Axial lengths in a cohort of patients with a range of inherited retinal disease

Abstract

Purpose : Inherited retinal diseases (IRDs) are frequently associated with refractive error, usually resulting from an abnormally long or short axial length (AL). We investigated AL distributions in patients with particular IRD subtypes.

Methods : We analyzed axial lengths measured by partial coherence interferometry (IOLMaster optical biometer, Carl Zeiss Meditec AG, Jena, Germany) from patients recruited from the IRD clinics of Moorfields Eye Hospital London as part of a wider imaging study. Patients had a clinical IRD diagnosis with molecular confirmation in most cases. Distributions of AL for each IRD (where measurements >10 patients were available) were examined and comparison made against a normative database of AL from a cohort with a similar median age (Raine Study, Australia). Firth’s logistic regression models for an AL greater than or equal to 26mm and less than or equal to 21mm were constructed with adjustment for age and sex in unrelated individuals, and only inclusive of males in the case of X-linked IRDs.

Results : 342 patients from 51 families with sixteen different IRDs were examined (median age 19.2yrs IQR 13.1-30.5; 63% male; mean AL 24.11mm SD 1.94). For 7 IRDs, we had data on >10 individuals: ABCA4 (n=74, mean AL 23.68mm), Blue Cone Monochromatism (BCM) (n=12, mean AL=26.02), Bornholm Eye Disease (BED) (n=13, mean AL = 26.54), CNGA3 (n=23, mean AL =23.91), CNGB3 (n=39, mean AL =23.19), RPE65 (n=25, mean AL = 23.27), and RPGR(n=58, mean AL = 24.75). The Raine Study included 1335 unrelated individuals (median age 19.9yrs IQR 19.7-20.3; 51% male; mean AL 23.60mm SD 0.93). Compared with this cohort, significantly increased odds for longer AL were observed for BCM (OR 34.7 p<0.001), BED (OR 80.4 p<0.001), RPGR (OR 6.1 p<0.001) and RPE65 (OR 6.7 p=0.004). Patients with variants in RPE65 also had increased odds for short AL (OR 12.5 p<0.001).

Conclusions : We identified longer mean ALs in patients with BED, BCM and RPGR-associated disease. Interestingly patients with RPE65-associated disease had increased odds for both longer and shorter AL (although the average AL of these patients was shorter than that for the reference cohort). Exploration of axial lengths in patients with specific defects in retinal signaling can shed light on processes driving development of refractive error as well as yielding a more complete description of disease phenotypes and visual impairment.

This is a 2021 ARVO Annual Meeting abstract.