An interventional study of Cord plasma eye drops in Neuropathic Pain and Corneal Disease, sponsored by Singapore Eye Research Institute. Recruiting at 1 site in Singapore. Open to participants aged 21 Years and older. Per ClinicalTrials.gov, last updated 2026-05-05.
Sponsored by Singapore Eye Research Institute · Not applicable, Interventional, and Treatment
The goal of this clinical trial is to investigate the efficacy and work of action of cord plasma eye drops in the treatment of neuropathic corneal pain (NCP). The main question it aims to answer if the cord plasma eye drops are effective for the treatment of NCP through its neurotrophic and anti-neuroinflammatory effects.
Neuropathic corneal pain (NCP) is characterized by dysfunctional corneal nerves and ocular symptoms including pain, discomfort, burning, stinging, allodynia, and photophobia, are typically not relieved by conventional dry eye treatment due to its neurobiological nature. NCP can be associated with systemic diseases, such as diabetes mellitus and trigeminal neuralgia, or various ocular conditions such as severe dry eye disease, herpes simplex keratitis, or post-refractive surgery. The incidence of NCP is approximately 11-13% after refractive surgery (unpublished data), and it is likely to increase with the growing prevalence of dry eye and diabetes mellitus, as well as the growing popularity of ocular surgery. Moreover, the symptoms of NCP can greatly impact the quality of life and can cause a significant psychological and economic burden. It is often refractory to conventional treatments, leading to a significant impact on patients' quality of life and present as a challenge for clinicians seeking effective treatment strategies. The limited effectiveness of existing therapies for NCP has prompted the investigation of novel treatment options, including blood-derived eye drops.
Blood-derived eye drops, including serum-derived and plasma-derived eye drops, have been employed in a variety of clinical applications in ocular surface diseases because of their advantageous qualities and ability to enhance the ocular surface. Blood-derived eye drops can be prepared either from patients' own blood, such as autologous serum tears (AST) and Platelet-rich Plasma, or from allogeneic donors such as Umbilical Cord blood serum. A variety of bioactive compounds packed in blood-derived eye drops have equipped them with neuroprotective and regenerative properties that aid in corneal repair and nerve regeneration. Several mechanisms, including neuroprotection, anti-inflammatory effects, control of neuronal sensitization, and promotion of corneal epithelial repair, have been shown.
The potential efficacy of blood-derived eye drops on NCP has previously been studied. Aggarwal et al. have found that AST treatment reduced NCP patients' symptoms and enhanced the recovery of corneal nerve morphology. AST has also been reported to be beneficial for patients with photoallodynia in NCP. With the treatment with 20% AST, patients' allodynia and photoallodynia symptoms significantly improved within 3.6 months. Moreover, using autologous serum has been shown to reduce the appearance of neuromas and sub-basal corneal nerve beading. Additionally, serum tears have been shown to improve corneal nerve total length and number, as well as to reduce neural reflectivity and nerve tortuosity. Aggarwal et al. further found that the quantity of corneal nerve regeneration following treatment with AST correlated with the improvement in patients' symptoms of NCP. Another study investigated the neurotrophic potential of human platelet lysate (HPL) for corneal nerve regeneration in rat models. HPL has significantly higher concentrations of neurotrophic factors compared with human peripheral serum (HPS), and it showed corneal neurotrophic abilities both in vitro and in vivo. Taken together, blood-derived eye drops provide growth factors and cytokines that support corneal nerve regeneration, suppress ocular surface inflammation, and modulate the pain signaling pathways. However, the detailed mechanisms have not been investigated yet. Studies on the clinical efficacy and molecular profiles of the use of cord plasma eye drops in the treatment of NCP are also lacking.
SNEC has collaborated with Singapore Cord Blood Bank to provide cord blood plasma service, and cord blood plasma eye drops have been used as standard clinical care for patients with ocular surface diseases, severe dry eye, and NCP in SNEC. In the pilot study, the size of corneal neuromas has been found to be decreased after 3-month cord plasma eye drops treatment in patients with NCP (please find section 5 for preliminary data). The present proposal aim to evaluate the clinical efficacy and mechanisms of cord plasma eye drops in the treatment of NCP.
1,100 studies on the registry are indexed under Neuralgia; 241 are open to participants now.
This study's planned enrollment of 20 is below the median of 52 across 831 interventional studies indexed under Neuralgia.
Browse Neuralgia studies →Singapore Eye Research Institute is the lead sponsor of 27 studies on the registry; 12 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients who have been advised and scheduled to receive cord plasma eye drops treatment for their NCP will be recruited. The NCP will be diagnosed based on the following criteria.
Drug: Cord plasma eye drops
SNEC has collaborated with Singapore Cord Blood Bank to provide cord blood plasma service, and cord blood plasma eye drops have been used as standard clinical care for patients with ocular surface diseases, severe dry eye, and NCP in SNEC.
Pain symptoms evaluated by Ocular Pain Assessment Survey (OPAS) questionnaire
Ocular pain will be assessed using the Ocular Pain Assessment Survey (OPAS) questionnaire. The Ocular Pain Assessment Survey (OPAS) is a 27-item questionnaire to evaluate the eye pain from 6 dimensions, including pain intensity for the last 24h, pain intensity for the last 2 weeks, non-eye pain intensity, quality of life, aggravating factors, associated factors and symptom relief. Each question was scored on a scale of 0-10 or 100%, with higher score representing worse pain.
Time frame: 3 months
Corneal nerve morphology assessment by in vivo confocal microscopy (IVCM)
IVCM (Heidelberg Retina Tomography III. Rostock Cornea Module, Heidelberg Engineering GmbH) will be used to examine the subbasal nerve plexus. The images will be analyzed using ACCMetrics software and get the quantitative nerve parameters.
Time frame: 3 months
Tear neuromediator levels
Tear samples will be taken from the wetted Schirmer strips, and will be subjected to neuromediators analysis using enzyme-linked immunosorbent assay (ELISA): Substance P (pg/ml; 6x dilution), CGRP (pg/ml; 4x dilution), and NGF (pg/ml; 1.5x dilution), respectively (CGRP from Phoenix Pharmaceuticals, Runcorn, UK; Substance P and NGF from R\&D Systems, Minneapolis, USA).
Time frame: 3 months
Ocular Surface Disease Index (OSDI) questionnaire to measure eye symptoms and the impact of quality of life.
The Ocular Surface Disease Index (OSDI), a 12-item questionnaire, will be also used to assess the symptoms of dry eye. The OSDI is a 12-item questionnaire that used to assess the eye symptoms and and their impact on vision-related quality of life.
Time frame: 3 months
Amount of tear production measured by Schirmer's I test
Schirmer's I test is a diagnostic method used to measure tear production by placing a standard 5 mm wide Test Strips inside the lower lid margin and assessing the amount of tear absorbed over 5 minutes.
Time frame: 3 months
Corneal sensitivity measurements assessed by Cochet-Bonnet esthesiometer
Corneal sensitivity measurements assess the responsiveness of the cornea to external stimuli using a contact Cochet-Bonnet esthesiometer, which employs a retractable nylon filament marked from 0 to 6 cm. The filament is progressively shortened in 0.5 cm increments until the participant perceives the stimulus. The maximum filament length that successfully triggers a response is recorded in centimeters as a measure of corneal sensitivity.
Time frame: 3 months
Tear film stability
Tear Break-up time (TBUT) will be measured by determining the time interval between a complete blink and the first appearance of a dry spot on the corneal surface, indicating tear film stability.
Time frame: 3 months
National Eye Institute (NEI) Score
The cornea will be divided into five regions, each scored ranging from 0 (no fluorescein staining) to 3 (severe fluorescein staining) according to the grading scheme. The total NEI score will range from 0 to 15.
Time frame: 3 months
Oxford scores
The staining intensity on the ocular surface will be assessed according to the Oxford score scheme: the staining pattern will be graded on a scale from 0 to 5, indicating the intensity from no staining to severe.
Time frame: 3 months
Corneal microneuromas morphology profiles
IVCM will be used to capture images of corneal microneuromas, which are characterized by irregularly shaped enlargements of terminal nerve endings with poorly defined margins and variable hyper-reflectivity. The images containing corneal microneuromas will be manually identified and the total area and perimeter will be quantified using Image J software.
Time frame: 3 months
Abundance of tear proteins assessed by quantitative proteomic analysis
Tear fluid samples will be collected by the strips from Schirmer's I test. Quantitative proteomic analysis technique will be used to measure and compare the abundance of proteins across different samples, providing insights into protein expression, functions, and molecular interactions.
Time frame: 3 months
Plan to share: No
Started Sep 2023 (actual). Primary completion is estimated for Sep 2026, 35 months after the start.
Of 246 non-industry interventional studies with no phase under Neuralgia, half reached primary completion within 24 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 41. This study's planned 35 months is above that.
Counting every sponsor, half of 264 studies reached it within 24 months; a quarter within 10 and three quarters within 41.
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Singapore Eye Research Institute