1/336. 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.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
2/336. 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.- - - - - - - - - - ranking = 2keywords = visual (Clic here for more details about this article) |
3/336. 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.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
4/336. photorefractive keratectomy with a small spot laser and tracker.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.- - - - - - - - - - ranking = 5.0699907367738keywords = visual, sensitivity, contrast (Clic here for more details about this article) |
5/336. Excimer laser photorefractive keratectomy in myopic eyes with corectopia.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.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
6/336. 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.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
7/336. culture-negative ulcerative keratitis after laser in situ keratomileusis.A 40-year old man, highly myopic in both eyes, had laser in situ keratomileusis (LASIK) in the left eye in November 1996. Corneal melting and ulceration and fine striae-like interface infiltrates were noticed 1 day postoperatively. There was no response to intensive topical antibiotics in the form of hourly ofloxacin 3% (Tarivid), and satellite lesions developed on day 4. Corneal scrapings for gram stain and culture were done twice. No bacterial or fungal organisms were identified. Intensive topical fortified vancomycin (50 mg/mL) was added, and the lesions resolved gradually over the ensuing 2 weeks. Eighteen months after LASIK, refraction was -1.50 - 0.75 x 105 in the left eye, and uncorrected visual acuity was 20/70, correctable to 20/25 with spectacles.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
8/336. Surgical removal of subfoveal choroidal neovascular membranes in high myopia.BACKGROUND: A study was carried out to elucidate the anatomical and functional outcome after surgical excision of subfoveal choroidal neovascular membranes in high myopia. methods: Sixty-five patients with high myopia (> or =6 diopters), well-defined subfoveal neovascular membranes on fluorescein angiography and preoperative visual acuity < or =20/100 were selected for surgery. A standardized surgical technique was used in all cases, by a single surgeon. The main outcomes assessed were Snellen visual acuity, surgical retinal pigment epithelium defect and postoperative perfusion of the choriocapillaris. Multifactor analysis of variance and chi-square/Fisher's exact test statistics were used to assess the association between patients' pre- and postoperative characteristics and outcome measures. RESULTS: Follow-up ranged from 6 to 48 months (mean 16 months). Mean postoperative visual acuity (0.18) was significantly better than mean preoperative visual acuity (0.09). visual acuity improved by at least two lines in 29 eyes (45%) and was unchanged in 24 (37%). overall, 43 eyes (66%) had visual acuity of 20/200 or better and 15 (23%), 20/60 or better. Predictive factors with a significant effect on final visual acuity were mean visual acuity, preoperative status of retinal pigment epithelium and postoperative perfusion of the choriocapillaris. Postoperative perfusion was detected in 31 (48%) of the total 65 eyes and in 12 (67%) of the 18 eyes with normal retinal pigment epithelium at baseline. The mean postoperative retinal pigment epithelium defect was 4.6 times larger than the original neovascular membrane. In selected patients, SLO macular scotometry showed areas of retained retinal sensitivity within the atrophic scar. CONCLUSION: The natural history of subfoveal neovascularization in high myopia is rarely visually restorative. By contrast, surgical excision of the membranes is feasible and may restore visual acuity in selected patients. This therapeutic approach merits a formal multicenter clinical trial.- - - - - - - - - - ranking = 9.0349953683869keywords = visual, sensitivity, contrast (Clic here for more details about this article) |
9/336. Bilateral macular hemorrhage after laser in situ keratomileusis.BACKGROUND: This is the first report of a bilateral submacular hemorrhage after LASIK surgery in an extreme myo pic patient. A 31-year-old man underwent bilateral surgery for correction of -16.75 0.75x70 degrees and -16.50 0.50x55 degrees. methods: Case report. RESULTS: One day after surgery the patient's uncorrected visual acuity was in the 20/50 range OU and by 17 days after surgery his visual acuity had declined to 20/200 range. Fundus examination showed multifocal subretinal macular and posterior pole hemorrhages. fluorescein angiography showed some macular lesions compatible with lacquer cracks. CONCLUSIONS: Preoperative and postoperative fundus examination is important to detect this phenomenon. patients should be informed of this rare complication.- - - - - - - - - - ranking = 2keywords = visual (Clic here for more details about this article) |
10/336. persistent hyperplastic primary vitreous with myopia: a case study.BACKGROUND: persistent hyperplastic primary vitreous (PHPV) is a congenital disorder that manifests a range of ocular anomalies, including leukocoria, microphthalmia, cataract, and a retrolental fibrovascular membrane. In general, the prognosis for visual acuity with PHPV has been poor. A recent report on six patients who have myopia associated with PHPV showed that these patients were not microphthalmic, did not manifest leukocoria, and showed a mean visual acuity at final followup of 20/160. CASE REPORT: The case of a 3-year-old boy with myopic PHPV of the left eye is presented. Full-time wear of the cycloplegic refraction, combined with patching of the non-amblyopic eye, resulted in an improvement in visual acuity. RESULTS: PHPV with myopia may constitute a distinct subtype of PHPV. patients with myopic PHPV tend to seek treatment later than patients with anterior or posterior PHPV as a result of the lack of microphthalmia and leukocoria. These individuals do not show the long-term complications, such as secondary glaucoma and intraocular hemorrhages, associated with PHPV. CONCLUSION: The acuity improvement in this case of myopic PHPV suggests that a more conservative approach to its surgical management may be appropriate while pursuing refractive correction and amblyopia therapy to attain the best acuity possible.- - - - - - - - - - ranking = 3keywords = visual (Clic here for more details about this article) |
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