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E. Valas Teuma, Liz Dumanoir, Aissatou Barry, Gary Gray, G. Brock Magruder, Steve Bott; Clear Corneal Incision: Sealability of the Manual Versus LensAR laser generated Full Thickness Incision. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1643. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
The human cornea has the ability to self-seal after penetrating incision wounds. The purpose of this work is to compare the sealability of clear corneal incisions (CCIs) created by manual means to those generated by the LensAR Laser System - fs 3D (LLS-fs 3D).
A total of 22 human donor globes were used for this experiment. The laser CCIs, were performed using the LLS-fs 3D. Standard three-plane CCIs were used for both the manual and laser CCIs. Post incisions, a high resolution Fourier domain optical coherence tomography (OCT) system was used to measure the incision geometry. After the OCT measurements, the sealability of the CCIs was measured using a digital pressure gauge. The Seidel test was utilized to detect a leak of the aqueous onto the cornea. A computer-controlled stepper motor is used to push the plunger into the eye. The IOP reported by the pressure gauge is recorded at the first sign of leakage. If the IOP reaches 500 mmHg without leakage, the test is considered complete.
One tailed t-tests of the sealability of the manual versus laser CCIs, indicate that the mean IOP at which leakage occurred was the statistically the same for the two cases (p = 0.061). However, variability of IOP at leakage for the laser was significantly less than for the manual (±28 mmHg vs. ±94 mmHg). Regarding the measured incision geometries, the geometric parameters measured for the laser incisions were always at least as good in accuracy and precision as the manual and in several cases was superior. For example, a two tailed t-test of the mid-tunnel depth location versus target (50%) indicates that the laser incision was statistically significantly closer to the target value than the manual incisions (mean 46% vs. 33%, p=0.26).
The IOP at leakage of laser versus manual CCIs were statistically the same. However, an F-test of the variance of the IOP elevation at which leakage occurred showed that the manual method produced incisions with statistically higher variance than those of the laser CCIs. OCT measurements showed that the mean value of the location of the mid-plane of the three-plane CCI was placed significantly closer to the target placement for the laser versus the manual CCIs. Overall, the testing showed that the manual and laser methods are statistically equivalent in sealability but that the laser method produces more consistent wound geometry.
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