Peripheral Retinal Imaging Using A Prototype Anterior Segment OCT/SLO

Abstract

Purpose: : To investigate the utility of a prototype Anterior Segment OCT/SLO system for imaging normal anatomy and pathologic lesions of the peripheral retina and pars plana.

Methods: : Patients were positioned in the chinrest in front of the non–contact AC Cornea OCT System (Ophthalmic Technologies Inc. [OTI], Toronto, Ontario, Canada), and were instructed to fixate at an internal or external target. The 1300nm light source was centered over the area of interest, and a series of images were captured.

Results: : 30 patients with variety of peripheral retinal and pars plana lesions were examined in the study. Lesions imaged included peripheral cystoid degeneration and retinoschisis, retinal tears and scleral buckles, and sclerotomy sites. Imaging was ideal for lesions in the region within 15mm of the corneal limbus. It was also useful for scanning through opaque corneas and scleras, as well as for imaging implants or foreign bodies in this region. Maximum field of view was 15mm x 15mm. Scanning depth was up to 15mm, while scanning width was up to 20mm. The axial resolution was <10microns, whereas transverse resolution was <20microns. A 2x zoom feature was useful for examining details of specific small areas of interest. The measurement function provided data on lesion thickness and distance from the ora serata, and dimensions of normal and pathologic structures. While, the imaging of the ciliary body was limited due to its vascularity, structures located more posteriorly were well defined . Overall, the procedure required minimal operator training, and was well tolerated by the majority of patients.

Conclusions: : The Anterior Segment OCT/SLO System offers a uniquely non–invasive high–resolution technique for examining the anterior portion of the retina and pars plana. The non–contact aspect of procedure was particularly useful for evaluation of post–operative patients. Its ability to generate coronal scans as well as cross–sectional scans provided unique views of lesions in this region of the eye.

Keywords: retinal detachment • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retinal neovascularization