Alterations of the ocular surface after advanced surface ablation of the cornea: a three-month follow-up study

Poster Details

First Author: N.Garc SPAIN

Co Author(s):    G. Melvi Murillo   J. Nieto   M. Gonzalez   M. Calonge   M. Maldonado  

Abstract Details

Purpose:

Dry eye disease (DED) is one of the most frequent complications after corneal refractive surgery in the early months after surgery. It is estimated in several studies that between 32 and 60 percent of subjects undergoing LASIK (Laser in situ keratomileusis) develop symptoms and signs of DED after surgery. Currently, there are some alternative procedures of excimer laser corneal refractive surgery that are believed to carry a lower risk of inducing DED due to the intraoperative technique. The aim of this study was to assess the impact of advance corneal surface ablation (ASA) with excimer laser on different diagnostic DED tests and in corneal sensitivity, and to analyze the evolution at three months postoperatively.

Setting:

IOBA, University of Valladolid,Spain.

Methods:

We randomly selected ten eyes of ten patients before corneal refractive surgery (ASA) with an average age (32.87 ± 4.9) years (range: 27-43). Following tests were performed: Uncorrected distance visual acuity (VA), mechanical and thermal corneal sensitivity, Ocular Surface Disease Index (OSDI), tear osmolarity (Tearlab®), conjunctival hyperemia, tear film breakup time (BUT), corneal fluorescein and conjunctival Lissamin green staining. All data were collected preoperatively, one month and three months after surgery.

Results:

Uncorrected visual acuity improved significantly during the first month (p = 0.005) and remained without changes at 1 month and at 3 months. Symptoms decreased during the first month compared to baseline (p = 0.05), remaining stable thereafter (this could be due to an over use of contact lens of all patients before the surgery). We found a significant decrease in conjunctival staining with lissamine green at the first month (p = 0.046) with respect to baseline, which increased at the third month (p = 0.014). The osmolarity increased between the preoperative measurement and the first month value, and significantly decreased in the third month (p = 0.009). Regarding corneal sensitivity, corneal mechanical threshold increased in the first month recovering its initial value at the third month. The heat thermal corneal threshold progressively decreased compared to preoperative values in the first and third month after surgery (p = 0.036 and p = 0.007 respectively), cold thermal threshold increased in the first month, without showing statistically significant differences, however, it declined significantly (p = 0.025) between the first and third postoperative months. The values of conjunctival hyperemia, BUT, corneal fluorescein staining and Schirmer test were unchanged throughout the monitoring period.

Conclusions:

In the current research, we found statistically significant changes in the subjective score values of dry eye (OSDI), tear osmolarity (values normalized at the third month of monitoring) and in thermal corneal sensitivity (which persisted at the third month). To the best of our knowledge, this is the first investigation to report such findings regarding tear osmolarity and thermal corneal sensitivity. More follow-up of these patients is needed to determine when these results return to the preoperative values. FINANCIAL DISCLOSURE?: No