Flap-induced refraction change in LASIK after penetrating keratoplasty

PURPOSE: To further analyze the refractive and topographic changes occurring with microkeratome lamellar keratotomy and to investigate possible factors associated in eyes with previous penetrating keratoplasty (PK). METHODS: The Hansatome microkeratome was used to create a lamellar corneal flap in 21 eyes of 19 patients after PK. The laser ablation was not performed in the first stage. Pre- and postoperative refractions and corneal topographies were compared to evaluate possible changes induced by the keratotomy. RESULTS: Twenty-one eyes were analyzed in this study. Mean time between PK and lamellar keratotomy was 36.63 +/- 28.23 months (range: 12 to 120 months). No microkeratome-related flap complications occurred. Previous to the keratotomy, the mean spherical equivalent refraction was -4.26 +/- 3.41 diopters (D), mean refractive astigmatism was -4.71 +/- 2.27 D, and mean topographic astigmatism was 5.28 +/- 2.94 D. After keratotomy, eyes showed statistically significant changes in spherical equivalent refraction from preoperative values (P = .025), with 3 eyes showing changes > 2.00 D. Average refractive and topographic astigmatism did not change significantly from before to after keratotomy. However, surgically induced astigmatism (SIA) calculated through vector analysis was > 1.01 in 11 (52.4%) eyes. A statistically significant correlation was found between the SIA values and preoperative refractive astigmatism (P = .025). CONCLUSIONS: Lamellar keratotomy as part of two-stage LASIK in eyes with prior PK led to refractive changes that justify the use of this technique, especially in eyes with high degrees of preoperative astigmatism.     

Effects of lamellar keratotomy on postkeratoplasty astigmatism

AIM: To determine the changes in postkeratoplasty astigmatism induced by lamellar keratotomy. METHODS: A prospective, non-randomised comparative trial of patients undergoing a hinged lamellar corneal flap for treatment of significant astigmatism after penetrating keratoplasty. Uncorrected visual acuity, best corrected visual acuity, refraction, and corneal topography were assessed at 1 and 3 months after the lamellar keratotomy. RESULTS: 17 eyes in 16 patients (13 M, 3F) were included in the study (mean age 48.2 years; range 20-86 years). Six of 17 eyes (35.3%) changed more than 1 dioptre (D) in spherical equivalent by 3 months. Nine of 17 eyes (52.9%) changed more than 1 D in sphere by 3 months. 12 of 17 eyes (70.6%) changed more than 1 D in refractive cylinder. Seven patients of 15 (46.7%) changed more than 1 D in corneal power as measured topographically. Five of 17 eyes (29.4%) changed in refractive cylinder axis more than 15 degrees and this was similar to the change measured topographically of four of 15 eyes (26.7%). Vector analysis showed 60% of eyes had a surgically induced astigmatism (SIA) vector of more than 1 D, including a net corneal astigmatism decrease of more than 1 D in four eyes and increase of more than 1 D in two eyes at 3 months after surgery. Complications of the lamellar keratotomy included two partial buttonholes and one partial wound dehiscence. CONCLUSIONS: The creation of a lamellar flap alone can have significant effects on the astigmatism following penetrating keratoplasty. LASIK for correction of postkeratoplasty astigmatism may be more accurately performed as a two stage procedure rather than a single stage, after the corneal effects of the lamellar keratotomy have stabilised.     

Two-stage laser in situ keratomileusis to correct refractive errors after penetrating keratoplasty

PURPOSE: To evaluate the effect of a two-stage laser in situ keratomileusis (LASIK) procedure on eyes with high astigmatism and/or anisometropia after penetrating keratoplasty. METHODS: Eleven postoperative penetrating keratoplasty eyes were included in a prospective, non-controlled study. All patients had at least 4.00 D of astigmatism and/or at least 3.00 D of anisometropia and were spectacle and contact lens intolerant. Two-stage LASIK was performed; in the first stage a hinged corneal flap 160 microm in thickness and 9 mm in diameter was created. After stabilization of corneal shape (1 to 3 months after keratotomy), the corneal flap was lifted and laser refractive treatment (second stage) was performed. RESULTS: After the first stage, a statistically significant reduction in refractive astigmatism (P<.01) was recorded. In all eyes but one, best spectacle-corrected visual acuity was maintained or improved after the procedure. Three months after the second stage, refractive astigmatism in 8 of 11 eyes (73%) was within +/- 1.00 D, and spherical equivalent refraction in 9 of 11 eyes (82%) was within +/- 1.00 D of intended correction. Preoperative irregular astigmatism persisted in three patients (3 eyes) who could not be corrected within +/- 1.00 D of refractive astigmatism and/or +/- 1.00 D of intended spherical equivalent refraction. In one eye, an interface infiltrate developed shortly after creation of the flap, and resulted in limited melting. CONCLUSIONS: A two-stage LASIK procedure improved visual acuity and refraction in postoperative penetrating keratoplasty eyes with high astigmatism and/or anisometropia. Complications were uncommon but can lead to loss of vision.     

Changes in post-keratoplasty astigmatism after suture removal: refraction vs tomography vs aberrometry

AIM: To analyse the changes in magnitude and orientation of astigmatism after suture removal (SR) in keratoplasty eyes as measured by refraction, tomography, and aberrometry. METHODS: Twenty-six eyes of 25 patients after optical keratoplasty requiring SR to reduce the astigmatism during the follow-up period were prospectively included. Eyes with poor quality topography scans or if there were no sutures in the steepest semi meridian were excluded. Corrected distance visual acuity (CDVA), manifest refraction, corneal tomography and aberrometry were performed on all patients before and after SR. RESULTS: The mean age of the patients was 40.8±14.4y. Penetrating keratoplasty was performed in 23 eyes (89%) and deep anterior lamellar keratoplasty was done in 3 eyes (11%). There was a statistically significant reduction in the magnitude of refractive, tomographic and aberrometry astigmatism after SR (P<0.001) at 2h after suture removal. The mean net reduction of the astigmatism was greater as measured by corneal tomography compared to refractive astigmatism (P<0.05). There was no statistically significant change in refractive astigmatism between 2h and 2mo after SR (P=0.55). Vector calculations demonstrated a greater amount of undercorrection in the tomography group and the rotational error was more towards counterclockwise direction. Mean monocular logMAR CDVA improved from 0.57 D to 0.49 D after SR (P=0.002). CONCLUSION: The net reduction in the magnitude of astigmatism after SR is greater in the tomography and aberrometry groups. With one episode of SR, there is no difference in the aberration profile.     

Surgically-induced astigmatism after laser in situ keratomileusis for spherical myopia

PURPOSE: To characterize the surgically-induced-astigmatism (SIA) associated with spherical LASIK. METHODS: Refractive outcomes in 70 eyes that underwent primary myopic LASIK with purely spherical ablation were analyzed. The Summit Apex Plus excimer laser was used. The Bausch & Lomb Hansatome with the 180-microm plate was used to produce superiorly hinged flaps. The relationship between refractive astigmatism and corneal topographic astigmatism was analyzed using linear regression and vector analysis. RESULTS: There was a statistically significant negative correlation (slope = -0.21) between refractive surgically-induced astigmatism and preoperative topographic cylinder. A 0.24-D with-the-rule shift was also found. Surgically-induced astigmatism was not correlated with the magnitude of laser ablation. CONCLUSION: The lamellar keratotomy portion of LASIK reduces pre-existing corneal astigmatism and produces a relative steepening of the hinge meridian.     

Effect of hinged lamellar keratotomy on postkeratoplasty eyes

PURPOSE: To evaluate the effect of a hinged lamellar keratotomy on refraction, vision, and corneal topography of postkeratoplasty eyes with high-degree astigmatism. DESIGN: Noncomparative, interventional case series. PARTICIPANTS: A hinged lamellar keratotomy was performed on nine eyes of nine patients at least 9 months after penetrating keratoplasty and with high-degree astigmatism. All patients were spectacle and contact lens intolerant. INTERVENTION: A superiorly hinged lamellar keratotomy (corneal flap), 160 microm in thickness and 9 mm in diameter, was created on all eyes included in this study. Each patient was examined 1 day, 1 month, and 3 months after surgery. MAIN OUTCOME MEASURES: Uncorrected visual acuity, best spectacle-corrected visual acuity, refraction, computerized analysis of corneal topography. RESULTS: At each postoperative examination time, there was a significant reduction in both average spherical equivalent (P < 0.05) and average absolute value of astigmatism (P < 0.01) over mean preoperative values. The major changes were seen as early as 1 day after surgery, but both progression and regression of the effect were documented at later postoperative examinations. In all patients best spectacle-corrected acuity was maintained or improved after the procedure. Postoperatively, four patients could be successfully corrected either with spectacles (n = 2) or with gas-permeable contact lenses (n = 2). There were no surgical flap or corneal graft complications. CONCLUSIONS: Hinged lamellar keratotomy improves vision and refraction of postkeratoplasty eyes with high-degree astigmatism. In some cases it may be so effective as to make planned excimer laser treatment unnecessary.     

Refractive outcomes after V4c Toric collamer lens implantation over 1y of follow-up

AIM: To evaluate refractive outcomes and corneal astigmatism changes after Toric implantable collamer lens with a central port (V4c T-ICL) implantation over 1y of follow-up. METHODS: A retrospective study was performed including 50 eyes of 50 patients that underwent V4c T-ICL implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, refractive and corneal astigmatism changes and corneal coupling correction were evaluated preoperatively, 1 and 12mo postoperatively. Vector analysis was used for astigmatism changes. Coefficient of adjustment (CAdj) was calculated for corneal coupling analysis. RESULTS: The mean UDVA achieved was 0.03 logMAR at 1mo and remained unchanged throughout the whole follow-up (P=0.193). At the last visit, 84% of the eyes achieved a CDVA of 0.00 logMAR or better. Regarding spherical equivalent refraction (SEQ), 96% of eyes were ranges of ±1.00 D and 84% of them within ±0.50 D. Also, 94% of eyes had a remaining refractive cylinder within ±1.00 D and 78% of them within ±0.50 D. Both, SEQ and refractive cylinder, remain stable over the postoperative follow-up (P=1.000 and P=0.660, respectively). In terms of surgically induced astigmatism (SIA), no statistically significant differences were found over the follow-up (P=0.102) and under correction was found with a correction index lower than the unit at each visit. A keratometric astigmatism induced of 0.59±0.53 (vector mean: 0.26×73º) D was reached at the last visit. No significant changes in terms of corneal astigmatism orientation were reported over post-surgery visits (P=0.129 and P=0.097 at 1 and 12mo respectively). No clinical significance was found for CAdj on with-the-rule astigmatism. No postoperative complications resulting from the surgery were found. CONCLUSION: Refractive outcomes suggest that the V4c T-ICL implantation for correction of myopic astigmatism was satisfactory in terms of effectiveness, safety, and stability during 1y of follow-up. Corneal astigmatism induced by the incision around 0.5 D is achieved according to the remaining refractive cylinder found at one-year post-surgery. Corneal coupling analysis results in no unexpected spherical change.     

Laser in situ keratomileusis for undercorrection after radial keratotomy.

PURPOSE: To assess the safety and efficacy of excimer laser in situ keratomileusis (LASIK) in treating residual myopia and/or astigmatism following refractive keratotomy. METHODS: Fourteen eyes that had previously undergone radial and/or arcuate keratotomy were included. The surgeries were performed using the Chiron Automated Microkeratome and the VISX 20/20B excimer laser. RESULTS: Average follow-up was 12.64+/-5.02 months. Mean spherical equivalent refraction was reduced from -3.48+/-3.52 D preoperatively to -0.04+/-0.87 D postoperatively. At the last follow-up examination there were 8 eyes (57.1%) with a refraction within+/-0.50 D, and 10 eyes (71.4%) within +/-1.00 D of emmetropia. Uncorrected visual acuity was 20/20 or better in 4 eyes (28.6%) and 20/40 or better in 10 eyes (71.4%). Vector analysis of the astigmatic correction showed an index of success of 80%. There was no significant loss (> or = or =2 lines) of spectacle-corrected visual acuity. We observed interface epithelial ingrowth in one eye. CONCLUSIONS: The correction of residual myopia and/or astigmatism with LASIK in eyes with prior refractive keratotomy proved to be safe and effective. Careful preoperative evaluation may help to avoid complications such as reopening of incisions during surgery or postoperative ingrowth of epithelium beneath the corneal flap.     

Laser in situ keratomileusis for astigmatism ≤ 0.75 Diopter combined with low myopia: a retrospective data analysis

Background

This study examined the refractive and visual outcome of wavefront-optimized laser in situ keratomileusis (LASIK) in eyes with low myopia and compound myopic astigmatism?≤?0.75 diopter (D).

Methods

153 eyes from 153 consecutive myopic patients (74 male, 79 female; mean age at surgery 40.4?±?10.4 years) who had a preoperative refractive cylinder?≤?0.75 D and a manifest sphere between -0.25 D and -2.75 D, and who had completed 4-month follow-up. Three subgroups defined by the magnitude of preoperative manifest refractive cylinder (0.25, 0.50, and 0.75 D) were formed. Manifest refraction, uncorrected and corrected visual acuity were assessed pre- and postoperatively. The astigmatic changes achieved were determined using the Alpins vector analysis.

Results

After 4 months (120.0?±?27.6 days) of follow-up, a mean uncorrected distant visual acuity of 0.07?±?0.11 logMAR and a mean manifest refraction spherical equivalent of -0.06?±?0.56 D were found. There was no statistically significant difference in efficacy and safety between the preoperative cylinder groups. Astigmatic overcorrection for preoperative cylinder of?≤?0.50 D was suggested by the correction index, the magnitude of error, the index of success, and the flattening index.

Conclusions

Low myopic eyes with a preoperative cylinder of?≤?0.50 D were significantly overcorrected with regard to cylinder correction when combined with low myopic LASIK. Accordingly, we are cautious in recommending full astigmatic correction for eyes with low myopia and manifest cylinder of?≤?0.50 D.     

Laser in situ keratomileusis for ametropia after penetrating keratoplasty

PURPOSE: To evaluate the efficacy of excimer laser in situ keratomileusis (LASIK) in the treatment of refractive errors after penetrating keratoplasty. METHODS: Eight eyes underwent LASIK after a mean 71 months (SD 60) following the initial penetrating keratoplasty. A full ophthalmic assessment was performed before LASIK and at 1 week, 1, 3, 6, and 12 months after surgery. Mean follow-up was 8.6 months (SD 3.2). RESULTS: No eyes lost any Snellen lines of best spectacle-corrected visual acuity at the latest follow-up. Mean reduction in spherical equivalent refraction was 91% from -6.79 D (SD 4.17) to -0.64 D (SD 1.92) and mean reduction of cylinder was 72% from -6.79 D (SD 3.28) to -1.93 D (SD 1.17) at 6 months. Mean surgically induced astigmatism was 5.50 D (SD 2.42) and the index of surgically induced astigmatism divided by the initial cylinder expressed as a percentage was 81%. Mean outcome indices were: correction index 0.87, index of success 0.31, and angle of error 0.95 degrees. Three eyes (43%) achieved a spherical equivalent refraction of +/-0.50 D and 4 eyes (57%) achieved a spherical equivalent refraction of +/-1.00 D of emmetropia. CONCLUSIONS: The efficacy of LASIK after penetrating keratoplasty was good compared to incisional or surface based excimer laser methods and has the advantage of reducing the myopic spherical equivalent refraction in addition to astigmatism, thus improving the uncorrected visual acuities.     

Intraoperative arcuate transverse keratotomy with phacoemulsification

PURPOSE: To evaluate the efficacy of paired intraoperative arcuate transverse keratotomy at a 7-mm-diameter zone along with a 3.5-mm clear corneal phaco tunnel in the steeper axis to correct pre-existing astigmatism. METHODS: A prospective randomized case-control study was conducted on 34 eyes of 28 patients with immature senile cataract. They were divided into two groups; in one group (17 eyes) intraoperative arcuate keratotomy was coupled with phacoemulsification in the steeper meridian (arcuate keratotomy group; mean preoperative astigmatism 2.28 +/- 0.89 D) and the other group (17 eyes) phacoemulsification was performed in the steeper meridian without arcuate keratotomy (control group; mean preoperative astigmatism 2.04 +/- 0.50 D). The patients were examined at 1 day, and 1, 4, and 8 weeks postoperatively. Correction of keratometric astigmatism, surgically induced refractive changes, magnitude and axis of cylinder, spherical equivalent refraction, with and against the wound change, and coupling ratio were evaluated. RESULTS: Mean reduction in keratometric astigmatism in the keratotomy group was 1.26 +/- 0.54 D (P = .0067) and in the control group was 0.48 +/- 0.60 D (P = .0423). The difference in reduction of keratometric astigmatism between the two groups was statistically significant (P = .0296). Surgically induced refractive change at 8 weeks follow-up was 2.15 +/- 1.13 D in the keratotomy group and 1.50 +/- 1.32 D in the control group (P = .046). Coupling ratio was -1.10 +/- 0.43 in the keratotomy group at 8 weeks after surgery while the control group was -0.82 +/- 0.38. CONCLUSION: A combination of intraoperative arcuate keratotomy with steep axis phacoemulsification incision is more effective than steep axis phacoemulsification incision alone in reducing pre-existing astigmatism.     

Surgical correction of postkeratoplastyastigmatism with the Hanna arcitome

Purpose:To report the results of arcuate keratotomy performed with the Hannaarcitome in patients with postkeratoplasty astigmatism.Setting:Department of Ophthalmology, Saint-Antoine Hospital, Paris VI University, Paris, France.Methods:This retrospective study comprised 22 eyes (22 patients) with postkeratoplasty astigmatism. Paired symmetrical arcuate keratotomy was performed with the Hanna arcitome. Outcome measures included refraction, videokeratography, and keratometry.Results:At 6.6 months ± 8.9 (SD) after surgery, the mean increase in best spectacle-corrected visual acuity (BSCVA) was 2.1 ± 2.4 lines. Thirteen eyes gained 2 lines or more of BSCVA, and 15 gained 3 lines or more of uncorrected visual acuity. Two patients had a decrease in BSCVA: 1 had lens opacification unrelated to arcuate keratotomy and 1, increased corneal irregularity. Mean refractive astigmatism was 6.94 ± 2.11 diopters (D) preoperatively and 3.85 ± 1.95 D postoperatively (P < .01). Mean change in keratomeric astigmatism was −51 ± 36%. Astigmatism decreased in 21 eyes as measured by manifest refraction, keratometry, and videokeratography; it increased in 1 cornea with a microperforation.Conclusions:The results of arcuate keratotomy performed with the Hanna arcitome were comparable to those with freehand relaxing incisions. The instrument made safer and more uniform arcuate incisions than a freehand technique.     

Laser in situ keratomileusis to correct post-keratoplasty astigmatism; 1-step versus 2-step procedure

PURPOSE: To investigate the correction of post-penetrating keratoplasty (PKP) astigmatism using laser in situ keratomileusis (LASIK). Visual and refractive outcomes were evaluated after LASIK was performed in 1 step (lamellar cut and ablation in 1 procedure) or 2 steps (lamellar cut then ablation in 2 successive procedures). SETTING: Department of Cornea and Refractive Surgery, Vissum-Instituto Oftalmológico de Alicante, University of Miguel Hernández, Alicante, Spain. METHODS: In this prospective observational study, 22 consecutive eyes were divided into 2 groups depending on the LASIK procedure performed to correct post-PKP astigmatism. Group 1 (1-step LASIK) included 11 eyes and Group 2 (2-step LASIK), 11 eyes. The patients were followed for 6 months. RESULTS: A statistically significant improvement was obtained in Group 2 with a mean vector analysis result of the cylinder of -4.37 diopters (D) +/- 1.79 (SD) (P = .018). In Group 1, the mean astigmatism correction was 2.38 +/- 1.71 D. The number of reoperations and residual refractive defects were significantly better in Group 2. CONCLUSION: The 2-step technique improved the accuracy of excimer laser correction of post-PKP astigmatism.     

Conductive keratoplasty for symptomatic presbyopia following monofocal intraocular lens implantation

Background: To evaluate the visual outcomes of conductive keratoplasty for relief of symptomatic presbyopia of pseudophakia with monofocal intraocular lens implantation. Design: It was a prospective clinical study and set in Eye Center, Second Affiliated Hospital, Zhejiang University. Participants: This study comprised 27 eyes from 27 patients with presbyopia symptom. Methods: The patients received conductive keratoplasty via monovision approach after monofocal intraocular lens implantation and were followed up at 1 week and 1, 3, 6 and 12 months postoperatively. Main Outcome Measures: The main outcomes including uncorrected near visual acuity, uncorrected distance visual acuity, best spectacle‐corrected visual acuity, manifest refraction spherical equivalent, keratometric astigmatism, contrast and glare sensitivity, spherical aberration and pseudoaccommodation were evaluated. Results: Twelve months after conductive keratoplasty, the binocular uncorrected near visual acuity was significantly improved from logMAR 0.88 ± 0.16 preoperatively to logMAR 0.30 ± 0.13 (P < 0.05); the binocular uncorrected distance visual acuity and best spectacle‐corrected visual acuity remained unchanged; manifest refraction spherical equivalent was significantly reduced from 0.01 ± 0.68 D preoperatively to ?1.68 ± 0.39 D (P < 0.05); spherical aberration was increased from 0.266 ± 0.204 µm preoperatively to 0.358 ± 0.277 µm (P < 0.05), and pseudoaccommodation was from 1.38 ± 0.38 D to 1.73 ± 0.61 D (P < 0.05). Conclusions: Conductive keratoplasty is a safe and effective method for relief of symptomatic presbyopia of pseudophakia with monofocal intraocular lens implantation.     

Laser in situ keratomileusis for residual hyperopic astigmatism after conductive keratoplasty

PURPOSE: To report a case of laser in situ keratomileusis (LASIK) in a patient with previous conductive keratoplasty. METHODS: A 48-year-old man underwent conductive keratoplasty for low hyperopic astigmatism (manifest refraction OD: +2.25 -0.50 x 77 degrees; OS: +2.50 -0.50 x 105 degrees). Three months postoperatively, UCVA was 20/25 and BSCVA was 20/20 in both eyes; manifest refraction OD: -0.25 -0.75 x 110 degrees; OS: +0.75 -0.75 x 50 degrees. Sixteen months after the operation, regression of refractive outcome was (manifest) OD: +1.75 -1.25 x 90 degrees; OS: +2.50 -0.50 x 85 degrees; UCVA was 20/40 in the right eye and 20/63 in the left eye and BSCVA was 20/20 in both eyes. LASIK was performed for hyperopic regression in the left eye using an automated microkeratome (Alcon SKBM, 130-microm plate; Aesculap-Meditec MEL 70 excimer laser). RESULTS: LASIK was uneventful and no intraoperative or postoperative complications related to the previous conductive keratoplasty procedure or LASIK were observed. Three months after LASIK and 19 months after the initial conductive keratoplasty, the patient's left eye was emmetropic; UCVA was 20/20(-2), BSCVA was 20/20 and manifest refraction was +0.25 -0.25 x 35 degrees. There was a uniform increase in topographical steepening. Visual acuity, refraction and topographic findings remained unchanged at 6 months. CONCLUSIONS: Even though our experience is limited, treatment of hyperopia with LASIK in an eye with refractive regression following previous conductive keratoplasty resulted in a predicted refractive outcome, with no complications, and improvement in visual acuity at 6 months follow-up.     

Arcuate keratotomy for asymmetrical steep islands after laser in situ keratomileusis and automated lamellar keratoplasty

PURPOSE: To determine the safety and efficacy of arcuate keratotomy (AK) to reduce or eliminate steep asymmetrical islands after laser in situ keratomileusis (LASIK) and automated lamellar keratoplasty (ALK). SETTING: Rancho Bernardo Laser and Vision Center, San Diego, California, USA. METHODS: This retrospective and noncomparative interventional study comprised 8 eyes of 5 patients who received arcuate incisions to reduce topographically defined asymmetrical steep islands after LASIK (n = 7) and ALK for hyperopia (n = 1). The islands occurred unexpectedly after standard excimer laser treatment (VISX Star and S2) for myopic astigmatism that induced irregular astigmatism and unwanted optical effects. Cases occurred consecutively over 16 months, an incidence of less than 1%. Arcuate incisions extended 30 or 45 degrees in LASIK eyes based on the amount of residual refractive astigmatism and were placed at 7.0 mm on the steep axis. Radial incisions were limbal sparing to a 5.0 mm optical zone following the Casebeer nomogram. Outcome measures were uniformity of postenhancement topography, uncorrected visual acuity (UCVA), postenhancement refraction, and reduction in unwanted optical effects. RESULTS: The preenhancement mean spherical equivalent (SE) in the LASIK eyes was -0.99 diopters (D) +/- 0.48 (SD); the astigmatism ranged from 0.50 to 1.75 D. After incisional keratotomy, the mean SE was -0.21 +/- 0.12 D and the net residual astigmatism was reduced to a range of 0 to 0.75 D. All 8 eyes had AK to reduce topographically defined steep islands that were causing visual blurring and unwanted optical effects including ghosting, halos, and polyplopia. After enhancement, there was a marked reduction in the asymmetrical steep islands by topography, fewer unwanted optical effects, less refractive astigmatism, and improved UCVA. Two patients retained small inferior steep areas that may indicate forme fruste keratoconus, although this condition was not detected preoperatively by topographical indices. CONCLUSION: Uncorrected visual acuity improved and unwanted optical effects were reduced after AK on the peripheral axis of asymmetrical steep islands that occurred after uneventful LASIK and hyperopic ALK. This relatively simple incisional approach may be used until more advanced topography-linked ablations with rapid and precise eye tracking are perfected and widely available.     

Comparison of visual acuity, refractive results and complications of femtosecond laser with mechanical microkeratome in LASIK

AIM:To compare the outcomes of laser in situ keratomileusis (LASIK) performed with a femtosecond laser (Femtec, Technolas Perfect Vision GmbH, Germany) versus a mechanical microkeratome (Hansatome, Bausch and Lomb, USA) for the correction of myopia and astigmatism.METHODS: In this retrospective study, patients who had undergone LASIK using the 80-kHz Femtec femtosecond laser were compared to age- and refraction-matched patients in whom the Hansatome microkeratome was used. Refractive and visual results 1 month and 3 months postoperatively, and complication rates were compared between the two groups.RESULTS:A total of 280 eyes were analyzed (140 in each group).At 3 months postoperatively in the Femtec vs Hansatome group, spherical equivalent refraction was within ±1.00D of emmetropia in 140 vs 138 eyes (P=0.498), the cylinder was within ±0.50D in 137 vs 139 eyes (P=0.622), and the UDVA was 20/20 or better in 136 vs 137 eyes (P=0.724), respectively. There was no statistically significant difference in the complication rates between the two groups (P=0.099).CONCLUSION:LASIK performed both with Femtec femtosecond laser and Hansatome microkeratome achieved satisfactory refractive and visual results at 3 months postoperatively, without significant differences in efficacy, safety, and complication rates between the two procedures.     

Laser in situ keratomileusis for correction of high astigmatism after penetrating keratoplasty

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) for correction of high astigmatism after penetrating keratoplasty, and to assess the refractive results and predictability of the procedure. METHODS: LASIK was performed on 19 patients (19 eyes) with high astigmatism after penetrating keratoplasty, using the Chiron Automated Corneal Shaper and the Chiron-Technolas Keracor 116 excimer laser. The amount of preoperative refractive astigmatism ranged from 6.50 to 14.50 D (mean, 9.21 +/- 1.95 D) and the spherical component of manifest refraction ranged from -7.00 to +1.25 D (mean, -2.14 +/- 2.11 D). All patients completed a minimum follow-up of 12 months. RESULTS: Refraction was stable after 3 months. At 1 year after LASIK, the amount of refractive astigmatism was reduced to a mean of 1.09 +/- 0.33 D (range, 0.50 to 1.75 D), with 57.9% of the eyes within +/- 1.00 D of refractive astigmatism. The mean percent reduction of astigmatism was 87.9 +/- 3.7%. The postoperative spherical component of manifest refraction ranged from -1.00 to +1.75 D with a mean of +0.43 +/- 0.82 D. Vector analysis showed that the mean amount of axis deviation was 1.1 +/- 1.3 degrees and the mean percent correction of preoperative astigmatism was 92.6 +/- 8.4%. There were no intraoperative complications. Spectacle-corrected visual acuity was not reduced in any eye, and improved by 2 or more lines in 42.1% of eyes after LASIK. CONCLUSION: LASIK with the Chiron-Technolas Keracor 116 excimer laser was effective for correction of both astigmatism and myopia after penetrating keratoplasty. The procedure proved to be safe and gave fairly predictable and stable refractive results.     

Astigmatic keratotomy for post-keratoplasty astigmatism

PURPOSE: To assess astigmatic keratotomy as a means of managing post-keratoplasty astigmatism in the era of excimer laser refractive surgery. SETTING: Moorfields Eye Hospital, London, England. METHODS: Fifty paired arcuate keratotomies were performed with refractive and topographic guidance. Refraction, uncorrected visual acuity, best corrected visual acuity, and visual acuity with the patient's preferred correction were measured before and after surgery. RESULTS: The median follow-up was 34 months. The mean cylinder was 9.13 diopters (D) preoperatively and 4.85 D postoperatively. The mean spherical equivalent refraction was -4.21 D preoperatively and -4.26 D postoperatively. The amount of cylinder reduction was correlated with the amount of pre-existing cylinder (P<.001). Thirty eyes (60%) gained and 1 eye (2%) lost Snellen acuity with preferred correction. In the remaining 19 eyes (38%), there was no change in acuity with preferred correction. The mean change in visual acuity with preferred correction was a gain of 1.5 Snellen lines. Three patients intolerant of spectacles or contact lenses before surgery became tolerant. Ten patients (20%) previously unsuitable for laser in situ keratomileusis (LASIK) because of high cylindrical error went on to have LASIK. CONCLUSIONS: Astigmatic keratotomy remains a useful, safe, relatively simple surgical procedure for treating post-keratoplasty astigmatism. Reduction in cylinder was correlated with pre-existing cylinder. Vision with preferred correction was improved in 60% of cases. High astigmatism reduced to a level at which more definitive refractive surgery such as LASIK became feasible.     

Descemet’s stripping automated endothelial keratoplasty and penetrating keratoplasty for Fuchs’ endothelial dystrophy

Purpose: To compare the outcome of Descemet’s stripping endothelial keratoplasty (DSAEK) to that of penetrating keratoplasty (PK) in patients with Fuchs’ endothelial dystrophy. Methods: The first 20 patients who underwent DSAEK at the Department of Ophthalmology, Aarhus University Hospital were compared to 20 patients treated with classic PK. Best‐corrected visual acuity, subjective spectacle refraction and corneal thickness were registered before surgery and 1, 3, 6 and 12 months after DSAEK surgery; they were also measured before surgery and 12 months and 2–3 years after PK. Endothelial cell density was measured 12 months after surgery in both groups. Results: Two primary graft failures were observed in the DSAEK group; no failures were seen in the PK group. Best spectacle‐corrected visual acuity (BSCVA) at 12 months after surgery was significantly better in the DSAEK group (0.56 ± 0.04) than in the PK group (0.33 ± 0.06). At this time, 70% of the DSAEK‐treated eyes but only 25% of PK‐treated eyes had obtained a BSCVA of 0.5 or better. Two to three years after surgery, BSCVA was 0.5 or better in 55% of PK‐treated eyes. Refractive ametropia and astigmatism were significantly smaller in DSAEK‐treated eyes than in PK‐treated eyes, even after suture removal and arcuate keratotomy. Endothelial cell density (cells/mm²) after 1 year was lower in DSAEK‐treated (1.338 ± 113) than in PK‐treated eyes (1.610 ± 124), but the difference was not statistically significant. Conclusion: DSAEK seems to be superior to PK in treating Fuchs’ endothelial keratoplasty, although primary graft failure may be more common. Visual recovery is faster, and major ametropia and astigmatism is not induced. Long‐term follow‐up studies are essential to assess whether this conclusion also holds true more than 1 year after surgery.