April 2009
Volume 50, Issue 13
ARVO Annual Meeting Abstract  |   April 2009
Topographic Effects of Large-Diameter Intrastromal Corneal Ring Segments in Small-Diameter Channels
Author Affiliations & Notes
  • B. H. Jeng
    Ophthalmology, University of California San Francisco, San Francisco, California
  • L. Valverde
    Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio
  • W. J. Dupps, Jr.
    Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio
  • Footnotes
    Commercial Relationships  B.H. Jeng, None; L. Valverde, None; W.J. Dupps, Jr., None.
  • Footnotes
    Support  NIH KL2 RR024990 (BHJ, WJD) and Research to Prevent Blindness Challenge grant (BHJ, WJD).
Investigative Ophthalmology & Visual Science April 2009, Vol.50, 1760. doi:
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    • Get Citation

      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.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose: : 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.

Methods: : 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.

Results: : 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.

Conclusions: : 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.

Keywords: cornea: clinical science 

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