Multivariable Analyses of Amblyopia Treatment Outcomes from a Clinical Data Registry

Visual Outcomes after Strabismus Surgery in Pediatric Patients with Strabismic Amblyopia: An IRIS® Registry Study

PURPOSE

To evaluate the impact of strabismus surgery on visual outcomes in pediatric patients with strabismic amblyopia.

DESIGN

Retrospective analysis of the American Academy of Ophthalmology IRIS® Registry (Intelligent Research in Sight).

PARTICIPANTS

Pediatric patients aged 3 to 17 with strabismus and amblyopia.

METHODS

Visual acuity (VA) was assessed at 6, 12, and 24 months post amblyopia diagnosis. Patients were categorized based on age (3-7, 8-12, 13-17 years) and whether they had strabismus surgery before or within 6 months of amblyopia diagnosis. Propensity score matching (PSM) was used to pair the patients who performed strabismus surgery with patients who did not.

MAIN OUTCOME MEASURES

VA changes and treatment efficacy, assessed using the modified IRIS-50 outcome measure.

RESULTS

Of the 21,242 patients analyzed, 1,703 underwent surgery within 6 months of amblyopia diagnosis and 19,539 did not. In PSM cohort, among patients with baseline VA worse than 20/30, visual acuity significantly improved over time in both the strabismus surgery and no strabismus surgery groups. Overall, VA improved from 0.46 ± 0.21 logMAR at baseline to 0.29 ± 0.24 logMAR at 24 months (P < 0.001), with significant improvements observed in both groups at each follow-up (6, 12, and 24 months). Improvement was most pronounced in the youngest group (ages 3-7 years), while teenage patients (ages 13-17 years) showed no improvement. There were no significant differences in visual outcomes between patients who had strabismus surgery and those who did not at any time point. In multivariable logistic regression, there was no difference in the odds of treatment success, as measured by IRIS-50, at the final follow-up between patients who underwent strabismus surgery and those who did not. This was true in all age categories.

CONCLUSIONS

Strabismus surgery did not significantly impact visual outcomes in patients with strabismic amblyopia. Older patients, up to at least age 12, may still have visual benefits from both strabismus surgery and amblyopia treatment.

Socioeconomic associations of amblyopia in the All of Us research program

PURPOSE

To identify potential socioeconomic associations of amblyopia in a nationwide cohort.

METHODS

This is a retrospective, case-control study of participants in the All of Us Research Program. Cases were defined as adults 18-64 years of age with a diagnosis of amblyopia who answered the "Basics" survey questions of interest. Age-, sex-, and race-matched controls with no amblyopia diagnosis were sampled at a 4:1 control-to-case ratio. Univariate and multivariable testing was performed to determine socioeconomic associations of amblyopia, with P values of <0.05 considered statistically significant.

RESULTS

Of 1,714 patients with a diagnosis of amblyopia, 859 fell within the defined age range. Amblyopic participants were more likely to be of Black or African American (25.8% vs 21.8% [P = 0.004]) or Hispanic race/ethnicity (25.6% vs 22.6% [P = 0.04]) and were significantly older (50.0 vs 46.6 years [P < 0.0001]) than unmatched controls. After applying additional inclusion criteria limiting analysis to those with socioeconomic data available, a restricted set of 601 amblyopic participants were compared to 2,404 age-, sex-, and race/ethnicity-matched controls. Comparing cases and matched controls, participants with a diagnosis of amblyopia were significantly more likely to be unemployed (47.8% vs 39.3% [P = 0.0002]), non-home-owners (61.4% vs 55.8 % [P = 0.01]), have Medicaid insurance (33.8% vs 26.2% [P = 0.0002]), or have a household income under $35,000 annually (50.2% vs. 43.2% [P = 0.002]). Multivariable analysis revealed that amblyopic participants were significantly more likely to be unemployed (OR = 1.56; 95% CI, 1.25-1.94; P = 0.00006) and more likely to have Medicaid insurance (OR = 1.43; 95% CI, 1.13-1.82; P = 0.003).

CONCLUSIONS

There are potential long-term socioeconomic associations of amblyopia. Given reported differences in both screening rates and treatment outcomes based on race, ethnicity, and income level, it is vital that future studies adequately portray the diversity of the population through broad, representative recruitment.

Disparities in Amblyopia Treatment Outcomes: The Impact of Sociodemographic Factors, Treatment Compliance, and Age of Diagnosis

PURPOSE

To identify clinical and sociodemographic factors associated with disparities in amblyopia treatment outcomes.

DESIGN

Retrospective chart review.

PARTICIPANTS

Children ≤ 8 years of age diagnosed and treated for unilateral refractive or strabismic amblyopia at our institution from 2012 to 2022.

METHODS

Children with amblyopia were categorized by outcome: resolved amblyopia (< 0.2 logarithm of the minimum angle of resolution [logMAR] interocular difference [IOD] in visual acuity [VA] or no fixation preference in nonverbal patients) or persistent amblyopia. Demographic and clinical data were recorded from the medical record. Zip codes were used to calculate Childhood Opportunity Index (COI) scores, estimated annual household income, and distance to hospital.

MAIN OUTCOME MEASURES

Sociodemographic and clinical factors were compared between children with resolved and persistent amblyopia. Factors significant at P < 0.10 on univariate analysis were included in a multivariable regression model.

RESULTS

A total of 168 patients met inclusion criteria, and 131 patients (78%) had resolved amblyopia. Demographic factors associated with resolution of amblyopia were younger age at diagnosis (3.3 ± 1.7 years vs. 4.5 ± 1.9 years; P = 0.0009), English as the primary language (79.4% vs. 62.2%; P = 0.04), higher estimated annual income ($83 315.93 ± $29 276.64 vs. $71 623.00 ± $26 842.56; P = 0.03), higher COI scores (50.9 ± 27.3 vs. 40.0 ± 26.4; P = 0.03), and living farther from our institution (28.6 ± 37.6 miles vs. 14.9 ± 12.7 miles; P = 0.003). Patients with resolved amblyopia also had higher rates of treatment compliance (83.2% ± 25.0% vs. 75.6% ± 24.4%; P = 0.009) and shorter delays in follow-up (40.1 ± 76.8 days vs. 61.1 ± 90.4 days; P = 0.02). Amblyopia persistence was borderline associated with governmental insurance and higher presenting IOD in VA (both P = 0.06). On multivariate analysis, only younger age at amblyopia diagnosis (P = 0.0010) remained significantly associated with amblyopia resolution.

CONCLUSIONS

Our findings suggest that disparities in amblyopia outcomes are related to differences in age at diagnosis. Interventions to lower the age at which amblyopia is diagnosed, such as programs to improve vision screening rates and access to pediatric eye care in at-risk groups, may directly address inequities in rates of amblyopia resolution.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Factors Associated with Missing Sociodemographic Data in the IRIS® (Intelligent Research in Sight) Registry

Purpose

To describe the prevalence of missing sociodemographic data in the IRIS® (Intelligent Research in Sight) Registry and to identify practice-level characteristics associated with missing sociodemographic data.

Design

Cross-sectional study.

Participants

All patients with clinical encounters at practices participating in the IRIS Registry prior to December 31, 2020.

Methods

We describe geographic and temporal trends in the prevalence of missing data for each sociodemographic variable (age, sex, race, ethnicity, geographic location, insurance type, and smoking status). Each practice contributing data to the registry was categorized based on the number of patients, number of physicians, geographic location, patient visit frequency, and patient population demographics.

Main Outcome Measures

Multivariable linear regression was used to describe the association of practice-level characteristics with missing patient-level sociodemographic data.

Results

This study included the electronic health records of 66 477 365 patients receiving care at 3306 practices participating in the IRIS Registry. The median number of patients per practice was 11 415 (interquartile range: 5849-24 148) and the median number of physicians per practice was 3 (interquartile range: 1-7). The prevalence of missing patient sociodemographic data were 0.1% for birth year, 0.4% for sex, 24.8% for race, 30.2% for ethnicity, 2.3% for 3-digit zip code, 14.8% for state, 5.5% for smoking status, and 17.0% for insurance type. The prevalence of missing data increased over time and varied at the state-level. Missing race data were associated with practices that had fewer visits per patient (P < 0.001), cared for a larger nonprivately insured patient population (P = 0.001), and were located in urban areas (P < 0.001). Frequent patient visits were associated with a lower prevalence of missing race (P < 0.001), ethnicity (P < 0.001), and insurance (P < 0.001), but a higher prevalence of missing smoking status (P < 0.001).

Conclusions

There are geographic and temporal trends in missing race, ethnicity, and insurance type data in the IRIS Registry. Several practice-level characteristics, including practice size, geographic location, and patient population, are associated with missing sociodemographic data. While the prevalence and patterns of missing data may change in future versions of the IRIS registry, there will remain a need to develop standardized approaches for minimizing potential sources of bias and ensure reproducibility across research studies.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Leveraging neural plasticity for the treatment of amblyopia

Amblyopia is a form of visual cortical impairment that arises from abnormal visual experience early in life. Most often, amblyopia is a unilateral visual impairment that can develop as a result of strabismus, anisometropia, or a combination of these conditions that result in discordant binocular experience. Characterized by reduced visual acuity and impaired binocular function, amblyopia places a substantial burden on the developing child. Although frontline treatment with glasses and patching can improve visual acuity, residual amblyopia remains for most children. Newer binocular-based therapies can elicit rapid recovery of visual acuity and may also improve stereoacuity in some children. Nevertheless, for both treatment modalities full recovery is elusive, recurrence of amblyopia is common, and improvements are negligible when treatment is administered at older ages. Insights derived from animal models about the factors that govern neural plasticity have been leveraged to develop innovative treatments for amblyopia. These novel therapies exhibit efficacy to promote recovery, and some are effective even at ages when conventional treatments fail to yield benefit. Approaches for enhancing visual system plasticity and promoting recovery from amblyopia include altering the balance between excitatory and inhibitory mechanisms, reversing the accumulation of proteins that inhibit plasticity, and harnessing the principles of metaplasticity. Although these therapies have exhibited promising results in animal models, their safety and ability to remediate amblyopia need to be evaluated in humans.

Cost-effectiveness of screening for amblyopia among kindergarten children in China

OBJECTIVE

Current cost-effectiveness analyses of amblyopia screening are mainly from western countries. It remains unclear whether it is cost-effective to implement a preschool amblyopia screening programme in China. Our study aimed to evaluate the cost-effectiveness of a hypothetical kindergarten-based amblyopia screening versus non-screening among 3-year-old children.

METHODS

We developed a decision tree combined with a Markov model to compare the cost and effectiveness of screening versus non-screening for 3-year-old children from a third-party payment perspective. The primary outcomes were quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio (ICER). Costs were obtained from expert opinions in different regions of China. Transition probabilities and health utilities were mainly based on published literature and open sources. Sensitivity analyses were performed to assess the impact of parameters' uncertainty on results.

RESULTS

Base-case analysis demonstrated that the ICER of screening versus non-screening was $17,466/QALY, well below the WTP threshold ($38,223/QALY) for China. One-way sensitivity analysis showed that the prevalence of amblyopia, the transition probability per year from untreated amblyopia to healthy, and the discount rate were the top three factors. The likelihood of cost-effectiveness of screening compared with non-screening was 92.56%, according to probabilistic sensitivity analysis. Scenario analysis also indicated that ICER was lower than the WTP threshold even if the time horizon was shortened or the screening was delayed to the age of 4 or 5.

CONCLUSIONS

Amblyopia screening could be considered a cost-effective strategy compared to non-screening for 3-year-old children in China. Screening for children at the age of 4 or 5 may even yield better results.

Race, Ethnicity, Insurance, and Population Density Associations with Pediatric Strabismus and Strabismic Amblyopia in the IRIS® Registry

PURPOSE

To evaluate the associations of sociodemographic factors with pediatric strabismus diagnosis and outcomes.

DESIGN

Retrospective cohort study.

PARTICIPANTS

American Academy of Ophthalmology IRIS® Registry (Intelligent Research in Sight) patients with strabismus diagnosed before the age of 10 years.

METHODS

Multivariable regression models evaluated the associations of race and ethnicity, insurance, population density, and ophthalmologist ratio with age at strabismus diagnosis, diagnosis of amblyopia, residual amblyopia, and strabismus surgery. Survival analysis evaluated the same predictors of interest with the outcome of time to strabismus surgery.

MAIN OUTCOME MEASURES

Age at strabismus diagnosis, rate of amblyopia and residual amblyopia, and rate of and time to strabismus surgery.

RESULTS

The median age at diagnosis was 5 years (interquartile range, 3-7) for 106 723 children with esotropia (ET) and 54 454 children with exotropia (XT). Amblyopia diagnosis was more likely with Medicaid insurance than commercial insurance (odds ratio [OR], 1.05 for ET; 1.25 for XT; P < 0.01), as was residual amblyopia (OR, 1.70 for ET; 1.53 for XT; P < 0.01). For XT, Black children were more likely to develop residual amblyopia than White children (OR, 1.34; P < 0.01). Children with Medicaid were more likely to undergo surgery and did so sooner after diagnosis (hazard ratio [HR], 1.23 for ET; 1.21 for XT; P < 0.01) than those with commercial insurance. Compared with White children, Black, Hispanic, and Asian children were less likely to undergo ET surgery and received surgery later (all HRs < 0.87; P < 0.01), and Hispanic and Asian children were less likely to undergo XT surgery and received surgery later (all HRs < 0.85; P < 0.01). Increasing population density and clinician ratio were associated with lower HR for ET surgery (P < 0.01).

CONCLUSIONS

Children with strabismus covered by Medicaid insurance had increased odds of amblyopia and underwent strabismus surgery sooner after diagnosis compared with children covered by commercial insurance. After adjusting for insurance status, Black, Hispanic, and Asian children were less likely to receive strabismus surgery with a longer delay between diagnosis and surgery compared with White children.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Amblyopia and the whole child

Amblyopia is a disorder of neurodevelopment that occurs when there is discordant binocular visual experience during the first years of life. While treatments are effective in improving visual acuity, there are significant individual differences in response to treatment that cannot be attributed solely to difference in adherence. In this considerable variability in response to treatment, we argue that treatment outcomes might be optimized by utilizing deep phenotyping of amblyopic deficits to guide alternative treatment choices. In addition, an understanding of the broader knock-on effects of amblyopia on developing visually-guided skills, self-perception, and quality of life will facilitate a whole person healthcare approach to amblyopia.