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At least 955 records · Page 53Linked to original sources
PubMed1989

Distribution of axial combinations in astigmatism patients.

A total of 527 astigmatic patients were examined for their axial distribution. The values taken for all eyes together confirmed the preponderance of "+" cylinder at an axis of 90 degrees. However, only a small percentage of patients demonstrated a 90 degree axis for each eye separately. Mirroring and parallel axes were more common and an asymmetric axial distribution was found most frequently. The influence of lid pressure on the development of astigmatism thus seems, according to our findings, unlikely. Genetic factors are more probable.

Astigmatism↗
PubMed2003

[Laser in situ keratomileusis for correction of hyperopia and hyperopic astigmatism using a scanning spot excimer laser. Results of a prospective clinical study after 1 year].

PURPOSE: The purpose of this investigation was to evaluate the safety, efficacy, predictability, stability and complications of LASIK for the treatment of hyperopia and hyperopic astigmatism using a scanning spot excimer laser. PATIENTS AND METHODS: A total of 64 consecutive LASIK operations (37 patients, mean age 41 years, range 22-68 years) have been evaluated. The Hansatome microkeratome producing a superior hinge (flap diameter 9.5 mm) and a scanning spot excimer laser with an optical zone of 6.0 mm were used. Examinations were performed preoperatively, after 1 day, 7 days, 1 month, 4 and 12 months. RESULTS: One year after the primary procedure only 1 eye lost 2 or more lines of best-corrected visual acuity, 91% were within +/-1 line and 4 eyes gained 2 lines. Of these eyes 50 (86%) reached an uncorrected visual acuity of > or=0.5, 32 (55%) > or=0.8, 16 (28%) > or=1.0, 24 eyes (41%) needed a refractive correction of +/-0.5 D, 44 eyes (76%) of +/-1.0 D and 55 eyes (95%) of +/-2.0 D. The mean spherical equivalent after 1 year was +0.17+/-0.85 D. CONCLUSIONS: LASIK is suitable for the correction of hyperopia (up to a maximum of +5 D) and for hyperopic astigmatism (up to a maximum of -5 D). However, results were better in lower hyperopia (up to +3 D) than in the moderate hyperopia. The refractive results showed overall a good stability during the 12-month study period, but higher regression occurred in a few cases.

Adult↗
PubMed2005

[Toric intraocular lenses for correction of persistent corneal astigmatism after penetrating keratoplasty].

PURPOSE: Cataract extraction with implantation of toric intraocular lenses (tIOL) is a new surgical option for correction of residual astigmatism following penetrating keratoplasty and cataract with only minimal direct manipulation of the graft. PATIENTS AND METHODS: We implanted an individually manufactured backtoric tIOL in 11 eyes of 9 patients. TIOL power calculation was done using vergence transformation in a paraxial space. RESULTS: Implantation and intraoperative alignment of tIOL were uneventful in all patients. Uncorrected visual acuity increased from 0.1+/-0.06 preoperatively to 0.47+/-0.18 (p=0.006) postoperatively. Best-corrected visual acuity changed from 0.23+/-0.18 preoperatively to 0.6+/-0.14 postoperatively (p=0.002). The refractive cylinder could be reduced from 7.0+/-2.6 D to 1.63+/-1.5 D (p=0.001) after surgery. We observed a small mean deviation from the target axis of 4.1+/-2.9 degrees (0-8 degrees ) after a mean follow-up time of 3.5 (2-7) months. CONCLUSION: TIOL implantation is a promising option for correction of high astigmatism following penetrating keratoplasty with only minimal direct surgical manipulation of the graft. Regular and symmetric corneal topography is essential for successful implantation of tIOL.

Aged↗
PubMed1998

[Laser in situ keratomileusis (LASIK) for correction of myopia and astigmatism].

PATIENTS AND METHODS: In order to better define the potential advantages and risks of laser in situ keratomileusis (LASIK), we designed a prospective study including 73 eyes. RESULTS: After 6 months, 62 eyes were examined. Myopia was corrected from -6.10 +/- 3.12 (mean +/- standard deviation) to +0.04 +/- 0.66 D, with 54 eyes (87.1%) being within +/- 1.00 D of emmetropia. Astigmatism was corrected from -1.07 +/- 1.02 to -0.32 +/- 0.89 D. Uncorrected visual acuity was 0.5 or better in 59 eyes (95.2%) and 1.0 or better in 27 eyes (43.5%) 6 months postoperatively. More than one line in best-corrected visual acuity was lost by 6 eyes (9.7%), with most of these eyes being highly myopic. There was no change or a gain in lines in best corrected visual acuity in 42 eyes (66.1%). Intraoperative complications arose in two eyes (2.7%); in one eye, visual acuity was temporarily decreased. More treatments were performed in 7 eyes (9.6%). Postoperatively, no haze, scars or central islands were detected. Patient satisfaction after LASIK was high: 97.3% were pleased or very pleased with the result. CONCLUSIONS: In conclusion, LASIK is effective in the correction of myopia and myopic astigmatism. Although complications more frequently occurred in the correction of higher refractive errors, LASIK seems to be relatively safe compared with other refractive methods.

Adult↗
PubMed2001

[LASIK with a superior hinge and scanning spot excimer laser ablation for correction of myopia and myopic astigmatism. Results of a prospective study on 100 eyes with a 1-year follow-up].

PURPOSE: Recently laser-in-situ-keratomileusis (LASIK) has been increasingly used to correct refractive errors. The purpose of this investigation was to evaluate the safety, efficacy, predictability, stability and complications using the scanning spot excimer LASIK technology. PATIENTS AND METHODS: The results of 100 consecutive LASIK operations carried out between 2/1998 and 2/1999 on 60 patients (mean age 37 years, range 20-55 years) have been evaluated. The Hansatome microkeratome with a superior hinge (flap diameter: 9.5 mm) and a scanning spot excimer laser (Technolas C-Lasik 217) were used in all cases. The mean spherical equivalent of the subjective manifest refraction was -6.96 +/- 2.87 diopters (D), the mean sphere was -6.47 +/- 2.71 D and the mean astigmatism was -0.98 +/- 0.94 D. In 6% of the eyes preoperative visual acuity was not better than 20/40. Examinations were performed preoperatively, after 1 and 7 days, after 1,4 and 12 months. Safety, efficacy, predictability, stability and complications were calculated using the datagraph software (version 1.11). RESULTS: All 100 eyes were examined after 1 day and 1 week, 96 after 1 month, 95 after 4 months and 92 after 1 year. Following 1 year none of the eyes lost 2 or more lines of best corrected visual acuity, 99% were within +/- 1 line and 1% gained 2 lines (safety index 1.03). In 92% of all eyes an uncorrected visual acuity of > or = 0.5 was reached, in 77% > or = 0.8 and in 51% > or = 1.0 (efficacy index 0.89). For 60 eyes (65.21%) a refractive correction of +/- 0.5 D was necessary, for 82 eyes (89.13%) +/- 1.0 D and for 91 eyes (98.91%) +/- 2.0 D. The mean spherical equivalent after 1 year was -0.15 +/- 1.31 D. Between 1 and 12 months a mean regression of -0.14 D occurred. On the request of the patients, 5 eyes were retreated during the study period for under- or over-correction. Complications due to the microkeratome did not occur. Corneal infections were not observed, a diffuse lamellar keratitis (DLK) was seen in 12 cases, but all cases healed with no loss of visual acuity. In 7 eyes a slight decentration of the ablation was observed using corneal topography, which in one case caused an increase in glare sensitivity. CONCLUSIONS: LASIK with superior hinge and scanning spot excimer photoablation is suitable for the correction of myopia (up to a maximum of -12 D) and for myopic astigmatism (up to a maximum of -5 D). The refractive results showed a high stability during the 12-month study period but there is still room for improvement of the predictability.

Adult↗
PubMed1982

Corneal astigmatism from conjunctival cysts.

Two patients had decreasing visual acuity because of corneal astigmatism induced by a conjunctival cyst. In both cases, surgical removal of the cyst resulted in marked improvement because of a reduction in astigmatism. In one case, the cause of decreased visual acuity was unknown for two years; keratometry and a careful examination of the eyelids disclosed the cyst.

Adult↗
PubMed1985

Postoperative astigmatism after central vs eccentric penetrating keratoplasties.

Six patients with markedly eccentric penetrating keratoplasties had severe corneal astigmatism (mean, 10.38 +/- 2.91 diopters). In four of these patients the flat meridian was lying in the direction of graft displacement. Laboratory experiments disclosed no statistically significant difference in diameter between the major and minor axes of the corneal buttons in the centrally and eccentrically trephined eyes and we could not elucidate the mechanism of the severe astigmatism. However, in the eccentrically trephined eyes the longer axis consistently lay in the direction of decentration whereas in the centrally trephined eyes the long axis was oriented randomly.

Astigmatism↗
PubMed1988

Excimer laser keratectomy for correction of astigmatism.

We treated 13 eyes (12 patients) with excimer laser surgery for correction of astigmatism using linear corneal T-excisions. All eyes were followed up for a minimum of three months. We used a newly developed delivery system and special contact masks to deliver the 193-nm excimer light. Astigmatic corrections of up to 4.16 diopters were obtained. The actual corrections corresponded well with the intended values as predicted by a biomechanical theory. The refractive change over time was different than that observed after knife incisions, suggesting different repair mechanisms. An epithelial plug filling the whole T-excision persisted for over one year in all eyes.

Adult↗
PubMedDate not supplied

Postoperative astigmatism.

With the numerous significant advances in surgical methodology--e.g., microinstrumentation, the operating microscope, the surgical keratometer, and intraocular lenses--that have been developed over the past two decades, both surgeons and patients have become increasingly aware of the final optic result of any surgical intervention. This is especially so since the development of refractive surgery, where good uncorrected vision is frequently the final arbiter of success. We have progressed to the stage where the optic manipulation of the cornea, whether intentional or otherwise, can be understood in terms of a number of variables. These include the preparation and closure of the surgical wound, the choice of suture material, and both intraoperative and postoperative manipulations. Where these have failed and postoperative astigmatism still occurs, a number of surgical procedures are available to reduce the astigmatic error to an acceptable level.

Astigmatism↗
PubMed1983

Photorefraction of normal and astigmatic infants during viewing of patterned stimuli.

Photorefraction was used to assess the state of accommodation of 3-month old infants with and without astigmatism while they viewed stimuli in an apparatus commonly used to test infant visual acuity. The stimuli were a 1.6 c/deg vertical grating, a 1.6 c/deg horizontal grating and a cross composed of orthogonal 19 min lines, which were presented 55 cm from the infants. Most infants' accommodation was appropriate for the vertical grating. Astigmatic infants did not change their focus when the orientation of the grating was changed.

Accommodation, Ocular↗
PubMed1983

Non-astigmatic children's contrast sensitivities differ from anisotropic patterns of adults.

Monocular contrast thresholds were estimated for horizontal (H), vertical (V) and left and right diagonal 10 c/deg sinusoidal gratings for non-astigmatic children (4:10--11:2 yr) and adults using yes-no signal detection (YN) methods. Some children were also tested with two-interval forced-choice (2IFC). Younger children were less likely to have the typical adult pattern of anisotropic sensitivity, favoring H and V, while 10--11 yr olds had more adult-like anisotropy. Within all age groups patterns of anisotropy varied considerably. Deviation of adults from the typical pattern may be related to small amounts of astigmatism in their untested eyes. 4- and 5-yr olds were confused by 2IFC. For children 6 yr and older, 2IFC and YN threshold estimates were equivalent, but 2IFC required less testing time.

Adolescent↗
PubMed2006

Severe astigmatic amblyopia secondary to subcutaneous juvenile xanthogranuloma of the eyelid.

A number of eyelid lesions in early childhood, most commonly dacryoceles and hemangiomas, have been documented to cause astigmatic changes of the cornea. Juvenile xanthogranuloma (JXG) is typically reported to include both cutaneous skin and anterior ocular segment lesions. We report a case of a 10-month-old infant in which a subcutaneous JXG lesion of the lower eyelid resulted in visually significant astigmatic amblyopia.

Amblyopia↗
PubMed2004

Surgically induced astigmatism after superotemporal and superonasal clear corneal incisions in phacoemulsification.

PURPOSE: To evaluate surgically induced corneal astigmatism after small superotemporal and superonasal clear corneal incision cataract surgery. SETTING: Department of Ophthalmology, School of Medicine, University of Afyon Kocatepe, Afyon, Turkey. METHODS: This prospective study comprised 56 eyes of 28 patients who had bilateral phacoemulsification and implantation of a foldable intraocular lens (IOL) through a corneal tunnel incision. A superotemporal incision was used in all right eyes, and a superonasal incision was used in all left eyes. Topography was performed preoperatively and at 1 week, 1, 3, and 6 months, and 1 year. Surgically induced astigmatism (SIA) was calculated by vector analyses using the Holladay-Cravy-Koch method. The incision length was measured and was between 3.30 mm and 3.50 mm in all eyes. RESULTS: Although SIA did not differ significantly between the 2 incision groups (P>.05), decomposition of vectors showed that the horizontal component of SIA after superonasal incision was statistically significantly higher than superotemporal incision throughout the study (P<.05). Vertical components of SIA and the incision size after IOL implantation with the syringe/cartridge system between the 2 incision groups were not significantly different (P>.05). CONCLUSION: There was no statistically significant difference in SIA between superotemporal incisions in the right eyes and superonasal incisions in the left eyes 1 year after surgery for a surgeon who sits at the 12 o'clock. Superonasal clear corneal incisions can be used in left eyes and superotemporal clear corneal incisions in right eyes.

Adult↗
PubMed2004

Refractive lensectomy and cross-cylinder laser in situ keratomileusis for the correction of extreme hyperopic astigmatism.

Refractive lensectomy followed by cross-cylinder laser in situ keratomileusis was performed in both eyes of a 46-year-old patient with extreme hyperopic astigmatism. Six months postoperatively, the uncorrected visual acuity was 20/25 with a manifest refraction of +0.25 -0.50 x 44 in the right eye and +0.25 -0.25 x 10 in the left eye. The best corrected visual acuity remained unchanged in both eyes at 20/25. Refractive lensectomy and cross-cylinder LASIK can be effective for treating extreme hyperopic astigmatism.

Astigmatism↗
PubMed2004

Safety, efficacy, and stability indices of LASEK correction in moderate myopia and astigmatism.

PURPOSE: To evaluate the visual outcomes and complications in low to moderate levels of myopia and astigmatism treated with laser-assisted subepithelial keratectomy (LASEK) with a focus on postoperative recovery. SETTING: Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA. METHODS: A retrospective analysis of a case series of eyes treated with LASEK from 1996 to July 2002 with a follow-up of 2 years was performed. The LASEK technique involved creating an epithelial flap with 25 to 45 seconds of exposure to 20% alcohol, ablating the corneal surface using 3 different excimer lasers and nomogram adjustment, and repositioning the flap and applying a bandage contact lens. The main outcome measures were uncorrected visual acuity (UCVA), efficacy index, manifest refraction, best spectacle-corrected visual acuity (BSCVA), safety index, retreatment rate, and complications. RESULTS: One hundred seventy-one eyes (85 right eyes and 86 left eyes) of 105 patients were studied. Preoperatively, the mean spherical equivalent was -2.99 diopters (D) +/- 1.43 (SD) (range -0.38 to -7.75 D) and the mean cylinder, -0.78 +/- 0.73 D. The UCVA ranged from 20/800 to 20/32, and the BSCVA ranged from 20/63 to 20/16; the median was 20/20. One week postoperatively, 96% of eyes had a UCVA of 20/40 or better but definitive visual recovery took more than 4 weeks in some eyes. Approximately 95% of eyes were within +/-1.0 D of emmetropia after 4 to 52 weeks; the remaining 5% did not show major deviations. At 4 to 52 weeks, only 1 eye was overcorrected by more than 1.0 D of manifest refraction. The safety index remained close to 1.0 for the follow-up after 4 weeks. The efficacy index displayed a plateau at 0.9 from 1 month to 1 year. No serious complication (including recurrent erosion syndrome) was encountered. The mean follow-up was 31 weeks, and the retreatment rate was 2.9% up to 2 years of follow-up. CONCLUSIONS: The long-term safety and effectiveness of LASEK for the correction of low to moderate myopia and astigmatism were demonstrated. The treatment effect stabilized after 4 weeks.

Adult↗
PubMed2005

Wavefront-guided laser in situ keratomileusis using the WaveScan system for correction of low to moderate myopia with astigmatism: 6-month results in 277 eyes.

PURPOSE: To assess the safety and effectiveness of wavefront guided LASIK surgery using the Visx WaveScan system for correction of low to moderate myopia with astigmatism. SETTING: Multicenter study at 6 sites in the United States. METHODS: In this prospective nonrandomized clinical trial, treatments were performed at 6 sites in the United States using the WaveScan (CustomVue) guided excimer laser. A total of 351 eyes were enrolled, and 277 eyes were analyzed at 6 months. RESULTS: At 6 months, 94% of eyes achieved an uncorrected visual acuity (UCVA) of 20/20 or better and 74% achieved a UCVA of 20/16 or better. Sixty-nine percent of eyes had the same or better postoperative UCVA than their preoperative best spectacle-corrected visual acuity (BSCVA). Ninety percent of eyes were within +/-0.5 diopter of intended correction. No eye lost more than 1 line of BSCVA. Total higher-order root-mean square (RMS), coma, and spherical aberration values were stable (P<.05). CONCLUSION: The data support the safety and effectiveness of the WaveScan-guided customized laser ablation using the Visx Star S4 system for correction of low to moderate myopia with astigmatism.

Adult↗
PubMed2006

Q-factor customized ablation profile for the correction of myopic astigmatism.

PURPOSE: To compare the results of the Q-factor customized aspheric ablation profile with the wavefront-guided customized ablation pattern for the correction of myopic astigmatism. SETTING: Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland. METHODS: Thirty-five patients were enrolled in a controlled study in which the nondominant eye was treated with the Q-factor customized profile (custom-Q study group) and the dominant eye was treated with wavefront-guided customized ablation (control group). Preoperative and 1-month postoperative high-contrast visual acuity, low-contrast visual acuity, and glare visual acuity, as well as aberrometry and asphericity of the cornea, were compared between the 2 groups. All eyes received laser in situ keratomileusis surgery, and the laser treatment was accomplished with the Wavelight Eye-Q 400 Hz excimer laser. RESULTS: For corrections up to -9 diopters (D) of myopia, there were no statistically significant differences between the 2 groups regarding any visual or optical parameter except coma-like aberrations (3rd Zernike order), where the wavefront-guided group was significantly better 1 month after surgery (P = .002). For corrections up to -5 D (spherical equivalent), the Q-factor optimized treated eyes had a significantly smaller shift toward oblate cornea: DeltaQ15 = 0.25 in Q-factor customized versus DeltaQ15 = 0.38 in wavefront-guided treatment (P = .04). CONCLUSIONS: Regarding safety and refractive efficacy, custom-Q ablation profiles were clinically equivalent to wavefront-guided profiles in corrections of myopia up to -9 D and astigmatism up to 2.5 D. Corneal asphericity was less impaired by the custom-Q treatment up to -5 D of myopia.

Adult↗
PubMed2007

Laser in situ keratomileusis for astigmatism following laser thermal keratoplasty.

We describe 2 cases in which a staged laser in situ keratomileusis procedure was used to treat residual hyperopia and astigmatism after laser thermal keratoplasty. The procedure successfully reduced the spherical equivalent refractive error and residual astigmatism. All eyes maintained their best spectacle-corrected visual acuity and had an uncorrected visual acuity of at least 20/25 at the end of follow-up.

Adult↗