Abstract
Purpose: :
To compare the functional outcome of fornix-based trabeculectomy with mitomycin C using two different sizes of subconjunctival preparation (6x6 mm compared to 8x9 mm).
Methods: :
In a prospective, masked study 28 eyes of 26 glaucoma patients (including 22 eyes with primary open angle glaucoma, 4 normal tension glaucoma and 2 pseudoexfoliative glaucoma eyes) with progressive visual field defects underwent trabeculectomy augmented with mitomycin C. All surgeries were performed by one experienced surgeon (NP). Patients were randomized to 2 different groups: The first group (14 eyes) received fornix-based subconjunctival preparation of 6x6 mm while the second group (14 eyes) received an 8x9 mm subconjunctival preparation. Exclusion criteria were previous conjunctival surgery, chronic conjunctivitis, and application of antiglaucomatous drops 4 weeks prior to surgery. Follow-up examinations at day 1, 7, month 1, 3, and 6 postoperatively included assessment of visual acuity, IOP measurement, number of 5-fluorouracil injections, and number of laser suturolyses,
Results: :
Mean IOP preoperatively was 25.1 ± 17.1 mm Hg in group 1 and 30.6 ± 13.6 mm Hg in group 2. In the first group, IOP was lowered to: 17.7+/-6.2 mmHg on the first day; 8.6+/-4.8 mmHg on the 7th day; 9.1+/-2 mmHg at 4 weeks; 9.8+/-2.7 mmHg at 3 months; and to 9.2+/-2.3 mmHg at 6 months (without antiglaucomatous medication). In the second group IOP was lowered to: 19+/-6.4 mmHg; 10.9+/-5 mmHg; 11.7+/-3.2 mmHg; 10.3+/- 2.6 mmHg; and 10+/-3.1 mmHg respectively. The IOP reduction in both groups was significant (p=0.000). Only 4 weeks postoperatively, IOP in group 1 was significantly lower than in group 2 (9+/-2 mmHg versus 11.7 ± 3.2 mm Hg (p = 0.015). Patients in the first group required 3+/-2.6 5-FU injections and 1.3+/-1.1 laser suturolyses. In the second group 4.6+/3 5-FU injections and 1.8+/-1.1 laser suturolyses were required. The difference between both groups was not significant.
Conclusions: :
The size of the subconjunctival preparation seems to have no influence on postoperative outcome as defined by IOP. Six months postoperatively no significant difference between the groups regarded IOP was found. The number of subconjunctival 5-FU injections and laser suturolyses in both groups did not differ significantly. Although one might have thought that a larger size of subconjunctival preparation in trabeculectomy may lead to increase of aqueous humor outflow, this study showed that this is not the case. Outcome is therefore, dependent on factors other than the size of the subconjunctival preparation.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • clinical (human) or epidemiologic studies: outcomes/complications • clinical research methodology