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At least 793 records · Page 44Linked to original sources
PubMed2002

Laser-assisted subepithelial keratectomy for low to high myopia and astigmatism.

PURPOSE: To evaluate the safety and efficacy of laser-assisted subepithelial keratectomy (LASEK) for the treatment of low to high myopia and astigmatism. SETTING: Solo private practice, Mountain View, California, USA. METHODS: Laser-assisted subepithelial keratectomy was performed in 146 eyes of 83 consecutive patients with myopia or myopic astigmatism using a VISX Star S2 excimer laser (72 eyes) or a Nidek EC-5000 excimer laser (74 eyes). The mean preoperative myopic spherical equivalent was -5.32 diopters (D) (range -1.25 to -14.38 D). Data were collected prospectively with a follow-up of 1 to 12 months. Outcome measurements included uncorrected visual acuity (UCVA), manifest refraction, best spectacle-corrected visual acuity (BSCVA), corneal haze, and complications. RESULTS: After 6 and 12 months, no eye lost 2 or more lines of BSCVA. After 6 months, the UCVA was 20/20 in 57% of eyes and 20/40 or better in 96%. After 12 months, it was 20/20 in 56% of eyes and 20/40 or better in 96%. No eye developed corneal haze that affected visual acuity. There were no serious or vision-threatening complications. CONCLUSIONS: Laser-assisted subepithelial keratectomy was safe and effective in treating a wide range of myopia and astigmatism. The potential advantages of LASEK over laser in situ keratomileusis (LASIK) include the elimination of stromal flap complications and greater choice in patient selection. The disadvantages include varying degrees of pain for 2 days and blurry vision for several days postoperatively.

Astigmatism↗
PubMed2002

Epi-LASEK for the correction of myopia and myopic astigmatism.

PURPOSE: To analyze patient results after laser-assisted subepithelial keratectomy (epi-LASEK) for myopia and myopic astigmatism. SETTING: Private practice setting, Columbus, Ohio, USA. METHODS: Three hundred forty-three eyes of 188 patients with myopia or myopic astigmatism were prospectively evaluated after having epi-LASEK by a single surgeon using the VISX Star S2 excimer laser. Uncorrected visual acuity (UCVA), manifest refraction, postoperative pain, time to epithelial healing, and postoperative haze were recorded. The patients were followed for up to 6 months. RESULTS: The mean preoperative sphere and cylinder were -5.42 diopters (D) +/- 2.62 (SD) (range -1.0 to -14.0 D) and 0.87 +/- 0.75 D (range 0 to 4.75 D), respectively. At 1 week, the mean UCVA was 20/30. At 6 months, it was 20/40 or better in 98% of patients. At 3 months, 78% and 92% of patients were within +/-0.5 D and +/-1.0 D, respectively, of the intended correction. This improved to 85% and 94%, respectively, at 6 months. The mean time to epithelial healing was 4.76 days (range 3 to 9 days). Most patients (87%) reported no postoperative pain. In the first 3 months, haze was noted in 1.6% of patients. CONCLUSIONS: Epi-LASEK appeared to be a safe and effective treatment for the correction of myopia and myopic astigmatism. Most patients achieved postoperative visual acuities comparable to those with laser in situ keratomileusis and photorefractive keratectomy. There was a low incidence of haze and pain postoperatively.

Astigmatism↗
PubMed2003

Laser in situ keratomileusis correction of mixed astigmatism by bitoric ablation.

PURPOSE: To evaluate the effect of bitoric ablation (cross cylinder) in 1 eye and ordinary monotoric treatment in the contralateral eye of patients with mixed astigmatism. SETTING: Instituto Oftalmológico de Alicante and University of Miguel Hernández, Alicante, Spain. METHODS: A comparative consecutive study was initiated in 30 eyes of 15 patients with mixed astigmatism. In each patient, 1 eye was treated with bitoric ablation (Group 1) and the other eye was treated with monotoric ablation (Group 2). The decision to treat with bitoric or monotoric ablation was randomized. All patients were operated on by the same surgeon (J.L.A.) and examined by the same investigators (M.J.A., M.A.H.). All completed a 6-month follow-up. Visual acuity was estimated by transforming the Snellen chart readings into logMAR equivalents. In Group 1, theoretical ablation was also performed on glass slides by making 3 ablation profiles (positive, negative, and bitoric). RESULTS: There was a statistically significant improvement in the mean uncorrected visual acuity (UCVA), the mean spherical equivalent (SE), and the mean refractive cylinder in Group 1 (P<.0001, P =.04, P<.0001, respectively) and in the mean refractive cylinder in Group 2 (P =.01). Better results were obtained in the mean incremental change in UCVA, best corrected visual acuity, SE, and refractive cylinder in Group 1. CONCLUSIONS: Treatments to correct mixed astigmatism vary in ablation profiles and depth. Bitoric ablation appears to be safer, more effective, and more tissue sparing than the standard treatment.

Adult↗
PubMed2003

Effect of central corneal thickness on surgically induced astigmatism in cataract surgery.

PURPOSE: To evaluate the effect of central corneal thickness (CCT) on surgically induced astigmatism (SIA) in cataract surgery using temporal clear corneal incisions. SETTING: Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea. METHODS: The retrospective nonrandomized clinical study comprised 129 eyes that had cataract surgery performed through a sutureless temporal clear corneal incision. Eyes were categorized according to the axis of the preoperative astigmatism: against the rule (ATR, 0 to 45 degrees; n = 64) or with the rule (WTR, 46 to 90 degrees; n =65). Corneal topography was taken preoperatively and 1 day and 2 months postoperatively to evaluate the change in the cornea. The SIA was calculated using the polar method from simulated keratometric readings obtained with topography. Correlations between SIA and CCT were analyzed by linear regression analysis and compared between the ATR and the WTR groups. RESULTS: One day postoperatively, the SIA was negatively correlated with CCT in the ATR group but not in the WTR group (P =.050 versus P =.92; linear regression analysis). At 2 months, the correlation between CCT and SIA was no longer statistically significant. CONCLUSIONS: Central corneal thickness was negatively correlated with the amount of SIA immediately postoperatively when the preoperative astigmatism was ATR. The correlation was not present 2 months after surgery. These results may be applied to abnormally thin corneas such as those after keratorefractive surgery.

Aged↗
PubMed2003

Elliptical ELSA (LASEK) instruments for the treatment of astigmatism.

PURPOSE: To investigate newly designed, elliptical ELSA (excimer laser subepithelial ablation) instruments for the treatment of astigmatism. SETTING: University Eye Clinic Regensburg, Regensburg, Germany, and the Rayne Institute, Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom. METHODS: The new ELSA instrument set consists of an elliptical microtrephine (11.0 mm x 8.0 mm) with a 70 microm calibrated blade and an elliptical alcohol cone (11.5 mm x 8.5 mm). With this instrument set, ELSA (the laser-assisted subepithelial keratectomy [LASEK] described by Camellin) was performed in 34 astigmatic eyes. The cylindrical correction was between 1.00 diopters (D) and 3.50 D and the spherical correction, between -0.75 D and -8.75 D. In all eyes, the follow-up was 6 months. The postoperative refractive outcome was analyzed using Alpins vector analysis. RESULTS: Excimer laser subepithelial ablation was performed without intraoperative complications in all eyes. At 6 months, the mean spherical correction was -0.04 D +/- 0.27 (SD) (range +0.75 to -0.75 D) and the mean cylindrical correction, 0.27 +/- 0.23 D (range 0 to 0.75 D). The mean index of success was 0.18 +/- 0.15. CONCLUSIONS: With the elliptical instruments, ELSA was an effective and safe surgical procedure for astigmatism.

Astigmatism↗
PubMed1993

Astigmatism after phacoemulsification with posterior chamber lens implantation: small incision technique with fibrin adhesive for wound closure.

The scleral pocket technique has dramatically changed wound closure after phacoemulsification with implantation of a posterior chamber lens. The use of single-stitch technique and wound closure by fibrin adhesive is now possible. We conducted a comparative study of 385 consecutive patients; 167 received only fibrin glue for wound closure and 218 had the single-stitch procedure. No complications were observed in either group. Surgically induced astigmatism was smaller in the fibrin group (vector analysis: 0.80 diopters [D]) than in the single-stitch group (vector analysis: 0.99 D). Minimal, statistically insignificant different against-the-rule astigmatism developed: single-stitch group: -0.07 D (Cravy), -0.09 D (Naeser); fibrin adhesive group: -0.13 D (Cravy), -0.17 D (Naeser). These results suggest that postoperative against-the-rule astigmatism can be prevented with fibrin glue.

Astigmatism↗
PubMed1994

Evaluating surgically induced astigmatism.

Using a modification of vector analysis for calculating surgically induced astigmatism, we describe a simple method that divides the induced cylinder into two orthogonal components. This decomposition allows with-the-rule and against-the-rule astigmatic changes to be calculated for individual case analysis, as well as for statistical analysis of aggregate data. Because it is based on the true induced cylinder, as determined by optical principles, this method overcomes some of the problems associated with earlier methods of evaluating surgically induced astigmatism.

Astigmatism↗
PubMed1993

Reduction of postoperative against-the-rule astigmatism by lateral incision technique.

A group of 80 preoperative against-the-rule (AR) eyes had cataract removal and intraocular lens implantation with lateral (temporal) incision and suturing. Fifty-six of the 80 eyes had extracapsular cataract extraction (ECCE) and 24 had phacoemulsification (KPE) with capsulorhexis. For both procedures, subgroups (21 of ECCE, ten of KPE) with high preoperative AR astigmatism (> or = -2.0 D) were evaluated. Analysis of the postoperative data provided the following: (1) induced postoperative cylinder decrease, (2) effect of cutting and not cutting sutures, (3) induced axial shift, (4) postoperative astigmatic change as a function of time, and (5) comparative effectiveness of ECCE and KPE lateral incision procedures in reducing postoperative AR astigmatism.

Astigmatism↗
PubMed1994

Treatment of myopic astigmatism with the 193 nm excimer laser utilizing aperture elements.

In this paper, we examine the 193 nm excimer laser's efficacy and safety in treating myopic astigmatism. The VISX Twenty/Twenty excimer laser uses aperture elements to effect astigmatic photorefractive keratectomy. In 70 patients with six months follow-up, the average postoperative sphere was -0.14 and the average postoperative cylinder was -0.54. Seventy-one percent of these patients had uncorrected visual acuity of 20/40 or better at six months. In 12 patients with one year follow-up, the average postoperative sphere was -0.05 and the average postoperative cylinder was -0.59. Eighty-three percent of these patients had uncorrected acuities of 20/40 or better; none had a clinically significant loss of best corrected acuity. This investigation demonstrates that the excimer laser can be used to treat myopic astigmatism successfully.

Astigmatism↗
PubMed1991

Routine use of a lateral approach to cataract extraction to achieve rapid and sustained stabilization of postoperative astigmatism.

After observing that lateral under-riding scleral pocket incisions and closures decayed very little and required full correction on the table to achieve the desired reduction in astigmatism, I began performing routine lateral approaches to planned extracapsular cataract extraction (ECCE). The result was an improvement in early and prolonged stabilization of keratometric astigmatism. This improvement was statistically significant when compared with the identical surgery performed in the vertical meridian. Using a 6.5 mm scleral pocket incision and the same suture material and closure technique, I found that the results of phacoemulsification via vertical and lateral approaches were not statistically different from the planned ECCE via lateral approach. Scleral pocket incisions and modified shoelace closures with 11-0 polyester suture were used in all cases; no suture removal was performed. The early visual recovery with planned ECCE via lateral approach was equivalent to that with phacoemulsification but did not require the expensive instrumentation or the "phaco learning curve." The minimal and stable postoperative astigmatism, along with early and sustained visual recovery possible with ECCE via lateral approach, may reduce the potential benefit of mini-incision and foldable intraocular lens surgery.

Aged↗
PubMed1990

Comparison of the effect of topical corticosteroids and nonsteroidals on postoperative corneal astigmatism.

A controlled study compared the effects of a topical steroid (1% prednisolone acetate) and a topical nonsteroidal anti-inflammatory agent (0.03% flurbiprofen) on postoperative changes in corneal astigmatism in a series of patients having phacoemulsification and posterior chamber lens implantation through a 6.5 mm scleral pocket incision. The incisions were closed with a continuous running 10-0 monofilament nylon suture under tonometric and keratometric control. The results of the study showed that both agents demonstrated similar postsurgical astigmatic decay curves; however, the group receiving the nonsteroidal agent had an earlier decay of iatrogenically induced astigmatism. Approximately 80% of cases receiving the nonsteroidal agent completed the postoperative course without the use of topical steroids, indicating that in some cases steroids may be avoided after cataract removal.

Administration, Topical↗
PubMed1986

Quantifiable astigmatism correction: concepts and suggestions, 1986.

Astigmatism control and correction is of great concern to refractive, cataract, and corneal surgeons. This paper presents a systematic surgical approach to astigmatism based on my experience. Concepts to improve predictability of astigmatic keratotomy are offered for consideration.

Astigmatism↗
PubMed1987

Graded nonintersecting transverse incisions for correction of idiopathic astigmatism.

We present the results of a consecutive series of graded transverse (T) incisions for correcting idiopathic astigmatism evaluated by vector analysis, a method not previously used to report T-incision results. In fact, no clinical studies on the results of the T-incision method have been reported. For comparison with conventional reporting methods, the results of graded T incisions on a series of eyes were evaluated, using both vector analysis and simplified analytic procedures. Sixty eyes were evaluated following surgery based on the Thornton guide for astigmatism correction. The mean preoperative cylinder in the series was 1.5 diopters (D) (SD = 0.43, range 1.00 D to 2.25 D); mean postoperative cylinder was 0.4 D (SD = 0.61, range 0 to 3.75 D). The mean decrease of 1.1 D was statistically significant. The results show that it is possible to quantify astigmatism correction using vector analysis.

Adult↗
PubMed1987

Deep versus appositional suturing of the scleral pocket incision for astigmatic control in cataract surgery.

A study was performed to determine whether alternative suturing techniques of a standard wound play a significant role in the immediate and long-term postoperative course of corneal astigmatism. Two groups of patients had phacoemulsification and posterior chamber lens implantation through a scleral pocket incision closed with a continuous suture. In one group, the sutures were apposed to the posterior edge of the scleral incision; in the second group, deep suture placement designed to incorporate the internal layer of the scleral pocket was used. The deep suture group demonstrated significantly reduced transient iatrogenic astigmatism but the eventual healed astigmatic results were similar for the two groups. The deep suture group developed no filtration blebs; these did occur in three of 50 cases sutured with the appositional technique.

Astigmatism↗
PubMed1988

Effect of penetrating keratoplasty using grafts of various sizes on keratoconic myopia and astigmatism.

The records of 72 consecutive keratoconic eyes undergoing penetrating keratoplasty were reviewed for changes in myopia and astigmatism. Ages of the patients averaged 32.7 years. All sutures were removed after three months. Follow-up average was 40.2 months. Results showed an average decrease in myopia of 6.63 diopters (D) in 60 eyes (82.86%) and an average increase in myopia of 1.88 D in 12 of 70 eyes (17.14%). The decrease/increase in myopia and postoperative astigmatism was compared for grafts equal to the opening, grafts smaller than the opening, and grafts larger than the opening. The largest average decrease in myopia was 13.86 D (range 6.63 to 20.00), which occurred when a graft smaller than the opening was used (P less than .01). This group also showed the least postoperative astigmatism (2.82 D) (P less than or equal to .01). From this study, it appears that the use of a graft 0.25 mm smaller than the trephine opening in the host (i.e., 7.50 mm graft/7.75 mm opening) for penetrating keratoplasty in keratoconus is justified. A prospective study is now in progress.

Adolescent↗
PubMed1989

Surgically induced astigmatism in human cadaver eyes.

A human cadaver eye model was used to study the effects of various sized limbal and scleral-pocket-type incisions on corneal astigmatism. Limbal incisions of 5.0 mm and 10.0 mm and scleral pocket incisions of 3.5 mm and 7.0 mm were carefully placed in human cadaver eyes. These wounds were closed in a uniform fashion, first loosely and then tightly, using interrupted 10-0 nylon sutures. Pre-incision and post-incision keratometer readings were taken and the net change in astigmatic error was calculated. The results indicate that tighter sutures, larger wound size, and limbal rather than scleral-pocket-type incisions were associated with a greater degree of immediate postoperative astigmatism in the cadaver eye.

Astigmatism↗
PubMed1989

Long-term corneal astigmatism related to selected elastic, monofilament, nonabsorbable sutures.

The long-term decay of surgically induced corneal astigmatism following planned extracapsular cataract extraction has been studied in 395 patients who had limbal or scleral pocket incisions of 60 to 140 degrees. Limbal incisions were closed with a full-thickness shoelace closure; scleral pocket incisions, with a new, modified shoelace closure. Suture material was 10-0 nylon, 9-0 nylon, 10-0 polypropylene (Prolene), and 10-0 polyester (Mersilene). The nylon sutures demonstrated clinically significant hydrolysis beginning at five months (10-0) and 12 months (9-0). Because of the adverse hydrolytic effects, 10-0 nylon was eliminated from the scleral pocket closure group. The hydrolysis of 9-0 nylon caused excessive late astigmatic changes in patients who did not heal normally. Prolene and Mersilene showed no tendency toward hydrolysis; however, the elasticity of Prolene produced more against-the-rule change in astigmatism than desired even though it was stable over the long run. I stopped using nylon sutures in cataract (and keratoplasty) wound closures and switched to routine use of Mersilene.

Adult↗
PubMed1989

Induced astigmatism in small incision cataract surgery.

The use of smaller cataract incisions is thought to induce less astigmatism, resulting in a more stable refraction. I analyzed the astigmatic changes in 99 cataract/intraocular lens patients with 4.0 mm incisions. Preoperative keratometry measurements were compared with those obtained one week, one month, and three months postoperatively. These changes, analyzed by vector analysis, revealed 0.13 D of induced with-the-rule astigmatism at one week, degrading to 0.22 D of against-the-rule at three months. This compares favorably with previously reported results of 6.0 mm and 10.0 mm incisions. This low amount of induced cylinder and rapid stabilization of the wound confirms an advantage of small incision surgery.

Astigmatism↗