Indications and outcomes of keratoplasty ≤ 5.5 mm diameter (“mini-keratoplasty”)

PURPOSE: To report indications and clinical outcomes of corneal grafts ≤ 5.5 mm in diameter (“mini-KP”) in a German tertiary referral center. METHODS: Patients who had undergone mini-KP to treat corneal ulcers with or without perforation between 2011 and 2018 at the Department of Ophthalmology, University of Düsseldorf, Germany, were identified from the local keratoplasty registry. All patient records were reviewed for age, gender, laterality, systemic and ophthalmological diseases, etiology of the corneal ulcerative disease, pre- and postoperative visual acuity over a follow-up time of up to 12 months, graft size, postoperative complications and the need for and timing of further corneal interventions. RESULTS: 37 eyes of 37 patients (male: n = 20; female: n = 17) with a mean age (± standard deviation) at presentation of 70 ± 18.8 years (range: 22–92 years) were identified. Most common etiologies were neurotrophic keratopathy (n = 15), dysfunctional tear syndrome (n = 9) and atopic keratoconjunctivitis (9). Mean graft diameter was 4.51 ± 0.63 mm (range: 3-5.5 mm). 23/37 eyes (62%) required no further intervention in the acute phase. 14/37 patients (38%) required secondary corneal intervention, due to complications. One-year graft survival was 78.4%. One eye had to be eviscerated due to recurrent corneal ulceration and endophthalmitis. 36 of 37 eyes were preserved. We found a highly significant correlation between type 2 diabetes and the development of postoperative complications (r = .46; p = .005). Corrected distance visual acuity (CDVA) improved from 1.42 ± 0.75 logMAR to 0.9 ± 0.65 logMAR postoperatively (t (23) = 5.76; p < .001). CONCLUSION: Mini-KP can be used successfully in eyes with advanced corneal ulcers due to various infectious and noninfectious etiologies to restore tectonic stability in the long-term and with moderate visual gains.