Purchase this article with an account.
B. H. Jeng, L. Valverde, W. J. Dupps, Jr.; Topographic Effects of Large-Diameter Intrastromal Corneal Ring Segments in Small-Diameter Channels. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1760.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To compare the topographic effects of same-diameter (6.0 mm) versus larger-diameter (6.8 mm) intrastromal corneal ring segments (Intacs; Addition Technology, Inc., Fremont, CA) inserted into 6.0-mm diameter intrastromal channels.
Donor eye study with serial same-eye controls (n=5). Intraocular pressure was maintained at 15±2 mmHg during all measurements by vitreous infusion. Intacs were inserted into two 6.0-mm inner diameter channels that were created with standard Intacs mechanical corneal separators. Simulated keratometry values (Keratron Scout; Optikon, Roma, Italy) were recorded before channel creation, after insertion of 6.0-mm diameter Intacs segments, and after 6.0-mm diameter Intacs segments were replaced with 6.8-mm diameter Intacs segments.
Central corneal curvature decreased from 43.44±1.73D preoperatively to 34.40±2.29D after insertion of 6.0-mm Intacs segments (p<0.0001). Central corneal curvature decreased to 32.44±1.70D after insertion of 6.8-mm Intacs segments into the same 6.0-mm channels, although the incremental change was not significant (p=0.14). Corneal astigmatism in these eyes increased from 1.08±0.32D at baseline to 1.98±1.74D (p=0.11) after insertion of 6.0-mm diameter segments and to 3.57±1.06D (p=0.004 compared to baseline) after insertion of 6.8-mm diameter segments.
In a pilot donor eye study, intrastromal corneal ring segments with a diameter greater than the intrastromal channel diameter produced significant astigmatic effects and demonstrated a trend toward greater flattening compared to the effects of placing segments with the same diameter as the intrastromal channels.
This PDF is available to Subscribers Only