[OCT3 exploration of anterior segment]

Abstract

Purpose: Posterior pole imaging with OCT3 provides macular scans with a very high resolution. Use of OCT1 has already been described for anterior segment imaging. This work presents the advantages of OCT3 in anterior segment imaging compared to UBM (50 MHz) and 20-MHz ultrasound imaging with long focal distance (patent pending PCT/FR98/02788).

Material: and methods: We used an OCT3 unit dedicated to the posterior pole. By defocusing the laser beam we obtained high-resolution scans of the cornea, angle, lens and IOLs. Fifty-seven eyes (35 patients) were imaged by OCT3 and high-resolution ultrasound in cases of corneal dystrophy, corneal transplant, LASIK, narrow angle, iris bowing, etc.

Results: In all cases OCT3 provided high-resolution information with a limit of penetration at the posterior part of the iris. This limitation was not observed with ultrasound imaging. Nevertheless, OCT3 is a useful tool for corneal imaging in cases of opacities limiting biomicroscope imaging. OCT3 corneal scans at high resolution make it possible to identify the corneal interface in lamellar transplants or LASIK. With a narrow angle, a dynamic test of angle closure can be done. With iris bowing, OCT3 can differentiate iris cysts and iris tumors. Anterior chamber IOLs can be imaged with their relationships to anterior segment structures.

Conclusion: OCT3 provides non-contact anterior segment imaging with high resolution but with a limit of penetration given by posterior part of the iris.