Ocular biometric changes after trabeculectomy

Abstract

Introduction/Objective Trabeculectomy is a conventional filtration procedure in surgical glaucoma treatment. Even after successful trabeculectomy, the patient’s visual acuity can be reduced. Studies (1991) showed that changes in visual acuity occur due to changes of corneal curvature and anterior chamber depth. Anterior chamber depth change for 1 mm results in about 2 diopters change in refractive sphere. Simultaneous with anterior segment changes, anti-glaucoma surgery effect can also be manifested in posterior segment of the eye: choroidal thickness, axial length and the ocular perfusion. Axial length reduction after trabeculectomy was supposed according to biometry, more pronounced if intraocular pressure is higher preoperatively, or in the first postoperative week with spontaneous recovery to pre-operative values one year after surgery. A study was conducted at the Clinic for Eye Diseases in Niš to determine the difference in pre/post-operative values of biometry on 60 patients with glaucoma.

Methods In this study we used retrospective-prospective biometric analysis in patients with open-angle glaucoma.

Results Anterior chamber depth was significantly different during the observed period, for 1.1 mm in first week (p < 0.0001) in the whole group and glaucoma type. The mean axial length varies considerably during the observed period, shorter for 0.39 mm in first week (p < 0.05).

Conclusion By analyzing biometric parameters, a postoperative difference of biometry with spontaneous recovery was determined. There is a difference in postoperative visual acuity of patients compared to preoperative, with spontaneous recovery at the end of the follow-up.

Keywords: glaucoma; trabeculectomy; ocular biometry; anterior chamber depth; axial length