Artificial Tear Drops Influence on High Order Aberrations in Healthy Eye Subjects
Fouad Chraibi *
Department of Ophthalmology, University Hospital Hassan II, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
Chaimae Khodriss
Department of Ophthalmology, University Hospital Hassan II, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
Ahmed Bennis
Department of Ophthalmology, University Hospital Hassan II, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
Meriem Abdellaoui
Department of Ophthalmology, University Hospital Hassan II, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
Idriss Andaloussi Benatiya
Department of Ophthalmology, University Hospital Hassan II, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
*Author to whom correspondence should be addressed.
Abstract
Purpose: To gain more insight into tear film from a functional standpoint, we investigate artificial tear eye drops effect by assessing its influence on high order aberration in healthy eye subjects using a Shack-Hartmann aberrometer.
Methods: An observational case-control study into which 20 young healthy participants were involved. High order aberrations were measured using Shack-Hartmann technology before; 1 hour and 3 hours after instillation of a 0.3% sodium hyaluronate eye drop.
Main measured outcomes were root mean square of high order aberrations in central 5 mm (HOA 5) and in central 6 mm (HOA 6), spherical aberration, vertical coma, horizontal coma, vertical trefoil, horizontal trefoil.
Results: The HOA 5 mean value was 0.21µ before the instillation of artificial tear eye drops and 0.185µ one hour after instillation with a significant statistical difference (p=0.01) and 0.186µ three hours after instillation with no significant statistical difference (p=0.057). No significant statistical difference was found for HOA 6 before and after tear eye drops application.
Vertical coma was the only subset of high order aberrations that was significantly improved from 0.042µ to -0.003µ one hour after tear eye drops application (p=0.04). There was no statistical difference for all the other measurements.
Conclusions: Some high order aberrations could arise from the tear film even in a healthy patient. Vertical coma could be used as a tool to point to the integrity of tear film. For wavefront-guided refractive surgery candidates, high order aberrations should be assessed 1 hour after artificial tear drop instillation.
Keywords: Artificial tear eye drops, healthy eye subjects, high order aberrations, vertical coma.