Techniques of noncircular corneal transplantation.

PURPOSE OF REVIEW: The management of peripheral corneal diseases, including Mooren's ulcer, Terrien's marginal degeneration, peripheral ulcerative keratitis and pellucid marginal degeneration is challenging. Circular grafts must either be very large, resulting in the excision of healthy tissue, or eccentric, leading to high levels of astigmatism. This review summarizes the range of noncircular keratoplasty procedures available to surgeons, in addition to their indications, and surgical techniques. RECENT FINDINGS: Noncircular grafts have been demonstrated to be useful in the management of peripheral corneal diseases. They are effective at providing tectonic support and also facilitate visual rehabilitation. Specifically, they produce favourable postoperative visual and astigmatic outcomes. The evidence relating to these procedures is largely limited to case reports and case series, with no large-scale studies available. SUMMARY: Noncircular keratoplasty procedures are useful in the management of peripheral corneal diseases, which is typically difficult. There is a need for larger studies to investigate the relative advantages and disadvantages of these procedures and further characterize their outcomes.

Central Toxic Keratopathy After Collagen Cross-Linking: A Case Series.

PURPOSE: The aim of this study was to report a case series of central toxic keratopathy (CTK) after collagen cross-linking (CXL) in keratoconus. METHODS: This is a retrospective case series between January 2020 and September 2021. In this period, CXL was performed for progressive keratoconus in 964 eyes. CXL was performed using the epithelium-off accelerated protocol in all patients with a riboflavin soak time of 20 minutes and a UVA light exposure of 9 mW for 10 minutes using the Avedro KXL (Glaukos Inc, Aliso Viejo, CA) cross-linking system. RESULTS: Twelve of 964 eyes (1.2%) developed CTK within 1 week of CXL. All patients presented with well-circumscribed, central disciform haze that was broader in the anterior stroma and narrower in the posterior stroma. We noted initial flattening in keratometry up to 3 months post-CXL in these patients, which gradually steepened over 12 months, but did not reach preoperative levels. We also noted exuberant flattening in pachymetry in the first 3 months, which improved over 12 months. There was a statistically significant decrease in pachymetry in patients who developed CTK at 3 and 12 months postoperatively when compared to patients who underwent CXL but did not develop CTK. CONCLUSIONS: Several reports of CTK postrefractive surgery have been described previously. However, the association of CXL in the development of CTK has not been described previously. Here, we elucidated the clinical features of CTK after CXL and how it differs from corneal scarring or haze that occurs post-CXL.

Keratoconus in India: Clinical presentation and demographic distribution based on big data analytics.

PURPOSE: This paper aims to describe the clinical presentation and demographic distribution of keratoconus (KCN) in India by analyzing the electronic medical records (EMR) of patients presenting at a multitier ophthalmology hospital network. METHODS: This cross-sectional hospital-based study included the data of 2,384,523 patients presenting between January 2012 and March 2020. Data were collected from an EMR system. Patients with a clinical diagnosis of KCN in at least one eye were included in this study. Univariate analysis was performed to identify the prevalence of KCN. A multiple logistic regression analysis was performed using R software (version 3.5.1), and the odds ratios are reported. RESULTS: Data were obtained for 14,749 (0.62%) patients with 27,703 eyes diagnosed with KCN and used for the analysis. The median age of the patients was 22 (inter-quartile range (IQR): 17-27). In total, 76.64% of adults (odds ratio = 8.77; P = <0.001) were affected the most. The majority of patients were male (61.25%), and bilateral (87.83%) affliction was the most common presentation. A significant proportion of the patients were students (63.98%). Most eyes had mild or no visual impairment (<20/70; 61.42%). Corneal signs included ectasia (41.35%), Fleischer ring (44.52%), prominent corneal nerves (45.75%), corneal scarring (13.60%), Vogts striae (18.97%), and hydrops (0.71%). Only 7.85% showed an association with allergic conjunctivitis. A contact lens clinic assessment was administered to 47.87% of patients. Overall, 10.23% of the eyes affected with KCN underwent a surgical procedure. the most common surgery was collagen cross-linking (8.05%), followed by deep anterior lamellar keratoplasty (1.13%) and penetrating keratoplasty (0.88%). CONCLUSION: KCN is usually bilateral and predominantly affects males. It commonly presents in the second and third decade of life, and only a tenth of the affected eyes require surgical treatment.

Prevailing practice patterns in keratoconus among Indian ophthalmologists.

Objective: The past few years have seen a rapid advancement in the management of keratoconus (KC). However, there is no prescribed standard of care for the management of KC. This study evaluated the prevailing practice patterns among Indian ophthalmologists in the diagnosis and treatment of KC via an online survey. Methods: This was a survey-based cross-sectional study in which a questionnaire (Supplement 1) was created. Questions pertaining to the practicing experience, setting of practice, and training background were asked in addition to the investigations done and decision making in KC management. Responses were collected via Survey Monkey (Survey Monkey, Palo Alto, California, USA) and statistical analysis performed using R software (4.1.3). Results: The survey was answered by 273 ophthalmologists. Pentacam was the most used topographer (195 users), followed by Orbscan (41 users), Sirius (34 users), and Galilei (3 users). The lowest limit of pachymetry for performing collagen crosslinking (CXL) was 400µ for most practitioners. More than half the respondents (50.55%) did not perform photorefractive keratectomy (PRK) or intracorneal ring segment (ICRS) implantation in a suitable patient. Accelerated 10-minute protocol (9 mW/cm2 for 10 minutes) was the most commonly (54.21%) used for CXL, followed by Dresden protocol (3 mW/cm2 for 30 minutes) (36.63%). When a patient was unsuitable for CXL, 55.31% surgeons advise contact lens (CL) trial, 35.16% surgeons advise keratoplasty, 26.74% surgeons perform stromal augmentation, and 7.69% surgeons advise spectacle correction. Corneal scar was the most common indication (49.45%) for performing keratoplasty. Conclusion: Topography remains the most used diagnostic modality for initial diagnosis. Optical coherence tomography and epithelial mapping are increasingly being used for early diagnosis of KC. Not all ophthalmologists were comfortable performing ICRS or PRK. When patients are unsuitable for CXL, CL trial remains the most frequently advised option followed by keratoplasty.

Graft rejection in component keratoplasty.

Among the various indications for keratoplasty, failed graft is one of the commonest indications in many published series. It is well known that the major cause of graft failure is endothelial rejection. In the last two decades, there has been a major paradigm shift in the surgical management of corneal diseases, and component keratoplasty has emerged from the concept of replacing the layer that is actually diseased, rather than replacing the full-thickness cornea with the traditional penetrating keratoplasty. This has resulted in improved outcomes and the risk of endothelial rejection has reduced drastically, thus expanding the survival time of the graft. In recent years, reports of graft rejection in component keratoplasty have emerged, with each having a different presentation and responding to a different line of treatment. This review aims to summarize the presentation, diagnosis, and management of graft rejections in component keratoplasty.

Big data in corneal diseases and cataract: Current applications and future directions.

The accelerated growth in electronic health records (EHR), Internet-of-Things, mHealth, telemedicine, and artificial intelligence (AI) in the recent years have significantly fuelled the interest and development in big data research. Big data refer to complex datasets that are characterized by the attributes of "5 Vs"-variety, volume, velocity, veracity, and value. Big data analytics research has so far benefitted many fields of medicine, including ophthalmology. The availability of these big data not only allow for comprehensive and timely examinations of the epidemiology, trends, characteristics, outcomes, and prognostic factors of many diseases, but also enable the development of highly accurate AI algorithms in diagnosing a wide range of medical diseases as well as discovering new patterns or associations of diseases that are previously unknown to clinicians and researchers. Within the field of ophthalmology, there is a rapidly expanding pool of large clinical registries, epidemiological studies, omics studies, and biobanks through which big data can be accessed. National corneal transplant registries, genome-wide association studies, national cataract databases, and large ophthalmology-related EHR-based registries (e.g., AAO IRIS Registry) are some of the key resources. In this review, we aim to provide a succinct overview of the availability and clinical applicability of big data in ophthalmology, particularly from the perspective of corneal diseases and cataract, the synergistic potential of big data, AI technologies, internet of things, mHealth, and wearable smart devices, and the potential barriers for realizing the clinical and research potential of big data in this field.

Management of cataract in dry eye disease: Preferred practice pattern guidelines.

Cataract surgery is one of the most commonly performed ophthalmic surgeries in the world. Dry eye disease (DED) is found to coexist in most patients with cataracts due to the overlapping age groups of both these conditions. Preoperative evaluation for DED is important to improve outcomes. A pre-existing DED affecting the tear film is likely to affect biometry. Moreover, special intraoperative considerations are needed in eyes with DED to reduce complications and improve postoperative outcomes. Dry eye disease (DED) is known to occur following an uneventful cataract surgery or a pre-existing DED is likely to worsen following cataract surgery as well. In these situations, despite a good visual outcome, patient dissatisfaction is common owing to the distressing DED symptoms. This review aims to summarize the preoperative, intraoperative, and postoperative considerations when performing cataract surgery in the presence of a coexisting DED.

Management of corneal perforations in dry eye disease: Preferred practice pattern guidelines.

Corneal perforations in eyes with dry eye disease (DED) are difficult to manage due to the interplay of several factors such as the unstable tear film, surface inflammation, and the underlying systemic disease affecting the wound healing process, and the eventual outcome. A careful preoperative examination is required to identify the underlying pathology, and status of ocular surface and adnexa, rule out microbial keratitis, and order appropriate systemic workup in addition to assessing the perforation itself. Several surgical options are available, which include tissue adhesives, multilayered amniotic membrane grafting (AMT), tenon patch graft (TPG), corneal patch graft (CPG), and penetrating keratoplasty (PK). The choice of procedure depends upon the size, location, and configuration of the perforation. In eyes with smaller perforations, tissue adhesives are effective treatment modalities, whereas AMT, TPG, and CPG are viable options in moderate-sized perforations. AMT and TPG are also preferable in cases where the placement of a bandage contact lens may be a challenge. Large perforations require a PK, with additional procedures such as tarsorrhaphy to protect the eyes from the associated epithelial healing issues. Conjunctival flaps are considered in eyes with poor visual potential. The management of the acute condition is carried out in conjunction with measures to improve the tear volume bearing in mind the chances of delayed epithelialization and re-perforation in these cases. Administration of topical and systemic immunosuppression, when indicated, helps improve the outcome. This review aims to facilitate clinicians in instituting a synchronized multifaceted therapy for the successful management of corneal perforations in the setting of DED.

Management of keratoconus: an updated review.

Keratoconus is the most common corneal ectatic disorder. It is characterized by progressive corneal thinning with resultant irregular astigmatism and myopia. Its prevalence has been estimated at 1:375 to 1:2,000 people globally, with a considerably higher rate in the younger populations. Over the past two decades, there was a paradigm shift in the management of keratoconus. The treatment has expanded significantly from conservative management (e.g., spectacles and contact lenses wear) and penetrating keratoplasty to many other therapeutic and refractive modalities, including corneal cross-linking (with various protocols/techniques), combined CXL-keratorefractive surgeries, intracorneal ring segments, anterior lamellar keratoplasty, and more recently, Bowman's layer transplantation, stromal keratophakia, and stromal regeneration. Several recent large genome-wide association studies (GWAS) have identified important genetic mutations relevant to keratoconus, facilitating the development of potential gene therapy targeting keratoconus and halting the disease progression. In addition, attempts have been made to leverage the power of artificial intelligence-assisted algorithms in enabling earlier detection and progression prediction in keratoconus. In this review, we provide a comprehensive overview of the current and emerging treatment of keratoconus and propose a treatment algorithm for systematically guiding the management of this common clinical entity.

Graft detachments in endothelial keratoplasty.

Graft detachment is the most common complication of endothelial keratoplasty. With the ongoing advancements in the field of endothelial keratoplasty, our understanding of risk factors of graft detachments and its management has been evolving. Various prevention measures have been described in literature including presoaking the donor graft, anterior chamber tamponade, venting incisions, sutures to prevent dislocation of graft. Management of a detached graft involves secondary interventions such as rebubbling, suturing and regrafts. In this review, we discuss graft detachment in different types of endothelial keratoplasty techniques including Descemet stripping endothelial keratoplasty, Descemet stripping automated endothelial keratoplasty and Descemet's membrane endothelial keratoplasty; with emphasis on incidence, risk factors, preventive measures and their management.

Real-world experience of using ciclosporin-A 0.1% in the management of ocular surface inflammatory diseases.

PURPOSE: To report the real-world experience of using topical ciclosporin, Ikervis, in the management of ocular surface inflammatory diseases (OSIDs). METHODS: This was a retrospective study of patients treated with Ikervis for OSIDs at the Queen's Medical Centre, Nottingham, between 2016 and 2019. Relevant data, including demographics, indications, clinical parameters, outcomes and adverse events, were collected and analysed for patients who had completed at least 6 months follow-up. For analytic purpose, clinical outcome was categorised as 'successful' (resolved or stable disease), 'active disease' and 'drug intolerance'. RESULTS: 463 patients were included; mean age was 51.1±21.6 years, with a 59.0% female predominance. Mean follow-up was 14.6±9.2 months. The most common diagnosis was dry eye disease (DED; 322, 69.5%), followed by allergic eye disease (AED; 53, 11.4%) and ocular mucous membrane pemphigoid/Steven-Johnson syndrome (OMMP/SJS; 38, 8.2%). Successful treatment was achieved in 343 (74.1%) patients, with 44 (9.5%) requiring additional treatment and 76 (16.4%) reporting drug intolerance. The efficacy of Ikervis was highest in DED (264, 82.0%), followed by OMMP/SJS (25, 65.8%) and post-keratoplasty (7, 50.0%; p<0.001). Logistic regression analysis demonstrated age <70 years (p=0.007), AED (p=0.002) and OMMP/SJS (p=0.001) as significant predictive factors for Ikervis intolerance. AED and post-keratoplasty were 8.16 times (95% CI, 2.78 to 23.99) and 13.98 times (95% CI, 4.22 to 46.28), respectively, more likely to require additional treatment compared with DED. CONCLUSIONS: Ikervis is a useful steroid-sparing topical treatment for managing OSIDs in the real-world setting. Preparations with improved tolerability are needed to benefit a larger number of patients.

Success Rate of Growth Factors for Existing Periapical Lesions in Failed Endodontically Treated Teeth in Adult Population: A Systematic Review and Meta-Analysis.

Introduction: In this study, we investigated the success rate of growth factors for existing periapical lesions in failed endodontically treated teeth in an adult population by systematic review and meta-analysis. Materials and Methods: We conducted an online data search based on preferred reporting items for systematic reviews and meta analyses (PRISMA), from databases PUBMED, MEDLINE, and EMBASE, for the application of various types of growth factors in endodontically failed teeth with periapical lesions in adults. These included the "platelet-rich plasma (PRP) and platelet-rich fibrin (PRF)," blood, etc. The data were meta-analyzed using MetaXL 5.3, and GRADE was used to assess the certainty. Results: We observed that success of 0.95 was achieved by the end of a year's follow-up with the application of growth factors for periodontal lesions. We also observed that the teeth responded to thermal tests, indicating regeneration; however, studies were with bias and lower sensitivity. Discussion: \ Similar to regeneration in immature teeth, growth factors also showed greater success in the treatment of periapical lesions in the failed endodontic teeth in adults.

Diagnostic armamentarium of infectious keratitis: A comprehensive review.

Infectious keratitis (IK) represents the leading cause of corneal blindness worldwide, particularly in developing countries. A good outcome of IK is contingent upon timely and accurate diagnosis followed by appropriate interventions. Currently, IK is primarily diagnosed on clinical grounds supplemented by microbiological investigations such as microscopic examination with stains, and culture and sensitivity testing. Although this is the most widely accepted practice adopted in most regions, such an approach is challenged by several factors, including indistinguishable clinical features shared among different causative organisms, polymicrobial infection, long diagnostic turnaround time, and variably low culture positivity rate. In this review, we aim to provide a comprehensive overview of the current diagnostic armamentarium of IK, encompassing conventional microbiological investigations, molecular diagnostics (including polymerase chain reaction and mass spectrometry), and imaging modalities (including anterior segment optical coherence tomography and in vivo confocal microscopy). We also highlight the potential roles of emerging technologies such as next-generation sequencing, artificial intelligence-assisted platforms. and tele-medicine in shaping the future diagnostic landscape of IK.

Post-penetrating keratoplasty astigmatism.

Postoperative astigmatism is one of the common complications affecting visual outcomes after a penetrating keratoplasty. It can result from various factors related to host, donor and surgical technique, resulting in suboptimal visual outcome. While some of the measures taken during preoperative planning and during actual surgery can reduce the magnitude of postoperative astigmatism, postoperative correction of astigmatism is often required in cases with high degrees of astigmatism. When spectacles and contact lenses fail to provide optimal visual outcomes, various surgical techniques that include astigmatic keratotomy, compression sutures, toric intraocular lens placement, and laser refractive procedures can be considered. When none of these techniques are able to achieve a desired result with in the acceptable optical range, a repeat keratoplasty is considered a last option. We discuss the various causes and management of complication of postoperative astigmatism occurring after a full thickness corneal transplantation surgery.

Laser-assisted corneal transplantation surgery.

Corneal transplant surgeries have a broad range of indications with outcomes largely dependent on surgeon experience. Traditional manual techniques have certain limitations pertaining to the preparation of donor tissue and the recipient bed that might affect the predictability of visual outcomes. Use of lasers for keratoplasty procedures not only improves the repeatability and consistency of the technique, but also enables the surgeon to control the thickness and shape of the transplant tissue tailored to the specific condition. Despite the advantages, cost-effectiveness and technical know-how remain the major challenges. We discuss the various techniques of laser-assisted keratoplasties with respect to their methods, precision, and efficacy in various corneal indications.

Maternal finger-prick allogenic blood for persistent corneal epithelial defects.

This is a case of a 17-year-old patient with aniridia-related keratopathy and persistent epithelial defect (PED) treated successfully using maternal finger-prick blood (FPB). Maternal allogenic FPB treatment was initiated to the patient who was non-compliant with the use of autologous FPB. The PED was successfully managed with maternal FPB treatment with rapid and complete closure of the epithelial defect. Additionally, there was immediate and sustained symptomatic improvement to pain and recovery of vision in the only seeing eye. There was no immunological reaction to allogenic blood. Maternal finger-prick allogenic blood could serve as a potential alternative to serum eye drops or autologous FPB in the management of refractory PED, particularly in reference to the paediatric or the vulnerable age group. Further studies are required to confirm the role of allogenic blood in the treatment of PED.

Infectious keratitis: an update on epidemiology, causative microorganisms, risk factors, and antimicrobial resistance.

Corneal opacity is the 5th leading cause of blindness and visual impairment globally, affecting ~6 million of the world population. In addition, it is responsible for 1.5-2.0 million new cases of monocular blindness per year, highlighting an ongoing uncurbed burden on human health. Among all aetiologies such as infection, trauma, inflammation, degeneration and nutritional deficiency, infectious keratitis (IK) represents the leading cause of corneal blindness in both developed and developing countries, with an estimated incidence ranging from 2.5 to 799 per 100,000 population-year. IK can be caused by a wide range of microorganisms, including bacteria, fungi, virus, parasites and polymicrobial infection. Subject to the geographical and temporal variations, bacteria and fungi have been shown to be the most common causative microorganisms for corneal infection. Although viral and Acanthamoeba keratitis are less common, they represent important causes for corneal blindness in the developed countries. Contact lens wear, trauma, ocular surface diseases, lid diseases, and post-ocular surgery have been shown to be the major risk factors for IK. Broad-spectrum topical antimicrobial treatment is the current mainstay of treatment for IK, though its effectiveness is being challenged by the emergence of antimicrobial resistance, including multidrug resistance, in some parts of the world. In this review, we aim to provide an updated review on IK, encompassing the epidemiology, causative microorganisms, major risk factors and the impact of antimicrobial resistance.

Artificial Intelligence in Cornea, Refractive Surgery, and Cataract: Basic Principles, Clinical Applications, and Future Directions.

ABSTRACT: Corneal diseases, uncorrected refractive errors, and cataract represent the major causes of blindness globally. The number of refractive surgeries, either cornea- or lens-based, is also on the rise as the demand for perfect vision continues to increase. With the recent advancement and potential promises of artificial intelligence (AI) technologies demonstrated in the realm of ophthalmology, particularly retinal diseases and glaucoma, AI researchers and clinicians are now channeling their focus toward the less explored ophthalmic areas related to the anterior segment of the eye. Conditions that rely on anterior segment imaging modalities, including slit-lamp photography, anterior segment optical coherence tomography, corneal tomography, in vivo confocal microscopy and/or optical biometers, are the most commonly explored areas. These include infectious keratitis, keratoconus, corneal grafts, ocular surface pathologies, preoperative screening before refractive surgery, intraocular lens calculation, and automated refraction, among others. In this review, we aimed to provide a comprehensive update on the utilization of AI in anterior segment diseases, with particular emphasis on the recent advancement in the past few years. In addition, we demystify some of the basic principles and terminologies related to AI, particularly machine learning and deep learning, to help improve the understanding, research and clinical implementation of these AI technologies among the ophthalmologists and vision scientists. As we march toward the era of digital health, guidelines such as CONSORT-AI, SPIRIT-AI, and STARD-AI will play crucial roles in guiding and standardizing the conduct and reporting of AI-related trials, ultimately promoting their potential for clinical translation.

Topical use of alcohol in ophthalmology - Diagnostic and therapeutic indications.

Alcohol (ethanol) has been used in medicine since time immemorial. In ophthalmic practice, besides as an antiseptic, it was given as retrobulbar injections to relieve severe ocular pain. Alcohol can be applied topically to the surface of neoplastic or suspicious lesions to kill cells that might desquamate and seed during surgical excision, to treat epithelial ingrowth that can occur following corneal surgeries, particularly laser in situ keratomileusis (LASIK), and to treat superficial infectious keratitis. In view of its ability to achieve a smooth cleavage plane between the epithelium and the Bowman's layer, alcohol-assisted delamination (ALD) of the corneal epithelium has been used widely and effectively for a variety of diagnostic and therapeutic indications, at times delivering both outcomes. Diagnostically, ALD yields an intact epithelial sheet which can be fixed flat to provide excellent orientation for histopathological evaluation. Therapeutically, it is most commonly used to treat recurrent corneal erosion syndrome, where its efficacy is comparable to that of phototherapeutic keratectomy but with several advantages. It has also been used to treat various forms of epithelial/anterior stromal dystrophies, which can obviate or delay the need for corneal transplantation for several years. In addition, ALD is performed in corneal collagen cross-linking and corneal refractive surgery for relatively atraumatic removal of the epithelium. In this review, we aimed to provide a comprehensive overview of the diagnostic and therapeutic use of topical alcohol in ophthalmology, to describe the surgical and fixation techniques of ALD, and to highlight our experience in ALD over the past decade.