Comparison of Ectasia versus Pseudoectasia using the Ectasia Risk Factor Score System

Objectives@#To evaluate and compare ectasia and pseudoectasia in post-myopic LASIK patients presenting with corneal topographic changes indicative of ectasia using the Ectasia Risk Factor Score System (ERFSS).@*Methods@#Single-center retrospective comparative case series of a consecutive chart review of cases in 18 years who underwent bilateral myopic-LASIK and showed topographic changes indicative of ectasia.@*Results@#Four patients were included. Group 1: pseudoectasia eyes, consisting of two patients with bilateral pseudoectasia, and Group 2: ectasia eyes, consisting of two patients with unilateral ectasia. The clinical course of the cases was discussed and compared based on the ERFSS parameters: topography pattern, residual stromal bed thickness, age, preop thinnest cornea, and pre-operative spherical equivalent (SE) manifest refraction (MR). Group 1 scored zero to low risk for developing ectasia while Group 2-eyes with ectasia scored moderate risk. The predictive value of the ERFSS was 1 in this study.@*Conclusion@#The ERFSS is a good measure in deciding the suited treatment plan for patient undergoing refractive procedure. Knowing the clinical course of ectasia and pseudoectasia is helpful in the therapeutic approach since pseudoectasia is reversible when identified and managed early as seen in this study.

Comparison of visual performance of monofocal intraocular lenses with different asphericities

Objective@#To compare the visual performance and patient-reported outcomes of three types of monofocal intraocular lenses (IOL) with different asphericities.@*Methods@#This cross-sectional, comparative study comprised of 62 pseudophakic eyes divided into three groups corresponding to the IOL that they were previously implanted with (Tecnis ZCB00 negative aspheric IOL, EnVista MX60 neutral aspheric IOL and Akreos Adapt spheric IOL). Mean refractive spherical equivalent (MRSE), best-corrected far visual acuity (BCVA), spherical aberration (SA), contrast sensitivity (SC), halo and starburst, and responses to a qualitative questionnaire (NEI-RQL) were measured.@*Results@#There was no significant difference in MRSE (P=0.74) and BCVA (P=0.52) among the three groups. There was a statistically significant difference (P=0.00) in mean internal (lens) SA, measured through a 5mm pupil, among Tecnis (-0.150 μm), EnVista (+0.022 μm) and Akreos Adapt (+0.094 μm). Compared to the Akreos Adapt, the Tecnis and EnVista groups had significantly better CS at 6 CPD and 12 CPD under mesopic testing without glare (P= 0.01) and at 6 CPD mesopic testing with glare (P=0.04). Halo scores were insignificant among the three groups. However, starburst scores were significantly worse in the Akreos Adapt IOL than the Tecnis and EnVista (P=0.01). There was no difference in questionnaire responses among the three groups.@*Conclusion@#The negative aspheric and neutral aspheric lenses showed significantly lower SA resulting in better CS in mesopic conditions and better starburst scores. MRSE, BCVA and subjective satisfaction were statistically similar regardless of the type of monofocal intraocular lens

A comparative evaluation of visual, refractive, and patient-reported outcomes of three diffractive trifocal intraocular lenses

@#OBJECTIVE: To compare the visual, refractive, and patient-reported outcomes of eyes implanted with one of 3 trifocal intraocular lenses (IOLs). METHODS: This is a cross-sectional, comparative, non-interventional study wherein subjects implanted with FineVision Micro F, AT LISA tri 839MP or AcrySof IQ PanOptix trifocal IOL after phacoemulsification were recruited. Manifest refraction, uncorrected and corrected visual acuity (VA) at distance, intermediate and near vision, contrast sensitivity, modulated transfer function (MTF) values and questionnaire answers were compared among the 3 groups using analysis of variance (ANOVA). RESULTS: Fifty-seven (57) eyes were included in the study: 21 eyes with FineVision (group A), 21 eyes with LISA tri (group B), and 15 eyes with PanOptix IOL (group C). The post-operative mean manifest spherical equivalent was -0.01D, -0.07D, and 0.05D, respectively (p=0.083). Uncorrected distance VA and best-corrected distance VA were similar among the groups. Groups A and C had better uncorrected and corrected intermediate VA at 80 cm and at 60 cm compared to group B. Group A had significantly better uncorrected near visual acuity than groups B and C (p=0.032). Mesopic contrast sensitivity testing showed group C had higher contrast sensitivities without glare in at the spatial frequency of 6 CPD (p=0.038) and with glare at 3 CPD (p=0.039) and at 12 CPD (p=0.009). MTF average height analysis showed that the group A had significantly superior resolution in far targets compared to groups B and C (p=0.001). At near targets, groups A and C had better resolutions compared to group B (p=0.017). There was no significant difference in patient satisfaction for far, intermediate and near VA among the groups. CONCLUSION: Eyes implanted with any of the 3 trifocal IOL designs achieved excellent uncorrected and bestcorrected distance, intermediate and near vision. FineVision and PanOptix provided significantly better intermediate vision than LISA tri at both 80 cm and 60 cm testing distance. FineVision had better near visual outcomes than PanOptix and LISA tri. Patient satisfaction was high in all 3 trifocal IOLS

Survey of glaucoma practice patterns among members of The Philippine Glaucoma Society

@#OBJECTIVE: To identify the glaucoma clinical practice patterns among the members of the Philippine Glaucoma Society (PGS) from 2015 to 2016 using an online survey. METHODS: An online link was sent to each consenting PGS member which directed them to two poll sites. These sites asked questions about demographics and their preferred clinical practice patterns. Frequency and percent distributions were used to analyze the data. RESULTS: There was a high response rate from PGS members at 97% (42 out of 43 members). More than half of respondents (51%, n=22) defined glaucoma as glaucomatous optic neuropathy with an evident visual field loss. IOP was routinely measured by 90% (n=38) of the respondents with majority preferring to use the Goldmann applanation tonometer (GAT) (98%, n=41). Gonioscopy was done on all new patients by all PGS members but only 62% did regular gonioscopy on follow-up consultations. Most of the respondents relied on the 90D lens (88%) to assess the optic nerve. Visual field examination (VFE) was routinely requested by all respondents. Pachymetry and anterior segment optical coherence tomography (AS-OCT) were used sparingly at only 43% and 12% respectively. Appositional angle closure was addressed by performing laser iridotomy with majority of the respondents preferring a site that is covered by the upper eyelid (57%). Prostaglandin analogues were the top choice as first-line monotherapy for eyes with open-angle glaucoma. Majority of the respondents (55%) opted to do laser trabeculoplasty (LTP) as an adjunct to medical therapy. Mitomycin-C was the preferred intraoperative antimetabolite for trabeculectomy by 98% (n=41). Ahmed (71%, n=30) was the more favored glaucoma drainage device (GDD) by our respondents over Baerveldt (19%, n=8). CONCLUSION: This survey showed majority of the glaucoma practices of PGS members appear to adhere to the current clinical practice guidelines.

Comparison of the clinical profile of patients with glaucoma between private and government clinics in the Philippines

@#<p style="text-align: justify;"><strong>OBJECTIVE</strong>: To describe the demographic and clinical characteristics of patients with glaucoma managed at private and government institutions in the Philippines between 2009 and 2014.</p><p style="text-align: justify;"><strong>METHODS</strong>: A research team from two private and two government institutions in the Philippines reviewed the case records of 1246 patients seen who met the following criteria: intraocular pressure of >21 mmHg, optic nerve and nerve fiber layer abnormalities, and visual field defects. For bilateral cases, we selected the eye with worse glaucoma parameters.</p><p style="text-align: justify;"><strong>RESULTS</strong>: There were 600 and 646 patients in the private and government groups (mean age at presentation, 60.51 and 55.88 years), respectively, with the majority being Filipino (91%). Patients with visual acuity (VA) of 20/20 to 20/40 were more frequently observed in private centers (58.7% vs. 41.3%), while a VA worse than counting fingers was more frequently observed in government centers (66.1% vs. 33.9%). Within-group analysis showed that primary angle-closure glaucoma was the most frequent glaucoma subtype in both private (27.3%) and government institutions (37.8%). In between-group analysis showed the following to be more common in private than government centers: primary open-angle glaucoma (61.3% vs. 38.7%), normal-tension glaucoma (63.9% vs. 36.1%), ocular hypertension (92.3% vs. 7.7%), and glaucoma suspects (80.4% vs. 19.6%) while government institutions registered a larger number of primary angle-closure glaucoma (59.8% vs. 40.2%) and secondary glaucoma (70.3% vs. 29.7%) cases. Medical treatment using a single drug and multiple drugs was employed for 245 (23%) and 825 (77%) patients, respectively. Within-group analysis showed that laser iridotomy and trabeculectomy were the most commonly performed laser and surgical procedures in both institution types.</p><p style="text-align: justify;"><strong>CONCLUSION</strong>: There is a contrasting profile of glaucoma between clinical institutions in the Philippines with openangle glaucoma being more predominant in private centers while closed-angle glaucoma and secondary glaucoma being more frequent in government centers. Our findings may provide important preliminary information that can aid future health studies or training programs.</p>

Measurement of accommodative amplitude using wavefront aberrometer

@#<p style="font-size: 12.16px; text-align: justify;"><strong>OBJECTIVE:</strong> To measure and compare the accommodative amplitude of Filipino patients with different accommodative conditions using a wavefront aberrometer.</p> <p style="font-size: 12.16px; text-align: justify;"><strong>METHODS:</strong> A total of 120 eyes of 67 patients seen in a private eye center were included and divided into two groups (phakic and pseudophakic). After undergoing routine ophthalmologic examination that included manifest refraction and visual acuity testing, accomodative amplitude was measured using the iTraceTM wavefront aberrometer. Comparison of the measurements was made between the accommodative amplitude of phakic pre-presbyopes and presbyopes, and between eyes implanted with monofocal and accommodating intraocular lenses (IOLs).</p> <p style="font-size: 12.16px; text-align: justify;"><strong>RESULTS</strong>: The mean age of the pre-presbyopes was 27 years, presbyopes 50 years, monofocal IOL 69 years and accommodating IOL 67 years. The mean accommodative amplitude of the pre-presbyopes was 1.64 ± 1.06D, presbyopes 0.99 ± 0.42D, monofocal IOL 0.36 ± 1.16D, and accommodating IOL 0.94 ± 0.89D. The pre-presbyopes had a higher accommodative amplitude than the presbyopes (p=0.008), while the accommodating IOL subgroup had a higher amplitude than the monofocal IOL subgroup (p=0.02). Increasing age was correlated with decreasing amplitude in the phakic group (r2=0.926). There was no correlation between refractive error and amplitude of accommodation in the phakic and pseudophakic groups (r2=0.02 for both groups).</p> <p style="font-size: 12.16px; text-align: justify;"><strong>CONCLUSION:</strong> The wavefront aberrometer is a reliable tool in objectively measuring accommodative amplitude. Pre-presbyopes and accommodating IOLs were shown to have higher amplitudes of accommodation than presbyopes and monofocal IOLs.</p>

The quality of life in patients with non-surgical and surgical presbyopic corrections

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To compare the quality of life using the National Eye Institute Refractive Error Quality of Life (NEI-RQL) instrument in 40-60 year-old patients with reading glasses and presbyopic LASIK correction and in 60-80 year-old patients with monofocal and multifocal intraocular lenses (IOLs).</p> <p style="text-align: justify;"><strong>METHODS:</strong> Patients aged 40-80 years old with reading glasses (group 1a) or presbyopic LASIK treatment (group 1b) and bilateral pseudophakia with monofocal (group 2a) or multifocal IOLs (group 2b) were recruited. All patients answered the NEI-RQL questionnaire. The responses in the self-administered questionnaires were collated, analyzed, and compared between the subgroups.</p> <p style="text-align: justify;"><strong>RESULTS</strong>: One hundred fifty patients (median age 60 years, range 41-80 years) completed the NEI-RQL questionnaire. Subjects (age 41-59 years) who underwent presbyopic LASIK correction had a higher mean NEI-RQL (p=0.19) and higher subscale score for satisfaction (p=0.42) than those wearing reading glasses. However, the differences were not satistically significant.</p> <p style="text-align: justify;"><strong>CONCLUSION:</strong> Presbyopic LASIK improved uncorrected near visual acuity and provided spectacle independence in presbyopes; however, patient satisfaction was similar to those who with reading glasses. Multifocal IOLs significantly improved uncorrected near visual acuity and spectacle independence in pseudophakic patients with high patient satisfaction.</p>

A five-year review of refractive procedures, outcomes and complications

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To evaluate the visual and refractive outcomes of LASIK, PRK, phakic IOL, and Supracor as treatment for errors of refraction, including presbyopia, performed at a private eye center.<br /><br /><strong>METHODS:</strong> This is a retrospective, single-center, single-surgeon study that reviewed the surgical outcomes of patients who underwent LASIK, PRK, phakic IOL, and Supracor from January 2010 to December 2014. Main outcome measures were postoperative uncorrected and corrected distance, intermediate, and near visual acuity (for Supracor), and mean manifest-refraction spherical equivalent (MRSE) of patients who had at least 1 month follow up. Complications and enhancements were analyzed independently.<br /><br /><strong>RESULTS:</strong> Data were analyzed from 1,366 eyes of 771 patients. LASIK was the most commonly performed procedure (68%), followed by PRK (18.3%), Supracor (10.2%), and phakic IOL (3.7%). The postoperative mean MRSE at 1 month for LASIK, PRK, and phakic IOL were -0.08 ± 0.36, +0.06 ± 0.52 and -0.11 ± 0.44, respectively. The mean postoperative logMAR uncorrected distance visual acuity (UDVA) at 1 month for LASIK, PRK, and phakic IOL were 0.02 ± 0.10, 0.07 ± 0.12, 0.001 ± 0.09, respectively. In the Supracor group, the mean preoperative and postoperative spherical equivalent were +1.12 ± 0.8 and -0.76 ± 0.62, respectively. The mean postoperative logMAR UDVA and uncorrected near visual acuity (UNVA) for Supracor were 0.24 ± 0.19 and 0.02 ± 0.08, respectively. The most common postoperative complication was symptomatic dry eye (13%). Regression and off-target outcomes occurred in 24 (1.8%) and 13 eyes (1%), respectively. Overall enhancement rate was 2%.<br /><br /><strong>CONCLUSION:</strong> LASIK remained to be the most common refractive procedure, with femtosecond laser-created flap becoming the norm. Refractive and visual outcomes showed good efficacy with all the refractive procedures. Complication and enhancement rates were low.</p>

Demographic and clinical profile of patients who underwent refractive surgery screening

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To describe the demographic and clinical profile of patients who underwent refractive surgery screening.<br /><br /><strong>METHODS:</strong> Medical records of patients who sought consult for refractive surgery from January 2010 to December 2014 at a refractive center were reviewed and analyzed. The preoperative clinical conditions, optical characteristics of myopes and hyperopes, refractive screening tests, and causes for disqualification were determined.<br /><br /><strong>RESULTS:</strong> A total of 1215 patients who sought consult for refractive surgery had a mean age of 36.45 ± 11.60 years. Seven hundred ten (58.44%) were females and 860 (70.78%) were Filipinos. Nine hundred eighty eight (81%) were myopes. The mean manifest refractive spherical equivalent (MRSE) for myopic patients was -4.41D±2.98 with mean uncorrected distance vision (UCDVA) of 20/400 (logMAR 1.26) and mean best-corrected distance vision (BCDVA) of 20/20 (logMAR 0.02). For hyperopic patients, the mean MRSE was +1.33D±3.76 with mean UCDVA of 20/40 (logMAR 0.33) and mean BCDVA of 20/20 (logMAR 0.001). Reasons for disqualification from undergoing a refractive procedure included thin cornea (5.27%), irregular corneal topography (2.39%), steep cornea (0.78%), high refractive errors (0.41%), optic nerve (0.41%), and retina (0.25%) pathologies.<br /><br /><strong>CONCLUSION:</strong> Patients who underwent screening for refractive surgery were young, mostly female, with myopic refractive errors. LASIK remained the most popular refractive surgery procedure. </p>

Comparison of the rotational stability of different toric intraocular lens implants

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To compare the rotational stability and cylinder reduction of different toric intraocular lenses (IOLs).<br /><strong>METHOD:</strong> This was a prospective, cross-sectional study of 68 eyes that had at least 0.75 diopters (D) of corneal astigmatism prior to cataract surgery and were at least 3 months post-toric IOL implantation (Envista, AcrySof, FineVision). Patients recruited underwent visual acuity testing, manifest refraction, pupil dilation, and toric IOL axis determination. Actual axis position was obtained and compared to the intended axis calculated from the tonic IOL calculator. Any difference between the two was considered an axis deviation. Main outcome measures were postoperative deviation of the IOL axis from the intended axis, uncorrected distance visual acuity (LIDVA), best corrected distance visual acuity (BCDVA), manifest refraction, and cylinder reduction.<br /><strong>RESULTS:</strong> There was no significant difference in the rotational stability of the three different types of toric IOLs (p=0.95). Mean axis deviation for .AcrySof, Envista, and FineVision were 2.43, 2.66, and 2.75 degrees, respectively. There was a significant decrease in the cylinder from preoperative to postoperative levels for all groups (p=0.00 for Envista, p=0.03 for AcrySof, and p=0.00 for Fine-Vision). There were significant improvements in the mean UCVA and BCDVA after cataract surgery and implantation of toric IOLs for all three groups.<br /><strong>CONCLUSION:</strong> The three IOL platforms (AcrySof, Envista, and FineVision) showed good rotational stability and significant cylinder reduction:Visual and refractive outcomes improved after surgery.<br /><br /></p>

Refractive and visual outcomes of surgical treatments for high myopia

Objective@#To present the refractive and visual outcomes of refractive surgical treatment options in high myopia. @*Methods@#This was a retrospective review of patients diagnosed with high myopia (manifest refractive spherical equivalent [MRSE] ≥-6.00D) who underwent one of the following procedures: laser-in-situ keratomileusis (LASIK), photorefractive keratectomy (PRK), phakic IOL implantation with the Staar Implantable Collamer Lens (ICL), or Alcon Cachet Phakic IOL. Eyes with best corrected distance vision of less than 20/30 due to amblyopia or other eye pathologies were excluded.

Incidence, indications, and outcomes of Yag Capsulotomy in eyes Implanted with an accommodating intraocular lens

Objectives@#To do report the incidence of capsular changes in Crystalens-implanted eyes and analyze the indications and outcomes of yag capsulotomy. @*Methods@#We reviewed the records of 411 eyes of 258 patients implanted with the Crystalens IOL. Capsular change indications for yag capsulotomy were posterior capsular opacification (PCO), lens tilt, and capsular striae. Eyes in each indication were further subdivided into therapeutic yag (TY) and prophylactic yag (PY) groups. Outcomes before and after yag capsulotomy were analyzed. @*Results@#Ninety of 411 crystalens-implanted eyes (22%) had undergone yag capsulotomy. Sixty-one eyes had PCO, 12 had lens tilt, and 17 had striae. Twenty-seven eyes belonged to the therapeutic (TY) and 63 eyes to the prophylactic (PY) yag subgroups. The mean interval between phacoemulsification and yag capsulotomy was 10 months. In the TY PCO subgroup, uncorrected distance visual acuity (UDVA) changed from 20/40 pre-yag to 20/25 post-yag, uncorrected near visual acuity (UNVA) from J3 to J2, manifest refraction spherical equivalent (MRSE) from -0.43D to -0.2D. In the TY tilt subgroup, UDVA changed from 20/50 to 20/30, UNVA was unchanged at J2, and MRSE from -1.21D to -0.89D. In the TY striae group, UDVA changed from 20/50 to 20/30, UNVA from J3 to J2, and MRSE from 0.62D to -0.4D. In the PY PCO subgroup, UDVA was unchanged at 20/25, UNVA unchanged at J2, and MRSE changed from -0.52D to -0.47D. In the PY tilt subgroup, UDVA changed from 20/25 to 20/20, UNVA unchanged at J2, and MRSE changed from -0.87D to -0.45D. In the PY striae subgroup, UDVA was unchanged at 20/30, UNVA changed from J3 to J2, and MRSE changed from -0.62D to -0.7D. @*Conclusion@#Capsular changes occurred after Crystalens implantation that necessitated yag capsulotomy. Once vision has deteriorated, a therapeutic yag treatment can help improve vision. If capsular changes have occurred but vision has not deteriorated, a prophylactic yag capsulotomy can stabilize visual and refractive outcomes.

Comparison of flap thickness, visual outcomes, and higher order aberrations in eyes that underwent LASIK flap creation using a femtosecond laser versus a mechanical microkeratome

Objective@#To compare the predictability of flap thickness, visual and refractive outcomes, and higher order aberrations in eyes that underwent myopic LASIK using either a Technolas femtosecond laser or a Zyoptix XP mechanical microkeratome for flap creation.@*Methods@#The study involved a total of 44 eyes of 22 patients who underwent LASIK. Flap creation was randomized to using the Technolas femtosecond laser in one eye and Zyoptix XP microkeratome in the contralateral eye. Flap thickness was measured intraoperatively using ultrasonic pachymetry and postoperatively using the Visante ASOCT. Refractive outcome, visual acuity (VA), higher order aberrations, and contrast sensitivity were compared between the two groups.@*Results@#Twenty-two patients had LASIK for myopia or myopic astigmatism. Using ultrasonic pachymetry intraoperatively, the mean flap thickness was 134 (±10) um and 124 (±23) um in the femtosecond (FS) and microkeratome (MK) groups respectively. Comparing the deviation of the actual from the intended flap thickness, the FS group had statistically lower standard deviation compared to the MK group (p=0.04). Using the AS-OCT, the mean flap thickness at 3 months postoperatively was 119 (±10.82) um and 123 (±15.77) um in the FS and MK groups respectively. The difference in standard deviation between the two groups did not reach statistical significance (p=0.19). The mean spherical equivalent at 3 months was -0.45D (±0.42) and -0.13D (±0.16) respectively. Eightynine percent (89%) of eyes had uncorrected VA of 20/20 or better in both groups. All eyes attained best corrected VA of 20/20 or better in both groups. Differences in total higher order aberrations (p=0.09) and contrast sensitivity scores (p=0.47) were not statistically different between the two groups. @*Conclusion@#Flap thickness predictability was better using the Technolas femtosecond laser compared to the XP microkeratome blade. Visual and refractive outcomes, higher order aberrations, and contrast sensitivity were comparable between the 2 groups.

Clinical comparison of visual and refractive outcomes of two models of accommodative intraocular lenses

Objective@#To evaluate the visual and refractive outcomes of eyes implanted with the Crystalens HD and the Crystalens AO intraocular lens.@*Methods@#We retrospectively reviewed the records of 159 eyes of 100 patients implanted with the Crystalens HD IOL and 108 eyes of 66 patients implanted with the Crystalens AO IOL. Visual and refractive outcomes preoperatively and postoperatively were assessed and compared between the lenses. @*Results@#At 1 year, uncorrected distance VA was 20/30 in 78% of eyes in the HD and 76% of eyes in the AO groups. Uncorrected intermediate VA was 20/30 in 90% of eyes in both groups. Uncorrected near VA was J3 in 92% in the HD and 90% in the AO groups. Comparing the two groups, the difference in uncorrected distance (p=0.60), intermediate (p=0.77), and near (p=0.64) vision was not statistically significant. Spherical equivalent was -0.42D +/-0.51D in the HD and -0.6 +/-0.48D in the AO groups (p=0.10). @*Conclusion@#Refractive outcomes were similar between the Crystalens HD and AO groups. Mild myopic refractive outcomes were targeted and achieved in both lens groups. These refractive outcomes provided good uncorrected distance, intermediate, and near vision postoperatively.

Visual outcomes and higher-order aberrations of wavefront vs. combined wavefront aspheric

Objective@#We compared the efficacy, safety, refractive and visual outcomes, and aberrometry results of wavefront-guided aspheric treatment (WTA) versus wavefront-guided treatment (WT).@*Methods@#This prospective, contralateral, comparative study included 60 eyes of 30 patients who underwent myopic LASIK. One eye of each patient was randomized to either WTA or WT. Patients were followed up for 3 months postoperatively. Two-tailed paired t-test was used to determine statistical significance.@*Results@#At 3 months, 93% of eyes in the WTA group and 83% in the WT group had high-contrast uncorrected distance visual acuity (UDVA) of 20/20, while 87% in both groups achieved low-contrast UDVA of 20/40 or better. Sixty-four percent in the WTA gained 1 or more lines of low-contrast corrected distance visual acuity (CDVA) compared to 50% in the WT group. The mean sphere was 0.17D in the WTA and 0.14D in the WT (p = 0.63). The mean spherical equivalent was –0.04D for WTA and –0.03D for WT (p = 0.88). All eyes in both groups were within ±1.00D of the target emmetropia. The mean change in total higher-order aberration (HOA) was 0.07 μm in the WTA compared to 0.15 μm in the WT group (p = 0.04). The mean change in spherical aberration was –0.01 μm in the WTA and 0.18 μm in the WT group (p < 0.001). The mean change in Q value was significantly lower in the WTA (0.31) than in the WT group (0.63) (p < 0.001).@*Conclusion@#Wavefront aspheric LASIK (WTA) is a safe and effective treatment for myopic astigmatism. Refractive and visual outcomes were similar for both groups. WTA had less induction of higher-order aberration, lower spherical aberration, and better preservation of corneal asphericity (Q value). This translated to more lines of low-contrast vision gained compared to WT. Keywords: LASIK, Wavefront-guided, Aspheric, Spherical aberration, higher-order aberration, Corneal curvature

A comparative study between the schwind and zyoptix XP microkeratomes

@#Objectives To compare the flap thickness created by two different microkeratomes and its effect on visual outcomes. Methods This prospective study involved 32 eyes of 16 patients who underwent laser in situ keratomileusis (LASIK). Flap creation was randomly assigned to either the Schwind (110 ?m) or Zyoptix XP (120 ?m) microkeratome. Flap thickness was measured using the subtraction technique. Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), low-contrast sensitivity, and aberrometry measurements were compared preoperatively and at 6 months postoperatively. Results The mean flap thickness was 97 ± 13 ?m (range, 81 to 116 ?m) and 146 ± 27 ?m (range, 71 to 181 ?m) using the Schwind and XP respectively. The mean deviation from the labeled predicted thickness was –13 ± 13 ?m and 26 ± 27 ?m respectively, and this difference was statistically significant (p = 0.002). Three eyes had flap displacement, 1 had loose epithelium, and 1 had flap striae in the Schwind group. There were no complications in the XP group. At 6 months, 71% of eyes had UCVA of 20/20 or better in both groups. All eyes attained BCVA of 20/30 or better with spherical equivalent within ±1D of targeted emmetropia in both groups. Low-contrast sensitivity scores were higher in the Schwind group in most frequencies; however, the differences were not statistically significant. The mean change in the total higher-order aberration (HOA), trefoil, coma, quadrafoil was comparable between the groups. The mean change in spherical aberration was smaller (p = 0.03) in the Schwind (0.12 ± 0.35) than in the XP group (0.96 ± 1.3). Conclusion Flap thickness was more predictable with the Schwind than the XP. Schwind flaps were thinner, which may have resulted in more flap complications. Vision and refractive results were similar for both groups. There was no statistically significant difference in HOA; however, spherical aberration was significantly lower in the Schwind.