Background and Objective: Corneal neurotization is a novel surgical technique used to restore corneal sensation in patients with neurotrophic keratopathy. Neurotrophic keratopathy is a disorder characterized by dysfunction of the ophthalmic division of the trigeminal nerve, which provides sensory innervation to the cornea. Without sensation, the cornea is at risk of infection, ulceration, perforation, and ultimately, vision loss. Corneal neurotization has emerged as an innovative technique to reinnervate anesthetized corneas by transferring a healthy donor nerve to the affected eye around the corneoscleral limbus. As the field of corneal neurotization rapidly grows, there is a need to synthesize the existing body of literature on corneal neurotization and identify important areas for further research. In this review, we will discuss neurotrophic keratopathy and its current management strategies, followed by an overview of corneal neurotization techniques, outcomes, surgical considerations, and future directions. Methods: PubMed and Google Scholar searches were conducted to retrieve and analyze relevant original papers and reviews on neurotrophic keratopathy and corneal neurotization up until April 2022.Key Content and Findings: Currently, numerous techniques for corneal neurotization exist, including direct nerve transfers, as well as indirect neurotization via interposition nerve grafts. So far, corneal neurotization has been shown to be highly successful in restoring corneal sensation, improving visual acuity,and improving corneal epithelial health. To date, there have been no significant differences in outcomes between direct versus indirect neurotization techniques, different donor nerves, or autologous versus allogeneic interposition grafts. However, there is some evidence that corneal neurotization procedures may be more successful in pediatric patients.Conclusions: Corneal neurotization shows great promise in treating neurotrophic corneas and represents the first management option to date that addresses the underlying pathophysiological mechanism of neurotrophic keratopathy by restoring corneal sensation. As the use of corneal neurotization continues to broaden, additional studies will become important to compare techniques in a systematic manner, with larger sample sizes, as well as standardized outcome measures and follow-up time.

Background and Objective: Limbal stem cell deficiency (LSCD) is characterized by the insufficiency of limbal stem cells to maintain the corneal epithelium. Severe cases of LSCD may be treated with limbal transplantation from healthy autologous or allogeneic limbal tissue. Multiple cell-based therapies have been studied as alternative treatments to improve success rates and minimize immunosuppressive regimens after allogeneic transplants. In this review, we describe the success rates, and complications of different cell-based therapies for LSCD. We also discuss each therapy’s relative strengths and weaknesses, their history in animal and human studies, and their effectiveness compared to traditional transplants.

Methods: PubMed was searched for publications using the terms LSCD, cell-based therapy, cultivated limbal epithelial transplantation (CLET), cultivated oral mucosal epithelial transplantation (COMET),and mesenchymal stem cells from 1989 to August 2022. Inclusion criteria were English language articles.Exclusion criteria were non-English language articles.

Key Content and Findings: current cell-based therapies for LSCD are CLET and non-limbal epithelial cells. Non-limbal epithelial cell methods include COMET, conjunctival epithelial autografts, and mesenchymal stem/stromal cells (MSCs). Moreover, several alternative potential sources of non-limbal cells have described, including induced pluripotent stem cells (iPSCs), human embryonic stem cells (hESCs),human dental pulp stem cells, hair follicle bulge-derived epithelial stem cells, amniotic membrane epithelial cells, and human umbilical cord lining epithelial cells.

Conclusions: Cell-based therapies are a promising treatment modality for LSCD. While CLET is currently the only approved cell-based therapy and is only approved in the European Union, more novel methods have also been shown to be effective in human or animal studies thus far. Non-limbal epithelial cells such as COMET are also an alternative treatment to allogeneic transplants especially as a surface stabilizing procedure. iPSCs are currently being studied in early phase trials and have the potential to revolutionize the way LSCD is treated. Lastly, cell-based therapies for restoring the limbal niche such as mesenchymal stem cells have also shown promising results in the first human proof-of-concept study. Several potential sources of non-limbal cells are under investigation.

Although amniotic membrane transplantation (AMT) has long been used as an essential surgical technique for ocular surface reconstruction, its role continues to evolve and expand. In the management of numerous ocular surface disorders, ranging from inflammatory to infectious, traumatic to neoplastic, the ability to perform AMT is a valuable addition to the skillset of any ophthalmologist. The purpose of this paper is to provide ophthalmologists with an updated, evidence-based review of the clinical indications for AMT in corneal and conjunctival reconstruction, reviewing its common and even experimental applications known to date. The methods of amniotic membrane preservation, the available commercial amniotic membrane products to date, and future directions for amniotic membrane use, including amniotic membrane extract eye drops (AMEED), are also discussed. It is paramount for ophthalmologists to stay up-to-date on the applications of AMT so as to effectively incorporate this versatile treatment modality into their practice,both in the operating room and in the clinic. By familiarizing the general ophthalmologist with its diverse applications, we hope to motivate general ophthalmologists to incorporate the use of AMT into their clinical practice, or provide guidance on how to recognize when referral to a corneal specialist for amniotic membrane application is prudent.

The purpose of this review is to provide a comprehensive and updated overview of the clinical features, imaging modalities, differential diagnosis, diagnostic criteria, and treatment options for Vogt-Koyanagi-Harada (VKH) syndrome, a rare progressive inflammatory condition characterized by bilateral granulomatous panuveitis and systemic manifestations. While the clinical features and disease course of VKH syndrome are well-characterized in the literature, its diagnosis is challenging due to a broad differential that include infectious and noninfectious causes of uveitis and rare inflammatory conditions, as well as a lack of a single diagnostic finding on exam, laboratory testing, or imaging. The evolution of the diagnostic criteria for VKH syndrome reflects the growing understanding of the disease by the ophthalmic community and advancement of imaging technology. Findings on enhanced depth imaging (EDI) optical coherence tomography (OCT) and indocyanine green angiography (ICGA) help detect subtle inflammation of the choroid and were incorporated into new diagnostic criteria developed in the last few years. There is limited research on the treatment for acute VKH, but results of studies to date support the early initiation of immunomodulatory therapy (IMT) due to a high recurrence rate and progression to chronic disease in patients treated with monotherapy with high-dose systemic corticosteroids. This review will provide an in-depth summary of recent literature on advanced imaging modality and IMT to guide clinicians in their management of patients with VKH syndrome.

test 2023-11-07

Background: To compare two swept-source optical coherence tomography (SS-OCT) biometers,IOLMaster 700 and ANTERION.

Methods: This is a retrospective study. Biometric measurements of cataract patients performed between March and July 2021 in the Department of Ophthalmology, United Christian Hospital, Hong Kong, were reviewed. Patients scheduled for cataract surgery were measured with both SS-OCT devices on the same day.The following biometry parameters were compared: keratometry (K), total keratometry (TK), axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), white-to-white (WTW) and the predicted intraocular lens (IOL) power to achieve emmetropia. To assess the agreement between the devices, Bland-Altman analysis with 95% limits of agreement (LoA) were used.

Results: In total, 92 eyes of 47 subjects were measured with both devices. There were statistically significant differences between the two biometers for most measurements (P<0.05) except for flat K, AL and IOL power when using the right eyes for analysis. For the left eyes, there were statistically significant differences in the measurements from the two biometers in all parameters except for flat and steep K. The ANTERION did not obtain ACD, AL and LT in 2 (2.17%), 1 (1.09%) and 5 cases (5.43%) respectively.

Conclusions: The two biometers showed a clinically acceptable agreement in most parameters. Comparisons showed significant differences in most parameters but not clinically relevant except for the TK and WTW, and these two parameters should not be used interchangeably between the devices.

Background: A variety of experimental animal models are used in basic ophthalmological research to elucidate physiological mechanisms of vision and disease pathogenesis. The choice of animal model is based on the measurability of specific parameters or structures, the applicability of clinical measurement technologies, and the similarity to human eye function. Studies of eye pathology usually compare optical parameters between a healthy and altered state, so accurate baseline assessments are critical, but few reports have comprehensively examined the normal anatomical structures and physiological functions in these models.

Methods: Three cynomolgus monkeys, six New Zealand rabbits, ten Sprague Dawley (SD) rats, and BALB/c mice were examined by fundus photography (FP), fundus fluorescein angiography (FFA), and optical coherence tomography (OCT).

Results: Most retinal structures of cynomolgus monkey were anatomically similar to the corresponding human structures as revealed by FP, FFA, and OCT. New Zealand rabbits have large eyeballs, but they have large optic disc and myelinated retinal nerve fibers in their retinas, and the growth pattern of retinal vessels were also different to the human retinas. Unlike monkeys and rabbits, the retinal vessels of SD rats and BALB/c mice were widely distributed and clear. The OCT performance of them were similar with human beings except the macular.

Conclusions: Monkey is a good model to study changes in retinal structure associated with fundus disease, rabbits are not suitable for studies on retinal vessel diseases and optic nerve diseases, and rats and mice are good models for retinal vascular diseases. These measures will help guide the choice of model and measurement technology and reduce the number of experimental animals required.

Background: Benign essential blepharospasm (BEB), aberrant facial nerve degeneration and hemifacial spasm (HFS) are all examples dystonia which, though not life-threatening, can have a significant impact on patient quality of life. The need for reliable self-rating surveys to monitor functional disability is fundamental. The Blepharospasm Disability Index (BSDI) is already a widely utilised and validated self-rating score for blepharospasm whilst the functional disability score (FDS) requires further validation. The principle aim of this study is to repeat validation of the FDS against the BSDI, which has been validated by several groups since its original description but only in patients with BEB.

Methods: A randomised blinded prospective cohort study was conducted at a single unit on 38 patients with BEB, aberrant facial nerve degeneration and HFS. Patients were blinded to complete the FDS followed by the BSDI or the BSDI followed by the FDS with a 30-minute interval.

Results: Both the FDS and BSDI were found to be reliable with high internal consistency and test-retest reliability. Both scales were also found to be moderately correlated with the Jankovic disease severity score.

Conclusions: This study is the first to use the FDS as a rating scale in patients with HFS and aberrant facial nerve degeneration. It is also the first study to formally validate the FDS as an acceptable rating scale for patients with dystonia and in particular it provides validation for its use in patients with HFS and aberrant facial nerve degeneration.

Background and Objective: Ocular surface disease (OSD) is a common yet often overlooked consideration in the management of patients with glaucoma. Although there have been several review articles summarizing the relationship between glaucoma medications and OSD, there is a relative absence of such articles on the effects of glaucoma surgical treatments. Here, we present a comprehensive review of the literature regarding the relationship of glaucoma management and OSD, with an emphasis on surgical considerations.

Methods: PubMed, Google Scholar, and Cochrane Review searches were performed using the following search terms: ocular surface, dry eye, minimally invasive glaucoma surgeries (MIGS), trabeculectomy,glaucoma medications. The titles and abstracts from those searches were screened for relevance to our review topics. Publications were included if the subjects included glaucoma patients, and if ocular surface outcomes were described. Non-English papers were excluded.
Key Content and Findings: Topical glaucoma medications frequently cause adverse effects on the ocular surface, both through direct action of the medications themselves as well as through toxicity from their associated preservatives. Optimization of the ocular surface may improve medication compliance rates.Traditional surgical treatments for glaucoma, such as trabeculectomy, can exacerbate OSD by disrupting the ocular surface but can also reduce the need for chronic medications. Optimization of ocular surface health is imperative in reducing trabeculectomy complication rates, while also potentially reducing the need for trabeculectomy in patients that are able to achieve intraocular pressure control through improved drop tolerability. The introduction of MIGS represents a promising alternative to existing therapies and has been shown to alleviate the overall medication burden. It would be reasonable to assume that decreasing the medication burden could reduce OSD prevalence and severity. However, more research is needed to directly assess the extent of improvement seen after MIGS.

Conclusions: A comprehensive understanding of the importance of OSD in medical and surgical management of glaucoma is essential in optimizing patient care and improving outcomes.