Interocular Symmetry and Repeatability of Foveal Outer Nuclear Layer Thickness in Congenital Achromatopsia

Abstract

Cone Photoreceptors 18 19Precise: (21/35 Submitted separately as "Highlights" file) We examined the intraobserver 20 repeatability and interocular symmetry of foveal outer nuclear layer (ONL) thickness 21 measurements in patients with congenital achromatopsia. . CC-BY-NC 4.0 International license It is made available under a was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint (which . http://dx.doi.org/10.1101/367813 doi: bioRxiv preprint first posted online Jul. 12, 2018; Purpose: To examine the intraobserver repeatability of foveal outer nuclear layer (ONL) 25 thickness measurements and evaluate interocular symmetry for patients with achromatopsia 26 (ACHM) and controls. 27Design: Cross-sectional study. 28 Subjects: Sixty-four patients with CNGA3-or CNGB3-associated ACHM and 38 patients 29 with normal vision were recruited for analysis. 30Methods: Horizontal line scans through the fovea of each eye were acquired using 31 optical coherence tomography. Three foveal ONL thickness measurements were made by a 32 single observer using custom software to analyze repeatability. Interocular symmetry was 33 assessed using the average of the three measurements for each eye.

Adaptive Optics Retinal Imaging inCNGA3-Associated Achromatopsia: Retinal Characterization, Interocular Symmetry, and Intrafamilial Variability

“…3B). Previously reported mean ± SD from unaffected controls for ONL thickness is 110.6 ± 15.7 μm, with an n = 38 (mean age ± SD; 28.8 ± 10.9 years);46 these values are significantly higher than our reported values for CNGA3 -ACHM ( P < 0.0001, t = 8.37, df = 74). ONL thickness at the fovea was measured with standard OCT.…”

Characterization of Retinal Structure in ATF6-Associated Achromatopsia

“…Foveal ONL thickness was highly variable in the seven cases studied, ranging from 39.22 to 174.04 μm, and the mean ± SD foveal ONL thickness for ATF6 -ACHM was 95.23 ± 41.88 μm. As shown in Figure 2, this was slightly lower than previously reported values for controls (110.60 ± 15.67 μm) 24. However, due to the small number of subjects with ATF6- ACHM and the larger range in their ONL thickness, this was not significant ( P = 0.3215, Dunn's multiple comparisons test).…”

“…In addition, only grade 3 and grade 4 EZ disruption was observed in direct contrast to CNGA3 - and CNGB3 -ACHM, in which all five EZ grades were observed 20,21,47. In previous work, 2% to 15% of subjects with CNGA3- and CNGB3 -ACHM had grade 3 EZ disruption and 24% to 31% had grade 4 20,21,24. Further disorganization was observed at the fovea including hyperreflectivity of the ONL (MM_0043, MM_0044) and apparent thickening of the ELM (MM_0152, JC_11438).…”

“…In summary, grade 1 corresponds to a continuous EZ band, grade 2 is EZ disruption, grade 3 is the absence of the EZ band, grade 4 is the appearance of a hyporeflective zone, and grade 5 is outer retinal atrophy. Foveal ONL thickness—defined as the distance between the inner limiting membrane and external limiting membrane (ELM) in the case of complete foveal excavation or the distance between the outer plexiform layer and ELM in the case of incomplete foveal excavation 20,21 —was evaluated using OCT Reflectivity Analytics (ORA) software 24,28. Foveal hypoplasia, defined as the presence of one or more inner retinal layers through the fovea, was also assessed 18,20,29.…”

“…In subjects with CNGA3 - or CNGB3 -associated ACHM (abbreviated CNGA3 -ACHM and CNGB3 -ACHM, respectively) the EZ band at the fovea is disrupted or absent in approximately 68% of cases 20,21. The thickness of the ONL is also significantly reduced in CNGA3 - and CNGB3 -ACHM, although there is substantial variability among subjects 20,21,24. Another imaging tool—adaptive optics scanning light ophthalmoscopy (AOSLO)—enables noninvasive, cellular resolution imaging of the rod and cone photoreceptor mosaic.…”