Abstract
Abstract: :
Purpose: Reduced corneal sensitivity has already been proved after PRK. This could be the main reason for a decrease in tear production and for a reduced blinking rate leading to a delayed tear clearance. The aim of this study is to evaluate the efficacy and the compliance of a new oral formulation containing linoleic acid (LA) and gamma-linolenic acid (GLA) (Medilar, Fidia Oftal-B&L, Catania, Italy), precursors of PGE1, on tear production, tear fluorescein clearance and the ocular surface after photorefractive keratectomy (PRK). Methods: Fifty-one subjects (age=25±12 years; refractive error=-3±3 diopters, spherical equivalent) who underwent PRK were enrolled. The inclusion criteria were: Schirmer I test≷10 mm/5min, no corneal fluorescein staining, low irritation symptoms (questionnaire score<5), standardized visual scale (to evaluate tear fluorescein clearance) score<3 (1). The patients were randomly divided into 2 groups. The first group of 26 subjects was treated once daily orally with tablets containing LA (28.5 mg) and GLA (15 mg) (from 3 days before PRK to 1 month after PRK). The second control group (25 subjects) underwent PRK and received no treatment with LA and GLA. Questionnaire score, Schirmer I test and fluorescein clearance test (FCT) using the standardized visual scale were evaluated before starting therapy (T0) and after 30 days from PRK (T1). Results: All patients completed the study. Schirmer I test value varied from 16.3±6.9 (T0) to 17.6±7.2 (T1) for the treated group and from 18.3±6.2 (T0) to 15.7±7.4 (T1) for the untreated group (p<0.0001 between groups, two-tailed unpaired t test). The FCT was 1.9±0.6 at T0 and 1.6±0.8 at T1 for the treated group and 1.7±0.7 at T0 and 2.0±0.9 at T1 for the untreated group (p<0.0001). The questionnaire score was 4.7±1.9 at T0 and 7.6±7.2 at T1 for the treated group and 4.2±2.0 at T0 and 10.1±7.6 at T1 for the untreated group (p<0.05). Conclusion: Oral administration of the PGE1 precursors, LA and GLA, has shown to be effective in increasing tear production and clearance after PRK. Furthermore, according to the patients’ judgement, the new drug formulation (tablets) had a much better compliance than the old formulation (sachets). 1. Macri A, Rolando M, Pflugfelder SC. A Standardized Visual Scale for Evaluation of Tear Fluorescein Clearance. Ophthalmology 2000 Jul;107(7):1338-43.
Keywords: 552 refractive surgery: PRK • 376 cornea: tears/tear film/dry eye • 492 nutritional factors