To the Editor.
—Ablation of the superficial cornea with the 193-nm excimer laser is being performed in clinical trials for correction of myopia (photorefractive keratectomy)1 and for removal of superficial corneal opacities and surface irregularities (phototherapeutic keratectomy).2 According to some of these protocols, a vacuum fixation ring is placed on the limbus; this ring allows the surgeon to control fixation of the globe during surgery and blow air over the surface of the cornea, removing debris liberated during the ablation procedure.1 Similar vacuum fixation devices have been used for other surgical corneal procedures, such as myopic keratomileusis, and have been shown to generate markedly elevated intraocular pressures (in excess of 65 mm Hg) that might be dangerous if sustained for prolonged periods.3 To assess the potential for elevation of intraocular pressure during excimer laser superficial keratectomy, we measured the pressure in four eyes before and
McDonnell PJ, Moreira H, Garbus J, Trokel S, Clapham TN, D'Arcy J. Intraocular Pressure Changes due to Vacuum Fixation Ring During Excimer Laser Corneal Surgery. Arch Ophthalmol. 1991;109(4):467. doi:10.1001/archopht.1991.01080040027012