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.

Limited pars-plana vitrectomy for optimizing surgical outcome in subluxated cataracts undergoing femtosecond laser-assisted cataract surgery.

We propose a technique for combined femto laser-assisted cataract surgery (FLACS) and limited vitrectomy from the pars-plana site for optimization of surgical results in subluxated cataracts. FLACS creates a free-floating, customised capsulotomy, minimizes stress on compromised zonules, and prechops the nucleus, effectively reducing the ultrasonic power as well as the forces required to chop the nucleus. The area of zonular dehiscence creates a direct communication between the irrigation fluid and the anterior vitreous, leading to its hydration. Trans-limbal vitrectomy creates a continuum between the liquefied vitreous and the main wound, leading to further vitreous loss, and exaggeration of the zonular weakness, while pars-plana vitrectomy avoids this by cutting the liquefied vitreous, near its attachment, thereby preventing further hydration and causing lesser stress to the zonules. A combination of these procedures, along with a capsule support device, gives favorable surgical outcomes in moderate to severe subluxations.

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.

Intra corneal ring segment implantation with lenticule assisted stromal augmentation for crosslinking in thin corneas.

PURPOSE: To evaluate the safety and efficacy of intra corneal ring segment (ICRS) implantation combined with crosslinking (CXL) using a Small Incision Lenticule Extraction (SMILE) lenticule for intraoperative stromal augmentation in thin corneas. OBSERVATIONS: The procedure was performed in three eyes of progressive keratoconus or post refractive surgery corneal ectasia, with a preoperative mean thinnest pachymetry of 389.34 ± 5.5 µm. Keratometry flattening (preoperative mean maximum keratometry of 63.17 ± 9.31D to postoperative mean maximum keratometry of 54.77 ± 9.47D) and improvement in spectacle corrected distance visual acuity (mean preoperative LogMAR 0.43 ± 0.19 to mean postoperative LogMAR 0.71 ± 0.26) was noted at three months, with stability at one-year postoperative visit. Demarcation line was demonstrated at a depth of 220.67 ± 8.32 µm. No significant endothelial cell loss was noted. CONCLUSIONS AND IMPORTANCE: Intraoperative stromal thickness augmentation using a lenticule obtained from SMILE allows safe and effective CXL in combination with ICRS in ultrathin corneas. This allows an alternative to lamellar keratoplasty for visual rehabilitation in such eyes.

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.

Femtosecond laser-integrated anterior segment optical coherence tomography to detect preexisting posterior capsular dehiscence and increase safety in posterior polar cataracts.

PURPOSE: To determine the efficacy of the femtosecond laser with integrated anterior segment optical coherence tomography (AS-OCT) for the detection of posterior capsular dehiscence in posterior polar cataracts (PPCs). To evaluate the safety of phacoemulsification in these eyes undergoing femtosecond laser-assisted cataract surgery (FLACS). SETTING: Centre For Sight Group of Eye Hospitals, a chain of tertiary eyecare hospitals in India. DESIGN: Prospective interventional case series. METHODS: The study included eyes with PPCs undergoing FLACS using the CATALYS femtosecond platform. Real-time OCT guidance was used to image the posterior capsule (PC), which was then classified as intact or dehiscent. The femtosecond laser was used for the creation of capsulotomy, nuclear fragmentation, and corneal incisions. In all eyes, the posterior offset (distance between the posterior extent of nucleotomy and the PC) was increased to enable a thick epinuclear cushion. Intraoperative status of the PC was noted, and the specificity and the sensitivity of AS-OCT to detect a preexisting posterior capsular defect was determined. RESULTS: The cohort included 50 eyes (40 patients), in which a posterior capsular discontinuity on AS-OCT was observed in 7 eyes (14%). Five (10%) of these 7 eyes developed an intraoperative posterior capsular rent (PCR) A sensitivity and negative predictive value of 100% was noted. No case of nucleus drop was noted. CONCLUSIONS: Femtosecond laser with integrated AS-OCT is a relevant and helpful tool to detect and increase the safety in preexisting posterior capsular dehiscence, alerting the surgeon ahead of phacoemulsification.

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 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.

Visual outcomes of patients bilaterally implanted with the extended range of vision intraocular lens: A prospective study.

PURPOSE: The aim of this study was to analyze the objective and subjective visual outcomes of patients bilaterally implanted with the extended range of vision intraocular lens (EROV IOL), the Tecnis Symfony. METHODS: This was a prospective interventional case series conducted at a tertiary eye care hospital in South India. The study included patients with bilateral implantation of EROV IOLs. The uncorrected and corrected visual acuity for distance, intermediate, and near vision was recorded at 6 weeks and 6 months' postoperative visit. A subjective questionnaire was administered to assess spectacle independence, photic phenomenon, and overall satisfaction. All data were recorded using Microsoft Excel worksheet. The analyses were performed using SPSS for windows software. RESULTS: Our study included fifty patients with bilateral implantation of EROV IOLs. The mean age was 59.84 ± 11.68 years. The mean uncorrected binocular distance, intermediate, and near visual acuity (in standard decimal equivalent) was 0.89,0.99 and 0.99 respectively, at 6 months' postoperative visit. Ninety-six percent of the patients did not require spectacles for distance and 98% of the patients were free from spectacles for intermediate and near vision. 94% of our patients perceived no or minimal photic phenomena such as glare and halos. The mean subjective patient satisfaction score (out of 10) for distance, intermediate, and near was 9, 10, and 9, respectively. CONCLUSION: The EROV IOLs demonstrated high levels of spectacle independence for distance, intermediate, and near vision. The incidence of photic phenomena observed was minimal with a high level of patient satisfaction.

Optimizing outcomes with multifocal intraocular lenses.

Modern day cataract surgery is evolving from a visual restorative to a refractive procedure. The advent of multifocal intraocular lenses (MFIOLs) allows greater spectacle independence and increased quality of life postoperatively. Since the inception in 1980s, MFIOLs have undergone various technical advancements including trifocal and extended depth of vision implants more recently. A thorough preoperative workup including the patients' visual needs and inherent ocular anatomy allows us to achieve superior outcomes. This review offers a comprehensive overview of the various types of MFIOLs and principles of optimizing outcomes through a comprehensive preoperative screening and management of postoperative complications.

Recent advances in corneal collagen cross-linking.

Corneal collagen cross-linking has become the preferred modality of treatment for corneal ectasia since its inception in late 1990s. Numerous studies have demonstrated the safety and efficacy of the conventional protocol. Our understanding of the cross-linking process is ever evolving, with its wide implications in the form of accelerated and pulsed protocols. Newer advancements in technology include various riboflavin formulations and the ability to deliver higher fluence protocols with customised irradiation patterns. A greater degree of customisation is likely the path forward, which will aim at achieving refractive improvements along with disease stability. The use of cross-linking for myopic correction is another avenue under exploration. Combination of half fluence cross-linking with refractive correction for high errors to prevent post LASIK regression is gaining interest. This review aims to highlight the various advancements in the cross-linking technology and its clinical applications.