Abstract
Purpose: :
To investigate Intacs ring segment depth with a high–speed corneal and anterior segment optical coherence tomography (CAS–OCT) system.
Methods: :
A prospective, nonrandomized, clinical case series of patients receiving intrastromal corneal ring segments (Intacs) for the management of keratoconus between November 1st, 2004 and August 1, 2005. All cases in which CAS–OCT was performed within the first six weeks post–operatively were included.
Results: :
Four eyes of four patients were included. Slit–lamp impression of depth was inexact, with the observer using a different reference point in assessing depth in shallow–placed segments versus deep–placed segments. Using a stepwise multivariate analysis, we found the distal portions of the ring segment (p<.003) and segments place in the inferior cornea (p<.04) were significantly shallower as a fraction of the total corneal thickness. Shallower depth was associated (p<.04) with greater fractional anterior stromal compression.
Conclusions: :
Shallower Intacs segments may experience more complications such as epithelial/stromal breakdown and extrusion due to the greater anterior stromal compression. The distal and inferior portion of Intacs tend to be shallower. OCT provides precise assessment of ring segment depth and may help identifying implants at greater risk of depth–related complications.
Keywords: keratoconus • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical