascularization, and fluorescein angiography (FA) findings in infants who received intravitreal bevacizumab (IVB) treatment in one eye and with spontaneous regression in the other eye. Methods Thirty eyes of 15 infants who underwent IVB in one eye due to asymmetric retinopathy of prematurity, and who had pre-treatment fundus photographs and fluorescein angiography images were included in the study. Horizontal disc diameter (DD), optic disc-to-fovea distance (FD), and the length of temporal retinal vascularization (LTRV) distance were measured by evaluating pre-treatment and FA images. Results The mean ages at the time of treatment and FA were 40.38 ± 3.35 and 68.72 ± 10.52 weeks postmenstrual age, respectively. The pre-treatment LTRV/FD ratio was 3.11 ± 0.41 in the treated eyes and 3.26 ± 0.43 in the non-treated eyes (p = 0.053). The final LTRV/FD ratio was 4.23 ± 0.38 in the treated group and 4.33 ± 0.37 in the non-treated group (p = 0.286). Staining of the vessels, hyperfluorescent focus, and irregular branching of the vessels were similar between the groups, respectively (p = 1.000; p = 0.250; p = 0.625). Conclusion The progression rate of retinal vascularization and angiographic findings were similar between the treated eyes and the non-treated eyes. Our study suggests that incomplete retinal vascularization in eyes treated with anti-vascular endothelial growth factor (VEGF) is due to the nature of the disease, and anti-VEGF treatment was not to cause cessation in vascular progression.