Evaluation of Changes in Refractive Error before and after Trabeculectomy and Shunt Surgery

Document Type : Original article

Authors

1 Student Research Committee. Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran

2 Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran

3 Department of Ophthalmology, Farabi Eye Hospital, Tehran University

4 Professor, Department of Basic Sciences, School of Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Abstract

Background and Aims: Studies in the recent years have shown that corneal astigmatism changes occur after trabeculectomy and emphasis on steeping of vertical meridian and inducing With the Rule Astigmatism (WTR) have regulations. The present study was conducted to study the changes in rate astigmatism and its axis, myopia, and hypermetropia in trabeculectomy and shunt surgery.
Materials and Methods: In the present comprative study, two groups of 16 patients with average age of 52.4±8.9 and 94.6±6.7 respectively under trabeculetomy and shunt surgery were recruited. They were studied and compared for changes of refractive error before, 1 week, 1 month, and 3 months after surgery. Data were analyzed using Friedman and Mann-whitney tests.
Results: Averages of Intraocular Pressure (IOP) before, 1 week, 1 month, and 3 were 31.31±7.6, 9.8±2.8, 10.5±1.29, 10.9±1.26 (P<0.05) months after trabeculectomy and 36.06±10.32, 13.5±3.3, 11.68±2.21, 11.18±1.27(P<0.05) after shunt. Also, averages of astigmatism were -1.00±0.59, -6.00±1.9, -2.21±1.18, -1.37±0.62 (P<0.05) in trabeculectomy and -0.89±0.46, -1.56±1.62, -1.51±1.46, -1.07±0.85(P>0.05) in shunt. The percentages of WRT astigmatism in trabeculectomy were 37.5, 100, 37.5, 31.25 and these values in shunt were 43.75, 50, 50, 56.25. In addition, the averages of Equivalane sphere (Es) in trabeculectomy were -0.31±1.49, 1.43±1.94, 0.27±1.74, 0.04±1.46(P<0.05), whereas these values were 0.65±1.5, 1.03±2.03, -.70±1.64, 0.62±1.54 (P<0.05) in shunt. Comparison of astigmatism and axial between trabeculectomy and shunt using Mann-whitney test showed significant changes (P<0.05), but Es was not found to be significantly different (P>0.05).
Conclusion: Both surgery methods induced hypermetropia which decrease with time, but the amount of astigmatism and percentage of WTR astigmatism in trabeculectomy were more than those for shunt surgery.

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The Scientific Journal of Rehabilitation Medicine
Volume 7, Issue 1
March and April 2018
Pages 94-99

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History

  • Receive Date: 19 December 2016
  • Revise Date: 23 January 2017
  • Accept Date: 23 May 2017
  • First Publish Date: 21 March 2018

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