Spectral Domain Optical Coherence Tomographic Analysis Of The Ocular Equator

Abstract

Purpose: To analyze and describe the external layers of normal eyes with spectral domain optical coherence tomography (SD-OCT) performed approximately at the ocular equator.

Methods: Retrospective, observational and descriptive analysis of ten eyes of 10 healthy ocular patients. 6 mm anterior segment SD-OCT scans were performed in three locations: 1: at the corneo-scleral limbus, with the limbus in the middle of the scan, visualizing cornea and esclera; 2: posterior to the border of the corneo-scleral limbus; 3, approximately at 5 mm off the limbus, with the scan directed posteriorly. Scans were performed at the nasal and temporal sides of each eye (3 and 9 o’clock meridians). Findings were observed and described.

Results: Visualization of the following structures was accurately performed: conjuntiva, Tenon’s capsule, extra-ocular muscles, and sclera. After correct identification of the layers, thickness measurement was performed with the manual caliper software. Histopathology correlation was done as a comparison to identify each structure.

Conclusions: Ab-externo, in vivo analysis with SD-OCT of outer ocular layers can be correctly performed. SD-OCT can be used to accurately identify and evaluate the conjuntiva, insertion of extra-ocular muscles and characteristics of the sclera.

Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 550 imaging/image analysis: clinical • 521 extraocular muscles: structure