Use of discarded corneo-scleral rims to create cornea-like tissue.

BACKGROUND: Corneal disease is a major cause of blindness. Transplantation of cadaver-derived corneas (keratoplasty) is still the current therapy of choice; however, the global shortage of donor corneas continues to drive a search for alternatives. To this end, biosynthetic corneal substitutes have recently begun to gain importance. Here, we present a novel method for the generation of a cornea-like tissue (CLT), using corneo-scleral rims discarded after keratoplasty. METHODS AND RESULTS: Type I collagen was polymerized within the corneo-scleral rim, which functioned as a 'host' mould, directing the 'guest' collagen to polymerize into disc-shaped cornea-like material (CLM), displaying the shape, curvature, thickness, and transparency of normal cornea. This polymerization of collagen appears to derive from some morphogenetic influence exerted by the corneo-scleral rim. Once the CLM had formed naturally, we used collagen crosslinking to fortify it, and then introduced cells to generate a stratified epithelial layer to create cornea-like tissue (CLT) displaying characteristics of native cornea. Through the excision and reuse of rims, each rim turned out to be useful for the generation of multiple cornea-shaped CLTs. CONCLUSIONS: The approach effectively helps to shorten the gap between demand and supply of CLMs/CLTs for transplantation. We are exploring the surgical transplantation of this CLT into animal eyes, as keratoprostheses, as a precursor to future applications involving human eyes. It is possible to use either the CLM or CLT, for patients with varying corneal blinding diseases.

Epidemiology of Keratoconjunctivitis Across India from 2017 to 2019: A Multicentric Hospital-Based Study.

PURPOSE: Conjunctivitis is one of the most common ocular conditions in clinical practice. Human adenoviruses have been the common causative agents known to cause epidemic kerato-conjunctivitis (EKC) in India from 1996 to 2019 with a positivity range of 13.8%-65.2%. The current study was initiated to throw light on the distribution of keratoconjunctivitis causing agents across India covering a span of 3 years. METHODS: A total of 709 swabs were collected from patients in viral transport medium (VTM), and real-time PCR was done to identify agents including Adenovirus (HAdV), Enterovirus, HSV, and Chlamydia. RESULTS: 47.8% of the samples were positive for HAdV followed by HSV (3.4%), Enterovirus (2.7%), and Chlamydia (0.6%). Overall, 386 people (54.4%) tested positive for one of these infections, with Chandigarh (88.4%) and Port Blair (71.7%) showing higher positivity rate. Pre-auricular lymphadenopathy and follicles were significantly associated with increased risk of conjunctivitis. CONCLUSION: Epidemiology of keratoconjunctivitis in the current study revealed HAdV to be predominant causative agent. Knowledge gained in such epidemiological studies guide us in outbreak expectations, limit antibiotic over-prescription, and enhance disease prevention.

Tonic down-rolling and eccentric down-positioning of eyes under sevoflurane anesthesia without non-depolarizing muscle relaxant and its relationship with depth of anesthesia.

Purpose: To analyze the relationship between eccentric downward eye movement/eccentric downward eye-positioning (EDEM/EDEP) encountered in patients undergoing ophthalmic surgeries and its return to a centralized position under general anesthesia (GA) with the depth of anesthesia (DOA). Methods: Patients undergoing ophthalmic surgeries (6 months-12 years) under sevoflurane anesthesia without non-depolarizing muscle relaxant (NDMR) who witnessed a sudden tonic EDEM/EDEP were both retrospectively (R-group) and prospectively (P-group) enrolled (ambispective study). R-group included data-points after induction (AI) till the time surgery lasted while P-group compiled data both during induction (DI) and AI. DOA in terms of MAC (minimum alveolar concentration) at the time of EDEM/EDEP and centralization of eyeball and their timings were noted and compared for both AI and DI data-points. Also, vertical eccentric eye positions were scored and correlated with MAC. Results: AI data included 22 (14R+8P) events and their mean MAC of EDEM/EDEP and centralization were 1.60 ± 0.25 and 1.18 ± 0.17 respectively (p = 0.000). DI data included 62 (P) cases and its mean MAC of EDEM/EDEP and centralization was 2.19 ± 0.43 and 1.39 ± 0.26 respectively (p = 0.000). Median (IQR) eye positions during down-positioning in 84 events was -3 (-3.9 to -2.5). It was preceded by an eccentric upward drift of eyes in 10/22 (6R+4P) AI cases. A strong negative correlation was seen between DOA and eccentric eye positions (r = -0.77, p = 0.000). Conclusions: Tonic down-rolling of eyes is not uncommon in children seen without NDMR with higher depths of sevoflurane anesthesia compared to point of centralization and fluctuations in DOA should be avoided to circumvent inadvertent complications during ocular surgery.

Role of swept-source anterior segment optical coherence tomography in imaging pediatric cataract.

Purpose: To determine the morphology of pediatric cataracts and assess the status of the anterior and posterior capsules preoperatively on swept-source anterior segment optical coherence tomography (ASOCT) and compare the findings to those of intraoperative examination. Secondly, we aimed to obtain biometric measurements on ASOCT and compare them to those obtained on A-scan/optical methods. Methods: This was a prospective and observational study carried out at a tertiary care referral institute. ASOCT scans for anterior segment were obtained preoperatively for all patients, aged <8 years, scheduled for paediatric cataract surgery. The morphology of the lens and capsule and biometry were performed on ASOCT and the same were assessed intraoperatively. The main outcome measures were comparison of ASOCT findings to intraoperative findings. Results: The study included 33 eyes of 29 patients (range 3 months-8 years). The morphological characterization of cataract on ASOCT was accurate in 31/33 (94%) cases. ASOCT accurately identified fibrosis and rupture of the anterior and posterior capsules in 32/33 (97%) cases each. In 30% of eyes, ASOCT gave additional information preoperatively compared to the slit lamp. Intraclass correlation coefficient (ICC) calculation revealed a good agreement between the keratometry values obtained on ASOCT and those obtained preoperatively with a handheld/optical keratometer (ICC = 0.86, P = 0.001). Conclusion: ASOCT is a valuable tool that could provide complete preoperative information of the lens and capsule in pediatric cataract cases. In children as young as 3 months of age, intraoperative risks and surprises could be diminished. The keratometric readings are highly dependent on patient cooperation but show good agreement with the handheld/optical keratometer readings.

Perception of college-going girls towards corneal donation in North India: A latent class analysis study.

Purpose: To assess the perception of college-going girls toward corneal donation in Northern India. Methods: An online survey with a pre-structured, pre-validated questionnaire was conducted on 1721 college-going girls in Northern India. The knowledge and attitude scores were regressed, and latent class analysis was carried out. Results: The average of scores for all participants was computed individually for the knowledge questions and the attitude questions, and based on this score, total participants were divided into two groups: Better corneal donation behaviors (BCDB) and poor corneal donation behaviors. The binomial logistic regression model of knowledge domain for predicting BCDB, age of the participant, their awareness about corneal donation, and willingness to discuss eye donation among family members were found significant. Similarly, for the attitude domain, awareness about corneal donation, knowledge about hours within which ideal eye donation needs to be undertaken, and knowledge about eye donation during coronavirus disease 2019 (COVID-19) pandemic were found to be significant. Latent class analysis identified one subset of participants having poorer knowledge and attitude scores and that they were more from a rural background, were having more than first order as birth order, were belonging to SC/ST classes, had illiterate or secondary education of father and mother, and were living in rented houses. Conclusion: The findings of the study significantly contribute to devising a mechanism to improve knowledge and influencing the attitude about eye donation among the youth, especially young women, who can act as counselors and motivators for the masses as well as their own families, in the generations to come.

Tissue Adhesives for the Management of Corneal Perforations and Challenging Corneal Conditions.

Corneal perforations are ophthalmological emergencies which can have serious and detrimental consequences, if not managed timely and appropriately. These are a significant cause of ocular morbidity and can result in decreased vision, blindness, and even loss of the eye. Corneal perforations can be managed using a range of treatment approaches, including temporary solutions such as the application of corneal glue and bandage contact lens, as well as definitive treatment such as corneal transplantation. Tissue glues/adhesives were developed as substitutes for sutures in ophthalmic surgery. Unlike sutures, these glues are associated with shorter overall surgical times and reduced inflammation, thus improving postoperative comfort without compromising wound strength. The available tissue adhesives can be broadly classified into two types: synthetic (eg, cyanoacrylate derivatives) and biological (eg, fibrin glue). Cyanoacrylate glue is chiefly used as a corneal patch to manage acute corneal perforations and improve visual outcomes. Fibrin glue can be used instead of cyanoacrylate glue in many conditions with the benefits of reduced conjunctival and corneal inflammation and reaction. Apart from this, each type of adhesive is distinct in terms of its benefits as well as limitations and is accordingly used for different indications. The present review focuses on the two main types of tissue adhesives, their applications in the management of corneal perforations, the associated complications, safety and efficacy data related to their use available in the literature and the need for newer adhesives in this field.

Association of keratoconus with serum levels of 25-hydroxyvitamin D and antioxidant trace elements: A systematic review and meta-analysis.

The aim of this systematic review and meta-analysis was to summarize and compare the available evidence on the level of vitamin D and antioxidant trace elements between the keratoconus (KC) patients and healthy controls. Seven case-control studies with 830 subjects were found eligible with a systematic search using PubMed, SCOPUS, Web of Science, and EMBASE till November 21, 2021. Data were synthesized with a DerSimonian and Laird random-effects method of meta-analysis. The mean serum vitamin D level was significantly lower in the patients with KC [standardized mean difference (SMD): -0.71; P < 0.001] as compared with the control group. The mean serum vitamin D level decreased more in the progressive patients (SMD: -0.80; P = 0.016) than in the stable patients (SMD: -0.66; P < 0.001) when compared with the control group. The mean serum zinc level was found significantly lower in the patients with KC compared with the control group (SMD: -1.98; P = 0.005). Pooled analysis based on the two studies showed significantly lower mean selenium levels in the KC patients (SMD: -0.34; P = 0.003). Regular evaluation of serum vitamin D, zinc, and selenium levels among the patients with KC at disease onset and future follow-ups could be promising in predicting the progressive disease and disease severity.

Atomised intranasal dexmedetomidine versus oral melatonin in prevention of emergence delirium in children undergoing ophthalmic surgery with sevoflurane: A randomised double-blind study.

BACKGROUND: Melatonin and dexmedetomidine have both been used as a premedication to decrease emergence delirium in children. The effectiveness of oral melatonin, compared with atomised intranasal dexmedetomidine, in this role is not well studied. OBJECTIVE: To study the efficacy of pre-operative atomised intranasal dexmedetomidine versus oral melatonin in children scheduled for ophthalmic surgery under sevoflurane. DESIGN: A prospective, randomised, double-blind trial. SETTING: Ophthalmic surgery in a university teaching hospital, April 2021 to October 2021. PATIENTS: A total of 120 children undergoing ophthalmic surgery with sevoflurane anaesthesia. INTERVENTION: Children were randomised to receive pre-operative intranasal dexmedetomidine 2 µg/kg via an atomiser device (dexmedetomidine group) or oral melatonin 0.5 mg kg -1 (melatonin group), 45 min before surgery. OUTCOMES MEASURED: The primary outcome was the incidence of emergence delirium assessed by the Paediatric Anaesthesia Emergence Delirium scale. Secondary outcomes included pre-operative sedation, quality of inhalational induction, postoperative sedation and pain. RESULTS: The incidence of emergence delirium was lower in the dexmedetomidine group than in the melatonin group (17 versus 37%, relative risk 0.45, 95% CI: 0.24 to 0.88; P  = 0.01). Children in the dexmedetomidine group were more sedated following premedication and in the postanaesthesia care unit ( P  < 0.05). Postoperative pain scores were lower in the dexmedetomidine group than in the melatonin group: 0 [0 to 3] versus 2.5 [0-4], ( P  = 0.01). The requirement for and dose of rescue fentanyl analgesia postoperatively was comparable between the two groups. CONCLUSION: Atomised intranasal dexmedetomidine significantly reduced emergence delirium in paediatric opthalmic procedures under sevoflurane anaesthesia compared to oral melatonin. TRIAL REGISTRATION: Clinical Trials Registry of India CTRI/2021/03/032388 ( www.ctri.nic.in ).

Coping Strategy, Life Style and Health Status During Phase 3 of Indian National Lockdown for COVID-19 Pandemic-A Pan-India Survey.

The implementation of timely COVID-19 pan-India lockdown posed challenges to the lifestyle. We looked at the impact of lifestyle on health status during the lockdown in India. A self-rated scale, COVID Health Assessment Scale (CHAS) was circulated to evaluate the physical health or endurance, mental health i.e. anxiety and stress, and coping ability of the individuals under lockdown. This is a pan-India cross-sectional survey study. CHAS was designed by 11 experts in 3 Delphi rounds (CVR = 0.85) and was circulated through various social media platforms, from 9th May to 31st May 2020, across India by snowball circulation method. CHAS forms of 23,760 respondents were downloaded from the Google forms. Logistic regression using R software was used to compare vulnerable (>60 years and with chronic diseases) with non-vulnerable groups. There were 23,317 viable respondents. Majority of respondents included males (58·8%). Graduates/Postgraduates (72·5%), employed (33·0%), businessmen (6·0%), and professionals (9·7%). The vulnerable group had significantly (OR 1.31, p < 0.001) higher representation of overweight individuals as compared to non-vulnerable group. Regular use of tobacco (OR 1.62, p = 0.006) and other addictive substances (OR 1.80, p = 0.039) showed increased vulnerability. Respondents who consume junk food (OR 2.19, p < 0.001) and frequently snack (OR 1.16, p < 0.001) were more likely to be vulnerable. Respondents involved in fitness training (OR 0.57, p < 0.001) or did physical works other than exercise, yoga, walk or household activity (OR 0.88, p = 0.004) before lockdown were less likely to be vulnerable. Majority had a very good lifestyle, 94.4% never smoked or used tobacco, 92.1% were non-alcoholic, 97.5% never used addictive substances, 84.7% had good eating habits, 75.4% were vegetarians, 82.8% had "good" sleep, 71.7% did physical activities. Only 24.7% reported "poor" coping ability. Depression with somewhat low feeling were more likely to be vulnerable (OR 1.26, p < 0.001). A healthy lifestyle that includes healthy eating, proper sleep, physical activeness and non-addictive habits supports better coping ability with lesser psychological distress among Indian population during lockdown.

Axial myopia, a protective factor for diabetic retinopathy-role of vascular endothelial growth factor.

Long axial length is one of the ocular protective factors in development of diabetic retinopathy (DR). In this study we examined the effect of axial length (AL) on aqueous humor vascular endothelial growth factor (VEGF) levels in patients with diabetes mellitus with or without DR. Forty-eight eyes of 48 participants were divided into three groups of 16 each. Group A consisted of non-diabetic patients, Group B had diabetic patients without DR, and Group C had diabetic patients with treatment-naive non-proliferative DR (NPDR). The groups were further subdivided based on axial lengths i.e., AL ≤ 23.30 mm (A1, B1, C1) and AL > 23.30 mm (A2, B2, C2). Undiluted aqueous humor was obtained during cataract surgery to measure the VEGF levels. We observed significant decrease in VEGF concentration in patients with AL ≥ 23.30 mm as compared with AL ≤ 23.30 mm in non-diabetic as well as diabetic patients. As the eye elongates, there is less secretion of VEGF in non-diabetics as well in diabetics with or without DR. Our findings strengthened the concept that an increase in AL leads to less VEGF in diabetic eyes, thus leading to less severe DR changes.

Corneal and corneal epithelial thickness distribution characteristics in healthy North Indian eyes using spectral domain optical coherence tomography.

Purpose: To determine the pattern of corneal thickness and epithelial thickness distribution in healthy North Indian eyes by using spectral domain optical coherence tomography (SD-OCT). Methods: The observational study measured total corneal and epithelial thickness in the central 2 mm zone and eight sectors each in paracentral 2-5 mm (ring 1) and midperipheral 5-7 mm (ring 2) zones on SD-OCT. Results: The study included 67 eyes of 67 subjects with a male:female ratio of 32:35 and mean age of 25.04 ± 4.54 years. The mean central corneal and epithelial thicknesses were 505.97 ± 30.12 µm and 60.48 ± 8.37 µm, respectively. The epithelium of inferior and infero-nasal sectors in ring 1 and inferior sector in ring 2 was significantly thicker than the radially opposite sectors of the respective rings (P = 0.001; P = 0.01 and P = 0.02, respectively). Sector-wise analysis did not reveal any significant correlation between the total corneal thickness and epithelial thickness (all P > 0.05) except in the outer superior sector where there was a weak positive correlation (r = 0.28, P = 0.02). Central epithelial thickness in males (60.59 ± 9.28 µm) and females (60.37 ± 7.58 µm) was comparable (P = 0.91). Pachymetry was thinnest in the inferior, inferonasal, and inferotemporal sectors in 44.79% of eyes (n = 30), while thinnest epithelium was seen in the superior, superonasal, and superotemporal quadrants in 50.75% of eyes (n = 34). Conclusion: The epithelial thickness distribution in this sample of topographically normal healthy North Indian eyes was nonuniform and independent of the underlying corneal thickness. Epithelium was thinner in the superior cornea, whereas total corneal thickness was minimum in the inferior part.

Association of screen time, quality of sleep and dry eye in college-going women of Northern India.

PURPOSE: To evaluate the association of daily screen time and quality of sleep with the prevalence of dry eye among college-going women. METHODS: This study was a cross-sectional, comparative questionnaire-based study of 547 college-going women in northern India. A 10-item Mini Sleep Questionnaire was used to check the quality of sleep, and the Standard Patient Evaluation of Eye Dryness (SPEED) scale was used to examine the prevalence of dry eye among college-going women. RESULTS: Multinomial logistic regression showed a significant association between dry eye with daily screen time spent (P < 0.05) and the quality of sleep (P < 0.05) among college-going girls. Using Latent Class Analysis, two latent classes were selected based on the Bayesian Information Criteria. It was found that the majority population falls in class two and was having Severe Sleep-Wake difficulty. It was seen that the participants in class two belonged to the age bracket of 18-21 years, were from stream Humanities, education of father and mother equal to graduation, father working only, belonging to the nuclear family, having one sibling, hailing from the urban locality, spending more than 6 h daily on-screen, a majority of them using mobile phones, not using eye lubricants, and reported an increase in screen time during COVID-19. CONCLUSION: Dry eye and sleep quality are essential global health issues, and coupled with increased screen time, may pose a challenge in the present era. Preventive strategies need to be incorporated in school and college curriculums to promote physical, social, and psychological well-being and quality of life.

Efficacy of 2% Rebamipide Suspension for Vernal Keratoconjunctivitis: A Clinical Comparison with Topical Immune Modulators Cyclosporine and Tacrolimus.

PURPOSE: To compare the efficacy of 2% rebamipide suspension with topical cyclosporine and tacrolimus for managing vernal keratoconjunctivitis (VKC). METHODS: In this prospective, interventional study, 38 patients with moderate to severe VKC were allocated to receive either 2% rebamipide in one eye and 0.03% tacrolimus ointment in the contralateral eye (n = 19) or 2% rebamipide in one eye and 0.05% cyclosporine in the contralateral eye (n = 19) for 12 weeks. Ten ocular signs and 7 symptoms were graded on a scale of 0-3 each for each eye at every visit. RESULTS: Total sign and symptom scores reduced significantly in all 4 subgroups (all p's <0.05) at 12 weeks. Reduction of mean sign scores between rebamipide and tacrolimus (- 4.67 ± 4.63 and - 2.80 ± 3.18 respectively) and between rebamipide and cyclosporine (-6.00 ± 3.74 and -5.42 ± 3.68 respectively) was comparable. Reduction in symptom scores was also comparable between subgroups. CONCLUSION: Our findings suggest that efficacy of topical rebamipide is comparable to topical cyclosporine and tacrolimus for managing moderate to severe VKC and it merits further evaluation as a novel steroid sparing alternative for this disorder.

Intraocular lens power calculation formula in congenital cataracts: Are we using the correct formula for pediatric eyes?

The major challenge these days in pediatric cataract surgery is not the technique of surgery or intraocular lens (IOL) used but the postoperative refractive error. Amblyopia occurring due to postoperative refractive error which the child has; destroys the benefit obtained by a near-perfect and timely surgery. Even if we settle the debate as to what should be the ideal postoperative target refraction, there is a postoperative surprise that is not explained by our conventional insights of an accurate power calculation in children. The role of IOL power calculation formulae in affecting the postoperative refractive error should not be underestimated. Therefore, which age-appropriate formula is to be used for children is unclear. This review is an update on major IOL power calculation formulas used in pediatric eyes. We have tried to define why we should not be using these formulas made for adult eyes and review the literature in this regard.