Factors associated with surface epithelial keratopathy after optical penetrating keratoplasty

[Anterior stromal micropuncture for the treatment of persistent corneal epithelial graft defects after penetrating keratoplasty]

Persistent corneal graft erosion or persistent epithelial corneal defect is a frequent complication of penetrating keratoplasty. Its development can be contributed by the dry eye syndrome, rare blinking, lagophthalmos, symblepharon, viral infection, autoimmune aggression, and the use of epithelial-toxic eye drops. The article presents three clinical observations of patients who developed persistent corneal graft erosion after penetrating keratoplasty. Due to the ineffectiveness of local conservative therapy for more than 3 weeks, anterior stromal corneal micropuncture was performed. After the procedure, there was a gradual epithelial proliferation, complete healing of the corneal surface was observed 10-16 days after the manipulation, the follow-up period was at least 1 year. The mechanism of action of stromal micropuncture is associated with the creation of a porous surface with better adhesion properties, as well as with the activation of the production of extracellular matrix glycoproteins such as fibronectin, type IV collagen and laminin, which are necessary for stable adhesion of the epithelium. The use of stromal micropuncture of the donor flap in the treatment of post-keratoplasty persistent corneal epithelial defect was proposed for the first time.

Corneal graft failure: an update

Corneal graft surgery is one of the most successful forms of human solid-tissue transplantation, and nowadays, there is a worldwide expansion of the surgical volume of corneal grafts. This surgery is continuously evolving, with new surgical techniques and postoperative treatments that have considerably increased the chance of survival for the grafts. Despite the high rate of success, corneal transplantation is still complicated by a relevant risk of graft failure. This study investigates the causes that lead to the failure of the different corneal graft surgical techniques and provides an updated synthesis on this topic. A comprehensive review of the main pathological pathways that determine the failure of corneal grafts is provided, analysing the main risk factors and disclosing the survival rates of the principal form of corneal grafts. Our results revealed that penetrating keratoplasty has higher failure rates than lamellar keratoplasty, with immunological rejection being the leading cause of graft failure, followed by late endothelial failure (LEF) and ocular surface disorders. Postoperative glaucoma and dehiscence of the surgical wound represent other important causes of failure. Endothelial keratoplasty showed the lowest rates of failure in the mid-term, with LEF, detachment of the graft and primary graft failure representing the most common pathological reasons for failure.

Features of the epithelial layer formation on corneal graft

Relevance. Significant impact on graft survival has a delay in the formation of epithelial cover. Purpose cytological characteristics and analysis of the effect of medications on the epithelial layer formation on the graft. Materials and methods. An analysis of the post-operative state of 20 patients operated for bullous keratopathy and corneal ulcer. Smears from the surface of the graft were stained by Leucodif 200 (LDF 200) and examined by light microscopy. Results. The epithelial layer formation in all cases ended no later than 8-10 days after keratoplasty. According to the cytological analysis, a complex of postoperative treatment which included Vixipin from the 10th day of the postoperative period. Visual acuity improvement occurred in 11 patients (75% of cases) operated due for bullous keratopathy, and in four patients operated for corneal ulcer. Conclusions. The epithelial layer formation on the surface of corneal transplant occurs due to the migration of mature epithelial cells from the wound edges of the own cornea and mitotic activity of limbal cells of the recipient. Long-lasting epithelial defect and inflammation preceding keratoplasty result in slower epithelialization of the graft in the postoperative period. Use of corticosteroids, sodium hyaluronate and antioxidants in the postoperative period contribute to the formation of a full epithelial layer.

Autologous Platelet-rich Plasma Eye Drops Accelerate Re-epithelialization of Post-keratoplasty Persistent Corneal Epithelial Defects

Purpose:

To investigate whether autologous platelet-rich plasma (PRP) eye drops accelerate re-epithelialization of post-keratoplasty persistent corneal epithelial defects (PEDs).

Methods:

A total of 34 eyes with PEDs after keratoplasty (24 penetrating keratoplasty and 10 deep anterior lamellar keratoplasty) that were refractory to conventional medical treatments were treated with PRP eye drops every 3 hours. PRP eye drops were prepared with a low- and high-speed centrifugation method and final platelet counts were 700,000-800,000 plt/μl. The mean treatment duration for complete re-epithelialization was compared with the mean treatment duration of conventionally treated corneal defects before the PRP treatment by paired t-test. The mean treatment duration was also statistically analyzed between age groups, gender, indications for keratoplasty, and types of keratoplasty using analysis of variance (ANOVA).

Results:

Treatment with autologous PRP eye drops led to rapid re-epithelialization in all eyes. The mean treatment duration for complete re-epithelialization was 2.47 ± 1.21 weeks, which was significantly shorter than the mean treatment duration of conventionally treated corneal defects before PRP treatment (6.82 ± 1.24 weeks) (P = 0.0001). There was no significant correlation between re-epithelialization time and patients' age, sex, indications for keratoplasty, and techniques of corneal transplantation.

Conclusion:

Treatment with autologous PRP eye drops is an effective and reliable approach that accelerates re-epithelialization of post-transplantation PEDs.