Changing trends in the incidence of bleb-related infection in trabeculectomy

AIM

To investigate the incidence of late onset bleb-related infection (BRI) following Mitomycin C (MMC) augmented trabeculectomy procedures at a single institution.

METHODS

This was a retrospective case series analysis of late onset BRI, defined as either blebitis or endophthalmitis occurring at least 1 month following a glaucoma filtration procedure. Data collected from hospital charts included the position of the conjunctival flap base. Two cohorts were examined: the first a sample of 194 intraoperative MMC augmented trabeculectomies undertaken over a 4-year period from 1993 to 1997, and the second a sample of 764 MMC trabeculectomies performed in a 4-year period between the years 1999 and 2005.

RESULTS

A total of 11 cases of BRI (cumulative incidence 5.7%) were identified in the cohort from 1993 to 1997. BRI cases had trabeculectomies performed with a limbus-based conjunctival flap and presented at a median IQR 14.8 (9.4-42.9) months after surgery. In the 1999-2005 cohort, nine cases of BRI were identified (cumulative incidence 1.2%). All these BRI cases had a fornix-based conjunctival flap and presented at a median IQR 19.2 (6.1-44.1) months after trabeculectomy surgery.

CONCLUSION

This study found that the incidence of BRI was higher in MMC augmented trabeculectomy shortly after the introduction of MMC, but subsequently reduced to a lower level. While many changes in surgical technique had occurred in the intervening period, the most significant change was from limbus-based to fornix-based conjunctival flap. However, the retrospective nature of the study prevents the authors from concluding that there is a causative relationship between changes in surgical technique and BRI.

Association of POAG risk factors and the Thr377Met MYOC mutation in an isolated Greek population

PURPOSE

To characterize the MYOC genotype correlation with phenotypes in an isolated Greek population with a high incidence of glaucoma.

METHODS

Five hundred thirty-one villagers were enrolled in the study. Participants underwent a comprehensive ophthalmic examination. All three exons of myocilin were bidirectionally sequenced. Power calculations and measured genotype analysis was conducted using the genetic variance analysis program, SOLAR version 4.2, to account for the relatedness between individuals.

RESULTS

The participants, 376 of whom were linked in a single 11-generation pedigree, ranged in age from 10 to 95 years with a mean age of 49. Sixty-five individuals had POAG, and 27 of those carried the Thr377Met MYOC mutation. Both peak intraocular pressure and vertical cup-to dis- ratio were significantly associated with the MYOC Thr377Met variant (P = 9 x 10(-14) and P = 9 x 10(-8), respectively), whereas central corneal thickness showed no significant association (P < 0.7).

CONCLUSIONS

This village had a high frequency of glaucoma, with 12% of the participants aged 10 to 95 years having the disease. In this cohort, the Thr377Met MYOC mutation was significantly associated with both high intraocular pressures and high vertical cup-to-disc ratios. No association was found with central corneal thickness.

Twenty-four-hour efficacy of the brimonidine/timolol fixed combination versus therapy with the unfixed components

PURPOSE

To evaluate the 24-h intraocular pressure (IOP) control of brimonidine/timolol fixed combination (BTFC) versusthe unfixed combination of its individual components, each dosed twice daily, in patients with primary open-angle glaucoma or ocular hypertension.

METHODS

An observer-masked, randomized, crossover, active-controlled, two-centre comparison. Following a 6-week medicine-free period, patients were randomized to BTFC or to the unfixed combination of brimonidine and timolol for 3 months. Patients then were crossed over to the opposite treatment for another 3 months. At the end of the medicine-free period, and each treatment period, patients underwent 24-h IOP measurements at 0600, 1000, 1400, 1800, 2200, and 0200 hours.

RESULTS

Twenty-eight patients completed this study. Both BTFC and the unfixed components showed a significant IOP reduction from untreated baseline (P<0.0001), and were statistically equal when compared directly, for each individual time point and for the 24-h IOP curve (P>0.05). The mean 24-h IOP was 24.6+/-1.9 for baseline, 19.2+/-1.9 for BTFC, and 19.2+/-1.6 mmHg for the unfixed components (P=1.0). Four patients were discontinued due to side effects. The most common ocular adverse event was ocular hyperaemia (n=3 with BTFC and n=5 with the unfixed components, P=0.7) and systemic adverse events were rare.

CONCLUSION

This study suggests that both BTFC and the unfixed components of brimonidine and timolol provide a significant 24-h IOP reduction from untreated baseline, and statistically equal control when compared directly, at each time point and for the 24-h pressure curve.