Lens Extraction Combined With Goniosynechialysis Versus Trabeculectomy

Effectiveness of Lens Extraction Combined With Goniosynechialysis Versus Trabeculectomy in Treating Advanced Angle-closure Glaucoma: a Randomized Controlled Trial

To compare the effectiveness of lens extraction combined with goniosynechialysis and trabeculectomy in treating advanced angle-closure glaucoma.

Advanced angle closure glaucoma (AACG) can result in severe visual function defect or even blindness with or without acute attacks. Different from open angle glaucoma (OAG), the main principle of treatment for AACG is not only to lower intraocular pressure (IOP) but also to protect the anterior chamber angle from closing. Previously, the most common and classical treatment for AACG was trabeculectomy. However, both doctors and patients are not satisfied with this surgery because of its limited success rate due to fibrosis of the filtration pathway. Besides, trabeculectomy has various complications, such as shallow anterior chamber, choroidal effusion, suprachoroidal hemorrhage, malignant glaucoma, and bleb leakage associated endophthalmitis. In addition, patients who underwent trabeculectomy will have decreased visual acuity in a couple of years due to accelerated development of cataract. Since a thickened and anterior-positioned lens could play a crucial role in the pathogenesis of AACG, cataract surgery has also been used. Accumulative evidence shows lens extraction alone is an efficient way in treating the early stage of ACG but has limited success rate in AACG. Lens extraction combined with goniosynechialysis (LEG) has been proved to be better than lens extraction alone in re-opening the anterior chamber angle for ACG patients with extensive peripheral anterior synechia and possibly have better effect than trabeculectomy as well from our preliminary data, which has not been proved yet. Thus, this investigation is designed to compare the effect of LEG and trabeculectomy in AACG patients prospectively in 3 years of follow-up. The investigators hypothesize that LEG could have better IOP control and better visual function than trabeculectomy in long term for AACG patients.

Inclusion Criteria:

1. Age between 40 years old to 80 years old
2. more than 180-degree synechial closure of anterior chamber angle on gonioscopy
3. IOP higher than 21mmHg under the use of more than two anti-glaucoma eye drops
4. mean deviation of visual field worse than -12dB on Humphrey 24-2
5. phakic eyes

Exclusion Criteria:

1. Snellen visual acuity worse than 0.02
2. history of ocular trauma
3. uveitis
4. previous ocular surgeries
5. significant conjunctival scar
6. visible neovascular on iris or anterior chamber angle
7. other severe eye diseases that would affect visual function significantly, such as age-related macular degeneration and pathogenic myopia.