Making the decision to donate eyes: Perspectives from the families of the deceased in Madurai, India

Purpose:

To identify factors affecting family members' decision whether to donate eye organs.

Methods:

A community-based case-control study based on in-home interviews with families of deceased individuals who had or had not donated eye organs, in Madurai district, Tamil Nadu, India. Data collected were knowledge and awareness of eye donations, whether the deceased individual had expressed or pledged willingness to donate, and family members' attitudes and willingness to donate their own eye organs.

Results:

Seventy-six families of donors and 256 families of non-donors completed the survey. Multivariable analysis showed that the following variables were significantly associated with a donation: age, whether the deceased had registered for eye donation, pre-expressed willingness of deceased to donate, whether family members personally know beneficiaries of eye donations, and higher score on a scale evaluating knowledge and awareness about eye donation. The majority of donors' families (71%) had been encouraged by someone to donate. Among non-donor families, a substantially larger fraction (52.8%) indicated they would have donated had someone reminded or encouraged them to do so, in comparison with those who indicated lack of awareness or knowledge (14.5%).

Conclusion:

Community programs are likely to be effective if they encourage individuals to pledge their eyes or express their willingness to donate their eyes to family members in advance of death; they increase public awareness of the value of eye donation. A friend, family member, neighbor or counselor approaching bereaved families and having a dialogue about eye donation would substantially increase the probability of a decision to donate.

Techniques, Outcomes, and Complications of Preloaded, Trifolded Descemet Membrane Endothelial Keratoplasty Using the DMEK EndoGlide

PURPOSE

To describe 2 insertion techniques, outcomes, and complications of preloaded, trifolded Descemet membrane endothelial keratoplasty (DMEK) cases using the DMEK EndoGlide inserter.

METHODS

This retrospective, consecutive case series analyzed the first 35 cases using the DMEK EndoGlide performed between October 2018 and October 2019 at a single center. Preloaded, trifolded DMEK tissues were delivered through a fluid-injected or pull-through technique. To inject the tissue, a burst of fluid was delivered into the lumen of the injector with a second instrument. Postoperatively, best-spectacle corrected visual acuity (BSCVA), pachymetry, graft survival, and complications were assessed.

RESULTS

Thirty-five eyes of 29 patients underwent DMEK alone (n = 11), with cataract surgery (n = 21), or with additional surgeries (n = 3). Of these, 19 (54.3%) grafts were injected. Video analysis revealed a median time of 3.5 minutes from graft insertion to opening for gas insertion. Median preoperative BSCVA of 0.398 logMAR improved to 0.097 logMAR (P = 0.02) at 9 months. Median pachymetry decreased from 619 μm to 551 μm (P = 0.03) at 9 months. Median donor endothelial cell count of 2890.5 cells/mm2 reduced to 2123 cells/mm2 (26.6% endothelial cell loss; P = 0.008) 6 months postoperatively. One (2.9%) graft failed due to inverted marking at the eye bank and subsequent reverse implantation.

CONCLUSIONS

Pre-loaded, tri-folded tissues can be implanted with acceptable levels of endothelial cell loss. We describe a no-touch method of injecting pre-loaded, tri-folded tissue and highlight incorrect marking as a potential complication. This may not be identifiable intraoperatively due to lack of scroll formation.

Sensor-Embedded Automatic Grasping Forceps for Precise Corneal Suture in Penetrating Keratoplasty

In penetrating keratoplasty (PKP), the proper corneal suture placement is very important for successful transplantation and restoring functional vision. Generating sutures with accurate depth is difficult for the surgeon because of the tissue’s softness, lack of depth information, and hand tremors. In this paper, an automatic cornea grasping device is proposed, which detects when the device reaches the target suture depth. When the device reaches the target depth, the device rapidly grasps the cornea to prevent error induced by human hand tremors. In the paper, the performance of the proposed sensor, the actuator, and the device are experimentally verified with ex vivo experiment. The result showed that the proposed device could enhance the accuracy and precision of the corneal suture depth.

Evaluation of Donor and Recipient Characteristics Involved in Descemet Stripping Automated Endothelial Keratoplasty Outcomes

Aims: To evaluate both donor and recipient features involved in visual acuity restoring and complication insurgence in eyes that have undergone Descemet stripping automated endothelial keratoplasty (DSAEK).

Methods: In this retrospective study, charts of 111 eyes of 96 patients (mean age 70.25 ± 8.58 years) that underwent DSAEK were evaluated. Only Fuch's Distrophy (FD) or Bullous Keratopathy (BK) due to cataract surgery eyes were included. A complete ophthalmic check with endothelial cell density (ECD) and central corneal thickness (CCT) measurement was performed before surgery and at 1, 3, 6, and 12 months follow-up. Each DSAEK was performed by the same well-trained surgeon; only pre-cut lenticules, provided by same Eye Bank, were implanted.

Results: A total of 48 (43%) complications have been observed (most of them were 22 partial graft detachments and 17 IOP spikes). At the last follow-up (mean: 8.58 ± 4.09 months), a significant increase (p < 0.05) of best corrected visual acuity (BCVA) was detected. Overall mean BCVA of the eyes evaluated was 0.40 ± 0.43 LogMAR with BK eyes showing a significantly higher improvement (p < 0.05) compared to FD eyes. The only factor showing a significant correlation (p < 0.05) with visual acuity enhancement was the implant of a lenticule thinner than 100 μm. Recipient features significantly (p < 0.05) associated with complications observed after surgery were glaucoma and diabetes mellitus.

Conclusion: The use of a graft thinner than 100 μm can provide better visual acuity recovery while recipients affected by glaucoma or diabetes mellitus are more prone to develop complications after surgery.

Evolution of therapies for the corneal endothelium: past, present and future approaches

Corneal endothelial diseases are leading indications for corneal transplantations. With significant advancement in medical science and surgical techniques, corneal transplant surgeries are now increasingly effective at restoring vision in patients with corneal diseases. In the last 15 years, the introduction of endothelial keratoplasty (EK) procedures, where diseased corneal endothelium (CE) are selectively replaced, has significantly transformed the field of corneal transplantation. Compared to traditional penetrating keratoplasty, EK procedures, namely Descemet's stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK), offer faster visual recovery, lower immunological rejection rates, and improved graft survival. Although these modern techniques can achieve high success, there are fundamental impediments to conventional transplantations. A lack of suitable donor corneas worldwide restricts the number of transplants that can be performed. Other barriers include the need for specialized expertise, high cost, and risks of graft rejection or failure. Research is underway to develop alternative treatments for corneal endothelial diseases, which are less dependent on the availability of allogeneic tissues - regenerative medicine and cell-based therapies. In this review, an overview of past and present transplantation procedures used to treat corneal endothelial diseases are described. Potential novel therapies that may be translated into clinical practice will also be presented.

Reper intraocular lens with artificial iris: implantation techniques and outcomes

The authors describe the surgical techniques to implant a novel intraocular lens with artificial iris (Reper) in patients affected by traumatic aphakia and aniridia. Two surgical approaches are proposed: implantation by suture-loaded cartridge and "open sky" implantation combined with penetrating keratoplasty. The method of establishing the exact position of the scleral fixation points and the pre-assembly of the suture of Reper before its implantation are the main novel proposed surgical procedures. The rationale is to minimize surgical procedures in the anterior chamber and to prevent knot loosening and lens tilting. The simultaneous treatment of aphakia and aniridia with a single prosthesis, the stability of the Reper and the functional, anatomical and aesthetic outcomes obtained are the highlighted advantages in this study.

Effect of COVID-19-related lockdown on ophthalmic practice in Italy: A report from 39 institutional centers

BACKGROUND/OBJECTIVES

To compare the number of eye surgical procedures performed in Italy in the 2 months following the beginning of lockdown (study period) because of COVID-19 epidemic with those performed in the two earlier months of the same year (intra-year control) and in the period of 2019 corresponding to the lockdown (inter-year control).

METHODS

Retrospective analysis of surgical procedures carried out at 39 Academic hospitals. A distinction was made between elective and urgent procedures. Intravitreal injections were also considered. Percentages for all surgical procedures and incidence rate ratios (IRR) for rhegmatogenous retinal detachment (RRD) events were calculated. A p value <0.05 was considered significant.

RESULTS

A total of 20,886 versus 55,259 and 56,640 patients underwent surgery during the lockdown versus intra-and inter-year control periods, respectively. During the lockdown, only 70% of patients for whom an operation/intravitreal injection was recommended, finally underwent surgery; the remaining patients did not attend because afraid of getting infected at the hospital (23%), taking public transportation (6.5%), or unavailable swabs (0.5%). Elective surgeries were reduced by 96.2% and 96.4%, urgent surgeries by 49.7% and 50.2%, and intravitreal injections by 48.5% and 48.6% in the lockdown period in comparison to intra-year and inter-year control periods, respectively. IRRs for RRDs during lockdown dropped significantly in comparison with intra- and inter-year control periods (CI: 0.65-0.80 and 0.61-0.75, respectively, p < 0.001 for both).

CONCLUSION

This study provides a quantitative analysis of the reduction of eye surgical procedures performed in Italy because of the COVID-19 epidemic.

Indications of Keratoplasty and Outcomes of Deep Anterior Lamellar Keratoplasty Compared to Penetrating Keratoplasty

Background

Corneal diseases are a significant cause of visual impairment and blindness. Despite the treatable nature of many corneal diseases before visual demise, many cases of advanced disease necessitating keratoplasty for visual rehabilitation are encountered. A mismatch between the number of corneal donors and potential recipients also exists worldwide, with underutilization of certain types of keratoplasty techniques that may allow more efficient use of this limited resource.

Methodology

A retrospective cohort study of all cases of optical corneal transplantations performed from January 1, 2015 to October 31, 2020 was performed. Indications for keratoplasty, type of keratoplasty, complications, intraocular pressure elevation, and best corrected visual acuity (BCVA) by category and range at different time intervals were collected and analyzed. Findings were compared between penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) for all indications, specifically for keratoconus (KCN).

Results

A total of 58 corneal transplants meeting our criteria were performed during the study period. PK was performed for 29 eyes, DALK for 28 eyes, and endothelial keratoplasty for one eye. The most frequently encountered indication was KCN (62.1%). The number of eyes with BCVA of 20/100 or better increased from preoperative BCVA, 37/58 eyes had BCVA worse than 20/100 before keratoplasty (63.8%), while at the time of last follow-up 45/58 eyes had BCVA of 20/100 or better (77.6%). At the time of last follow-up 16/58 had BCVA in the range of 20/20 to 20/40 (27.6%) and 29/58 eyes had BCVA in the range of 20/50 to 20/100 (50%). Comparison of all cases of PK to DALK for all indications showed significantly better BCVA by category at one year, at last follow-up, and BCVA range at last follow-up (p = 0.032, 0.001, and 0.014, respectively). Although better visual acuity results by category and range at one year and last follow-up, respectively, were observed in more patients undergoing DALK than PK, for KCN the results were not statistically significant (p = 1.00, 1.00, 0.417, and 0.374, respectively). Overall, 70% of recorded complications, intraocular pressure (IOP) elevations, and graft rejections were seen in eyes that underwent PK; however, these findings were not statistically significant (p = 0.297). Graft failures occurred more frequently with PK than deep anterior keratoplasty when analyzed for all indications of keratoplasty (p = 0.010).

Conclusions

Despite advancement and improvements in surgical techniques, statistics continue to show underutilization of the invaluable resource of donor corneas, with PK still being performed more than DALK for diseases that do not affect the endothelium. Our study found superior visual acuity outcomes of DALK as well as the advantages of less frequent complications, IOP elevations, graft rejections, and graft failures. We encourage ophthalmologists to utilize DALK in appropriate candidates to more fully utilize the scarce and potentially vision-restoring resource of donor corneal tissue.

Use of Post-transplant Cyclophosphamide Treatment to Build a Tolerance Platform to Prevent Liquid and Solid Organ Allograft Rejection

Corneal transplantation (CT) is the most frequent type of solid organ transplant (SOT) performed worldwide. Unfortunately, immunological rejection is the primary cause of graft failure for CT and therefore advances in immune regulation to induce tolerance remains an unmet medical need. Recently, our work and others in pre-clinical studies found that cyclophosphamide (Cy) administered after (“post-transplant,” PTCy) hematopoietic stem cell transplantation (HSCT), i.e., liquid transplants is effective for graft vs. host disease prophylaxis and enhances overall survival. Importantly, within the past 10 years, PTCy has been widely adopted for clinical HSCT and the results at many centers have been extremely encouraging. The present studies found that Cy can be effectively employed to prolong the survival of SOT, specifically mouse corneal allografts. The results demonstrated that the timing of PTCy administration is critical for these CT and distinct from the kinetics employed following allogeneic HSCT. PTCy was observed to interfere with neovascularization, a process critically associated with immune rejection of corneal tissue that ensues following the loss of ocular “immune privilege.” PTCy has the potential to delete or directly suppress allo-reactive T cells and treatment here was shown to diminish T cell rejection responses. These PTCy doses were observed to spare significant levels of CD4⁺ FoxP3⁺ (Tregs) which were found to be functional and could readily receive stimulating signals leading to their in vivo expansion via TNFRSF25 and CD25 agonists. In total, we posit future studies can take advantage of Cy based platforms to generate combinatorial strategies for long-term tolerance induction.

Absence of Severe Acute Respiratory Syndrome-Coronavirus-2 RNA in Human Corneal Tissues

PURPOSE

To examine corneal tissue for severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) positivity regarding implications for tissue procurement, processing, corneal transplantation, and ocular surgery on healthy patients. We performed quantitative reverse transcription-polymerase chain reaction qRT-PCR-testing for SARS-CoV-2 RNA on corneal stroma and endothelium, bulbar conjunctiva, conjunctival fluid swabs, anterior chamber fluid, and corneal epithelium of coronavirus disease 2019 (COVID-19) postmortem donors.

METHODS

Included in this study were 10 bulbi of 5 COVID-19 patients who died because of respiratory insufficiency. Informed consent and institutional review board approval was obtained before this study (241/2020BO2). SARS-CoV-2 was detected by using a pharyngeal swab and bronchoalveolar lavage. Tissue procurement and tissue preparation were performed with personal protective equipment (PPE) and the necessary protective measures. qRT-PCR-testing was performed for each of the abovementioned tissues and intraocular fluids.

RESULTS

The qRT-PCRs yielded no viral RNA in the following ocular tissues and intraocular fluid: corneal stroma and endothelium, bulbar-limbal conjunctiva, conjunctival fluid swabs, anterior chamber fluid, and corneal epithelium.

CONCLUSIONS

In this study, no SARS-CoV-2-RNA was detected in conjunctiva, anterior chamber fluid, and corneal tissues (endothelium, stroma, and epithelium) of COVID-19 donors. This implicates that the risk for SARS-CoV-2 infection using corneal or conjunctival tissue is very low. However, further studies on a higher number of COVID-19 patients are necessary to confirm these results. This might be of high importance for donor tissue procurement, processing, and corneal transplantation.

Corneal transplantation during COVID-19 pandemic: need for special considerations-A live review

Corneal blindness is the fourth leading cause of blindness worldwide, with 10 million people having bilateral corneal blindness, nearly 80% of all corneal blindness cases are avoidable and are reversible. Corneal transplantation (CT) is the most frequently performed type of transplant across the world. This review was conducted with the objective of identifying if it is safe to harvest the cornea from the patients died due to COVID-19 and preventing the chances of transmission from donor to the recipient or healthcare worker handling the harvested cornea. A total of 45 articles were found with the keywords and out of all, only 16 fulfilled the inclusion criteria. RT-PCR is the technique of choice for detection of virus in the corpse and the sample analyzed was a pharyngeal swab. Available literature states unavailability of sufficient evidence-based studies proving presence of virus in the cornea or tear of COVID affected patients There is no proven consensus on presence of Virus in cornea. It is important to follow preferred practice guidelines so as to restart eye banking and do at least the emergency surgeries without having risk of disease transmission and keeping ourselves safe.

Visual outcomes in advanced keratoconus using different strategies: Scleral lens, intracorneal ring segment and lamellar keratoplasty

PURPOSE

To compare VA outcomes in patients with advanced keratoconus wearing SCL or after ICRS or DALK. In addition, determine the percentage of complimentary treatments after ICRS and DALK, and which of these was fitting a SCL, and final visual acuity (f-VA) results.

METHODS

Retrospective case series analyzed 55 eyes with advanced keratoconus fitted with SCL, or after ICRS or a DALK between 2010 and 2018. The variables analyzed were sex, age, UDVA, CDVA, SEQ, K-readings, and f-VA after complimentary treatments.

RESULTS

Twenty-eight eyes underwent a DALK, 14 were fitted with a SCL, and other 13 underwent ICRS insertion. Patients after DALK and after ICRS showed statistically significant improvement in UDVA and CDVA after surgery, with no difference between these groups. Patients fitted with SCL showed statistically higher CDVA improvement when compared to ICRS. After DALK and ICRS, respectively, nine eyes (32.14%) and seven eyes (53.85%) were fitted with SCL. Comparison between f-VA with SCL in three groups showed that the best result was achieved in DALK + SCL, with statistically significant difference to only SCL.

CONCLUSION

We showed that the CDVA of eyes fitted with SCL without any surgical treatment was statistically better than CDVA of eyes after ICRS insertion. After DALK and ICRS insertion, many patients needed a complimentary treatment to improve CDVA. The most chosen treatment was fitting a SCL. After this, all eyes showed statistically significant improvement in f-VA, with statistically better results for DALK + SCL when compared to SCL fitted in advanced keratoconus without any surgical treatment.

The role of soluble programmed death protein-1 (sPD-1) and soluble programmed death ligand-1 (sPD-L1) in rat corneal transplantation rejection

BACKGROUND

Immunological rejection is one of the problems in corneal transplantation. Recently, some research found out that soluble programmed death protein-1 (sPD-1) and soluble programmed death ligand protein-1 (sPD-L1) play a significant role in immunologic suppression.

OBJECTIVES

To explore expression of sPD-1 and sPD-L1 in a penetrative corneal transplantation model and its relationship with transplant rejection.

MATERIAL AND METHODS

Autologous corneal transplantation rat models and allogeneic corneal transplantation rat models were used as the control group and the experimental group, respectively. Changes of the transplanted grafts were observed under a slit-lamp microscope. Hematoxylin-eosin (H&E) staining was applied to examine the histopathological features of the corneal grafts. Flow cytometry was used to analyze CD4+CD25+Treg in the serum and spleen. The sPD-1, sPD-L1, interleukin 10 (IL-10) and interleukin 4 (IL-4) levels in serum and the aqueous humor of the rats were detected using enzyme-linked immunosorbent assay (ELISA).

RESULTS

After the operation, no transplant rejection occurred in the control group. Flow cytometry results showed that expressions of CD4+CD25+Treg in serum in the experimental group were lower than those in the control group (p < 0.05). The ELISA results showed that after the operation, sPD-1 and sPD-L1 expression levels in serum in the experimental group were higher than in the control group (all p < 0.05). After the operation, lL-10 and IL-4 content in serum in the experimental group was lower than in the control group (all p < 0.05). The sPD-1/sPD-L1 ratio in the experimental group was higher than in the control group.

CONCLUSIONS

Increases of sPD-1 content and decreases of CD4+CD25+Treg, IL-10 and IL-4 levels may be involved in corneal allograft rejection. Dynamic detection of the content of sPD-1 and sPD-L1 in serum and aqueous humor after the operation would help in understanding the local immune response in a clinical setting and predicting the occurrence of corneal graft rejection.

Distribution and Expression of the Adhesion Molecule CD44 on Human Corneal Grafts Is Not Altered by Chemotherapy

BACKGROUND/AIM

Acceptance of corneas from donors with a malignancy remains controversial, especially for donors with hematological malignancy. The aim of our study was to examine, for the first time in literature, any structural differences in the integrity of the corneal grafts from donors who have received and from those who have not received chemotherapy.

MATERIALS AND METHODS

The immunohistochemical expression of CD44 was examined in 12 corneal grafts obtained from 8 donors. Three grafts were obtained from 2 donors who had received chemotherapy and the rest were obtained from 6 donors who had not received any kind of chemotherapy.

RESULTS

Epithelial cells expressed the CD44 molecule in all grafts of both groups. No CD44 expression was noticed on endothelial cells or in the stroma.

CONCLUSION

Tumorigenesis and the consequent chemotherapy did not affect the structure and integrity of the corneal tissue in the examined samples. We suggest that corneal grafts from cancer donors are safe and functionally equals to grafts obtained from non-cancer donors.

Corneal Transplant Follow-up Study II: a randomised trial to determine whether HLA class II matching reduces the risk of allograft rejection in penetrating keratoplasty

PURPOSE

A randomised trial to test the hypothesis that human leucocyte antigen (HLA) class II matching reduces the risk of allograft rejection in high-risk penetrating keratoplasty (PK).

METHODS

All transplants were matched for HLA class I antigens (≤2 mismatches at the A and B loci) and corneas were allocated to patients by cohort minimisation to achieve 0, 1 or 2 HLA class II antigen mismatches. The corneal transplants (n=1133) were followed for 5 years. The primary outcome measure was time to first rejection episode.

RESULTS

Cox regression analysis found no influence of HLA class II mismatching on risk of immunological rejection (HR 1.13; 95% CI 0.79 to 1.63; p=0.51). The risk of rejection in recipients older than 60 years was halved compared with recipients ≤40 years (HR 0.51; 95% CI 0.36 to 0.73; p=0.0003). Rejection was also more likely where cataract surgery had been performed after PK (HR 3.68; 95% CI 1.95 to 6.93; p<0.0001). In univariate analyses, preoperative factors including chronic glaucoma (p=0.02), vascularisation (p=0.01), inflammation (p=0.03), ocular surface disease (p=0.0007) and regrafts (p<0.001) all increased the risk of rejection. In the Cox model, however, none of these factors was individually significant but rejection was more likely where≥2 preoperative risk factors were present (HR 2.11; 95% CI 1.26 to 3.47; p<0.003).

CONCLUSIONS

HLA class II matching, against a background of HLA class I matching, did not reduce the risk of allograft rejection. Younger recipient age, the presence of ≥2 preoperative risk factors and cataract surgery after PK all markedly increased the risk of allograft rejection.

TRIAL REGISTRATION NUMBER

ISRCTN25094892.

Microbial keratitis and clinical outcomes following penetrating and endothelial keratoplasty

PURPOSE

The goal of this study was to review the incidence, risk factors and outcomes of microbial keratitis after penetrating keratoplasty (PK) and endothelial keratoplasty (EK).

METHODS

The electronic medical records at Wills Eye Hospital were queried for cases of microbial keratitis following PK or EK performed between 1 May 2007 and 1 September 2018. Charts were reviewed to obtain demographic data, transplant characteristics, details of microbial keratitis, graft survival and clinical outcomes.

RESULTS

During the study period, 2098 transplants were performed in 1601 patients. Of these, 1267 (60.4%) were PKs and 831 (39.6%) were EKs. We identified 86 (4.1%) cases of subsequent microbial keratitis. The incidence of microbial keratitis after PK was significantly higher than after EK (5.9% versus 1.3%; p = 0.005). Furthermore, the rate of infection was higher after repeat transplants (either PK or EK) compared to initial keratoplasties (5.5% versus 3.4%; p = 0.02). Twenty-six (32.1%) grafts remained clear at most recent follow-up after microbial keratitis, and the proportion of clear grafts was higher after EK than PK (66.7% versus 27.8%; p = 0.03).

CONCLUSION

Rates of microbial keratitis were significantly higher after PK compared to EK, and repeat transplantation was a risk factor for microbial keratitis. To the best of our knowledge, there is no prior study in the literature evaluating microbial keratitis rates after PK and EK and comparing outcomes.

Xen Gel Stent as a minimally invasive option for intraocular pressure control after DSAEK: A case study

PURPOSE

This case study describes the implantation of a Xen45 Gel Stent in a patient that had previously undergone Descemet stripping automated endothelial keratoplasty (DSAEK). Glaucoma might worsen after corneal transplant, and while medical treatment is the first-line therapy to achieve intraocular pressure (IOP) control, a surgical approach is required when medication does not reach the target IOP.

METHODS

In 2017, the patient underwent treatment in both eyes with ocular hypotensive eye drops for pseudoexfoliative (PXF) glaucoma. In May 2017, DSAEK was performed on the right eye because of the presence of a pseudophakic bullous keratopathy. An increase in IOP, resistant to medical treatment, was observed after the corneal transplant. In November 2017, a Xen45 Gel Stent was implanted.

RESULTS

The patient had a positive outcome with a Xen45 Gel Stent implant in surgical glaucoma treatment after DSAEK. The case demonstrated excellent postoperative IOP control, stable vision and a healthy ocular graft at short-term and long-term follow-ups.

CONCLUSION

Studies with larger numbers of patients in this particular form of therapy are required. Nevertheless, Xen45 Gel Stent implantation appears to be a promising option in preventing or limiting glaucoma in patients who have previously undergone DSAEK. It is a brief, minimally invasive procedure with reduced postoperative inflammation, faster visual recovery and a lower risk of graft damage or hypotony, even in the case of PXF glaucoma.

Long-term restoration of corneal sensitivity in neurotrophic keratopathy after rhNGF treatment

BACKGROUND

To report the long-term effects of the new rhNGF treatment on corneal sensitivity in patients with.

CASES PRESENTATION

We present three cases of corneal ulcers due to NK that were treated with rhNGF. In each patient wound healing evolution was documented by clinical pictures and corneal sensitivity measured by Cochet-Bonnet aesthesiometry. Best corrected visual acuity and Type I Schirmer test were also assessed neurotrophic keratopathy.All patients healed within 8 weeks and NK showed no recurrences in the mean follow-up period of 35 weeks. Each subject showed a significant increase of corneal sensitivity and tear secretion, with concomitant improvement in visual acuity.

CONCLUSION

Corneal sensitivity, measured by Cochet-Bonnet aesthesiometer, markedly increased in all eyes. Further studies are warranted to demonstrate a possible mechanism of nerve restoration with rhNGF treatment.

THERMAL ANALYSIS OF INTRAOCULAR ELECTRONIC DISPLAY PROJECTOR VISUAL PROSTHESIS

Corneal opacity is a leading cause of blindness, accounting for about 4% of global blindness. With corneal opacity, light is unable to pass through the cornea to form a clear image on the retina, resulting in blindness. To address this condition, an intraocular projection device has been designed. This device, while in use, would produce heat. According to international standard regulations, the temperature on the surface of the tissues should not increase more than 2°C due to medical devices. In order to establish the power budget of this intraocular electronic device, a steady state thermal finite element analysis was conducted on two different eye models. The device was placed at 9.98 mm from the retina, and was seen to run up to a maximum power of 82 mW for the first model and 91 mW for the second model. To reduce heating of tissues, the device was extended by 0.5 mm to create an air gap which acted as an insulator. The temperature in the nearest living tissue then dropped below the prescribed limit of 2°C at 100 mW.

Lost to follow-up: reasons and characteristics of patients undergoing corneal transplantation at Tenwek Hospital in Kenya, East Africa

Introduction

corneal transplantation is a surgical procedure requiring consistent long-term follow-up to maximize the chance of graft survival. The purpose of this study was to explore patient characteristics and reasons for being lost to follow-up (LTFU).

Methods

a retrospective review of clinical records from January 2012 to October 2014 was conducted of patients who received corneal transplantation at Tenwek Hospital. At the time of chart review, all patients who provided a mobile phone number were contacted to answer a phone questionnaire. Logistic regression was used to assess the association of each patient characteristic, separately, with the outcome of LTFU.

Results

of the 118 patients that met inclusion criteria, 40 (33.9%) were considered LTFU by failing to follow up at Tenwek Hospital to at least one year postoperatively. The odds of LTFU for patients age 60 and older were 3.78 times that of those who were 18-59 (95% CI: 1.21-11.80]; p-value=0.02). The odds of LTFU for patients with a preoperative diagnosis of pseudophakic bullous keratopathy were 3.83 times that of those with a preoperative diagnosis of keratoconus (95% CI: [1.13-12.94]; p-value=0.03). Education level, employment status, distance from the hospital, and possession of a mobile contact number appeared marginally associated with follow-up status, though not statistically significant at the 0.05 significance level. Financial barriers were the most commonly cited reason for LTFU (42.4%, n=14).

Conclusion

certain reasons and patient characteristics may be associated with follow-up adherence. Identifying these factors may help providers identify patients who are at a higher risk of LTFU and influence providers in medical decision-making and system-based interventions when offering corneal transplantation.

Deep Learning for Assessing the Corneal Endothelium from Specular Microscopy Images up to 1 Year after Ultrathin-DSAEK Surgery

Purpose

To present a fully automatic method to estimate the corneal endothelium parameters from specular microscopy images and to use it to study a one-year follow-up after ultrathin Descemet stripping automated endothelial keratoplasty.

Methods

We analyzed 383 post ultrathin Descemet stripping automated endothelial keratoplasty images from 41 eyes acquired with a Topcon SP-1P specular microscope at 1, 3, 6, and 12 months after surgery. The estimated parameters were endothelial cell density (ECD), coefficient of variation (CV), and hexagonality (HEX). Manual segmentation was performed in all images.

Results

Our method provided an estimate for ECD, CV, and HEX in 98.4% of the images, whereas Topcon's software had a success rate of 71.5% for ECD/CV and 30.5% for HEX. For the images with estimates, the percentage error in our method was 2.5% for ECD, 5.7% for CV, and 5.7% for HEX, whereas Topcon's software provided an error of 7.5% for ECD, 17.5% for CV, and 18.3% for HEX. Our method was significantly better than Topcon's (P < 0.0001) and was not statistically significantly different from the manual assessments (P > 0.05). At month 12, the subjects presented an average ECD = 1377 ± 483 [cells/mm2], CV = 26.1 ± 5.7 [%], and HEX = 58.1 ± 7.1 [%].

Conclusions

The proposed method obtains reliable and accurate estimations even in challenging specular images of pathologic corneas.

Translational Relevance

CV and HEX, not currently used in the clinic owing to a lack of reliability in automatic methods, are useful biomarkers to analyze the postoperative healing process. Our accurate estimations allow now for their clinical use.

Improving Endothelial Explant Tissue Culture by Novel Thermoresponsive Cell Culture System

AIM

Studying cell migration of corneal endothelial cells in vitro is challenging because the capacity for cell migration needs to be maintained while at the same time the tissue must remain fixed on a rigid substrate. In this study, we report a thermoresponsive culture technique designed to maintain cellular viability, and to reduce tissue handling in order to analyze in vitro endothelial cell migration from corneal grafts.

MATERIALS AND METHODS

As a test tissue, fifteen Quarter-Descemet membrane endothelial keratoplasty (Q-DMEK) grafts were used that were embedded in a three-dimensional culture system using a temperature-reversible hydrogel and cultured over 2-3 weeks in a humidified atmosphere at 37°C and 5% CO₂.

RESULTS

All grafts could be successfully cultured inside the thermoresponsive polymer solution for periods of up to 21 days. Using this system, cell migration could be assessed by light microscopy at fixed time intervals. At the end of the culture period, the gel could be removed from all grafts and immunohistochemistry analysis showed that endothelial cells were able to maintain confluence, viability, and junctional integrity. Some problems were encountered when using the thermoresponsive cell culture system. These were mostly structural inconsistencies during the sol-to-gel transition phase that resulted in the formation of tiny bubbles in the matrix. Additionally, areas with different viscosity resulted in optical distortions showing up as folds throughout the matrix which can persist even after several cycles of culture medium exchange. These effects had impact on the imaging quality but did not affect the viability of the explant tissue.

CONCLUSION

This study proves that temperature-reversible hydrogel is a very useful matrix for studying in vitro corneal endothelial cell migration from explant grafts and allows for subsequent biological investigation after gel removal.

Lentivirus-mediated IL-10-expressing Bone Marrow Mesenchymal Stem Cells promote corneal allograft survival via upregulating lncRNA 003946 in a rat model of corneal allograft rejection

Rationale: Corneal transplantation is an effective treatment to corneal blindness. However, the immune rejection imperils corneal allograft survival. An interventional modality is urgently needed to inhibit immune rejection and promote allograft survival. In our previous study, subconjunctival injections of bone marrow-derived mesenchymal stem cells (BM-MSCs) into a rat model of corneal allograft rejection extended allograft survival for 2 d. In this study, we sought to generate IL-10-overexpressing BM-MSCs, aiming to boost the survival-promoting effects of BM-MSCs on corneal allografts and explore the molecular and cellular mechanisms underlying augmented protection. Methods: A population of IL-10-overexpressing BM-MSCs (designated as IL-10-BM-MSCs) were generated by lentivirus transduction and FACS purification. The self-renewal, multi-differentiation, and immunoinhibitory capabilities of IL-10-BM-MSCs were examined by conventional assays. The IL-10-BM-MSCs were subconjunctivally injected into the model of corneal allograft rejection, and the allografts were monitored on a daily basis. The expression profiling of long noncoding RNA (lncRNA) in the allografts was revealed by RNA sequencing and verified by quantitative real-time PCR. The infiltrating immune cell type predominantly upregulating the lncRNA expression was identified by RNAscope in situ hybridization. The function of the upregulated lncRNA was proved by loss- and gain-of-function experiments both in vivo and in vitro. Results: The IL-10-BM-MSCs possessed an enhanced immunoinhibitory capability and unabated self-renewal and multi-differentiation potentials as compared to plain BM-MSCs. The subconjunctivally injected IL-10-BM-MSCs reduced immune cell infiltration and doubled allograft survival time (20 d) as compared to IL-10 protein or plain BM-MSCs in the corneal allograft rejection model. Further, IL-10-BM-MSCs significantly upregulated lncRNA 003946 expression in CD68⁺ macrophages infiltrating corneal allografts. Silencing and overexpressing lncRNA 003946 in macrophage cultures abolished and mimicked the IL-10-BM-MSCs' suppressing effects on the macrophages' antigen presentation, respectively. In parallel, knocking down and overexpressing the lncRNA in vivo abrogated and simulated the survival-promoting effects of IL-10-BM-MSCs on corneal allografts, respectively. Conclusion: The remarkable protective effects of IL-10-BM-MSCs support further developing them into an effective interventional modality against corneal allograft rejection. IL-10-BM-MSCs promote corneal allograft survival mainly through upregulating a novel lncRNA expression in graft-infiltrating CD68⁺ macrophages. LncRNA, for the first time, is integrated into an IL-10-BM-MSC-driven immunomodulatory axis against the immune rejection to corneal allograft.

A Novel Approach of Harvesting Viable Single Cells from Donor Corneal Endothelium for Cell-Injection Therapy

Donor corneas with low endothelial cell densities (ECD) are deemed unsuitable for corneal endothelial transplantation. This study evaluated a two-step incubation and dissociation harvesting approach to isolate single corneal endothelial cells (CECs) from donor corneas for corneal endothelial cell-injection (CE-CI) therapy. To isolate CECs directly from donor corneas, optimization studies were performed where donor Descemet’s membrane/corneal endothelium (DM/CE) were peeled and incubated in either M4-F99 or M5-Endo media before enzymatic digestion. Morphometric analyses were performed on the isolated single cells. The functional capacities of these cells, isolated using the optimized simple non-cultured endothelial cells (SNEC) harvesting technique, for CE-CI therapy were investigated using a rabbit bullous keratopathy model. The two control groups were the positive controls, where rabbits received cultured CECs, and the negative controls, where rabbits received no CECs. Whilst it took longer for CECs to dislodge as single cells following donor DM/CE incubation in M5-Endo medium, CECs harvested were morphologically more homogenous and smaller compared to CECs obtained from DM/CE incubated in M4-F99 medium (p < 0.05). M5-Endo medium was hence selected as the DM/CE incubation medium prior to enzymatic digestion to harvest CECs for the in vivo cell-injection studies. Following SNEC injection, mean central corneal thickness (CCT) of rabbits increased to 802.9 ± 147.8 μm on day 1, gradually thinned, and remained clear with a CCT of 385.5 ± 38.6 μm at week 3. Recovery of corneas was comparable to rabbits receiving cultured CE-CI (p = 0.40, p = 0.17, and p = 0.08 at weeks 1, 2, and 3, respectively). Corneas that did not receive any cells remained significantly thicker compared to both SNEC injection and cultured CE-CI groups (p < 0.05). This study concluded that direct harvesting of single CECs from donor corneas for SNEC injection allows the utilization of donor corneas unsuitable for conventional endothelial transplantation.

Immune Checkpoints Contribute Corneal Immune Privilege: Implications for Dry Eye Associated with Checkpoint Inhibitors

The eye is provided with immune protection against pathogens in a manner that greatly reduces the threat of inflammation-induced vision loss. Immune-mediated inflammation and allograft rejection are greatly reduced in the eye, a phenomenon called 'immune privilege'. Corneal tissue has inherent immune privilege properties with underlying three mechanisms: (1) anatomical, cellular, and molecular barriers in the cornea; (2) an immunosuppressive microenvironment; and (3) tolerance related to regulatory T cells and anterior chamber-associated immune deviation. This review describes the molecular mechanisms of the immunosuppressive microenvironment and regulatory T cells in the cornea that have been elucidated from animal models of ocular inflammation, especially those involving corneal transplantation, it also provides an update on immune checkpoint molecules in corneal and systemic immune regulation, and its relevance for dry eye associated with checkpoint inhibitor therapy.