Topography-guided LASIK Research Articles

Retrospective Study Comparing Topography-Guided and Wavefront-Optimized LASIK Procedures in a Single Center.

To compare visual outcomes of eyes that had laser refractive surgery with the Contoura Phorcides treatment plan and eyes that had laser refractive surgery with the wavefront-optimized treatment plan using the same laser. Retrospective chart review of clinical outcomes of eyes that had either Contoura with Phorcides (CP) or wavefront-optimized (WFO) corneal refractive procedures using the Wavelight EX500 (Alcon Vision, LLC). Data were collected and compared for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, change in postoperative UDVA compared to preoperative CDVA, and change in postoperative CDVA compared to preoperative CDVA. Total eyes included were 348, with 227 in the CP Group and 121 in the WFO Group. Post-operatively, there was a significantly higher percentage of eyes in the CP Group that were 20/16 or better compared to the WFO Group (57%, 129 eyes, and 17%, 21 eyes, respectively; p < 0.001). The percentage of eyes that gained 1 or more Snellen lines of UDVA compared to preoperative CDVA was higher in the CP Group (47%; 107 eyes) compared to the WFO Group (12%; 14 eyes), which was statistically significant (p < 0.001). Differences in refraction were statistically significant. Topography-guided and wavefront-optimized treatment profiles both provided excellent refractive results. A higher percentage of eyes that were treated using Contoura with Phorcides achieved 20/16 or better unaided distance vision compared to eyes receiving a wavefront-optimized treatment plan.

Clinical outcomes of topography-guided versus wavefront-optimized LASIK for correction of myopia and compound myopic astigmatism.

To compare the safety, efficacy, and visual outcomes of topography-guided (TG) LASIK ablation versus advanced ablation algorithm (AAA) on Zeiss Mel 90 on virgin eyes. A tertiary care hospital in north India. A retrospective comparative study. Case sheets of 30 patients who underwent TG LASIK and 45 patients who underwent AAA LASIK between January 2021 and September 2022 were retrieved and reviewed. The TG group included 60 eyes of 30 patients, and the AAA group included age- and sex-matched 90 eyes of 45 patients. Both groups were compared for visual outcomes, residual refraction, and root-mean-square higher-order aberrations (rms HOA) at 1 week, 1 month, 3 months, and 6 months postoperatively and using unpaired t-test and Mann-Whitney U test. The mean preoperative spherical equivalent in the TG group and AAA group was - 3.12 (1.67) and - 3.19 (1.61), respectively. The safety and efficacy of the treatment were 100% in both groups. The postoperative increase in rms HOA was comparable in both groups (P = 0.55). The ablation duration was significantly longer in topo-guided LASIK (P = 0.001). AAA LASIK on MEL 90 is comparable to topography-guided LASIK for the management of low myopia and myopic astigmatism.

Comparison of Corneal Higher-Order Aberrations Following Topography-Guided LASIK and SMILE for Myopic Correction: A Propensity Score Matching Analysis.

Ocular aberrations, particularly corneal higher-order aberrations (HOAs), which impair visual quality, should be minimized or corrected during any laser vision correction. We compared changes in visual outcomes, including HOAs, in patients who underwent Topography-Guided laser-assisted in situ keratomileusis (TG-LASIK) or small-incision lenticule extraction (SMILE) after propensity score matching (PSM) to reduce selection bias. Of 2749 patients who underwent SMILE or TG-LASIK for myopia, 152 eyes underwent complete ophthalmic examination preoperatively and over six months postoperatively. Visual outcomes were comparatively analyzed after PSM. As a result, 45 eyes were included in each group after PSM. There was a comparable improvement in visual acuity (VA) and refractive parameters postoperatively, with no difference between the two PSM-groups. However, 6.6% in the SMILE PSM-group lost two or more lines of Snellen VA at the six-month follow-up, while none in the TG-LASIK PSM-group did. Specifically, the SMILE PSM-group showed a significant increase in corneal HOAs, including spherical aberration, coma, and total HOAs (0.0736 ± 0.162 μm; 0.181 ± 0.233 μm; and 0.151 ± 0.178 μm, respectively), whereas TG-LASIK PSM-group did not. Furthermore, SMILE PSM-group had greater postoperative corneal HOAs than those in TG-LASIK PSM-group. Collectively, TG-LASIK induces fewer corneal HOAs even after facilitating between-group comparability using PSM analysis. TG-LASIK provides better visual quality than SMILE for myopia.

Comparison of Corneal Optical Quality After SMILE, Wavefront-Optimized LASIK and Topography-Guided LASIK for Myopia and Myopic Astigmatism.

PurposeTo compare visual outcomes and corneal optical quality after small incision lenticule extraction (SMILE), wavefront-optimized (WFO) FS-LASIK, and topography-guided customized ablation treatment (TCAT) FS-LASIK for myopia.MethodsThis prospective case-series study included 283 eyes of 283 myopic patients who underwent SMILE or FS-LASIK. There were 102, 100, and 81 eyes in the SMILE group, WFO group and TCAT group, respectively. The tomography system (Sirius) was used to measure corneal aberrations and optical quality.ResultsAt postoperative 1 and 6 months, there were no significant differences in uncorrected distance visual acuity and corrected distance visual acuity among the three groups (P > 0.05). Postoperative manifest refractive spherical equivalent was similar among the groups (P > 0.05). There was statistically significant difference in cylinder at 1 month among the three groups, with the highest mean value in TCAT group (P < 0.05). The corneal optical path difference, root mean square of corneal astigmatism and strehl ratio were the most superior in the TCAT group at postoperative 1 and 6 months (P < 0.05).ConclusionSMILE, WFO FS-LASIK, and TCAT FS-LASIK provided similar visual results. The corneal visual quality after TCAT FS-LASIK was the best.

Guidelines and Clinical Pearls for Laser Vision Correction

LASIK and PRK are well established procedures for the correction of myopia, hyperopia, and astigmatism. The percentage of ophthalmologists and optometrists that have undergone these procedures is higher than in the general population. The clinical goal is to continue to advance the technology and techniques to improve outcomes. The newest and considered the most advanced custom vision correction is Topography-guided LASIK and Topography-guided PRK using advanced analytics software. Topographic corneal imaging is used to measure over 20,000 data points, and this curvature information is used to guide the excimer laser to reduce irregularity of the corneal surface and treat the refractive error. In addition, the excimer laser ablation is centered on the line of sight versus the center of the pupil, and there is iris registration to account for cyclotorsion. CE Notification: This article is available as a COPE accredited CE course. You may take this course for 1-hour credit. Read the article and take the qualifying test to earn your credit. Click here to Enroll (https://www.crojournal.com/guidelines-and-clinical-pearls-for-laser-vision-correction)

Vector Analysis Reveals That Topography-Guided LASIK Targeting the Manifest Refraction (MR) is Superior to Topography-Modified Refraction (TMR) and Layer Yolked Reduction of Astigmatism (LYRA) [Response to Letter

Vector Analysis Reveals That Topography-Guided LASIK Targeting the Manifest Refraction (MR) is Superior to Topography-Modified Refraction (TMR) and Layer Yolked Reduction of Astigmatism (LYRA) [Response to Letter

Vector Analysis Reveals That Topography-Guided LASIK Targeting the Manifest Refraction (MR) is Superior to Topography-Modified Refraction (TMR) and Layer Yolked Reduction of Astigmatism (LYRA) [Letter

Vector Analysis Reveals That Topography-Guided LASIK Targeting the Manifest Refraction (MR) is Superior to Topography-Modified Refraction (TMR) and Layer Yolked Reduction of Astigmatism (LYRA) [Letter

&lt;p&gt;Clinical Outcomes After Topography-Guided Refractive Surgery in Eyes with Myopia and Astigmatism – Comparing Results with New Planning Software to Those Obtained Using the Manifest Refraction&lt;/p&gt;

PurposeTo compare clinical outcomes from topography-guided laser refractive surgery based on new planning software to outcomes based on using the manifest refraction.DesignSingle site, two-arm, retrospective chart review.MethodsClinical outcomes at a single site after topography-guided LASIK using the Wavelight excimer laser were evaluated, with a target postoperative follow-up time of 90 days. Eligible eyes were those that received on-label topography-guided treatment of myopia or myopic astigmatism with correction based on either the manifest refraction or results from the Phorcides Analytical Engine (PAE). Measures analyzed included the uncorrected (UDVA) and best-corrected (CDVA) distance visual acuity, the magnitude of refractive cylinder after surgery, the refractive error and changes from preoperative CDVA.ResultsThe study included 115 eyes in the PAE group and 133 eyes in the Manifest group. Significantly more eyes in the PAE group had a CDVA of 20/15 or better (p = 0.05) and a UDVA of 20/15 or better (p = 0.05). Significantly more eyes in the Manifest group had a UDVA of 20/25 or worse (13/133 vs 1/115 in the PAE group, p = 0.002). There were significantly more eyes in the PAE group with no postoperative refractive cylinder (90% vs 77% in the Manifest group, p = 0.004). No eye in either group had a postoperative CDVA a line or worse than their preoperative CDVA. Three eyes in the Manifest group and no PAE eyes have had subsequent enhancement surgery.ConclusionMean results for postoperative refractive astigmatism, CDVA and UDVA were similar between the groups, but the clinical outcomes for the PAE group appeared less variable, with more eyes having no refractive astigmatism and a higher percentage of eyes having 20/15 or better CDVA and UCVA. The objective nature of the PAE is an advantage.

Management of interface irregularity due to high energy after uneventful SMILE

A 48-year-old man was referred for the management of suboptimal vision after an uneventful bilateral small-incision lenticule extraction (SMILE) procedure, performed 6 weeks previously. His corrected distance visual acuity (CDVA) was 6/9p and 6/12 in the right eye and the left eye, respectively. Corneal topography was regular, and higher-order aberrations were within the acceptable range. Clinical photographs in retroillumination revealed rough and irregular interface in both eyes, probably because of the use of a relatively high-energy cut index of 40 (200 nJ) to perform SMILE. The case was managed by CIRCLE software–enabled flap creation with phototherapeutic keratectomy (PTK), followed by enhancement with flap relift and topography-guided LASIK 3 months later in both eyes, which resulted in improvement in the CDVA to 6/4.5 in the right eye and 6/9p in the left eye. CIRCLE software–enabled flap creation and PTK might result in satisfactory visual outcomes in cases of interface irregularity after SMILE.

Comparison of outcomes after topography-modified refraction versus wavefront-optimized versus manifest topography-guided LASIK

BackgroundTo compare the outcomes of myopia and myopic astigmatism corrected with topography-modified refraction laser in situ keratomileusis (TMR-LASIK), wavefront-optimized (WFO) LASIK, and topography-guided (TG) LASIK with a correction target based on the manifest refraction (manifest TG-LASIK).MethodsThis observational, retrospective cohort study included patients who underwent LASIK using the WaveLight® EX500 excimer laser to correct myopia and myopic astigmatism between August 2016 and July 2017. Patients who underwent TMR-LASIK (85 patients), WFO-LASIK (70 patients), or manifest TG-LASIK (40 patients) were enrolled, and only one eye from each patient was analyzed. All participants underwent measurement of the uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (BCVA), manifest refraction, vector analysis of astigmatic change, corneal topography, and corneal wavefront analysis at baseline and at every posttreatment visit.ResultsThree months postoperatively, a UDVA of 0.0 logMAR or better and manifest refraction spherical equivalent (MRSE) within ±0.5 diopters (D) did not differ across the TMR-, WFO-, and manifest TG-LASIK groups. However, the residual cylinder in the TMR group was significantly larger than that in the WFO and manifest TG groups. The magnitude of error in the TMR group measured using astigmatism vector analysis was significantly higher than that in the WFO and manifest TG groups.ConclusionsAlthough these three LASIK platforms achieved the predicted surgical outcomes, TMR-LASIK overcorrected astigmatism and showed a higher residual postoperative astigmatism compared with WFO- and manifest TG-LASIK.

Topography-Guided Refractive Astigmatism Outcomes: Predictions Comparing Three Different Programming Methods.

PurposeTo identify the laser programming strategy that will achieve optimal refractive outcomes of LASIK with a topography-guided laser for eyes with a disparity between cylinder measured by manifest refraction and cylinder measured by topography.SettingSix surgeons at 5 clinical sites in the USA.DesignRetrospective data review.MethodsPreoperative, treatment, and postoperative data on 52 eyes that underwent topography-guided LASIK with the WaveLight EX500 Contoura® Vision excimer laser ablation profile in which the vectors representing the preoperative refractive cylinder and the cylinder measured by the WaveLight® Topolyzer™ VARIO Diagnostic Device (Vario cylinder) differed by >/= 0.50D and/or >/= 10 degrees of orientation were analyzed retrospectively. Data were contributed by six surgeons using the laser at 5 different clinical sites. Vector analysis of postoperative cylindrical refractive error and the actual laser programming strategy was used to calculate the cylindrical correction that would, theoretically, have completely eliminated postoperative refractive cylinder. This was compared to expected results using the preoperative manifest cylinder, the topographic cylinder, and the Phorcides Analytic Engine (Phorcides LLC, North Oaks MN; Phorcides). For analysis, subjects were stratified on the basis of the vector difference between Manifest and Topo cylinder (High, >0.75 D; and Low, ≤0.75 D).ResultsThe poorest calculated theoretical outcomes were obtained with the manifest refraction (centroid: −0.43, 0.22; mean calculated error vector: 0.56 ± 0.42 D; p=ns). Better outcomes were obtained with the topographically measured refraction (centroid: 0.37, 0.02; mean calculated error vector: 0.47 ± 0.33 D; p=ns). The best outcomes were obtained with Phorcides (centroid: −0.15, 0.06; mean calculated error vector: 0.39 ± 0.28 D; p=ns). The mean error vector magnitude in the Phorcides Low group was significantly lower than for the Manifest and Topo Low groups (0.26 D vs 0.48 D and 0.33 D; p<0.01). The mean error magnitude in the Phorcides High group was nearly 0.25 D lower than for the Manifest High group (0.48 D vs 0.70 D; p<0.01), but was the same as for the Topo High group (0.48 D vs 0.48 D).ConclusionOur study suggests that using the topographically measured cylinder or the cylinder selected by Phorcides will produce more desirable refractive outcomes than entry of the preoperative refractive cylinder as the basis for correction of myopia and myopic astigmatism with the WaveLight Contoura Vision excimer laser.

Topography-Guided LASIK versus Small Incision Lenticule Extraction: Long-term Refractive and Quality of Vision Outcomes

Topography-Guided LASIK versus Small Incision Lenticule Extraction: Long-term Refractive and Quality of Vision Outcomes

Topography-modified refraction: adjustment of treated cylinder amount and axis to the topography versus standard clinical refraction in myopic topography-guided LASIK.

Topography-modified refraction: adjustment of treated cylinder amount and axis to the topography versus standard clinical refraction in myopic topography-guided LASIK.

Topography-Guided LASIK Versus Small Incision Lenticule Extraction (SMILE) for Myopia and Myopic Astigmatism: A Randomized, Prospective, Contralateral Eye Study.

To compare safety and efficacy of topography-guided LASIK and contralateral eye SMILE for myopia and myopic astigmatism correction. This prospective, randomized contralateral eye study included 44 eyes of 22 patients with bilateral myopia or myopic astigmatism. Treated eyes were divided into two groups: 22 eyes were treated with topography-guided LASIK and the fellow eye of each patient was treated with SMILE. The following parameters were evaluated preoperatively and up to 3 months postoperatively: uncorrected distance vision acuity (UDVA), corrected distance vision acuity (CDVA), refractive error, corneal keratometry, contrast sensitivity, and Objective Scatter Index. At 3 months, 86.4% of the LASIK group and 68.2% of the SMILE group had UDVA of 20/20 (P < .002) and 59.1% and 31.8%, respectively, had UDVA of 20/16 (P < .002). Spherical equivalent refraction (±0.50 D) was 95.5% for the LASIK group and 77.3% for the SMILE group (P < .002). Residual refraction cylinder (≤ 0.25 D) was 81.8% for the LASIK group and 50% for the SMILE group (P < .001). Contrast sensitivity (6 cycles/degree) was 7.2 ± 1.01 in the LASIK group and 6.20 ± 1.52 in the SMILE group. Objective Scatter Index measurements at 3 months were 1.35 in the LASIK group and 1.42 in the SMILE group. Topography-guided LASIK was superior in all visual performance parameters studied, both subjective and objective. The main difference between the two techniques likely derives from the eye tracking, cyclorotation compensation, and active centration control in the LASIK technology studied in contrast to the current technology available with SMILE-like procedures. This difference appears to affect refractive and visual aberration performance outcomes. [J Refract Surg. 2017;33(5):306-312.].

Topography-modified refraction (TMR): adjustment of treated cylinder amount and axis to the topography versus standard clinical refraction in myopic topography-guided LASIK.

PurposeTo evaluate the safety, efficacy, and contralateral eye comparison of topography-guided myopic LASIK with two different refraction treatment strategies.SettingPrivate clinical ophthalmology practice.Patients and methodsA total of 100 eyes (50 patients) in consecutive cases of myopic topography-guided LASIK procedures with the same refractive platform (FS200 femtosecond and EX500 excimer lasers) were randomized for treatment as follows: one eye with the standard clinical refraction (group A) and the contralateral eye with the topographic astigmatic power and axis (topography-modified treatment refraction; group B). All cases were evaluated pre- and post-operatively for the following parameters: refractive error, best corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), topography (Placido-disk based) and tomography (Scheimpflug-image based), wavefront analysis, pupillometry, and contrast sensitivity. Follow-up visits were conducted for at least 12 months.ResultsMean refractive error was −5.5 D of myopia and −1.75 D of astigmatism. In group A versus group B, respectively, the average UDVA improved from 20/200 to 20/20 versus 20/16; post-operative CDVA was 20/20 and 20/13.5; 1 line of vision gained was 27.8% and 55.6%; and 2 lines of vision gained was 5.6% and 11.1%. In group A, 27.8% of eyes had over −0.50 diopters of residual refractive astigmatism, in comparison to 11.7% in group B (P<0.01). The residual percentages in both groups were measured with refractive astigmatism of more than −0.5 diopters.ConclusionTopography-modified refraction (TMR): topographic adjustment of the amount and axis of astigmatism treated, when different from the clinical refraction, may offer superior outcomes in topography-guided myopic LASIK. These findings may change the current clinical paradigm of the optimal subjective refraction utilized in laser vision correction.

Very High Fluence Collagen Cross-linking as a Refractive Enhancement of a Regressed Previous Astigmatic Keratotomy

To report a novel application of collagen cross-linking (CXL) in refractive astigmatic enhancement of previously performed astigmatic keratotomy. A 28-year-old woman with prior history of bioptics correction of high myopic astigmatism with femtosecond laser-assisted astigmatic keratotomy followed by topography-guided LASIK showed long-term regression of the astigmatism 4 years later. A novel CXL application was employed in an attempt to reverse the regression of the astigmatic keratotomy. The high fluence CXL intervention resulted in correction of 2 diopters of topographic and refractive cylinder. Uncorrected distance visual acuity changed from 20/50 to 20/20 and refraction from -0.50 -2.00 @ 90 to +0.25 -0.25 @ 90 at the 7-month follow-up. A possible novel application of high fluence CXL with refractive cornea effect is introduced. It may offer rapid and simple rehabilitation and its effect may be tapered.

Topography-guided Hyperopic LASIK With and Without High Irradiance Collagen Cross-linking: Initial Comparative Clinical Findings in a Contralateral Eye Study of 34 Consecutive Patients

To evaluate the safety and efficacy of intrastromally applied collagen cross-linking (CXL) in a comparative contralateral eye study of topography-guided femtosecond laser-assisted hyperopic LASIK. Thirty-four consecutive patients with hyperopia and hyperopic astigmatism elected to have bilateral topography-guided LASIK and were randomized to receive a single drop of 0.1% sodium phosphate riboflavin solution under the flap followed by 3-minute exposure of 10 mW/cm2 ultraviolet A (UVA) light with the flap realigned in one eye (CXL group) and no intrastromal CXL in the contralateral eye (no CXL group). All eyes were treated with the WaveLight FS200 femtosecond laser and WaveLight EX500 excimer laser (Alcon Laboratories Inc). Refractive error and keratometric, topographic, and tomographic measurements were evaluated over mean follow-up of 23 months. Preoperatively, mean spherical equivalent refraction was +3.15 +/- 1.46 diopters (D) and +3.40 +/- 1.78 D with a mean cylinder of 1.20 +/- 1.18 D and 1.40 +/- 1.80 D and mean uncorrected distance visual acuity (UDVA) (decimal) of 0.1 +/- 0.26 and 0.1 +/-0.25 in the CXL and no CXL groups, respectively. At 2 years postoperatively, mean spherical equivalent refraction was -0.20 +/- 0.56 D and +0.20 +/- 0.40 D with mean cylinder of 0.65 +/- 0.56 D and 0.76 +/- 0.72 D and mean UDVA of 0.95 +/- 0.15 and 0.85 +/- 0.23 in the CXL and no CXL groups, respectively. Eyes with CXL demonstrated a mean regression from treatment of +0.22 +/- 0.31 D, whereas eyes without CXL showed a statistically significant greater regression of +0.72 +/- 0.19 D (P = .0001). Topography-guided hyperopic LASIK with or without intrastromal CXL is safe and effective, with greater long-term efficacy (less regression) in eyes with CXL. Our data suggest that the regression seen with hyperopic LASIK may be related to biomechanical changes in corneal shape over time.

Outcomes After Topography-Based LASIK and LASEK with the WaveLight Oculyzer and Topolyzer Platforms

To explore the efficacy, safety, and predictability of topography-guided laser epithelial keratomileusis (LASEK) and LASIK treatments using the ALLEGRO Oculyzer (rotating Scheimpflug image-based) as compared to the ALLEGRO Topolyzer (Placido disk-based) platform (WaveLight AG). In this retrospective, non-comparative case series, 72 eyes were treated using Oculyzer data and 71 eyes were treated using Topolyzer data. Seventy-nine men and 64 women ranging in age from 21 to 63 years were included in the study. The 6-month postoperative uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA) of patients were compared to the preoperative values. The data analysis was stratified based on the preoperative refractions, separating patients into three categories: myopes, hyperopes, and mixed astigmatics. Of the preoperative myopes in the Oculyzer group, 76% remained the same, 5% lost 1 line, 14% gained 1 line, and 5% gained 2 lines of visual acuity at 6 months. In the Topolyzer group, 69% remained the same, 25% gained 1 line, and 6% gained 2 lines of BSCVA. Using the Oculzyer, 95% of myopes, 80% of hyperopes, and 60% of patients with mixed astigmatism were within 10.50 diopters (D) of target refraction. Using the Topolyzer, 88% of myopes, 78% of hyperopes, and 50% of patients with mixed astigmatism were within +/- 0.50 D of target. The outcomes of the preoperative hyperopes and patients with mixed astigmatism are similarly reported. The difference in outcomes between the Oculyzer and Topolyzer cohorts in the myopes and patients with mixed astigmatism was not statistically significant. In the hyperopes, patients treated with the Oculyzer had superior UCVA to those treated with the Topolyzer platform. This case series demonstrates that the Oculyzer and Topolyzer are both effective tools in topography-guided corneal excimer laser surgery. In myopes and patients with mixed astigmatism, both systems were comparable in efficacy and safety. In the hyperopes, the resultant UCVA in the Oculyzer cohort was slightly superior.

Topography-guided LASIK With the WaveLight Laser After Penetrating Keratoplasty

To report a case of topography-guided LASIK in a patient after previous penetrating keratoplasty. A 20-year-old man who had previous penetrating keratoplasty in his right eye for keratoconus and was intolerant to spectacles and contact lenses underwent topography-guided LASIK. Three months postoperatively, the patient's uncorrected visual acuity in the right eye was 20/25(+2). Best spectacle-corrected visual acuity was 20/20, with a manifest refraction of +0.25 -0.75 x 40 degree. Topography-guided LASIK is a useful therapeutic modality to address corneal irregularity after penetrating keratoplasty.

Topography-guided Treatment of Irregular Astigmatism With the WaveLight Excimer Laser

To evaluate the feasibility, safety, and predictability of correcting high irregular astigmatism in symptomatic eyes with the use of topography-guided photoablation. In a prospective, non-comparative case series, 16 consecutive symptomatic eyes of 11 patients with small hyperopic and myopic excimer laser optical zones, decentered and irregular ablation after corneal graft, and corneal scars were operated. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest and cycloplegic refraction, and corneal topography, with asphericity and regularity, were analyzed. LASIK (n = 10) and photorefractive keratectomy (n = 6) were performed using the ALLEGRETTO WAVE excimer laser and T-CAT software (Topography-guided Customized Ablation Treatment; WaveLight Laser Technologie AG, Erlangen, Germany). In the LASIK group, UCVA improved from 0.81 +/- 0.68 IogMAR (20/130) (range: 0.2 to 2.0) to 0.29 +/- 0.21 logMAR (20/39) (range: 0.1 to 0.7) at 6 months. In the PRK group, mean UCVA improved from 0.89 +/- 0.87 IogMAR (20/157) (range: 0.1 to 2.0) to 0.42 +/- 0.35 logMAR (20/53) (range: 0.1 to 1.0) at 6 months. Best spectacle-corrected visual acuity did not change significantly in either group. One PRK patient lost one line of BSCVA. Refractive cylinder for the LASIK group improved from -2.53 +/- 1.71 diopters (D) (range: -0.75 to -5.75 D) to -1.28 +/- 0.99 D (range: 0 to -2.50 D) at 6 months. Refractive cylinder in the PRK group improved from -2.21 +/- 2.11 D (range: -0.25 to -5.50 D) to -1.10 +/- 0.42 D (range: -0.50 to -1.50 D). Index of surface irregularity showed a decrease from 60 +/- 12 (range: 46 to 89) to 50 +/- 9 (range: 32 to 63) at 6 months in the LASIK group whereas no significant change was noted in the PRK group. Subjective symptoms, such as glare, halos, ghost images, starbursts, and monocular diplopia, were not present postoperatively. Topography-guided LASIK and PRK resulted in a significant reduction of refractive cylinder and increase of UCVA, without a significant loss of BSCVA.