Descemet Membrane Endothelial Keratoplasty in Congenital Hereditary Endothelial Dystrophy: Initial Experiences

Pediatric Corneal Transplantation in Uyo, Nigeria: Early Experiences

ABSTRACT

The burden of avoidable blindness from corneal disease is significantly higher where access to specialist eye care, the cost of treatment and the treatment infrastructure including eye banking, are beyond the reach of the impoverished masses. Corneal transplantation in children is challenging: it is more technically complex; patients often require multiple examinations under general anaesthesia to optimize treatment outcomes. There is also the increased risk of several complications including graft dehiscence, infection, rejection, and inappropriate patient or caregiver care. However, when successful, it restores vision. We present a report of our initial experience with penetrating keratoplasty in 2 children with blinding corneal disease in Uyo, Nigeria. Corneal transplantation history was retrieved and data (including data on age, sex, aetiology of corneal disease, indications for corneal transplantation, pre-operative and post-operative visual acuity and intraocular pressure measurements) was extracted for this report. Both patients had standard penetrating keratoplasty performed by one surgeon, under general anaesthesia. Case one was a 10-year-old male presenting with profound visual impairment from congenital hereditary endothelial dystrophy. His best corrected post-operative visual acuity was 6/24. Case two was a 3-year-old male with vision loss due to a corneal leucoma following treated herpes simplex keratitis. Post-operatively, his best corrected visual acuity improved to 6/12. Corneal graft tissue remained clear at more than 3 years of follow-up. Although amblyopia was a notable co-morbidity, corneal transplantation significantly improved their vision. Corneal banking services are advocated for in resource-limited settings where the magnitude of corneal blindness is greatest.

Novel Proposed Algorithm in Congenital Hereditary Endothelial Dystrophy

PURPOSE

Congenital hereditary endothelial dystrophy (CHED) is a rare, autosomal recessive, monogenic corneal condition with variable expressivity. Often presents in bilateral symmetrical progressive corneal cloudiness that starts in the early infancy. It is characterized by increased corneal thickness, profound corneal edema, and thickening of the Descemet membrane due to endothelial dysfunction. The published literature lacks uniform guidelines for grading corneal cloudiness and management algorithm for CHED cases. This article focuses on applying newer investigational modalities to fine-tune surgical outcomes and more recent CHED management strategies.

METHODS

This comprehensive literature review was performed based on a search on the PubMed database of relevant CHED articles focusing on those published in the last 7 years. A total of around 70 articles were reviewed, and 17 of them were included in this review. These include systemic reviews, randomized controlled clinical trials, cohort studies, case-controlled studies, and case series.

RESULTS

Corneal cloudiness grading in CHED using subjective and objective methods using Anterior Segment Optical Coherence Tomography (AS-OCT) and densitometry using Scheimpflug imaging can help select appropriate management plan for CHED cases. DSAEK outscores penetrating keratoplasty with much fewer complications and expedites visual recovery, which helps mitigate amblyopia.

CONCLUSION

Managing cases of CHED has been a challenge due to the dilemma in timing and appropriate surgical method selection and lack of definitive medical or other conservative approaches. Currently, DSAEK has shown favorable results in cases of CHED. However, appropriate staging of CHED and selecting the appropriate management approach appears to play a critical role in managing such cases. Besides these, novel treatment modalities such as nonsteroidal anti-inflammatory agents (NSAIDS) that target restoring water-flux activity in subtype of CHED and gene editing using CRISPR-Cas9 are promising paradigm treatment modalities.

Risk Factors for Descemet Membrane Endothelial Keratoplasty Rejection: Current Perspectives- Systematic Review

Descemet membrane endothelial keratoplasty (DMEK) is a corneal endothelial transplantation procedure with selective removal of a patient's defective Descemet membrane and endothelium. It is replaced with a healthy donor Descemet membrane and endothelium without a stromal component. Corneal graft rejection can be at the level of epithelium, stroma as well endothelium. DMEK graft rejection is relatively less common than rejection with DSAEK or penetrating keratoplasty, and a good outcome may be achieved with prompt management. The clinical picture of DMEK rejection is usually similar to endothelial rejection in Descemet Stripping Endothelial Keratoplasty (DSEK/DSAEK), which generally manifests as pain, redness, reduction in visual acuity, stromal edema, endothelial rejection line, keratic precipitates at the back of the cornea and corneal neovascularization. However, more subtle forms of rejection or immune reactions are more common in DMEK compared to DSAEK eyes. Early clinical diagnosis, prompt intervention, and meticulous management safeguard visual acuity and graft survival in these cases. Intensive topical steroids form the mainstay in the management of DMEK rejection. Sometimes, oral or intravenous steroids or other systemic immunomodulators may be required. DMEK graft failure can be primary or secondary, and failure usually requires a second procedure in the form of repeat DMEK or DSEK or penetrating keratoplasty (PKP). A detailed literature search was performed using search engines such as Google Scholar, PubMed, and Google books, and a comprehensive review on DMEK rejection was found to be lacking. This review is a comprehensive update on the risk factors, pathophysiology, primary and secondary graft failure, recent advances in diagnosis, prevention of rejection, and updates in the management of DMEK rejection. The review also discusses the differential diagnosis of DMEK failure and rejection, prognosis, and future perspectives considering DMEK failure and rejection.

10-year experience with lamellar keratoplasty for the surgical Management of Paediatric Corneal Diseases

PURPOSE

To evaluate the outcomes of various lamellar keratoplasty techniques performed at our Institution in children aged 14 years or younger over the last decade.

METHODS

This single-centre study reviewed 72 eyes that underwent lamellar keratoplasty for various indications. Deep anterior lamellar keratoplasty (DALK) was performed in 19 eyes, mushroom penetrating keratoplasty (PK) in 27 eyes and Descemet stripping automated endothelial keratoplasty (DSAEK) in 25 eyes. The main outcome measures included best spectacle-corrected visual acuity (BSCVA), complications and rate of graft failure which was defined as any graft requiring repeat transplantation.

RESULTS

Best spectacle-corrected visual acuity (BSCVA) significantly improved after DALK, mushroom PK and DSAEK (all p < 0.05), with 50%, 60% and 56% of eyes reaching ≥20/40, respectively. Stromal rejection was observed in 1 eye (5.3%) after DALK, whilst endothelial rejection occurred in 1 eye after mushroom PK (3.7%) and 1 eye after DSAEK (4.0%). Overall survival was 100% after DALK (mean follow-up: 23.0 months), 92.8% after mushroom PK (mean follow-up: 42.3 months) and 96.0% after DSAEK (mean follow-up: 33.6 months).

CONCLUSION

Deep anterior lamellar keratoplasty (DALK), mushroom PK and DSAEK offer good visual outcomes for children with corneal pathology, with low rates of immunological rejection and graft failure.