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PubMedDate not supplied

Comparative results between standard and bitoric nomograms for astigmatism correction.

PURPOSE: To investigate results of excimer laser correction for mixed astigmatism, using two kinds of corneal photoablation; bitoric nomograms for cylinder and standard monotoric procedures. METHODS: Intrastromal photoablation was performed with the Nidek EC-5000 excimer laser and a lamellar keratotomy was created with the Hansatome microkeratome. We selected 46 cases with mixed astigmatism. The first group included 28 eyes (average cylinder 4.15 +/- 0.86 D, sphere 1.37 +/- 0.18 D). In this group, procedures were performed using bitoric nomograms. The second group included 18 eyes (average cylinder 4.05 +/- 0.64 D, sphere 1.67 +/- 0.23 D). In this group ablation was performed with monotoric nomograms. RESULTS: After 6 months in the bitoric group, average residual cylinder was 1.49 +/- 0.24 D, and sphere was -0.57 +/- 0.31 D. In seven cases (25%), re-ablations for astigmatism correction were needed. In the monotoric group, average postoperative cylinder was 1.89 +/- 0,39 D, and sphere was 0.77 +/- 0.28 D. In eight cases (44%), retreatments were planned. CONCLUSION: Bitoric ablations for astigmatic corrections resulted in a decreased frequency of reablation as compared to standard monotoric procedures.

Adult↗
PubMedDate not supplied

Laser in situ keratomileusis for hyperopia and hyperopic astigmatism using the Meditec MEL 70 spot scanner.

PURPOSE: To evaluate safety, predictability, efficacy, and stability of laser in situ keratomileusis (LASIK) for spherical hyperopia and hyperopia with astigmatism. METHODS: In this retrospective study we analyzed the results of 23 eyes of 23 patients who had LASIK for spherical hyperopia (preoperative cylinder < or = 0.75 D) and 44 eyes of 44 patients who had LASIK for hyperopia with astigmatism; (Bausch & Lomb Hansatome microkeratome with a 180-microm plate and a suction ring for a 9.5-mm flap diameter; Asclepion-Meditec MEL 70 G-scan flying spot laser with a 1.8-mm Gaussian beam). RESULTS: In Group 1 (spherical hyperopia), mean preoperative spherical equivalent refraction was +4.88 +/- 2.13 D (range +2.13 to +9.63 D); in Group 2 (hyperopic astigmatism), +4.33 +/- 2.15 D (range +0.50 to +9.50 D). One year after LASIK, mean spherical equivalent refraction was +0.30 +/- 0.90 D (range -0.75 to +2.50 D) in Group 1 and +0.29 +/- 1.27 D (range -3.25 to +3.25 D) in Group 2. In Group 1, 78%, and in Group 2, 42% were within +/- 0.50 D. In Group 1, no eyes lost two or more lines, and one eye (6%) lost one line of best spectacle-corrected visual acuity at 1 year. In Group 2, one eye (4%) lost one line and one eye (4%) lost more than two lines at 1 year. Uncorrected visual acuity of 20/40 or better was achieved in 83% (Group 1) vs. 62% (Group 2) at 1 year; these values improved to 100% vs. 71% for corrections up to +6.00 D. CONCLUSIONS: LASIK with the Meditec MEL 70 G-Scan flying spot laser seemed to be safe and effective for hyperopia and hyperopia with astigmatism for corrections up to +6.00 D. Large flap diameters are necessary to avoid epithelial ingrowth.

Adult↗
PubMedDate not supplied

Laser in situ keratomileusis for compound myopic astigmatism using the Meditec MEL 70 G-Scan excimer laser.

PURPOSE: To determine the safety, efficacy, predictability, and stability of laser in situ keratomileusis (LASIK) in treating patients with myopic astigmatism using the Meditec MEL 70 G-Scan excimer laser. METHODS: Seventy-four eyes of 42 patients with myopia ranging from -4.50 to -9.88 D and astigmatism ranging from 0.50 to 4.00 D who underwent LASIK with the Meditec MEL 70 G-Scan excimer laser and the Summit Krumeich-Barraquer microkeratome were studied. Patients were followed for 1 year. RESULTS: Mean baseline spherical equivalent refraction was -7.12 +/- 1.70 D and cylinder was 1.62 +/- 1.72 D. At 12 months, mean postoperative spherical equivalent refraction was -0.49 +/- 0.57 D and mean refractive cylinder was 0.59 +/- 0.32 D. Mean change in spherical equivalent refraction between 1 and 12 months after surgery was -0.09 +/- 0.31 D, toward myopia. At baseline, no eyes had best spectacle-corrected visual acuity (BSCVA) of 20/20 or better, and 65% had 20/40 or better. At 12 months after surgery, 10% of eyes had BSCVA of 20/20 or better and 88% of eyes had 20/40 or better. The unusually low postoperative BSCVA results were thought to be due to amblyopia or existence of a higher percentage of some optical aberrations in this group of eyes. Mean uncorrected visual acuity was -1.38 +/- 0.42 LogMAR units (20/400) at baseline and -0.29 +/- 0.25 LogMAR units (20/40) at the 12-month postoperative examination. No eyes lost two or more lines of spectacle-corrected visual acuity. No vision threatening complications were observed. CONCLUSIONS: LASIK with the Meditec MEL 70 G-Scan excimer laser appeared to be safe, effective, reasonably predictable, and stable for correction of myopic astigmatism with a spherical component between -4.25 and -8.25 D and a cylindrical component between 0.50 and 4.00 D. However, astigmatism was slightly undercorrected with the algorithm used.

Adult↗
PubMedDate not supplied

Topography-guided laser in situ keratomileusis (TOPOLINK) to correct irregular astigmatism after previous refractive surgery.

PURPOSE: To assess whether topography-driven laser in situ keratomileusis (LASIK) can correct induced corneal irregular astigmatism. METHODS: A prospective non-comparative case series of 41 eyes (38 patients) with irregular astigmatism following corneal refractive surgery, included two groups: Group 1 (26 eyes) with a defined topographic pattern and Group 2 (15 eyes) with no pattern. Ablation was performed using the Technolas 217C excimer laser with a software ablation program (TOPOLINK) based on corneal topography. Uncorrected and best spectacle-corrected visual acuity, manifest and cycloplegic refraction, corneal topography, superficial corneal surface quality, and image distortion were measured. RESULTS: At 6 months follow-up in Group 1 eyes (defined topographic pattern) mean preoperative BSCVA improved from 0.16 +/- 0.11 LogMAR (0.4 to 0) to 0.09 +/- 0.10 LogMAR (0.2 to 0) (P = .001) (safety index of 1.1). In Group 2 eyes (no pattern), mean preoperative BSCVA was 0.18 +/- 0.11 LogMAR (0.4 to 0), similar to the postoperative BSCVA of 0.17 +/- 0.10 LogMAR (0.3 to 0) (safety index of 0.98). Mean postoperative UCVA was > or = 0.3 LogMAR in 25 eyes (96.2%) in Group 1 (efficacy index of 0.8) and 7 eyes (46.6%) in Group 2 (efficacy index of 0.5). Both superficial corneal surface quality and image distortion significantly improved in Group 1; there were no significant changes in Group 2. We reoperated nine eyes (21.9%). CONCLUSIONS: Topographic-assisted LASIK was helpful in selected cases where irregular astigmatism showed a pattern. It was ineffective in undefined irregular astigmatism. Partial correction of the irregularity and regression of the obtained effect was common.

Adult↗
PubMedDate not supplied

Nomogram adjustment of laser in situ keratomileusis for myopia and myopic astigmatism with the Alcon LADARVision system.

PURPOSE: To evaluate the visual and refractive results of conventional (non-wavefront) laser in situ keratomileusis (LASIK) for treatment of myopia and myopic astigmatism using the Alcon LADARVision 4000 excimer laser system and nomogram adjustment techniques. METHODS: A retrospective analysis of 499 eyes that had LASIK for myopia and myopic astigmatism was performed. Preoperative manifest spherical equivalent refraction ranged from -0.43 to -6.00 D and preoperative astigmatism ranged from 0 to -4.75 D. Patients were evaluated during 3 months following surgery. RESULTS: One month after surgery, 72% of eyes examined (298/415 eyes) had uncorrected visual acuity (UCVA) of 20/20 or better. Three months after surgery, 83% of eyes examined (216/261 eyes) had UCVA of 20/20 or better. One and three months after surgery, 82% and 83% of eyes, respectively, were within +/-0.50 D of attempted correction; 97% of eyes were within +/-1.00 D at both 1 and 3 months. No eye lost more than 1 line of best spectacle-corrected visual acuity (BSCVA) at 3 months after surgery. At the 3-month examination, 83% of eyes had UCVA better than or equal to preoperative BSCVA. CONCLUSIONS: Conventional LASIK to correct myopia and myopic astigmatism was safe and effective using the Alcon LADARVision 4000 excimer laser system. Outcomes were substantially improved throughout development of an accurate nomogram, derived from continually updated regression analysis of previous refractive results.

Adult↗
PubMedDate not supplied

Astigmatic power calculations for intraocular lenses in the phakic and aphakic eye.

PURPOSE: To develop sets of equations employed in the power calculations for toric intraocular lenses (IOLs) in phakic or aphakic astigmatic eyes. METHODS: Mathematical operations to convert from standard toric parameters of sphere, cylinder, and axis to astigmatic decomposition components, and vice versa, are presented. These operations are used to derive equations to calculate the ideal toric IOL power for a phakic or aphakic astigmatic eye, predict the postoperative spectacle correction for a selected toric IOL with power other than the ideal power, and back calculate a parameter to be used to optimize predictability of the calculations based on clinical data. RESULTS: Two numerical examples are provided to show how the equations are used with clinical data. CONCLUSION: The equations developed provide a method to perform toric IOL power calculations and supporting operations of predicted postoperative spectacle refraction and optimization of prediction error for phakic and aphakic eyes with astigmatism.

Aphakia↗
PubMedDate not supplied

LASIK for high myopic astigmatism resulting from perforating ocular injury.

PURPOSE: To present a case of successful treatment of high myopic astigmatism after a perforating injury with significant corneal laceration and pupil ectopia using excimer LASIK. METHODS: A 30-year-old man presented for treatment of high myopic astigmatism in his right eye resulting from perforating ocular trauma, which occurred 8 years prior to presentation. The corneoscleral wound repair was performed with posterior chamber intraocular lens implantation. Uncorrected visual acuity (UCVA) in the right eye was counting fingers at 1 m, best corrected to 20/30 with -7.00 + 5.00 x 110. Visual acuity in the left eye was 20/20 with -1.5 D. The patient was unable to tolerate spectacles and contact lenses because of asthenopia and high astigmatism, respectively. As an alternative, LASIK with the Allegretto Wave excimer laser was performed. RESULTS: Three months postoperatively, UCVA was 20/25 in the right eye and 20/15 in the left eye. CONCLUSIONS: This case indicates that LASIK can be a useful surgical method for correcting high myopic astigmatism resulting from ocular trauma with significant corneoscleral laceration.

Adult↗
PubMedDate not supplied

Two-step LASIK with topography-guided ablation to correct astigmatism after penetrating keratoplasty.

PURPOSE: To assess the efficacy, predictability, stability, and safety of a two-step LASIK procedure using topography-guided ablation to correct astigmatism after penetrating keratoplasty. METHODS: Fifteen eyes of 15 patients underwent a two-step LASIK procedure at the Maggiore Hospital of Bologna, Italy. In the first step, a flap was created using the Hansatome microkeratome. In the second step, topography-guided ablation using the LaserSight LSX was planned with interactive software (CIPTA) once topographical and refractive stabilization had been obtained. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cylindrical correction, gain of lines of BSCVA, spherical equivalent refraction, and complications were analyzed. RESULTS: Minimum follow-up was 12 months (range: 12 to 30 months). Uncorrected visual acuity improved in all 15 (100%) eyes. At the last postoperative examination, 11 (73%) eyes had UCVA > or = 20/40. Nine (60%) eyes were within 1.0 diopter (D) of the attempted correction. Mean postoperative astigmatism was -1.67 (range: -3.5 to 0; standard deviation: 1.26). Index of success of astigmatic correction was 0.26. No patient lost Snellen lines of BSCVA. Intraoperative complications included two buttonhole flaps, and postoperative complications included one flap retraction. No further laser treatment was needed. CONCLUSIONS: The two-step LASIK procedure using topography-guided ablation reduces spherical and cylindrical refractive error due to penetrating keratoplasty. Topography-guided ablation also proved to be effective in correcting irregular astigmatism.

Adult↗
PubMed2005

Reduction in astigmatism in manual small incision cataract surgery through change of incision site.

To compare the astigmatism induced by a superior, supero-temporal and temporal incision in manual small incision cataract surgery. Induced astigmatism was analysed by Cartesian coordinates based analysis, using Holladay's system. Mean astigmatism induced by surgery was 1.28 Dx2.9 degrees for superior incision, 0.20 Dx23.7 degrees for supero-temporal incision and 0.37 Dx90 degrees for temporal incision. The study found that induced astigmatism was lower in the temporal and superotemporal groups compared to that in the superior group.

Adult↗
PubMed1999

Photorefractive keratectomy with an ablatable mask and rail system for simultaneous correction of myopia and astigmatism: preliminary results.

BACKGROUND: Alternative methods to correct myopic astigmatism with excimer laser surgery are being examined in an attempt to increase efficacy and reliability. One approach that is developing interest is the incorporation of a polymethylmethacrylate mask into the laser procedure. We examined the efficacy and safety of the Summit Apex Plus laser using a new ablatable mask and rail system. METHODS: Retrospective study based on follow-up of patients at 1 month (59 eyes), 3 months (37 eyes) and 6 months (24 eyes) at an eye laser centre in southern Ontario. Patients were recruited from 19 ophthalmic practices located primarily in the Niagara region and in western New York. Selected patients with naturally occurring myopia and astigmatism were treated with the Summit Apex Plus laser with the mask and rail system. Patients were evaluated for changes in refraction and visual acuity, and complications (including glare, haloes, haze and lines lost of best corrected visual acuity) were assessed. We calculated the surgically induced refractive change using the Holladay 10-step method. RESULTS: At 6 months the average residual sphere for the low myopia group (-7.00 dioptres or less) was -0.60 D and for the high myopia group (greater than -7.00 D) -0.61 D. This result was found to be both stable and accurate over the follow-up period. The cylinder component was reduced irrespective of the amount of preoperative myopia. Vector analysis showed that in most patients the correction of astigmatism was accurate, although slight undercorrection was observed. Complications were minimal, with few residual adverse effects at 6 months. INTERPRETATION: We found the mask and rail technique to be both effective and safe. Refractive change was stable and accurate, although astigmatism was slightly undercorrected. The procedure resulted in few complications, most of which resolved by 6 months.

Adult↗
PubMed1999

Excimer laser photorefractive keratectomy for high myopia and myopic astigmatism.

BACKGROUND AND OBJECTIVE: To determine the efficacy, safety, and predictability of excimer laser photorefractive keratectomy of high myopia and myopic astigmatism. PATIENTS AND METHODS: 76 eyes of 52 patients with myopia from -8.00 to -23.50 diopters (D) with or without astigmatism up to -5.50D were treated with the VISX 20/20 excimer laser (VISK, Santa Clara, CA) and a multi-zone ablation technique. Visual acuity, manifest refraction, corneal haze, and topography were evaluated at 1 week and 1, 3, 6, 12, and 18 months postoperatively. RESULTS: Postoperative refractions were generally stable after 12 months. At the last follow-up all patients were within - 1.96 D of the intended correction. Eighteen months postoperatively, 68% of patients undergoing photorefractive keratectomy (PRK), and 65% of patients undergoing photo astigmatic refractive keratectomy (PARK), were within 1 D of planned refraction. Furthermore, 87% of patients after PRK and 80% of patients after PARK had a visual acuity of 20/40 or better. CONCLUSIONS: High myopia with or without astigmatism was successfully treated in most of the patients using PRK. The stability of the postoperative refraction during the first 18 months seems to be good. The incidence of adverse effects was low but improvements in the future should further reduce complications, thus increasing the safety of refractive procedures.

Adult↗
PubMed1999

[Comparison of EyeSys videokeratoscope algorithms in the evaluation of idiopathic and postoperative astigmatism].

PURPOSE: To compare the accuracy and reproducibility of the Eye Sys videokeratoscope algorithms for analyzing idiopathic and surgery-induced astigmatism analysis. METHODS: Refractive astigmatism, videokeratoscopy (axial, tangential and refractive power), autorefractometry, autokeratometry, and keratometry were recorded in 20 patients with idiopathic astigmatism, 40 patients who had undergone cataract surgery and 40 patients who had undergone penetrating keratoplasty. For each eye, 2 successive videokeratoscopy were recorded. RESULTS: Both cylinder and axis provided by the tangential algorithm are significantly less reproducible than the cylinder and axis provided by the axial and refractive algorithms (P < 0.001). Cylinders provided by the axial and refractive algorithms showed a stronger correlation with subjective cylinder (rs > 0.89; p < 0.001) than the cylinder provided by the tangential algorithm (rs = 0.66; p < 0.001). Both keratometric axis and autokeratometric axis showed the strongest correlation with subjective axis (rs > 0.92; p < 0.001). The accuracy and reproducibility were higher for the topographic "bow tie" patterns than for the other topographic patterns. CONCLUSION: The axial and refractive algorithms of the Eye Sys videokeratoscope are more accurate and reproducible than the tangential algorithm for analyzing idiopathic or surgery-induced astigmatism.

Algorithms↗
PubMed1999

Six-month results of hyperopic and astigmatic LASIK in eyes with primary and secondary hyperopia.

PURPOSE: To assess the safety and efficacy of laser in situ keratomileusis (LASIK) for hyperopia and hyperopic astigmatism and develop a LASIK nomogram for primary hyperopia or hyperopia secondary to myopic refractive surgery using the VISX STAR S2. METHODS: Prospective evaluation of LASIK in 46 primary eyes and 29 secondary eyes with fogged manifest sphere from +0.5 diopters (D) to +6.0 D and cylinder from 0 to +5.0 D. RESULTS: Mean manifest spherical equivalent (SE) in patients with primary hyperopia was +2.50 D +/- 0.93 preoperatively and +0.70 D +/- 1.19 at 6 months. At 6 months, 79% of primary hyperopes had uncorrected visual acuity (UCVA) of 20/40 or better; 63% were within +/- 1 D of emmetropia. One primary hyperope lost 2 lines of best spectacle-corrected vision (BCVA) at 1 month. Complications included transient epithelial defect (6.5%), epithelial cells in the interface (4.3%), diffuse lamellar keratitis (4.3%), haze (2.2%), and mild irregular astigmatism (2.2%). In those with secondary hyperopia, mean manifest SE was +1.70 D +/- 0.82 preoperatively and -0.27 D +/- 0.95 at 6 months. At 6 months, 83% of secondary hyperopes had UCVA of 20/40 or better; 74% were within +/- 1 D of emmetropia. No secondary hyperope lost > or = 2 lines of BCVA. Complications included intraoperative bleeding (3.4%), intraoperative epithelial defect (3.4%), transient interface debris (3.4%), significant dry eye (3.4%), blood in interface (3.4%), irregular astigmatism (6.9%), slight decentration (6.9%), trace haze (6.9%), mild epithelial ingrowth not requiring removal (3.4%), or corneal irregularity (3.4%). CONCLUSION: These early data suggest that LASIK for hyperopia from +0.5 to +6 D and astigmatism from 0 to +5 D using the VISX STAR S2 benefits from a nomogram adjusted for preoperative refraction, age, and prior refractive surgery and is safe and effective. Patients with secondary hyperopia achieved more correction than those with primary hyperopia, although the accuracy and predictability of LASIK in both groups has improved with the nomogram adjustments.

Adult↗
PubMed2000

Is pseudophakic astigmatism a desirable goal?

PURPOSE: To determine whether pseudophakic astigmatism is a desirable goal, and if so, which one is better: against-the-rule (ATR) or with-the-rule (WTR). METHOD: Eyes were included only if they had an uncorrected vision > or = 6/18 and N/18. Three groups, of 40 patients each were evaluated: group 1, pseudophakes with neutral astigmatism; group 2, with ATR and group 3, with WTR astigmatism Unaided distance and near visual acuity was recorded. Statistical analysis was performed using the chi-square test for independence. RESULTS: Unaided distance vision of > or = 6/7.5 was achieved in 19 eyes (47.5%) of group 1 (neutral), 12 eyes (30%) in group 2 (ATR), and 5 eyes (12.5%) in group 3 (WTR) (p = 0.0133, significant). Unaided near vision of > or = N/9 was achieved in 17 eyes (42.5%) in group 1 (neutral), 34 eyes (85%) in group 2 (ATR), and 10 eyes (25%) in group 3 (WTR) (P < 0.001, significant). Group 1 (neutral) fared the best for unaided distance visual acuity. Group 2 (ATR) was better than in group 3 (WTR) for distant vision. Group 2 (ATR) fared the best for unaided near vision. CONCLUSION: ATR astigmatism could be a desirable goal after cataract extraction in selected populations because the largest proportion of these cases achieved good unaided near vision with acceptable distant vision.

Astigmatism↗
PubMed2002

Suturing technique for control of postkeratoplasty astigmatism and myopia.

PURPOSE: We previously demonstrated that selective suture removal reduces keratoplasty astigmatism; however, a myopic shift was induced with increasing number of interrupted sutures removed. This study is an attempt to determine the effects of a modified surgical technique on postkeratoplasty myopia, astigmatism, and anisometropia. METHODS: Optical penetrating keratoplasties were performed on 92 eyes of 84 patients. The study group consisted of 92 consecutive penetrating keratoplasties performed using 12 interrupted 10-0 nylon sutures and a tight 12-bite continuous suture, and use of an average keratometry (K) reading of 46.00 diopters for eyes undergoing combined and intraocular lens (IOL) exchange procedures. All patients had refraction, keratometry, and videokeratoscopy postoperatively, starting at 6 weeks and at the completion of selective suture removal. RESULTS: Prior to suture removal, the average spherical equivalent was -0.160 +/- 3.59 diopters. It was -1.58 +/- 3.66 diopters at the completion of suture removal at 1 year and -1.44 +/- 3.72 at the last follow-up visit, averaging 20.7 months. Final residual refractive, keratometric, and videokeratoscopic astigmatism was 2.81 +/- 1.82, 4.19 +/- 2.94, and 3.58 +/- 2.03 diopters, respectively. Anisometropia, using the spherical equivalent of the operated and fellow eyes, was 2.49 +/- 2.25 diopters at completion of the study. A best corrected visual acuity of 20/50 or better was achieved in 50 patients (59%). CONCLUSIONS: Low myopic spherical equivalent refraction and anisometropia with moderate residual astigmatism were achieved by using tighter continuous sutures, an average K reading of 46 diopters for calculation of IOL power, and selective removal of fewer sutures.

Adult↗
PubMed2003

Effect of pterygium excision on pterygium induced astigmatism.

Pterygium is known to affect refractive astigmatism, which can have a significant impact on vision. This study was undertaken to evaluate the effect of pterygium excision on refractive astigmatism. Thirty-six eyes with primary pterygium with astigmatism of 2D or more were analysed before and after pterygium excision. Astigmatism increased with the increase in the grade of pterygium (P = 0.000001). The preoperative refractive cylinder decreased from 4.60 +/- 2D to 2.20 +/- 2.04D (P = 0.00001) after pterygium excision.

Astigmatism↗
PubMed1992

[Postoperative astigmatism. 3.5 mm scleral tunnel incision and implantation of a HEMA posterior chamber lens vs 7 mm scleral step incision and implantation of a PMMA posterior chamber lens].

In a prospective study, two groups of 35 patients each were compared following phacoemulsification and posterior lens implantation. Both groups were followed up to evaluate the evolution of the postoperative astigmatism during a minimum of 6 months. In group A, a HEMA posterior chamber lens was implanted through a 3.5 mm scleral tunnel incision. In group B, a PMMA posterior chamber lens was implanted through a 7 mm scleral step incision. The data were analyzed for the whole observation time with reference to preoperative, early postoperative, absolute and induced astigmatism. Different subgroups were formed. Vector analysis was performed in both groups in order to determine surgically induced axial changes, e.g., the intensity and direction of the power working on the cornea. The results were compared. Group A showed lesser early postoperative astigmatism than group B; however, group A also returned to the preoperative values more quickly. Both groups exhibited a shift towards against-the-rule astigmatism.

Astigmatism↗
PubMed2003

[Corneal ring segments (INTACS) for the treatment of asymmetrical astigmatism of the keratoconus. Follow-up after 2 years].

OBJECTIVE: To evaluate the use of corneal ring segments (INTACS) for the treatment of asymmetrical astigmatism in keratoconus. MATERIAL AND METHODS: This prospective study involved nine eyes of seven patients who were operated on between December 1998 and June 2000. A case of keratoconus with opacified cornea was excluded from this study. The patients chosen were contact lens-intolerant. The surgical intervention was carried out under topical anesthesia. The INTACS (Addition Technology) corneal ring insert was inserted approximately 68% of the peripheral corneal depth and was centered to the cone of the cornea. RESULTS: No intraoperative complications occurred. We noted a flattening of the central cornea and a decrease in irregular astigmatism for all patients. Mean preoperative uncorrected visual acuity was less than 1/10. Postoperatively two eyes had an uncorrected visual acuity of 10/10, seven eyes showed an improvement from an uncorrected visual acuity of 2/10 to 7/10. CONCLUSION: We have observed that the flattening effect of INTACS inserts on the soft corneal keratoconic tissue and on the high astigmatic tissue seems greater than that produced in normal cornea. Implantation of INTACS resulted in a significant reduction in asymmetrical astigmatism of the keratoconus.

Adult↗