Endothelial keratoplasty for posterior polymorphous corneal dystrophy in a 4-month-old infant

Pediatric corneal transplantation: techniques, challenges, and outcomes

Pediatric corneal transplant is a highly demanding and technically challenging procedure for the cornea surgeon in today's era. These cases pose unique challenges in clinical and surgical management. The indications of pediatric corneal transplant can be therapeutic, tectonic, optical, and cosmetic. Pediatric patients undergoing corneal transplants are at a high risk of graft infection, failure, rejection, dehiscence, and amblyopia due to young age, robust immune system, increased incidence of trauma, and compliance issues. The other factors contributing to graft failure can be allograft rejection, secondary glaucoma, corneal vascularization, multiple surgeries, vitreous prolapse, and lack of treatment compliance. A successful corneal transplant in children depends on meticulous preoperative evaluation, uneventful surgery, the expertise of a corneal surgeon, and regular and timely postoperative follow-up. Therapeutic and optical penetrating keratoplasty are the most commonly performed transplants in children. However, with the advancements in surgical technique and management protocol, the current focus has shifted toward lamellar keratoplasty. Lamellar keratoplasty offers early visual recovery and potentially fewer complications. Visual rehabilitation through corneal transplant in otherwise blind eyes can be a boon for the children. Recently, keratoprostheses have been promising in children with multiple graft failures. The current review gives insights into epidemiology, etiology, indications, clinical characteristics, investigations, management options, recent advances, and the future of pediatric corneal transplants. As surgical techniques continue to grow and comprehension of pediatric corneal transplants is improving, we can safeguard these eyes with the best possible anatomical and functional outcomes.

A review of techniques and outcomes of endothelial keratoplasty in congenital hereditary endothelial dystrophy

Congenital hereditary endothelial dystrophy affects the Descemet membrane and endothelium, resulting in corneal decompensation. Penetrating keratoplasty (PKP) has been the gold-standard surgical management until recently; however, at present, endothelial keratoplasty (DSEK/DSAEK/n-DSEK: Descemet-stripping or non-Descemet stripping endothelial keratoplasty and DMEK/n-DMEK: Descemet membrane endothelial keratoplasty) is being preferred due to lesser intraoperative and postoperative complications, early visual recovery, and comparable visual outcomes. Endothelial keratoplasty (EK) can be challenging, especially in pediatric eyes with CHED due to smaller eyeballs, shallow anterior chambers, phakic status, and poor intraoperative visibility due to thick and hazy corneas. A total of 198 articles matched our search strategy. After screening for duplication and going through the titles and abstracts, 12 relevant original articles, one case series, and six case reports were included in this review. Various surgical modifications have to be adopted in comparison to adult eyes to overcome the aforementioned difficulties. Regardless, studies have shown favorable visual outcomes with better graft survival and fewer complications in eyes that underwent EK compared to PKP. Hence, timely surgical intervention and strict amblyopia management can result in better final visual outcomes. The purpose of this review is to summarize various intraoperative difficulties and the surgical modifications required, different surgical techniques, visual and graft-related outcomes, and various complications of EK in CHED eyes.

Descemet Membrane Endothelial Keratoplasty (DMEK) for Severe Verrucous Posterior Polymorphous Corneal Dystrophy with Uncommon Clinical and Ultrastructural Findings

PURPOSE

To report a case of severe verrucous posterior polymorphous corneal dystrophy (PPCD) and cataract, which was treated with Descemet membrane endothelial keratoplasty (DMEK) and simultaneous cataract surgery as a triple procedure (Triple-DMEK).

METHODS

A 62-year-old female patient presented to our department for co-evaluation of advanced PPCD with cataract and progressive light sensitivity in both eyes. The clinical examination demonstrated unusual clinical findings with prominent verrucous lesions on the posterior surface of the cornea without corneal decompensation. We performed a Triple-DMEK in case of simultaneous cataract. The corneal tissue was examined by light and transmission electron microscopy.

RESULTS

Intraoperatively, it was difficult to remove the verrucous structures completely after classical descemetorhexis. Light microscopic examination demonstrated epithelium-like transformation of the corneal endothelium by immunostaining (cytokeratin AE1/3 staining). Transmission electron microscopy revealed thickening of Descemet's membrane (18.5 to 30.0 µm). The anterior banded layer had a normal structure and was slightly thickened (3.5 to 5.5 µm). A normal posterior non-banded layer (PNBL) was observed but thinned (2.5 to 4.0 µm) or missing. It was followed by an altered PNBL with abnormal fibrillary inclusions, which was strongly and variably thickened (11.0 to 24.5 µm). The corneal endothelium was degenerated, partially absent, and epithelial-like altered. The nodular lesions were found to consist of a few degenerated cells that were embedded in an amorphous extracellular matrix interspersed with collagen fibers, which were not arranged in regular lamellae, forming the corneal stroma. The occurrence of pigment granules among the cellular debris suggested that the cells were endothelial cells. The corrected distance visual acuity improved from 20/50 to 20/30 in the right eye (+ 0.00/- 1.75/157°) and from 20/60 to 20/30 in the left eye (+ 0.00/- 1.75/33°), with significant improvement in light sensitivity.

CONCLUSION

The clinical and ultrastructural findings seem to be an unusual variant of the typical characteristic appearance of a PPCD. This case demonstrates that Triple-DMEK is feasible even in very advanced dystrophic changes of the posterior corneal surface, with good morphological and functional results.

Update on Pediatric Corneal Diseases and Keratoplasty

Managing pediatric corneal disorders is challenging as the prognosis of pediatric keratoplasty depends on several factors. Advancements in the genetic basis of congenital corneal diseases and investigations in congenital corneal conditions provide a better understanding of pediatric corneal conditions. Surgeons performing keratoplasty in children now have a choice of various techniques. Evolving surgical techniques of anterior lamellar and endothelial keratoplasties has expanded the management interventions in these pediatric corneal morbidity conditions; however, considerable concerns still exist in association with corneal transplantation in infants and children. Outcomes in pediatric keratoplasty depend upon the preoperative indications, the timing of surgical intervention, intraoperative and postoperative factors including the patient/care givers' compliance. Factors such as low scleral rigidity, higher rate of graft failure, need for frequent examinations under anesthesia, and difficulty in optimal visual acuity assessment still remain a considerable challenge in pediatric scenarios. In children, deprivation amblyopia as a result of the corneal opacification can adversely affect visual development, causing dense amblyopia. Outcomes to surgical interventions for management of corneal opacification in children is further compromised by the pre-existing amblyopia apart from the concerns of refractive outcome of the graft. Graft rejection, graft infection, amblyopia, and glaucoma continue to be serious concerns. In recent years both anterior and posterior lamellar keratoplasty techniques are being increasingly performed in pediatric eyes, which offer advantages in the form of lower risk of graft rejection. The timing of surgery, careful case selection, cautious intraoperative approach, and optimal postoperative management can improve the anatomical and functional outcome in difficult cases.

Bilateral posterior lamellar corneal transplant surgery in an infant of 17 weeks old: Surgical challenges and the added value of intraoperative optical coherence tomography

This study aimed to describe the surgical challenges, management, and value of intraoperative optical coherence tomography in a case of a bilateral Descemet Stripping Automated Endothelial Keratoplasty corneal transplantation at 17 weeks of age for the treatment of severe posterior polymorphous corneal dystrophy resulting from a de novo mutation of the OVOL2‐gene.

Pediatric endothelial keratoplasty: a systematic review and individual participant data meta-analysis

BACKGROUND

Recently, endothelial keratoplasty (EK) has been increasingly considered the first intervention in pediatrics with isolated corneal endothelial dysfunction. This systematic review aims to investigate the current evidence about the advantages, disadvantages, technical challenges, and clinical outcomes of EK in the pediatric group.

METHOD

All the English literature relevant to pediatric EK was searched in PubMed, Embase, Scopus, and Cochrane databases with appropriate keywords. Relevant data were pooled to conduct an individual participant data meta-analysis.

RESULTS

Of 1646 articles found initially, 35 articles were finally eligible to be included in our study. A total of 154 eyes of 107 patients underwent Descemet's stripping automated endothelial keratoplasty (DSAEK). Congenital hereditary endothelial dystrophy (CHED) was the most reported indication for pediatric DSAEK (108 eyes). Descemet's membrane endothelial keratoplasty (DMEK) was performed in 2 eyes of 2 cases, one with PPCD and another one in a patient with Kearns-Sayre syndrome. Owing to some specific anatomical and physiological pediatric characteristics, some modifications in a standard procedure were suggested. The average follow-up period was 23.80 ± 20.18 months (3 months to 8.5 years). Seventy-six eyes who had a mean best-corrected visual acuity (BCVA) of 1.36 ± 0.70 (0.49 to 3) logMAR preoperatively found mean BCVA of 0.51 ± 0.33 (0.04 to 2) logMAR postoperatively. Graft dislocation was the most reported complication (26 eyes). The rate of other complications was low. Endothelial cell loss was reported from 8.3 to 63.7% after pediatric EK with follow-up duration from 3 months to 8.3 years.

CONCLUSION

EK procedures, despite some technical challenges, are feasible surgical techniques with acceptable visual and anatomical outcomes in the management of pediatrics with corneal endothelial dysfunction and minimal stromal involvement.

Pediatric Descemet Membrane Endothelial Keratoplasty

PURPOSE

To report the technique and outcome of Descemet membrane endothelial keratoplasty (DMEK) in pediatric patients older than 6 years of age.

DESIGN

Institutional interventional retrospective case series.

METHODS

This study included 5 eyes of patients less than 15 years of age with endothelial dysfunction who underwent DMEK. Three eyes had Descemet stripping done of the same size as the donor graft. Two eyes underwent non-Descemet stripping endothelial keratoplasty. Attachment of DMEK scroll and improvement in corneal clarity, vision, pachymetry, and intraoperative or postoperative complication was noted. We defined primary graft failure as nonclearing corneal edema despite a well-attached lenticule on anterior segment optical coherence tomography.

RESULTS

A total of 5 eyes of 5 children (all male) with a mean (± standard deviation) age of 9.2 ± 3.42 years underwent DMEK. The mean preoperative visual acuity of 1.93 ± 0.25 logMAR units improved postoperatively to 0.98 ± 0.29 (95% confidence interval, P = .03). Anatomic success (well-attached scroll with a more transparent cornea with a decrease in pachymetry) was seen in 4 of 5 eyes (80%). One eye had a primary donor failure. Two out of the 5 eyes (40%) required rebubbling. The mean pachymetry in eyes with successful procedure reduced from 1094.5 ± 101.5 µm to 619.25 ± 150.3 µm (P = .03).

CONCLUSIONS

Although DMEK in pediatric eyes is challenging, the early results are encouraging, and it is a viable option in pediatric patients with endothelial failure.

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

PURPOSE

To report our early experiences with Descemet membrane endothelial keratoplasty (DMEK) in congenital hereditary endothelial dystrophy (CHED).

METHODS

Retrospective analysis of medical records of eyes with CHED that underwent DMEK between January 1, 2018, and April 30, 2019, and had a minimum of 1-year follow-up.

RESULTS

Three eyes of 2 CHED patients (a 10-year-old girl and a 22-year-old man) were included. Both had decreased vision and hazy corneas from birth and underwent DMEK during the study period. Surgery was performed by a single surgeon and was uneventful in all 3 eyes. Within 1 month of surgery, the corneal edema cleared, and vision improved significantly. The mean decimal visual acuity improved from 0.15 ± 0.08 (baseline) to 0.33 ± 0.19 at 3 months. The mean central corneal thickness improved from 928 ± 2.3 μm (baseline) to 555.3 ± 25.8 μm at 3 months. The final visual outcome was less in 1 eye because of dense amblyopia. In all 3 eyes, a subtle stromal haze persisted even after resolution of edema. One eye had graft rejection 7 months after surgery because of discontinuation of medications, effectively managed by increasing the frequency of topical steroids.

CONCLUSIONS

DMEK may be a viable option in phakic eyes with CHED.

Endothelial cell density in children with posterior polymorphous corneal dystrophy: a longitudinal case-control study

OBJECTIVE

To evaluate longitudinal endothelial cell characteristics of children with posterior polymorphous corneal dystrophy (PPCD).

METHODS

In this prospective case-control study, children with PPCD were followed with slit-lamp photography and non-contact specular microscopy. Patient's eyes were subdivided according to the clinical subtypes of PPCD (vesicular, band, diffuse, and unaffected) and the number of lesions present on the posterior corneal surface. Findings were then compared with age-matched controls.

RESULTS

Thirty eyes of 15 patients with PPCD with a mean age 10.5 ± 3.1 years were analysed. Mean follow-up was 3.0 ± 1.0 years. PPCD morphology was vesicular in 40%, diffuse in 37%, band type in 10% and 13% had no detectable lesions despite contralateral involvement. Fourteen eyes (47%) had ≥5 endothelial lesions. Patients with PPCD had significantly lower endothelial cell densities (ECD) at recruitment (1918.9 ± 666.3 vs. 3340.1 ± 286.5 cells/mm², p < 0.007) and at final follow-up (1793.1 ± 684.6 vs. 3265.2 ± 304.3 cells/mm², p < 0.007) compared to age-matched controls. The lowest ECDs were found in eyes with diffuse type PPCD and those with ≥5 posterior corneal lesions, while clinically unaffected eyes in patients with confirmed PPCD in fellow eye had a normal ECD. However, the rates of annual ECD decline were not significantly different between eyes with PPCD in general, between the subgroups of PPCD and the normative groups.

CONCLUSION

Endothelial cell density is significantly reduced among children with PPCD and depends on the clinical subtype and the number of posterior corneal lesions present. However, annual ECD loss is similar between normal eyes and those with PPCD.

Outcomes of Descemet's membrane endothelial keratoplasty for congenital hereditary endothelial dystrophy

PURPOSE

To report outcomes of Descemet's membrane endothelial keratoplasty (DMEK) in eyes with congenital hereditary endothelial dystrophy (CHED).

METHODS

The medical records of patients with CHED who underwent DMEK were retrospectively reviewed. Pre- and postoperative visual acuity, corneal thickness, corneal clarity, and graft survival, were analyzed, and intra- and postoperative complications were assessed.

RESULTS

A total of 14 eyes of 8 patients were included. Surgery was performed at a mean age of 10 ± 7 years (range, 2-23). DMEK was successfully performed in all eyes, with 13 of 14 eyes (93%) maintaining a clear cornea at final follow-up (mean, 16.9 ± 8.1 months). Following surgery, corrected distance visual acuity improved from 0.9 ± 0.3 logMAR (Snellen 20/158) to 0.4 ± 0.2 (20/50), and pachymetry improved from 932 ± 57 μm to 642 ± 93 μm. Endothelial cell loss was 33%, and average cell counts were 1767 ± 281 cells/mm² at final follow-up. Intraoperative aqueous misdirection occurred in both eyes of a 2-year-old child, requiring pars plana vitrectomy. Postoperative donor Descemet's membrane detachment occurred in 4 eyes. Rebubbling was performed in 3 eyes (21%); 1 eye had spontaneous reattachment. One eye (8%) had possible graft failure during follow-up, requiring repeat DMEK surgery.

CONCLUSIONS

In our study cohort of eyes with CHED, DMEK was performed with good visual outcome. Rebubbling was necessary for donor reattachment in the early postoperative period in some cases.

Corneal Folds After Descemet Membrane Endothelial Keratoplasty in Congenital Hereditary Endotheial Dystrophy

PURPOSE

To report a new clinical sign of corneal folds after Descemet membrane endothelial keratoplasty (DMEK) in the eyes with congenital hereditary endothelial dystrophy (CHED).

METHODS

Retrospective review of cases of CHED who presented with unusual folds in recipient cornea after the DMEK procedure for CHED. Clinical outcomes including visual acuity, pachymetry, specular microscopy, anterior segment optical coherence tomography, and corneal clarity, besides postoperative complications were analyzed.

RESULTS

Fifteen eyes of 11 cases of CHED successfully underwent DMEK. Five eyes of 4 patients, mean age 17.2 ± 5.8 years (range 10-23 years), developed unusual folds in the anterior cornea after resolution of stromal edema. Mean follow-up was 7.8 ± 2.5 months (range 6-12 months). Mean best spectacle-corrected visual acuity improved from 0.8 ± 0.3 LogMAR preoperatively to 0.3 ± 0.2 LogMAR postoperatively. Corneal thickness improved from 991 ± 65 μm (range 924-1088 μm) preoperatively to 595 ± 78 μm postoperatively (range 525-730 μm). Average endothelial cell counts were 1708 ± 271 cell/mm2 at the last follow-up. No intraoperative or postoperative complications were reported. The corneal folds remained unchanged during the follow-up. Comparative analysis with remaining 10 eyes did not show any significant differences.

CONCLUSIONS

Cornea can present with unusual folds in the anterior stroma after successful DMEK in CHED. These folds may possibly be due to difference in collagen structure between anterior and posterior corneal stroma and needs to be studied further.

Successful pediatric DMEK facilitated by intracameral tissue plasminogen activator to mitigate anterior chamber fibrin reaction

Purpose

To report a case of a successful Descemet's membrane endothelial keratoplasty (DMEK) facilitated by the use of intracameral tissue plasminogen activator (tPA) in a 4-year old with posterior polymorphous corneal dystrophy (PPCD).

Observations

A 4-year old male was referred for bilateral corneal haze and blurry vision. Patient's exam and genetic testing were consistent with a diagnosis of PPCD. Patient was successfully treated with DMEK augmented by the use of intracameral tPA intraoperatively to combat the anterior chamber fibrin formation that can occur in DMEK.

Conclusions

To our knowledge, this case represents the youngest reported successful DMEK procedure and the first case describing the use of intracameral tPA intraoperatively to attenuate the anterior chamber fibrin formation that can occur in DMEK.