The mean pretreatment IOP was 26.2 ± 3.8 mm Hg. There was a trend toward further IOP reduction at 6 months compared with 1 month (table 3). There was no significant relationship between the height of the ciliary body face, trabecular meshwork, or Schwalbe's line-iris insertion distance and the efficacy of latanoprost. These researchers concluded that, although latanoprost lowers IOP by enhancing uveoscleral out-flow, its mechanism of action is independent of trabecular and ciliary face height. There is a trend toward increasing efficacy of latanoprost over time.

Table 3. Effect of latanoprost on intraocular pressure (IOP) over time

1 Month 2 Months 3 Months 6 Months Mean IOP reduction from baseline (mm Hg) 7.0 7.7 8.7 10.0

Influence of 5-FU on IOP Control Following Drainage Surgery

Ivan Goldberg Eye Associates Sydney, Australia

Dr Goldberg presented a study assessing the safety and efficacy of 5-fluorouracil (5-FU) following trabeculectomy and phakotrabeculectomy surgery.

186 eyes of 186 patients were divided into 4 groups, analysed retrospectively, and followed up for 2 years. 51 patients underwent trabeculectomy surgery with postoperative 5-FU, 51 patients underwent phakotrabeculectomy with postoperative 5-FU, 56 patients had trabeculectomy with intra- and postoperative 5-FU, and 28 patients had trabeculectomy surgery with no antimetabolite.

All groups had a reduced mean intra-ocular pressure (IOP) at 24 months (p < 0.001). The success rates at 24 months fol-lowing surgery with or without the addition of 5-FU are shown in table 4. Overall, these differences were statistically significant (p < 0.01).

Table 4. Success rates following surgery with or without additional 5-fluorouracil (5-FU)

Trabeculectomy with postoperative 5-FU Phako- trabeculectomy with postoperative 5-FU Trabeculectomy with intra- and postoperative 5-FU Trabeculectomy with no 5-FU Success rate (IOP < 16 mm Hg and > 30% IOP reduction) 71% 55% 76% 29%

 

Dr Goldberg concluded that 5-FU is safe and improved success rates. Intra-operative 5-FU allowed for a lower post-operative dosage to be given and fewer side effects without impacting on the success. Phakotrabeculectomy plus 5-FU showed a lower hypotensive success rate than trabeculectomy with postoperative 5-FU.

Effect of IOP Reduction on Visual Field Progression in NTG Following Trabeculectomy

Luke Membrey
Glaucoma Research Unit
London, UK

A study was performed to determine the relationship between change in intraocular pressure (IOP) following drainage surgery and risk of visual field progression in 61 eyes of 61 patients with normal pressure glaucoma (NTG) who had at least 5 visual field tests and 6 months follow up after surgery.

The median IOP from the 2 years prior to surgery was the baseline and the median IOP from each successive 6 months was recorded. Pointwise linear regression analysis was applied to the visual field series.

Progression of visual field loss was defined as the consistent appearance of a regression slope of 1 dB per year or more with a significance of p < 0.01. Time updated covariate analysis was used to determine the relationship between IOP and the risk of progression. The median postoperative follow up was 42 months.

There was a statistically significant relationship between percentage change in IOP and risk of visual field progression in the subsequent 6-month period (p = 0.002). Dr Membrey concluded that, in NTG, the percentage drop in IOP during a given time period after drainage surgery is related to the risk of subsequent visual field progression.