Lamellar keratoplasty in children

Myeloid-derived suppressor cells ameliorate corneal alkali burn through IL-10-dependent anti-inflammatory properties

This study aims to investigate the efficiency and the underlying mechanism of myeloid-derived suppressor cells (MDSCs) in corneal alkali burns (CAB). In the study, CD11b+ Gr-1+ cells from C57BL/6J mice bone marrow were cultured and induced. Cell activity and immunoregulatory function were assessed by flow cytometry in vitro. The optimal strategy of MDSCs therapy was assessed by slit-lamp microscopy, and flow cytometry in vivo. The therapeutic effects of MDSCs and the critical signaling pathway were investigated by hematoxylin-eosin (HE) staining, slit-lamp microscopy, flow cytometry, and immunofluorescence. The expression level of the NLRP3 inflammasome pathway was examined. The crucial biochemical parameters of MDSCs were examined by RNA-seq and qPCR to screen out the key regulators. The mechanism of MDSCs' therapeutic effects was explored using MDSCs with IL-10 knockout/rescue by slit-lamp microscopy, HE staining, and qPCR evaluation. The cell frequencies of macrophages and neutrophils in the cornea were examined by flow cytometry in vivo. The results demonstrated that the induced MDSCs meet the standard of phenotypic and functional characteristics. The treatment of 5 × 105 MDSCs conjunctival injection on alternate days significantly ameliorated the disease development, downregulated the NLRP3 inflammasome pathway, and decreased the cell frequencies of macrophages and neutrophils in vivo significantly. IL-10 was screened out to be the critical factor for MDSCs therapy. The therapeutic effects of MDSCs were impaired largely by IL-10 knock-out and saved by the IL-10 supplement. In conclusion, MDSCs therapy is a promising therapeutic solution for CAB. MDSCs fulfilled immunoregulatory roles for CAB by IL-10-dependent anti-inflammatory properties.

Updates on congenital hereditary endothelial dystrophy

Congenital hereditary endothelial dystrophy (CHED) is a rare genetic corneal disorder causing progressive cornea clouding and significant visual impairment. CHED remains a leading indication for pediatric corneal transplantation despite its infrequency, particularly in regions with high consanguinity rates like Southeast Asia. Identifying the Solute Carrier Family 4 Member 11 (SLC4A11) gene as the genetic basis of CHED has led to the discovery of it's various genetic variations. However, a comprehensive understanding of its clinical-genetic correlation, pathophysiology, and optimal management is ongoing. This review aims to consolidate current knowledge about CHED, covering its genetic origins, pathophysiological mechanisms, clinical presentation, and management strategies. Surgical intervention, such as penetrating keratoplasty (PK), Descemet stripping automated endothelial keratoplasty (DSAEK), and Descemet membrane endothelial keratoplasty (DMEK), remains the primary treatment. DSAEK and DMEK offer advantages over PK, including quicker visual recovery, reduced complications, and longer graft survival, especially in the pediatric age group. The timing of surgical interventions depends on disease severity, age at presentation, comorbidities, and visual potential. Elevated oxidative stress in CHED corneal tissue suggests potential benefits from anti-inflammatory drugs to rescue mutated endothelial cells. Considering the limitations of corneal graft surgeries, exploring novel gene-based molecular therapies are essential for future management. Early diagnosis, appropriate surgical interventions, amblyopia control, and genetic counseling for predictive analysis are pivotal for optimizing CHED management. A multidisciplinary approach involving ophthalmologists, researchers, and genetic counselors is essential for precise diagnosis and optimal care for CHED patients.

[Corneal disease in childhood-Hereditary, degenerative or infectious?]

BACKGROUND

Adequate visual acuity significantly contributes to the age-appropriate development of children's neurobehavior. Infantile corneal opacities are rare but implicate a high potential for amblyopia.

OBJECTIVE

This review aims to provide an overview of the most common causes of infantile corneal opacities and highlights ophthalmopathological correlations.

METHODS

The following review is based on an extensive literature search.

RESULTS

If metabolic diseases, traumatic or infectious events can be excluded as a cause for an infantile corneal opacity, it is important to focus on the 3Ds, corneal dysgenesis, corneal dystrophy or corneal degeneration.

DISCUSSION

If corneal opacities occur in childhood, early recognition, diagnosis, and initiation of treatment, including prophylaxis of amblyopia, are of utmost importance. In unexplained corneal opacities the histopathological work-up of the explanted cornea can contribute to the final diagnosis.

Outcomes of Corneal Transplant in Childhood Glaucoma

PRCIS

Childhood glaucoma produces alterations in the postnatal development and function of various ocular structures, including the cornea. Childhood glaucoma patients present lower corneal transplant survival rates. Our series shows outcomes of corneal transplant in childhood glaucoma with survival rates of 29% at 2 years.

OBJECTIVE

To investigate the surgical outcome of different types of keratoplasty in eyes with childhood glaucoma.

PATIENTS AND METHODS

A retrospective review was made of the medical records from 17 eyes of 15 patients who were diagnosed with childhood glaucoma and received a corneal transplantation between January 2010 and July 2020. Patient demographics, intraocular pressure, previous ocular surgery, comorbidities, corneal transplant surgery, and follow-up outcome were collected. The primary efficacy endpoint was graft survival (in months) until failure, the latter being considered as irreversible loss of corneal transparency. Secondary efficacy points were the need for an increase in topical hypotensive therapy and the need for additional surgery.

RESULTS

Seventeen eyes of 15 patients were included, 11 eyes (10 patients) with primary congenital glaucoma and 6 with other types of childhood glaucoma. Corneal transplantation was performed at the mean age of 23.76 ± 14.86 years. At the time of the transplantation, the number of topical medications was 1.35 ± 1.27, intraocular pressure was 15.00 ± 8.34 mm Hg, and patients had received up to 7 glaucoma surgeries. Descemet stripping automated endothelial keratoplasty was performed in 13 eyes (76%) and penetrating keratoplasty in 4 (24%). After surgery, 7 (41%) eyes required increased topical treatment and 2 (12%) glaucoma surgery. Twelve eyes (71%) developed graft failure at 24 months, the mean time of survival being 13.88 ± 8.25 months.

CONCLUSIONS

Management of corneal decompensation in childhood glaucoma poses a challenge. In this series of childhood glaucoma with corneal transplantations, the survival rate was 29% at 24 months.

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.

Intraoperative optical coherence tomography-guided donor corneal tissue assessment and preparation

Purpose

To evaluate the role of intraoperative optical coherence tomography (i-OCT) in donor grading, selection, and preparation during different types of keratoplasty.

Methods

Seventy-one consecutive donor corneas collected over 6 months, after clinical grading, were observed by an experienced corneal surgeon under an i-OCT equipped microscope. The donor preparation (manual/automated) for different types of keratoplasty procedures was also undertaken under i-OCT.

Results

The mean central corneal thickness of optical and nonoptical grade tissues was 533 ± 19 and 662 ± 52 μm, respectively. The i-OCT-based grading matched with clinical grading in 98.5% cases. Irregular thickness, anterior stromal hyperreflectivity, and previous scars were appreciated in 1.4, 1.4, and 7.04% donors, respectively. During Descemet stripping automated endothelial keratoplasty, i-OCT facilitated selection of appropriate microkeratome head for automated donor preparation in all cases, besides allowing manual dissection of partially dissected lenticule, identification of site of inadvertent perforation, and eccentric trephination in one case each. During Descemet membrane endothelial keratoplasty, i-OCT-based assessment of preexisting scar (five cases) guided careful tissue selection (2/5) and preparation. During predescemetic endothelial keratoplasty, precise needle advancement allowed successful type-1 bubble formation in all cases. All manually punched donors demonstrated an extra endothelial ledge, while those with automated preparation showed tapering donor margins.

Conclusion

i-OCT might serve as a useful imaging tool for objective assessment of donor characteristics. The modality may complement clinical evaluation for donor grading, selection, and preparation.

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.

Current Perspectives on Corneal Transplantation (Part 2)

Disease of the cornea is the third leading cause of blindness worldwide. Corneal graft surgery is one of the most successful forms of solid organ transplantations in humans, with ever increasing developments in surgical technique. To date, approximately 4504 corneal transplants are performed in the UK each year. While full thickness transplantation was the most commonly performed keratoplasty over the last few decades, selective lamellar transplantation of the diseased layers of the cornea has been universally adopted. This comprehensive review aims to provide an updated synthesis on different types of corneal transplantations, their treatment outcomes, and the associated complications of each procedure both in adult and pediatric populations. In addition, we also present an up-to-date summary of the emerging therapeutic approaches that have the potential to reduce the demand for donor-dependent keratoplasty.

Update on Suture Techniques in Corneal Transplantation: A Systematic Review

Effective suturing remains key to achieving successful outcomes in corneal surgery, especially anterior lamellar keratoplasty and full thickness transplantation. Limitations in the technique may result in complications such as wound leak, infection, or high astigmatism post corneal graft. By using a systematic approach, this study reviews articles and conducts content analysis based on update 2020 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria). The aim of this paper is to summarize the state of the art of corneal suturing techniques for every type of corneal transplant and patient age and also their outcomes regarding astigmatism and complications. Future developments for corneal transplantation will be also discussed. This is important because especially the young surgeon must have knowledge of the implications of every suture performed in order to achieve consistent and predictable post-operative outcomes and also be aware of all the possible complications.

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.