Optical Coherence Tomography of Intacs
A 55-year-old woman who had uneventful implantation of 0.35 mm Intacs to correct myopia (manifest refraction −3.50 +0.25 × 95, uncorrected visual acuity 20/125, best corrected visual acuity 20/20) was imaged with optical coherence tomography (OCT) (Humphrey Systems, Inc.) to assess ring segment position and corneal architecture 27 months postoperatively. The 4.00 mm scanning line of the unit was focused on the corneal surface to obtain images along the same section plane at multiple levels.1
Optical coherence tomography obtained high-resolution images in a noncontact fashion. The position of the Intacs and the changes in the surrounding stromal tissue were visualized. The segments' depth were at two thirds stromal thickness and caused slight indentation of the underlying corneal tissue toward the anterior chamber. The anterior chamber angle configuration was not affected. Temporal to the nasal segment at about 2 o'clock, highly reflective signals were detected, corresponding to the location of the deposits (Figure 1).
Improved knowledge of the structure of the cornea following Intacs placement surgery should allow us to evaluate the mechanism of action of the ring segments better, as well as to recognize their short-term and long term effects on corneal structure and architecture. With the use of OCT in this patient, we were able to obtain high-resolution images of the cornea, the ring segments, and channel deposits in vivo in a noncontact fashion. This information can help plan the postoperative management of patients, as well as determine the progression of the changes induced within the cornea such as channel deposits.
Ömur Ö. Uçakhan MD
Celso Tello MD
Jeffrey M. Liebmann MD
Robert Ritch MD
Penny A. Asbell MD
aNew York, New York, USA
© 2001 by Lippincott Williams & Wilkins, Inc.
1. Hee MR, Izatt JA, Swanson EA, et al. Optical coherence tomography of the human retina. Arch Ophthalmol 1995; 113:325-332