Assessment Of Anterior Chamber Angle Changes After Pars Plana Vitrectomy Using Ultrasound Biomicroscopy

We aimed to compare the impact of pars plana vitrectomy (PPV) on anterior chamber angle parameters based on ultrasound biomicroscopy (UBM) measurements.

Department of Ophthalmology of the Military Hospital, Tunis, Tunisia.

A prospective comparative study was conducted between June 2021 and October 2021. Ten phakic eyes of 10 patients, scheduled for PPV, were enrolled. A comprehensive ophthalmic examination was performed for each patient including slit-lamp evaluation and fundus examination. Anterior segment imaging was performed on each eye using ultrasound biomicroscopy (UBM,Aviso Lin-50; Quantel Medical). The following biometric parameters of the anterior segment were measured preoperatively and 3 months postoperatively: Lens vault (LV), angle opening distance (AOD 500), angle recess area (ARA 750) and trabecular iris space area (TISA 750). We compared all measurement evaluation preoperatively and 3 months postoperatively.

The mean age was 63.6±10.8 (6 male and 4 female). The preoperative diagnoses comprised six eyes with rhegmatogenous retinal detachment (RDD), three with epiretinal membrane, and one with a macular hole. All the surgeries were carried out by the same surgeon using similar surgical procedure. There was a significant increase in the LV after PPV (0,45 ± 0.13 vs 0,49 ± 0,16; p = 0.036). The slit-lamp examinations indicated that there was an increase in the opacity of the crystalline lens in six of the ten patients. Compared to preoperatively measurements, there were no significant changes in the iridocorneal angle parameters (AOD 500, ARA 750, TISA750) at the 3 month-postoperatively control (all p>0,05).

The LV was the only parameter measured using UBM that changed significantly following PPV. Thus, this can be expected after PPV due to the development of nuclear sclerotic cataracts.