LIMITATIONS OF IMAGING CHOROIDAL TUMORS IN-VIVO BY OPTICAL COHERENCE TOMOGRAPHY

Background: Optical coherence tomography (OCT) produces two-dimensiona l cross-sectional images with a longitudinal resolution of 10 mu m. It s capacity for imaging retinal structure has been shown in a variety o f diseases. There are no reports on its capacity and limitations in im aging choriocapillary and choroidal structures. Methods: Twenty-two pa tients with the diagnosis of malignant melanoma of the choroid were su bmitted to OCT. We used a prototype and a commercial device, both with an 850-nm superluminescent diode with a bandwidth of 30 nm (reported longitudinal resolution 10 mu m). The images were evaluated for retina l thickness, changes in retinal pigment epithelium, subretinal fluid a ccumulation and changes in choriocapillary or choroidal reflectivity. Results: Retinal edema and detachment found on biomicroscopic examinat ion for fluorescein angiography was detected by OCT in all such cases. In 2 of 22 cases small retinal detachments were detected only by OCT. Tumor extension through the retinal pigment epithelium was not seen i n this series, either by biomicroscopy or by OCT. The pat tern of chor oidal or choriocapillary reflectivity was nonspecifically lower than t hat of normal choroid, but did not yield any additional information ab out tumor histology. When normal retina was present, the OCT appearanc e of a malignant melanoma resembled that of normal choroid. Conclusion : OCT may provide information about the retinal structure overlying pr ominent tumors and the extent of adjacent retinal detachment. In its p resent state of development, OCT is of little value in the differentia l diagnosis of choroidal tumors. Its potential value for the follow-up of shallow tumors needs further investigation.