Corneal Nerve Regeneration after Self-Retained Cryopreserved Amniotic Membrane in Dry Eye Disease

A Narrative Review of Amniotic Membrane Transplantation in Ocular Surface Repair: Unveiling the Immunoregulatory Pathways for Timely Intervention

This narrative review explores the pathophysiology of ocular surface inflammation and highlights the therapeutic potential of patch amniotic membrane transplantation (patch-AMT) in ocular surface repair. Disruptions in ocular surface homeostasis caused by trauma, disease, or immune dysregulation trigger an inflammatory cascade that, if unresolved, can impair epithelial healing, lead to fibrosis, corneal haze, and vision loss. Patch-AMT provides a biological intervention with epitheliotropic, anti-inflammatory, anti-fibrotic, anti-angiogenic, and neuroprotective effects that support wound healing, regulate inflammation, and reduce pain. The review examines patch-AMT's role in acute conditions (chemical burns, Stevens-Johnson Syndrome) and chronic disease (persistent epithelial defects, dry eye disease), focusing on its ability to entrap immune cells, regulate cytokine signaling, and prevent fibrotic remodeling while releasing trophic proteins. Additionally, this review explores how preservation methods, application orientation, and intervention timing influences patch-AMT's efficacy. Recent advancements in non-surgical application methods have expanded accessibility, enabling earlier intervention and outpatient use. However, variability in clinical protocols emphasize the need for standardized guidelines. The review concludes by highlighting the need for further research to refine treatment timing, optimize repeat application strategies, and evaluate cost-effectiveness. While patch-AMT remains underutilized, growing evidence underscores its potential to improve clinical outcomes, particularly when applied early in disease progression.

The Prevalence of Corneal Sensitivity Loss in Patients with and without Dry Eye Disease

Purpose

To assess the prevalence of corneal sensitivity loss in consecutive patients presenting to the clinic as well as in those patients with and without dry eye disease (DED).

Methods

Retrospective, single-center study of consecutive patients who presented to the eye clinic and underwent corneal sensitivity testing using a non-contact esthesiometer. Data included demographics, medical history, prior or current treatments, comorbidities, corneal sensitivity measurements, dry eye symptoms (Standard Patient Evaluation of Eye Dryness Questionnaire [SPEED] questionnaire), and corneal staining scores (Oxford scale). The primary outcome was the prevalence of corneal sensitivity loss, defined as ≥8 mbar. Secondary outcome measures included the prevalence of corneal sensitivity loss in eyes with DED (Oxford ≥2 and SPEED ≥5) and without DED (Oxford ≤1 and SPEED <5).

Results

A total of 395 eyes of 198 patients were included for analysis. Average age was 67.7 ± 16.0 years, and the majority of patients (60.6%) were female. Corneal sensitivity loss was observed in 9.4% of all eyes, and 12.6% of patients had reduced corneal sensitivity in at least one eye. When assessing eyes with signs of DED (Oxford ≥2), 19.7% (13/66) had corneal sensitivity loss. This prevalence increased to 31.4% (11/35) in eyes with both signs and symptoms of DED. Conversely, the prevalence was 5.5% (12/219) in eyes without DED. Binary logistic regression demonstrated that Oxford staining score was the strongest predictor of reduced corneal sensitivity (OR: 2.0, 95% CI: 1.3-3.0, p=0.001), with other significant factors including history of DED, stroke, and herpes zoster virus.

Conclusion

Reduced corneal sensation, a sign of corneal nerve damage and precursor to neurotrophic keratitis, affects nearly 10% of all eyes and 30% of eyes with signs and symptoms of DED. Routine clinical testing of corneal sensation should be implemented, particularly in patients with DED, to ensure early diagnosis and prompt treatment to prevent disease progression.

Overview of Dry Eye Disease for Primary Care Physicians

Dry eye disease (DED), also known as keratoconjunctivitis sicca, is a multifactorial ocular disease characterized by tear film insufficiency due to diverse etiologies including aging, incomplete and infrequent blinking, hormonal changes, medications, and systemic diseases. Classified into aqueous-deficient dry eye (ADDE), evaporative dry eye (EDE), and mixed subtypes, DED presents with symptoms such as irritation, stinging, redness, foreign body sensation, sensitivity to light, and blurred or fluctuating vision. While rare, severe cases may lead to vision loss. With its rising global prevalence across age groups, DED poses a significant public health challenge. Primary care physicians (PCPs), often the first point of contact for DED patients, require timely screening and management strategies. This review explores the epidemiology, pathophysiology, clinical manifestations, diagnosis, and management of DED, emphasizing practical approaches for PCPs. This narrative review was conducted by searching MEDLINE, PubMed, and Google Scholar databases for relevant articles. Diagnostic approaches, including detailed history taking, patient-reported questionnaires, differential diagnosis, and assessments are discussed alongside management strategies, including symptomatic ophthalmic treatment, risk factor mitigation (e.g., reduced digital device screen time), prevention, and nutrition. By providing a synopsis of early symptoms that PCPs are often the first to encounter, practical approaches to screening and managing DED in the primary care setting, and guidelines on when to refer to specialty care, this comprehensive review aims to equip PCPs with the knowledge to improve DED screening and optimize patient outcomes.

Impact of Neurostimulation, Immunomodulation, Topical Medication Application, and Surgical Reconstruction on Corneal Nerve Function and Regeneration

ABSTRACT

The corneal epithelium, supplied by thousands of nerve endings, plays a substantial role in absorbing and distributing nutrients along the ocular surface. Many studies have explored the influence of various modalities in regulating tear production to manage corneal disorders and dry eye disease. These findings have highlighted the advantages of enhancing corneal nerve function and regeneration through neurostimulation, neural signaling, immunomodulation, topical medication application, and surgical reconstruction. The purpose of this narrative review article was to provide an overview of the current state of knowledge on this topic based on a PubMed database literature search for relevant animal and human studies investigating the modification of the trigeminal pathway to restore corneal nerve function and improve overall ocular health. Further investigation into this area of research is important to help guide new therapeutic targets for the prevention and development of treatments of corneal degeneration.

Ultrasound (US)-Guided Perineural Amniotic Membrane and Umbilical Cord Particulate Injections for Iatrogenic Radial Nerve Palsy

Radial nerve injury is a common occurrence in the upper extremities, with various treatment options available such as neurolysis, nerve grafts, or tendon transfers. Recently, amniotic membrane and umbilical cord (AM/UC) particulates have emerged as promising treatments for this type of nerve pathology. Here, we report a new case involving a 24-year-old man who experienced total paralysis of the radial nerve following a humerus shaft fracture. He was treated with peri-nerve injections of AM/UC and underwent an intensive physical rehabilitation program. Three months after the initial injury, significant progress was observed in both motor and sensory functions of his radial nerve.

Application of a practical amniotic membrane ring made on-site for restoration of ocular surface health in dry eye disease

PURPOSE

Dry eye disease (DED) is one of the most common ocular surface disorders worldwide. Despite different underlying pathogenic processes, DED is characterized by ocular surface inflammation, which in turn induces further damage to the corneal epithelium and its underlying structures. Amniotic membrane transplants are known to have potent anti-inflammatory effects and also have the ability to enhance epithelial healing. In this study, we aimed to evaluate the clinical efficacy of amniotic membrane ring (AMR) application in treating refractory dry eye disease.

METHODS

A retrospective analysis of 22 patients treated with contact lens-like amniotic membrane rings was performed. This amniotic membrane ring was formed using an aspiration catheter covered by a large piece of amniotic membrane graft. The amniotic membrane was sutured to the catheter using eight sutures. In this way, a customized amniotic membrane ring was prepared for each patient. Patients' demographics, symptoms, use of medications, conjunctival inflammation, corneal staining, and visual acuity were compared before and after treatment. In addition, the amniotic membrane retention duration, the amniotic membrane's effect on ocular surface healing, follow-up time, and complications were evaluated.

RESULTS

Twenty-eight eyes of 22 patients (18 females and 4 males) aged 53.32±13.36 (6-73) years were included. The AMR retention duration ranged from 5 to 16 days, with a mean of 11±3.09 days, at which time the amniotic membrane had dissolved or been removed inadvertently by the patient. Discomfort with the ring was seen in 1 of 28 eyes (3.6%). The patients reported symptomatic relief for a period of 3.64±1.25 months. Symptomatic relief was accompanied by a reduction of OSDI scores (from 63.39±17.24 to 33.19±12.45) (P<0.001), use of topical medications (from 4.21±1.03 to 2.42±0.50) (P<0.001), conjunctival hyperemia (from 1.57±1.19 to 0.35±0.48) (P<0.001), corneal staining (from 2.89±1.16 to 0.57±0.74) (P<0.001), and improvement in visual acuity (from 0.23±0.16 to 0.16±0.25 logMAR) (P=0.001).

CONCLUSIONS

Amniotic membrane ring treatment might be used to treat refractory dry eye disease. This technique has an economic advantage over other commercially available amniotic bandage tissues and can be easily removed and replaced during a follow-up examination.

Dr. Scheffer C.G. Tseng: A Pioneer in Cryopreserved Amniotic Membrane for Regenerative Medicine

Dr. Scheffer Chuei-Goong Tseng is widely recognized as a pioneer in the development and application of cryopreserved amniotic membrane therapy. Dr. Tseng has completely revolutionized the management of ocular and various diseases through the success in the study of regenerative medicine, specifically through the human amniotic membrane. He has turned innovative scientific discoveries into products that contribute to many medical fields, including ophthalmology, orthopedics, oral and maxillofacial surgery, dermatology, and wound care. This review article explores Dr. Tseng's background, career, and significant contributions to regenerative medicine, with a particular focus on the impact of cryopreserved amniotic membrane technology.

Evaluating the efficacy and safety of therapeutic interventions for corneal neuropathy: A systematic review

Corneal neuropathy involves corneal nerve damage that disrupts ocular surface integrity, negatively impacting quality-of-life from pain and impaired vision. Any ocular or systemic condition that damages the trigeminal nerve can lead to corneal neuropathy. However, the condition currently does not have standardized diagnostic criteria or treatment protocols. The primary aim of this systematic review was to evaluate the efficacy and safety of interventions for treating corneal neuropathy. Randomized controlled trials (RCTs) that investigated corneal neuropathy treatments were eligible if the intervention(s) was compared to a placebo or active comparator. Comprehensive searches were conducted in Ovid MEDLINE, Ovid Embase and clinical trial registries from inception to July 2022. The Cochrane Risk-of-Bias 2 tool was used to assess study methodological quality. Certainty of the body of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Overall, 20 RCTs were included. Evaluated interventions comprised regenerative therapies (n = 6 studies), dietary supplements (n = 4), anti-glycemic agents (n = 3), combination therapy (n = 3), supportive therapies (n = 2) and systemic pain pharmacotherapies (n = 2). Nine RCTs were judged at high risk of bias for most outcomes. Definitions for corneal neuropathy in the populations varied substantially across studies, consistent with lack of consensus on diagnostic criteria. A diverse range of outcomes were quantified, likely reflecting absence of an agreed core outcome set. There was insufficient evidence to draw definitive conclusions on the efficacy or safety of any intervention. There was low or very low certainty evidence for several neuroregenerative agents and dietary supplements for improving corneal nerve fiber length in corneal neuropathy due to dry eye disease and diabetes. Low or very low certainty evidence was found for neuroregenerative therapies and dietary supplements not altering corneal immune cell density. This review identifies a need to standardize the clinical definition of corneal neuropathy and define a minimum set of core outcome measures. Together, this will provide a foundation for improved phenotyping of clinical populations in studies, and improve the capacity to synthesize data to inform evidence-based care. Protocol registration: PROSPERO ID: CRD42022348475.

Sutureless Dehydrated Amniotic Membrane (Omnigen) Application Using a Specialised Bandage Contact Lens (OmniLenz) for the Treatment of Dry Eye Disease: A 6-Month Randomised Control Trial

Background and Objectives: Dry Eye Disease (DED) is a chronic condition characterised by tear film instability and ocular surface disruption, significantly impacting patients' quality of life. This study aimed to provide top-level clinical evidence for the long-term efficacy of dehydrated amniotic membrane (dAM, Omnigen®) delivered via a specialised bandage contact lens (sBCL, OmniLenz) for managing moderate-to-severe DED. Materials and Methods: This randomised controlled trial (NCT04553432) involved 93 participants with moderate-to-severe DED, randomised to receive a 1-week bilateral treatment of either dAM (17 mm diameter with 6 mm central 'window') applied under a sBCL or sBCL alone. Participants were assessed at baseline and followed up at 1, 3, and 6 months post-treatment. Outcomes included changes in symptomatology, tear film and ocular surface measurements, and in vivo confocal microscopy imaging of corneal nerve parameters and corneal dendritic cell (CDC) counts. Results: The dAM-sBCL group demonstrated a 65% reduction in OSDI scores at 6 months (p < 0.001), with 88% of participants showing improvement at 1 month. Corneal staining was significantly reduced in both groups. dAM-sBCL provided significant improvements in corneal nerve parameters at 1 month, with sustained positive trends at 3 months. Additionally, dAM-sBCL significantly reduced mature CDC counts, suggesting an anti-inflammatory effect. Conclusions: Treatment with dAM-sBCL for just 1 week significantly and rapidly improved dry eye symptoms as well as ocular surface signs for at least 3 months. It also enhanced corneal nerve health while reducing activated/mature corneal inflammatory cell numbers, presenting a safe and promising new treatment for moderate-to-severe DED.

Bilateral Sutureless Application of Human Dehydrated Amniotic Membrane with a Specialised Bandage Contact Lens for Moderate-to-Severe Dry Eye Disease: A Prospective Study with 1-Month Follow-Up

Purpose

To assess changes in symptoms and ocular surface signs following a bilateral sutureless treatment of dehydrated amniotic membrane (dAM) under a specialised bandage contact lens (sBCL) in patients with moderate-to-severe dry eye disease (DED).

Patients and Methods

In this prospective pre-post interventional study, 35 patients diagnosed with moderate-to-severe DED, with an Ocular Surface Disease Index (OSDI) score >30 on current treatment, were enrolled. Assessments were conducted at baseline (day -30), after 30 days run-in with no additional treatment (day 0 - control), and 30 days post sBCL+dAM treatment (day 30 - treatment). Intervention involved two successive bilateral 4-5 day sutureless applications of dAM (17mm diameter, with a 6 mm central aperture, Omnigen® VIEW) under an 18mm sBCL (OmniLenz®). Symptomatology and ocular signs were measured using OSDI, Dry Eye Questionnaire-5 (DEQ-5), Symptom Assessment iN Dry Eye (SANDE), and other ocular surface health indicators including non-invasive breakup time, corneal and conjunctival staining, and lid wiper epitheliopathy length and width (LWE).

Results

While symptomatology remained stable during the 30-day no-treatment run-in, 1-month post-dAM treatment, there was a significant reduction in OSDI scores (from 55.8 to 32.3, p<0.001), DEQ-5 (from 14.6 to 10.0, p<0.001), SANDE frequency (from 65.2 to 43.6, p<0.001), and SANDE severity (from 59.8 to 41.1, p<0.001). Additionally, there was a notable decrease in the width of LWE staining, from grade 2 (50-75% of the lid wiper) to grade 1 (25-50% of the lid wiper) (p=0.011).

Conclusion

A bilateral 8-10-day treatment duration with dAM applied with sBCL demonstrated a 31 to 42% improvement in symptomatology and a decrease in ocular surface signs of mechanical stress. This innovative bilateral treatment approach offers a promising treatment modality for patients with refractory moderate-to-severe DED.

Neurophysiology of corneal neuropathic pain and emerging pharmacotherapeutics

The altered activity generated by corneal neuronal injury can result in morphological and physiological changes in the architecture of synaptic connections in the nervous system. These changes can alter the sensitivity of neurons (both second-order and higher-order projection) projecting pain signals. A complex process involving different cell types, molecules, nerves, dendritic cells, neurokines, neuropeptides, and axon guidance molecules causes a high level of sensory rearrangement, which is germane to all the phases in the pathomechanism of corneal neuropathic pain. Immune cells migrating to the region of nerve injury assist in pain generation by secreting neurokines that ensure nerve depolarization. Furthermore, excitability in the central pain pathway is perpetuated by local activation of microglia in the trigeminal ganglion and alterations of the descending inhibitory modulation for corneal pain arriving from central nervous system. Corneal neuropathic pain may be facilitated by dysfunctional structures in the central somatosensory nervous system due to a lesion, altered synaptogenesis, or genetic abnormality. Understanding these important pathways will provide novel therapeutic insight.

Association of Treatment Duration and Clinical Outcomes in Dry Eye Treatment with Sutureless Cryopreserved Amniotic Membrane

Background

While sutureless, cryopreserved amniotic membrane (cAM) has been shown to significantly improve signs and symptoms of dry eye disease (DED), no studies have assessed the association of cAM treatment duration to the differential response in clinical outcomes.

Methods

A multi-center, retrospective study was conducted on patients with moderate-to-severe DED who were treated with self-retained cAM (Prokera® Slim) for 2 to 7 days. The primary outcome measure was DEWS severity score assessed at 1 week, 1 month, and 3 months. Secondary outcome measures included ocular discomfort, visual symptoms, corneal staining, and visual acuity.

Results

A total of 89 eyes (77 patients) with moderate-to-severe DED (DEWS severity 3.24 ± 0.56) received treatment with self-retained cAM for 2 days (n = 10), 3 days (n = 15), 4 days (n = 12), 5 days (n = 19), 6 days (n = 6), or 7 days (n = 27). DEWS scores significantly improved at 1 week, 1 month, and 3 months for all treatment duration groups, with no significant difference observed between groups at any timepoint. In addition to an improvement in DEWS severity scores, those receiving cAM treatment for 2 days demonstrated a significant improvement in corneal staining, visual symptoms, and ocular discomfort at 1 week, 1 month, and 3 months.

Conclusion

This retrospective study suggests that a single placement of self-retained cAM for 2 days can significantly improve signs and symptoms of DED with a lasting benefit observed for up to 3 months.

Solving STODS-Surgical Temporary Ocular Discomfort Syndrome

The term STODS (Surgical Temporary Ocular Discomfort Syndrome) has been coined to describe the ocular surface perturbations induced by surgery. As one of the most important refractive elements of the eye, Guided Ocular Surface and Lid Disease (GOLD) optimization is fundamental to success in achieving refractive outcomes and mitigating STODS. Effective GOLD optimization and the prevention/treatment of STODS requires an understanding of the molecular, cellular, and anatomic factors that influence ocular surface microenvironment and the associated perturbations induced by surgical intervention. By reviewing the current understanding of STODS etiologies, we will attempt to outline a rationale for a tailored GOLD optimization depending on the ocular surgical insult. With a bench-to-bedside approach, we will highlight clinical examples of effective GOLD perioperative optimization that can mitigate STODS' deleterious effect on preoperative imaging and postoperative healing.

Clinical Outcomes of Amniotic Membrane/Umbilical Cord Particulate in Spinal Disorders: A Retrospective Study

Background

Musculoskeletal spinal disorders significantly impact patient populations from everyday workers to military soldiers. Effective treatment is critical to minimize the time between injury and returning to work and daily activities. Injection of amniotic membrane/umbilical cord (AMUC) tissue has demonstrated great potential in reducing patients' pain and has become an increasingly popular treatment option for painful orthopedic disorders.

Methods

A single-center, retrospective study was conducted on patients diagnosed with musculoskeletal spinal disorders and subsequently treated with AMUC via epidural and facet injections. Demographics and outcomes related to pain were assessed. Pain was verbally reported by the patient on a scale of 0-10 where 0 indicated no pain and 10 indicated worst imaginable pain. Complications and adverse events were also reported.

Results

A total of 52 patients (average age 40.8 ± 9.6 years) were included in the analysis with diagnoses of spondylosis (n = 44), intervertebral disc degeneration (n = 31), radiculopathy (n = 18), stenosis (n = 2), or other conditions. The cohort's average baseline pain score was 4.9 ± 2.2 with a mean duration of symptoms for 54.2 months (range: 1-300 months). After AMUC injection, pain significantly decreased to 3.4 ± 2.3 at two weeks (p < 0.0001) and 3.5 ± 2.2 at 3-4 weeks (p = 0.0023). For the mean follow-up period of 10.6 ± 5.4 weeks, pain was reduced to 2.8 ± 2.1 (p < 0.0001 vs baseline). No significant complications or adverse events were reported.

Conclusion

Use of an injectable AMUC, such as CLARIX FLO, may alleviate pain in patients with painful spinal indications of various pathologies. This study provides further evidence of its safety and efficacy in epidural and facet injections. Further studies are warranted to verify these promising results.

Effects of Amniotic Membrane Extract Eye Drops on Persistent Epithelial Defects of the Cornea

Purpose: To evaluate the clinical efficacy of amniotic membrane extract eye drops (AMEEDs) in patients with persistent epithelial defects (PEDs) of the cornea.Methods: Sixteen patients with PEDs refractory to the conventional treatment were further treated with AMEEDs six times a day. Visual acuity, visual analog scale (VAS), esthesiometer score, and areas of the epithelial defects before and after 1 and 2 months of treatment were evaluated. After 2 months, AMEEDs were considered effective if all epithelial defects were healed, partially effective if the epithelial defects decreased in size compared with the baseline, and ineffective if the epithelial defects increased in size and required additional treatment.Results: After 2 months of treatment with AMEEDs, there was a reduction in the area of epithelial defects (5.2 ± 3.1 mm2 vs. 0.1 ± 0.1 mm2, respectively, p = 0.01), as well as a significant improvement in best-corrected visual acuity (0.8 ± 0.5 logarithm of minimal angle of resolution [LogMAR] vs. 0.6 ± 0.3 LogMAR, respectively, p = 0.03), and VAS scores (4.3 ± 1.0 vs. 2.8 ± 0.7, respectively, p = 0.04) compared with the baseline values. Treatment with AMEEDs was effective in 13 (81.3%) patients and partially effective in three (18.8%) patients.Conclusions: AMEEDs could stimulate epithelial wound healing and improve ocular symptoms in patients with refractory PED. Therefore, AMEEDs could be considered an effective treatment option for refractory PEDs.

Alterations in corneal nerves in different subtypes of dry eye disease: An in vivo confocal microscopy study

PURPOSE

To evaluate corneal subbasal nerve alterations in evaporative and aqueous-deficient dry eye disease (DED) as compared to controls.

METHODS

In this retrospective, cross-sectional, controlled study, eyes with a tear break-up time of less than 10 s were classified as DED. Those with an anesthetized Schirmer's strip of less than 5 mm were classified as aqueous-deficient DED. Three representative in vivo confocal microscopy images were graded for each subject for total, main, and branch nerve density and numbers.

RESULTS

Compared to 42 healthy subjects (42 eyes), the 70 patients with DED (139 eyes) showed lower total (18,579.0 ± 687.7 μm/mm2 vs. 21,014.7 ± 706.5, p = 0.026) and main (7,718.9 ± 273.9 vs. 9,561.4 ± 369.8, p < 0.001) nerve density, as well as lower total (15.5 ± 0.7/frame vs. 20.5 ± 1.3, p = 0.001), main (3.0 ± 0.1 vs. 3.8 ± 0.2, p = 0.001) and branch (12.5 ± 0.7 vs. 16.5 ± 1.2, p = 0.004) nerve numbers. Compared to the evaporative DED group, the aqueous-deficient DED group showed reduced total nerve density (19,969.9 ± 830.7 vs. 15,942.2 ± 1,135.7, p = 0.006), branch nerve density (11,964.9 ± 749.8 vs. 8,765.9 ± 798.5, p = 0.006), total nerves number (16.9 ± 0.8/frame vs. 13.0 ± 1.2, p = 0.002), and branch nerve number (13.8 ± 0.8 vs. 10.2 ± 1.1, p = 0.002).

CONCLUSIONS

Patients with DED demonstrate compromised corneal subbasal nerves, which is more pronounced in aqueous-deficient DED. This suggests a role for neurosensory abnormalities in the pathophysiology of DED.

The management of neurotrophic keratitis

PURPOSE OF REVIEW

The management of neurotrophic keratitis (NK) has evolved in the last decade. The present article reviews updated management guidelines of this entity, as well as future innovations in the field.

RECENT FINDINGS

The advent of confocal microscopy has allowed for the first time to image corneal nerves. In addition, multiple novel topical treatments such as nerve growth factor have improved the prognosis of this disease, with many other in the pipeline. Finally, corneal nerve restoration is now possible with corneal neurotization procedures.

SUMMARY

Many novel treatments based on agents that stimulate nerve regrowth are now available to treat NK. Improvement in neurotization procedures could also address advanced stages of this disease with surgery.

A Review of Imaging Biomarkers of the Ocular Surface

A biomarker is a "characteristic that is measured as an indicator of normal biological processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions." Recently, calls for biomarkers for ocular surface diseases have increased, and advancements in imaging technologies have aided in allowing imaging biomarkers to serve as a potential solution for this need. This review focuses on the state of imaging biomarkers for ocular surface diseases, specifically non-invasive tear break-up time (NIBUT), tear meniscus measurement and corneal epithelial thickness with anterior segment optical coherence tomography (OCT), meibomian gland morphology with infrared meibography and in vivo confocal microscopy (IVCM), ocular redness with grading scales, and cellular corneal immune cells and nerve assessment by IVCM. Extensive literature review was performed for analytical and clinical validation that currently exists for potential imaging biomarkers. Our summary suggests that the reported analytical and clinical validation state for potential imaging biomarkers is broad, with some having good to excellent intra- and intergrader agreement to date. Examples of these include NIBUT for dry eye disease, ocular redness grading scales, and detection of corneal immune cells by IVCM for grading and monitoring inflammation. Further examples are nerve assessment by IVCM for monitoring severity of diabetes mellitus and neurotrophic keratitis, and corneal epithelial thickness assessment with anterior segment OCT for the diagnosis of early keratoconus. However, additional analytical validation for these biomarkers is required before clinical application as a biomarker.

Cost utility analysis of cryopreserved amniotic membrane versus topical cyclosporine for the treatment of moderate to severe dry eye syndrome

BACKGROUND

The purpose is to perform a cost effectiveness analysis amniotic membrane vs. topical medications in the use of treating dry eye disease. A cost effectiveness analysis comparing amniotic membrane + other topical medications to topical cyclosporine A + other topical medications was evaluated using accepted decision tree modeling software.

METHODS

TreeAge Pro 2019 software was used to evaluate the base case costs over a one year timeframe. Sensitivity analysis was performed on those variables which had the greatest effect on choosing one therapy versus the other based on cost. Monte Carlo simulation was run 1,000 times to determine the most effective, least costly alternative. Costs were evaluated from a societal level (direct + indirect). Quality of life utility scores were evaluated using known time tradeoffs from prior studies (scale 0-1; with 1 being perfect vision).

RESULTS

Over a one year timeframe, the base case demonstrated that amniotic membrane + topical medications was the less expensive alternative and provided for incremental utilities versus topical cyclosporine + other medications (Cost/utility: $18,275/0.78 vs. $20,740/0.74). If examining direct costs only, topical cyclosporine was the least expensive option over a one year timeframe: $4,112 vs. $10,300. Sensitivity analysis demonstrated that in order for topical cyclosporine to be the less expensive alternative the following variables would need to be: < 68 days productivity lost; < $161 productivity lost/day; > 79% of amniotic membrane implants would need to be re-implanted at month 4 (for whatever reason); > $2677 per amniotic membrane implant procedure (Medicare reimbursement rate); > 96% positive response to topical cyclosporine A at month 4; > 58% positive response to topical cyclosporine A at month 6 and; < 54% probability clinical improvement with amniotic membrane. Monte Carlo simulation demonstrated that amniotic membrane was the less costly, most effective alternative 91.5% of the time.

CONCLUSION

Based on improved outcomes using amniotic membrane, patient productivity was improved resulting in lower societal costs (less days lost from work). When considering the untoward effects of dry eye disease on societal costs, an improvement of the dry eye disease condition was accomplished most often with amniotic membrane.

An algorithm for the preoperative diagnosis and treatment of ocular surface disorders

Any ocular surface disease (OSD), but most commonly, dry-eye disease (DED), can reduce visual quality and quantity and adversely affect refractive measurements before keratorefractive and phacorefractive surgeries. In addition, ocular surgery can exacerbate or induce OSD, leading to worsened vision, increased symptoms, and overall dissatisfaction postoperatively. Although most respondents of the recent annual American Society of Cataract and Refractive Surgery (ASCRS) Clinical Survey recognized the importance of DED on surgical outcomes, many were unaware of the current guidelines and most were not using modern diagnostic tests and advanced treatments. To address these educational gaps, the ASCRS Cornea Clinical Committee developed a new consensus-based practical diagnostic OSD algorithm to aid surgeons in efficiently diagnosing and treating visually significant OSD before any form of refractive surgery is performed. By treating OSD preoperatively, postoperative visual outcomes and patient satisfaction can be significantly improved.

Niche regulation of limbal epithelial stem cells: HC-HA/PTX3 as surrogate matrix niche

Homeostasis of the corneal epithelium is ultimately maintained by stem cells that reside in a specialized microenvironment within the corneal limbus termed palisades of Vogt. This limbal niche nourishes, protects, and regulates quiescence, self-renewal, and fate decision of limbal epithelial stem/progenitor cells (LEPCs) toward corneal epithelial differentiation. This review focuses on our current understanding of the mechanism by which limbal (stromal) niche cells (LNCs) regulate the aforementioned functions of LEPCs. Based on our discovery and characterization of a unique extracellular matrix termed HC-HA/PTX3 (Heavy chain (HC1)-hyaluronan (HA)/pentraxin 3 (PTX3) complex, "-" denotes covalent linkage; "/" denotes non-covalent binding) in the birth tissue, i.e., amniotic membrane and umbilical cord, we put forth a new paradigm that HC-HA/PTX3 serves as a surrogate matrix niche by maintaining the in vivo nuclear Pax6+ neural crest progenitor phenotype to support quiescence and self-renewal but prevent corneal fate decision of LEPCs. This new paradigm helps explain how limbal stem cell deficiency (LSCD) develops in aniridia due to Pax6-haplotype deficiency and further explains why transplantation of HC-HA/PTX3-containing amniotic membrane prevents LSCD in acute chemical burns and Stevens Johnson syndrome, augments the success of autologous LEPCs transplantation in patients suffering from partial or total LSCD, and assists ex vivo expansion (engineering) of a graft containing LEPCs. We thus envisage that this new paradigm based on regenerative matrix HC-HA/PTX3 as a surrogate niche can set a new standard for regenerative medicine in and beyond ophthalmology.

Amniotic Membrane Transplantation in Ophthalmology: An Updated Perspective

Aim

The aim of this paper is to provide a succinct literature review of the different clinical applications for AMT usage in an ophthalmic setting, ranging from commonly used applications to less mainstream approaches. The hope is that this review enables the reader to have a better understanding of the biological properties of amnion as well as the indications and scenarios in which AMT can be used, whilst presenting relevant evidence from within the literature which may be of interest. We also provide an update on the methods of preservation of amniotic membrane and the application methodologies.

Methods

Literature search. A PubMed search was performed using the search terms “amniotic membrane transplant”, “amnion AND cornea”, amnion AND ophthalmology”, “amnion AND ocular surface” and “Amnion AND eye”. A full review of the literature using the PubMed database was conducted up until 01/05/20. The articles used were written in English, with all articles accessed in full. Both review articles and original articles were used for this review. All full publications related to ophthalmology were considered.

Self-Retained Cryopreserved Amniotic Membrane for the Management of Corneal Ulcers

Purpose

To evaluate the clinical outcomes of self-retained cryopreserved amniotic membrane (cAM) for the treatment of corneal ulcers.

Methods

This was a single-center, retrospective review of consecutive patients with non-healing corneal ulcers that underwent treatment with self-retained cAM (PROKERA^® Slim). The primary outcome measure was time to complete corneal epithelialization. Ocular discomfort, corneal staining, corneal signs, and visual acuity were assessed at 1 week, 1 month, 3 months, and 6 months. Complications, adverse events, and ulcer recurrence were also recorded.

Results

A total of 13 eyes (13 patients) with recalcitrant corneal ulcers were included for analysis, 9 (69%) of which progressed from neurotrophic keratitis (NK). Prior to cAM application, patients used conventional treatments such as artificial tears (n = 11), antibiotics (n = 11), ointment (n = 11), steroids (n = 6), and antivirals (n = 3). Self-retained cAMs (n = 1.5 ± 0.8) were placed for 6.8 ± 3.4 days, during which time antibiotics were continued. Four cases (31%) were subsequently treated with bandage contact lens (n = 3) and tarsorrhaphy (n = 1). All corneal ulcers healed in a median of 14 days (range: 4-43). This was accompanied by a significant improvement in ocular discomfort, corneal staining, and corneal signs at 1 week, 1 month, 3 months, and 6 months (P<.05). Recurrence was noted in one case. No adverse events were observed.

Conclusion

Self-retained cAM may be a valuable, in-office treatment option for healing recalcitrant corneal ulcers of various etiologies, especially those with underlying NK. Further prospective, controlled studies are warranted.

Amniotic membrane transplantation for managing dry eye and neurotrophic keratitis

Neurotrophic keratitis (NK), a degenerative disease caused by damage to the trigeminal nerve, abolishes both tearing and blinking reflexes, thus causing the most severe forms of dry eye disease (DED). Conversely, the increasing severity of DED also leads to progressive loss of corneal nerve density, potentially resulting in NK. Both diseases manifest the same spectrum of corneal pathologies including inflammation and corneal epithelial keratitis, which can progress into vision-threatening epithelial defect and stromal ulceration. This review summarizes the current literature regarding outcomes following sutured and sutureless cryopreserved amniotic membrane (AM) in treating DED as well as epithelial defects and corneal ulcers due to underlying NK. These studies collectively support the safety and effectiveness of cryopreserved AM in restoring corneal epithelial health, improving visual acuity in eyes with NK and DED, and alleviating symptomatic DED. Future randomized controlled trials are warranted to validate the above findings and determine whether such clinical efficacy lies in promoting corneal nerve regeneration.

Basic science review of birth tissue uses in ophthalmology

The birth tissue is predominantly comprised of amniotic membrane (AM) and umbilical cord (UC), which share the same cell origin as the fetus. These versatile biological tissues have been used to treat a wide range of conjunctival and corneal conditions since 1940. The therapeutic benefits of the birth tissue stem from its anti-inflammatory and anti-scarring properties that orchestrate regenerative healing. Although the birth tissue also contains many cytokines, growth factors, and proteins, the heavy chain 1-hyaluronic acid/pentraxin 3 (HC-HA/PTX3) matrix has been identified to be a major active tissue component responsible for AM/UC's multifactorial therapeutic actions. HC-HA/PTX3 complex is abundantly present in fresh and cryopreserved AM/UC, but not in dehydrated tissue. In this review, we discuss the tissue anatomy, the molecular mechanism of action based on HC-HA/ PTX3 to explain their therapeutic potentials, and the various forms available in ophthalmology.

A single-center, retrospective review of robot-assisted laparoscopic prostatectomy with and without cryopreserved umbilical cord allograft in improving continence recovery

The objective of this study was to evaluate the safety and effectiveness of cryopreserved umbilical cord (UC) allograft as a nerve wrap around the neurovascular bundle (NVB) in accelerating return to continence after radical prostatectomy. A single-center, retrospective study was performed on 200 patients who underwent bilateral, nerve-sparing robot-assisted radical prostatectomy (RARP) with and without placement of UC around the NVBs (n = 100/group). Patients were excluded if they had previous simple or transurethral prostatectomy or history of pelvic radiation. Post-operative continence, defined as 0 or 1 safety pad, was analyzed between groups at 1, 3, 6, and 12 months. Complications, biochemical recurrence and adverse events were assessed to determine safety. Patients who underwent RARP with UC were significantly more likely to be continent at 1 month (65% vs. 44%, p = 0.018), 3 months (83% vs. 70%, p = 0.03), and 12 months (97% vs. 87%, p = 0.009). Sample stratification revealed that UC is beneficial for obese patients and those > 60 years, both of which are high risk for post-RARP incontinence. Biochemical failure was noted in 2 (UC) and 4 (control) patients. No adverse events or complications related to UC were observed. The results suggest that UC allograft is safe and accelerates continence recovery in post-RARP patients. Prospective, randomized trials are warranted.

Safety and efficacy of amniotic cytokine extract in the treatment of dry eye disease

Purpose: Evaluate the safety and efficacy of cryopreserved amniotic cytokine extract (ACE) in the treatment of subjects with dry eye disease (DED). Patients and methods: This was a retrospective, multicenter, chart review of adult patients with DED that instilled cryopreserved ACE drops twice-daily for 4 or 12 weeks. Patients had corneal fluorescein staining (0-20 range) and/or a lissamine green conjunctival staining score (0-18 range) of ≥3 and ≤9 in at least 1 eye and a score ≥40 (0-100 range) of eye dryness/irritation on a visual analog scale (VAS). Following completion of a treatment course, medical records were reviewed from the initiation of therapy (baseline), and at post-treatment visits (4 weeks, 8 weeks, and 12 weeks). Patient records for visual acuity, adverse events, corneal fluorescein staining, conjunctival lissamine green staining, and symptom scores of ocular dryness/irritation were reviewed for each visit, as available. Safety and tolerability were assessed through the evaluation of patient-reported adverse events recorded in the medical records. Results: A total of 54 eligible patients were identified at 7 clinical sites; 16 patients administered ACE drops for 4-weeks, and 38 patients instilled ACE drops for 12 weeks. Significant improvements in the mean changes from baseline were observed for corneal fluorescein staining, lissamine green staining, visual acuity (LogMar) and VAS ocular symptom scores at the 4-week post-treatment visit (p<0.01). Additional improvements continued out to the 12-week follow-up assessment visits. Two patients discontinued therapy due to reports of ocular burning or foreign body sensation. Conclusion: The cryopreserved ACE formulation was well-tolerated and effective in reducing the clinical signs and symptoms of DED. Conduct of a vehicle-controlled prospective study is warranted.

Update on corneal neurotisation

Corneal neurotisation describes surgical restoration of nerve growth into the cornea to restore corneal sensation and trophic function. It represents an exciting and effective emerging treatment for neurotrophic keratopathy. Techniques described to date involve either direct nerve transfer or an interpositional nerve graft coapted to a healthy donor nerve. We review the experience to date with particular emphasis on a detailed review of techniques, outcomes and current thoughts.

Treatment outcomes in the DRy Eye Amniotic Membrane (DREAM) study

Purpose

To evaluate the efficacy of cryopreserved amniotic membrane (CAM) in reducing signs and symptoms of dry eye disease (DED) in a large patient population.

Methods

A retrospective chart review at 10 clinical sites was done of patients with refractory DED who received CAM and completed at least 3 months of follow-up. Data collected were demographics; medical history including previous and current ocular treatment, diagnosis, clinical presentations, comorbidity, duration and frequency of treatment with CAM; and concomitant medications. The primary outcome was the change in dry eye workshop (DEWS) score after treatment.

Results

A total of 97 eyes of 84 patients exhibited severe dry eye despite maximal medical treatments including topical artificial tears, cyclosporine-A, serum, antibiotics, and steroids. Patients manifested with superficial punctate keratitis (86%), filamentary keratitis (13%), exposure keratitis (19%), neurotrophic keratitis (2%), and corneal epithelial defect (7%). After CAM treatment for 5.4±2.8 days, 74 (88%) patients demonstrated an improved ocular surface along with a notable reduction of the severity as the overall DEWS score was significantly reduced from 3.25±0.5 at baseline to 1.44±0.6 at 1 week, 1.45±0.6 at 1 month, and 1.47±0.6 at 3 months (p<0.001). Ten eyes (10%) required repeated treatment to complete healing. Apart from discomfort during CAM placement, there were no adverse events.

Conclusion

Placement of CAM is promising to enhance the recovery of ocular surface health and reduce signs and symptoms in patients with moderate-to-severe DED.