Optical coherence tomography artifacts predict adaptive optics scanning light ophthalmoscopy success in achromatopsia

Abstract

Purpose : The relatively low success of acquiring adaptive optics scanning light ophthalmoscopy (AOSLO) images from subjects with achromatopsia (ACHM) has largely been attributed to the presence of nystagmus in these patients.¹ The ability to predict which patients will yield successful AOSLO images would be valuable for clinical trials by reducing costs and decreasing patient burden. Here we examined whether artifacts in optical coherence tomography (OCT) images could be used to predict the success or failure of AOSLO imaging in subjects with ACHM.

Methods : One eye from 66 subjects with genetically-confirmed ACHM (15 CNGA3 and 51 CNGB3; 30 females and 36 males) was imaged with OCT (Cirrus, 512x128 macular cube) and non-confocal split detection AOSLO. OCT artifacts in the reconstructed vertical volume from the macular cube were graded into 1 of 4 categories: 1) none or minimal, 2) clear and low frequency, 3) low amplitude and high frequency, and 4) high amplitude and high frequency. Each vertical volume was graded once by two observers. A third observer graded any discrepancies and reviewed any additional volumes when needed to reach a consensus, which was used for subsequent analyses. AOSLO success was defined as sufficient image quality in split detector images at the fovea to assess cone quantity.

Results : There was near perfect agreement between the two observers for assessing the OCT artifact grade (kappa = 0.86). AOSLO was successful in 31/66 (47%) subjects. For subjects with grade 1 OCT artifacts, AOSLO success was 65% (22/34 subjects); grade 2 was 47% (8/17 subjects); grade 3 was 11% (1/9 subjects); and grade 4 was 0% (0/6 subjects). There was a significant association between OCT artifact grade and AOSLO success (p = 0.0002, Chi-squared test).

Conclusions : Subjects with less severe OCT artifacts are most likely to be good candidates for AOSLO imaging. As these OCT artifacts are typically due to the presence of nystagmus, more direct measures of nystagmus (e.g., pupil tracking) may show higher predictive power. Nonetheless, our results may be useful in guiding patient selection for AOSLO imaging in clinical trials for ACHM.

¹PMID: 27479814

This is a 2020 ARVO Annual Meeting abstract.