Limbal Deficiency Research Articles

Management of Ocular Surface Inflammation with Persistent Epithelial Defects Using a Sutureless Human Amniotic Membrane Dehydrated Matrix: A Prospective Study Utilizing a Digital Ocular Surface Assessment Tool.

To report the outcomes of using a sutureless human amniotic membrane dehydrated matrix (HAMDM) in the management of a range of ocular surface conditions utilizing a digital ocular surface disease assessment tool. Two UK NHS Trusts - Queen Victoria Hospital Foundation Trust (East Grinstead and Maidstone) and Tunbridge Wells Trust (Kent) - prospectively treated patients with ocular surface disease with sutureless HAMDM. The patient cohort was assessed for resolution of epithelial defects, ocular surface inflammation, and best-corrected visual acuity pre- and posttreatment. Measurements of ocular surface inflammation and epithelial defect size were assessed using AOS digital imaging software, a validated tool for objective grading of bulbar conjunctival redness and measurement of corneal epithelial defects. A total of 47 applications of sutureless HAMDM on 46 eyes of 46 patients (25 male, 21 female, age 9-94 years) were assessed across various etiologies for an average of 24.0±14.1 days. Patients with limbal stem-cell deficiency (n=17), persistent epithelial defects (n=16), neurotrophic corneal disease (n=7), filamentary keratitis (n=2), corneal erosion (n=1), corneal thinning (n=1), ocular surface inflammation (n=1), and traumatic corneal laceration (n=1) were included in the study. Across all patents, 63% of eyes showed complete healing of epithelial defects and 32.6% of eyes showed partial resolution. The average rate of healing (wound closure) was 0.36 mm2 per day across the overall patient cohort, and the rate of healing in cases with complete resolution of epithelial defects was 0.41 mm2 per day. Inflammation across all four quadrants of the ocular surface remained stable. Visual acuity across the patient cohort remained stable (61%) and improved in 26% of patients (0.06±0.51 logMAR). Sutureless HAMDM application can be accomplished in just a few minutes and effectively treat a range of ocular surface disease in a clinical, nonsurgical setting. The AOS imaging software offered a quantitative methodology for measuring epithelial defect size and inflammation state.

Atopic Keratoconjunctivitis: Pathophysiology, Clinic, and Potential New Therapeutic Concepts.

Atopic dermatitis (AD) is a chronic recurrent inflammatory skin disease with a bipolar age distribution in childhood, adolescence and middle adulthood. Up to 50% of AD patients show ocular involvement, which can be potentially sight threatening. Clinically, the majority of cases present with atopic blepharo(kerato)conjunctivitis or atopic keratoconjunctivitis (AKC); other clinical variants from this group of inflammatory ocular surface diseases are keratoconjunctivitis vernalis in childhood and adolescence and allergic conjunctivitis. In addition to the aforementioned blepharitis, keratitis and conjunctivitis, AD is also associated with eyelid involvement with subsequent eyelid malposition, limbal insufficiency with the development of pseudopterygia, (chronic) cicatrizing conjunctivitis with symblephara formation and fornix shortening, as well as ocular surface malignancies such as conjunctival intraepithelial neoplasia (CIN) and squamous cell carcinoma. In addition, an association with AD or AKC has been described for keratoconus. Whereas the therapy of AD in dermatology has made revolutionary advances in recent years through the use of biologicals, the primary use of these biologicals in ophthalmological complications is still very hesitant. Treatment here is often provided using topical steroids and calcineurin inhibitors. The following article summarises recent developments in basic and clinical dermatological research and discusses them in the context of current concepts for ophthalmological therapy.

CHEMICAL OCULAR INJURY BY POTASSIUM PERMANGANATE

Abstract Introduction & Objectives : Chemical ocular injury is an emergency case and commonly occured among children. Alkaline chemical ocular injury is more destructive especially due to saponification. One of the rare chemical ocular injury is alkaline trauma by Potassium Permanganate (KMNO4) Methods : A case of a three-year-old boy patient brought by his mother in emergency department at Cicendo Eye Hospital with severe pain, redness, and swelling of the left eye. Ten hours earlier, the patient was playing and accidentally exposed to KMNO4. Visual acuity of the right eye was 6/6 and the left eye was difficult to examine. Ophthalmological examination revealed superior and inferior palpebra are swelling, KMNO4 adhered tightly on conjunctival tarsal superior, inferior, and conjunctival bulbi inferior until fornix and temporal area. Cornea was hazed and iris shadow test positive so he was diagnosed with Chemical Trauma Ropper Hall grade II OS. Treatment begins with irrigation 2 litres of normal saline until pH 7 along with debridement of KMNO4 from conjunctival tarsal superior inferior and bulbi. The patient underwent installation of transplanted amniotic membrane and debridement under anasthesia Results : Management in the initial phase is irrigation. The definitive therapy requires surgery to speed up the healing process. Complications that often occur are corneal limbal cell deficiency, dry eye, symblepharon formation, secondary glaucoma, and complicated cataracts Conclusion : Alkali chemical injury is hazardous and can lead to severe vision threatening complications because of saponification. Prompt and aggressive management is required in such cases to give them the best chance of a more favourable outcome

CHEMICAL OCULAR INJURY BY POTASS CHEMICAL OCULAR INJURY BY POTASSIUM PERMANGANAT

Introduction: Chemical ocular injury is an emergency case and commonly occured among children. Alkaline chemical ocular injury is more destructive especially due to saponification. One of the rare chemical ocular injury is alkaline trauma by Potassium Permanganate (KMNO4). 
 
 Case Report: A case of a three-year-old boy patient brought by his mother in emergency department at Cicendo Eye Hospital with severe pain, redness, and swelling of the left eye. Ten hours earlier, the patient was playing and accidentally exposed to KMNO4. Visual acuity of the right eye was 6/6 and the left eye was difficult to examine. Ophthalmological examination revealed superior and inferior palpebra are swelling, KMNO4 adhered tightly on conjunctival tarsal superior, inferior, and conjunctival bulbi inferior until fornix and temporal area. Cornea was hazed and iris shadow test positive so he was diagnosed with Chemical Trauma Ropper Hall grade II OS. Treatment begins with irrigation 2 litres of normal saline until pH 7 along with debridement of KMNO4 from conjunctival tarsal superior inferior and bulbi. The patient underwent installation of transplanted amniotic membrane and debridement under anasthesia.
 
 Discussion: Management in the initial phase is irrigation. The definitive therapy requires surgery to speed up the healing process. Complications that often occur are corneal limbal cell deficiency, dry eye, symblepharon formation, secondary glaucoma, and complicated cataracts. 
 .
 Conclusion: Alkali chemical injury is hazardous and can lead to severe vision threatening complications because of saponification. Prompt and aggressive management is required in such cases to give them the best chance of a more favourable outcome. 
 
 Keywords: Chemical ocular injury, Potassium permanganate, Chemical burns, Eye trauma

Severity Classification of Limbal Stem Cell Failure Due to Steven Johnson Syndrome in the Light of the Classification Consensus of Limbal Stem Cell Deficiency.

To examine and to understand the limbal stem-cell deficiency (LSCD) because of Steven-Johnson syndrome (SJS) in line with the new classification system for the first time in the literature. Medical records of patients with LSCD because of SJS were reviewed retrospectively. In addition to demographic data and ophthalmologic or systemic findings, anterior segment photographs of the patients were reviewed retrospectively. Limbal stem-cell deficiency severity was graded according to the classification published by the Limbal Stem Cell Working Group. Twenty-four eyes of 14 patients with eye involvement secondary to SJS were included in the study. The mean age of the patients was 36.09±16.70 (9-58) years and the female-to-male ratio was 11:3. The anterior segment photographs of the patients were evaluated by two independent masked observers. Limbal stem-cell deficiency severity was graded according to the classification published by Deng et al. Corneal opacity was divided into three stages according to the area of involvement. Corneal opacity was classified as Stage I if the central 5 mm region of the cornea was not affected, as Stage II if the central 5 mm region of the cornea was affected, and as Stage III if the entire corneal surface was affected. Limbal involvement was classified as Stage A if it was below 50%, as Stage B if it was between 50% and 100%, and as Stage C if it was 100%. This is the first study in the literature to describe and classify LSCD because of SJS, according to the new LSCD classification. Consistent with the results, LSCD follows a bimodal distribution. Most patients demonstrated severe (Stage III-32.14%) or mild (Stage IA-21.42%) LSCD.

Ocular surface inflammation in congenital eye diseases

Ocular surface in children present specificities especially for paediatric diseases. Anterior segment dysgenesia and congenital panocular diseases affect ocular surface. The ocular surface may present congenital opacities as in congenital glaucoma or Peters anomaly. In other diseases as aniridia, limbal insufficiency is evolutive with age creating Aniridia Associative Keratopathy (AAK). The interest of deep phenotyping with molecular genetics opens a wide range of better understanding of congenital ocular diseases. Mechanisms and physiopathology of induced inflammation will be developed.

Update in gene therapies or innovative therapies in aniridia associated keratopathy

Ocular surface may be affected by various rare congenital diseases. Anterior segment dysgenesia and congenital panocular diseases affecting ocular surface is usually from genetic origin. The ocular surface in aniridia may present progressive opacities due to limbal insufficiency creating Aniridia Associative Keratopathy (AAK). Molecular genetics usually reveals PAX6 gene mutation or deletion. Gene therapies in eyedrop form and repurposing drugs are tested for their efficacy and safety in congenital aniridia. Mechanisms and physiopathology of new gene therapies and drugs will be developed.

Long-Term Effects of Adipose-Derived Stem Cells for the Treatment of Bilateral Limbal Stem Cell Deficiency

Purpose To determine the safety and feasibility of human autologous adipose tissue-derived adult mesenchymal stem cells (ASCs) for ocular surface regeneration in patients with bilateral limbal stem-cell deficiency (LSCD). Methods A phase IIa clinical trial was designed (https://Clinicaltrials.gov, NCT01808378) with 8 patients, 3 of whom had aniridia, 2 meibomian glands diseases, 2 multiple surgeries and 1 chronic chemical injury. The therapeutic protocol was as follows: 6-mm of central corneal epithelium was removed, 400,000 ASCs were injected into each limboconjunctival quadrant, 400,000 ASCs were suspended over the cornea for 20 min, and finally the cornea was covered with an amniotic membrane patch. Results No adverse events were detected after a mean of 86,5 months of follow-up. One year after surgery, 6 of the 8 transplants were scored as successful, five patients had improved uncorrected visual acuity (mean of 12 letters), two patients presented epithelial defects (also present at baseline) and the mean percentage of corneal neovascularization was of 28.75% (36.98%, at baseline). Re-examination 24 months after treatment disclosed preserved efficacy in 4 patients. At the last visit (after a mean of 86,5 months of follow up) epithelial defects were absent in all patients although improvement in all of the variables was only maintained in patient 3 (meibomian glands agenesia). Conclusion ASCs are a feasible and conservative therapy for treating bilateral LSCD. The therapeutic effect differs between etiologies and diminishes over time.

Limbal Epithelial Stem Cells Transplantation in Cases with Unilateral Limbal Stem Cell Deficiency Syndrome

This review presents well-known surgical techniques aimed at the treatment of unilateral limbal insufficiency syndrome. Among the many available techniques, one should especially highlight the so-called “simple limbal epithelial transplantation”, which has proven to be an effective, safe and generally available method of treating unilateral limbal insufficiency syndrome (SLN). It should be noted that the risks of recurrence of SLN remain significant, and the mechanisms of engraftment of transplanted limbal epithelial stem cells on the recipient’s eye are not fully understood. The review also considers options for new promising approaches to the possible solution of existing problems in the transplantation of limbal epithelial stem cells.

Optimal fixation period of a combined bioconstruction with buccal epithelial cells in limbal cell deficiency in experiment

BACKGROUND: The search for an effective method for the treatment of limbal stem cell deficiency of various etiologies, leading to intense clouding and vascularization of the cornea, followed by a significant decrease in visual acuity, remains an important and relevant topic in ophthalmology. The results of the studies showed that transplantation of buccal epithelial cells could significantly improve the prognosis of treatment in this category of patients.
 AIM: To determine the optimal fixation period of a combined bioconstruction with buccal epithelial cells for the treatment of limbal cell deficiency in experiment.
 MATERIALS AND METHODS: At the first stage, the corneal epithelium was removed with a scraper in the eyes of experimental animals (12 eyes), and the limb was excised along the entire circumference. Next, to isolate epithelial buccal cells and manufacture a combined bioconstruction consisting of buccal cells, a collagen carrier and a soft contact lens, a flap of the mucous membrane of 5 5 mm was taken from the cheeks of rabbits. At the second stage, after the formation of a fibrovascular pannus on the cornea, it was excised to transparent layers of the cornea, a combined bioconstruction was placed on top. Further, one U-shaped suture was applied at the border of the inner and outer third of the eyelids. Temporary blepharorraphia persisted for 3 days (6 eyes) and 5 days (6 eyes), after the specified time, stitches were removed from the eyelids, and bioconstructions were removed. The bioconstructions removed from the eyes were stained with a vital (lifetime) fluorochrome dye based on tripaflavin and acridine orange, followed by analysis in a fluorescent microscope. The structure of cell nuclei, the overall integrity of the cytoplasm, and the presence of secretory vesicles were evaluated. After 7 and 14 days after transplantation of the bioconstruction, the area of erosion, the extent of new vessels and the transparency of the cornea were evaluated. When the observation was completed, the rabbits were removed from the experiment, and the eyes were enucleated and subjected to histological examination.
 RESULTS: On the surface of all bioconstructions removed after 5 days, only leukocytes were detected. At the same time, on collagen matrix of bioconstructions removed after 3 days, in addition to leukocytes, there were also buccal epithelial cells with normal nuclear structure and chromatin topography in its composition, as well as with secretory vesicles. On days 714, both groups showed a decrease in the area of erosion, while the dynamics of ocular surface recovery processes was more pronounced in the group with fixation of the bioconstruction for 5 days.
 CONCLUSIONS: According to the results of in vivo staining with fluorochrome dye of combined bioconstructions removed from the cornea of experimental animals 3 and 5 days after superficial keratectomy, as well as the data of clinical and histological examination, the optimal period for bioconstruction fixation was established to be 5 days.

Ocular-Surface Regeneration Therapies for Eye Disorders: The State of the Art

The ocular surface is a complex structure that includes cornea, conjunctiva, limbus, and tear film, and is critical for maintaining visual function. When the ocular-surface integrity is altered by a disease, conventional therapies usually rely on topical drops or tissue replacement with more invasive procedures, such as corneal transplants. However, in the last years, regeneration therapies have emerged as a promising approach to repair the damaged ocular surface by stimulating cell proliferation and restoring the eye homeostasis and function. This article reviews the different strategies employed in ocular-surface regeneration, including cell-based therapies, growth-factor-based therapies, and tissue-engineering approaches. Dry eye and neurotrophic keratopathy diseases can be treated with nerve-growth factors to stimulate the limbal stem-cell proliferation and the corneal nerve regeneration, whereas conjunctival autograft or amniotic membrane are used in subjects with corneal limbus dysfunction, such as limbal stem-cell deficiency or pterygium. Further, new therapies are available for patients with corneal endothelium diseases to promote the expansion and migration of cells without the need of corneal keratoplasty. Finally, gene therapy is a promising new frontier of regeneration medicine that can modify the gene expression and, potentially, restore the corneal transparency by reducing fibrosis and neovascularization, as well as by stimulating stem-cell proliferation and tissue regeneration.

Сравнительное экспериментальное исследование прозрачности, механических свойств и биодеградации синтетических полимерных матриц как возможных носителей для культивируемых лимбальных эпителиальных стволовых клеток

Purpose. To investigate the transparency, mechanical properties and terms of biodegradation of certain types of synthetic polyester matrices – poly(lactide-glycolide) (PLG), poly(lactide-caprolactone) (PLC) and poly(ε-caprolactone) (PCL) as possible carriers for cultured limbal epithelial stem cells. Material and methods. In the course of the study, the transparency of all polyester matrices of various thicknesses was evaluated by the width of the scattering angle of a helium-neon laser beam with a wavelength of 632.8 nm. The mechanical properties of the matrices (only 5 microns thick) and amniotic membrane (AM) (strength, elongation at break, modulus of elasticity) were studied under their uniaxial tension on a universal installation. Biodegradation was evaluated for all matrices from PLG, PLC and PCL – on 18 rabbits (12 eyes). The matrices were transplanted and sewn onto intact corneas. The biodegradation of the matrices was evaluated on the 3rd, 10th, 21st and 30th days after surgery. Results. The optical and mechanical properties of matrices made of polylactide-glycolide (PLG), polylactide-caprolactone (PLC) and poly(ε-caprolactone) (PCL) were studied during the study. The terms of biodegradation of matrices from PLC with a thickness of 5 microns were about 30 days. Conclusion. Taking into account the optimal combination of strength, elasticity, elasticity and transparency, the most acceptable for use as a carrier for transplantation of cultured LESC in order to eliminate limbal insufficiency is a matrix of PLC with a thickness of 5 microns. Keywords: transparency, mechanical properties, biodegradation, polymer matrices

Ocular-periocular burns in a tertiary hospital: Epidemiologic characteristics

Ocular burns are ophthalmic emergencies that can cause devastating injuries. This study aimed to analyze the epidemiology, complications, and management of ocular-periocular burns. A total of 193 patients with ocular-periocular burns were admitted to our tertiary hospital from January 2018 to December 2020. The demographic characteristics of the patients, injury variables, complications, and treatments were evaluated. There were 142 male (73.6%) and 51 female (26.4%) patients with a mean age of 32.53±17.75 years. The average total body surface area was 12% (range, 1-80%). Injuries were most common at work (52.3%) and home (36.3%). Thermal burns were the most common injuries (74.6%), followed by chemical (14.5%) and electrical burns (10.9%). Alkaline agents (75.0%), mainly sodium hydroxide and lime, were common in chemical burns. Superficial lid burns were significantly higher in the thermal group (p<0.001), and grade III-IV corneal burns were significantly higher in the chemical group (p<0.001). Various complications were developed in 50 (13%) eyes. Medical treatment only was performed in 318 (82.4%) eyes, and additional surgical treatment was performed in 64 (17.6%) eyes; however, 54 (14.0%) underwent more than one surgery. The most common complications were corneal scars (7.3%), limbal deficiency (4.1%), and ectropion (3.9%). The most frequent procedures performed were amniotic membrane transplantation (AMT) (11.9%) and tarsorrhaphy (6.7%). Chemical burns, limbal and conjunctival ischemia, and full-thickness eyelid defects had a poor prognosis. The degree of limbal deficiency and ınjury of intraocular structures were found to have a great influence on the outcome of their visual acuity.

Plasticity of ocular surface epithelia: Using a murine model of limbal stem cell deficiency to delineate metaplasia and transdifferentiation.

Maintaining corneal health and transparency are necessary pre-requisites for exquisite vision, a function ascribed to stem cells (SCs) nestled within the limbus. Perturbations to this site or depletion of its SCs results in limbal SC deficiency. While characterizing a murine model of this disease, we discovered unusual transformation phenomena on the corneal surface including goblet cell metaplasia (GCM), conjunctival transdifferentiation, and squamous metaplasia (SQM). GCM arose from K8+ differentiated conjunctival epithelial cells when the limbus was breached and was exacerbated by neovascularization. Regions within the cornea that harbored newly transformed K12+ epithelia were void of blood vessels and GCs, suggesting that the cornea also initiated a self-repair program. Knowledge of the intrinsic circuits that contribute to cell identity change in lineage-restricted epithelia will be invaluable for designing new therapeutics for patients with blinding corneal disease.

Экспериментальное исследование возможности использования синтетических материалов для создания матриц-носителей стволовых клеток с целью применения в хирургии роговицы

Purpose. Тo study in the experiment the properties of three different types of synthetic polyester matrices, to conduct their comparative assessment and determine the optimum as a carrier for the cultivation and transplantation of limbal stem cells while eliminating limbal insufficiency. Material and methods. Тransparency, mechanical properties, biocompatibility with cell cultures of the cornea, as well as the study of the timing of matrix biodegradation in vivo were carried out. Results. Тhe study examined the optical and mechanical properties of matrices made from polylactide-glycolide (PLG), polylactide-caprolactone (PLC) and poly-ε-caprolactone (PCL). It was experimentally shown that human and rabbit limbal stem cells, as well as human corneal epithelium cells, adhered on the surface of all types of matrices under investigation, and during cultivation they retained the typical structure of actin cytoskeleton, the ability to proliferate and migrate. Differences in the interaction of different cell cultures with different types of carriers were revealed. The terms of biodegradation of PLC matrices with a thickness of 5 μm was about 30 days. Conclusion. Тhe results indicate that it is possible to use 5 μm thick PLC matrices as a carrier of cultured limbal stem cells. Keywords: poly (lactide-glycolide), poly (lactide-caprolactone), poly (ε-caprolactone), biodegradation, limbal stem cells.

Pediatric Phlyctenular Keratoconjunctivitis at a Tertiary Care Center in the United States.

The aim of this study was to evaluate characteristics and outcomes of pediatric phlyctenulosis at a tertiary care center in the United States. A retrospective cohort study of phlyctenulosis diagnosis in patients younger than 18 years was conducted. Demographics, presenting features, treatment regimens, and outcomes were analyzed. Seventy patients (95 eyes) with phlyctenulosis were identified. Fifty-four patients (77.1%) were Hispanic, which was greater than the center's proportion of pediatric patients identifying as Hispanic (53.8%, P < 0.0001). Common comorbidities included adjacent external/lid disease (82.9%), allergic/atopic disease (18.6%), and viral infections (8.6%). Nine patients had tuberculosis testing which was negative in all cases. Five patients had vitamin A testing which revealed deficiency in 1 patient. Treatment regimens were diverse and included varying combinations of topical and systemic medications. Complications included corneal scarring (27.4%), corneal neovascularization (40.0%), amblyopia (16.8%), corneal perforation (3.2%), and severe limbal stem-cell deficiency (1.1%). 26.3% of affected eyes had final visual acuity worse than 20/40. Differences in rates of corneal complications between Hispanic and non-Hispanic patients were not statistically significant, although severe corneal complications including perforation occurred only in the Hispanic group. This study presents a modern cohort of phlyctenulosis at a tertiary center in the United States and includes a larger proportion of Hispanic patients than expected. Phlyctenulosis carries high corneal morbidity and may frequently result in reduced visual acuity. Similar rates of corneal complications were seen in Hispanic versus non-Hispanic patients, but severe corneal complications were seen only in the Hispanic group.

Clinical Characteristics and Severity Distribution of Tertiary Eye Center Attendance by Ocular Chemical Injury Patients.

To report demographic characteristics, types and grades of injury, regional distribution of injury severity, clinical findings, and long-term results of acute ocular chemical burns. Medical records of patients with chemical burns between 2010 and 2020 who were admitted to Ege University less than 72 hr after the injury were reviewed. Age, gender, cause of the burn, injury severity, initial and final best-corrected visual acuity, surgical intervention, and complications were recorded. The injury severity was graded according to Dua classification. A total of 104 patients (137 eyes) were included. The mean age was 42.69±17.39 (7-90) years with a male-to-female ratio of 86:18. The most common causes were home (32.6%) and industrial accidents (45.1%). The causative agent percentages for alkaline, acid, and neutral were 49.0%, 35.5%, and 5.7%, respectively. The percentages of eyes in each grade (1-6) were 16.0%, 16.0%, 15.3%, 16.7%, 17.5%, and 18.2%, respectively. Complications mostly occurred in eyes with grade 2 or higher injuries (83.7%). The relationship between injury grade and limbal stem-cell deficiency was statistically significant (P<0.001). Surgery was mostly needed in grade 4 or higher injuries (44 eyes). The severity of the burn is one of the most important prognostic factors in chemical burns. It is important to determine the spreading of the regional injury severity beside the global one to predict complication risk of the injuries. In the present study, the injury distribution was homogeneous in all grades. Limbal stem-cell deficiency development took place mostly in grade 5 and 6 burns as expected.

Persistent Epithelial Defects Caused by Limbal Deficiency for Various Causes

Purpose: We report the process of treating persistent corneal epithelial defects due to limbal deficiency in a patient who underwent surgery for ptosis, recurrent pterygium, and senile cataract for 3 weeks.Case summary: A 65‐year‐old male patient underwent cataract surgery 4 months ago and visited this hospital with persistent inflammation of the left cornea that started 2 months ago. The patient underwent blepharoplasty and pterygium surgery at the same time 3 weeks before cataract surgery. At the first visit, severe conjunctival injection and an oval‐shaped corneal epithelial defect with a size of 3 × 5 mm in the center of the cornea were seen. As the result of the eyelid eversion test, fibrotic scar tissue due to the non‐absorbable suture used during the upper eyelid blepharoplasty was observed and surgically removed. The corneal epithelial defect site became smaller, but the atrophy of the corneal stroma was sustained, and the amniotic membrane was tripled and permanent amniotic membrane transplantation was performed. Corneal epithelial defects have improved with postoperative best‐corrected visual acuity of 0.15.Conclusions: Sufficient recovery period between serial multiple surgeries is required to reduce the occurrence of complications like persistent epithelial defects.

Transplantation of cells of the oral mucosa in the treatment of limbal stem cell deficiency

The actual problem of treatment of patients with limbal cell stem deficiency is reviewed. We summarized practical experience in various fields of medicine, aimed at tissue reconstruction using cells of the buccal mucosa. In ophthalmology, an effective method has long been searched to treat patients with the limbal stem cell deficiency causing an intense opacification and vascularization of the cornea and followed by a significant decrease in visual acuity. Recent studies have shown that the transplantation of epithelial cells of oral mucosa can significantly improve the treatment of patients with this disease. Although the mechanisms of oral mucosa epithelial cells' action are still insufficiently studied, the existing positive experience of oral mucosa using for tissue repair has great interest to practitioners, giving potential possibilities of its use, therapeutic effectiveness and ease of obtaining. A brief review of the literature presents the description of the morphological features of the. buccal mucosa and the analysis of published data about the use of buccal epithelium in various branches of medicine and in ophthalmology, in particular.

Experience of using a thrombofibrin clot of plateletrich plasma in ulcerative lesions of the cornea

Purpose: to study the effectiveness of the use of thrombofibrin clot of platelet-rich plasma (PRP) in patients with corneal ulcers. Material and methods. A clinical study, conducted by the Department of Traumatology and Reconstructive Surgery of Helmholtz National Medical Research Center of Eye Diseases, involved 20 patients, aged from 22 to 82, with corneal ulcers of inflammatory and burn genesis more than 100 microns deep. All patients got coated with a thrombofibrin PRP clot from autologous blood. Prior to the study, all patients received standard treatment for 2 weeks to 3 months, including multiple amniotic membrane coating, with no effect. The thrombofibrin clot was produced by the Scientific Department of Biotechnology and Transfusiology of the N.V. Sklifosovsky Research Institute for Emergency Medicine. The ready clot was placed on the surface of the cornea and covered with an amniotic membrane. The membrane was fixed to the episclera along the border of the limb with a circular suture, whereupon autologous serum was injected along the limb in 4 quadrants, to be followed by temporary lateral blepharography. Results. On the 2nd day following the procedure, the patients noted a decrease in lacrimation and pain in the operated eye. As shown by optical coherence tomography, the average depth of the corneal ulcer at the beginning of the study in all patients was 129 ± 28.5 microns. On the 5th day, the depth lowered to an average of 71 ± 32.6 microns, and on the 10th day, to 23.3 ± 15.1 microns. In 7 patients (35%), complete healing of the defect was observed on the 15th day, while in 9 patients (45%) it was stated between the 16th and the 20th day. Thus, the average time of healing of the ulcer with complete epithelization occurred was 15 days. In four patients with the consequences of severe burns (20%), the ulcer did not heal due to extensive damage to the limbal zone. Conclusion. The use of a thrombofibrin PRP clot in combination with amniotic membrane transplantation allows achieving a stable and fairly rapid healing of corneal ulcers of various origins. However, this method is ineffective in patients with limbal cell insufficiency, severe burns and extensive damage to the limbal zone. In such cases, it is advisable to use more radical surgical methods, such as buccal or limbal cell transplantation, or allolimbal transplantation.