Evaluation of Corneal Opacities in Patients with Cystinosis by using Anterior Segment Optical Coherence Tomography.

Abstract

Purpose : Cystinosis is a rare lysosomal disease causes various complications by the accumulation of cystine in systemic tissues. The accumulated cystine crystals in cornea and its associated photophobia are considered as useful parameters for diagnosis of the disease. However, no useful method for quantitative evaluation has yet been established. An anterior segment optical coherence tomography (AS-OCT) is being evaluated as a noninvasive diagnostic and screening tool for the detection in such as corneal thickness and opacity.
We evaluated the distribution of corneal reflex intensity (CRI) measured with AS-OCT in patients with cystinosis, and determined the pattern.

Methods : This cross-sectional study evaluated the corneal opacity with the AS-OCT in patients with cystinosis. The study adhered to the tenets of Declaration of Helsinki and was approved by the Institutional Review Board of the NCGM. The CRI of the grayscale images measured with AS-OCT was divided into 256 (0-255) values from black to white. The image intensity value on the one-pixel from corneal epithelium to endothelium at the distance of 1mm or 2mm from the center of the cornea was averaged in 2 cystinosis patients and normal subjects. A correlation between the corneal depth and the CRI was also evaluated.

Results : Case 1 of 17-years-old male with the nephropathic juvenile form, the patients show much slower progression to end-stage renal disease (mild type), and duration of cysteamine therapy was 5 years. Case2 of 32-year-old male with nephropathic infantile form, the patients progress to end-stage renal disease in the first decade of life (severe type), and duration of therapy was 30 years. The mean CRI was 135.6±18.15, 164.8±10.49, respectively, whereas 116.2±20.1 in normal subjects. Although there is no significant difference between normal subject and case1, negative correlation was found in case1 (R = -0.68, p<0001), and no correlation between the corneal depth and the CRI in case2 (R = 0.03, p=0.77).

Conclusions : The evaluation of corneal opacities with AS-OCT is considered as useful procedures in quantitatively assessing corneal opacities in patients with cystinosis.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.