Adaptative Optics Imaging of Macular Microholes

Abstract

Purpose: : To image the photoreceptor (PR) defect in eyes with microholes , using an Adaptative Optics .

Methods: : A 59–year–old woman presented with a minor visual disturbance in the right eye (RE). Best corrected Snellen visual acuity was 20/32 in the right eye (RE) and 20/20 in the left eye (LE). Biomicroscopy fundus examination showed a microhole appearance in the RE but no abnormality in the LE. The macula was then examined with t Stratus OCT 3 (Zeiss Meditec,Dublin), and an Adaptative Optics (AO) prototype. OCT examination consisted of 6 radial scans, 6mm long. The length of the break in the Inner Segment/Outer Segment of the photoreceptors (IS/OS PR) was measured with calipers. The AO prototype had the following characteristics: enface resolution of 3 µm using a pupil diameter of 7 mm, image recording with a CCD camera, retina illumination with a time–gated incandescent source at a rate of 4/s. After the acquisition of single images, a composite image was constructed by treating a stack of images covering a surface of 300µm.

Results: : The mean length of the break in the IS/OS PR line measured with OCT was 118 µm in the RE and 74 µm in the LE. The Adaptative Optics composite image showed a dark central area of 150×220 µm in the RE and of 110×100 µm in the LE. No details of the photoreceptors were detectable in this area. In both eyes the size of this dark central area of PR loss seen on AO was comparable to the size of the break in the IS/OS PR line measured with OCT. Outside this area the mosaic of photoreceptors was present.

Conclusions: : In a case of macular microhole, we were able to show that the break in the IS/OS PR line seen on OCT, corresponded to the loss of photoreceptors shown on the image of Adaptative Optics.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • macular holes • imaging/image analysis: clinical