Comparative evaluation of biomechanical changes and aberration profile following accelerated collagen cross-linking using hypo-osmolar and iso-osmolar riboflavin: A prospective study.

PURPOSE: To compare the changes encountered in corneal biomechanics and aberration profile following accelerated corneal collagen cross-linking (CXL) using hypo-osmolar and iso-osmolar riboflavin in corneal thicknesses of <400 and >400 microns, respectively. METHODS: This is a prospective, interventional, comparative study involving 100 eyes of 75 patients with progressive keratoconus. Eyes were divided into two groups based on corneal thickness: group 1 included eyes with a corneal thickness of <400 microns who underwent hypo-osmolar CXL, and group 2 included eyes with a corneal thickness of >400 microns who underwent iso-osmolar CXL. Corneal biomechanical and aberration profiles were evaluated and compared between groups. RESULTS: In group 1, all higher-order aberrations (HOA) except secondary astigmatism significantly decreased from baseline; however, in group 2, only coma and trefoil decreased. The corneal resistance factor and corneal hysteresis significantly improved in both groups, which was significantly greater in group 2 than in group 1. The change in inverse radius, deformation amplitude, and tomographic biomechanical index was significantly improved in group 2 as compared to group 1. CONCLUSION: Improvement in corrected distance visual acuity and decrease in HOA were significantly better in the hypo-osmolar CXL group; however, the improvement in biomechanical strength of the cornea was significantly better in the iso-osmolar group.

Immunopathogenesis of corneal graft rejection.

The most common cause of corneal graft failure is corneal graft rejection (CGR). Although cornea is one of the immune-privileged sites, it can still get a rejection episode due to a breach in its natural protective mechanism. Both anatomical and structural properties of cornea and anterior chamber contribute toward its immune tolerance. Clinically, every layer of the transplanted cornea can get a rejection episode. A proper understanding of immunopathogenesis will help in understanding the various mechanism of CGR and the development of newer strategies for the prevention and management of such cases.

Comparison of Pre-Descemet Endothelial Keratoplasty and Descemet Membrane Endothelial Keratoplasty in Endothelial Decompensation.

PURPOSE: The purpose of this study was to compare the outcomes of pre-Descemet endothelial keratoplasty (PDEK) and Descemet membrane endothelial keratoplasty (DMEK) in cases of endothelial decompensation. METHODS: This was a prospective, randomized, interventional study conducted at a tertiary eye hospital in North India. Thirty eyes of 28 patients with corneal decompensation were randomly subjected to PDEK (n = 15 eyes) and DMEK (n = 15 eyes). Preoperative demographic details, surgical indications, uncorrected distance visual acuity, corrected distance visual acuity, contrast sensitivity, anterior and posterior segment details, intraocular pressure, central corneal thickness, endothelial cell count, and corneal aberrometry tracing on wavefront analysis were recorded. Patients were followed up for 6 months postsurgery. Visual and graft survival outcomes were assessed. RESULTS: Intraoperatively, a surgeon reported better ease of preparation and intracameral handling with PDEK grafts. Both groups showed comparable improvement in visual acuity, contrast, and high-order aberrations. A decrease in central corneal thickness was significantly higher in DMEK (196 ± 26 vs. 140 ± 14 µm) patients. DMEK grafts were significantly thinner than PDEK grafts at the 6-month follow-up (16 ± 2.17 vs. 27.2 ± 1.93 µm). Endothelial cell loss (35% in DMEK vs. 33.4% in PDEK, P = 0.48) and rise of intraocular pressure (from 15.33 ± 2.85 mm Hg to 15.53 ± 2.2 mm Hg in the DMEK group vs. from 14.6 ± 1.99 mm Hg to 16.2 ± 1.43 mm Hg in the PDEK group) were comparable. Rebubbling rates were higher in the DMEK group (3/15, 20%) compared with the PDEK group (1/15, 6.66%; P = 0.165). CONCLUSIONS: DMEK and PDEK were comparable for both quantitative and qualitative visual outcomes and anatomically for graft survival at the 6-month follow-up.

Premium intraocular lenses in children.

Multifocal and toric intraocular lenses (IOLs) or the so-called premium IOLs are currently widely used in adult patients as a one-step refractive solution following cataract surgery. However, the decision to implant a premium IOL in a pediatric patient involves multiple factors affecting the child's visual development and is associated with several dilemmas and surgical challenges. The purpose of this review is to summarize these factors and analyse the influence of each of them on the visual outcomes following premium IOL implantation. A review of literature was conducted using the relevant keywords from various databases until 31st January 2022. All pertinent studies with multifocal or toric IOL implantation in children were reviewed, and relevant articles were studied in detail for age, IOL power calculation, visual outcomes (refractive outcomes, contrast sensitivity and stereopsis) and complications such as dysphotic phenomena and others. A total of 17 relevant studies (10 case series/interventional studies and 7 case reports) on the subject were included. All studies showed a favourable refractive outcome; however, the data available was significantly less. Studies with earlier models of multifocal IOLs showed a higher incidence of IOL decentration and posterior capsule opacification; however, more recent studies with newer IOL models showed much better safety profiles. Toric IOLs showed promising results in all the studies evaluated. Premium IOLs have shown promising results in the pediatric age group. However, their long-term outcomes specifically concerning refractive shift, capsular contraction and role in the management of amblyopia needs to be explored further.

A novel low-cost indigenous goggle design for oxygen delivery in oxygen supplemented accelerated corneal collagen cross-linking.

PURPOSE: Our study aims to describe a novel low-cost indigenous design of goggles for delivery of oxygen during oxygen supplemented accelerated corneal collagen cross-linking (CXL). METHODS: The goggles were prepared by modifying the safety goggles available in personal protective equipment (PPE) kit. The goggle has two side openings covered with plugs. One plug was removed to insert a tubing for oxygen delivery at a rate of 5 litres/minute. A 20-gauge intravenous cannula was introduced from superior aspect of the goggle for measuring oxygen saturation in periocular environment. RESULTS: The procedure could be successfully performed without any intraoperative difficulty with an oxygen concentration between 80-90% throughout procedure. The time to achieve maximum concentration after switching on oxygen supply was between 30-60 s. None of our patients complained of any discomfort due to goggles. There was no mechanical interference of the goggles with the UV delivery system and a focused UV light could be delivered. The opening in goggles allowed for uninterrupted alignment and centration of UV light at the corneal level. The effective cost of the goggles, canula and tubing amounted to 400INR (5.50USD). There was no distortion, kinking or slippage of the tubing allowing for uninterrupted oxygen flow. These goggles could be sterilized multiple times using plasma sterilization. CONCLUSION: The current modified cost-effective goggle design could be an effective alternative to the currently available oxygen delivery goggles, especially in a low resource setting.

Hitch suture assisted tuck in Tenon's Patch Graft for management of Corneal Perforations.

PURPOSE: To describe a novel modification of tuck-in Tenon's patch graft (TPG) using temporary horizontal mattress sutures and fibrin glue to hitch the graft in the management of corneal perforations. DESIGN: Ambispective interventional case series. METHODS: Modified technique of autologous TPG was used to seal corneal perforations measuring 3-5 mm, using horizontal mattress sutures to hitch the graft in a lamellar pocket, followed by application of fibrin glue. The horizontal mattress sutures were removed after the reformation of the anterior chamber. The primary outcome measure was a well formed anterior chamber in the post-operative period and the secondary outcome was epithelization time. RESULTS: The surgery was performed in 22 eyes. The mean age was 43.86 ± 16.02 (26-66) years, with 14 males and eight females. The etiologies of corneal perforation included dry eye (n = 10), neurotrophic keratitis (n = 6), trauma (n = 2), chemical injury (n = 2) and exposure (n = 2). The mean size of the perforation with the thinned-out area was 4.3 mm (range 3-5 mm). The mean duration of epithelialization was 14.31 ± 2.63 days (7-21 days). No intraoperative complications were observed. All eyes had a well-formed anterior chamber in the immediate postoperative period. Postoperatively, two eyes had graft pseudoectasia due to a thick graft and supra tenon haemorrhage each; one eye each had graft thinning with the formation of pseudopterygium and graft melting. CONCLUSION: Tenon's patch graft, along with the use of temporary horizontal mattress sutures and fibrin glue, is an effective modification of the technique for managing corneal perforations measuring 3-5 mm.

Animal and cadaver human eyes for residents' surgical training in ophthalmology.

In ophthalmology residency programs surgical training plays a vital role in creating confident and skillful surgeons. As almost all ophthalmic surgery needs microscope training, creating a well-taught environment for hand-eye coordination, ocular tissue handling, and anticipation of complications is essential. Wet lab training with animal or cadaver human eyes offers diverse possibilities. We conducted a thorough literature search on various databases to identify the existing literature on wet labs. The results revealed constructive efforts for training novice surgeons in all surgical ophthalmology subspecialties. Wet lab models were initially used only to practice cataract surgery; however, now various complex ocular procedures can be practiced. Ocular surface, corneal, iris, lenticular, scleral, vitreoretinal, extraocular, eyelid, and other adnexal surgeries were reproduced and mastered in many ways. Importantly, with repeated surgical practice, residents gained an increasing level of confidence with enhanced surgical accuracy. In addition, we propose a few novel techniques of various other procedures.

Long-term Outcomes of Fibrin Glue-Assisted Intrascleral Haptic Fixation of Posterior Chamber Intraocular Lenses in Children.

OBJECTIVES: To evaluate the long-term outcomes of intrascleral haptic fixation of posterior chamber intraocular lens (PCIOL) with fibrin glue in children. METHODS: This is a retrospective case study conducted in a tertiary eye institute in North India. A total of 118 eyes of 82 children who underwent glued intrascleral haptic fixation of PCIOLs were retrospectively analyzed. Detailed analysis of the indication for surgery and ocular and systemic associations was performed. The outcome measures included intraoperative complications, final visual and refractive outcomes, and postoperative complications. RESULTS: The mean age of the patients was 10.16±3.94 years. Fifty-one patients (62.2%) were male and 31 (37.8%) were female. The mean follow-up period was 31.28±13.22 months. The mean preoperative corrected distance visual acuity was 1.18±0.63 Logarithm of Mean angle of resolution (logMAR) which improved to 0.60±0.58 logMAR postoperatively at 6 weeks (P<0.001). The mean preoperative and 6 weeks postoperative endothelial cell density were 3,176.08±318.6 and 2,936±289.9 cells/mm2, respectively (P=0.23). In the immediate postoperative period, corneal edema (19 eyes; 16.1%), decentered IOL/tilt (3 eyes; 2.54%), vitreous hemorrhage (3 eyes; 2.54%), optic capture (4 eyes; 3.38%), and hypotony (2 eyes; 1.69%) were seen. In the late postoperative period (>6 weeks), retinal detachment was observed in two eyes that had associated Marfan syndrome. Cystoid macular edema was seen in four eyes (3.38%), and glaucoma was seen in five eyes (4.23%). CONCLUSIONS: Fibrin glue-assisted intrascleral haptic fixation of a PCIOL is a safe and effective method to manage aphakia with inadequate capsular support in children.

Microscope Integrated Optical Coherence Tomography Guided Descemet Stripping Automated Endothelial Keratoplasty in Congenital Hereditary Endothelial Dystrophy.

PURPOSE: To describe the outcomes of descemet stripping automated endothelial keratoplasty (DSAEK) in congenital hereditary endothelial dystrophy (CHED) and to evaluate the role of microscope integrated optical coherence tomography (Mi-OCT) during the surgery. DESIGN: Retrospective data analysis. METHODS: A retrospective study from the medical records of all those patients who were diagnosed with CHED and underwent DSAEK at our centre from 2015 were evaluated. All patients underwent Mi-OCT-guided standard DSAEK procedure. Intra-operative difficulties, visual outcomes and graft survival were recorded. RESULTS: A total of 48 eyes of 29 patients with a mean age of 9.87 ± 8.2 years and mean follow-up of 17.3 months were evaluated. Thirty-nine eyes underwent primary DSAEK and 9 eyes underwent PKP. Three eyes who underwent PKP had failed graft for which they underwent DSAEK. The mean preoperative Snellen's visual acuity was 1.71 ± 0.66 and the mean preoperative central corneal thickness was 1.10 ± 0.174 mm. Intraoperatively, all the grafts were attached which was confirmed using Mi-OCT. Graft detachment was seen in the immediate postoperative period in 10.4% (4 eyes) of primary DSAEK, out of which DM scoring was not performed in 2 eyes. Following DSAEK, cornea cleared at four-week follow-up in 89.7% eyes and in all the eyes the cornea cleared at six-week follow-up. CONCLUSION: Primary DSAEK could be a preferred option over PKP for CHED with early presentation and in those eyes with failed primary PKP. Mi-OCT is a very useful tool in these eyes for various intraoperative procedures, thereby improving the outcomes of the procedure.

Intrascleral haptic fixation for haptic exposure after Yamane technique.

A 55-year-old patient presented with exposure of both the haptics beyond the conjunctiva of the scleral fixated multipiece intraocular lens (IOL). Two diagonally opposite scleral pockets were created, and the exposed haptics was redirected and repositioned aseptically into these pockets to facilitate intrascleral fixation. Herein, we report a simple rescue method for management of exposed haptic after Yamane technique of scleral fixated IOL.

Management of small perforated corneal ulcers: Training model in mammalian eye to enhance surgical skills of residents.

PURPOSE: To demonstrate a training technique on the mammalian eye for optimum Cyanoacrylate Tissue adhesive application in cases of perforated corneal ulcers. METHODS: A full-thickness defect simulating a perforation was created on the goat's eye cornea to teach the technique of cyanoacrylate glue application in cases of corneal perforations to novice surgeons. RESULTS: This training model on the mammalian eye was tested by 10 residents at our centre. All the 10 candidates involved in our series were newly joined Cornea fellows with proficient skill in cataract surgeries and minor ophthalmic procedures such as suture removal, chalazion excision, pterygium removal and administration of an intravitreal injection. None of the candidates had prior experience of corneal surgeries. Each resident made an average of 4.4 attempts to seal the corneal defect, obtain a regular corneal surface and form the anterior chamber. CONCLUSION: This training model helps in mastering one of the skills of corneal surgeries.

Posterior Chamber Phakic Intraocular Lens Implantation for Refractive Correction in Corneal Ectatic Disorders: A Review.

PURPOSE: To summarize the indications and outcomes of posterior chamber phakic intraocular lens (PIOL) implantation in corneal ectasias including keratoconus, pellucid marginal degeneration (PMD), post-refractive surgery, and post-keratoplasty ectasias. METHODS: A review of the literature was conducted using the relevant keywords from various databases up to August 15, 2020. All pertinent studies were reviewed, and the relevant articles were studied in detail for efficacy, stability, predictability, and safety outcomes. In addition, visual quality, corneal biomechanical outcomes, complications, the role of posterior chamber PIOL in combination treatment, and comparison of posterior chamber PIOL with other PIOLs for ectasias were also evaluated. RESULTS: A total of 30 relevant studies (13 prospective, 13 retrospective, 4 case reports) on the subject were studied and summarized. All studies showed a favorable refractive outcome. Quality of vision remained unaffected and no significant complications were reported in any of the studies. CONCLUSIONS: Posterior chamber PIOLs represent a viable option in the treatment of mild to moderate and stable corneal ectasia in patients with contact lens intolerance who have low irregular astigmatism, a clear central cornea, and good preoperative corrected distance visual acuity. [J Refract Surg. 2021;37(5):351-359.].

Novel technique of tetra trephination for elliptical-shaped tectonic patch grafts in peripheral sterile keratolysis.

PURPOSE: To describe a novel technique of tectonic patch grafts for elliptical-shaped peripheral sterile keratolysis with iris prolapse. METHODS: We performed a full thickness corneo-scleral patch graft in five eyes of five patients with elliptical-shaped peripheral sterile keratolysis with perforation and iris tissue prolapse. In this technique, four disposable trephines with predetermined diameter were employed to fashion both the host and the donor without any free-hand dissection. An intact anatomical integrity of the globe without the need for any repeat tectonic measures was considered as a successful outcome. RESULTS: The mean age was 34.2 ± 10.2 years (18-45). The mean total surgical time and donor preparation time was 94.4 ± 7.12 min and 7.6 ± 1.14 min, respectively. The intraoperative course was uneventful in all cases and all eyes had a well-maintained corneal integrity till 6 months follow up. CONCLUSION: We describe a simple, reproducible, and time-saving technique of performing elliptical shaped corneoscleral patch grafts for peripheral corneal perforations with iris prolapse.

Bilateral liquefactive corneal necrosis: a rare and devastating complication of vitamin A deficiency in the adult.

A 34year-old man presented with diminution of vision, pain and whitish opacity in both eyes (right eye followed by left eye) since 1 week. He is a known case of chronic alcoholic abuse. He had multiple episodes of haemoptysis in the past. On general physical examination, he was severely malnourished with multiple oral ulcers. Visual acuity at presentation was light perception in both eyes with projection of rays accurate in all quadrants. Slit-lamp biomicroscopy revealed bilateral total corneal melt with diffuse conjunctival congestion. Corneal scrapings and blood investigations were done and he was started on empirical topical and systemic therapy followed by surgical intervention, with large corneal grafts in both the eyes (right eye followed by left eye) with 1 day interval. The visual gain in both the eyes were 20/400 at first postoperative day. The right eye developed severe fibrinous reaction on the second postoperative day which resolved with topical antibiotics, topical steroids and systemic steroids. The patient was followed up via telemedicine (due to COVID-19 outbreak) and he is able to carry out his daily routine work independently.

Suturing large therapeutic corneal grafts based on donor size: A simplified technique for the novice corneal surgeon.

PURPOSE: We describe a simple technique for achieving radial and equally spaced sutures by novice corneal surgeon in cases of large penetrating keratoplasties. METHOD: A simple mathematical equation was derived for precise calculation of spacing between interrupted sutures in large grafts (n = 50). The ubiquitous and easily available Castroviejo calipers were used to mark the donor cornea according to the derived formula. Interrupted sutures were passed over the pre-marked points and tied. Radiality was assessed in the post-operative period. RESULTS: A total of 50 eyes undergoing therapeutic keratoplasty with graft size between 9 and 12 mm were enrolled. Equally spaced and radially aligned sutures were achieved in all cases postoperatively with watertight apposition of the graft host junction using our simple technique. CONCLUSION: The Castroviejo caliper can be effectively used for equidistant spacing of interrupted sutures in large therapeutic grafts by a novice surgeon thereby simplifying the procedure and reducing the surgical time.