Prevalence of Lens Opacities in Asian Malays

Deep Learning Automated Diagnosis and Quantitative Classification of Cataract Type and Severity

PURPOSE

To develop and evaluate deep learning models to perform automated diagnosis and quantitative classification of age-related cataract, including all three anatomical types, from anterior segment photographs.

DESIGN

Application of deep learning models to Age-Related Eye Disease Study (AREDS) dataset.

PARTICIPANTS

18,999 photographs (6,333 triplets) from longitudinal follow-up of 1,137 eyes (576 AREDS participants).

METHODS

Deep learning models were trained to detect and quantify nuclear cataract (NS; scale 0.9-7.1) from 45-degree slit-lamp photographs and cortical (CLO; scale 0-100%) and posterior subcapsular (PSC; scale 0-100%) cataract from retroillumination photographs. Model performance was compared with that of 14 ophthalmologists and 24 medical students. The ground truth labels were from reading center grading.

MAIN OUTCOME MEASURES

Mean squared error (MSE).

RESULTS

On the full test set, mean MSE values for the deep learning models were: 0.23 (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 the models was 0.23 (SD 0.02), compared to 0.98 (SD 0.23; p=0.000001) for the ophthalmologists, and 1.24 (SD 0.33; p=0.000005) for the medical students. For CLO, mean MSE values were 53.5 (SD 14.8), compared to 134.9 (SD 89.9; p=0.003) and 422.0 (SD 944.4; p=0.0007), respectively. For PSC, mean MSE values were 171.9 (SD 38.9), compared to 176.8 (SD 98.0; p=0.67) and 395.2 (SD 632.5; p=0.18), respectively. In external validation on the Singapore Malay Eye Study (sampled to reflect the distribution of cataract severity in AREDS), MSE was 1.27 for NS and 25.5 for PSC.

CONCLUSIONS

A deep learning framework was able to perform automated and quantitative classification of cataract severity for all three types of age-related cataract. For the two most common types (NS and CLO), the accuracy was significantly superior to that of ophthalmologists; for the least common type (PSC), the accuracy was similar. The framework 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 publicly available at https://XXX.

Clinical Aspects of Pterygium in the Presence of Cataract

Two of the most common UV-induced eye affections are pterygium and cataract. They are both defined as progressive diseases that impair patients’ vision and share some common elements in their evolution process. The purpose of this study was to determine whether the presence of cataract influences the clinical signs and symptoms of patients with pterygium. Therefore, we have analyzed 84 patients with pterygium, among which 23 also presented cataract, as an overall study lot, as well as divided by age decades. We have determined that almost all patients with both pterygium and cataract declared extensive UV exposure in antecedents and have also reported a blurred vision. We found no correlation between the presence of cataract and the size of pterygium lesions, or symptoms like foreign body sensation, tearing or symblepharon.

Systemic medications and cortical cataract: the Singapore Epidemiology of Eye Diseases Study

BACKGROUND/AIMS

To evaluate the association between systemic medications and cortical cataract prevalence in an Asian population.

METHODS

The Singapore Epidemiology of Eye Diseases Study recruited 10 033 Chinese, Malay and Indian residents aged 40+ years living in Singapore. Information on medication use was collected at interview using questionnaires. The presence and severity of cortical cataract were assessed from lens photographs using the modified Wisconsin Cataract Grading System. Associations between medications and the presence of cortical cataract were assessed using logistic regression. Associations between medications and greater severity of cortical cataract (none, minimal, early and late) were assessed using ordinal logistic regression.

RESULTS

A total of 8965 participants were included, the mean age was 57.6 (SD=9.8) years, and 4555 (50.8%) were women. After adjusting for age, gender, ethnicity, body mass index, smoking status, socioeconomic status, hypertension, hyperlipidaemia, diabetes, duration of diabetes and cardiovascular disease, ACE inhibitors (OR=1.27; 95% CI 1.05 to 1.55), fibrates (OR=1.57; 95% CI 1.05 to 2.35), alpha-glucosidase inhibitors (AGIs) (OR=1.85; 95% CI 1.13 to 3.02) and insulin (OR=1.80; 95% CI 1.11 to 2.93) were significantly associated with the presence of cortical cataract. Further adjusting for concurrent medication use did not alter these associations. Consistently, the four medications were also associated with a greater severity level of cortical cataract.

CONCLUSION

ACE inhibitors, fibrates and AGIs were associated with increased prevalence of cortical cataract in this Asian population, independent of the presence of hypertension, hyperlipidaemia and diabetes, respectively. Whether they contribute to the risk of cortical cataract needs confirmation in longitudinal studies.

Association between ultraviolet radiation exposure dose and cataract in Han people living in China and Taiwan: A cross-sectional study

Purpose

We investigated associations between ocular ultraviolet (UV) radiation exposure dose and cataract opacities among Han people living in China and Taiwan, to assess the effects of UV exposure intensity.

Methods

This cross-sectional study included Han people aged ≥40 years (1,801 individuals, 450 in Sanya, 636 in Taiyuan, and 715 in Taichung) as subjects who completed a questionnaire including items about diabetes, smoking, steroid use, work history, and time spent outdoors, and underwent an ophthalmic examination. Right eye axial length was measured using A-mode ultrasonography or IOLMaster. Slit-lamp imaging under maximum mydriasis was used to classify cataracts into three major types [cortical (COR), nuclear (NUC), and posterior subcapsular cataracts (PSC)] and two subtypes [retrodots (RD) and waterclefts (WC)] by one ophthalmologist. COR was divided into opacity presence (CEN+) or absence (CEN-) in the central 3-mm diameter area of the pupil. COR was also subdivided into three groups according to opacity shape: axle-shaped opacity concomitant with WC, wedge-shaped opacity around the pupil to the eye center, and ring-shaped opacity in the lens equator along the pupillary margin. The cumulative ocular UV exposure (COUV) was calculated. A logistic regression analysis was used for multivariate analysis.

Results

Cataract odds ratios in high COUV eyes were 5.35 for NUC, 1.87 for PSC, and 1.35 for RD. In eyes with WC, risk of COR ring-shaped opacity significantly increased but that of wedge-shaped opacity (CEN+) significantly decreased. In eyes without WC, risk of COR axle-shaped opacity (CEN–) and ring-shaped opacity significantly increased but that of wedge-shaped opacity (CEN+) significantly decreased.

Conclusions

Increased COUV level among Han people may be a risk factor for the development of nuclear cataracts, PSC, retrodots and ring-shaped cortical cataract. Risk of ocular UV exposure for cortical cataract may differ by opacity shape.

The Effect of Gender on Visual Field Sensitivity: The Singapore Chinese Eye Study

PURPOSE

Visual field (VF) sensitivity is known to be age-dependent, but there is a paucity of evidence on whether it is gender-dependent. We therefore investigated the effect of gender on VF sensitivity.

METHODS

An observational study involving 491 adults from the population-based Singapore Chinese Eye Study (SCES). Study participants underwent a comprehensive and standardised ocular examination and VF assessment on the Humphrey Field Analyzer II (Carl Zeiss Meditec, Inc., Dublin, CA, USA). The effect of gender on the mean deviation (MD) and pattern standard deviation (PSD) was analysed with linear regression models.

RESULTS

The mean age was 52.9 ± 5.9 years, and 229 (46.6%) participants were women. A total of 800 reliable VFs from 655 healthy eyes without visual impairment, glaucoma and significant cataract were included. The mean (± standard deviation) MD was -0.45 ± 1.01 dB in men, and -0.84 ± 1.20 dB in women. The MD [95% confidence interval] was 0.28 [-0.44 to -0.12] dB lower in females compared to males (P = 0.001) after adjusting for reliability indices, degree of lens opacity, and other potential confounders. The PSD was not significantly different between the genders.

CONCLUSIONS

In the SCES, the population-average of the central VF sensitivity was significantly lower in women compared to men by a small amount (0.28 dB). This effect was observed in healthy eyes, and was not explained by multiple potential confounders. Hence, this likely represents a physiological gender-based difference that is unaccounted for in standard automated perimetry. Further studies in other populations would be needed to corroborate our findings.

Prevalence, Risk Factors, and Impact of Undiagnosed Visually Significant Cataract: The Singapore Epidemiology of Eye Diseases Study

Objective

To determine the prevalence, risk factors, and impact of undiagnosed visually significant cataract in an Asian population.

Methods

The Singapore Epidemiology of Eye Diseases is a population-based study where 8,697 adults of Malay, Indian, and Chinese ethnicities aged > 40 years were invited for an eye examination, including lens photograph, to establish cataract diagnosis. Visually significant cataract was defined by Wisconsin Cataract Grading System and a best-corrected visual acuity <20/40 with cataract as the primary cause of vision impairment. Participants were deemed ‘undiagnosed’ if they had visually significant cataract and reported no prior physician diagnosis of cataract. Visual functioning (VF) was assessed with the VF-11 questionnaire validated using Rasch analysis.

Results

Among the 925 participants with visually significant cataract, 636 (68.8%) were unaware of their cataract status. Age-standardized prevalence varied according to ethnicity, with Malays having higher rates than Chinese and Indians. Factors independently associated with having undiagnosed visually significant cataract were: Malay ethnicity, lower educational attainment, in employment, and without a history of diabetes (all P<0.05). In those with undiagnosed visually significant cataract, half had bilateral visual impairment, which was significantly associated with 24.8% poorer visual functioning compared to those with unilateral visual impairment (P<0.001).

Conclusions

Two-thirds of Singaporean adults with visually significant cataract were previously undiagnosed. Half of these cases had bilateral visual impairment and substantially reduced quality of life. Public health strategies targeting elderly patients, such as regular screening for visual impairment and timely referral to ophthalmologists in order to prevent progression to bilateral visual impairment when visual function is compromised are warranted.

An Ophthalmic Formulation of Disulfiram Nanoparticles Prolongs Drug Residence Time in Lens

Disulfiram (DSF) is a dimer of diethyldithiocarbamate (DDC) that we previously added to a solution of 2-hydroxypropyl-β-cyclodextrin (DSF solution). We found that the instillation of this DSF solution delayed lens opacification in a hereditary cataractous ICR/f rat. In this study, we attempted to design an ophthalmic formulation containing DSF nanoparticles for use as a lens targeted drug delivery system (nano-DSF suspension), and investigated the changes in drug content in the lens after the instillation of DSF solution or nano-DSF suspension. The nano-DSF suspension was prepared by a bead mill method to yield a mean particle size of nano-DSF of 181 nm. Following the instillation of 1.4% DSF solution or the nano-DSF suspension, DDC was detected only in the aqueous humor and lens; in both, the area under the curve (AUC) and mean residence time (MRT) for the nano-DSF suspension were higher than for the DSF solution. In addition, we found that the DDC residence time in the cortex and nucleus of the lens was higher than in the capsule-epithelium. Although DDC was not detected in the cortex and nucleus of lenses following the instillation of the 1.4% DSF solution, the instillation of a 1.4% nano-DSF suspension led to the accumulation of DDC in both areas. In conclusion, it is possible that the instillation of a nano-DSF suspension can supply more DDC into the aqueous humor and lens than a conventional formulation, and these findings provide information significant for the prevention of cataracts and the design of a lens targeted drug delivery system.

The location of incision in cataract surgery and its impact on induced astigmatism

PURPOSE OF REVIEW

The purpose of the present study is a systematic review of previous studies on choosing the best incision site for the correction of astigmatism in cataract surgery and assessing the amount of surgically induced astigmatism (SIA) with each approach.

RECENT FINDINGS

Regardless of astigmatism axis, studies show that using an on-axis incision is associated with favorable results for 0.5-1.0 diopter (D) of astigmatism. In cases with more than 1.0 D astigmatism, paired on-axis incisions can be appreciably efficient in astigmatism correction and cause at least 1.5 D SIA. Considering the amount of SIA, a temporal incision is the best approach when the patient has minimal amounts of corneal astigmatism preoperatively. At higher levels of astigmatism, if no other astigmatism correction method is used simultaneously, the temporal incision is used less frequently; however, since it is associated with the least SIA, it is still the choice site when another correction method is used.

SUMMARY

The temporal incisions in cataract surgery are associated with little SIA and are appropriate choices for mild preoperative astigmatism. At higher levels of preoperative astigmatism, superior incisions are associated with better results when combined methods are not applied.

Ancestry, Socioeconomic Status, and Age-Related Cataract in Asians: The Singapore Epidemiology of Eye Diseases Study

PURPOSE

To determine the prevalence of age-related cataract and its ancestral and socioeconomic risk factors in a multi-ethnic Asian population.

DESIGN

Population-based, cross-sectional study.

PARTICIPANTS

A total of 10 033 adults (3353 Chinese, 3280 Malays, and 3400 Indians) aged >40 years in the Singapore Epidemiology of Eye Diseases Study.

METHODS

Study participants were invited for a structured interview and received a standardized comprehensive eye examination. Digital lens photographs were taken from eyes of each participant and graded for nuclear, cortical, and posterior subcapsular (PSC) cataract, following the Wisconsin Cataract Grading System. Prevalence data were compared with the Blue Mountains Eye Study (BMES) in Australia. Information on medical and lifestyle factors was collected using questionnaires and blood samples. To increase the precision of racial definition, genetic ancestry was derived from genome-wide single nucleotide polymorphism markers using principal component analysis. Regression models were used to investigate the association of cataract with socioeconomic factors (education and income) and genetic ancestry.

MAIN OUTCOME MEASURES

Age-related cataract.

RESULTS

A total of 8750 participants (94.0%) had gradable lens photographs. The age-standardized prevalence of cataract surgery in Chinese (16.0%), Malays (10.6%), and Indians (20.2%) was higher than in white subjects (4.1%). We found the age-standardized cataract prevalence in Chinese (30.4%), Malays (37.8%), and Indians (33.1%) was higher than in whites (18.5%). Cataract was 1.5 to 2 times more common in Asians and began 10 years earlier than in white subjects. Malays had significantly higher age-standardized prevalence of nuclear, cortical, and PSC cataract than Chinese (P<0.001). The severity of nuclear, cortical, and PSC cataract was significantly correlated with genetic ancestry in our South East Asian population. Less education and lower income were associated with cataract for Chinese and Indians but not Malays. The presence of visual impairment associated with cataract was higher in people aged ≥60 years and Malays.

CONCLUSIONS

We showed that people of different Asian ethnicities had a higher prevalence and earlier age of onset of cataract than Europeans. People of Malay ancestry have a greater severity for all cataract subtypes than people of Chinese ancestry. Education and income were associated with cataract for certain Asian subgroups.