Abstract
Purpose: :
To determine the reliability of non–contact tonometry (NCT) in measuring intraocular pressure (IOP) over a combination of amniotic membrane (AM) patch and therapeutic soft contact lens (TSCL) in normal human eyes.
Methods: :
Twenty–five healthy volunteers (20 males, 5 females) participated in this study. After topical anesthesia, IOP was measured using non–contact tonometry before and after the application of a single–layer of AM to the right eye and a double–layer of AM to the left eye. To enable the IOP measurement by NCT, a TSCL was placed over the AM patch. The thickness of a single– or a double–layer of AM was measured by pachymetry and correlated with the IOP reading.
Results: :
We found no statistical difference between IOPs measured with and without a combination of a single–layer AM/TSCL (P = 0.734). In contrast, the IOPs measured over a combination of a double–layer AM/TSCL decreased significantly when compared to the control (P < 0.0001). The average thicknesses of the single– and the double–layer of AM were 72.4 ± 15.0 µm and 126.9 ± 14.6 µm (mean ± SD), respectively. There was a negative correlation between total AM thickness and IOP change (r = –0.481, P = 0.0008).
Conclusions: :
We found that it is reliable to measure IOP by NCT through a combination of a single–layer AM/TSCL on normal human eyes. However, IOP measured by NCT over a combination of a double–layer AM/TSCL was inaccurate and tended to be an underestimation.
Keywords: cornea: clinical science • intraocular pressure • contact lens