Kuragel: A biomimetic hydrogel scaffold designed to promote corneal regeneration.

Cornea-related injuries are the most common cause of blindness worldwide. Transplantation remains the primary approach for addressing corneal blindness, though the demand for donor corneas outmatches the supply by millions. Tissue adhesives employed to seal corneal wounds have shown inefficient healing and incomplete vision restoration. We have developed a biodegradable hydrogel - Kuragel, with the ability to promote corneal regeneration. Functionalized gelatin and hyaluronic acid form photo-crosslinkable hydrogel with transparency and compressive modulus similar to healthy human cornea. Kuragel composition was tuned to achieve sufficient adhesive strength for sutureless integration to host tissue, with minimal swelling post-administration. Studies in the New Zealand rabbit mechanical injury model affecting corneal epithelium and stroma demonstrate that Kuragel efficiently promotes re-epithelialization within 1 month of administration, while stroma and sub-basal nerve plexus regenerate within 3 months. We propose Kuragel as a regenerative treatment for patients suffering from corneal defects including thinning, by restoration of transparency and thickness.

Chemical (Alkali) Burn-Induced Neurotrophic Keratitis Model in New Zealand Rabbit Investigated Using Medical Clinical Readouts and In Vivo Confocal Microscopy (IVCM).

PURPOSE: Chemical eye injury is an acute emergency that can result in vision loss. Neurotrophic keratitis (NK) is the most common long-term manifestation of chemical injury. NK due to alkali burn affects ocular surface health and is one of its most common causes. Here, we established a rabbit model of corneal alkali burns to evaluate the severity of NK-associated changes. MATERIAL METHODS: Alkali burns were induced in NZ rabbits by treating the cornea with (i) a 5 mm circular filter paper soaked in 0.75 N NaOH for 10 s (Mild NK) and (ii) trephination using a guarded trephine (5 mm diameter and 150-micron depth), followed by alkali burn, with a 5 mm circular filter paper soaked in 0.75 N NaOH for 10 s (a severe form of NK). Immediately after, the cornea was rinsed with 10 mL of normal saline to remove traces of NaOH. Clinical features were evaluated on Day 0, Day 1, Day 7, Day 15, and Day 21 post-alkali burn using a slit lamp, Pentacam, and anterior segment optical coherence tomography (AS-OCT). NK-like changes in epithelium, sub-basal nerve plexus, and stroma were observed using in vivo confocal microscopy (IVCM), and corneal sensation were measured using an aesthesiometer post alkali injury. After 21 days, pro-inflammatory cytokines were evaluated for inflammation through ELISA. RESULTS: Trephination followed by alkali burn resulted in the loss of epithelial layers (manifested using fluorescein stain), extensive edema, and increased corneal thickness (550 µm compared to 380 µm thickness of control) evaluated through AS-OCT and increased opacity score in alkali-treated rabbit (80 compared to 16 controls). IVCM images showed complete loss of nerve fibers, which failed to regenerate over 30 days, and loss of corneal sensation-conditions associated with NK. Cytokines evaluation of IL6, VEGF, and MMP9 indicated an increased angiogenic and pro-inflammatory milieu compared to the milder form of NK and the control. DISCUSSION: Using clinical parameters, we demonstrated that the alkali-treated rabbit model depicts features of NK. Using IVCM in the NaOH burn animal model, we demonstrated a complete loss of nerve fibers with poor self-healing capability associated with sub-basal nerve degeneration and compromised corneal sensation. This pre-clinical rabbit model has implications for future pre-clinical research in neurotrophic keratitis.

Dealing With Pericylindrical Melts in Keratoprosthesis: Tenon Patch Graft to the Rescue.

PURPOSE: The aim of this study was to describe the outcomes of autologous Tenon patch graft in the management of Auro keratoprosthesis-related pericylindrical corneal melt. METHODS: We report 3 cases of sterile pericylindrical corneal melt in patients with Auro keratoprosthesis implantation after a mean duration of 5 years (1.5-8 years). Case 1 was a patient with severe graft-versus-host disease. Cases 2 and 3 were cases of chemical injury.All these cases of sterile pericylindrical corneal melt (4-6 mm) underwent autologous Tenon patch graft. The technique included freshening of the edges around the melt, followed by measuring the size of the defect. A Tenon graft harvested from the patient's own eye was used to seal the defect and act as a scaffold. The Tenon patch graft was spread over the melt and held in place by the application of fibrin glue and/or interrupted 10-0 nylon sutures. A bandage contact lens was then placed on the eye. RESULTS: Tenon patch graft was well taken in all patients. The mean duration of epithelial healing was 1 month. Globe integrity was well maintained with no postoperative complications at a mean follow-up duration of 12 months (6-18 months). CONCLUSIONS: Corneal melt is one of the most dreaded complications of KPro because its occurrence could threaten visual prognosis and globe integrity. Autologous Tenon patch is a simple yet innovative and effective option to steer such eyes away from potentially dreadful complications.

Visual outcome and postoperative complications of cataract surgery in patients with ocular surface disorders.

PURPOSE: To determine the visual outcome and postoperative complications of cataract surgery in patients with ocular surface disorders (OSDs). SETTING: Tertiary eyecare center in North India. DESIGN: Retrospective observational study. METHODS: Patients with various OSDs with stabilized ocular surfaces who underwent cataract surgery during this period and had a minimum postoperative follow-up of 6 weeks were included. The primary outcome measures were postoperative corrected distance visual acuity (CDVA) at 6 weeks, best CDVA achieved, and postoperative complications. RESULTS: The study included 20 men and 24 women. A total of 55 eyes were evaluated: Stevens-Johnson syndrome (SJS) 35 eyes, ocular cicatricial pemphigoid (OCP) 4 eyes, 8 eyes with dry eye disease (DED), 6 eyes with chemical injury and 2 eyes with vernal keratoconjunctivitis (VKC). The mean duration of OSD was 33.9 ± 52.17 months. The median preoperative CDVA was 2.0 (interquartile range [IQR], 1.45 to 2.0). The median CDVA ever achieved was 0.50 (IQR, 0.18 to 1.45) at 2 months and the median CDVA at 6 weeks was 0.6 (IQR, 0.3 to 1.5). Maximum improvement in CDVA was noted in patients with DED and SJS and the least in OCP. Phacoemulsification was performed in 47.27% eyes with intraoperative complications noted in 9% eyes. Postoperative surface complications occurred in 12 (21.82%) eyes. Other postoperative complications occurred in 9 (16%) eyes. CONCLUSIONS: Cataract surgery outcome can be visually rewarding in patients with OSDs provided ocular surface integrity is adequately maintained preoperatively and postoperatively.

Krupple-like factor 4 (KLF4) methylation signature in host cell in active viral keratitis with epithelial manifestation.

HSV1 presents as epithelial or stromal keratitis or keratouveitis and can lead to sight-threatening complications. KLF4, a critical transcription factor, and regulator of cell growth and differentiation, is essential in corneal epithelium stratification and homeostasis. Here, we want to understand the epigenetic modification specifically the methylation status of KLF4 in epithelium samples of HSV1 keratitis patients. After obtaining consent, epithelial scrapes were collected from 7 patients with clinically diagnosed HSV1 keratitis and 7 control samples (patients undergoing photorefractive keratectomy). Genomic DNA was isolated from the collected samples using the Qiagen DNeasy Kit. Subsequently, bisulfite modification was performed. The bisulphite-modified DNA was then subjected to PCR amplification using specific primers designed to target the KLF4, ACTB gene region, allowing for the amplification of methylated and unmethylated DNA sequences. The amplified DNA products were separated and visualized on a 3% agarose gel. KLF4 hypermethylation was found in 6 out of 7 (85.71%) eyes with viral keratitis, while 1 eye showed hypomethylation compared to PRK samples. Out of these 6, there were 2 each of epithelial dendritic keratitis, epithelial geographical keratitis, and neurotrophic keratitis. The patient with hypomethylated KLF4 had a recurrent case of HSV1 keratitis with multiple dendrites and associated vesicular lesions of the lip along with a history of fever. KLF4 hypermethylation in most viral keratitis cases indicated the under functioning of KLF4 and could indicate a potential association between KLF4 hypermethylation and the development or progression of HSV1 keratitis.

Bridging the gap: The promise of corneal bioengineering and regeneration.

In recent years, significant advances in tissue engineering and regenerative medicine have led to innovative approaches in addressing the various challenges associated with corneal transplants using bioengineered corneas. This mini-review aims to introduce the general ophthalmologist to the concept and technique of bioengineered cornea and provide an overview of the developments so far and an insight into the future direction. By summarizing the latest research and current limitations, we aim to highlight their potential for the future in ultimately contributing to vision restoration.

Prolonged Inflammation and Infectious Changes in the Corneal Epithelium Are Associated with Persistent Epithelial Defect (PED).

Purpose: Failure of rapid re-epithelialization within 10-14 days after corneal injury, even with standard supportive treatment, is referred to as persistent corneal epithelial (CE) defect (PED). Though an array of genes regulates reepithelization, their mechanisms are poorly understood. We sought to understand the network of genes driving the re-epithelialization in PED. Method: After obtaining informed consent, patients underwent an ophthalmic examination. Epithelial scrapes and tears samples of six PED patients and six individuals (control) undergoing photorefractive keratectomy (PRK) were collected. RNA isolation and quantification were performed using either the epithelial scrape taken from PED patients or from HCLE cells treated with control tears or tears of PED patients. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression of a few important genes in CE homeostasis, inflammation, and cell-cell communication, viz., Kruppel-like factor 4 (KLF4), GPX4, IL6, TNFα, STING, IL8, desmoglein, and E-cadherin, among others. Their expressions were normalized with their respective housekeeping genes and fold changes were recorded. KLF4 localization and MMPs activity was carried out via immunofluorescence and zymography, respectively. Results: KLF4, a transcription factor important for CE homeostasis, was upregulated in tears-treated HCLE cells and downregulated in PED patients compared to the healthy PRK group. Cell-cell communication genes were also upregulated in tears-treated cells, whereas they were downregulated in the PED tissue group. Genes involved in proinflammation (IL6, 282-fold; TNFα, 43-fold; IL8, 4.2-fold) were highly upregulated in both conditions. MMP9 activity increased upon tears treatment. Conclusions: This study suggests that tears create an acute proinflammatory milieu driving the PED disease pathology, whereas the PED patients scrapes are an indicator of the chronic stage of the disease. Interferons, pro-inflammatory genes, and their pathways are involved in PED, which can be a potential target for inducing epithelialization of the cornea.

New horizons in aniridia management: Clinical insights and therapeutic advances.

Congenital aniridia is a rare genetic eye disorder characterized by the complete or partial absence of the iris from birth. Various theories and animal models have been proposed to understand and explain the pathogenesis of aniridia. In the majority of cases, aniridia is caused by a mutation in the PAX6 gene, which affects multiple structures within the eye. Treating these ocular complications is challenging and carries a high risk of side effects. However, emerging approaches for the treatment of aniridia-associated keratopathy, iris abnormalities, cataract abnormalities, and foveal hypoplasia show promise for improved outcomes. Genetic counseling plays a very important role to make informed choices. We also provide an overview of the newer diagnostic and therapeutic approaches such as next generation sequencing, gene therapy, in vivo silencing, and miRNA modulation.

Clinical and molecular aspects of congenital aniridia - A review of current concepts.

Congenital aniridia is a pan ocular disorder characterized by partial or total loss of iris tissue as the defining feature. Classic aniridia, however, has a spectrum of ocular findings, including foveal hypoplasia, optic nerve hypoplasia, nystagmus, late-onset cataract, glaucoma, and keratopathy. The latter three are reasons for further visual compromise in such patients. This entity is often due to mutations in the PAX6 (Paired box protein Pax-6) gene. Recently, aniridia-like phenotypes have been reported due to non-PAX6 mutations as in PITX2, FOXC1, FOXD3, TRIM44, and CYP1B1 as well wherein there is an overlap of aniridia, such as iris defects with congenital glaucoma or anterior segment dysgenesis. In this review, we describe the various clinical features of classic aniridia, the comorbidities and their management, the mutation spectrum of the genes involved, genotype-phenotype correlation of PAX6 and non-PAX6 mutations, and the genetic testing plan. The various systemic associations and their implications in screening and genetic testing have been discussed. Finally, the future course of aniridia treatment in the form of drugs (such as ataluren) and targeted gene therapy has been discussed.

Effect of timolol maleate (0.5%) in the management of myopic regression post laser-assisted in-situ keratomileusis: Clinical and topographical outcomes.

PURPOSE: The aim of this study was to analyze the effect of timolol maleate (0.5%) eye drops in the treatment of myopic regression after laser-assisted in-situ keratomileusis (LASIK). METHODS: The study was conducted at a tertiary care eye hospital in north India between April 2017 & March 2018 as a prospective interventional study. Patients who underwent uneventful myopic LASIK with hansatome mechanical keratome and presented with regression were included in the study. Baseline demographic characteristics, time to presentation with regression best-corrected visual acuity (BCVA), refraction, intraocular pressure, central corneal thickness and keratometry were recorded at baseline and at each follow-up visit. The enrolled patients were prescribed timolol maleate (0.5%) eyedrops twice daily. They were followed up every month till 3 months on timolol maleate (0.5%) eyedrops and at 6 months post stopping the treatment. RESULTS: Twenty-nine eyes of 15 patients were enrolled in the study. Mean pre LASIK spherical equivalent (SE) was - 7.48 ± 2.9 Diopters (Range-3.125 to -11.75 Diopters) and mean regression spherical equivalent was -1.02 ± 1.1 Diopters. There was a decrease in mean SE from presentation (intervention start point) up to 6 months follow-up (-1.34 ± 0.89 to -0.30 ± 0.29 Diopters). While posterior corneal curvature (K1 and K2 Back) changed significantly over treatment period (P = 0.0029, P = 0.0024 respectively), changes in anterior corneal curvature (K1 and K2 Front) were not significant (P = 0.05, P = 0.06 respectively). Central corneal thickness (CCT) and intraocular pressure (IOP) did not change significantly over treatment course. CONCLUSION: Timolol maleate (0.5%) eyedrop is an effective modality for the treatment of refractive regression post LASIK circumventing the need for laser re-treatment in such patients. The most probable mechanism is reversal of the anterior bowing of the cornea in response to intraocular pressure changes.

Demographic details, risk factors, microbiological profile, and clinical outcomes of pediatric infectious keratitis cases in North India.

Purpose: To study the demographic details, risk factors, microbiological profile, and clinical outcomes of pediatric infectious keratitis cases in North India. Methods: This retrospective case series included review of medical records of pediatric patients (0-16 years) diagnosed with infectious keratitis in a tertiary care center of North India during December 2011 to January 2017 was done. Demographic details, predisposing factors, microbiological investigations, and clinical outcomes were analyzed. Results: In this time period, 104 eyes of 104 children had a diagnosis of infectious keratitis. Culture was obtained for all 104 eyes and was positive in eighty eight eyes (84.2%). The most common causative factor was trauma, seen in 77 eyes (74%). Bacteria was the most common agent isolated in culture (54.2%) followed by fungi (40.8%) and acanthamoeba (2.1%). Successful healing of the keratitis with appropriate medical treatment occurred in 84 (80.7%) eyes, while 13 (12.5%) eyes required therapeutic keratoplasty. Of the 80 eyes with documentation of both preliminary and final visual acuity, improvement of two lines was seen in 35 eyes (43.7%), stayed the same in and worsened in 17 eyes (21%). Mean time to resolution of infection on medical treatment for bacteria was 23.65 ± 4.78 days, fungi 32 ± 5.19 days, and acanthamoeba 53.67 ± 4.78 days. Conclusion: Gram positive organism is the most common etiological agent of keratitis in children in our study population which is in contrast to pediatric infective keratitis study conducted by Aruljyothi et al. in South India (2011--2013). Though less in number than bacterial keratitis, fungus also remains an important causative agent. Along with early diagnosis and immediate medical intervention, it is important to identify regional profile of organisms and risk factors for good visual and anatomical outcome.

Nocardia infection following intraocular surgery: Report of seven cases from a tertiary eye hospital.

PURPOSE: To study the outcome of ocular nocardiosis following intraocular surgery. MATERIALS AND METHODS: A retrospective review of medical records of all postoperative cases of culture proven Nocardia infection over a period of 3 years, from October 2010 to September 2013, was performed. Microbiological analysis was performed for all cases and included smears and cultures. Fortified 2% amikacin eye drops were the mainstay of treatment. Surgical intervention was performed in case of nonresponse to medical therapy or suspected endophthalmitis. RESULTS: Seven cases of culture proven Nocardia infection were seen. All cases had been operated in a hospital surgical facility. Six followed phacoemulsification, and one followed a secondary intraocular lens implantation. Four patients were part of a cluster infection. The mean duration between the primary surgical procedure and presentation was 16.14 ± 9.82 days. Five patients had infiltrates at the site of the surgical incision. One each had endophthalmitis and panophthalmitis. Six eyes required surgical intervention. Infection was seen to resolve in four eyes. Two eyes went into phthisis, and one was eviscerated. Only two of the six eyes, where in surgical intervention was performed early, obtained a final visual acuity of 20/60. CONCLUSION: Early surgical intervention, before the involvement of the anterior chamber, may help preserve the anatomic and functional integrity of the eye.

Clinical efficacy of oral and topical acyclovir in herpes simplex virus stromal necrotizing keratitis.

PURPOSE: To evaluate the efficacy of systemic and topical antiviral therapy in the treatment of active herpes simplex virus (HSV) necrotizing stromal keratitis (NSK). DESIGN: Prospective interventional case series. METHODOLOGY: Patients with a diagnosis of HSV NSK based on history and clinical findings were enrolled in the study. A standard protocol was used for microbiologic investigations. Ten weeks regime of systemic acyclovir and 2 weeks of topical acyclovir was given. Complete ophthalmic examination was performed at every visit. Outcome measures were a reduction in the area of infiltration and improvement in visual acuity. RESULTS: Fifteen patients were enrolled in the study. The mean age of presentation was 51.53 years. The duration of symptoms at presentation ranged from 2 to 8 weeks. HSV1 DNA polymerase chain reaction was positive in 70% cases of those tested. Area of infiltration at trial entry and at the end of 2 weeks of antiviral treatment reduced significantly (P = 0.007). All patients showed a complete resolution of keratitis at the end of study. CONCLUSION: Topical and systemic acyclovir for treatment of NSK facilitates healing of ulceration. Topical steroids after initial antiviral therapy are safe and decreases inflammation and improve visual recovery. Early initiation of therapy has better outcomes as compared to late presentations.