J Németh1, B Erdélyi, B Csákány. 1. Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
Abstract
PURPOSE: To examine the effect of a short pause in blinking on the quantitative topographic parameters of the corneal surface. SETTING: Refractive corneal surgery unit of a university eye hospital. METHODS: Using a TMS-1 instrument (Computed Anatomy, Inc.), corneal topographic parameters were measured 5 and 15 seconds after a complete blink in 12 healthy subjects. The main outcome measures were changes in the surface regularity index (SRI) and the surface asymmetry index (SAI). RESULTS: During the pause in blinking, the mean SRI value increased from 0.18 +/- 0.19 (SD) to 0.30 +/- 0.19 (P <.02) and the SAI from 0.21 +/- 0.08 to 0.24 +/- 0.10 (P =.079, not statistically significant). There were no significant changes in the values for potential visual acuity, corneal refractive power, or astigmatism. CONCLUSION: The results indicated a significant change in corneal topography during even a short pause in blinking. In follow-up studies using corneal topography, all measurements should be done at a fixed time after a complete blink.
PURPOSE: To examine the effect of a short pause in blinking on the quantitative topographic parameters of the corneal surface. SETTING: Refractive corneal surgery unit of a university eye hospital. METHODS: Using a TMS-1 instrument (Computed Anatomy, Inc.), corneal topographic parameters were measured 5 and 15 seconds after a complete blink in 12 healthy subjects. The main outcome measures were changes in the surface regularity index (SRI) and the surface asymmetry index (SAI). RESULTS: During the pause in blinking, the mean SRI value increased from 0.18 +/- 0.19 (SD) to 0.30 +/- 0.19 (P <.02) and the SAI from 0.21 +/- 0.08 to 0.24 +/- 0.10 (P =.079, not statistically significant). There were no significant changes in the values for potential visual acuity, corneal refractive power, or astigmatism. CONCLUSION: The results indicated a significant change in corneal topography during even a short pause in blinking. In follow-up studies using corneal topography, all measurements should be done at a fixed time after a complete blink.