Comparison of Phacotrabeculectomy and Trabeculectomy in the Treatment of Primary Angle-closure Glaucoma (PACG)

Overview

Primary angle closure glaucoma (PACG) is caused by contact between the iris and trabecular meshwork, which in turn obstructs outflow of the aqueous humor from the eye. This contact between iris and trabecular meshwork (TM) may gradually damage the function of the meshwork until it fails to keep pace with aqueous production, and the pressure rises, and at last the optic nerve is damaged, the vision may be lost in some severe cases. Therefore, ocular pressure reduction is the key to treat the disease and prevent blindness. Trabeculectomy is the most common conventional surgery performed for glaucoma. This allows fluid to flow out of the eye through this opening, resulting in lowered intraocular pressure(IOP) and the formation of a bleb or fluid bubble on the surface of the eye. Cataract surgery is common in the elderly. Cataract surgery is the removal of the natural lens of the eye (also called "crystalline lens") that has developed an opacification, which is referred to as a cataract. Cataract extraction includes intracapsular cataract extraction, extra capsular cataract extraction \& phacoemulsification, and phacoemulsification is the preferred method. It has been reported that IOP reduction could occur in cataract patients with PACG after the cataract surgery. For some cases with PACG, such IOP reduction may be insufficient for neuronal protection, and many patients still require glaucoma medication and incisional surgery such as trabeculectomy to control IOP. In such cases, a combined cataract-glaucoma procedure (phacotrabeculectomy) is a reasonable option. In keeping with this concept, previous studies have shown that phacotrabeculectomy could effectively and simultaneously reduce IOP and improve vision in patients with a coexistence of PACG and vision-threatening cataract. However, phacotrabeculectomy may heighten inflammatory response, result in a higher frequency of postoperative complications such as hyphema and fibrin in the anterior chamber, endophthalmitis, and increased scarring of the filtering bleb. Thus, it is unclear whether phacotrabeculectomy is as effective and safe as trabeculectomy in lowering IOP for PACG patients. In the present study, the investigators compared the efficacy and safety of phacotrabeculectomy and trabeculectomy in patients with coexisting PACG and cataract.