Author reply

We are grateful to Dr Sangtam for the interest in our article, and for raising 2 interesting issues for further discussion. Based on previously available data, we find it hard to draw a simple conclusion that advanced and medically uncontrolled chronic angle-closure glaucoma (CACG) eyes would have better outcomes with filtration surgery (combined phacotrabeculectomy or trabeculectomy). From our earlier study comparing phacoemulsification with phacotrabeculectomy in uncontrolled CACG eyes with cataract, combined surgery resulted in a further 2 mmHg lowering in mean intraocular pressure (IOP) and a reduction of 1.25 in mean number of glaucoma drugs, compared with phacoemulsification alone over 2 years of follow-up. From this present study, the advantages of trabeculectomy over phacoemulsification in IOP lowering were even smaller: 0.75 mmHg lowering in mean IOP and a reduction of 1.06 in mean number of glaucoma drugs over 2 years. The clinical significance of these differences remains uncertain in angle-closure glaucoma. To achieve this small additional IOP lowering and drug reduction, the groups undergoing filtration surgeries had to face significantly more surgical complications: 26.2% in the phacotrabeculectomy group versus 8.1% in phacoemulsification group in CACG eyes with cataract, and 45.8% in trabeculectomy group versus 3.8% in phacoemulsification group in CACG eyes without cataract. Eyes undergoing filtration surgery may also need more subsequent operative interventions during follow-up. Taking into consideration the possibility that CACG eyes with more advanced disease may be exactly those eyes that are less able to tolerate surgical complications and further surgery, the clinical benefits of filtration surgery over phacoemulsification in advanced CACG eyes are not clear cut.