Drying can affect corneal thickness

Corneal thickness can significantly decrease during 1 minute of drying, which may cause an underestimation of applanated pressure as well as central corneal thickness, according to a study.

Volkan Dayanir and colleagues at Adnan Menderes University Medical School in Aydin, Turkey, measured the central corneal thickness of 100 eyes of 100 patients at 0, 15, 30, 45 and 60 seconds. One group of patients was asked to blink between the measurements, while the second group was prevented from blinking.

Corneal thickness did not change significantly in the first group, but significantly decreased in the second group. The rate of thinning increased linearly during the first 30 seconds, then leveled around 0.3 µm/s up to 60 seconds. The decrease in thickness was significant when each time point in the second group was compared to the previous time point.

The study is published in the February issue of Journal of Glaucoma.