Evolution of Corneal Transplantation in the Province of Quebec From 2000 to 2011

Disparities in Access to Corneal Tissue in the Developing World

Corneal disease is a leading cause of blindness worldwide. For most blinding corneal conditions, keratoplasty is the only way of restoring sight. Unfortunately, access to corneal transplantation is widely variable, most notably due to the lack of suitable donor material. There exists significant disparity between the developed and developing world when it comes to access to cornea tissue, with supply often inversely proportional to burden of disease. The purpose of this review is to identify the current disparities in supply and demand of corneal donor tissue, understand how to access corneal tissue, and propose solutions that promote equitable care for patients with severe corneal disease.

Evolution of corneal transplantation techniques and their indications in a French corneal transplant unit in 2000–2020

Purpose

This retrospective cohort study assessed the evolution of corneal transplantation and its indications in the last 21 years (2000–2020) in a specialized ophthalmology department in a tertiary referral center in France.

Methods

The surgical techniques and indications, patient age and sex, and postoperative best-corrected visual acuity (BCVA) 6 months after keratoplasty were extracted.

Results

In total, 1042 eyes underwent keratoplasty in 2000–2020. Annual numbers of corneal transplantations increased by 2.2-fold. Penetrating keratoplasty (PKP) was the sole technique for the first 11 years. Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) were introduced in 2011 and 2014, respectively. Cases of both quickly increased, accounting for 28% and 41% of cases in 2015–2020, respectively. Eventually, DSAEK and DMEK were respectively used for most pseudophakic bullous keratopathy (PBK) and all Fuchs endothelial cell dystrophy (FECD) cases. PKP cases declined to 27%. Deep anterior lamellar keratoplasty (DALK) was rare (3% of all cases). These changes associated with rises in PBK and particularly FECD cases, and a strong decline in keratoconus, causing FECD, PBK, and keratoconus to move from being the 4^th, 1^st, and 3^rd most common indications to the 1^st, 2^nd, and 6^th, respectively. On average, BCVA improved by 0.1–0.3 logMAR. Patient age dropped steadily over time. Female predominance was observed.

Conclusions

The invention of DSAEK and then DMEK precipitated an enormous change in clinical practice and a large expansion of keratoplasty to new indications. This study confirms and extends previous findings in other countries.

Awareness and attitudes toward corneal donation among Canadians: informational and motivational videos can increase willingness toward corneal donation

OBJECTIVE

To assess the knowledge of corneal transplantation, willingness toward corneal donation, and the efficacy of a short informational and motivational video in increasing the willingness toward corneal donation among Canadian adults.

METHODS

Cross-sectional interventional study. A survey targeted Canadian adults, assessing their knowledge and attitude toward corneal donation and the efficacy of a 1-minute-long informative and motivational video on increasing willingness toward corneal donation.

RESULTS

The survey was accessed by 1361 individuals and 1013 completed the questionnaire (74% completion rate). The sample consisted of 36% males and 64% females, with an average age of 37.0 ± 15.3 years. The majority (58%) thought to lack basic knowledge about corneal donation. Similarly, objective knowledge of corneal donation was relatively low, with an average score of 7.8 ± 4.5 (out of 20). In our sample, 44% had not opted-in for organ donation, among whom willingness to donate one's own cornea increased from 59% pre-video to 79% post-video (relative increase of 34%; p < 0.001). Lack of awareness about the benefits of corneal donation was the most commonly cited reason for unwillingness to donate.

CONCLUSIONS

The results demonstrated a general lack of awareness of corneal donation among the Canadian population and highlighted the efficacy of a short informative and motivational video in increasing willingness to donate corneal tissue. With lack of awareness about the benefits of corneal donation being among the primary reasons for the unwillingness to donate, simple but efficacious interventions via informative and motivational videos can increase tissue donors and help reduce corneal tissue shortage.

Risk factors for keratoconus progression after treatment by accelerated cross-linking (A-CXL): A prospective 24-month study

PURPOSE

Identification of potential predictive factors for keratoconus progression after treatment by accelerated Cross-linking (A-CXL) SECONDARY OBJECTIVES: Evaluation of clinical and topographic outcomes for two years following accelerated cross-linking treatment for progressive keratoconus including: best spectacle corrected visual acuity (BSCVA), thinnest pachymetry, maximum keratometry (Kmax), cylinder.

STUDY

Prospective, interventional, monocentric study. SITE: Metz-Thionville Regional Medical Center, Lorraine University, Mercy Hospital, Metz, France.

PATIENTS AND METHODS

We included 82 eyes of 60 patients between March 2014 and June 2016 who underwent accelerated corneal cross-linking (A-CXL) with epithelial debridement for progressive keratoconus, with a minimum follow-up of 2 years. A complete clinical evaluation and corneal topography were performed before cross-linking, and subsequently at 6, 12 and 24 months post-procedure. The following parameters were monitored during follow-up: best spectacle corrected visual acuity (BSCVA), minimal pachymetry, maximum keratometry (Kmax), mean anterior and posterior curvatures, maximum posterior curvature, presence of optical aberrations, subdivided into spherical aberration, coma, astigmatism, higher order optical aberrations and residual optical aberrations. After a 2-year follow-up, two groups, defined as "responders" and "non-responders" to treatment, were separated for analysis, and their initial characteristics were compared.

RESULTS

Data for 82 eyes of 60 patients with progressive keratoconus with a mean age of 24±7 years were studied. Fourteen eyes (17.1%) showed signs of progression after treatment by A-CXL (non-responders), and 68 eyes (82.9%) showed stabilization of the disease (responders). Characteristics of non-responding eyes after A-CXL included a younger mean age (20±5 vs. 25±7 years) (P=0.04) and a lower initial mean BCVA for non-responders of 0.44±0.16 logMAR vs. 0.29±0.19 logMAR (P=0.03). Non-responders also had a higher mean maximal posterior curvature (AKB) of -10.84±1.72D vs. -9.46± 1.12D (P=0.03). They also showed more higher order optical aberrations (3.84±1.72D vs. 2.4±1.02D; P=0.01), including coma (3.85±1.81D vs. 2.1±1.01D; P=0.03) and more residual aberrations than responders (1.05±0.44D vs. 0.45±0.6D; P=0.005). No significant differences were found between responders and non-responders for the other parameters in our study.

CONCLUSION

Eyes with progressive keratoconus who did not respond to A-CXL treatment were the most aggressive cases in the youngest patients, with highest maximum corneal curvatures and most pronounced optical aberrations. These patients should be informed in advance of the high risk of non-response to A-CXL treatment, and of the potential need for additional treatment in the future.

Ophthalmic Nonsteroidal Anti-Inflammatory Drugs as a Therapy for Corneal Dystrophies Caused by SLC4A11 Mutation

Purpose

SLC4A11 is a plasma membrane protein of corneal endothelial cells. Some mutations of the SLC4A11 gene result in SLC4A11 protein misfolding and failure to mature to the plasma membrane. This gives rise to some cases of Fuchs' endothelial corneal dystrophy (FECD) and congenital hereditary endothelial dystrophy (CHED). We screened ophthalmic nonsteroidal anti-inflammatory drugs (NSAIDs) for their ability to correct SLC4A11 folding defects.

Methods

Five ophthalmic NSAIDs were tested for their therapeutic potential in some genetic corneal dystrophy patients. HEK293 cells expressing CHED and FECD-causing SLC4A11 mutants were grown on 96-well dishes in the absence or presence of NSAIDs. Ability of NSAIDs to correct mutant SLC4A11 cell-surface trafficking was assessed with a bioluminescence resonance energy transfer (BRET) assay and by confocal microscopy. The ability of mutant SLC4A11-expressing cells to mediate water flux (SLC4A11 mediates water flux across the corneal endothelial cell basolateral membrane as part of the endothelial water pump) was measured upon treatment with ophthalmic NSAIDs.

Results

BRET-assays revealed significant rescue of SLC4A11 mutants to the cell surface by 4 of 5 NSAIDs tested. The NSAIDs, diclofenac and nepafenac, were effective in moving endoplasmic reticulum-retained missense mutant SLC4A11 to the cell surface, as measured by confocal immunofluorescence. Among intracellular-retained SLC4A11 mutants, 20 of 30 had significant restoration of cell surface abundance upon treatment with diclofenac. Diclofenac restored mutant SLC4A11 water flux activity to the level of wild-type SLC4A11 in some cases.

Conclusions

These results encourage testing diclofenac eye drops as a treatment for corneal dystrophy in patients whose disease is caused by some SLC4A11 missense mutations.

New trends in corneal transplants at the University of Toronto

OBJECTIVE

To assess trends in surgical procedures and indications for all corneal transplants performed at the University of Toronto.

DESIGN

Retrospective cross-sectional study.

PARTICIPANTS

One thousand one hundred and four consecutive corneal transplants performed at the Kensington Eye Institute (KEI).

METHODS

Demographic, clinical, and pathological data retrieved from the Ophthalmic Pathology Laboratory on all corneal transplants performed at the KEI from January 2014 to December 2016.

RESULTS

Over 3 years, partial-thickness lamellar keratoplasties were performed in 880 cases (80%) while full-thickness penetrating keratoplasties (PKP) accounted for 224 cases (20%). Leading causes of corneal transplant were Fuchs' dystrophy (42%), graft failure (17%), bullous keratopathy (15%), and keratoconus (15%). Graft failure (40%) and keratoconus (31%) were the leading causes for PKP. Descemet's membrane endothelial keratoplasty (DMEK) accounted for 37% of cases, Descemet's stripping automated endothelial keratoplasty (DSAEK) for 30%, and deep anterior lamellar keratoplasty (DALK) for 13%. By 2016, partial-thickness procedures had increased by 10%, accounting for 85% of all procedures. In addition, DMEK increased by 26%, DSAEK decreased by 13%, and PKP decreased by 11%. Fuchs' dystrophy remained the leading indication for DMEK (67%) and DSAEK (42%) procedures. In 2016, 73% of DALK procedures were for the treatment of keratoconus.

CONCLUSIONS

Partial-thickness corneal transplants now account for 85% of all current graft procedures, and DMEK has emerged as the procedure of choice. Graft failure continues to be the leading indication for full-thickness grafts. Longitudinal studies are needed to determine whether these new trends persist and their future impact on graft failures.

Analysis of penetrating keratoplasty in Northern Alberta, Canada, from 2000 to 2015

OBJECTIVE

To study indications for penetrating keratoplasty (PK) at a single site. The trends in the causative organisms for infectious keratitis requiring surgery were also evaluated.

DESIGN

Retrospective observational study.

PARTICIPANTS

A total of 1181 eyes of 935 patients undergoing PK between January 2000 and December 2015 in Northern Alberta, Canada.

METHODS

Indications for PK were evaluated over the 16-year study period, and the trends in these indications were compared over 5-year intervals. The microbiology of infectious keratitis cases requiring surgery was similarly evaluated.

RESULTS

The most common indications for PK from 2000 to 2015 were keratoconus (23%), re-graft (22%), and corneal scar (12%). There was a decline in the percent of total surgeries done for Fuchs' dystrophy (p = 1.1 × 10^-3) and pseudophakic bullous keratopathy (p = 5.6 × 10^-5), whereas a corresponding increase in keratoconus (p = 3.2 × 10^-5), trauma (p = 2.1 × 10^-3), and infectious keratitis cases (p = 0.010) was observed. The most common causes for infectious keratitis cases were viral (45%), bacterial (18%), parasitic (11%), and fungal (9%). There was a significant increase in the percent of infectious keratitis cases due to a viral etiology from 2005 to 2010 (p = 6.4 × 10^-3).

CONCLUSIONS

The indications for PK are comparable with other centres in North America. Nearly half of all infectious keratitis cases requiring surgery are viral. The increase in viral cases requiring surgery may reflect improved diagnostics or recurrent cases.

An 11-Year Review of Keratoplasty in a Tertiary Referral Center in Turkey: Changing Surgical Techniques for Similar Indications

OBJECTIVES

Study aims to evaluate the indications and surgical techniques for corneal transplantation and to report changes in trends for preferred keratoplasty surgical techniques.

METHODS

Clinical records of 815 consecutive corneal transplantations between January 1, 2004 and December 31, 2014 in Haydarpasa Numune Training and Research Hospital Eye Clinic were analyzed and classified into seven broad groups according to indications. Main outcome measures were change of leading indications and trends for surgical techniques.

RESULTS

Leading indications for keratoplasty were keratoconus (KCN) (27.7%), bullous keratopathy (BK) (23%), postinfectious corneal scars (13.5%), regrafts (13.1%), corneal dystrophies (12.1%), and noninfectious corneal scars (5.4%). Regrafts were the only indication with a significantly increasing trend (P<0.01). Since the introduction of lamellar keratoplasty (LK) techniques including deep anterior lamellar keratoplasty (DALK) and Descemet stripping automated endothelial keratoplasty (DSAEK), there was a significant increasing trend in number and percentage of both LK techniques (DALK; P=0.001 and P=0.007, and DSAEK; P<0.001 and P<0.001, respectively) and a significant corresponding decline in the percentage of penetrating keratoplasty (PK) (P<0.01). Similarly, DALK and DSAEK replaced PK as the preferred surgical technique for KCN and BK indications, (P=0.007 and P=0.01, respectively). Although PK was the most common surgical technique over the 11-year period (54.7%), both anterior and posterior LK techniques showed an emerging trend as the procedures of choice when indicated.

CONCLUSIONS

No major shift was observed in the clinical indications for corneal transplantation over the previous 11 years, except for regrafts. Lamellar keratoplasty techniques largely overtook the PK technique, but PK was still the overall preferred technique in the era when both LK techniques were used.

The Evolution of Corneal Transplantation

Background

The aim of this study was to investigate the evolution of surgical methods in and leading indications for corneal transplantation from 2005 to 2016.

Material/Methods

Data from the corneal graft waiting list and from all keratoplasties carried out between 2005 and 2016 at the University Eye Hospital Tübingen were retrospectively evaluated.

Results

A total of 1259 keratoplasties were performed between 2005 and 2016 at the University Eye Hospital Tübingen. The most common surgical indications for corneal transplantation were Fuchs endothelial corneal dystrophy (45.5%) and keratoconus (14.2%). The mean rate of corneal transplantations almost doubled from 71 keratoplasties per year in the first 6-year period to 139 keratoplasties per year in the second 6-year period (P=0.005). The number of penetrating keratoplasties remained similar. The number of Descemet membrane endothelial keratoplasties (DMEK) increased significantly from 2008 to 2016 (P<0.0001). One DMEK procedure was performed in 2008 (representing 1.4% of all transplantations), while 75 DMEK procedures were performed in 2016 (representing 60.5% of all transplantations) (P<0.0001). DMEK became the favored surgical method for endothelial disorders, exceeding penetrating keratoplasty in 2013.

Conclusions

Our study shows evolutionary changes in preferred corneal transplantation techniques and leading indications for keratoplasty from 2005 to 2016. Since its introduction a decade ago, DMEK is currently the golden standard in the management of corneal endothelial dysfunction.

Clinical and epidemiological aspects of cornea transplant patients of a reference hospital

Objective:

clinically characterizing cornea transplant patients and their distribution according to indicated and post-operative conditions of cornea transplantation, as well as estimating the average waiting time.

Method:

a cross-sectional, descriptive and analytical study performed for all cornea transplants performed at a reference service (n=258). Data were analyzed using Statistical Package for the Social Sciences, version 20.0.

Results:

the main indicator for cornea transplant was keratoconus. The mean waiting time for the transplant was approximately 5 months and 3 weeks for elective transplants and 9 days for urgent cases. An association between the type of corneal disorder with gender, age, previous surgery, eye classification, glaucoma and anterior graft failure were found.

Conclusion:

keratoconus was the main indicator for cornea transplant. Factors such as age, previous corneal graft failure (retransplantation), glaucoma, cases of surgeries prior to cornea transplant (especially cataract surgery) may be related to the onset corneal endothelium disorders.

Current indications and surgical approaches to corneal transplants at the University of Toronto: A clinical-pathological study

OBJECTIVE

To determine the most common reasons and surgical approaches for corneal graft surgery at the Kensington Eye Institute (KEI), University of Toronto.

DESIGN

Retrospective cross-sectional study.

PARTICIPANTS

A total of 229 consecutive corneal transplants performed at the KEI.

METHODS

Demographic, clinical, and pathological data on all 2012 and 2013 corneal transplants were collected.

RESULTS

The mean age for corneal transplants was 65 ± 16 years; 39% were full-thickness penetrating keratoplasties (PK) and 61% were partial-thickness. Graft failure (30%), infection (18%), and keratoconus (17%) were the leading indications for PK. Fuchs' dystrophy (40%) and bullous keratopathy (24%) were main causes for partial-thickness procedures. Among partial-thickness approaches, Descemet's stripping automated endothelial keratoplasty (DSAEK), deep anterior lamellar keratoplasty (DALK), and Descemet's membrane endothelial keratoplasty (DMEK) procedures accounted for 68%, 16%, and 16%, respectively. Fuchs' dystrophy (40%) and bullous keratopathy (33%) were the most common indications for DSAEK. Keratoconus (57%) and corneal scarring (35%) were the most common indications for DALK, whereas Fuchs' dystrophy (82%) accounted for most DMEK procedures. The most common reasons for all corneal grafts were Fuchs' dystrophy (25%), bullous keratopathy (21%), graft failure (17%), and keratoconus (12%).

CONCLUSIONS

Almost two-thirds of all corneal transplant procedures at the University of Toronto are partial thickness procedures. A failed graft was found to be the most common indication for full-thickness transplants. Fuchs' dystrophy was the most common indication for a partial-thickness approach, most often treated by DSAEK. Longitudinal data are needed to determine whether partial-thickness surgeries will improve graft survival and reduce the need for regraft.

Suitability of Corneal Tissue for Transplantation Derived From Violent Death: A 10-Year Analysis

Trauma is a leading cause of death and disability worldwide. Corneal tissue donors generally are those who suffered an injury to the brain or fatal trauma caused by stroke, vehicle/motorbike accidents, gunshot wounds, and drowning or cardiovascular death. In Brazil, the Distrito Federal (DF) Eye Bank, located within a trauma center hospital, and the Secretariat of Public Security have collaborated with the aim of increasing the overall number of cornea donations from fatal trauma victims. The purpose of this study was to determine the suitability of cornea tissue for transplantation derived from trauma-related death. The records of eyes donated in the DF Eye Bank were analyzed retrospectively for the period from 2004-2013. We had 3388 cornea donors, the majority of which were between 21 and 30 years old (17.4%), which were derived from violent death (84.1%; P = .00) and were predominately male (73.5%). Among the donated corneas, 54.0% were used for optic purposes. Mechanical trauma caused by gunshot, stabbing or blunt force (23.7%), and road traffic injuries (11%) were the main causes of violent death. Another common cause of death was cardiovascular disease (26.3%). Donor tissue derived from violent death had no statistical interference on tissue suitability for transplantation (P = .06). Because of the large waiting lists, and waiting times for transplants, it is advisable to increase the available tissue from corneas donors derived from violent death through the implementation of this interagency model of collaboration and by the practicing of active tissue donor screening in trauma center hospitals.