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L.H. Panchal, T. Schroeder Swartz, M. Wang; Comparison of Outcomes in Patients With Single versus Double Intacs Corneal Ring Segments . Invest. Ophthalmol. Vis. Sci. 2006;47(13):4334.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the efficacy and visual outcome of single versus double INTACS corneal ring segments
Retrospective chart review of 40 eyes of 36 patients who underwent INTACS corneal ring segment placement. Twenty–one eyes had double segments (double group) while 19 had single segment placement (single group). Of 36 patients (40 eyes), 25 had keratoconus, 6 had Pellucid Marginal Degeneration (PMD), 4 had irregular astigmatism, and 1 had myopia. Main outcome measures include best corrected visual acuity (BCVA), change in spherical equivalent, change in refractive astigmatism, and patient satisfaction. The BCVA, change in astigmatism and spherical equivalent were evaluated by t–test.
The average postoperative follow–up period was 27 weeks (range: 12 – 56 weeks). In reference to BCVA, the double group improved from 20/60 (Ave) to 20/30– (Ave) while the improvement in the single group was comparable (from 20/60 (Ave) to 20/40 (Ave)). Myopic spherical equivalent (SE) was reduced by 2.50+0.60D in the double group while the single group had a slightly more reduction of 3.50+0.23D, though the difference is not statistically significant (P = 0.3). Astigmatism was decreased by 0.75+0.04D in the double group, and the single group showed a statistically significantly more reduction of 1.75+0.15D (p = 0.006). All patients were satisfied with the results of the procedure with improved contact lens fitting and vision (scored 2.75 (Ave) out of 0 to 3).
Single Intacs segment appears to be more efficacious than double segment. While single and double improve BCVA equally, single shows a statistically significantly more reduction in astigmatism than double. In addition, single also shows a trend of slightly more reduction in myopic spherical equivalent than double though the difference in SE reduction between these two groups did not reach statistical significance in this study.
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