The effect of artificial tears on corneal epithelial thickness profile changes after PRK by corneal epithelial mapping.
Mehdi Khodaparast1 , Seyed-Farzad Mohammadi2 , Hesam Hashemian1 , Samaneh Azizi1 , Hooman Ahmadzadeh1 , Masoud Khorrami-Nejad3 *
- Farabi Eye Hospital, Tehran University of Medical Sciences
- Translational Ophthalmology Research Center, Farabi Eye Hospital
- Tehran University of Medical Sciences, School of Rehabilitation
Abstract: Refractive surgeries have reached great popularity among patients and physicians alike in recent years. Lubricant drops are frequently used after refractive surgeries. Accurate evaluation of the corneal epithelium thickness provides important information about corneal healing process. To date no studies have evaluated the effects of lubricant drops on corneal thickness.
Methods: This study was performed on 142 PRK patients without dry eye. Corneal epithelial thickness profile was obtained before, and one, three and six months after surgery using the RTvue-100 (Optovue, Fremont, CA) in 2 mm central zone, 2-5 mm, 5-7 mm, and 7-9 mm regions. Patients were randomly divided into two groups: group A (71 patients) who were treated with preservative-free artificial tears (Sina Daru, Iran) and group B (68 patients) who did not receive artificial tears.
Results: 1 month after PRK, epithelial thickness of both groups showed a significant decrease compared to preop values. Group A had greater epithelial thickness, in 0-2 and 2-5 rings. In 3 months, in group A epithelial thickness was increased which was significantly higher than baseline in central and 2-5 rings, increase was milder in outer rings. In group B thickness was increased up to baseline levels in all regions. Group A had greater epithelial thickness compared to group B, in 0-2, 2-5, 5-7, and 7-9 at 3 months postop. In the 6 month follow up, epithelial thickness showed a continued trend of increasing. Central and 2-5 ring of group B increased to higher than baseline levels. 5-7 and 7-9 rings of both groups only increased up to the baseline levels. The two groups had no significant differences at this follow up.
Overall post-PRK thickness was decreased at 1 month then increased in later follow ups. Increase was greater in 0-2 and 2-5 rings which was up to higher than baseline levels, compared to peripheral rings which increased only up to baseline levels. Group A showed a faster increase, but there was no significant difference between two groups in the final follow up.
Conclusion: Results of this study show that lubricant drops may increase the speed of epithelial recovery in post-PRK patients.
