Excimer laser photorefractive keratectomy for high myopia: four-year experience with a multiple zone technique.

PURPOSE: The purpose of the study is to evaluate the results of the authors' 4-year experience with excimer laser photorefractive keratectomy (PRK) and multiple optical zone corneal ablation in highly myopic eyes. METHODS: The authors retrospectively evaluated 56 eyes of 44 patients (mean refraction, -11.3 diopters [D]; range, -5.75 to -24.5 D) who underwent PRK with a Visx Model 20/20 laser (Visx, Santa Clara, CA). Preoperative visual acuity of 20/40 or better was present in 46 eyes. Corneal ablation was divided into concentric optical zones (4, 5, and 6 mm), allowing corrections of up to 18 D, with a refractive goal of within -1 D from emmetropia in 49 eyes. A hand-held fixation system was always used, and a nitrogen-blowing system (NBS) was used in the first 21 eyes only. RESULTS: Before retreatment, the range of final cycloplegic refraction from emmetropia in eyes treated with NBS versus not was within +/-1 D in 6 (28.6%) and 15 eyes (44.1%), between -1.25 and -3 D in 5 (23.8%) and 14 eyes (41.1%), and more than -3 D in 10 (47.6%) and 5 eyes (14.7%), respectively. No lines of visual acuity were lost in 37 eyes (80.4%) with 20/40 or better visual acuity before surgery. Three eyes showed vision loss due to worsening of myopic maculopathy and one due to corneal haze. Correction stabilized within 9 months, and at a mean time of 25.6 months, the correction attained was of -8.5 +/- 3.6 D, achieving 90.3% of attempted correction. Eyes with preoperative myopia less than -10 D (n = 27) showed regression less than -1 D in 8 eyes (29.6%), between -1.25 and -3.00 D in 5 eyes (18.5%), and greater than -3.00 D in 1 eye (3.7%); eyes with more than -10 D (n = 29) regressed in 3 (10.3%), 6 (20.7%), and 1 eye (3.4%), respectively. Severe haze was observed in 11 eyes (19.6%) 3 months after surgery. Two eyes showed decentration greater than 1.5 mm. At last examination, night driving problems were reported by 12 (41.4%) of 29 patients evaluated who drive. CONCLUSIONS: After the NBS was eliminated, the multiple-zone technique achieved a long-term, stable 83.1% reduction of preoperative myopia. Patients with severe myopia appreciated reduction of most of the refractive defect, although perception of halos was noted by 16 patients.

The monochromatic green argon laser in the management of macular disorders.

The authors have been using an argon laser photocoagulator equipped with a green filter for about 21/2 years. Compared to the usual blue-green argon laser, the advantage of such an instrument is that green radiation is not absorbed to any significant degree by macular pigment. This ensures a selective action on hemoglobin and pigment epithelium. The green wavelength appears to be extremely useful in the management of macular disorders. The authors report the criteria they follow and the technique they use in the treatment of subretinal neovascular membranes and of macular edema arising from different retinal vascular disorders.

Argon laser photocoagulation in the management of retinal detachment and predisposing lesions.

During the years 1979-1982 we treated by argon laser photocoagulation 863 eyes of 551 patients affected by peripheral retinal degenerations and breaks. No case of progression to retinal detachment has been registered so far. In the same period, we treated 42 patients affected by retinal detachment of different topography (three posterior pole and 39 peripheral detachments) and size (mostly limited detachments, 12 as large as a quadrant, two larger than a quadrant). In 41 of these 42 eyes, the retina is still firmly attached after a 1- to 4-year follow-up, while in one case it was necessary to proceed surgically following a relapse. While argon laser photocoagulation is certainly the first choice treatment of retinal degenerations and breaks, it also appears to be a reliable alternative to scleral buckling in the management of specific cases of retinal detachment.