DeepLensNet: Deep Learning Automated Diagnosis and Quantitative Classification of Cataract Type and Severity.

PURPOSE: To develop deep learning models to perform automated diagnosis and quantitative classification of age-related cataract from anterior segment photographs. DESIGN: DeepLensNet was trained by applying deep learning models to the Age-Related Eye Disease Study (AREDS) dataset. PARTICIPANTS: A total of 18 999 photographs (6333 triplets) from longitudinal follow-up of 1137 eyes (576 AREDS participants). METHODS: Deep learning models were trained to detect and quantify nuclear sclerosis (NS; scale 0.9-7.1) from 45-degree slit-lamp photographs and cortical lens opacity (CLO; scale 0%-100%) and posterior subcapsular cataract (PSC; scale 0%-100%) from retroillumination photographs. DeepLensNet performance was compared with that of 14 ophthalmologists and 24 medical students. MAIN OUTCOME MEASURES: Mean squared error (MSE). RESULTS: On the full test set, mean MSE for DeepLensNet was 0.23 (standard deviation [SD], 0.01) for NS, 13.1 (SD, 1.6) for CLO, and 16.6 (SD, 2.4) for PSC. On a subset of the test set (substantially enriched for positive cases of CLO and PSC), for NS, mean MSE for DeepLensNet was 0.23 (SD, 0.02), compared with 0.98 (SD, 0.24; P = 0.000001) for the ophthalmologists and 1.24 (SD, 0.34; P = 0.000005) for the medical students. For CLO, mean MSE was 53.5 (SD, 14.8), compared with 134.9 (SD, 89.9; P = 0.003) for the ophthalmologists and 433.6 (SD, 962.1; P = 0.0007) for the medical students. For PSC, mean MSE was 171.9 (SD, 38.9), compared with 176.8 (SD, 98.0; P = 0.67) for the ophthalmologists and 398.2 (SD, 645.4; P = 0.18) for the medical students. In external validation on the Singapore Malay Eye Study (sampled to reflect the cataract severity distribution in AREDS), the MSE for DeepSeeNet was 1.27 for NS and 25.5 for PSC. CONCLUSIONS: DeepLensNet performed automated and quantitative classification of cataract severity for all 3 types of age-related cataract. For the 2 most common types (NS and CLO), the accuracy was significantly superior to that of ophthalmologists; for the least common type (PSC), it was similar. DeepLensNet may have wide potential applications in both clinical and research domains. In the future, such approaches may increase the accessibility of cataract assessment globally. The code and models are available at https://github.com/ncbi/deeplensnet.

Postoperative complicated peripheral cortical cataract after ultrasound cycloplasty: a case report.

BACKGROUND: Ultrasound cycloplasty (UCP) is a non-invasive procedure for glaucoma treatment. Using high-intensity focused ultrasound to work on the ciliary body, the generation of aqueous humor can be reduced and the drainage of aqueous humor through the uveoscleral pathway can be enhanced. Recently, this therapy is gradually gaining clinical recognition. We report a case of a patient with glaucoma who accepted UCP in another hospital, but because of a worsening of a preexistent cataract and an insufficient IOP lowering effect, finally underwent cataract surgery in both eyes in our hospital, during the surgery we observed the unusual opacities probably due to UCP mistreatment. CASE PRESENTATION: Patient was diagnosed as chronic angle closure glaucoma and catacract, accepted UCP on both eyes in another hospital 4 months ago. After the UCP therapy, the pupil was vertical ellipse, the UCP didn't have a sufficient effect on IOP and forced us to do cataract surgery to lower IOP. During the cataract surgery, some unusual white opacities in the peripheral cortex with clear boundary were found. Inaccurate WtW measurement was the most likely cause of the injury, which resulted in the use of the small-size UCP probe and the downward movement of the UCP probe. CONCLUSION: UCP should not be a first line treatment in a patient with cataract and angle closure glaucoma, cataract extraction is a better choice. The appropriate case selection needs to be more strict and the preoperative indexes measurements need to be more accurate.

Novel Homozygous Missense Variant in GJA3 Connexin Domain Causing Congenital Nuclear and Cortical Cataracts.

Congenital cataracts (CC) are responsible for approximately one-tenth of childhood blindness cases globally. Here, we report an African American family with a recessively inherited form of CC. The proband demonstrated decreased visual acuity and bilateral cataracts, with nuclear and cortical cataracts in the right and left eye, respectively. Exome sequencing revealed a novel homozygous variant (c.563A > G; p.(Asn188Ser)) in GJA3, which was predicted to be pathogenic by structural analysis. Dominantly inherited variants in GJA3 are known to cause numerous types of cataracts in various populations. Our study represents the second case of recessive GJA3 allele, and the first report in African Americans. These results validate GJA3 as a bona fide gene for recessively inherited CC in humans.

Spontaneous resolution of a traumatic cataract in a patient with an open-globe ocular injury: a case report.

BACKGROUND: We report a case of spontaneous resolution of a traumatic cataract in a patient with an open-globe ocular injury. This case highlights the importance of conservative management in these types of cases, as excellent visual outcome is possible without invasive surgical intervention. CASE PRESENTATION: A 13-year-old boy presented with a corneal laceration in the left eye caused by a neuter pen. He underwent emergency repair of the corneal laceration under general anesthesia, and at 3 days post-op, a dense posterior cortical cataract was observed. Based on the patient's age and normal visual development, in addition to preserving accommodative potential, the patient received conservative management and follow-up. Interestingly, the cataract spontaneously resolved over the following 9 months and the corrected distance visual acuity in the injured eye was restored from finger counting at 50 cm, to 20/25 + 3. CONCLUSIONS: To optimize treatment in pediatric traumatic cataract, several critical factors such as age, visual development and the preservation of accommodative potential, need to be comprehensively considered. Conservative management with lens preservation is important to consider in young, traumatic cataract patients where invasive surgical intervention may not be required.

Cortical Cataract and Refractive Error.

PURPOSE: To evaluate the relationship between the presence of cortical cataract and accommodation effort, using refractive error as a proxy. METHODS: Patients between 50 and 90 years, scheduled for cataract surgery, were selected with the help of a photographic database. Nuclear and cortical cataract were graded and patients grouped having no cataract, pure cortical, mixed or pure nuclear cataract. Refraction data at the time of the photograph was converted to estimated spherical equivalent refractive error each patient would have had at the age of 45 years. RESULTS: From the initial 239 eyes from 239 patients, cases with myopia below -6.5 dpt and hyperopia above 6.5 dpt were excluded, resulting in 199 cases for final analysis. Eyes with no cataract showed the lowest median refractive error (-3.65 dpt), followed by the pure nuclear group (-2.69 dpt). The median refractive error for pure cortical (-0.23 dpt) and mixed cataracts (-0.87 dpt) were close to emmetropia. Cortical cataracts were found in 37% of myopes, 82% of emmetropes, and 85% of hyperopes. CONCLUSION: Emmetropes and hyperopes tend to develop more cortical cataract than myopes. These cortical cataracts might be caused by shear stress inside the crystalline lens due to accommodation efforts at the time of onset of presbyopia.

Risk of various types of cataracts in a cohort of Mayak workers following chronic occupational exposure to ionizing radiation.

This study is the first to report cataract type specific risks in a cohort of Russian Mayak Production Association workers following chronic occupational exposure to ionizing radiation. In this retrospective cohort study, 22,377 workers (females 25.4%) first employed in 1948-1982 were followed up till the end of 2008. All cataract subtypes were significantly dependent on sex, attained age, diabetes mellitus, myopia and glaucoma. For each of posterior subcapsular (PSC), cortical and nuclear cataracts, the risk of cataract incidence significantly linearly increased with increasing radiation dose. Excess relative risk per unit effective dose (ERR/Sv) from external γ-rays based on the linear model was 0.91 [95% confidence intervals (CIs) 0.67, 1.20] for PSC, 0.63 (95% CIs 0.49, 0.76) for cortical, and 0.47 (95% CIs 0.35, 0.60) for nuclear cataracts. For all three types of cataracts, exclusion of an adjustment for neutron dose as well as inclusion of additional adjustments for body mass index and smoking index decreased ERR/Sv of external γ-rays. Inclusion of an additional adjustment for glaucoma, however, modestly increased incidence risks for cortical and nuclear cataracts, but not PSC cataracts. Inclusion of an adjustment for diabetes mellitus decreased ERR/Sv of external γ-rays only for PSC incidence. Both males and females had increased risks for all three types of cataracts, but ERR/Sv was significantly higher in females than in males (p < 0.001), particularly for PSC cataracts. The results suggest that chronic occupational radiation exposure significantly increases risks of PSC, cortical and nuclear cataracts, and that such risks are higher in females than in males.

Protein profiles in cortical and nuclear regions of aged human donor lenses: A confocal Raman microspectroscopic and imaging study.

A combination of Raman spectroscopy, imaging, hierarchical cluster analysis (HCA) and peak ratio analysis was used to analyze protein profiles in the superficial cortex (SC), deep cortex (DC) and nucleus of old human lenses with cortical, nuclear and mixed cataracts. No consistent differences were observed in protein spectra and after cluster analysis between the three locations irrespective of the presence or absence of cortical opacities and/or coloration. A sharp increase (∼15%-∼33%) in protein content from SC to DC, normal for human lenses, was found in 7 lenses. In 4 lenses, characterized by the absence of cortical opacities, the SC has a protein content of ∼35%. A significant increase in the disulfide-to-protein ratio is found only in the SC of the 7 cortical cataracts. No changes were found in sulfhydryl-to-protein ratio. The relative contents of α-helices and ß-sheets increase from SC to nucleus. ß-Sheets are more common in the SC of lenses with cortical cataract. The absence of significant and consistent changes in protein profiles between nucleus and cortex even in cases of severe coloration is not favoring the prevailing concept that ubiquitous protein oxidation is a key factor for age related nuclear (ARN) cataracts. The observations favor the idea that multilamellar bodies or protein aggregates at very low volume densities are responsible for the rise in Mie light scatter as a main cause of ARN cataracts leaving the short-range-order of the fiber cytoplasm largely intact. The absence of significant changes in the protein spectra of the deep cortical opacities, milky white as a result of the presence of vesicle-like features, indicate they are packed with relatively undisturbed crystallins.

Regional changes of AQP0-dependent square array junction and gap junction associated with cortical cataract formation in the Emory mutant mouse.

The Emory mutant mouse has been widely used as an animal model for human senile cataract since it develops late-onset hereditary cataract. Here, we focus on the regional changes of aquaporin-0 (AQP0) and connexins that are associated with the cortical cataract formation in the Emory mutant mice. Emory mutant and CFW wild-type mice at age 1-16 months were used in this study. By using an established photography system with dissecting microscopy, the opacities were first detected at the anterior or posterior lens center surface in Emory mice at age 7 months, and gradually extended toward the equator during the 16 months examined. Scanning EM verified that disorganized and fragmented fiber cells were associated with the areas of opacities within approximately 200 µm from the lens surface, indicating that Emory mouse cataracts belong to the cortical cataracts. Freeze-fracture TEM further confirmed that cortical cataracts exhibited extensive wavy square array junctions, small gap junctions and globules. Immunofluorescence analysis showed that in contrast to the high labeling intensity of AQP0-loop antibody, the labeling of AQP0 C-terminus antibody was decreased considerably in superficial fibers in Emory cataracts. Similarly, a significant decrease in the labeling of the antibody against Cx50 C-terminus, but not Cx46 C-terminus, occurred in superficial and outer cortical fibers in Emory cataracts. Western blotting further revealed that the C-termini of both AQP0 and Cx50 in Emory cataracts were decreased to over 50% to that of the wild-type. Thus, this systematic study concludes that the Emory mouse cataract belongs to the cortical cataract which is due to regional breakdown of superficial fibers associated with formation of AQP0-dependent wavy square array junctions, small gap junctions and globules. The marked decreases of the C-termini of both AQP0 and Cx50 in the superficial fibers may disturb the needed interaction between these two proteins during fiber cell differentiation and thus play a role in the cortical cataract formation in Emory mutant mice.

Multi-style spatial attention module for cortical cataract classification in AS-OCT image with supervised contrastive learning.

BACKGROUND AND OBJECTIVE: Precise cortical cataract (CC) classification plays a significant role in early cataract intervention and surgery. Anterior segment optical coherence tomography (AS-OCT) images have shown excellent potential in cataract diagnosis. However, due to the complex opacity distributions of CC, automatic AS-OCT-based CC classification has been rarely studied. In this paper, we aim to explore the opacity distribution characteristics of CC as clinical priori to enhance the representational capability of deep convolutional neural networks (CNNs) in CC classification tasks. METHODS: We propose a novel architectural unit, Multi-style Spatial Attention module (MSSA), which recalibrates intermediate feature maps by exploiting diverse clinical contexts. MSSA first extracts the clinical style context features with Group-wise Style Pooling (GSP), then refines the clinical style context features with Local Transform (LT), and finally executes group-wise feature map recalibration via Style Feature Recalibration (SFR). MSSA can be easily integrated into modern CNNs with negligible overhead. RESULTS: The extensive experiments on a CASIA2 AS-OCT dataset and two public ophthalmic datasets demonstrate the superiority of MSSA over state-of-the-art attention methods. The visualization analysis and ablation study are conducted to improve the explainability of MSSA in the decision-making process. CONCLUSIONS: Our proposed MSSANet utilized the opacity distribution characteristics of CC to enhance the representational power and explainability of deep convolutional neural network (CNN) and improve the CC classification performance. Our proposed method has the potential in the early clinical CC diagnosis.

Application of artificial intelligence for automatic cataract staging based on anterior segment images: comparing automatic segmentation approaches to manual segmentation.

Purpose: Cataract is one of the leading causes of blindness worldwide, accounting for >50% of cases of blindness in low- and middle-income countries. In this study, two artificial intelligence (AI) diagnosis platforms are proposed for cortical cataract staging to achieve a precise diagnosis. Methods: A total of 647 high quality anterior segment images, which included the four stages of cataracts, were collected into the dataset. They were divided randomly into a training set and a test set using a stratified random-allocation technique at a ratio of 8:2. Then, after automatic or manual segmentation of the lens area of the cataract, the deep transform-learning (DTL) features extraction, PCA dimensionality reduction, multi-features fusion, fusion features selection, and classification models establishment, the automatic and manual segmentation DTL platforms were developed. Finally, the accuracy, confusion matrix, and area under the receiver operating characteristic (ROC) curve (AUC) were used to evaluate the performance of the two platforms. Results: In the automatic segmentation DTL platform, the accuracy of the model in the training and test sets was 94.59 and 84.50%, respectively. In the manual segmentation DTL platform, the accuracy of the model in the training and test sets was 97.48 and 90.00%, respectively. In the test set, the micro and macro average AUCs of the two platforms reached >95% and the AUC for each classification was >90%. The results of a confusion matrix showed that all stages, except for mature, had a high recognition rate. Conclusion: Two AI diagnosis platforms were proposed for cortical cataract staging. The resulting automatic segmentation platform can stage cataracts more quickly, whereas the resulting manual segmentation platform can stage cataracts more accurately.

[Alterations of the anterior segment of the eye caused by exposure to UV radiation]. / UV-strahlenexpositionsbedingte Veränderungen am vorderen Augenabschnitt.

BACKGROUND: By identifying diseases of the anterior segment of the eye associated with exposure to UV light, recommendations for action can be derived. AIM: After reading this review, the reader should be familiar with UV light-associated diseases of the anterior segment of the eye. METHOD: Using a selective literature search, UV light-associated diseases of the anterior segment of the eye were identified and protective mechanisms are described. RESULTS: The UV light-associated lesions of the anterior segment of the eye include basal cell and squamous cell carcinomas, malignant melanoma of the eyelids and conjunctiva, pterygium, keratoconjunctivitis photoelectrica and climatic droplet keratopathy as well as cortical cataract. CONCLUSION: Eyeglasses for filtering UV light, sunglasses and special safety glasses, such as welding helmets and wearing headgear protect against UV light exposure to the anterior segment of the eye and the associated diseases.

Age- and Sex-Standardized Prevalence of Age-Related Cataract and Its Determinants; Tehran Geriatric Eye Study (TGES).

PURPOSE: To determine the prevalence of cataract and its relationship with some determinants in individuals above 60 years. METHODS: Of 3792 subjects that were invited, 3310 participated in the study (response rate = 87.31%). All subjects underwent full optometric, slit lamp, and fundoscopic examinations. Then, their lenses were evaluated according to the World Health Organization cataract grading system after pupil dilation. RESULTS: Age- and sex-standardized prevalence with 95% confidence interval (CI) of nuclear, cortical, posterior subcapsular cataracts (PSC), any type cataract, and all lens change was 53.09% (49.80 to 56.35), 23.02% (20.87 to 25.32), 5.57% (4.62 to 6.70), 58.78% (55.65 to 61.83), and 72.49% (70.14 to 74.71), respectively. Any type, nuclear, cortical, and PSC cataracts, had a positive association with age and an inverse association with education. Moreover, the prevalence of cortical and PSC cataract had an inverse association with economic status. Among all variables, age was the strongest determinant for cataract and its subtype. CONCLUSION: This study found a higher prevalence of cataract compared to some previous studies such that about two-thirds of the geriatric population had cataract in the past or at the time of the study. Considering the association of cataract with variables such as economic status and education level, it seems that training and increased awareness and knowledge of the elderly population regarding the importance of eye care by physicians plays an important role in reducing the burden of cataract.

Cataract frequency and subtypes involved in workers assessed for their solar radiation exposure: a systematic review.

Cataract is currently the primary cause of blindness worldwide, and one of its main risk factors is solar ultraviolet radiation exposure. According to the localization of lens opacities, three main subtypes of cataract are recognized: nuclear, cortical and posterior subcapsular cataract. One of the main determinants of individual long-term solar radiation exposure is outdoor work. We systematically reviewed scientific literature from the last 20 years to update the recent development of research on the risk of cataract in outdoor workers and on the specific subtypes involved, also investigating the methods applied to evaluate the occupational risk. A total of 15 studies were included in the review, of which 12 showed a positive association. The studies confirm the relationship of long-term occupational solar radiation exposure with cortical cataract and give new support for nuclear cataract, although no substantial new data were available to support a relation with the posterior subcapsular subtype. In most of the studies, the exposure assessment was not adequate to support a representative evaluation of the ocular risk; however, outdoor work is clearly a relevant risk factor for cataract. Further research providing a better evaluation of the relation between solar radiation exposure levels and lens damage in workers is needed and aimed to establish adequate occupational exposure limits and better preventive measures, studying also their effectiveness.

Evaluation of antioxidants and argpyrimidine in normal and cataractous lenses in north Indian population.

AIM: To assess the level of glutathione, thioltransferase, and argpyrimidine in nuclear and cortical cataractous lenses as well as in the clear lenses in the north Indian population. METHODS: Human cataractous lenses were collected from the patients who underwent extracapsular cataract extraction surgery; clear lenses were collected from the freshly donated eye bank eyes. Antioxidant molecules such as glutathione and thioltransferase enzyme activity were measured; simultaneously in these lenses a blue fluorophore argpyrimidine, an advanced glycation end (AGE) product level was assessed using high performance liquid chromatography (HPLC). RESULTS: The protein concentration was found to be present at higher levels in the control lenses compared to cataract lenses. A significant decrease in the glutathione level was observed in the nuclear cataractous lenses compared to cortical cataractous (P=0.004) and clear lenses (P≤0.005), but no significant change in the level of antioxidant enzyme thioltransferase was observed. Further, argpyrimidine a blue fluorophore (AGE) was found to be significantly higher in the nuclear cataract (P=0.013) compared to cortical cataract lenses. CONCLUSION: Antioxidants such as glutathione significantly decrease in age-related nuclear and cortical cataract and an AGE, argpyrimidine are present at significantly higher levels in nuclear cataract.

Subfoveal choroidal thickness and cataract: the Beijing Eye Study 2011.

PURPOSE: This study examined subfoveal choroidal thickness (SFCT) in eyes with cataracts. METHODS: The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6 ± 9.8 years (range, 50-93 years of age). Enhanced depth imaging spectral domain optical coherence tomography was applied for measurement of SFCT. Using lens photographs, we graded cataracts by the Age-Related Eye Disease Study system. RESULTS: Assessments of SFCT and cataract were available for 2548 subjects. After adjusting for age, axial length, sex, anterior chamber depth, and lens thickness, we found that SFCT was not significantly associated with presence of nuclear cataract (P = 0.41). Conversely, the degree of nuclear cataract (P = 0.73) was not significantly associated with SFCT after adjusting for age and sex. In contrast, thicker SFCT was significantly associated with lower degree of posterior subcapsular cataract (P = 0.027; standardized regression coefficient ß: -0.04; regression coefficient B: -127; 95% confidence interval [CI]: -240 to -15) or with lower degree of cortical cataract (P = 0.028; ß:-0.06; B: -51.5; 95% CI: -97.3 to -5.59) after adjusting for younger age, shorter axial length, and deeper anterior chamber. Conversely, the degree of posterior subcapsular cataract (P = 0.027; ß:-0.06) or the degree of cortical cataract (P = 0.01; ß: -2.55) was associated with thinner SFCT in multivariate analysis. Correspondingly in binary regression analysis, presence of subcapsular cataract was associated with older age (P < 0.001; odds ratio (OR): 1.11; 95% CI: 1.09-1.14) and thinner SFCT (P = 0.006; OR: 0.997; 95% CI: 0.995-0.999). CONCLUSIONS: Although nuclear cataract was not significantly associated with an abnormal SFCT, the association between thin SFCT and subcapsular cataract or cortical cataract may have clinical importance, because thin SFCT is associated with low vision.

UV-B-induced DNA damage and repair in the mouse lens.

PURPOSE: Epidemiologic studies have linked UV-B exposure to development of cortical cataracts, but the underlying molecular mechanism(s) is unresolved. Here, we used a mouse model to examine the nature and distribution of DNA photolesions produced by ocular UV-B irradiation. METHODS: Anesthetized mice, eye globes, or isolated lenses were exposed to UV-B. Antibodies specific for 6-4 photoproducts (6-4 PPs) or cyclobutane pyrimidine dimers (CPDs) were used to visualize DNA adducts. RESULTS: Illumination of intact globes with UV-B-induced 6-4 PP and CPD formation in cells of the cornea, anterior iris, and central lens epithelium. Photolesions were not detected in retina or lens cells situated in the shadow of the iris. Photolesions in lens epithelial cells were produced with radiant exposures significantly below the minimal erythemal dose. Lens epithelial cells rapidly repaired 6-4 PPs, but CPD levels did not markedly diminish, even over extended postirradiation recovery periods in vitro or in vivo. The repair of 6-4 PPs did not depend on the proliferative activity of the epithelial cells, since the repair rate in the mitotically-active germinative zone (GZ) was indistinguishable from that of quiescent cells in the central epithelium. CONCLUSIONS: Even relatively modest exposures to UV-B produced 6-4 PP and CPD photolesions in lens epithelial cells. Cyclobutane pyrimidine dimer lesions were particularly prevalent and were repaired slowly if at all. Studies on sun-exposed skin have established a causal connection between photolesions and so-called UV-signature mutations. If similar mechanisms apply in the lens, it suggests that somatic mutations in lens epithelial cells may contribute to the development of cortical cataracts.

Association of G>A transition in exon-1 of alpha crystallin gene in age-related cataracts.

AIM: To identify the presence of a known or novel mutation/SNP in Exon-1 (ex-1) of alpha crystallin (CRYAA) gene in different types of age-related cataract (ARC) patients. MATERIALS AND METHODS: Single strand Conformation Polymorphism (SSCP) analysis was carried for the detection of single nucleotide polymorphism (SNP) in ex-1 of alpha crystallin (CRYAA) gene which was confirmed by sequencing. RESULTS: The SSCP analysis of ex-1 of CRYAA gene revealed mobility shift in patients and controls, which was due to G>A transition at 6(th) position in exon-1 of CRYAA gene. All the three genotypes, GG, AA and GA, were detected in patients and controls indicating that G>A substitution is polymorphic. The analysis showed significant risk for heterozygotes (GA) as compared to pooled frequencies of homozygotes (GG + AA), which was 1.81 times for all the types of cataracts in general and 2.5 times for Nuclear Cataract and twice for Cortical Cataract. CONCLUSION: The GA heterozygotes were at higher risk for developing NC and CC types of cataracts, where as the GG homozygotes for MT and AA homozygotes for PSC types were at risk. To our knowledge, an association of G>A transition found in ex-1 of CRYAA gene with ARC, with differential risk of genotypes for individual type of cataracts has not been reported previously.