4. Discussion
inflammation, astigmatism, glaucoma, keratoconus, early-moderate
RECRUITMENT, INFLAMMATION, ASTIGMATISM, EYE DISEASES, DRY EYE, NON-PROLIFERATIVE DIABETIC RETINOPATHY, MEIBOMIAN GLAND DYSFUNCTION, DIABETIC MACULAR EDEMA, KERATOCONUS, GLAUCOMA, OXIDATIVE STRESS
This prospective randomized study conducted in patients with keratoconus stages I-III of the Amsler–Krumeich classification was designed to assess whether the antioxidant and anti-inflammatory effects of the omega-3 fatty acid, DHA, may result in an amelioration of some ophthalmological parameters recorded by corneal topography as compared to patients who did not receive the nutraceutical supplementation. The duration of the study was 3 months. The effect of DHA on concentrations of biomarkers of oxidative stress and inflammation in blood samples was also evaluated.Changes in keratometry parameters were not observed in any of the study groups when readings at the end of the study were compared with baseline. The astigmatism axis did not show within-group differences, but there were between-group differences at baseline and at the end of the study, with higher values in the control group. Similar findings in relation to the asphericity coefficient were found. In subjects assigned to the control group, there was a significant increase in CCT at the end of the study, whereas an increase in CCT was not observed among DHA-treated patients. The IOP measured by Goldmann applanation tonometry showed a decrease in the DHA group, which almost reached statistical significance (In line with the antioxidative and anti-inflammatory effects of DHA, we found significant differences in the comparison between the study groups regarding plasma levels of TAC, MDA, free GSH, and GSH/GSSG ratio, as well as reduced values of inflammatory markers, including IL-4, IL-6, and VEGF-A. These observations are consistent with data obtained in previous studies carried out in different eye diseases (such as non-proliferative diabetic retinopathy, diabetic macular edema, dry eye, meibomian gland dysfunction, or exfoliative glaucoma) with the use of this highly concentrated DHA triglyceride as a nutraceutical supplement [Overexpression of tear inflammatory cytokines in patients with keratoconus has been reported in different studies [In addition to the impossibility of assessing concentrations of inflammatory markers in tear samples, limitations of the study include the single-center design, the small study population, and the short duration of supplementation (only 3 months). Recruitment of eligible patients was also difficult due to the impact of the COVID-19 pandemic on healthcare. Novelty of the study, however, relies on the fact that supplementation with a highly concentrated DHA product in patients with keratoconus has not been previously evaluated. Topical omega-3 PUFA proved to be beneficial in association with a faster regeneration of corneal nerve fibers in patients with keratoconus after epithelium-off corneal collagen cross-linking [Although a significant effect of DHA supplementation in the overall amelioration of corneal topography parameters was not observed, it may be argued that the antioxidant and especially the anti-inflammatory effects of DHA may not be sufficiently selective for clinical detection when targeting specific underlying mechanisms involved in early-moderate stages of keratoconus. On the other hand, it is also possible that DHA supplementation for only 3 months may be a short time to elicit clinically apparent changes. Although the mean age of the patients was 31 years, it is important to note that the patients with keratoconus aged about 20 are in a quick progress process and should be instructed about the risk of progression associated with age.Based on the present preliminary results, a multicenter study extended for more than 1 year would be helpful to assess the long-term effect of DHA supplementation in patients with keratoconus. An international follow-up study would be particularly desirable as keratoconus parameters differ in different ethnicities [