Measurement of Depth of Intacs

A recent article explores the use of Intacs in keratoconus:

Measurement of Depth of Intacs Implanted Via Femtosecond Laser Using Pentacam
Journal of Refractive Surgery Vol. 25 No. 4 April 2009

Günhal Kamburoglu, MD; Aylin Ertan, MD and Osman Saraçbasi, PhD

Thirty-two eyes of 23 keratoconic patients receiving Intacs intrastromal corneal ring segments implanted by femtosecond laser were included in the study. The depth of intracorneal channel and Intacs segments were measured for 7 predetermined points at 1 week and 1 year postoperatively using Scheimpflug images.
Mean achieved intrastromal channel depth exceeded the intended parameter by 6.5 µm to 69.0 µm. The standard deviation varied between ±13.5 µm and ±44.2 µm. The segment depth decreased at the end of the first postoperative year in all measured points, and the change was statistically significant at the superior, inferior, and temporal sides of the Intacs. The degree of change was not correlated with size of the Intacs, preoperative central corneal thickness, and mean keratometric values.

CONCLUSIONS
Intacs started out deeper than intended and tended to shallow over time. I had one patient who had erosion of their Intac segment into their anterior chamber which may have been a result of deeper than intended placement. This study has important implications for surgeons who perform Intacs in the treatment of keratoconus.