Repeated Measurements of the Anterior Segment During Accommodation Using Long Scan Depth Optical Coherence Tomography

Objectives The aim was to determine the repeatability of ultralong scan depth spectral-domain optical coherence tomography (SD-OCT) measurements of the ocular anterior segment during accommodation. Methods The center wavelength of the SD-OCT light source was 840 nm with a bandwidth of 50 nm. The ocular axial resolution of the system was approximately 6.0 &mgr;m, and the scan depth was 7.2 mm in air. Twenty eyes of 20 healthy subjects were imaged with a custom-built, ultralong scan depth SD-OCT during 2 visits. The anterior segment images were acquired during nonaccommodative and maximal accommodative states. After image processing and correction, the true values of the morphometric dimensions of the anterior eye were obtained. The variables of the two states from two visits were compared. Results For the corrected anterior segment images, the variables did not significantly differ from one visit to the next. The values of anterior chamber depth, pupil diameter, and the radius of the lens anterior surface curvature during accommodation were significantly smaller than those during the nonaccommodative state. The lens thickness significantly increased with accommodation. There was no significant difference in the posterior surface curvature of the lens between the two states. Conclusions Ultralong scan depth SD-OCT holds promise for quantifying dimensional changes in the eye during accommodation. The instrument demonstrated good repeatability of ocular anterior segment dimensional measurements during accommodation.