Double-blind corticosteroid trial in identical twins following photorefractive keratectomy.
The use of topical corticosteroids following excimer laser photorefractive keratectomy (PRK) is widespread, but the role of corticosteroids remains poorly defined. The purpose of this study was to evaluate the use of different corticosteroid postoperative regimens following 193-nanometer excimer PRK in identical twins. Preoperatively, cycloplegic refraction of the left eye of each twin measured -3.00 D sphere. The full correction was treated utilizing the identical technique within the same 30 minute period. The study was conducted in a double-blind fashion and the refraction, corneal clarity, uncorrected and best spectacle corrected visual acuity, and keratometry were assessed over the 6-month study period. Both twins were placed on an identical regimen, tapering their drops over a 3-month period. Corneal clarity was remarkably well preserved with essentially clear corneas observed in both twins. Similarly, both twins achieved 20/15 vision with a cycloplegic refraction of +0.75 D at 6 months. The only difference in the healing pattern was the slightly more rapid visual recovery in twin A. The code was revealed upon the cessation of corticosteroid regimen. Twin A had received fluoromethalone 0.1% and Twin B received dexamethasone 0.1%. Keratometry demonstrated identical flattening. There were no corticosteroid induced intraocular pressure rise or other complications noted. Identical twins presented a unique opportunity to better understand wound healing following laser keratectomy. The results of this limited study indicated that for at least lower degrees of myopia the need for full strength topical corticosteroids remains questionable.
Windsor Laser Eye Institute, Ontario, Canada.
J J
JJ
Machat
D000328:Adult; D003315:Cornea / Q000601:surgery*; D003907:Dexamethasone / Q000008:administration & dosage*; D004200:Diseases in Twins; D004311:Double-Blind Method; D005469:Fluorometholone / Q000008:administration & dosage*; D006801:Humans; D053685:Laser Therapy; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000517:prevention & control* / Q000601:surgery*; D009883:Ophthalmic Solutions; D011183:Postoperative Complications / Q000517:prevention & control*; D012029:Refraction, Ocular; D014430:Twins, Monozygotic; D014792:Visual Acuity; D014945:Wound Healing
D009883:Ophthalmic Solutions; D003907:Dexamethasone; D005469:Fluorometholone