Anterior chamber intraocular lens for high myopia: five year results.

PURPOSE: To evaluate the effectiveness of the surgical correction of high myopia 5 years after anterior chamber intraocular lens (IOL) implantation and to analyze the lens position and related complications. SETTING: Federal University of São Paulo-Escola Paulista de Medicina, São Paulo, Brazil. METHODS: This prospective study comprised 26 eyes that were implanted with an anterior chamber IOL (model ZB5M) and had a minimum follow-up of 5 years. Before and after surgery, manifest and cycloplegic refractions were done; slitlamp examination was performed; anterior chamber depth was measured; and keratometry, ophthalmoscopy, and central corneal endothelial cell count were performed. At the last follow-up, computerized biomicroscopy of the anterior segment was also done. RESULTS: The spherical equivalent decreased from -16.5 diopters (D) +/- 4.1 (SD) preoperatively to -0.9 +/- 0.9 D postoperatively. At the last examination, 57.7% of eyes had a spherical equivalent refraction within +/-1.0 D of emmetropia. Of eyes with a preoperative best spectacle-corrected visual acuity of 20/40 or better, 73.3% had an uncorrected visual acuity of 20/40 or better postoperatively. The mean tilt caused by the IOL was 4.4 +/- 2.7 degrees (range 0.5 to 12.2 degrees) and the mean IOL decentration, 0.3 +/- 0.2 mm (range 0.02 to 0.8 mm). The mean decrease in the endothelial cell count was 1.5%, with a mean cell density of 2808 +/- 305 cells/mm2 preoperatively and 2765 +/- 242 cells/mm2 postoperatively. Pupillary ovalization was observed in 12 eyes (46.1%). CONCLUSIONS: The anterior chamber IOL safely and effectively corrected high myopia.

Laser in situ keratomileusis for undercorrection after radial keratotomy.

PURPOSE: To assess the safety and efficacy of excimer laser in situ keratomileusis (LASIK) in treating residual myopia and/or astigmatism following refractive keratotomy. METHODS: Fourteen eyes that had previously undergone radial and/or arcuate keratotomy were included. The surgeries were performed using the Chiron Automated Microkeratome and the VISX 20/20B excimer laser. RESULTS: Average follow-up was 12.64+/-5.02 months. Mean spherical equivalent refraction was reduced from -3.48+/-3.52 D preoperatively to -0.04+/-0.87 D postoperatively. At the last follow-up examination there were 8 eyes (57.1%) with a refraction within+/-0.50 D, and 10 eyes (71.4%) within +/-1.00 D of emmetropia. Uncorrected visual acuity was 20/20 or better in 4 eyes (28.6%) and 20/40 or better in 10 eyes (71.4%). Vector analysis of the astigmatic correction showed an index of success of 80%. There was no significant loss (> or = or =2 lines) of spectacle-corrected visual acuity. We observed interface epithelial ingrowth in one eye. CONCLUSIONS: The correction of residual myopia and/or astigmatism with LASIK in eyes with prior refractive keratotomy proved to be safe and effective. Careful preoperative evaluation may help to avoid complications such as reopening of incisions during surgery or postoperative ingrowth of epithelium beneath the corneal flap.

Laser in situ keratomileusis to correct refractive errors after keratoplasty.

PURPOSE: To assess the safety and effectiveness of excimer laser in situ keratomileusis (LASIK) to correct refractive myopia, astigmatism, or both after keratoplasty. SETTING: Eye Clinic Day Hospital, São Paulo, Brazil. METHODS: Twenty-two eyes that had previously had corneal transplantation were studied. Laser in situ keratomileusis was performed using the Chiron automated microkeratome and the VISX Twenty-Twenty B excimer laser. RESULTS: Mean follow-up after LASIK was 10.09 months +/- 3.87 (SD). The spherical equivalent refraction dropped from -4.55 +/- 3.66 D before LASIK to -0.67 +/- 1.24 D after surgery. At the last examination, 72.7% of patients had a refractive error within +/- 1.00 D of emmetropia and 54.5% had uncorrected visual acuity of 20/40 or better. Vector analysis of astigmatic correction showed an index of success of 54.0%. Best spectacle-corrected visual acuity was unchanged in 8 cases, improved in 9, and decreased in 5. Significant endothelial cell loss, keratoplasty wound dehiscence, and other serious complications did not develop in any eye. CONCLUSION: The correction of refractive error with LASIK in postkeratoplasty patients proved to be safe, effective, and predictable. Further studies with longer follow-up are needed to determine the method's clinical value.

Intrastromal corneal ring: 12-month sighted myopic eyes.

BACKGROUND: To evaluate the efficacy, predictability, and stability of the refractive effect produced by the Intrastromal Corneal Ring (ICR), the authors completed a 12-month study on 10 myopic eyes. METHODS: Ten patients with preoperative refractive errors ranging from -2.63 diopters (D) to -4.25 D (mean, -3.30 D) participated in the study. The attempted correction was -2.50 D for a 7.0-mm diameter, 0.3-mm thick ICR. One eye of each patient received an ICR. RESULTS: The average change in spherical equivalent at 12 months was -2.25 D (SD 0.54 D; range, -1.62 to -3.25 D). All patients maintained a spectacle-corrected visual acuity of 20/20 or better during the 12-month study period, with the exception of patient no. 6 who saw 20/30 at the 6-month examination. Her spectacle-corrected visual acuity returned to 20/20 a few days after the ICR was explanted and remained stable throughout the study. Uncorrected visual acuity had improved to 20/40 or better in all patients on postoperative day 1 and remained in this range for the 9 eyes (90%) during the 12 months of follow up. At postoperative month 12, 9 of 9 eyes (100%) had an uncorrected visual acuity of 20/40 or better with 3 of 9 eyes (33%) seeing 20/20 or better. The remaining patient, no. 6, experienced a tear in Descemet's membrane during the procedure and required explantation of the ring after 6 months due to induced astigmatism and deterioration of uncorrected visual acuity. Two patients developed infiltrates that resolved with the use of antibiotics. The most common postoperative ocular findings were peripheral corneal haze in all eyes that diminished over time, minute lamellar channel deposits (7 of 10 eyes, 70%), deep stromal neovascularization (5 of 10 eyes, 50%), and pannus (5 of 10 eyes, 50%). CONCLUSION: This preliminary study shows that implantation of an intrastromal corneal ring of this dimension (0.3-mm thick) can reduce approximately 1.50 to 3.00 D of myopia and maintain spectacle-corrected visual acuity.

Intrastromal corneal ring--one-year results of first implants in humans: a preliminary nonfunctional eye study.

BACKGROUND: The Intrastromal Corneal Ring (ICR) is a new investigational medical device designed to alter corneal curvature without surgical intervention in the central cornea. The ring is inserted between the layers of the stroma in the cornea's periphery at two-thirds depth through an approximately 2-millimeter incision. METHODS: To investigate the safety and refractive effect of implanting an ICR of a given thickness (0.30 mm) and outer diameter (7.70 mm) into human corneas, an ICR was implanted into one nonfunctional eye of each of three patients during the period of March to May, 1991. One predesignated ICR was successfully explanted 5 months after implantation to evaluate the feasibility of ICR removal and to observe the effect of ring removal on corneal curvature. Patients were followed for 1 year after the initial implant procedure. RESULTS: The three implant procedures and postoperative courses proceeded without any significant complications. Approximately 2.00 D of central corneal flattening was achieved in all eyes. No adverse reactions or other medically-significant complications were observed over a 1-year follow-up period. The patient who underwent ICR removal experienced no perioperative complications, and the patient's cornea has remained stable with a return to its preoperative curvature. CONCLUSION: Although this study is preliminary and limited in scope, we have demonstrated that the ICR can be tolerated safely in the human cornea and results in a flattening of the corneal curvature that is stable for up to a year after insertion. The successful removal of the ICR begins to establish reversibility of the procedure and induced refractive effect.