Application of rapid scanning retinal thickness analysis in retinal diseases

Purpose: The authors have further developed their method of retinal thickness analysis to rapidly generate multiple optical cross sections of the retina and provide thickness maps at the posterior pole. The potential use of this method was evaluated in a number of macular disorders. Methods: A commercial prototype of the scanning retinal thickness analyzer was used to examine patients with a variety of macular diseases. A laser slit beam was projected on the retina and scanned across a 2- x 2-mm retinal area in 200 to 400 msec. The images of the intersection of the laser slit beam with the retina were recorded digitally and used for visualization of disease. Nine scans were combined, and an operator-free algorithm generated a three-dimensional thickness map at the posterior pole. Results: Cysts could be visualized in macular edema associated with diabetes mellitus and with retinal vein occlusion. The retinal thickness map quantitated the location, extent, and height of the edema. In serous detachment, the extent and the height of the retinal pigment epithelial elevation could be documented. In cases of suspected macular holes and pseudoholes, the diagnosis was considered more reliable than with conventional biomicroscopy. The extent of epiretinal membranes, the sites of adherence, and associated intraretinal cystic changes were identified. In glaucoma, the anatomic course of localized loss of neuronal retinal tissue could be traced. Conclusions: Scanning retinal thickness analysis provided multiple optical cross sections of the retina and yielded information useful in the diagnosis and monitoring of macular diseases. The three-dimensional thickness map provided quantitative information that may be useful for clinical management.