Ahmed drainage implantation results for the patients with the secondary glaucoma and severe burn vascular leucoma in pre- and post-keratoprosthesis

Purpose. To assess an efficacy and results of Ahmed drainage implantation in patients with severe burn vascular leucoma and secondary glaucoma in case of pre- and post-keratoprosthesis. Material and methods. The Ahmed drainage implantation glaucoma surgery was performed using the Ahmed FP7 model (New World Medical, Inc., USA) in 89 patients (89 eyes) with burn vascular leucoma of category IV-V. The Ahmed drainage implantation glaucoma surgery before keratoprosthesis was carried out in 28 eyes (31.5%), simultaneously with keratoprosthesis - in 45 eyes (50.6%), after keratoprosthesis (at the periods from 2 months to 3 years) - in 16 eyes (17.9%). There was used the Fyodorov-Zuyev keratoprosthesis design. The keratoprosthesis implantation was performed in 2 stages using the standard technique. Results. A statistically significant decrease of the average intraocular pressure (IOP), measured by the transpalpebral tonometry, after the Ahmed drainage implantation was obtained in patients with burn vascular leucoma of category IV. The IOP indices became stable 1 month after the surgery and remained unchanged up to the 4 year follow-up period. Any complications of Ahmed drainage implantation were not observed in the early postoperative period (1-10 days). Complications were found in 16 eyes (18%) in the late postoperative period (11 days - 4 years). The most wide spread complication was an Ahmed drainage incapsulation in 10 eyes (11.2%). Other complications, connected with the features of anterior segment status of vascular leucoma in burn etiology and keratoprosthesis presence, but not the drainage itself, were: Ahmed drainage tube dislocation from the anterior segment in 3 eyes (3.4%), drainage tube occlusion in 1 eye (1.1%) and drainage tube protrusion in 2 eyes (2.3%). As a result of the performed treatment an improvement of vision was detected in 76 of 89 patients. The visual acuity varied from 0.02 to 0.1 in 38 eyes (42.6%) from 0.1 to 1.0 - in 51 eyes (57.4%). One of the main causes of low visual acuity postoper atively was optic nerve atrophy. Conclusions. The Ahmed drainage implantation surgery in patients with secondary glaucoma and severe burn vascular leucoma significantly reduces the quantity of additional glaucoma surgeries and allows to obtain a stabilization of eye physical functions in 98.9% of patients in the 4 year follow-up period. It promotes a creation of favorable conditions for the next keratoprosthesis in these patients.