PT  - JOURNAL ARTICLE
AU  - Rebecca R. Mastey
AU  - Katie M. Litts
AU  - Christopher S. Langlo
AU  - Emily J. Patterson
AU  - Margaret R. Strampe
AU  - Joseph Carroll
TI  - Interocular Symmetry and Repeatability of Foveal Outer Nuclear Layer Thickness in Congenital Achromatopsia
AID  - 10.1101/367813
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 367813
4099  - http://biorxiv.org/content/early/2018/07/12/367813.short
4100  - http://biorxiv.org/content/early/2018/07/12/367813.full
AB  - Purpose To examine the intraobserver repeatability of foveal outer nuclear layer (ONL) thickness measurements and evaluate interocular symmetry for patients with achromatopsia (ACHM) and controls.Design Cross-sectional study.Subjects Sixty-four patients with CNGA3- or CNGB3-associated ACHM and 38 patients with normal vision were recruited for analysis.Methods Horizontal line scans through the fovea of each eye were acquired using optical coherence tomography. Three foveal ONL thickness measurements were made by a single observer using custom software to analyze repeatability. Interocular symmetry was assessed using the average of the three measurements for each eye.Main Outcome Measures The main parameter being measured is foveal ONL thickness.Results Mean (± SD) foveal ONL thickness for ACHM patients was 74.86 ± 17.82μm (OD) and 75.30 ± 15.68μm (OS) compared to 110.60 ± 15.67μm (OD) and 110.53 ± 13.91μm (OS) for controls. Foveal ONL thickness did not differ between eyes for ACHM (p = 0.821) or control patients (p = 0.961). Intraobserver repeatability was high for foveal ONL measurements in ACHM patients (ICC = 0.939, OD and 0.915, OS) and controls (ICC = 0.991, OD and 0.984, OS).Conclusions Foveal ONL thickness can be measured with excellent repeatability. While foveal ONL thickness is reduced in ACHM compared to controls, the high interocular symmetry indicates that contralateral ONL measurements could be used as a negative control in early-phase monocular treatment trials.Financial Disclosures: J. Carroll: MeiraGTx (Consultant), AGTC (Research Support), OptoVue (Research Support)Precise: (21/35 Submitted separately as ‘Highlights’ file) We examined the intraobserver repeatability and interocular symmetry of foveal outer nuclear layer (ONL) thickness measurements in patients with congenital achromatopsia.