Abstract
Purpose::
Implanting the ExPRESS device under a scleral flap may result in successful control of IOP (intra-ocular pressure) in glaucoma. Bleb formation, especially large and cystic blebs are undesirable, and may increase complications in the medium to long-term. A study was done to examine the nature of the bleb formed when the ExPRESS device was implanted under a well-sealed scleral flap with mitomycin C applied under the scleral flap.
Methods::
Non-randomized prospective study. Outcome measures included intra-ocular pressure, number of anti-glaucoma medications, bleb size and complications with follow-up reaching two years in 70% of the patients.
Results::
Fifty-eight eyes of 50 patients with open-angle glaucoma (OAG) were implanted under a scleral flap with the ExPRESS miniature glaucoma device. Half (29 patients) had the surgery combined with cataract extraction and intra-ocular lens. Twenty eyes (35%) had received previous glaucoma surgery. There were 32 Caucasians, 6 Africans, 10 Asians and 2 of Mixed race in the group. Mean IOP (±SD) dropped from 29.4 mmHg (±6.9, 58 eyes) preoperatively to 13.5 mmHg (±2.8, 58 eyes) at one year and 14.2 mmHg (±2.9, 41 eyes) at two years. The drop in IOP was significant between baseline and one and two years (t test, p=0.000) and there was no difference between the IOP’s at one and two years (p=0.263). Eighty-five percent (49 eyes) showed absent or minimal blebs (under 1mm height) at one year, with 12% (7 eyes) showing medium-sized blebs (1-2mm)and 3% (2 eyes) showing large blebs (over 2mm). At two years, 88% (36/41 eyes) had absent or minimal bleb formation with 7% (3 eyes) having medium blebs and 5% (2 eyes) with large blebs. Mean number of medications dropped from 2.5 preoperatively (58 eyes) to 0.02 at one year (58 eyes) and 0.3 at two years (41 eyes). Six eyes required surgery for procedure-related problems.Complete success (IOP≤18 mmHg without anti-glaucoma medications) at one year was 53/58 (91%) and partial success (IOP≤18 mmHg with anti-glaucoma medications) in a further one eye. Complete success at two years was 35/41 (85%) and partial success was seen in a further three eyes. Higher IOP’s were seen in the non-Caucasian patients and complete success was significantly higher in Caucasians at one year (chi-square, p=0.025). There was no association between bleb size and complete success at one or two years.
Conclusions::
Implanting the ExPRESS miniature glaucoma device under a scleral flap resulted in good IOP control, with reduced anti-glaucoma medication and with minimal bleb formation.
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • intraocular pressure • wound healing