Ultraviolet radiation at Mediterranean latitudes and protection efficacy of intraocular lenses.

PURPOSE: After determining the mean intensity of ultraviolet radiation to which the human eye is exposed at Mediterranean latitudes, this data is used to evaluate the efficacy of the ultraviolet filters incorporated into various intraocular lenses. METHODS: Ultraviolet radiation measured at Mediterranean latitudes was used as a reference for the theoretical calculation of the amount of radiation to which the human eye is exposed. The spectral transmission curve from 290 to 380 nm was measured for 10 IOLs using a UV/VIS Perkins-Elmer Lambda 800 spectrometer. RESULTS: At Mediterranean latitudes, at sea level, with a mean annual solar irradiation of 50 j/cm(2), the human eye receives a quantity of UVA and UVB that is lower than the threshold toxic dose for the rabbit crystalline lens (93 j/cm(2) for UVA and 6.45 j/cm(2) for UVB). However, at higher altitudes and with albedo approaching 0.9 (fresh snow), the amount of radiation increases, with duration of exposure potentially playing a significant role. The UV filters incorporated into the IOLs studied are, in general, protective against such levels of radiation. CONCLUSION: At Mediterranean latitudes, at sea level, the amount of UV radiation to which our eyes are exposed is insufficient to damage the crystalline lens; however, at higher altitudes, the risk of such damage exists. UV filters incorporated into intraocular lenses are generally effective, since they filter all radiation with wavelengths under 380 nm.

Optic nerve alterations in P27(Kip1) knockout mice.

PURPOSE: To study the morphologic characteristics of the optic nerve (ON) by using an experimental model of knockout mice for the expression of the P27(Kip1) gene, mainly involved in cell cycle arrest, apoptosis control, and retinoblastoma protein phosphorylation. METHODS: Eyeballs with the retrobulbar ON attached were obtained from 26-week-old mice. By using morphologic and morphometric techniques, light and electron transmission microscopy, the ON characteristics were determined in two groups of mice: 1) wild type mice as the control group (n=15), 2) homozygous knockout mice (-/-) for the P27(Kip1) gene as the knockout group (n=15). Glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) were studied using Western blot and immunoblotting approaches. RESULTS: The ON cross-sectional area was significantly larger in the P27(Kip1) knockout mice group than in the control group (p<0.001). The axon sizes in knockout animals were much larger than in wild-type mice (p<0.001). Higher number of axons forming the ON, intra-axonal degeneration, myelin sheath, and axoplasm density alterations were found in P27(Kip1) knockout mice when compared with control group (p<0.001). Analysis of lysates of optic nerves by Western blot showed less expression of myelin basic protein and GFAP in P27(Kip1) knockout mice as compared to wild type mice (p<0.005, p<0.01, respectively). CONCLUSIONS: The morphologic and morphometric results suggest that homozygous P27(Kip1) knock-out mice had hypertrophic, hyperplastic, and dystrophic ON.

Optic nerve alterations in PTEN +/- mice.

PURPOSE: To study the morphologic characteristics of the optic nerve (ON) by using an experimental model of knockout mice for the expression of the PTEN gene, mainly involved in cell cycle arrest, apoptosis control, and cell size regulation. METHODS: The eyeballs with the retrobulbar ON attached were obtained from 26-week-old mice. By using morphologic and morphometric techniques, light and electron transmission microscopy, the ON characteristics were determined in two groups of mice: 1) 'wild type' mice as the control group (C-G; n=15), 2) heterozygous knockout mice (+/-) for the PTEN gene (PTEN-G; n=15). Glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) were studied using Western blot and immunoblotting approaches. RESULTS: The ON cross-sectional area was significantly higher in the PTEN-G than in the C-G (p<0.001). The axon sizes in mutant animals were much larger than in wild-type mice (p<0.001). No significant differences were noticed between those groups regarding the number of axons forming the ON and the presence of intra-axonal degeneration, myelin sheath alterations, or axoplasm density. No differences were detected in developmental marker protein expression. CONCLUSIONS: The morphologic and morphometric results suggest that heterozygous PTEN knockout mice had hypertrophic ON without ultrastructural alterations.

Implantation of iris devices in congenital and traumatic aniridias: surgery solutions and complications.

PURPOSE: To show surgical solutions in patients with traumatic and congenital aniridia, to evaluate the clinical improvement of these patients when iris prosthesis are implanted, and to examine safety and complications of these implants in a long-term follow-up. METHODS: Eight patients were included in this retrospective noncomparative case series. Nine eyes had an artificial iris implantation for traumatic or congenital aniridia. Three eyes received a black diaphragm intraocular lens (IOL) in capsular bag after phacoemulsification. An aniridia prosthesis, sulcus sutured, in front of a previous IOL was implanted in two eyes. A black diaphragm IOL, sulcus sutured, in two eyes; two iris diaphragm rings, in front of the previous IOL, in one eye; and a sector iris prosthesis in front of an IOL in the last eye were implanted. Mean follow-up was 22.5 months (range 16 to 44 months). RESULTS: All patients had improved visual acuity (VA) and visual comfort after surgery. The glare disability was subjectively better in all cases. Two patients developed new ocular hypertension after surgery; one of them was controlled by medical treatment and the other needed cyclodiode. Two of the patients with glaucoma preoperatively also needed cyclodiode procedure and one of them an Ahmed valve. CONCLUSIONS: Several kinds of artificial iris implants are available. In all our patients with aniridia, iris artificial prostheses improved VA and diminished visual discomfort. Glaucoma is the most important complication after artificial iris implant. It is possible to implant the iris prosthesis in the capsular bag, but this requires a large capsulorrhexis and presents a surgical challenge.

Effect of prophylactic brimonidine on bleeding complications after cataract surgery.

PURPOSE: To evaluate the effect of prophylactic brimonidine on bleeding complications after cataract surgery. METHODS: The authors performed a prospective, double-masked, two-surgeon study of 137 patients (137 eyes) who underwent phacoemulsification and intraocular lens implantation with or without prophylactic brimonidine before cataract surgery. The authors also compared the effect of brimonidine among patients with systemic diseases such as diabetes mellitus (types I and II), hypertension, and anticoagulant or antiplatelet treatment. RESULTS: Subconjunctival hemorrhage was observed in 73.70% of the patients not treated with brimonidine before surgery and in only 23.75% of the patients who were given prophylactic brimonidine (p<0.001, chi2). The grade of hemorrhage was also statistically significant (p<0.001, Mann-Whitney). No statistically significant difference with regard to the presence of hemorrhage in diabetic patients or in the anticoagulant or antiplatelet treatment group was observed. However, a statistically significant difference (p<0.027, chi2) was found between hypertensive patients treated and not treated with prophylactic brimonidine before cataract surgery. CONCLUSIONS: This study suggests that brimonidine administered before cataract surgery may significantly reduce subconjunctival hemorrhage in the general population. It has been shown to be beneficial in hypertensive patients. A strong statistical trend, but not significance has been found in diabetic patients or in patients treated with antiplatelet or anticoagulant drugs, but further studies are needed to reach conclusive results.

Macular phototrauma after cataract extraction and multifocal lens implantation: case report.

PURPOSE: To report a patient who developed photic injury after cataract surgery and multifocal MF4 lens implantation METHODS: A 41-year-old caucasian woman without antecedents of interest was subjected to left catarct surgery involving phacoemulsification with capsular sac implantation of a new type of multifocal lens. A coaxial light microscope was used for surgery. The operation was filmed and anterior pole photographs were obtained. RESULTS: Two days after the operation, the patient noted a paracentral scotoma and hand movement visual acuity in the left eye. Indirect ophthalmoscopy revealed an oval, hyperpigmented macular lesion compatible with phototoxic maculopathy. CONCLUSIONS: Phototoxic injury to the macula may occur after cataract extraction. Implantation of an intraocular lens is an important factor in the producion of maculopathy, on account of its light-focusing effect on the retina. This effect was probably increased in our patient by the use of a new autofocus multifocal lens.

Posterior chamber phakic intraocular lenses to correct high myopia: a comparative study between Staar and Adatomed models.

PURPOSE: To determine the feasibility of using posterior chamber phakic intraocular lenses (PIOLs) to treat high myopia, comparing two different models, Staar and Adatomed. METHODS: Twenty-four eyes from 12 patients were studied prospectively. A phakic Staar IOL was implanted in one eye of each patient, and the other eye received a phakic Adatomed IOL. Patients with uveitis or ocular trauma prior to ocular surgery, diabetic retinopathy, or capsular pseudoexfoliation were excluded. The mean preoperative spherical equivalent refraction was -16.00 +/- 5.05 D for the Staar group and -15.39 +/- 2.83 D for the Adatomed group. Average follow-up was 32.4 months (range, 19 to 46 mo) for the Adatomed group and 18.3 months (range, 11 to 21 mo) for the Staar group and included evaluation of intraocular pressure, intraocular lens pigment deposits, lens decentration, anterior subcapsular cataract, and visual acuity. RESULTS: Spectacle-corrected and uncorrected visual acuity improved in all eyes in both groups. No statistically significant differences in visual acuity gain were observed with the two materials (Student t-test, P = .08 for the Staar group and P = .6 for the Adatomed group), although the gain in visual acuity was somewhat greater with the Staar PIOLs. The difference in mean intraocular pressure before surgery and at last follow-up was 1.5 mmHg for the Staar group and 2.3 mmHg for the Adatomed group (P = .36). The incidence of lens pigment deposits was the same in both groups (41.66%), with deposits in 5 of the 12 eyes in both groups. The incidence of lens decentration was higher in the Adatomed group (5/12; 41.66%) than in the Staar group (2/12; 16.7%). Anterior subcapsular cataract was higher in the Adatomed group (4/12; 33.3%) than in the Staar group (3/12; 25%). CONCLUSIONS: There was a higher incidence of lens decentration and anterior subcapsular cataract in the Adatomed group than in the Staar group.

Multicenter study of the Artisan phakic intraocular lens.

PURPOSE: To assess the Artisan intraocular lens to correct myopia in phakic eyes. SETTING: European multicenter study sponsored by Ophtec BV, Groningen, The Netherlands. METHODS: In this prospective multicenter clinical study, the Artisan lens was implanted in 518 eyes between September 1991 and October 1999. The power of the lenses ranged from -5.0 to -20.0 diopters (D). Follow-up examinations were performed at 6 months and 1, 2, and 3 years. Follow-up ranged from 6 months (n = 454) to 3 years (n = 249). The preoperative uncorrected visual acuity (UCVA) was not recorded but was estimated to be worse than 0.1. The preoperative mean best spectacle-corrected visual acuity (BSCVA) was 0.67 +/- 0.26 (SD). Endothelial cell counts were done at 6 months and 1, 2, and 3 years in a subgroup of 129 eyes. RESULTS: A UCVA of 20/40 or better was observed in 76.8% of eyes regardless of the postoperative goal. A BSCVA of 20/40 or better was observed in 93.9% of eyes and remained stable throughout the follow-up. Of the eyes with extremely high myopia (>-15.0 D), 63.3% gained 2 or more lines of BSCVA; of those with moderate myopia (-5.0 to -10.0 D), 23.5% gained 2 or more lines. The mean endothelial cell density change was 4.8% at 6 months, 2.4% at 1 year, 1.7% at 2 years, and 0.7% at 3 years. The incidence of persistent adverse events at 3 years was relatively low. Secondary surgical interventions included repositioning of the lens because of poor initial placement and lens exchange because of preoperative power calculation errors. Glare and halo effects during night driving were noted and were related to large pupils in young patients. CONCLUSION: The Artisan lens is a safe, stable, efficacious, and predictable method to correct -5.0 to -20.0 D of myopia. This study suggests that the corneal endothelial cell loss is stabilized to the physiologically normal level after 3 years.

Acute iridocyclitis in a patient with AIDS diagnosed as toxoplasmosis by PCR.

PURPOSE: To study the etiology of an acute iridocyclitis in a patient with AIDS using polymerase chain reaction (PCR) analysis of aqueous humor. METHODS: Case report describing a patient diagnosed with toxoplasmic retinochoroiditis in his left eye. He stopped his treatment after three weeks and subsequently developed an acute iridocyclitis without chorioretinitis in the fellow eye. Anterior chamber paracentesis was performed and aqueous humor was assayed by PCR. RESULTS: PCR of the aqueous humor showed positivity for Toxoplasma gondii. The iridocyclitis responded to topical dexamethasone and oral treatment with pyrimethamine and sulfadiazine. CONCLUSION: PCR is an effective method to diagnose toxoplasmic iridocyclitis in a patient with AIDS.

[Amaurosis fugax as the early manifestation of orbital schwannoma]. / Amaurosis fugax como manifestación precoz de schwanoma orbitario.

PURPOSE/METHODS: We report a case of a 51-year-old woman who clinically presented amaurosis fugax in her left eye of four months' duration. RESULTS/CONCLUSIONS: Computed tomography showed a well defined intraconal mass suggestive of cavernous hemangioma. A left lateral orbitotomy was performed. A red and encapsulated mass was removed in its entirety without violation of its capsule. Microscopically, it was composed of areas of spindle-shaped cells disposed in form of palisade (Antoni type A) mixed with cystic areas where the cells were scattered in a loose myxoid matrix (Antoni type B). Some nuclei were large, hyperchromatic, pleomorphic and multilobulated. The diagnosis was made on the basis of the histopathologic findings.

Endothelial study of iris-claw phakic lens: four year follow-up.

PURPOSE: To study quantitative and morphometric endothelial changes in phakic eyes implanted with the Worst iris-claw lens to correct high myopia. SETTING: Department of Ophthalmology, University Hospital "La Fe", Valencia, Spain. MATERIAL AND METHODS: This retrospective study involved 111 phakic eyes (73 patients) implanted with the Worst iris-claw lens. Noncontact specular microscopy and computer-assisted analysis was performed preoperatively and 6 months and 1, 2, 3, and 4 years postoperatively. RESULTS: The mean cell loss was 3.85% at 6 months, 6.59% at 1 year, 9.22% at 2 years, 11.68% at 3 years, and 13.42% at 4 years. At 2 years, the hexagonality and coefficient variation in cell size were close to the preoperative levels. No major complications were seen; early postoperative corneal touch required intraocular lens (IOL) removal in 1 case (0.9%). Four eyes (3.6%) needed a reoperation because of poor IOL fixation (2 eyes), traumatic subluxation of the IOL (1 eye), and miscalculation of the IOL power (1 eye). CONCLUSIONS: Although there was a slight progressive cell loss after IOL implantation, the morphometric changes recovered and were close to the preoperative levels. This suggests that endothelial damage occurred primarily during the surgical procedure.

Endophthalmitis following open-globe injuries.

Endophthalmitis following open-globe injuries is caused by a specific range of microorganisms, of which Bacillus sp. and coagulase-negative Staphylococcus are the most frequent. Risk factors include the presence of an intraocular foreign body, injury inflicted by organic material, delay in surgery, and the type of wound involved. Despite important advances in medical and surgical management, this type of endophthalmitis continues to pose a poor prognosis. In this sense, we consider prevention to be the best approach. We report our protocols for the prevention and treatment of endophthalmitis following open-globe injuries, based on recent experimental studies on the ocular pharmacokinetics of antibiotics and on multicenter studies of the treatment of endophthalmitis.

Iris claw phakic intraocular lens for high myopia.

BACKGROUND: The implantation of a Worst-Fechner iris claw intraocular lens (IOL) is one of the surgical procedures used for the correction of high myopia. This technique reduces myopia with stable refractive results; however, its potential long-term risks have not been evaluated. We report results in 94 eyes with a minimum follow-up of 3 years. METHODS: We studied 94 eyes of 62 patients with myopia > or = -7.00 diopters (D) who underwent Worst-Fechner IOL implantation. Lens decentration, permeability of the blood-aqueous barrier by iris angiography, and changes in corneal endothelial density were analyzed. RESULTS: Mean follow-up time was 48.9 months (range 36 to 72 mo). Three years after surgery, 58 eyes (61%) had an uncorrected visual acuity > or = 20/40, and 77 eyes (82%) gained two or more lines of spectacle-corrected visual acuity with respect to the preoperative value; 75 eyes (79%) were within +/- 1.00 D of emmetropia and 46 eyes (48%) were within +/- 0.50 D of emmetropia. The mean endothelial cell loss was 17.9% at 5 years after surgery, while the percentage of hexagonality and the coefficient of cell variation tended toward preoperative levels. No vision threatening complications were seen. CONCLUSIONS: The implantation of a Worst-Fechner iris claw phakic IOL reduced high myopia with a stable refractive outcome. Endothelial cell damage was within acceptable limits. The absence of major complications makes this procedure an acceptable method for correcting high myopia.

Diclofenac sodium and cyclosporin A inhibit human lens epithelial cell proliferation in culture.

PURPOSE: To investigate the effect of diclofenac sodium salt and cyclosporin A (CsA) on human lens epithelial cell (HLEC) growth in culture. METHODS: Cultures of HLEC were obtained from anterior capsules from extracapsular cataract surgery. Third-passage cells were seeded in 96-well plates in 0.1 ml culture medium. Cytotoxicity was estimated by the tetrazolium test in confluent monolayers after 24 h exposure to a wide range of concentrations of diclofenac and CsA. The effect of subcytotoxic concentrations of diclofenac and CsA on HLEC proliferation in subconfluent cultures was evaluated after 24 and 72 h of exposure. To investigate the relationship between PGE2 synthesis and the inhibitory effect of these drugs, after 24 h of exposure to diclofenac and CsA the production of PGE2 was measured by radioimmunoassay. We also tested the effect of exogenous PGE2 addition to diclofenac 72-h-treated cultures. RESULTS: Diclofenac and CsA (at concentrations > or = 65 microM and > or = 2.5 microM, respectively) inhibited the proliferation of subconfluent cultures of HLEC in a dose-dependent fashion. Diclofenac inhibits PGE2 synthesis, while CsA at high doses stimulates PGE2 synthesis of cultured HLEC. Exogenous PGE2 addition reversed in part the inhibitory effect of diclofenac. CONCLUSIONS: Diclofenac and CsA at appropriate doses are effective in inhibiting cultured HLEC proliferation. This could be of interest to prevent posterior capsule opacification. Further in vivo experimental studies seem worthwhile.

Anterior chamber contamination following uncomplicated cataract surgery: comparative results using intravenous imipenem.

BACKGROUND AND OBJECTIVE: An attempt was made to establish the effect of an intravenous antibiotic on anterior chamber (AC) fluid contamination when administered before surgery. PATIENTS AND METHODS: A prospective study of AC contamination was conducted in 60 patients undergoing extracapsular cataract extraction (ECCE)/intraocular lens (IOL) implantation. The final 20 patients received 1 g of intravenous imipenem 1 hour before surgery. RESULTS: There were 4 positive AC cultures from the 20 patients in the imipenem group, and 13 positive AC cultures from the 40 control patients (P = .4, chi-square test). Of the 60 eyes, 17 had positive AC aspirate cultures and 23 had positive conjunctival smears. Only in one instance was the microorganism isolated from each case the same (1.7%). CONCLUSIONS: An insignificant decrease in AC contamination was observed when intravenous imipenem was used before surgery. The results also suggest that conjunctiva might not be the main source of contamination during surgery.

Endothelial toxicity of ceftazidime in anterior chamber irrigation solution.

Due to the high toxicity of aminoglycoside antibiotics, many authors prefer to use third generation cephalosporines in the prophylaxis and treatment of intraocular infections. The aim of the present study was to determine safe ceftazidime levels in anterior chamber irrigation solution. Twenty-two eyes of 12 white New Zealand rabbits were divided into six groups of two animals each. Double paracentesis was performed in both eyes, irrigating the right eye with 250 ml of BSS-Plus (BSS+) solution, and the left eye with 250 ml of BSS+ solution with increasing concentrations of ceftazidime (2, 3, 4, 6 and 8 mg ml-1). Each rabbit was killed at the end of surgery, except the last group, which received BSS+ and BSS+ with 8 mg ml-1 of ceftazidime, respectively, in one eye, and were then killed 24 hr later. Endothelial lesions were assessed by silver nitrate staining. We considered lesions endothelial silver affinity ranging from minimal (1-2+) to intense (3-4+). 1-2+ silver affinity was found in 4 +/- 1.35% of endothelial cells in the controls; this percentage in turn increased with antibiotic concentration (6.1 +/- 1.13%, 6.7 +/- 0.4%, 7.2 +/- 1.36%, 7.3 +/- 1.93% and 7.5 +/- 1.83%, respectively). The percentage of 3-4+ silver affinity was 0.18 +/- 0.17% in the controls, and likewise increased with antibiotic concentration (0.22 +/- 0.11%, 0.37 +/- 0.09%, 2.8 +/- 0.63% and 3.1 +/- 0.46%, respectively). The increase in affinity was greatest up to the 4 mg ml-1 concentration. In the last group there were zones of endothelial alterations in morphology and size, with signs of attempted repair in the eye treated with antibiotic, but none in the case treated only with BSS+. Ceftazidime concentrations above 3 mg ml-1 in intraocular infusions induce endothelial cell toxicity.

Iris-fixated Worst claw versus sulcus-fixated posterior chamber lenses in the absence of capsular support.

PURPOSE: To evaluate visual outcomes and complications of iris-fixated intraocular lenses (IOLs) (lobster-claw) and sutured sulcus-fixated posterior chamber (PC) IOLs in primary and secondary implantation. SETTING: Eye Department, University Hospital "La Fe", Valencia, Spain. METHODS: This retrospective study reviewed 47 patients who had primary implantation of an iris-fixated (n = 34) or sulcus-fixated (n = 13) IOL and 54 patients who had secondary implantation of an iris-fixated (n = 41) or sulcus-fixated (n = 13) IOL. RESULTS: Visual acuity in the primary implantation group was similar with both lens types. Overall, 54.0% had a postoperative acuity of 20/40 or better. In eyes without pre-existing pathology, 60.0% with an iris-fixated IOL and 54.6% with a sutured PC IOL had this level of postoperative acuity (P = .768). In the secondary implantation group, the percentage of patients with a postoperative visual acuity of 20/40 or better was significantly higher in iris-fixated IOL eyes (78.0%) than in sulcus-fixated PC IOL eyes (46.2%) (P < .05). In eyes without pre-existing pathology, the difference was maintained. No intraoperative complications directly associated with iris-fixated lens implantation occurred. The incidence of postoperative complications common to either IOL type in primary and secondary implantation did not differ significantly. The incidence of retinal complications was higher in eyes that had primary implantation of either lens type, although the differences between both lenses in either primary or secondary implantation were not significant. CONCLUSION: The good visual outcomes and low incidence of intraoperative and postoperative complications in eyes with iris-fixated IOLs indicate that these lenses should be considered an alternative to sutured PC IOLs in eyes in which capsular support is inadequate or absent.

Comparison of intersecting trapezoidal keratotomy and arcuate transverse keratotomy in the correction of high astigmatism.

BACKGROUND: High astigmatism can be corrected using trapezoidal or arcuate transverse keratotomies. Videokeratography enables qualitative evaluation of the corneal topography. METHODS: Fifty-five eyes of 41 patients presenting with high astigmatism after penetrating keratoplasty or naturally occurring astigmatism (mean, 6.29 diopters [D]; range, 3.00 to 16.00 D) underwent correction using either intersecting trapezoidal or arcuate transverse keratotomies. Corneal topographic maps were analyzed and classified into keratographic patterns. Mean follow up was 3 years (range, 1 to 6 years). RESULTS: The mean net decrease in refractive astigmatism was 3.60 D (52.7% reduction). The flattening/steepening ratio was on average higher for intersecting trapezoidal keratotomy (7.26 for astigmatism after penetrating keratoplasty and 8.31 for naturally occurring astigmatism) than for arcuate transverse keratotomy (.98 in astigmatism after penetrating keratoplasty and 1.76 in naturally occurring astigmatism). Accordingly, intersecting trapezoidal keratotomy tended to produce a hyperopic shift in the spherical equivalent refraction (mean hyperopic shift, 2.65 and .56 D, respectively). The mean vector-corrected change of refractive astigmatism after intersecting trapezoidal keratotomy was 88.8% in naturally occurring (n = 21 eyes) and 70.3% in penetrating keratoplasty astigmatism (n = 13). Arcuate transverse incisions corrected on average 79.9% of naturally occurring (n = 13) and 60.8% of penetrating keratoplasty astigmatism (n = 8). Videokeratography showed the asymmetric bowtie pattern as the most frequent pattern for both procedures. Intersecting trapezoidal keratotomy was characterized by relatively higher incidences of polygonal and irregular patterns. Arcuate transverse incisions caused less wound healing defects and glare than intersecting trapezoidal keratotomy. CONCLUSIONS: Both intersecting trapezoidal keratotomy and arcuate transverse incisions effectively reduced high naturally occurring astigmatism and astigmatism after penetrating keratoplasty. However, greater corneal surface irregularity and more complications were seen following intersecting trapezoidal keratotomy. Trapezoidal keratotomy should not be used unless a large decrease of myopia is needed, and then a nonintersecting technique is preferable.