Purpose:
To determine whether vitamin A palmitate can prevent ocularsurface from damages induced by prolonged use of topical antiglaucomatouseyedrops.
Methods:
Sixty eyes of 30 New Zealand white rabbits were randomized to1 of 5 treatment groups: Vitamin A palmitate 1% QD (group 1),timolol maleate 0.5% BID (group 2), brimonidne 0.2% BID (group3), combined Vitamin A palmitate 1% QD with timolol maleate0.5% BID (group 4), or combined Vitamin A 1% QD with brimonidne0.2% BID (group 5) for 30 days. Tear break-up times and basalSchirmer's tests were measured and the conjunctival changeswere determined by impression cytology. Corneal damage was evaluatedby scanning electron microscopy.
Results:
Rabbits in groups 2 and 3 showed statistically significant fewernormal tear break-up time and basal Schirmer's tests than before(P<0.05). Also, in the conjunctival impression cytology,the number of global in the epithelium in groups 2 and 3 wassignificantly lower than before (P<0.05). According to Nelson'smethod, specimens of groups 2 and 3 were graded and scored to1, while groups 1, 4 and 5 were all scored to 0. Corneal damagein groups 2 and 3 assessed with scanning electron microscopyshowed loss of microvilli, increasing number of epithelial holes,cell peeling, loss of hexagonal shape and retraction of cellborders. Ocular surface seemed not to change obviously in group1, 4 and 5.
Conclusions:
1-month treatment with glaucoma medications containing preservativeswithout vitamin A resulted in corneal and conjunctival damage.The long-term use of glaucoma medications with vitamin A mighthelp preserve ocular health.
Keywords: nutritional factors • drug toxicity/drug effects • cornea: epithelium