Endothelial keratoplasty

Descemet’s stripping endothelial keratoplasty (DSEK) and Descemet’s membrane endothelial keratoplasty (DMEK) appear to provide good visual acuity over the medium to long term, according to studies presented at the 25th ESCRS Winter Meeting. In a single-centre retrospective consecutive series study, eyes undergoing DSEK had 10-year graft survival of 79%, said Lana Fu FRCOphth, King’s College Hospital NHS Foundation Trust, London, UK. “DSEK remains a viable treatment option, especially in complex eyes with comorbidity,” Dr Fu added. The study involved 356 eyes of 263 patients who underwent DSEK from January 2006 to January 2020 and had a median follow-up of 6.0 years (range: 0.5-14 years). The patients had a mean age of 72 years (range 35-95 years). The indications for surgery included Fuchs’ endothelial dystrophy (FED) in 59%, pseudophakic bullous keratopathy (PBK) in 25%, and previous graft failure in 5%. Ten surgeons performed the procedures using a standardised protocol. In all eyes they prepared the donor buttons manually using the Melles technique. In the first year of the study they inserted the donor tissue with a forceps, but switched to using the Busin glide in 2007 and the Tan EndoGlide in 2010. Dr Fu noted that 189 (53%) eyes had low visual potential preoperatively due to ocular co-morbidities, glaucoma, age-related macular degeneration, optic neuropathy and retinal detachment surgery. Cumulative graft survival of all eyes, including those with complex co-morbidities, was 85% at five years and 79% at 10 years, Dr Fu pointed out. Among eyes with glaucoma, the cumulative graft survival was 52% at five years and 35% at 10 years, among eyes with PBK it was 89% at five years and 62% at 10 years and among eyes with FED it was 97% at five years and 92% at 10 years. The endothelial cell loss of all grafts was 46.5% at one year, 54.9% at three years, 59.21% at five years and 75.65% at 10 years. After exclusion of the failed grafts there was no statistically significant increase in central corneal thickness, she noted. Complications included interface fluid, which occurred in 52 (14.6%) eyes, and re-bubbling was performed in 29 eyes (8.1%). There were also 70 (19.7%) rejection episodes, half of which occurred in eyes that had preoperative glaucoma. Graft failure occurred in 50 (14%) eyes, of which 27 underwent repeat transplants. GOOD VISION MAINTAINED FOR FIVE YEARS AFTER DMEK Another retrospective study, presented at the ESCRS meeting by Nikolaos Kappos MD, suggested that eyes undergoing DMEK maintain normal visual acuity levels for five postoperative years despite some loss of transparency. The study involved 60 eyes of 51 patients who underwent DMEK at the Philipps University of Marburg, Germany. The patients had a mean age of 67 years and their indications were FED in 53 (88%) cases and BK in seven (12%) cases. None included in the analysis had undergone previous corneal surgery, complicated perioperative course, vision-limiting ocular comorbidity and/or incomplete follow-up data, said Dr Kappos, National and Kapodistrian University of Athens, Athens, Greece. The primary outcome in the study was corneal densitometry, a measure of light scatter as determined with the Pentacam HR (Oculus). Secondary outcomes were best corrected visual acuity, endothelial cell density measured with the Topcon SP2000P and central corneal thickness measured with the Pentacam HR. “Light scattering constitutes a significant parameter in the evaluation of the corneal optical performance since back scatter interferes with its transparency. The rotating Scheimpflug camera in the clinical settings enables the objective quantification backscatter in greyscale units (GSU) in different layers and zones,” Dr Kappos said. The study showed that mean corneal density decreased significantly in the central and paracentral zone for up to two years but increased slightly between the second and fifth year, although it remained significantly lower than the preoperative value (21 GSU vs 33 GSU, respectively). In the mid-peripheral zone there was no change in corneal density postoperatively for up to two years, but there was a considerable increase between the second and fifth years, reaching levels higher than preoperative values. Similarly, mean central corneal thickness decreased significantly from 686μm preoperatively to 527μm at three months but by two years had increased to 542μm and by five years had increased to 557μm. Mean endothelial cell density decreased by 60% from 2,500 cells/mm² prior to implantation to 1,000 cells/mm² at five years. Nonetheless, visual acuity improved from 0.3 (Snellen decimal) preoperatively to 0.8 (Snellen decimal) at six months and remained stable thereafter. “Despite a slight corneal density increase at all layers of all corneal zones from the second to the fifth postoperative year, the excellent visual outcome was maintained throughout five years’ follow-up. Thus, DMEK seems to treat effectively corneal endothelial disease in the long term,” Dr Kappos concluded. Lana Fu: LFu@Doctors.org.uk Nikolaos Kappos: nickappos@gmail.com