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At least 613 records · Page 34Linked to original sources
PubMed1997

Clear corneal cataract surgery and the correction of myopia, hyperopia, and astigmatism.

PURPOSE: Advances in cataract removal using topical anesthesia through a clear corneal microincision have created a new opportunity to fully correct refractive errors at the time of cataract surgery. This study was undertaken to assess the effectiveness of keratolenticuloplasty (KLP), the simultaneous modification of the cornea at cataract removal to create emmetropia with lens implantation. METHODS: Data were analyzed for 690 consecutive cataract procedures performed between March 1993 and March 1995, with follow-up of 12 to 24 months. Each patient underwent cataract removal with topical anesthesia, clear corneal incision fashioned as an arcuate keratotomy to correct pre-existing astigmatism, intercapsular phacoemulsification, and microinjection of a single-piece elastic intraocular lens (IOL) into the capsular bag to correct spherical error. RESULTS: Preoperative best-corrected visual acuity was worse than 20/50 in all patients; 58% were myopic, 32% were hyperopic, and 57% had astigmatism of greater than 1 diopter (D). Postoperatively, spectacle independence was achieved with uncorrected visual acuity of 20/40 or better in 87% of eyes. The sphere was fully corrected in 78%, within 1 D in 17%, and within 2 D in 5%. No patients were overcorrected. The cylinder was fully corrected in 72%, within 1 D in 26%, and within 2 D in 2%. Of those with residual astigmatism, there was no significant postoperative shift in cylinder axis. There were no sight-threatening complications. All patients were able to resume normal unrestricted activities within 24 hours of undergoing the procedure. CONCLUSIONS: The KLP technique can correct spherical and astigmatic refractive errors, helping individuals become free of eyeglasses after clear corneal cataract surgery.

Adult↗
PubMed1998

Laser in situ keratomileusis for moderate and high myopia and myopic astigmatism.

OBJECTIVE: This study evaluated the predictability, stability, and safety of laser in situ keratomileusis (LASIK) in myopia and myopic astigmatism. DESIGN: The study design was a prospective, unmasked, nonrandomized clinical trial. PARTICIPANTS: Participating were 25 patients with myopia (37 eyes) with astigmatism of less than 1.00 diopter (D), divided into 3 subgroups (-5.00 to -9.90 D, 8 eyes; -10.00 to -14.90 D, 10 eyes; -15.00 to -29.00 D, 19 eyes), and 37 patients with myopia (56 eyes) with corneal astigmatism of 1.00 to 4.50 D, divided into 3 subgroups (-5.00 to -9.90 D, 12 eyes; -10.00 to -14.90 D, 24 eyes; -15.00 to -29.00 D, 20 eyes). INTERVENTION: LASIK was performed using the Automatic Corneal Shaper and the Keracor 116 excimer laser. MAIN OUTCOME MEASURES: Visual acuity, manifest refraction, central corneal islands, ablation decentration, and patient satisfaction were measured. RESULTS: At 12 months, predictability, regression between 1 and 12 months, uncorrected visual acuity (UCVA), loss of two or more lines of corrected visual acuity, and patient satisfaction of the spherical (toric) groups are reported. Subgroups -5.00 to -9.90 D: 100% (75%) +1.00 D; regression less than or equal to 1.00 D in 100% (91.7%); UCVA greater than or equal to 20/40 in 87.5% (70%); none lost two or more lines; 100% (84%) highly satisfied. Subgroups -10.00 to -14.90 D: 60% (78.3%) +/-1.00 D; regression less than or equal to 1.00 D in 100% (87%); UCVA greater than or equal to 20/40 in 77.8% (86.4%); 10% (4.3%) lost two lines; 90% (91%) highly satisfied. Subgroups -15.00 to -29.00 D: 38.9% (21.4%) +/-1.00 D; regression less than or equal to 1.00 D in 72.2% (64.3%); UCVA greater than or equal to 20/40 in 33.3% (40%); 5.6% (7.1%) lost two lines; 78% (50%) highly satisfied. Differences of predictability and change of manifest refraction between subgroups of -5.00 to -9.90 D and -15.00 to -29.00 D were statistically significant. Central islands (decentrations) were observed in 17% (5.6%) of eyes of the spherical and in 16% (4.1%) of the toric group. Overall, the corneal interface was visible in 8.2%. CONCLUSIONS: The LASIK method used in this study showed stability of manifest refraction and adequate uncorrected central visual acuity in a large percentage of patients with myopia up to -15.00 D. Corneal stability was not as uniform. Central corneal islands were observed in a sizable minority of patients despite pretreatment. For myopia greater than 15.00 D, accuracy and patient satisfaction were sufficiently poor to advise against using the authors' treatment technique in these groups. Visually significant microkeratome and laser-related problems were noted in a smaller percentage of patients. Patients with astigmatism correction were less pleased with results than were patients who received spherical corrections.

Adolescent↗
PubMed1999

Laser in situ keratomileusis for correction of myopia and astigmatism after penetrating keratoplasty.

PURPOSE: To determine the safety and effectiveness of laser in situ keratomileusis (LASIK) for visual rehabilitation of residual myopia and astigmatism after penetrating keratoplasty. DESIGN: Prospective, noncomparative case series. PARTICIPANTS: LASIK was performed on 23 eyes of 22 patients unable to wear glasses or contact lenses after penetrating keratoplasty due to anisometropia, high astigmatism, and/or contact lens-intolerance. METHODS: All patients underwent LASIK for visual rehabilitation after penetrating keratoplasty. Uncorrected visual acuity and best spectacle-corrected visual acuity, degree of anisometropia, and corneal transplant integrity were recorded before surgery, as well as at 1 month, 3 months, 6 months, and 12 months after LASIK surgery. RESULTS: The mean spherical equivalent before surgery was -7.58+/-4.42 diopters (D), which was reduced to -1.09+/-2.01 D, -0.79+/-1.84 D, -0.77+/-1.25 D, and -1.57+/-1.20 D, respectively, at 1, 3, 6, and 12 months after LASIK. The mean cylinder before surgery was 3.64+/-1.72 D, which was reduced to 1.98+/-1.15 D, 1.64+/-1.14 D, 1.48+/-0.92 D, and 1.29+/-1.04 D, respectively, at 1, 3, 6, and 12 months after LASIK. Spherical equivalent anisometropia was reduced from a mean of 6.88+/-4.4 D to 1.42+/-1.05 D at the final examination. Best-corrected visual acuity remained the same or improved in 21 of 23 eyes and decreased by 1 and 3 lines in 2 patients. There were no surgical flap or corneal transplant complications. CONCLUSIONS: LASIK is a viable treatment alternative for myopia and astigmatism after penetrating keratoplasty in patients who are contact lens-intolerant. LASIK is more effective in treating myopia than astigmatism after penetrating keratoplasty.

Adult↗
PubMed2000

Paracentral photoablations to correct higher grades of naturally occurring astigmatism.

PURPOSE: To evaluate the efficacy of paracentral ablations in treating higher degrees of naturally occurring myopic and hyperopic astigmatism. SETTING: Augenklinik, Kreiskrankenhaus Bad Hersfeld, Germany. METHODS: Twenty-five eyes (7 with hyperopia, 18 with myopia) with naturally occurring corneal astigmatism greater than 1.75 diopters (D) were treated by excimer laser. The mean refractive cylinder was -4.05 D +/- 1.46 (SD) (range -1.75 to -7.00 D). The intention was to reduce the astigmatism without consideration of the spherical refractive error. Two paracentral ablations were performed by photorefractive keratectomy with treatment zones of 3.5 mm in the flatter meridian of the cornea. Objective refraction, best corrected visual acuity (BCVA), changes in corneal radius, development of haze, and regression were recorded. RESULTS: The paracentral ablations induced a steepening of the corneal radius in the flatter meridian from 8.12 mm (mean preoperative value) to 7. 84 mm (mean postoperative value) and thus reduced the mean refractive cylinder to -1.12 +/- 0.82 D (range 0.00 to - 3.00 D), corresponding to a mean reduction of 78%. No eye experienced a loss of Snellen lines. The preoperative BCVA (mean 20/25; range 20/50 to 20/20) was unchanged postoperatively CONCLUSIONS: Paracentral ablations resulted in a stable corneal curvature immediately after epithelial healing, with a moderate regression over time. Paracentral ablations with the excimer laser appear to be a safe and effective method to correct higher grades of corneal astigmatism.

Adult↗
PubMed2001

Short-term effect of mitomycin-C augmented trabeculectomy on axial length and corneal astigmatism.

PURPOSE: To evaluate the short-term effect of trabeculectomy with adjunctive mitomycin-C (MMC) on corneal astigmatism and axial length. SETTING: Asan Medical Center, University of Ulsan, Department of Ophthalmology, Seoul, Korea. METHODS: Eighteen consecutive eyes of 16 patients having trabeculectomy with adjunctive MMC were prospectively analyzed. Intraocular pressure (IOP) and axial length were evaluated preoperatively and 1, 3, 6, and 12 months postoperatively. Postoperative changes in corneal astigmatism were evaluated using vector analysis. RESULTS: The overall mean induced astigmatism showed with-the-rule change up to 3 months postoperatively followed by an against-the-rule shift. The mean axial length was significantly less postoperatively and changed throughout the 12 month follow-up. There was a positive correlation between postoperative axial length and IOP. Eyes with higher preoperative IOP had a greater decrease in axial length after trabeculectomy with MMC. CONCLUSION: The induced corneal astigmatism after trabeculectomy with MMC was long lasting, although less than that in previous studies. The change in axial length after surgery was significant, especially in eyes with a high preoperative IOP. The decrease in axial length persisted throughout the follow-up.

Adolescent↗
PubMed2000

Photorefractive keratectomy for post-penetrating keratoplasty myopia and astigmatism.

PURPOSE: To determine the safety, effectiveness, and predictability of photorefractive keratectomy (PRK) for the correction of myopia and astigmatism after penetrating keratoplasty. SETTING: Gazi University, Medical School, Department of Ophthalmology, Ankara, Turkey. METHODS: Photorefractive keratectomy was performed in 16 eyes of 16 patients with postkeratoplasty myopia and astigmatism who were unable to wear glasses due to anisometropia and were contact lens intolerant. They were examined for uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and corneal transplant integrity before and after surgery. RESULTS: The mean follow-up after PRK was 26.0 months +/- 15.7 (SD) (range 12 to 63 months). The mean preoperative spherical equivalent refraction of -4.47 +/- 1.39 diopters (D) was -3.39 +/- 1.84 D (P >.05) at the last postoperative visit and the mean preoperative cylinder of -5.62 +/- 2.88 D was -3.23 +/- 1.70 D (P <.05); refractive regression correlated with the amount of ablation performed. The BSCVA decreased in 3 eyes (18.8%), and the UCVA decreased in 2 (12.5%). Six eyes (37.5%) had grade 2 to 3 haze, which resolved spontaneously in 4 eyes within a relatively long time but caused a decrease in BSCVA in 2 (12.5%). Two of the eyes (12.5%) had a rejection episode after PRK and were successfully treated with topical steroids. CONCLUSIONS: Photorefractive keratectomy to correct postkeratoplasty myopia and astigmatism appears to be less effective and less predictable than PRK for naturally occurring myopia and astigmatism. Corneal haze and refractive regression are more prevalent, and patient satisfaction is not good.

Adult↗
PubMed2002

Correcting high astigmatism with piggyback toric intraocular lens implantation.

An 86-year-old man presented for cataract surgery with corneal astigmatism of 5.12 diopters (D). After cataract extraction with small-incision techniques, 2 toric plate-haptic silicone intraocular lenses (IOLs) were implanted in the capsular bag, each with a 3.50 D cylinder add (2.30 D at the spectacle plane). Six weeks postoperatively, corneal astigmatism was 3.38 D at 70 degrees and refractive astigmatism was 1.00 D at 20 degrees. Uncorrected visual acuity was 20/40. No IOL rotation was observed. Implantation of piggybacked toric lenses may be a viable option for correcting moderate to high astigmatism.

Aged↗
PubMed2002

Three-dimensional representation and qualitative comparisons of the amount of tissue ablation to treat mixed and compound astigmatism.

PURPOSE: To compare the shape and volume of the lenticules of corneal tissue ablated for the correction of spherical, cylindrical, and spherocylindrical refractive errors using Boolean operations of theoretical 3-dimensional (3-D) surfaces. SETTING: Department of Ophthalmology, Rothschild Foundation, Paris, France. METHODS: Digital modeling software was used to perform graphic representations of ablated lenticules on 3-D virtual surfaces. Various Boolean operations were performed between different preoperative and postoperative surfaces, and the additional and subtractive properties of ablated theoretical lenticules were analyzed to determine profiles of ablated lenticules for mixed and compound myopic and hyperopic astigmatism. RESULTS: Negative-cylindrical treatment, used to treat simple myopic astigmatism, was equivalent to the combination of a positive-cylindrical and a negative-spherical treatment of the same magnitude. Combining a pure negative-cylindrical and a positive-spherical treatment in a sequential strategy when treating compound astigmatism resulted in redundant ablation (plano lenticule), leading to an unnecessary increase in the amount of tissue ablation. CONCLUSIONS: Negative-cylindrical treatments result in greater tissue ablation than corresponding positive-cylindrical treatments. For any given compound astigmatic error, the strategy using the greater magnitude of positive cylinder incurs the minimal amount of tissue ablation.

Astigmatism↗
PubMed2002

Contact lens fitting to correct irregular astigmatism after corneal refractive surgery.

PURPOSE: To study a technique of contact lens fitting and its visual results in patients with irregular astigmatism induced by corneal refractive surgery. SETTING: Department of Cornea and Refractive Surgery, Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS: This prospective noncomparative study comprised 29 eyes with irregular astigmatism after corneal refractive surgery. Different types of contact lenses were used to correct the astigmatism: hard, gas permeable, hybrid, and toric hydrophilic. Preoperative and postoperative data were analyzed for proper fitting including the preoperative keratometeric reading and corneal ablation zone. RESULTS: Proper contact lens fitting was achieved in 23 eyes (79.3%). In 6 eyes (20.7%), fitting was not possible despite an improvement in best corrected visual acuity (BCVA). Of the eyes with proper fitting, 14 (60.9%) had rigid gas-permeable lenses (9.80 mm), 6 (26.1%) had hydrophilic lenses (14.00 mm), and 3 (13.0%) had hybrid lenses (14.3 mm). Comparing the BCVA with that with spectacles, 23 eyes (79.3%) gained 2 lines or more of BCVA, 4 (13.8%) gained 1 line, and 2 (6.9%) maintained the same acuity as with spectacles. No eye lost lines of BCVA. CONCLUSIONS: Results indicate that contact lens fitting is a good-and sometimes the only-alternative for patients with induced irregular astigmatism. Rigid gas-permeable contact lenses provided the best visual performance and patient tolerance.

Adult↗
PubMed2003

Sutured piggyback toric intraocular lenses to correct high astigmatism.

A 74-year-old woman presented for bilateral cataract surgery, which was performed 3 days apart. Corneal astigmatism was 4.25 diopters (D) in the right eye and 4.87 D in the left. After cataract extraction through 6.0 mm scleral incisions, 2 toric, plate-haptic, silicone intraocular lenses (IOLs), each with a 3.50 D cylinder add power (2.30 D at spectacle plane), were sutured together and implanted in the bag. Both eyes had limbal relaxing incisions postoperatively. Four months postoperatively, corneal astigmatism was 4.50 D in the right eye and 4.00 D in the left. Refractive astigmatism was 0.50 D with an uncorrected visual acuity of 20/40 in both eyes. No IOL rotation was observed. Suturing toric lenses together allows greater correction of astigmatism without concern about counter rotation of the lenses.

Aged↗
PubMed2003

Comparison of photorefractive keratectomy and laser in situ keratomileusis for the treatment of compound hyperopic astigmatism.

PURPOSE: To compare photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for compound hyperopic astigmatism. SETTING: University laser center. METHODS: This prospective nonrandomized study evaluated 41 consecutive eyes (27 patients) that had PRK and 24 consecutive eyes (15 patients) that had LASIK to correct compound hyperopic astigmatism. RESULTS: The mean preoperative error was +3.06 diopters of sphere (DS) +/-1.73 (SD)/+1.31 +/- 0.60 diopters of cylinder (DC) in the PRK eyes and +2.86 +/-1.28 DS/+1.55 +/- 0.96 DC in the LASIK eyes. The mean maximal pain score in PRK eyes was 1.95 +/- 1.19 (range 0.0 to 3.0) in PRK eyes and 0.84 +/-1.12 in LASIK eyes (P=.0014). The uncorrected visual acuity was 20/20 or better in 7.7% of the PRK eyes and 58.3% of the LASIK eyes at 1 month (P<.001) and 57.9% and 66.7%, respectively, at 9 months (P=.586). The mean postoperative spherical error was -0.95 +/- 0.92 D in PRK eyes and +0.33 +/- 0.56 D in LASIK eyes at 1 month (P<.001) and +0.64 +/- 1.01 D and +0.44 +/- 0.57 D, respectively, at 9 months (P=.375). There was no statistically significant between-group difference in the mean residual astigmatic error. Mild peripheral haze (grade 0.5 to 1.0) occurred in 19.5% of PRK eyes and no LASIK eye. No eye in either group lost more than 2 lines of best spectacle-corrected visual acuity. CONCLUSIONS: Photorefractive keratectomy was more painful than LASIK and led to a slower visual recovery, a higher incidence of peripheral haze, and an initial myopic overcorrection, which self-corrected by 3 to 6 months. Efficacy and stability of the astigmatic correction were similar in both groups. Long-term stability of both procedures requires further study.

Adult↗
PubMed2003

Intraocular lens calculations in patients with corneal scarring and irregular astigmatism.

PURPOSE: To compare various methods of estimating corneal power for intraocular lens (IOL) calculation in patients with irregular corneal astigmatism. SETTING: Pepose Vision Institute, St. Louis, Missouri, USA. Case reports and review of the medical literature. RESULTS: Two patients with irregular corneal astigmatism had an IOL exchange after a "surprise" post-cataract-surgery refraction. In the first case, the patient had a post-cataract-surgery refraction of +5.50 -0.75 x 69 and in the second case, a refraction of -7.00 -1.00 x 180. The central corneal power before IOL exchange was assessed using manual keratometry, various computerized videokeratography curvature and power maps, and contact lens overrefraction. The total axial power map (Orbscan(R), Bausch & Lomb), total optical power map (Orbscan), and contact lens overrefraction method provided the most accurate estimates of central corneal power in these 2 patients. CONCLUSION: Computerized scanning-slit videokeratography, which analyzes the anterior and posterior surfaces of the cornea, and the contact lens overrefraction method gave good estimations of corneal power in patients with irregular corneal astigmatism. This type of analysis may improve the accuracy of IOL calculation in patients with corneal pathology and irregular astigmatism.

Adult↗
PubMed1994

Induced astigmatism in a 6.0 mm no-stitch frown incision.

Fifty-five consecutive patients had cataract extraction with a 6 mm no-stitch frown incision and implantation of a 6 mm optic three-piece posterior chamber lens. Vector analysis calculations of diopters (D) of mean induced keratometric astigmatism for this incision were 0.70 D at one day, 0.76 D at one week, 0.50 D at one month, and 0.50 D at three months. The Naeser's polar value showed a mean with-the-rule astigmatism of +0.42 D at one day and -0.08 D against-the-rule astigmatism at three months. The results suggest that the 6.0 mm no-stitch frown incision induces a low postoperative astigmatism and provides a stable incision.

Adult↗
PubMed1993

A new method of analyzing vectors for changes in astigmatism.

This method of astigmatism analysis recognizes the need to define an astigmatism goal, thus allowing the surgeon to obtain precise, separate measures of the magnitude and the angle of surgical error. From this, the surgeon can evaluate what surgery may be required to achieve the initial preoperative goal. An index that measures surgical success is adjusted for the level of preoperative astigmatism. The resulting data allow statistical comparison of multiple surgeries and techniques. This method also assists in resolving the case when spectacle and corneal astigmatism do not coincide.

Astigmatism↗
PubMed1994

Excimer laser correction of myopic astigmatism.

The excimer laser allows the controlled ablation of corneal tissue to correct refractive error. By using a combination of spherical and slit apertures, it is possible to correct both myopia and astigmatism. We report the results of 139 consecutive eyes that had photoastigmatic refractive keratectomy (PARK) for myopic astigmatism (myopia < or = -15.00 diopters [D] with astigmatism < or = -6.00 D) and compare these results with 107 consecutive and concurrent eyes that received photorefractive keratectomy (PRK) for myopia (< or = -15.00 D). The same excimer laser was used by 27 different surgeons. All patients were followed for at least three months. In the PARK group, 68% were within +/- 1.00 D at six months and 77% were within +/- 2.00 D. In the PARK group, these figures were 87% and 97%, respectively. Uncorrected visual acuity of 20/40 or better was achieved in 72% of PARK and 90% of PRK patients at six months. Minor adverse reactions occurred in 6% of PARK and 11% of PRK patients. No significant surgeon effect was seen. Photoastigmatic refractive keratectomy provides a realistic approach to the surgical correction of myopic astigmatism and is comparable to PRK in safety and efficacy.

Adult↗
PubMed1994

Photorefractive keratectomy to correct astigmatism with myopia or hyperopia.

Excimer laser photorefractive keratectomy as a means to flatten the central cornea has generated considerable interest. With this technique radial symmetric ablations can be performed to correct myopic refractive errors and excise superficial corneal pathology. We developed a technique that uses toric ablation to correct astigmatism. A new mask was designed for the MEL 60 Aesculap-Meditec excimer laser. The mask can be rotated regularly over 360 degrees. By varying the angular distances, the surgeon can increase ablation depth in any desired meridian. As a result, both cylindrical and spherical errors can be corrected in one procedure. Seventy-three eyes with either simple, myopic, mixed, or irregular astigmatism were treated. In each category of astigmatism, the surgery reduced the spherical component as well as the overall mean preoperative cylindrical refraction. Our findings suggest that this technique is a safe and effective procedure for correcting different types of astigmatism.

Adolescent↗
PubMed1994

Photorefractive keratectomy for myopic astigmatism: phase IIA of the Federal Drug Administration study (12 to 18 months follow-up). Excimer Laser Study Group.

Excimer laser photorefractive keratectomy was performed on eight eyes to investigate toric ablation of naturally occurring compound myopic astigmatism. Follow-up ranged from 12 to 18 months. In each surgical case, the spherical component was reduced. The cylindrical component was reduced or eliminated in seven of eight eyes and remained unchanged in one eye. However, six of eight eyes had some residual astigmatism and three had 0.75 diopters of cylinder or more. In six of eight eyes the change in axis in the postoperative cylinder varied between 5 and 10 degrees of the preoperative cylinder axis. In one eye with an eccentric ablation, the axis changed by 40 degrees. In two eyes with loss of best corrected visual acuity of one line each, from 20/20 to 20/25, irregular astigmatism and subepithelial haze persisted 18 months after treatment. One eye gained a line of best corrected visual acuity from 20/20 to 20/15. Two eyes were overcorrected. Twenty-five percent of patients achieved 20/20 or better uncorrected visual acuity, 62.5% achieved 20/40 or better uncorrected acuity, and 100% achieved 20/50 or better uncorrected acuity. These preliminary results of excimer laser photoastigmatic keratectomy compare favorably with reports of photorefractive keratectomy for myopia alone. There were no adverse reactions to treatment. The procedure was effective although some residual astigmatism was found in most patients.

Adult↗
PubMed1990

Preoperative astigmatic influence on the predictability of intraocular lens power calculation.

The preoperative and postoperative influence of different parameters on the predictability of formulas used for intraocular lens (IOL) power calculation (axial length, corneal dioptric power, IOL malposition, postoperative astigmatism) has been shown by various authors. In this study, we evaluated the preoperative astigmatic influence on the prediction of postoperative refraction in eyes operated on for cataract with IOL implantation. Three hundred and fifty-nine eyes were evaluated after cataract surgery and IOL implantation. We calculated predictive errors of both the Binkhorst and SRK formulas for each eye. Based on the outcome of the predictive errors we divided the eyes into six groups: three of high and three of low predictability. Preoperative astigmatism in these groups was statistically compared (using the Student's t-test). The preoperative astigmatism was always higher in the group with low predictability than in the group with high predictability (P less than .05).

Astigmatism↗