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ABSTRACT: The Descemet membrane (DM) is the basement membrane of corneal endothelial cells, which are responsible for maintaining corneal transparency. DM detachment (DMD) can occur due to various reasons, with the most common etiology being post-surgical. Older age, blunt instruments, and faulty surgical technique predispose to the intraoperative or postoperative occurrence of DMD, and one should have a high index of suspicion for DMD in cases with unexplained or an atypical pattern of corneal edema after surgery. Prompt intervention for DMD management is imperative to effect early visual rehabilitation, decrease corneal morbidity, and avoid permanent damage leading to scarring of the cornea. Various classifications of DMD and management protocols have been described. Anterior-segment optical coherence tomography (AS-OCT) imaging is the most effective imaging to detect DMD and quantify its extent. Desmetopexy with air/gas is the initial treatment of choice and could be aided by suture fixation. Non-responsive cases might need endothelial keratoplasty.
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ABSTRACT: Corneal perforations are potentially sight-threatening conditions if not promptly treated. Management depends on the size, location, cause, and severity of the perforation. Various methods, including tissue adhesives, amniotic membrane grafting (AMG), and keratoplasty, are available. However, the limited availability of donor tissue in emergencies poses a significant challenge. Recently, Tenon's patch grafting (TPG) has emerged as a promising treatment option due to its autologous nature, availability, and lack of immunogenicity. This review provides a comprehensive overview of various aspects of TPG, along with relevant images. A literature search using keywords such as "Tenon's patch graft," "Tenon's capsule," "corneal patch graft," "amniotic membrane," and "corneal perforations" yielded 37 articles, included in this review. TPG is suitable for cases involving corneal tissue degradation leading to perforation, impending perforation, or descemetocele, with lesion sizes ranging from 2 to 6 mm. For larger perforations, the procedure may be modified by combining it with AMG or tissue adhesives. Postoperatively, the graft undergoes characteristic changes, including epithelialization and collagen deposition, resulting in the formation of a thick scar. Complications such as delayed epithelialization, wound leaks, and graft dehiscence can occur. High success rates have been reported, ranging from 74% to 87%. However, TPG may result in suboptimal visual outcomes, particularly when the graft is centrally located, necessitating future keratoplasty for visual rehabilitation. Overall, TPG is a safe and cost-effective technique for restoring structural integrity in corneal thinning disorders and perforations, especially in emergency settings when donor tissue is unavailable.
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Acute corneal hydrops (ACH) is a rare but sight-threatening complication of corneal ectasias. We aim to review the current literature on etiopathogenesis, histology, role of ancillary investigations, management, and outcomes of ACH by classifying the various management strategies based on their site of action and the underlying mechanism. A review of the literature was conducted by searching the following databases: PubMed (United States National Library of Medicine), Embase (Reed Elsevier Properties SA), Web of Science (Thomson Reuters), and Scopus (Elsevier BV) till April 2023. The literature search used various combinations of the following keywords: acute corneal hydrops, keratoconus, ectasia, management, keratoplasty. Nine hundred eighty-three articles were identified based on the above searches. Case reports which did not add any new modality of treatment to the existing literature, articles unrelated to management, those with no full text available, and foreign-language articles with no translation available were excluded. Eventually, 75 relevant articles that pertained to the management of ACH were shortlisted and reviewed. Recent studies have described newer surgical interventions like full-thickness or pre-Descemetic sutures, thermokeratoplasty, and plasma injection that aim to close the posterior stromal break. Posterior lamellar keratoplasties act by replacing the posterior torn Descemet's membrane (DM), and early deep anterior lamellar keratoplasty (DALK) has been attempted to combine the correction of the anatomical defect and visual rehabilitation in a single surgery. These surgical interventions may help by reducing the scarring and increasing the number of patients who can be visually rehabilitated with contact lenses rather than keratoplasty.
Subject(s)
Corneal Edema , Corneal Transplantation , Keratoconus , Humans , Corneal Edema/diagnosis , Corneal Edema/etiology , Corneal Edema/therapy , Corneal Transplantation/adverse effects , Cornea , Keratoconus/complications , Keratoconus/diagnosis , Keratoconus/surgery , EdemaABSTRACT
High-precision biometry and accurate intraocular lens (IOL) power calculation have become essential components of cataract surgery. In clinical practice, IOL power calculation involves measuring parameters such as corneal power and axial length and then applying a power calculation formula. The importance of posterior corneal curvature in determining the true power of the cornea is increasingly being recognized, and newer investigative modalities that can estimate both the anterior and posterior corneal power are becoming the standard of care. Optical biometry, especially using swept-source biometers, with an accuracy of 0.01-0.02 mm, has become the state-of-the-art method in biometry. With the evolution of IOL formulas, the ultimate goal of achieving a given target refraction has also moved closer to accuracy. However, despite these technological efforts to standardize and calibrate methods of IOL power calculation, achieving a mean absolute error of zero for every patient undergoing cataract surgery may not be possible. This is due to inherent consistent bias and systematic errors in the measurement devices, IOL formulas, and the individual bias of the surgeon. Optimization and personalization of lens constants allow for the incorporation of these systematic errors as well as individual bias, thereby further improving IOL power prediction accuracy. Our review provides a comprehensive overview of parameters for accurate biometry, along with considerations to enhance IOL power prediction accuracy through optimization and personalization. We conducted a detailed search in PubMed and Google Scholar by using a combination of MeSH terms and specific keywords such as "ocular biometry," "IOL power calculations," "prediction accuracy of refractive outcome in cataract surgery," "effective lens position," "intraocular lens calculation formulas," and "optimization of A-constants" to find relevant literature. We identified and analyzed 121 relevant articles, and their findings were included.
Subject(s)
Cataract , Lenses, Intraocular , Phacoemulsification , Humans , Lens Implantation, Intraocular/methods , Phacoemulsification/methods , Refraction, Ocular , Biometry/methods , Cornea/surgery , Retrospective Studies , Optics and PhotonicsABSTRACT
PURPOSE: To study the correlation of corneal topography, corneal biomechanical properties, and ocular aberrations with the magnitude of refractive error in myopic eyes. METHODS: All myopic patients attending the clinic for refractive surgery were recruited. Data recorded included visual acuity, axial length (AL), central corneal thickness (CCT), manifest refraction spherical equivalent (MRSE), topography (Pentacam - Oculus), corneal biomechanical factors [ocular response analyzer (ORA)], and optical aberrations (iTrace). They were further categorized into group 1 (suitable for femto-LASIK) and group 2 (unsuitable for femto-LASIK). RESULTS: Sixty eyes (30 myopes) of mean age 22.78 ± 2.71 years were enrolled. A negative correlation of refractive error was noted with AL (ρ = -0.9; P < 0.001), total aberrations (ρ = 0.53; P < 0.001), and lower-order aberrations (LOA) (ρ = 0.54; P < 0.001). A strongly positive correlation was noted between CCT and corneal hysteresis (CH) (ρ = 0.63; P < 0.001), CCT and CRF (ρ = 0.56; P < 0.001), CH and corneal resistance factor (CRF) (ρ = 0.83; P < 0.001), and Goldmann equivalent intraocular pressure (IOPg) and corneal compensated intraocular pressure (IOPcc) (ρ = 0.78; P < 0.001). An increase in higher-order aberrations (HOAs) as well as lower-order aberrations (LOAs) was noted with increasing sim-K [HOA (r = 0.73, P = 0.001); LOA (r = 0.601, P = 0.014)] and increasing CRF [HOA (r = 0.5, P = 0.006); LOA (r = 0.732, P = 0.001)] in group 2. The amount of refractive error, axial length, central corneal thickness, and sim-K were significantly different in the two groups. CONCLUSION: Increasing degree of myopia is associated with an increase in axial length, total aberrations, and lower-order aberrations. Corneal biomechanical parameters have a strong correlation with each other. Lower corneal biomechanics are noted in high myopes as they have weaker and thinner corneas. Corneal biomechanics and ocular aberrations do not differ significantly between cases suitable for femto-LASIK and cases unsuitable for femto-LASIK.
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Keratomileusis, Laser In Situ , Myopia , Refractive Errors , Humans , Young Adult , Adult , Cornea , Myopia/diagnosis , Myopia/surgery , Intraocular Pressure , Biomechanical PhenomenaABSTRACT
PURPOSE: The aim of this study was to evaluate the role of cutaneous application of 0.1% tacrolimus eye ointment over the skin of the upper eyelid in chronic vernal keratoconjunctivitis (VKC). METHODS: A prospective, longitudinal, noncomparative, open-label clinical study of moderate-to-severe grade steroid-dependent VKC was performed. Study participants were initiated on adjunct therapy of cutaneous application of 0.1% tacrolimus ointment twice daily on the upper eyelid skin. Ocular surface evaluation parameters, meibomian gland imaging, intraocular pressure, visual acuity, and clinical disease severity scoring were performed to assess clinical response at baseline and month 3 of therapy. Tear levels of tacrolimus were measured at month 3 using high-performance liquid chromatography tandem mass spectrometry and correlated with the clinical score. RESULTS: Palpebral form of VKC was observed in 85% of the cases, with positive family history in 5%, atopy in 7.5%, and keratoconus in 11.25%. Clinical assessment revealed improvement in 97.5% patients with discontinuation of concomitant topical steroids in 64% of patients. There were no changes in visual acuity, intraocular pressure, or ocular surface evaluation after therapy. Tacrolimus was detected in the tears of all our study patients after cutaneous application over the upper eyelid skin, proving its bioavailability with mean tear tacrolimus levels of 6.55 ± 21.43 ng/mL. Correlation analysis revealed a moderate negative correlation between the clinical score and tacrolimus concentration (Spearman correlation coefficient: -0.34, P = 0.002). CONCLUSIONS: Cutaneous tacrolimus 0.1% ointment over the upper eyelid skin is an efficacious alternative method of application in treatment of VKC, with no resultant ocular irritation.
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Eye Injuries , Humans , Eye Injuries/complications , Eye Injuries/diagnosis , Retrospective StudiesABSTRACT
Systemic coronavirus disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has had several ocular consequences. Many vaccines have been developed against the disease, with adverse events being reported as well. Various ocular adverse events secondary to coronavirus disease 2019 (COVID-19) vaccines have also featured in literature in recent times. This review features the reported corneal-related effects of COVID infection and vaccination. These include direct effects on corneal grafts and unilateral or bilateral corneal melts. The compilation of reported experiences from across the world in this systematic review will help clinicians recognize the possible presentations, pathogenesis, and management of the same.
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COVID-19 , Viral Vaccines , Humans , COVID-19 Vaccines/adverse effects , COVID-19/epidemiology , SARS-CoV-2 , MorbiditySubject(s)
Corneal Edema , Corneal Ulcer , Humans , Benzoates , Intraocular Pressure , Edema , Corneal Edema/chemically induced , Corneal Edema/diagnosisABSTRACT
Corneal blindness ranks third among the causes of blindness worldwide, after cataract and glaucoma. Corneal transplantation offers us a means to address this, and is currently the most commonly performed transplantation procedure worldwide - restoring the gift of sight to many an eye. Eye banks play a very important role in these procedures. India was quick to develop its own eye bank in 1945 soon after the launch of world's first eye bank in 1944. The evolution over the past six decades has been tremendous, placing India on the top, with one of the largest eye-banking system in the world. As of 2023, around 740 members are registered under the Eye Bank Association of India. The highest-ever collection of 71,700 donor eyes was achieved in 2017-2018. The overall tissue utilisation rate ranged between 22 - 28 % for voluntary donations and 50% for hospital-based corneal retrieval programs. Though India has an excellent infrastructure and readiness for corneal transplantation surgery, the need of the hour is to create a strong and independent nodal system. It shall take care of the logistics and factor in technological advances - surgical and otherwise. Public awareness, a national corneal grid, and reducing the red-tape barriers, shall improve availability of grafts nationwide. This review aims to detail the evolution of eye banking in India, to provide a comprehensive understanding, and help the stakeholders focus on the road ahead to attain our targets faster.
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Corneal Transplantation , Eye Banks , Humans , India/epidemiology , Cornea , BlindnessABSTRACT
Purpose: Barrett toric calculator (BTC) is known for its accuracy in toric IOL (tIOL) calculation over standard calculators; however, there is no study in literature to compare it with real-time intraoperative aberrometry (IA). The aim was to compare the accuracy of BTC and IA in predicting refractive outcomes in tIOL implantation. Methods: This was an institution-based prospective, observational study. Patients undergoing routine phacoemulsification with tIOL implantation were enrolled. Biometry was obtained from Lenstar-LS 900 and IOL power calculated using online BTC; however, IOL was implanted as per IA (Optiwave Refractive Analysis, ORA, Alcon) recommendation. Postoperative refractive astigmatism (RA) and spherical equivalent (SE) were recorded at one month, and respective prediction errors (PEs) were calculated using predicted refractive outcomes for both methods. The primary outcome measure was a comparison between mean PE with IA and BTC, and secondary outcome measures were uncorrected distance visual acuity (UCDVA), postoperative RA, and SE at one month. SPSS Version-21 was used; P < 0.05 considered significant. Results: Thirty eyes of 29 patients were included. Mean arithmetic and mean absolute PEs for RA were comparable between BTC (-0.70 ± 0.35D; 0.70 ± 0.34D) and IA (0.77 ± 0.32D; 0.80 ± 0.39D) (P = 0.09 and 0.09, respectively). Mean arithmetic PE for residual SE was significantly lower for BTC (-0.14 ± 0.32D) than IA (0.001 ± 0.33D) (-0.14 ± 0.32D; P = 0.002); however, there was no difference between respective mean absolute PEs (0.27 ± 0.21 D; 0.27 ± 0.18; P = 0.80). At one-month, mean UCDVA, RA, and SE were 0.09 ± 0.10D, -0.57 ± 0.26D, and -0.18 ± 0.27D, respectively. Conclusion: Both IA and BTC give reliable and comparable refractive results for tIOL implantation.
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Astigmatism , Lenses, Intraocular , Phacoemulsification , Humans , Aberrometry , Lens Implantation, Intraocular/methods , Prospective Studies , Refraction, Ocular , Cornea , Astigmatism/surgeryABSTRACT
Purpose: To evaluate the efficacy of liposomal amphotericin B (L-AMB) for the treatment of fungal keratitis. Methods: Patients with fungal keratitis confirmed by potassium hydroxide (KOH) smear and/or confocal microscopy were administered topical L-AMB and randomized into three groups treated with three different formulations. The medication was administered two hourly till clinical improvement was achieved, followed by six hourly till complete resolution. The outcome measures were time to clinical improvement, resolution of epithelial defect, stromal infiltrate, hypopyon, extent and density of corneal opacity, neovascularization, and best corrected visual acuity (BCVA) at 3 months. Results: Mean age of the patients was 46.6 ± 14.8 years, and trauma with vegetative matter was the most common predisposing factor. Aspergillus flavus (36%) was the most common fungus cultured, followed by Fusarium (23%). Mean time to clinical improvement, time to resolution of epithelial defect, mean time to resolution of infiltrate, and time to resolution of hypopyon were 3.45 ± 1.38, 25.35 ± 8.46, 37.97 ± 9.94, and 13.33 ± 4.90 days, respectively, and they were comparable among the three groups. There was a significant difference between treatment failure and success cases in terms of days of presentation (P < 0.01), size of the epithelial defect (P-value 0.04), and infiltrate size at presentation (P-value 0.04). At 3 months follow-up, no statistically significant difference was noted in BCVA and mean scar size among groups. Conclusion: L-AMB in a gel form is an effective antifungal agent that promotes the healing of fungal ulcers with notably least vascularization and better tolerance. Trial registration number: CTRI/2020/04/024550.
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Corneal Ulcer , Eye Infections, Fungal , Humans , Adult , Middle Aged , Amphotericin B/therapeutic use , Corneal Ulcer/microbiology , Antifungal Agents/therapeutic use , Eye Infections, Fungal/diagnosis , Eye Infections, Fungal/drug therapy , Eye Infections, Fungal/microbiology , HospitalsABSTRACT
Mucopolysaccharidosis are group of inherited metabolic diseases caused by the absence or malfunctioning of lysosomal enzymes resulting in accumulation of glycosaminoglycans. Over time this accumulation damages cells, tissues, and organs. There are seven types of MPS and 13 subtypes that are associated with multiple organ systems, such as the respiratory, liver, spleen, central nervous systems, arteries, skeletons, eyes, joints, ears, skin, and/or teeth. The various types share some common ocular features that differ in terms of the severity of the affection. Visual loss in MPS patients is varied and can be due to corneal clouding, glaucoma, retinopathy, and optic neuropathy. The primary focus of this review is on changes in the cornea and anterior segment in MPS patients, including clinical and novel investigative modalities, current surgical management, effects of systemic therapy like hematopoietic stem cell transplants (HSCT)and enzyme replacement therapy (ERT), as well as significant research developments.
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Purpose: To study the antifungal susceptibility of common corneal pathogenic fungi to antifungal agents in the North Indian population. Methods: Prospective study of the antifungal sensitivity testing (natamycin, amphotericin B, voriconazole, itraconazole, fluconazole, posaconazole, caspofungin, micafungin) of fungal isolates from 50 cases of culture positive fungal keratitis by using E test method. Details noted included demographic data, visual acuity, clinical details, grade of keratitis, healing time, and success in medical management. Results: Of 50 patients with fungal keratitis (mean age: 40.28 ± 16.77 years), 12 eyes healed within 3 weeks, 14 had a delayed healing response, and 24 had chronic keratitis. Among the 15 cases of Fusarium isolates, 93.3% were sensitive to natamycin, while 40% to amphotericin B; 66.6% to voriconazole, 13.4% to itraconazole and fluconazole each. 80% of Fusarium cases (n = 12) showed susceptibility to posaconazole. Among Aspergillus flavus isolates, 53.4% (n = 8) were sensitive to natamycin, with only 40% (n = 7) showing sensitivity to amphotericin B and good susceptibility to azoles. MIC against susceptible Fusarium spp. for natamycin was 3-16 µg/mL, amphotericin B: 1-8 µg/mL, voriconazole: 0.5-1.5 µg/mL, itraconazole: 0.5-12 µg/mL, posaconazole: 0.094-1.5 µg/mL. MIC against Aspergillus flavus was natamycin: 8-32 µg/mL, amphotericin B: 0.5-16 µg/mL, voriconazole: 0.025-4 µg/mL, itraconazole: 0.125-8 µg/mL, posaconazole: 0.047-0.25 µg/mL; against Aspergillus niger isolates, to natamycin was 6 µg/mL (n=1), amphotericin B 8-12 µg/mL (n = 3), voriconazole: 0.125-0.19 µg/mL (n = 3), itraconazole: 0.38-0.75 µg/mL, posaconazole: 0.064-0.19 µg/mL and against Aspergillus fumigatus (n = 1), was natamycin4 µg/mL, amphotericin B - 8 µg/mL, voriconazole 0.25 µg/mL, itraconazole 1 µg/mL, and posaconazole 0.19 µg/mL. MIC against susceptible Acremonium spp. for natamycin was 1.5-16 µg/mL, amphotericin B: 0.5-8 µg/mL, voriconazole: 0.19-3 µg/mL, itraconazole: 0.125 µg/mL, posaconazole: 0.125-0.5 µg/mL and against susceptible Curvularia was natamycin 0.75-4 µg/mL, amphotericin B 0.5-1 µg/mL, voriconazole 0.125-0.19 µg/mL, itraconazole 0.047-0.094 µg/mL, posaconazole 0.047-0.094 µg/mL. MIC against Mucor spp.+ Rhizopus spp. (n = 1) was natamycin: 8 µg/mL, amphotericin B: 0.75 µg/mL, posaconazole: 1.5 µg/mL. MIC against of Alternaria (n = 1) was voriconazole: 0.19 µg/mL, posaconazole: 0.094 µg/mL. MIC against Penicillium (n=1) was natamycin: 8 µg/mL, voriconazole: 0.25 µg/mL, itraconazole: 0.5 µg/mL, and Posaconazole: 0.125 µg/mL. Conclusion: Our observations highlight the variations in susceptibility to antifungal agents. Posaconazole seems to be effective with low MIC against common corneal pathogenic fungal isolates.
Subject(s)
Corneal Ulcer , Eye Infections, Fungal , Humans , Young Adult , Adult , Middle Aged , Antifungal Agents/pharmacology , Voriconazole/pharmacology , Natamycin/pharmacology , Amphotericin B/pharmacology , Itraconazole/pharmacology , Tertiary Care Centers , Fluconazole , Prospective Studies , Eye Infections, Fungal/drug therapy , Eye Infections, Fungal/epidemiologyABSTRACT
PURPOSE: To compare the ocular surface parameters of children with vernal keratoconjunctivitis (VKC) with those of healthy controls and to correlate cytological characteristics with clinical findings and disease severity. METHODS: Newly diagnosed cases of VKC, not currently being treated, were recruited, along with age-matched controls with no ocular comorbidities. The Ocular Surface Disease Index questionnaire (OSDI) was administered to all children. Slit lamp biomicroscopy for meibomian gland dysfunction and ocular surface analysis was performed, including tear meniscus height, noninvasive tear film break-up time, lipid layer thickness, meibomian gland morphology, and meibomian gland duct distortion on meibography imaging. Conjunctival impression cytology was also performed. RESULTS: A total of 68 VKC patients and 33 controls were included. Statistically significant difference was seen in the mean OSDI score (30 ± 13.7 vs 16.1 ± 3 [P ≤ 0.01]), lipid layer thickness (24.2 ± 7.9 nm vs 69.9 ± 15.1 nm [P <0.001]), and noninvasive tear film break-up time (6.8 ± 1.7 vs 12.5 ± 1.8 sec [P < 0.01]) between groups. Mean tear meniscus height was 0.22 ± 0.06 mm in the VKC and 0.24 ± 0.04 mm in the control group (P = 0.096). Significant association was seen between grade of squamous metaplasia and severity of VKC (P < 0.01). Severity of VKC was found to be positively correlated with OSDI score (r = 0.767), grade of squamous metaplasia (r = 0.64) and negatively correlated with noninvasive tear film break-up time (r = -0.468), and lipid layer thickness (r = -0.253). CONCLUSIONS: This study highlights the poor ocular surface health of children with VKC, with severe disease being associated with worse forms of dry eye disease.