Minor ipsilateral simple limbal epithelial transplantation (mini-SLET) for pterygium treatment

[Modified mini-SLET for treatment of complex cases in pterygium surgery]

BACKGROUND

The major problem associated with the benign but destructive growing pterygium is the high recurrence rate. A new surgical technique to lower recurrence rates is minor ipsilateral simple limbal epithelial transplantation (mini-SLET), where the regeneration potential of limbal stem cells is used in combination with amniotic membrane transplantation (AMT) for surgical reconstruction. The aim of this study is to assess the surgical outcome of the mini-SLET technique with tenonectomy, mitomycin C, and AMT as used in the authors' hospital.

MATERIALS AND METHODS

A total of 16 eyes from 15 patients undergoing mini-SLET after surgical pterygium removal with tenonectomy, mitomycin C, and AMT were analyzed retrospectively. Two different groups of pterygia were enrolled: group 1 included recurrent pterygia (n = 10) and group 2 comprised primary large pterygia such as double-head pterygia (n = 6). In addition to assessment of best corrected visual acuity and compete ophthalmological examination, preoperative slip-lamp examination with photo documentation served to calculate the corneal size of the pterygium head using VISUPAC software (Zeiss, Oberkochen, Germany). Postoperatively, best corrected visual acuity and slit-lamp examination were routinely evaluated. The surgical outcome was defined by the postoperatively achieved best corrected visual acuity, restoration of the ocular surface, recurrence rate, and rate of postoperative complications.

RESULTS

Median follow-up in all patients was 27 months; in groups 1 and 2 it was 30.7 and 25.3 months, respectively. No recurrence developed in 15 eyes (93.75%). Only one group 1 patient (6.25%) suffered a recurrent lesion after 10 months. Postoperatively, logMAR visual acuity did not change significantly. During follow-up, complications were limited to one case of early wound dehiscence.

CONCLUSION

Mini-SLET in combination with tenonectomy, mitomycin C, and AMT enables good surgical reconstruction of the ocular surface, and almost complete healing in the sense of restitutio ad integrum is possible. The results of the present study have shown the technique's effectiveness for recurrence prevention.

Comparison of mini-simple limbal epithelial transplantation and conjunctival-limbal autograft for the treatment of primary pterygium: a randomised controlled trial

PURPOSE

The purpose of this double-masked, parallel randomised controlled trial was to compare the recurrence rate and other outcomes between conjunctival-limbal autograft (CLAu) and mini-simple limbal epithelial transplantation (mini-SLET) after excision of pterygium.

METHODS

Eligibility criteria for participants was the presence of a primary nasal pterygium extending equally to or greater than two millimetres on the cornea on its horizontal axis from the nasal limbus. The participants were allocated into two groups (CLAu and mini-SLET) using simple randomisation with a table of random numbers. Participants and the outcome assessor were masked to the intervention. The study protocol is listed and available on https://clinicaltrials.gov (Identifier: NCT03363282).

RESULTS

A total of 61 eyes were enrolled in the study, 33 underwent CLAu (group 1) and 28 mini-SLET (group 2), all eyes were analysed in each group. At 2, 3, 6 and 12 months the CLAu group exhibited a recurrence of 0%, 6.1%, 8.1% and 8.1%, while the mini-SLET exhibited a recurrence of 0%, 17.9%, 50% and 53.5% (p<0.05). There were no intraoperative or postoperative complications in either of the two groups.

CONCLUSION

The findings of this study suggest that mini-SLET has a higher recurrence rate and provides no advantage over CLAu in the treatment of primary pterygium.

The immunology of corneal limbal stem cells: the up-to-date approach to stem cell transplantation

Limbal epithelial stem cells (LSC, LESC) are multipotent cells used as regenerative treatment of the cornea in patients with limbal epithelial stem cell deficiency (LSCD, LESCD). There are different types of stem cell grafting including cultivated limbal epithelial transplantation (CET) and simple limbal epithelial transplantation (SLET). The outcomes of the techniques have been assessed as similar, with differences in the sample size required during the procedures. The most important culture components for stem cell cultivation include 3T3 murine fibroblasts, human amniotic membrane (HAM), fibrin gel, and culture medium. The culture medium may be enriched with serum or not; however, xenobiotic-free materials are preferred because of the low risk of pathogen transmission. Multiple studies have defined molecules important for maintaining the function of LSC including C/EBP δ, Bmi-1, p63 α, interleukins (IL-6), epithelial structural proteins - keratins, and antibodies against epidermal growth factor receptor (EGFR). The cell phenotype of LSC has been described with factors of transplantation success rate such as a high percentage of p63 positive cells. The article emphasizes the role of recipient tissue preparation, modern cultivation techniques and pathophysiological processes in LSC transplantation effectiveness.

Modified Supportive Simple Limbal Epithelial Transplantation (M-SLET): A surgical technique modified for limbal stem cell deficiency

This study aimed to develop and modify the surgical technique of simple limbal epithelial transplantation in patients with limbal stem cell deficiency to provide support to epithelial explants during the post-operative period. This is a case series of five eyes of five patients who underwent modified supportive simple limbal epithelial transplantation (M-SLET) surgery. The health and stability of the ocular surface were assessed based on clinical slit lamp examination; they were the main outcome measures. All patients had a stable ocular surface and healed epithelium during all the follow-up visits. The M-SLET technique provides additional support to limbal epithelial explants, adhering to the cornea, thus creating a stable epithelial surface. This is particularly important when there is a risk of explants being dislodged by eye rubbing.

Autologous simple conjunctival epithelial transplantation for primary pterygium

PURPOSE

To evaluate the feasibility of a new method of conjunctival transplantation to achieve recovery of the normal conjunctival epithelium over the bare sclera after pterygium excision and prevent its recurrence.

METHODS

After excision of the primary pterygium, we performed simple conjunctival epithelial transplantation (SCET) in which we glued an amniotic membrane patch pre-loaded with tiny autologous conjunctival tissue fragments over the scleral defect. Slit-lamp evaluation was performed at 2 and 7-10 days, and then at 1, 3, 6, and 12 months after surgery, together with confocal microscopy at 3, 6, and 12 months.

RESULTS

Surgical excision and SCET for nasal primary pterygium were performed in 6 eyes (6 patients). No graft detachment occurred. An inflammatory granuloma was excised without sequelae in one patient 2 months after surgery. No signs of recurrence or sight-threatening complications were recorded at 12 months, and in vivo confocal microscopy showed progressive expansion of the conjunctival cell population and formation of a clear corneal-conjunctival transition.

CONCLUSIONS

SCET takes advantage of the ability of the amniotic membrane and conjunctival cells to renew. Outcomes after SCET are comparable to conventional conjunctival flap surgery and can be achieved in less surgical time and with less donor tissue to be removed.

Case Report: Allogenic Simple Limbal Epithelial Transplantation From a Human Leukocyte Antigen-Matched Living Related Donor to Treat Bilateral Corneal Chemical Burns Post Laser-Assisted in situ Keratomileusis

A 35-year-old woman who had undergone laser-assisted in situ keratomileusis in both eyes experienced bilateral total limbal stem cell deficiency (LSCD) due to chemical burns. Due to bilateral severe LSCD, allogenic simple limbal epithelial transplantation (SLET) from a human leukocyte antigen (HLA)-matched living related donor was the first choice of treatment for her left eye. We report the first case of HLA or ABO matching living related allogenic SLET for permanent restoration of the cornea for bilateral LSCD treatment. Our ABO-HLA-matched living related allogenic SLET alleviation of the systemic immunosuppressant to topical corticosteroids alone. It also came the limitations of prolonged systemic immunosuppressant usage in conjunctival-limbal allografts and keratolimbal allograft.

Conjunctival Autograft versus Combined Amniotic Membrane and Mini-Simple Limbal Epithelial Transplant for Primary Pterygium Excision

Purpose

To compare outcomes of conjunctival autograft (CAG) and combined amniotic membrane with mini-simple limbal epithelial transplant (mini-SLET) after primary pterygium excision.

Methods

All consenting adults with primary pterygium were included in this study. After pterygium excision, patients were randomized to receive either CAG or mini-SLET and both grafts were held in place with fibrin glue. The patients were followed-up at days 1, 3, 7, 14, and 30 and subsequently at the third, sixth, and ninth months. The recurrence rate was considered as the primary outcome measure whereas the operating time, postoperative symptoms, and surgical complications were considered the secondary outcome measures.

Results

The study comprised of 264 eyes of 264 patients, of which 233 (88%) completed the nine months of follow-up. Of these, 118 (51%) received CAG and 115 (49%) received mini-SLET. The groups were comparable at baseline. Recurrence of pterygium was seen in two (1.6%) eyes in the CAG group and three (2.6%) eyes in the mini-SLET group (P = 0.68). Operative time for mini-SLET (20.33 ± 1.28 min) was significantly higher than that for CAG (12.01 ± 1.26 min) (P < 0.001). Graft displacement was observed in one case in group II (P = 0.999). The Lim Bon Siong (foreign body sensation, lacrimation, pain, and irritation) score in the CAG group was statistically significant for all four symptoms at days 1 and 3; however, at day 7, foreign body sensation, pain, and irritation scores were significantly higher for the CAG group.

Conclusion

In this study, the overall recurrence rate was very low and comparable between mini-SLET and the established technique of CAG after performing the primary pterygium excision. Despite a longer surgical time, mini-SLET appears to be a viable option for the management of primary pterygium.

Outcomes of Ipsilateral Simple Limbal Epithelial Transplantation, Tenonectomy, Mitomycin and Amniotic Membrane Transplantation for Treatment of Recurrent Pterygium

PURPOSE

To report on the outcomes of recurrent pterygium treated by ipsilateral simple limbal epithelial transplantation (SLET), mitomycin, tenonectomy, and amniotic membrane transplantation.

METHODS

A retrospective, interventional study was conducted including all patients with recurrent pterygium who underwent SLET surgery under a single surgeon using ipsilateral donor tissue with a minimum 6-month follow-up at Toronto Western Hospital, Canada. Outcome measures included the following: recurrence rates, best spectacle-corrected visual acuity, and postoperative complications.

RESULTS

Ten eyes of 10 patients, aged 60.7 ± 18.5 years (range 23-79) with a mean follow-up time of 15.2 ± 10.0 months of which 50% (n = 5) were men, were included. Eight eyes (80%) had a history of 2 or less pterygium operations. Two patients had 3 and 5 previous pterygium operations, respectively. Concurrent limbal stem cell disease was noted in 6 eyes (60%). Average number of pterygium recurrences per eye was 1.9 ± 1.3 (range 1-5). Mean pre-op best-corrected visual acuity was 0.5 LogMAR (Snellen equivalent 20/60, range 20/20 to counting fingers). Best-corrected visual acuity remained the same or improved in 6 eyes (60%). Recurrence was noted in 1 eye (10%) with a history of 5 previous pterygium excisions and remained stable at the last follow-up. No patients required a second operation.

CONCLUSIONS

Ipsilateral SLET with mitomycin, tenonectomy, and amniotic membrane transplantation is a novel technique to address recurrent pterygium. Concurrent limbal stem cell diseases are often present. Initial results demonstrate low recurrence. Visual improvement is modest. Stabilization of the ocular surface to improve vision is possible.

Innovative technique of mini-simple limbal epithelial transplantation in pediatric patients

In this article, we introduce a modified technique of minor ipsilateral simple limbal epithelial transplantation (mini-SLET) in pediatric patients of limbal stem cell deficiency (LSCD). Two children with unilateral partial LSCD underwent the innovative technique of mini-SLET, where harvested limbal tissues were placed over the raw cornea and were covered with amniotic membrane. Both patients were followed till 9 months. Both cases showed favorable outcome and uneventful recovery. Results were comparable with the classical technique. This innovative modification of mini-SLET is safe, feasible, and an effective alternative with favorable visual outcome especially in pediatric population. It can be a breakthrough for LSCD management in developing countries with limited resources.

Efficacy and outcome of simple limbal epithelial transplantation for limbal stem cell deficiency verified by epithelial phenotypes integrated with clinical evaluation

PURPOSE

To evaluate the efficacy and outcome of simple limbal epithelial transplantation (SLET) for limbal stem cell deficiency (LSCD) using epithelial phenotype detection integrated with clinical manifestation.

METHODS

This prospective multicenter study included patients with LSCD who underwent autologous SLET (autoSLET) and living-related allogenic SLET (Lr-alloSLET). All patients were assessed by slit-lamp biomicroscopy, in vivo confocal microscopy (IVCM), and impression cytology with immunofluorescence staining (ICIF) before and after surgery. The criteria for success were the presence of a clinically non-conjunctivalized cornea and corneal epithelium detected by IVCM or ICIF. Otherwise, the case would be considered a failure. Visual improvement and risk factors for SLET failure were analyzed.

RESULTS

A total of 28 eyes of 26 patients (11 autoSLET and 17 Lr-alloSLET) were included. The median age was 53 years (range, 35-63), and the follow-up time was 29.5 months (range, 17.5-39.8). The overall survival rate was 89.3% at 2 years and 75.6% at 3 years with no difference between autoSLET and Lr-alloSLET (p = 0.24). Seven eyes subsequently underwent penetrating keratoplasty. Immunohistochemistry analysis showed that all corneal buttons had corneal epithelium and limbal stem cell markers. Visual improvement was achieved in both SLET groups (p < 0.001). Failed SLET developed between 5 and 32 months postoperatively. However, absolute risk factors for SLET failure were unidentified.

CONCLUSION

The efficacy of autoSLET and Lr-alloSLET for LSCD was excellent. Limbal explants can regenerate and restore the corneal surface while maintaining the characteristics of limbal stem cells as shown by epithelial phenotype detection and immunohistochemistry integrated with clinical evaluation.

Bibliometric analysis and mapping knowledge domain of pterygium: 2000-2019

AIM

To track the knowledge structure, topics in focus, and trends in emerging research in pterygium in the past 20y.

METHODS

Base on the Web of Science Core Collection (WoSCC), studies related to pterygium in the past 20y from 2000-2019 have been included. With the help of VOSviewer software, a knowledge map was constructed and the distribution of countries, institutions, journals, and authors in the field of pterygium noted. Meanwhile, using co-citation analysis of references and co-occurrence analysis of keywords, we identified basis and hotspots, thereby obtaining an overview of this field.

RESULTS

The search retrieved 1516 publications from WoSCC on pterygium published between 2000 and 2019. In the past two decades, the annual number of publications is on the rise and fluctuated a little. Most productive institutions are from Singapore but the most prolific and active country is the United States. Journal Cornea published the most articles and Coroneo MT contributed the most publications on pterygium. From co-occurrence analysis, the keywords formed 3 clusters: 1) surgical therapeutic techniques and adjuvant of pterygium, 2) occurrence process and pathogenesis of pterygium, and 3) epidemiology, and etiology of pterygium formation. These three clusters were consistent with the clustering in co-citation analysis, in which Cluster 1 contained the most references (74 publications, 47.74%), Cluster 2 contained 53 publications, accounting for 34.19%, and Cluster 3 focused on epidemiology with 18.06% of total 155 co-citation publications.

CONCLUSION

This study demonstrates that the research of pterygium is gradually attracting the attention of scholars and researchers. The interaction between authors, institutions, and countries is lack of. Even though, the research hotspot, distribution, and research status in pterygium in this study could provide valuable information for scholars and researchers.

Mini-Review: Regenerating the Corneal Epithelium With Simple Limbal Epithelial Transplantation

Simple limbal epithelial transplantation (SLET) is an ingenious, low cost and effective technique of limbal stem cell transplantation (LSCT) that is increasingly being undertaken in practice across the world. Since it was first described a decade ago, the technique has been performed in a variety of cases of limbal stem cell deficiency (LSCD) and has underwent several innovative modifications. Published literature on SLET has progressively increased over time and successful outcomes in various clinical scenarios have been reported. This concise review attempts to present a crisp account of SLET covering the indications and contraindications of performing the procedure; detailed account of pre-operative work up and preparation; surgical technique and its modifications; post-operative course, care and possible complications as well as published outcomes of surgery from across the world. Comparative analysis of various techniques of LSCT have been discussed and common concerns of surgeons practising or those who are planning to start practising SLET have been addressed. The authors hope that the pragmatic insights and pearls given at the end of the review will aid the surgeons in performing this technique to provide maximum benefit to patients suffering from the potentially blinding condition of LSCD.

Economic, clinical and social impact of simple limbal epithelial transplantation for limbal stem cell deficiency

Aims

To report the global uptake of simple limbal epithelial transplantation (SLET) and compare the economic, clinical and social outcomes of SLET with those of cultured limbal epithelial transplantation (CLET).

Methods

A comprehensive literature review and an online survey of eye surgeons were conducted to understand the efficacy and current uptake of SLET surgery. A de novo economic model was developed to estimate the cost savings with SLET compared with CLET. Our economic analysis is conducted from an Indian perspective, as this is where the technique originated. A scenario analysis using the UK cost data and a user-friendly Excel model is included to allow users to input the costs from their setting to estimate the cost savings with using SLET compared with using CLET

Results

The anatomical success with SLET in adults (72.6% (range 62%–80%)) was the same as CLET (70.4% (range 68%–80.9%)). For children, the outcome for SLET (77.8% (range 73%–83%)) was better than with CLET (44.5% (range 43%–45%)). In response to our informal questionnaire, 99 surgeons reported to have performed SLET on 1174 patients in total. They appreciated that SLET negates the requirement for costly tissue engineering facilities. Results of economic analysis suggested that SLET provided an estimated cost-savings of US$6470.88 for adults and US$6673.10 for children. In broad terms, the cost of SLET is approximately 10% of the cost of CLET for adults and 8% for children.

Conclusion

SLET offers a more accessible and financially attractive alternative to CLET to treat limbal stem cell deficiency.

Modified head inversion technique for pterygium and pseudopterygium surgery combined with keratopigmentation

PURPOSE

We describe a single sitting modified technique of pterygium surgery along with corneal tattooing for combined cosmetic rehabilitation in eyes with corneal opacity and pterygium or pseudopterygium.

METHOD

Five patients with corneal opacity due to healed keratitis/optically failed therapeutic grafts along with pterygium or pseudopterygium underwent combined pterygium surgery by head inversion technique and corneal tattooing in the same sitting. All patients had no visual prognosis in that eye and surgery was indicated for cosmetic reasons only.

RESULTS

At 6 months follow up no complications of pterygium surgery like recurrence, thinning, dellen, infections were noted in any patient. The dye was retained in the cornea and the cosmetic rehabilitation was excellent in all patients.

DISCUSSION

Corneal tattooing combined with pterygium/pseudopterygium surgery can be performed in a single sitting with this novel technique in eyes with no visual potential. This is particularly suitable for eyes with limbal stem cell deficiency or large pterygia/pseudopterygia where conjunctival autograft is not advisable. These patients are often apprehensive for an allograft from their only seeing other eye.

Comparison and application of commercially available fibrin sealants in ophthalmology

Fibrin glues carry many advantages over traditional suture as a tissue adhesive and have been increasingly used in a variety of ophthalmic procedures over the past 15 years. Several fibrin sealants are commercially available worldwide, each of which differs slightly in its composition and mechanism of delivery. The focus of our review is to briefly discuss the reported uses of fibrin in ophthalmic surgery and provide a broad overview of the properties associated with each commercially available fibrin sealant.

Mini-Simple Limbal Epithelial Transplantation Versus Conjunctival Autograft Fixation With Fibrin Glue After Pterygium Excision: A Randomized Controlled Trial

PURPOSE

To compare the outcomes between mini-simple limbal epithelial transplantation (mini-SLET) and conjunctival autograft (CAG) fixation with fibrin glue after excision of pterygium.

METHODS

Ninety-two eyes with primary nasal pterygium were prospectively randomized into a CAG control arm and a mini-SLET study arm. Follow-up examinations were set at the first and third day, at weeks 1, 2, and 4, and at the third and sixth month after surgery. The primary outcome measure was the recurrence rate at 1, 3, and 6 months after surgery, whereas the secondary outcome measures were the intraoperative time, postoperative symptoms, and other complications.

RESULTS

Eighty-two eyes completed the 6-month follow-up interval. Of the 42 eyes that underwent CAG, 4 (9.5%) exhibited recurrences, whereas only 1 of the 40 eyes (2.5%) treated with mini-SLET had recurrence (P = 0.358). The time taken for surgery in the study group (21.4 minutes) was greater as compared to the control group (15.1 minutes) (P < 0.001). The postoperative median symptom (foreign body sensation, lacrimation, pain, and irritation) score in the CAG group was significantly more for all symptoms on day 1 and day 3; however, on day 7, it was significantly more for pain and irritation only. Except dellen formation (1 in each group), both groups exhibited different other complications, although less in the study group.

CONCLUSIONS

The study group exhibited a positive trend of less recurrence with reduced postoperative symptoms and other complications. More similar studies are required in future to validate the results.

Releasable Suture versus Autologous Blood for Pterygium Surgery using Conjunctival Autografts

Purpose

To evaluate the efficacy of releasable single suture (RS) for conjunctival autograft (CAG) and to compare it with sutureless gluefree (SG) technique in pterygium surgery.

Methods

We conducted a retrospective comparative study on patients with primary pterygium who underwent CAG. In 150 patients, CAG was additionally secured by a single 10-0 nylon releasable suture (RS) which was released on the first postoperative day. In 47 patients, no suture was applied, and CAG was allowed to stick to the scleral bed by autologous fibrin only (SG group). The duration of surgery and size of CAG (in mm 2 ) was noted in both groups. All patients completed one year of follow-up. Factors that were studied included graft stability, patient comfort, complications, and recurrence.

Results

The mean age of patients in RS and SG groups was 39.6 ± 11.8 and 47.3 ± 13.8 years, respectively. The mean duration of surgery was 4.84 ± 1.34 min in RS group and 4.90 ± 1.42 min in SG group (P = 0.001). The size of CAG used in both groups was comparable with more stability in RS group postoperatively. Graft retraction rate in RS group was 5.3% (1 mm retraction in CAG more than 36 mm 2 ) with no event of graft loss. The graft loss occurred in 6.3% of eyes in SG group. The recurrence rate in RS group was 4%, while in SG group it was 6.3% (P = 0.4).

Conclusion

RS, by augmenting the autologous blood mechanism, may offer an easy to learn option for pterygium surgery with good stability even in large sized CAGs.

Simple limbal epithelial transplantation (SLET): Review of indications, surgical technique, mechanism, outcomes, limitations, and impact

Simple limbal epithelial transplantation (SLET) is an innovative limbal stem cell transplantation technique that has gained increasing popularity over the last few years. Different groups from across the world have published the clinical results of SLET in large case series with varying types and severities of limbal stem cell deficiency (LSCD). This review attempts to place all the available knowledge on SLET together in one place for the benefit of not only cornea specialists and trainees but also for residents and general ophthalmologists. It follows a balanced approach of blending evidence with experience by providing an objective analysis of published results along with helpful insights from subject experts, starting from preoperative considerations including the role of newer imaging modalities to the technical aspects of the surgery itself and the management of possible complications. Original data and novel insights on allogeneic SLET for bilateral LSCD are included in the review to address the few remaining lacunae in the existing literature on this topic. This review intends to inform, educate, and empower all aspiring and practicing SLET surgeons to optimize their clinical outcomes and to have maximal positive impact on the lives of the individuals affected by unilateral or bilateral chronic LSCD.

Simple limbal epithelial transplantation: Current status and future perspectives

Damage to limbal stem cells as a result of injury or disease can lead to limbal stem cell deficiency (LSCD). This disease is characterized by decreased vision that is often painful and may progress to blindness. Clinical features include inflammation, neovascularization, and persistent cornea epithelial defects. Successful strategies for treatment involve transplantation of grafts harvested from the limbus of the alternate healthy eye, called conjunctival‐limbal autograft (CLAU) and transplantation of limbal cell sheets cultured from limbal biopsies, termed cultured limbal epithelial transplantation (CLET). In 2012, Sangwan and colleagues presented simple limbal epithelial transplantation (SLET), a novel transplantation technique that combines the benefits of CLAU and CLET and avoids the challenges associated with both. In SLET a small biopsy from the limbus of the healthy eye is divided and distributed over human amniotic membrane, which is placed on the affected cornea. Outgrowth occurs from each small explant and a complete corneal epithelium is typically formed within 2 weeks. Advantages of SLET include reduced risk of iatrogenic LSCD occurring in the healthy cornea at harvest; direct transfer circumventing the need for cell culture; and the opportunity to perform biopsy harvest and transplantation in one operation. Success so far using SLET is comparable with CLAU and CLET. Of note, 336 of 404 (83%) operations using SLET resulted in restoration of the corneal epithelium, whereas visual acuity improved in 258 of the 373 (69%) reported cases. This review summarizes the results of 31 studies published on SLET since 2012. Progress, advantages, challenges, and suggestions for future studies are presented.

Tear Film Instability and Meibomian Gland Dysfunction Correlate with the Pterygium Size and Thickness Pre- and Postexcision in Patients with Pterygium

Purpose

This study aimed to evaluate the effects of excision on dry eye and meibomian gland dysfunction (MGD) in individuals with pterygium, before and after surgery. It also aimed to investigate how these effects correlate with the size and thickness of the pterygium.

Subjects and Methods

63 eyes from 63 patients with primary nasal pterygium and 45 eyes from 45 healthy volunteers without ocular pathologies were enrolled in this study. 63 eyes from 63 patients underwent pterygium surgery. ImageJ software was used to calculate the pterygium size based on images of the anterior segments. Anterior segment spectral domain optical coherence tomography (SD-OCT) was performed preoperatively to measure the thickness of the pterygium 1 mm anterior to the nasal scleral spur. The ocular surface disease index (OSDI), Schirmer I Test (SIT), and MGD grade were used to evaluate the eyes, and the eyes were imaged using the noninvasive keratograph average tear film breakup time (NIBUTav), tear meniscus height (TMH), meiboscore, and lipid layer grading tools of the Oculus® Keratograph 5M, preoperatively and at 1, 3, and 6 months postoperatively.

Results

The OSDI, NIBUTav, lid margin abnormality, meiboscore, and lipid layer grading values differed significantly in the pterygium patients in comparison with the controls (p < 0.01 for all scores). However, the SIT and TMH values were unchanged between the two groups (all p > 0.05). Multivariate regression analysis demonstrated that the NIBUTav, meiboscore, and lipid layer grading score was significantly correlated with the pterygium parameters, such as size and thickness. The postoperative OSDI, NIBUTav, lid margin abnormality, and lipid layer grading values improved significantly (p < 0.05 for all scores). The SIT, TMH, and meiboscore results did not differ significantly between the pre- and postoperative values (p > 0.05). Among the conventional and automated indexes, at 1 month postoperatively, SIT and TMH were significantly correlated with the pterygium parameters, but no correlation was observed at 3 and 6 months postoperatively. The OSDI, NIBUTav, meiboscore, and lipid layer grading values at 1, 3, and 6 months postoperatively were significantly correlated with the pterygium parameters.

Conclusion

Abnormal tear film and meibomian gland (MG) function improved following pterygium excision in the patients with primary pterygium, which was associated with uncomfortable ocular symptoms. Pterygium parameters, such as size and thickness, correlated with the dry eye and MGD indexes in patients pre- and postoperatively, potentially offering a novel strategy for clinical implementation of pterygium excision surgery.

Simple limbal epithelial transplantation for recurrent pterygium: A case series

PURPOSE

Pterygium recurrence is a common complication of pterygium removal. Multiple surgical and medical approaches have been utilized to reduce recurrence rates. The present case series proposes a novel way to treat recurrent pterygia, by using the simple limbal epithelial transplantation (SLET) technique.

OBSERVATIONS

The cases of four patients who presented with recurrent pterygium were reviewed. In all four of the cases reported, the SLET procedure went without complication. There were no significant recurrences at each of the patient's most recent follow-up visits.

CONCLUSIONS AND IMPORTANCE

This is the first report of SLET being used as a treatment modality for recurrent pterygium. Further studies are required to more reliably demonstrate the utility of the procedure in this clinical circumstance, but our results are encouraging that in select patients, this may be a viable option in treating aggressive recurrent pterygia.

Emerging Therapeutic Strategies for Limbal Stem Cell Deficiency

Identification and characterization of the limbal epithelial stem cells (LESCs) has proven to be a major accomplishment in anterior ocular surface biology. These cells have been shown to be a subpopulation of limbal epithelial basal cells, which serve as the progenitor population of the corneal epithelium. LESCs have been demonstrated to play an important role in maintaining corneal epithelium homeostasis. Many ocular surface diseases, including intrinsic (e.g., Sjogren's syndrome) or extrinsic (e.g., alkali or thermal burns) insults, which impair LESCs, can lead to limbal stem cell deficiency (LSCD). LSCD is characterized by an overgrowth of conjunctival-derived epithelial cells, corneal neovascularization, and chronic inflammation, eventually leading to blindness. Treatment of LSCD has been challenging, especially in bilateral total LSCD. Recently, advances in LESC research have led to novel therapeutic approaches for treating LSCD, such as transplantation of the cultured limbal epithelium. These novel therapeutic approaches have demonstrated efficacy for ocular surface reconstruction and restoration of vision in patients with LSCD. However, they all have their own limitations. Here, we describe the current status of LSCD treatment and discuss the advantages and disadvantages of the available therapeutic modalities.

Simple limbal epithelial transplantation: a review on current approach and future directions

Simple limbal epithelial transplantation is a recently developed technique for treating limbal stem cell deficiency caused by ocular burns. A small limbal biopsy from the donor eye, usually from the patient's healthy eye, is excised and dissected into multiple pieces. An amniotic membrane is atttached using fibrin glue on the diseased eye after removing the conjunctivalized pannus from the corneal surface. The limbal biopsy pieces are placed onto the amniotic membrane, fixed with fibrin glue, followed by bandaging of the ocular surface with a contact lens. This technique (auto simple limbal epithelial transplantation) offers easier surgical manipulations and economic advantages over other techniques for the treatment of limbal stem cell deficiency. We therefore review simple limbal epithelial transplantation along with recent modifications in the technique and case studies, including challenges and failures.

Releasable Single Suture for Primary Pterygium Excision With a Conjunctival Autograft

PURPOSE

To evaluate the efficacy of a releasable single suture for pterygium excision with a conjunctival autograft (CAG).

METHODS

Retrospective case series at a tertiary eye care center in central India was conducted. Medical records of 150 patients, who underwent primary pterygium excision with a CAG secured by a single releasable 10-0 nylon suture in the last year were reviewed. The surgical duration was noted. The suture was released on the first postoperative day under topical anesthesia. Patients were followed up until 1 year. At each visit, factors studied were patient comfort [pain grading on a visual analog scale], graft apposition, complications, and recurrence.

RESULTS

Mean age of patients was 39 ± 11 years. Most patients in our study were female (58.7%). Sixty percent of pterygia were of Tan grade 2. The mean duration of surgery was 4.8 ± 1.3 minutes. The maximum size of the CAG was 6 mm (3-6 mm). The graft retraction rate was 5.3% (1 mm retraction in the CAG more than 5.5 mm) with no event of graft loss. Four percent of patients had grade 1 recurrence.

CONCLUSIONS

Releasable single suture may offer a good and simple alternative, which uses the gold standard technique of the CAG with exclusion of suture-related complications.

[Limbal epithelial stem cell transplantation : Current state and perspectives]

Homeostasis of the corneal surface is maintained by epithelial stem cells localized in the limbus. Multiple intrinsic factors or external injuries can destroy the delicate microenvironment of limbal epithelial stem cells causing a state which is termed limbal stem cell deficiency (LSCD). In such cases, re-epithelialization of the cornea is drastically impeded and conjunctival epithelium starts to extend beyond the limbus and to invade the corneal surface. In partial LSCD, a superficial keratectomy combined with an amniotic membrane is advised and helpful to restore an intact, healthy ocular surface. In complete LSCD, stem cell transplantation is the only curative option. Before any reconstruction, causative factors and comorbidities should be eliminated or at least optimized. In cases of unilateral LSCD, stem cells can be obtained from the contralateral eye. Advanced surgical and cultivation techniques pursue a gentle, tissue-saving procedure of harvesting a limbal biopsy from the only healthy functioning eye. Patients with bilateral involvement can be treated with allogeneic tissue, but will require long-term systemic immunosuppressive therapy. Another newer option is the use of autologous, but noncorneal epithelial cells as a tissue source, e.g., buccal mucosa. Future studies will focus on the further development of cellular expansion and/or the establishment of new alternative sources for replacing limbal epithelial stem cells.