Comparison of a single-dose vectored thermal pulsation procedure with 5-day course of daily oral azithromycin for meibomian gland dysfunction.

PURPOSE: This study aims at comparing the efficacy of a single-dose vectored thermal pulsation (VTP) procedure versus 5 days once daily oral azithromycin in patients with meibomian gland disease (MGD) by measuring the symptomatology and ocular surface parameters. MATERIALS AND METHODS: The study was conducted as a prospective, nonrandomized, comparative study over a period of 17 months at a tertiary care center. In this study, 60 patients with MGD were enrolled after they gave their informed consent according to the inclusion-exclusion criteria and were divided into two groups, 30 each in the azithromycin group and the VTP, i.e., the LipiFlow group. One group was treated with oral azithromycin for 5 days and the other group was given LipiFlow treatment. Postprocedure, follow-up was done for 2 weeks, 3 months, and 6 months. RESULTS: A statistically significant difference was noted in the score Standard Patient Evaluation of Eye Dryness questionnaire after 3 months of treatment in both the azithromycin and LipiFlow group (P < 0.0001), and the LipiFlow group showed sustained improvement at 6-month follow-up as score improved to 8.83 ± 2.32, whereas it deteriorated in azithromycin group to 13.77 ± 1.65. Pretreatment Ocular Surface Disease Index score (P = 0.126) and posttreatment (P < 0.0001) showed significant differences in both groups. The LipiFlow group showed an improved score of 25.65 ± 6.11 after 6 months of treatment, whereas it deteriorated to 34.79 ± 4.98 in the azithromycin group. Pretreatment, tear film break-up time (P = 0.28) and 6 months posttreatment score (P < 0.0001) showed significant differences in both groups, but in the LipiFlow group, it improved to 15.30 ± 1.76 after 6 months, whereas in the azithromycin group, it was 10.07 ± 1.60. The pretreatment MG score was 4.10 ± 0.99 and 4.23 ± 1.07 (P = 0.62) in the azithromycin and LipiFlow group, respectively. After 2 weeks, 3 months, and 6 months, the MG score was 24.20 ± 3.38, 21.67 ± 3.46, and 15.83 ± 2.41, respectively, in azithromycin group. In the LipiFlow group, the score was 13 ± 1.88, 14.27 ± 2.07, and 14.37 ± 1.85 at 2 weeks, 3 months, and 6 months, respectively, suggestive of improvement in all visits. CONCLUSION: Both oral azithromycin and LipiFlow treatment are effective in patients with MGD. The effect of LipiFlow treatment lasted longer as compared to azithromycin. The efficacy of azithromycin in resolving the symptoms of MGD was greater compared to LipiFlow in the initial 2 weeks of treatment. However, the effect deteriorated in the subsequent follow-up at 3 months and 6 months.

Comparative analysis of outcomes following topography-guided laser in situ keratomileusis using manifest refraction versus a new topographic analysis algorithm.

Purpose: To compare the visual outcomes following topography-guided laser in situ keratomileusis (LASIK) treatment using manifest refraction versus a new topography analysis software. Methods: A prospective, randomized, observer-masked contralateral study was conducted in the refractive services of a tertiary eye care hospital in South India. Analysis of visual outcomes, corneal higher-order aberrations, and contrast sensitivity were performed at 3 months postoperative visit following uneventful topography-guided LASIK using the Wavelight EX500. One eye was treated with the Contoura platform using manifest refraction (Contoura), while the contralateral eye was treated using an ablation profile planned by the Phorcides Analytic Engine (Phorcides). Results: Sixty eyes of 30 patients were included in the study. At 3 months postoperative visit, the uncorrected distance visual acuity (UDVA) in the Contoura and Phorcides groups was logarithm of the minimal angle of resolution (logMAR) 0.04 ± 0.07 and logMAR 0.06 ± 0.1, respectively (P = 0.483). Postoperative manifest refractive spherical error (MRSE) was 0.12 ± 0.22 and - 0.06 ± 0.20 D in the Contoura and Phorcides groups, respectively (P = 0.338). Although higher number of eyes demonstrated a gain in one or more lines of corrected distance visual acuity (CDVA) in the Contoura group (16.6% vs. 6.6%), the difference was not statistically significant (P = 0.361). Vector analysis (Alpins criteria) for postoperative cylinder, contrast sensitivity measurement, and corneal higher-order aberration profile showed no significant difference between the two groups at 3 months postoperative visit (P = 0.213, 0.514, and 0.332, respectively). Conclusion: Quantitative and qualitative visual outcomes with the Phorcides Analytic Software were similar to the Contoura treatment using manifest refraction.

Comparative analysis of visual outcomes following small-incision lenticule extraction with or without cyclotorsion compensation in eyes with high astigmatism: Contralateral eye study.

Purpose: To compare the visual outcomes in patients undergoing small-incision lenticule extraction (SMILE) for correction of myopic astigmatism (≥-1.50 D) with or without manual cyclotorsion compensation. Methods: A prospective, double-blinded, randomized, contralateral study was conducted in the refractive services of a tertiary eye care center. Eligible patients with bilateral high myopic astigmatism (≥1.5 D) and intraoperative cyclotorsion (≥5°) undergoing SMILE between June 2018 and May 2019 were included. Cyclotorsion compensation was performed using triple centration method before femtosecond laser delivery. Uncorrected and corrected distance visual acuity (UDVA and CDVA, respectively) measurement, manifest refraction, slit-lamp biomicroscopy, and corneal tomography were performed preoperatively and at 1 and 3 months' postoperative visit. Astigmatic outcomes were analyzed using Alpins criteria. Results: A total of 30 patients (60 eyes) were included in this study. The patients underwent bilateral SMILE surgery, with manual cyclotorsion compensation in one eye (CC group, n = 30 eyes) and no cyclotorsion compensation in the other eye (NCC group, n = 30 eyes). Preoperative astigmatism and intraoperative cyclotorsion were -2.0 D and 7.03° ± 1.06° (CC) and -1.75 D and 7.24° ± 0.98° (NCC) (P = 0.472 and 0.240, respectively). No significant differences were noted in mean refractive spherical equivalent (MRSE), UDVA, CDVA, and refractive error between the two groups at 3 months' postoperative visit. Astigmatic outcomes measured using Alpins criteria demonstrated no significant difference between the two cohorts. Conclusion: The cyclotorsion compensation technique provided no additional advantage in terms of astigmatic outcomes or postoperative visual quality, in eyes with high preoperative astigmatism and intraoperative cyclotorsion.

Visual outcomes of early enhancement following small incision lenticule extraction versus laser in situ keratomileusis.

Purpose: To compare visual outcomes of early enhancement following small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK). Methods: Retrospective analysis of eyes (patients operated in the setting of a tertiary eye care hospital between 2014 and 2020) requiring early enhancement (within one year of primary surgery) was conducted. Stability of refractive error, corneal tomography, and anterior segment Optical Coherence Tomography (AS-OCT) for epithelial thickness was performed. The correction post regression was done using photorefractive keratectomy and flap lift in eyes, wherein the primary procedure was SMILE and LASIK, respectively. Pre- and post enhancement corrected and uncorrected distance visual acuity (CDVA and UDVA), mean refractive spherical equivalent (MRSE), and cylinder were analyzed. IBM SPSS statistical software. Results: In total, 6350 and 8176 eyes post SMILE and LASIK, respectively, were analyzed. Of these, 32 eyes of 26 patients (0.5%) post SMILE and 36 eyes of 32 patients (0.44%) post-LASIK required enhancement. Post enhancement (flap lift in LASIK, and PRK in SMILE group) UDVA was logMAR 0.02 ± 0.05 and 0.09 ± 0.16 (P = 0.009), respectively. There was no significant difference between the refractive sphere (P = 0.33) and MRSE (P = 0.09). In total, 62.5% of the eyes in the SMILE group and 80.5% in the LASIK group had a UDVA of 20/20 or better (P = 0.04). Conclusion: PRK post SMILE demonstrated comparable results to flap lift post LASIK and is a safe and effective approach for early enhancement post SMILE.

Outcome of a low-cost glaucoma drainage device with posterior chamber/pars plana insertion of the tube.

INTRODUCTION: The Aurolab aqueous drainage implant (AADI) is a low-cost glaucoma drainage device that is modelled on the Baerveldt glaucoma implant. Studies on AADI have reported absolute success rates of 41.8-93.1% at 1 year. Most studies report on tube placement in the anterior chamber. We report on results of tube insertion in the sulcus/pars plana. MATERIAL AND METHODS: A retrospective chart review of all patients who had undergone AADI implantation (with insertion of tube in the sulcus/posterior segment) between June 2015 and November 2018 was done. Patients were asked to stop anti-glaucoma medications on the 40th post-operative day. RESULTS: The mean age was 57.4 ± 13.8 years (n = 30). The mean IOP prior to surgery was 34.4 ± 6.1 mmHg which reduced to 15.4 ± 8.6 mmHg on the 45th post-operative day (p < 0.001). The absolute success at last review was 10% and the qualified success was 80%. The complication rate was 26.7%. Three patients had hypotony related complications noted at/after the 45th day review (none before 40th day). The incidence of ocular motility disturbances was 26.7% though none of the patients reported diplopia. One patient had sideways rotation of the scleral patch graft resulting in tube exposure. This complication was not seen after we shifted to using 9-0 nylon sutures to anchor the graft. Six patients had loss of best corrected visual acuity and one patient developed endophthalmitis. The endophthalmitis was preceded by conjunctival retraction and sloughing off of the scleral patch graft. DISCUSSION: AADI implantation results in a substantial drop in IOP. However, many patients continue to require anti-glaucoma medications. Allowing overlap of scleral/corneal patch graft onto the scleral flap may be effective in preventing peritubular leak. It may be advisable to use 9-0 nylon sutures to secure the scleral patch graft anti-glaucoma medications can be temporarily suspended after the 40th post-operative day to minimize hypotony related complications. Melting of the scleral patch graft may be an early sign of endophthalmitis. It would be prudent to specifically look for ocular motility problems in patients undergoing AADI implantation.

Comparative Analysis of Safety and Efficacy of Topography-Guided Customized Cross-linking and Standard Cross-linking in the Treatment of Progressive Keratoconus.

PURPOSE: To compare the safety and efficacy of topography-guided customized corneal cross-linking (PiXL) with standard cross-linking (CXL) for the treatment of progressive keratoconus. METHODS: In a prospective interventional analysis, the eyes of patients with progressive keratoconus underwent standard cross-linking (homogenous 9-mm ultraviolet-A irradiation of 9 mW/cm2 delivering a total fluence of 5.4J/cm2) versus topography-guided customized cross-linking (30 mW/cm2 pulsed irradiance with a total fluence ranging from 5.4 to 15 J/cm2, in concentric circles centered on the posterior float maximum). The following parameters were analyzed at the preoperative, 1-month, 6-month, and 1-year postoperative visits: corrected spectacle distance visual acuity, manifest refraction including sphere, cylinder and mean refractive spherical equivalent, corneal tomography, higher order aberration profile, and endothelial cell count. Anterior segment optical coherence tomography evaluation was performed at the 1-month postoperative visit to assess the depth of the demarcation line. RESULTS: Sixty-four eyes of 45 patients (32 eyes in each group) were included. There was a significant reduction in maximum keratometry and IS asymmetry in the PiXL group at both the 6-month and 1-year postoperative visits (P = 0.001 and 0.06). Corrected spectacle distance visual acuity improved significantly in the PiXL (0.05 ± 0.08 logarithm of the minimum angle of resolution, P = 0.02) versus the standard CXL (0.01 ± 0.025 logarithm of the minimum angle of resolution, P = 0.26) group. A greater depth of a stromal demarcation line was observed in the customized CXL group (P = 0.02). No significant complications were noted in either cohort. CONCLUSIONS: PiXL demonstrated similar safety with significantly greater keratometry flattening and corneal regularization vis-à-vis standard CXL. This resulted in significant improvement of spectacle corrected visual acuity for eyes with mild-to-moderate keratoconus.

Topography-guided treatment in regular and irregular corneas.

Over the last decade, refractive surgery has been revolutionized by advancements in ablation profiles, available for the treatment of both regular and irregular corneas. Advances in corneal imaging have helped highlight the presence of higher-order aberrations, the correction of which could result in a better quality of vision. Topographic measurements being static are more repeatable and pupil independent and therefore provide the ideal platform for correction of both lower and higher-order aberrations and could result in improved visual quality even in patients with seemingly regular corneas. The combination of topography-guided treatment with collagen cross-linking has further increased the scope of treating irregular corneas like keratoconus, post-laser in-situ keratomileusis ectasia, and pellucid marginal degeneration. This review delves into the current literature and guidelines available for the topographic treatment of regular and irregular corneas.

Decade - long journey with small incision lenticule extraction: The learnings.

Over the past decade, small incision lenticule extraction (SMILE) has revolutionized the field of keratorefractive surgery. With the promise of superior corneal biomechanics and reduced postoperative dry eye, SMILE afforded a distinct advantage over flap-based procedures. Our evolving understanding of the surgical technique and management of its unique complications has further enhanced the outcomes. This review will highlight specific pearls on various preoperative and intraoperative principles allowing optimization of outcomes with SMILE.

Randomized trial comparing visual outcomes of toric intraocular lens implantation using manual and digital marker.

PURPOSE: The aim of this study was to compare the visual outcome of participants undergoing toric intraocular lens (IOL) implantation after cataract extraction using manual marking versus digital marking for intraoperative guidance. METHODS: Randomized controlled trial of participants with cataract and corneal astigmatism of 1.00 D-4.50 D. The eyes were grouped into manual marking (Group 1) and digital marking (Group 2). Preoperative Uncorrected distance visual acuity (UDVA), Corrected distance visual acuity (CDVA), and corneal astigmatism were determined. IOL power and axis of alignment were determined using Barrett toric calculator. Eyes were marked by bubble marker and Mendez ring in group 1 and by VERION (Alcon, Fort Worth, Texas) digital overlay in Group 2. Postoperatively, UDVA, CDVA, residual refractive cylinder and IOL misalignment were determined (iTrace system, Tracey technologies) at 1 week, 6 weeks, and 3 months. RESULTS: A total of 61 eyes of 50 participants, 31 in Group 1 and 30 in Group 2, were studied. The mean postoperative cylindrical error was 0.50 ± 0.39 D in Group 1 and 0.29 ± 0.34 D in Group 2 (P = 0.03). 67.74% (n = 21) and 93.55% (n = 29) eyes achieved a residual astigmatism of ≤0.50 D and ≤1.00 D, respectively, in Group 1, whereas 83.33% (n = 25) and 100% (n = 30) eyes achieved a residual astigmatism of ≤0.50 D and ≤1.00 D, respectively, in Group 2 at 3 months postoperatively. Toric IOL misalignment was 4.71 ± 3.12° in Group 1 and 4.03 ± 2.99° in Group 2 (P = 0.39). CONCLUSION: Accurate manual marking and digital marking are equally effective guides for toric IOL alignment, intraoperatively.

Ectasia after keratorefractive surgery: Analysis of risk factors and treatment outcomes in the Indian population.

Purpose: To analyze the risk factors in eyes developing ectasia following keratorefractive procedures. In addition, the study assessed visual outcomes following various treatment modalities for ectasia. Methods: In this retrospective study, data of patients who underwent keratorefractive procedures, presenting to the refractive services of a tertiary eye care hospital in South India between January 2016 and May 2019 was analyzed. Of these, the eyes that developed ectasia were noted and the possible risk factors were determined. Visual outcomes following treatment with corneal collagen crosslinking (CXL) with or without intracorneal ring segment implantation (ICRS) or topography-guided corneal ablation (T-PRK) were analyzed. Results: Forty eyes of 26 patients developed ectasia following keratorefractive procedures, with a mean interval of 73.1± 45.4 months between primary procedure and ectasia development. Of these, 14 patients had bilateral presentation. Identifiable risk factors included ablation depth > 75 µm (59.25%), percentage of tissue altered (PTA) > 40% (48.14%), residual stromal bed < 300 µm (22.22%), mean refractive spherical equivalent > 8 D (25.92%), inferior-superior (I-S) asymmetry > 1.4D (7.40%), central corneal thickness (CCT) < 500 µm (7.40%), Belin Ambrosio Display (BAD) > 2.5 (7.40%), posterior float elevation maximum ≥18 µm (3.70%), and pellucid marginal degeneration (PMD; 3.70%). Conclusion: Our study shows that only 70% of the eyes demonstrated an identifiable risk factor for the development of ectasia. Ablation depth of > 75 µm and the PTA > 40% were the most common risk factors. Treatment following CXL with ICRS or T-PRK demonstrated significantly better visual outcomes in comparison with CXL alone.

Impact of anterior capsular polishing on capsule opacification rate in eyes undergoing femtosecond laser-assisted cataract surgery.

Purpose: To evaluate the impact of anterior capsular polishing on capsule opacification and contraction in eyes undergoing femtosecond laser-assisted cataract surgery (FLACS). Methods: This prospective interventional comparative analysis included patients undergoing FLACS between August 2016 and May 2017. The eyes were subdivided into three groups based on the extent of intraoperative anterior capsular polishing performed: complete 360-degree polishing; inferior 180-degree polishing; and no polishing. Visual acuity, posterior capsular opacification (PCO) score, anterior capsular opacification (ACO) grade, and capsulorhexis diameter were evaluated at 1-week, 6-months, and 1-year postoperative visits. Results: The study included 99 eyes of 90 patients. No significant differences were observed between the three groups in ACO grade and capsulorhexis contraction at all follow-up visits. There was a statistically significant difference in PCO grade among the groups at 6-month and 1-year follow-up but it was found to be clinically insignificant. One eye in the no polishing group underwent neodymium:yttrium-aluminum-garnet (Nd:YAG) capsulotomy at the 1-year follow-up visit. Conclusion: A lower incidence of PCO was demonstrated in the 360-degree polishing group, although it was visually insignificant. No significant difference in postoperative capsular contraction was demonstrated between the cohorts up to one-year follow-up.

Stop sign for correct tissue plane identification in small incision lenticule extraction.

We describe the "stop sign" which allows correct anterior and posterior lenticular plane delineation in Small Incision Lenticule Extraction (SMILE). This sign describes the resistance noted at the junction between the dissected and undissected halves of both the planes, interfering with subsequent lateral movement of the instrument. The resistance is demonstrated at both the anterior and posterior lenticular plane. This allows ideal dissection of the lenticule from the overlying cap and underlying stroma, thereby reducing the complications arising from incorrect tissue dissection.

Triamcinolone acetonide for remnant lenticule identification in small incision lenticule extraction.

Lenticule fragments retained postoperatively are a unique complication of small incision lenticule extraction. Large or central remnants with pursuant complications, including irregular astigmatism, induced corneal aberrations, and reduction in visual acuity, warrant surgical removal. Currently described modalities to delineate lenticule remnants include the use of anterior segment optical coherence tomography or CIRCLE software. However, the incurred cost and restricted availability of the described techniques limit their widespread use. The intraoperative administration of diluted triamcinolone acetonide into the intrastromal pocket to delineate lenticule edges, aiding subsequent removal is shown here.

Photorefractive intrastromal corneal crosslinking for treatment of low myopia: clinical outcomes using the transepithelial approach with supplemental oxygen.

PURPOSE: To evaluate the safety and efficacy of photorefractive intrastromal corneal crosslinking (PiXL) for the treatment of low myopia using the epithelium-on approach with supplemental oxygen. SETTING: The Eye Foundation, Coimbatore, India. DESIGN: Prospective interventional case series. METHODS: Myopic nonectatic eyes underwent PiXL using the Mosaic system. Ultraviolet-A (UV-A) irradiation of 365 nm wavelength was delivered in an accelerated (30 mW/cm) pulsed approach to provide a total fluence of 15 J/cm. Supplemental oxygen (concentration greater than 95%) was provided to increase the efficacy of the epithelium-on approach during the UV-A irradiation. Efficacy was determined by improvement in mean refractive spherical equivalent (MRSE), uncorrected distance visual acuity (UDVA), and keratometric flattening. Safety was determined by loss of lines of corrected distance visual acuity, endothelial cell loss, and adverse events. RESULTS: Fifty eyes of 26 patients with a mean age of 22.73 ± 3.74 years were included. A significant improvement in UDVA from baseline (logarithm of the minimum angle of resolution [logMAR] 0.63 ± 0.25) was noted at the 3-month (logMAR 0.08 ± 0.15) and 6-month (logMAR 0.13 ± 0.18) follow-up visits (P < .001). Significant keratometric flattening from baseline was noted at all follow-up visits (P < .001). No significant endothelial cell loss or adverse effects were noted. A significant correlation was noted between the change in MRSE and preoperative corneal biomechanics (deformation amplitude ratio, P = .029). CONCLUSIONS: Transepithelial PiXL with supplemental oxygen might be a safe and effective approach for reduction of myopia. The change in MRSE and keratometric flattening was greater in comparison with earlier protocols, including the epithelium-off approach.

Comparative analysis of clinical outcomes between two types of posterior chamber phakic intraocular lenses for correction of myopia and myopic astigmatism.

Purpose: To compare clinical outcomes following implantation of two types of posterior chamber phakic intraocular lenses: Visian™ Implantable Collamer Lens with Centraflow (ICL, V4C Staar Surgical, Nidau, Switzerland) and Implantable Phakic Contact Lens (IPCL, V1, Caregroup Sight Solution, India) for the correction of myopia and myopic astigmatism. Methods: This retrospective case series included eyes which underwent phakic intraocular lens implantation with a minimum follow-up period of 1 year. Visual outcomes including safety, efficacy, refractive predictability, and stability were compared at 1 week and at 1, 6, and 12 months' postoperative visit. Complications and adverse events were analyzed. Results: The study included 119 and 203 eyes in the IPCL and ICL groups, respectively. At 1-year postoperative visit, median corrected distance visual acuity was 0.10 (interquartile range [IQR] 0,0.10) and 0 (IQR 0,0) in the IPCL and ICL cohorts, respectively (P = 0.066). An uncorrected visual acuity of 20/32 or better was achieved in 86.5% and 88.67% of the eyes, respectively (P = 0.574). Ninety and 94% of the eyes achieved a postoperative manifest spherical equivalent within ± 0.5D (P = 0.169, χ2 test). Three eyes (2.52%) in the IPCL group versus one eye (0.49%) in the ICL group developed visually significant cataract requiring surgical intervention (P = 0.113). No vision-threatening complications were noted in either cohort. The mean follow-up period was 94.69 ± 32.45 and 102.67 ± 61.82 weeks, respectively. Conclusion: Both groups demonstrated similar efficacy and safety profile. The IPCL is an effective and economically viable option for the correction of myopia.

Comparative analysis of visual outcomes and ocular aberrations following wavefront optimized and topography-guided customized femtosecond laser in situ keratomileusis for myopia and myopic astigmatism: A contralateral eye study.

PURPOSE: To compare the visual outcomes and higher order aberrations (HOAs) following wavefront optimized (WFO) laser in situ keratomileusis (LASIK) versus topography-guided customized ablation (TCAT) LASIK for myopia and myopic astigmatism. METHODS: Patients who underwent femtosecond-assisted LASIK for myopic correction between August 2016 and October 2017 were included in this interventional prospective case series. The following parameters were evaluated preoperatively and at 3 months' postoperative visit: uncorrected distance vision acuity (UDVA) and corrected distance vision acuity (CDVA), manifest refraction, and HOAs. RESULTS: Two hundred eyes of 100 patients were included in the study. At 3 months' postoperative visit, 92% and 90% eyes in the TCAT and WFO groups, respectively, demonstrated a UDVA of 20/20 or better (P = 0.90). A residual manifest spherical equivalent within 0.5 D was achieved in 100% and 95% of the eyes in the TCAT and WFO groups, respectively (P = 0.10). No significant difference was observed in the HOAs induced in both the groups, with slightly lower induction of trefoil and horizontal coma in the TCAT group. CONCLUSION: Both groups demonstrated similar refractive efficacy and predictability, with greater gain of CDVA following TCAT ablation. HOAs induced were not significantly different between the two groups. Further studies are needed to validate the superiority of one procedure over the other.

Comparative analysis of safety and efficacy of photorefractive keratectomy versus photorefractive keratectomy combined with crosslinking.

PURPOSE: To assess the safety, efficacy, and refractive predictability of half-fluence accelerated corneal collagen crosslinking (CXL) applied concurrently with photorefractive keratectomy (PRK), and compare the results to standard PRK. SETTING: Refractive Services, The Eye Foundation, Coimbatore, India. DESIGN: Interventional comparative case series. METHODS: Patients seeking refractive correction for myopia or myopic astigmatism were included in the study. Photorefractive keratectomy with concurrent half-fluence crosslinking (PRK Xtra) was performed in eyes with borderline suspicious tomography (not amounting to forme fruste keratoconus) or low pachymetry between 450 and 474 µm with an otherwise unremarkable corneal tomography. Eyes with normal corneal tomography and thickness between 475 and 500 µm underwent standard PRK. The minimum follow-up period was 1 year. RESULTS: In total, 109 eyes underwent PRK Xtra (Group A) and 118 eyes underwent PRK alone (Group B). The preoperative MRSE was -3.64 D and -3.38 D in Groups A and B, respectively (P=0.28). Group A had a significantly higher number of eyes with thinner corneas (P<0.01) and corneal tomographic abnormalities (P=0.02). At 1 year follow-up, 96.3% of eyes in group A as against 99.1% of eyes in group B achieved a best corrected distance visual acuity (CDVA) of 20/20 or better. No iatrogenic ectasia or hyperopic shift secondary to progressive flattening was noted in the PRK Xtra group. No significant difference in incidence of haze was noted. CONCLUSION: PRK Xtra showed comparable safety, efficacy, and stability to PRK in eyes with thinner pachymetry and tomographic abnormalities. Combining crosslinking with PRK in suspicious tomographies augurs for safe and predictable outcomes.