Combined Intrastromal Implantation of a Semipermeable Hydrogel Membrane in Case of Corneal Graft Failure and Multiple Keratoplasty (Clinical Observation)

Introduction: penetrating keratoplasty (PK) is an effective method for the surgical treatment of corneal failure and its layers and low visual acuity. It is well-known that the graft degrades over time, it is associated with “chronic immune destruction”. Rekeratoplasty is conducted in case of rapid decrease of transplant functions, but even with multiple rekeratoplasty iterations, the result can be unstable.Patient and methods. Patient D., 42 years old, complaints to low vision of left eye — arm movement 10 cm on face. Both eyes have been previously surgically operated for the last 10 years. Two iterations of an artificial iris transplantation in combination with IOL implantation, and Ahmed drainage implantation and five rekeratoplasty on the left eye were conducted. Corneal graft failure with transplant thickness — 802 μm. The patient suffers from Mediterranean fever and polyarthritis. We conducted a course of conservative therapy, which increased visual acuity to 0.05. Then we performed a surgical procedure for hybrid type of keratotransplantation. The following procedures were gradually conducted: mechanical removal of epithelium, femto-laser formation in a recipient’s replaceable corneal disk formation with 500 μm thick and a diameter of 7.0 mm, removal of disk, femto-laser formation of a central penetrating hole with a diameter of 3 mm opposite the artificial pupil, placing of the hydrogel graft 60 μm thick on the bottom of the bed. Hydrogel graft was covered by a donor corneal graft, which was fixed by interrupted sutures and soft contact lens.Results: Visual acuity of the left eye after 1 day after keratoplasty — 0.2; after 1 month — 0.3, the transplant was transparent; after 4 months — 0.4 with complex correction — 0.7, the transplant was transparent, the thickness of the donor disc — 275 μm.Conclusion. After multiple rekeratoplasty iterations the presented method of combined keratotransplantation allows to obtain a non-permanent effective result. At the same time, the polymer metabolism is preserved, since it has a circulation with the front camera. The case requires further observation.

Effectiveness of Histocompatibility Matching in High-Risk Corneal Transplantation

The Collaborative Cornea Transplant Studies (CCTS) comprised two randomized, double-masked, clinical trials, the Antigen Matching Study (AMS) and the Crossmatch Study (CS), designed to determine whether matching HLA-A, -B, and/or HLA-DR antigens, donor-recipient crossmatching, or ABO compatibility reduced the risk of corneal allograft rejection and failure in high-risk patients. The studies showed that for patients needing a corneal graft with uncompromised immune systems and at high risk for corneal graft rejection: (1) neither HLA-A, -B, nor HLA-DR antigen matching substantially reduces the likelihood of corneal graft failure; (2) a positive donor-recipient crossmatch does not dramatically increase the risk of corneal graft failure; and (3) ABO blood group matching may be effective in reducing the risk of graft failure. Intensive steroid therapy after transplantation, frequent follow-up, medication and follow-up compliance, and patient education appear to play a significant role in corneal graft success.

Graft Survival after Penetrating Keratoplasty in Cases of Trabeculectomy versus Ahmed Valve Implant

Purpose. To compare the corneal graft survival rates after penetrating keratoplasty (PKP) in cases of post-PKP glaucoma managed by either trabeculectomy with mitomycin C or Ahmed glaucoma valve (AGV). Methods. This study was a retrospective interventional comparative study that included 40 eyes of 40 patients. The included patients had undergone previous PKP for anterior segment reconstruction after microbial or fungal keratitis, chemical burns, trauma, or perforated corneal ulcer. Post-PKP glaucoma was managed surgically by either trabeculectomy with mitomycin C (group 1) or Ahmed glaucoma valve (group 2). Results. The first group n=20 had undergone trabeculectomy with MMC, and the second group n=20 had undergone AGV implantation. Regarding BCVA, there was no statistically significant difference between the 2 groups. Mean IOP was significantly lower in the AGV group at 6 months, 12 months, and 24 months p=0.001. Mean IOP at 24 months dropped significantly from preglaucoma surgery levels in both groups p=0.001. Rejection episodes occurred in 2 eyes (10%) of the trabeculectomy group versus 8 eyes (40%) in the AGV group p=0.028. In the trabeculectomy group, corneal graft failure occurred in 1 (5%), 3 (15%), and 6 (30%) eyes at 6 months, 12 months, and 24 months, respectively. In the AGV group, corneal graft failure occurred in 2 (10%), 5 (25%), and 10 (50%) eyes at 6 months, 12 months, and 24 months, respectively. The mean time to failure in the trabeculectomy group was 12.33 ± 5.60 months versus 11.90 ± 5.70 months in the AGV group p=0.027. Conclusion. Managing postpenetrating keratoplasty glaucoma could be bothersome especially in complex cases. Ahmed glaucoma valve implant controls the intraocular pressure more effectively than trabeculectomy with mitomycin C. However, Ahmed glaucoma valve can result in higher rates of corneal graft failure in a shorter duration of time. This trial is registered with PACTR201712002861391 on 21 Dec 2017.

Outcomes of Pars Plana Vitrectomy in Combination With Penetrating Keratoplasty

Purpose: To report indications and outcomes of combined pars plana vitrectomy and penetrating keratoplasty (PPV-PKP). Methods: A review of all patients who underwent PPV-PKP at the Illinois Eye and Ear Infirmary from January 1, 2001 to May 31, 2013, was performed. Ninety eyes of 90 patients were identified. Survival analysis was utilized to assess differences in retinal detachment (RD) and corneal graft failure rates among groups based on clinical and surgical variables. Results: Seventy-nine eyes met the inclusion criteria. Most common indications for vitrectomy and corneal transplantation were RD (65%) and corneal decompensation (43%), respectively. The preoperative and final visual acuity (VA) logarithm of the minimum angle of resolution values were 2.7 (0.31) and 2.5 (0.67) (hand motions; mean [SD]; P = .02); 15% of eyes were ≥20/400 and 15% gained ≥2 lines of vision following surgery. Corneal graft failure occurred in 51% (40 eyes), recurrent RD in 28% (22 eyes), and hypotony in 25% (20 eyes). Silicone oil endotamponade was associated with postoperative RD ( P = .045), and previous ocular trauma was associated with postoperative corneal graft failure ( P = .023). Conclusion: Combined PPV-PKP surgery was likely to achieve stabilization of VA, with a minority of eyes achieving modest gains in VA.

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

ABSTRACT 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.