Early ocular surface and tear film status in congenital aniridia indicates a supportive treatment window

Abstract

Aim To evaluate changes in the ocular surface and tear film with age and mutational status in congenital aniridia. Methods 45 participants with congenital aniridia (89 eyes) in a prospective, cross-sectional study. Whole-exome sequencing identified the causative mutation. Examinations included slit-lamp biomicroscopy, in vivo confocal microscopy, Ocular Surface Disease Index (OSDI) score, blink rate, Schirmer I test, Oxford Staining Score (OSS), tear film break-up time (TFBUT) and Ocular Protection Index (OPI). Results There were age-dependent increases in OSDI (β=0.34, 95% CI 0.03 to 0.66; p=0.030), blink rate (β=0.18, 95% CI 0.08 to 0.27; p<0.001) and OSS (β=0.05, 95% CI 0.03 to 0.07; p<0.001) and age-dependent reductions in tear production (β=-0.23, 95% CI -0.43 to 0.02; p=0.029) and TFBUT (β=-0.10, 95% CI -0.17 to -0.04; p<0.001). Perturbed OSDI, OSS, blink rate, tear production and TFBUT were noted after the age of ten and OSDI, OSS, blink rate and TFBUT correlated with deficient corneal nerves and limbal stem cell function. OSDI, blink rate, Schirmer, OSS, TFBUT and OPI were not associated with type of PAX6 mutation, but OSDI, OSS and blink rate associated with grade of aniridia-associated keratopathy. Conclusions Ocular surface damage and dry eye signs appear in congenital aniridia regardless of mutation, appearing after 10 years of age and progressing thereafter. An early treatment window may exist for therapies to protect the ocular surface homoeostasis and limbal function, to possibly delay keratopathy development and progression.