IOP control still good 13 years after phacotrabeculectomy

A retrospective case series at a tertiary hospital in Singapore has shown that the cumulative surgical success rate after phacotrabeculectomy remains high at 89.1 percent even 13 years post-surgery, with success defined as intraocular pressure (IOP) ≤21 mm Hg.

With more stringent definitions of IOP ≤18 and ≤15 mm Hg, it remained that over 50 percent of the treated eyes were considered surgical success at 13 years (76.9 percent and 50.3 percent, respectively).

From a mean IOP of 20 mm Hg before the same-session cataract extraction and glaucoma filtering surgery, there were significant reductions in the mean IOP at all observed postoperative time points (p<0.001), dropping to 12.6 mm Hg at 13 years. A ≥20 percent reduction in IOP was achieved in 72 percent of the treated eyes. [Asia Pac J Ophthalmol (Phila) 2024;13:100102]

“Our study showed that combined phacotrabeculectomy surgery in Asian eyes has good long-term outcomes,” said lead author Dr Annabel Chew from the Singapore National Eye Centre (SNEC), Singapore. “In our series, phacotrabeculectomy was effective at controlling the IOP long-term.”

Largest series of Asian subjects

Phacotrabeculectomy is a combined procedure of phacoemulsification and trabeculectomy, allowing for the treatment of both cataract and glaucoma in a single surgical session. For indicated patients, the combined surgery minimizes surgical visits and the overall period of visual rehabilitation. It may also reduce the risk posed to the other coexisting condition when either procedure is performed alone.

All patients who underwent phacotrabeculectomy at SNEC between 2005 and 2007, with a minimum follow-up duration of 3 years, were reviewed. The study included eyes with primary open-angle glaucoma, primary angle-closure glaucoma (PACG), normal-tension glaucoma, and secondary glaucoma. Analysis was performed on 796 eyes of 698 patients (mean age 69.5 years, 50.6 percent male).

“This study represents the largest series of Asian subjects who have undergone phacotrabeculectomy, with a long duration of follow-up (mean 9.4 years),” said Chew.

Best corrected visual acuity, a secondary outcome measure, slightly improved from a mean of 0.57 logMAR^* before surgery to 0.55 logMAR at the final visit (p<0.001).

The proportion of eyes requiring glaucoma medications significantly decreased from 96.4 percent before phacotrabeculectomy to 49.6 percent at the last postoperative follow-up (p=0.005). The mean number of topical glaucoma medications required also decreased from 1.9 before the combined procedure to 1 postoperatively (p<0.001).

Overall, 5.5 percent of the treated eyes required additional glaucoma surgeries, with surgeries for bleb-related complications reported in 3.3 percent and additional IOP-lowering surgeries in 2.3 percent of the eyes. The mean duration between phacotrabeculectomy and the additional IOP-lowering surgery was 6.2 years.

Factors contributing to success rates

In the case series, antimetabolites were routinely used during surgery, with a particular preference for mitomycin C (96.2 percent vs 5-fluorouracil for the rest). “Although postoperative anterior chamber inflammation is prolonged following phacotrabeculectomy, good bleb survival can be achieved with the routine use of intraoperative mitomycin C in our population,” the authors pointed out, contrasting this with the long-term findings of the Singapore 5-Fluorouracil Study. [Ophthalmology 2013;120:1127-1134]

“Also, the prevalence of PACG in our population (33.9 percent) is higher than that in Caucasian populations, and lens removal can contribute to the increased rate of successful outcomes in PACG,” said Chew and colleagues, who also cited the use of releasable sutures and early adjunctive ibuprofen as changes in surgical techniques that can further improve outcomes following phacotrabeculectomy.