Laser in situ keratomileusis for correction of high astigmatism after penetrating keratoplasty

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) for correction of high astigmatism after penetrating keratoplasty, and to assess the refractive results and predictability of the procedure. METHODS: LASIK was performed on 19 patients (19 eyes) with high astigmatism after penetrating keratoplasty, using the Chiron Automated Corneal Shaper and the Chiron-Technolas Keracor 116 excimer laser. The amount of preoperative refractive astigmatism ranged from 6.50 to 14.50 D (mean, 9.21 +/- 1.95 D) and the spherical component of manifest refraction ranged from -7.00 to +1.25 D (mean, -2.14 +/- 2.11 D). All patients completed a minimum follow-up of 12 months. RESULTS: Refraction was stable after 3 months. At 1 year after LASIK, the amount of refractive astigmatism was reduced to a mean of 1.09 +/- 0.33 D (range, 0.50 to 1.75 D), with 57.9% of the eyes within +/- 1.00 D of refractive astigmatism. The mean percent reduction of astigmatism was 87.9 +/- 3.7%. The postoperative spherical component of manifest refraction ranged from -1.00 to +1.75 D with a mean of +0.43 +/- 0.82 D. Vector analysis showed that the mean amount of axis deviation was 1.1 +/- 1.3 degrees and the mean percent correction of preoperative astigmatism was 92.6 +/- 8.4%. There were no intraoperative complications. Spectacle-corrected visual acuity was not reduced in any eye, and improved by 2 or more lines in 42.1% of eyes after LASIK. CONCLUSION: LASIK with the Chiron-Technolas Keracor 116 excimer laser was effective for correction of both astigmatism and myopia after penetrating keratoplasty. The procedure proved to be safe and gave fairly predictable and stable refractive results.     

Mycobacterium interface keratitis after laser in situ keratomileusis

PURPOSE: To report the clinical course, management, and outcome of infectious interface keratitis caused by mycobacterium species after laser in situ keratomileusis (LASIK). DESIGN: A small noncomparative interventional case series. PARTICIPANTS: Five eyes in four patients who underwent LASIK in different locations around the world and had culture-positive mycobacterium keratitis develop. INTERVENTION: The LASIK flap was lifted or amputated, samples were submitted for Ziehl-Neelsen acid-fast stain and Lowenstein-Jensen's agar cultures for diagnosis; topical treatment with fortified clarithromycin and amikacin was administered until clinical resolution. MAIN OUTCOME MEASURES: Time periods from onset to diagnosis and from diagnosis to clinical resolution, and the final visual acuity. RESULTS: Onset of symptoms of infection occurred after a mean of 20 days (range, 11 days-6 weeks) after LASIK or an enhancement procedure. Definitive diagnosis was obtained after a mean period of 4.5 weeks (range, 12 days-8 weeks) from onset. Keratitis resolved within 8.4 weeks (range, 1-18 weeks) of treatment with fortified clarithromycin and amikacin. Corticosteroids were found to worsen and prolong the course of disease. In four of five eyes the LASIK flap was amputated. CONCLUSIONS: Mycobacterial keratitis is a potentially vision-threatening complication after LASIK, characterized by a long latent period, delayed diagnosis, and a protracted course even under intensive specific antibiotic therapy. Inclusion of specific culture media and staining protocols for mycobacteria, along with aggressive treatment on diagnosis, including lifting or amputating the LASIK flap, culturing, topical fortified clarithromycin and amikacin, while avoiding corticosteroids, may significantly improve resolution of the infection and potentially improve the visual outcome.     

Nonmechanical excimer laser penetrating keratoplasty for perforated or predescemetal corneal ulcers

OBJECTIVE: To review the authors' results using nonmechanical excimer laser trephination in penetrating keratoplasty for perforated or predescemetal corneal ulcers. DESIGN: Noncomparative, consecutive, interventional case series. PARTICIPANTS: Thirty-two patients with perforated (17) or deep (15) corneal ulcers (9 bacterial, 5 acanthamoebal, 10 herpetic, 3 associated with rheumatoid arthritis, 5 other) necessitating immediate tectonic keratoplasty. INTERVENTION: Penetrating tectonic keratoplasty with excimer laser trephination was performed along metal aperture masks in donor and recipient corneas. MAIN OUTCOME MEASURES: Clinical results including intraoperative and postoperative complications were evaluated. RESULTS: Trephination was possible in all eyes without perforation of predescemetal ulcers or extrusion of intraocular contents. No eyes with bacterial or acanthamoebal ulcers showed persistence or recurrence of infection. One eye showed recurrent epithelial herpetic keratitis. Best-corrected postoperative visual acuity ranged from 20/700 to 20/20 (median, 20/58), with 30 of 32 eyes achieving improvement of best visual acuity during follow-up (mean, 22.4 months) and with 12 of 32 eyes reaching a visual acuity of 20/40 or greater. Eyes with bacterial or acanthamoebal ulcers showed best results. Episodes of graft rejection occurred in nine eyes and resulted in irreversible opacity of the graft in seven cases. None of the eyes lost all vision, developed endophthalmitis, or had to be enucleated. CONCLUSIONS: Nonmechanical trephination is a useful technical refinement of tectonic penetrating keratoplasty à chaud for perforated or deep progressive corneal ulcers. This technique greatly facilitates exact trephination under these difficult surgical conditions and might possibly improve the prognosis of this procedure.     

Treatment of myopia and myopic astigmatism by customized laser in situ keratomileusis based on corneal topography

OBJECTIVE: To evaluate the predictability, efficacy, and safety of customized laser in situ keratomileusis (LASIK) based on corneal topography in myopia and myopic astigmatism. DESIGN: Prospective, noncomparative interventional case series. PARTICIPANTS: One hundred fourteen patients (eyes) with myopia of -1 to -6 diopters (D) and astigmatism of 0 to -4 D (low myopia group), and 89 patients (eyes) with myopia of -6.10 to -12.00 D and astigmatism of 0 to -4.00 D (high myopia group). INTERVENTION: LASIK was performed with the Hansatome Microkeratome and the Keracor 217 spot-scanning excimer laser (Bausch & Lomb Surgical Technolas, Munich, Germany). Individual ablation patterns were calculated on the basis of elevation data obtained with the Orbscan II corneal topography system (Bausch & Lomb Surgical, Irvine, CA). MAIN OUTCOME MEASURES: Manifest spectacle refraction, visual acuity, and change in visual acuity at 3 months after surgery. RESULTS: At 3 months, 51 patients in the low myopia group and 40 patients in the high myopia group were available. In the low (high) myopia group, 96.1% (75.0%) were within +/-0.50 D of emmetropia, and uncorrected visual acuity was 20/20 or better in 82.4% (62.5%), 20/25 or better in 98.0% (70.0%), and 20/40 or better in 100% (95.0%). A loss of two or more lines of spectacle-corrected visual acuity occurred in 3.9% of the low and 5. 0% of the high myopia group. In low myopia, spectacle-corrected visual acuity was 20/12.5 or better in 5.9% preoperatively and in 13.7% at 3 months and 20/15 or better in 37.3% and 47.1%, respectively. Differences were statistically significant. CONCLUSIONS: The customized LASIK based on corneal topography used in this study showed high predictability and efficacy in myopia and myopic astigmatism of -1.00 to -6.00 D, and could possibly improve spectacle-corrected visual acuity in myopia of -1.00 to -6.00 D. Predictability and efficacy were somewhat lower in myopia and myopic astigmatism of -6.10 to -12.00 D. In both groups, a small number of patients lost two or more lines of spectacle-corrected visual acuity.     

Laser in situ keratomileusis to correct myopia, hypermetropia and astigmatism after penetrating keratoplasty for keratoconus: a series of 27 cases.

BACKGROUND: Excimer laser treatment has been shown to be effective and safe in correcting anisometropia following penetrating keratoplasty (PKP). In this report we review our experience with excimer laser in situ keratomileusis (LASIK) to correct refractive myopia, hypermetropia and astigmatism in patients who had undergone PKP for keratoconus. METHODS: We reviewed the records of 22 patients (27 eyes) who had undergone LASIK to correct myopia, hypermetropia or astigmatism, in simple or combined forms, following corneal transplantation for keratoconus. LASIK was performed at a hospital in Curitiba, Brazil, between September 1998 and February 2000. The eyes were classified into two groups: those with a negative spherical equivalent and those with a positive spherical equivalent. LASIK was performed using the Moria LSK microkeratome and the Nidek EC-5000 excimer laser. RESULTS: The mean length of follow-up was 9.52 months for the 23 eyes with myopia and 5.75 months for the 4 eyes with hypermetropia. The mean refractive spherical equivalent in the myopic eyes was -5.27 (standard deviation [SD] 1.91) dioptres before LASIK and -0.45 D (SD 1.68 D) at the last follow-up visit. The corresponding values in the eyes with hypermetropia were +5.18 D (SD 1.46 D) and + 1.18 D (SD 0.94 D). The rate of regression of astigmatism in the myopic eyes was 76%. After surgery 18 (78%) of the myopic eyes and all the hypermetropic eyes had an uncorrected visual acuity of 20/40 or better. The best spectacle-corrected visual acuity was better than 20/25 in 22 (95.7%) of the myopic eyes and all the hypermetropic eyes. One eye lost 1 line of best spectacle-corrected Snellen visual acuity, and one eye lost 6 lines secondary to epithelial ingrowth. Wound dehiscence, intraoperative flap complications, graft rejection or other complications did not develop in this series. INTERPRETATION: In this series, LASIK proved to be relatively safe and effective in correcting refractive errors after PKP for keratoconus.     

Early results of hyperopic and astigmatic laser in situ keratomileusis in eyes with secondary hyperopia

PURPOSE: To assess the safety and efficacy of laser in situ keratomileusis (LASIK) for secondary hyperopia and hyperopic astigmatism and to develop a VISX STAR S2 LASIK nomogram (VISX Inc., Santa Clara, CA) for consecutive hyperopia after prior myopic refractive surgery. DESIGN: Prospective, nonrandomized, self-controlled interventional study. PARTICIPANTS: Thirty patients with consecutive hyperopia or hyperopia and astigmatism after LASIK, photorefractive keratectomy, automated lamellar keratoplasty, or radial keratotomy. INTERVENTION/METHODS: Prospective evaluation of LASIK in 30 secondary eyes with fogged manifest sphere from +0.5 to +6.0 diopters (D) and cylinder from 0 to +5.0 D. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and spherical equivalent (SE). RESULTS: Mean manifest SE was +1.73 +/- 0.79 D before surgery, -0.13 +/- 1.00 D at 6 months after surgery, and -0.18 +/- 1.08 D at 1 year after surgery. At 6 months, 84% of patients with secondary hyperopia had UCVA of 20/40 or better; 76% were within +/-1 D of emmetropia. At 1 year, 85% had UCVA of 20/40 or better and 85% were within +/-1 D of emmetropia. No patients with secondary hyperopia lost 2 or more lines of BCVA at 1 year. Complications included intraoperative bleeding (3.3%), intraoperative epithelial defect (3.3%), transient interface debris (3.3%), significant dry eye (3.3%), blood in interface (3.3%), irregular astigmatism (6.7%), slight decentration (6.7%), trace haze (6.7%), or mild epithelial ingrowth not requiring removal (3.3%). CONCLUSIONS: These early data suggest that LASIK for consecutive hyperopia from +0.5 to +5.50 D and astigmatism from 0 to +2.75 D using the VISX STAR S2 benefits from a nomogram adjusted for preoperative refraction, age, and prior refractive surgery, and is safe and effective.     

Transscleral contact krypton laser cyclophotocoagulation for treatment of glaucoma in children and young adults

PURPOSE: To evaluate the usefulness of the krypton laser for transscleral contact cyclophotocoagulation (CPC) in the treatment of glaucoma in young patients. DESIGN: Retrospective noncomparative interventional case series. PARTICIPANTS: Transscleral contact krypton laser CPC was performed in 27 glaucomatous eyes of 22 young patients (mean age, 10.5 +/- 5.6 years; range, 11 months-19.4 years). METHODS: The treatment was delivered by means of a fiberoptic probe with compression of the sclera by the probe. The power used was 300 to 500 W per application at the tip of the probe with an exposure time of 10 seconds. MAIN OUTCOME MEASURES: The primary outcome measure is a change in intraocular pressure (IOP). RESULTS: Of the patients who received CPC in both eyes, one eye was randomly chosen for statistical analysis. The mean overall follow-up time was 43.3 +/- 25.3 (median, 36.5; range, 1-82) months after the initial CPC. Preoperatively, the mean intraocular pressure was 35.0 +/- 7.9 mmHg (n = 22). After one or more CPCs, the mean IOP was decreased to 21.5 +/- 8.7 mmHg (n = 22) at 1 month (P < 0.001), to 23.4 +/- 8.6 mmHg (n = 18) at 3 months (P < 0.001), to 25.0 +/- 12.1 mmHg (n = 19) at 6 months (P < 0.01), to 22.1 +/- 9.1 mmHg (n = 16) at 1 year (P < 0.01), and to 22.6 +/- 10.3 (n = 11) at 2 years (P < 0.01). After one or more krypton CPCs, but no other glaucoma procedures, an IOP level of 8 to 21 mmHg or a decrease in IOP of more than 30% was obtained in 14 of 22 (64%) eyes at the last follow-up. No permanent hypotonia, phthisis bulbi, or devastating CPC-related complications were noted. CONCLUSIONS: Krypton laser CPC is a well-tolerated means of lowering IOP in young patients with glaucoma, but repeated treatments may be needed.     

Circumscribed choroidal hemangioma : Clinical manifestations and factors predictive of visual outcome in 200 consecutive cases

PURPOSE: To review the clinical features and management of circumscribed choroidal hemangioma and determine factors predictive of poor visual outcome. DESIGN: Retrospective consecutive noncomparative interventional case series. PARTICIPANTS: Two hundred consecutive patients with circumscribed choroidal hemangioma. MAIN OUTCOME MEASURES: The main outcome measures were analyzed in 155 patients with follow-up of at least 3 months and included complete resolution of subretinal fluid, worsening of visual acuity (more than 2 Snellen lines), and poor final visual acuity (20/200 or worse). RESULTS: The patients were seen at a mean age of 45 years with symptoms of decreased visual acuity (81%), visual field defect (7%), metamorphopsia (3%), floaters (2%), progressive hypermetropia (1%), photopsia (1%), pain (1%), and no symptoms (6%). The referring diagnoses were choroidal hemangioma (29%), choroidal melanoma (29%), choroidal metastasis (9%), retinal detachment (6%), central serous chorioretinopathy (5%), and others. The tumor had a median base of 6.0 mm and median thickness of 3.0 mm. Secondary retinal detachment in the foveal region was present in 81% of the patients. Initial treatment included observation (51%), laser photocoagulation (44%), plaque radiotherapy (4%), external beam radiotherapy (1%), surgical repair of retinal detachment (1%), and enucleation for painful neovascular glaucoma (1%). Kaplan-Meier estimates revealed complete resolution of subretinal fluid in 60% patients at 5 years and 76% patients at 10 years follow-up. By multivariable analysis, clinical factors predictive of complete resolution of subretinal fluid included shorter duration of symptoms (P = 0.03) and inferior quadrant location of tumor (P = 0.001). At initial presentation, 82 of 155 (53%) patients had poor visual acuity (20/200 or worse), and 73 of 155 (47%) patients had good to moderate visual acuity (20/100 or better). Of those 82 patients with poor initial vision, poor final vision was found in 54% at 5 years and 80% at 10 years. Of the 73 patients with good to moderate initial vision, poor final vision was found in 12% at 5 years and 43% at 10 years. By multivariable analysis, clinical factors predictive of poor final visual acuity included poor initial visual acuity (P < 0.001), failure of previous laser photocoagulation before referral (P = 0.01), and tumor management with observation after referral (P = 0.02). Worsening of visual acuity (by more than 2 Snellen lines) was observed in 8% at 5 years and 28% at 10 years of those 82 patients who were initially seen with poor vision. Worsening of visual acuity was found in 10% at 5 years and 30% at 10 years of those 73 patients who initially were seen with good to moderate vision. CONCLUSIONS: Circumscribed choroidal hemangioma is a rare intraocular tumor. In 38% of cases, this tumor is initially misinterpreted before referral as choroidal melanoma or metastasis. Visual acuity is poor in more than 60% of patients at 10 years, despite successful control of associated subretinal fluid in 76% patients.     

Experimental increase in accommodative potential after neodymium: yttrium-aluminum-garnet laser photodisruption of paired cadaver lenses.

PURPOSE: Loss of lens elasticity is one of several proposed mechanisms responsible for the decline in accommodation with age and is the most accepted explanation for presbyopia. We wish to confirm the lens elasticity premise and attempt to experimentally reverse the age-dependent loss of accommodative potential as measured by polar strain. DESIGN: Experimental human autopsy eye study. PARTICIPANTS AND CONTROLS: Thirty-six cadaver lenses were tested to determine the age-dependent polar strain. Eleven lens pairs were then tested with one lens treated with neodymium:yttrium-aluminum-garnet (Nd:YAG) laser and the other left untreated before rotation as an age control. TESTING: Using a custom-made rotational apparatus (described by Fisher, 1971), freshly excised cadaver lenses (<48 hours postmortem) were rotated at 1000 rpm on a 9-mm diameter pedestal to simulate the physiologic pull of the zonules. Lenses were initially tested to determine the age-dependent polar strain. One lens in a pair was then treated with an Nd:YAG laser and the other left untreated before testing. Treatment consisted of 100 suprathreshold pulse placed in a central annular pattern of 2- to 4-mm diameter. Treatment energies varied from 2.5 to 7.0 mJ/pulse, depending on the relative clarity of the lenses. Polar strain was both microscopically measured and calculated from projected photographs before and after rotation of both lased and unlased lenses. Statistically significant differences were determined by paired t test. MAIN OUTCOME MEASURES: Polar strain (decrease in axial thickness with rotation) of the lens. RESULTS: An age-dependent decrease in polar strain was observed that paralleled the findings of Fisher. Both measured and projected polar strain were greater in the lased than unlased lens, and this difference was highly significant by paired t test (P = 0.001 and P = 0.004, respectively). CONCLUSIONS: Age-dependent loss of lens elasticity (polar strain) can be experimentally reversed (increased) by selective intralenticular photodisruption.     

Aqueous and vitreous penetration of levofloxacin after oral administration

OBJECTIVE: To investigate the penetration of levofloxacin, an optical S-(-)isomer of ofloxacin, into the aqueous and vitreous humor after oral administration. DESIGN: Randomized, clinical trial comparing tissue levels of levofloxacin after one or two doses 12 hours apart. PARTICIPANTS: Forty-five patients undergoing initial vitrectomy between February 1997 and June 1997 at the UIC Eye Center. METHODS: Aqueous, vitreous, and serum samples were obtained and later analyzed from 45 patients after oral administration of 1 500-mg tablet (group 1, 22 patients) or 2 500-mg tablets (group 2, 23 patients) 12 hours apart before surgery. MAIN OUTCOME MEASURES: Aqueous, vitreous, and serum concentrations of levofloxacin (micrograms/milliliter). RESULTS: Group 1 achieved mean aqueous, vitreous, and serum levels of 0.59 +/- 0.48 microg/ml, 0.32 +/- 0.34 microg/ml, and 4.34 +/- 3.59 microg/ml, respectively. Group 2 achieved mean aqueous, vitreous, and serum levels of 1.90 +/- 0.97 microg/ml, 2.39 +/- 0.70 microg/ml, and 8.02 +/- 3.14 microg/ml. CONCLUSIONS: Mean inhibitory aqueous and vitreous MIC90 levels were achieved against a majority of ocular pathogens, including Staphylococcus aureus and Staphylococcus epidermidis, Streptococcus pneumoniae (vitreous), Bacillus cereus (vitreous), Haemophilus influenzae, Moraxella catarrhalis, and most gram-negative aerobic organisms except Pseudomonas aeruginosa after two doses given 12 hours apart. Mean MIC90 levels were obtained in the vitreous for a majority of pathogens responsible for traumatic, postoperative, or bleb-related endophthalmitis.