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Effect of corneal drying on central corneal thickness
Volkan Dayanir1, Rabia Sakarya, Fatih Ozcura
1Department of Ophthalmology, Adnan Menderes University Medical School, Aydin, Turkey. vdayanir@adu.edu.tr
Journal of Glaucoma
|January 6, 2004
Summary
Corneal drying significantly reduces central corneal thickness, potentially leading to inaccurate applanation pressure measurements. This study quantifies the thinning effect over 60 seconds without blinking.
Area of Science:
- Ophthalmology
- Corneal Physiology
- Ophthalmic Instrumentation
Background:
- Corneal thickness is a critical parameter in ophthalmic assessments.
- Applanation tonometry relies on accurate central corneal thickness (CCT) measurements.
- The impact of corneal drying on CCT and its implications for tonometry require investigation.
Purpose of the Study:
- To quantify corneal thinning caused by induced corneal drying.
- To evaluate the potential consequences of this thinning on applanation pressure readings.
Main Methods:
- Ultrasonic pachymetry was used to measure CCT in 100 eyes over 60 seconds.
- Two groups were studied: one with voluntary blinking and one with a 60-second blink-hold.
- Corneal thickness changes were recorded at 15-second intervals.
Main Results:
- Corneal thickness did not significantly change with voluntary blinking.
- Significant corneal thinning occurred in the blink-hold group, decreasing by 3.0% over 60 seconds.
- The rate of thinning increased linearly for the first 30 seconds and then plateaued.
Conclusions:
- Prolonged corneal drying can significantly reduce CCT.
- This reduction in CCT may lead to an underestimation of intraocular pressure when using applanation tonometry.
- Clinicians should consider the potential impact of corneal dehydration on pressure measurements.