1/763. Clinical features and surgery for acquired progressive esotropia associated with severe myopia. PURPOSE: The purpose of this study was to evaluate the clinical and physiological findings and to determine the most appropriate surgical procedure for acquired progressive esotropia with severe myopia. methods: Thirty-eight cases of acquired progressive esotropia with severe myopia were examined to evaluate their clinical and physiological findings. All cases were divided into four groups according to the limitation of their abduction. The eyeball in group IV is fixed in an extremely adducting position. Thirty-one cases underwent strabismus surgery; medial rectus muscle recession and lateral rectus muscle resection in 23 cases, transposition of superior and inferior rectus muscles (modified Jensen procedure included) in eight cases. RESULTS: The medial rectus muscle recession with the lateral rectus muscle resection procedure was effective in the early stage of acquired progressive esotropia patients. Transposition procedure was effective in the severe abducting limited patients. CONCLUSIONS: As the recession & resection procedure is easier than the transposition procedure, we recommend performing surgery in the earlier stage of the abducting disorder before the eyeball is fixed in an extremely adducting position. ( info) |
2/763. Very high-frequency ultrasound corneal analysis identifies anatomic correlates of optical complications of lamellar refractive surgery: anatomic diagnosis in lamellar surgery. OBJECTIVE: To examine the utility of very high-frequency (VHF) ultrasound scanning in determining the anatomic changes and correlates of optical complications in lamellar refractive surgery. STUDY DESIGN: Case series. PARTICIPANTS: Cases analyzed included marked asymmetric astigmatism postautomated lamellar keratoplasty (ALK), image ghosting despite normal videokeratography post-ALK, uncomplicated myopic laser in situ keratomileusis (LASIK), and hyperopic LASIK with regression. methods: A prototype VHF ultrasound scanner (50 MHz) was used to obtain sequences of parallel B-scans of the cornea. Digital signal processing techniques were used to measure epithelial, stromal, and flap thickness values in a grid encompassing the central 4 to 5 mm of the cornea, enabling pachymetric mapping of each layer with 2-micron precision. MAIN OUTCOME MEASURE: The appearance of the corneas in VHF ultrasound images and thickness values of individual corneal layers determined from VHF ultrasound data. RESULTS: VHF ultrasound resolved the epithelial, stromal cap, or flap and residual stromal layers 1 year after lamellar surgery. Asymmetric stromal tissue removal was differentiated from stromal cap irregularity. epithelium acted to compensate for asymmetry of the stromal surface about the visual axis and for localized surface irregularities. Irregularities in the epithelial-stromal interface accounted for image ghosting present despite apparently normal videokeratography. Epithelial thickening was shown after uncomplicated myopic LASIK. Hyperopic LASIK demonstrated relative epithelial thickening localized to the region of ablation accounting for refractive regression. CONCLUSIONS: VHF ultrasound shows promise as a sensitive method of determining the anatomic correlates of optical complications in lamellar refractive surgery. ( info) |
3/763. Streptococcal keratitis after myopic laser in situ keratomileusis. A 24-year-old healthy male underwent uncomplicated laser in situ keratomileusis (LASIK) in left eye. One day after the surgery, he complained of ocular pain and multiple corneal stromal infiltrates had developed in left eye. Immediately, the corneal interface and stromal bed were cleared, and maximal antibiotic treatments with fortified tobramycin (1.2%) and cefazolin (5%) were given topically. The causative organism was identified as 'streptococcus viridans' both on smear and culture. Two days after antibiotic therapy was initiated, the ocular inflammation and corneal infiltrates had regressed and ocular pain was relieved. One month later, the patient's best corrected visual acuity had returned to 20/20 with -0.75 -1.00 x 10 degrees, however minimal stromal scarring still remained. This case demonstrates that microbial keratitis after LASIK, if treated promptly, does not lead to a permanent reduction in visual acuity. ( info) |
4/763. Delayed onset keratectasia following laser in situ keratomileusis. We present a case of unilateral iatrogenic keratectasia developing 10 months after bilateral laser in situ keratomileusis (LASIK) involving enhancement surgery using a broad-beam excimer laser (Summit Apex) to treat 6.6 diopters (D) of myopia. The ectasia progressed rapidly over the subsequent 12 months. The surgeon did not measure preoperative pachymetry, but preoperative topography and corneal measurements did not reveal underlying keratoconus or forme fruste keratoconus. corneal transplantation was required for final visual rehabilitation. light microscopy of the button revealed no underlying inflammation, which suggests biomechanical corneal weakening as the cause of the ectasia. Scanning electron microscopy showed the dramatic thinning seen clinically. latrogenic keratectasia appears to be a possible complication of LASIK. ( info) |
5/763. Lens opacity after neodymium: YAG laser iridectomy for phakic intraocular lens implantation. We describe a previously unreported complication of a posterior chamber intraocular lens (IOL) implanted in a phakic eye. The left eye of a 25-year-old patient with high myopia was treated prophylactically with neodymium: YAG (Nd: YAG) laser iridotomy prior to phakic IOL implantation. Slitlamp examination of the left eye disclosed an opacity of the anterior capsule of the crystalline lens under the iridotomy site. This case demonstrates a complication associated with Nd:YAG iridotomy prior to implantation of a phakic IOL. ( info) |
| BACKGROUND: The Autonomous Technologies LADARVision excimer laser system utilizes an eye tracking mechanism and a small spot for photorefractive keratectomy. methods: One hundred and two eyes of 102 patients were treated for -1.50 to -6.25 D of spherical myopia at the spectacle plane using a 6-mm diameter ablation zone. One year follow-up was available for 93 eyes (91%). RESULTS: Uncorrected visual acuity for eyes treated for distance vision was 20/40 or better in 99% (n = 90), and 20/20 or better in 70% (n = 64) of eyes at 12 months. Spectacle-corrected visual acuity was 20/25 or better in all 92 eyes reported; no eye lost more than 2 lines of spectacle-corrected visual acuity, and only 1 eye (1.0%) experienced a loss of 2 lines (20/12.5 to 20/20) at 1 year. The refractive result was within /- 0.50 D of the desired correction in 75% (n = 70), and within /- 1.00 D in 93% (n = 86) of eyes at 12 months. Refractive stability was achieved between 3 and 6 months. Corneal haze was graded as trace or less in 100% of the 93 eyes. No significant reductions were noted in contrast sensitivity or endothelial cell density. CONCLUSIONS: patients treated with the Autonomous Technologies LADARVision excimer laser system for -1.50 to -6.25 D of spherical myopia with 1 year follow-up had uncorrected visual acuity of 20/20 or better in 70%, no significant loss of spectacle-corrected visual acuity, no reduction of endothelial cell density or contrast sensitivity, and low levels of corneal haze. ( info) |
| Corectopia, the eccentric displacement of the pupil, may be associated with other abnormalities such as axial high myopia or ectopia lentis. We report the case of a patient presenting for surgery to correct bilateral myopia of 6.50 diopters (D) associated with corectopia. Excimer laser ablation was decentered and performed on the center of the abnormal pupils. After a 2 year follow-up, best corrected visual acuity was 20/20 with -1.00 D correction in each eye. To our knowledge, this is the first report of excimer laser photorefractive keratectomy for myopia associated with corectopia. The satisfactory results suggest that in abnormally eccentric pupils, excimer laser treatment of myopia may be successful when it is centered on the deviated pupil. ( info) |
| We present the histology of a cornea of a woman who had excimer laser photorefractive keratectomy (PRK) for myopia 6 months before she died in an accident. Preoperative spherical refraction was -6.00 diopters (D) with an astigmatism of -0.50 D. Six months postoperatively, refraction was -4.50 D. Slight corneal haze was noted at 1 and 3 months. The corneal histology showed marked epithelial hyperplasia in the center of the ablation zone without subepithelial deposition of newly synthesized collagen, proteoglycans, or both. The epithelial thickness was 38 microns in the untreated area and 93 microns in the center of the ablation. In conclusion, postoperative epithelial hyperplasia was responsible for regression after PRK in this eye. ( info) |
9/763. Hyperoxic myopia in a closed-circuit mixed-gas scuba diver. A myopic shift occurred in a closed-circuit mixed-gas scuba diver using a 1.3 atm abs constant partial pressure of oxygen in a nitrogen-oxygen mix. This change was noticed after approximately 18 days of diving with a mean dive time of 4.04 h each day. The observed myopic shift was due to hyperoxic myopia, one sign of lenticular oxygen toxicity, and resolved over a 1 mo. period after diving was completed. On a subsequent drive trip, a myopic shift was found in both the index diver as well as two other divers breathing the same gasmix on similar profiles. diving communities should be aware of the risk of both lenticular and pulmonary oxygen toxicity when conducting intensive diving at oxygen partial pressures in the 1.3-1.6 atm abs range. ( info) |
10/763. fluorescein test for the detection of striae in the corneal flap after laser in situ keratomileusis. PURPOSE: To report a technique for detecting striae in the corneal flap after laser in situ keratomileusis. methods: fluorescein dye was instilled in the eye, and the patient was asked to blink. The tear film was examined at the slit lamp with the cobalt filter 1 or 2 seconds after blinking. RESULTS: The uneven pattern of pooling in the tear film was a sensitive indicator of the presence of striae in the flap. CONCLUSION: This technique may be useful in detecting minimal striae in the corneal flap in patients with unexplained suboptimal visual acuity after laser in situ keratomileusis. ( info) |