Comparative Evaluation of Topographic Characteristics in Bilateral Keratoconus with Unilateral Corneal Vogt’s Striae: A Contralateral Eye Study

Document Type : Original Article

Authors

1 Department of Ophthalmology, Cornea Specialist, Cornea Research Center, Khatam‐Al‐Anbia Hospital, Mashhad University of Medical Sciences, Mashhad, Iran

2 Department of Optometry, Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran

3 Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran

4 Department of Optometry, Zahedan University of Medical Sciences, Zahedan, Iran

5 Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran

Abstract

Purpose:
The aim of this study was to evaluate and compare topographic characteristics in bilateral keratoconus (KCN) patients with unilateral Vogt’s striae. 
Methods:
In this prospective cross-sectional contralateral eye study, the KCN patients that were enrolled in this study had a reliable diagnosis of bilateral clinical KCN with unilateral Vogt`s striae based on slit-lamp signs, as well as corneal topographic/tomographic maps. All the cases underwent a comprehensive ophthalmic examination, including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA),cycloplegic refraction (calculated by vectorial analysis), and placido disc-based Tomey topographer (TMS-4; Tomey, Germany). In this study, clinical and topographic characteristics of all cases were evaluated and compared between the contralateral KCN eyes with Vogt`s striae and those without Vogt`s striae. Paired sample t-test was used to compare the parameters with a normal distribution and the Wilcoxon signed rank test was used to compare the non-parametric parameters. P-value Results:
Fifty patientsaged 20 to 38 years (27.43±5.46) were recruited in this study. Our results showed that there were significant differences in sphere, cylinder, spherical equivalent, UDVA, CDVA and J0 (all p<0.001) except for J45 (p=0.58) between the contralateral eyes of KCN patients. In KCN eyes with Vogt’s striae, flat (46.48±3.33 vs 44.44±2.22, p<0.001), steep (52.48±4.39 vs 47.02±3.26, p<0.001), minimum (46.36±3.37 vs 44.35±2.17, p<0.001) and average keratometry (49.27±3.96 vs 45.74±2.60, P<0.001) as well as Surface Regularity Index (1.39±1.12 vs 0.52±0.41, p<0.001), Surface Asymmetry Index (2.32±1.25 vs 1.42±1.04, P<0.001), Keratoconus Index (75.07±28.83 vs 48.01±33.52, p<0.001) and Keratoconus Severity Index (65.88±22.25 vs 38.61±29.40, p<0.001)were higher than the contralateral eye without Vogt’s striae.
Conclusion:
Corneal topographic parameters showed a significant difference between the contralateral KCN eyes with and without Vogt’s striae. These results should be noticed in clinical evaluations and treatments of KCN patients.

Keywords

Main Subjects

References

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Journal of Paramedical Sciences & Rehabilitation
Volume 7, Issue 3
September 2018
Pages 7-16

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