Ocular Cystinosis Experience in Southwestern Ontario.

PURPOSE: To evaluate ocular treatment adherence and its impact on clinical outcomes in patients with cystinosis in southwestern Ontario, where the disease incidence is higher due to a founder effect in the Old Order Amish population.

METHODS

This was a retrospective case series of patients with ocular cystinosis seen at Victoria Hospital and the Ivey Eye Institute at St Joseph's Health Care in London, Ontario, Canada, from 2008 to 2023. The authors investigated the demographics, ocular manifestations, and visual outcomes and characteristics in pediatric patients with ocular cystinosis. They also conducted qualitative analysis to characterize medication compliance and identify treatment barriers to compliance.

RESULTS

This study included 14 patients with ocular cystinosis. In southwestern Ontario, the incidence of cystinosis is approximately 1 in 4,700 live births. Most patients were Old Order Amish, with a family history of cystinosis and consanguineous parents. During treatment, patients were typically asymptomatic, but photophobia was the most reported symptom. Slit-lamp examination revealed cystine crystals in the cornea of all patients; however, best corrected visual acuity and intraocular pressure were unremarkable in every case. A Fisher's exact test revealed a trend toward lower compliance in Amish patients compared to non-Amish patients (odds ratio: 0.067, P = .103). Significant treatment barriers for patients with ocular cystinosis were identified, including compliance issues with frequent eye drop regimens, educational and financial burdens, and geographical and cultural challenges, all impacting patient care and follow-up.

CONCLUSIONS

This study highlights the need for improved strategies to improve treatment compliance and overcome barriers to care for patients with ocular cystinosis, particularly within the Old Order Amish population in southwestern Ontario, to ensure better clinical outcomes and quality of life. [J Pediatr Ophthalmol Strabismus. 2025;62(2):105-115.].