Abstract
Purpose :
Trabeculectomy is the most common incisional surgery for glaucoma. Previous research suggests trabeculectomy can cause refractive changes by inducing with-the-rule astigmatism and shortening the axial length and anterior chamber. Some studies have examined trabeculectomy induced changes on refractive outcomes of simultaneous cataract surgery- none with cases performed by a technique described at ARVO 2019 (poster #B0083).
Methods :
This retrospective single surgeon consecutive case series compares refractive outcomes of combined phacoemulsfication microtrabeculectomy (“phacotrab”) and temporal incision phacoemulsification (“phaco”). Phacotrab features include two site surgery, partial thickness 2mm triangular scleral flap at the base secured by a 10-0 nylon suture at the apex, and conjunctival closure with single wing suture at the superior limbus. Cases with either surgery and 1 year follow-up between 1/1/2013 and 1/1/2019 were included. Exclusions included prior surgery in the operative eye, missing pre or postop manifest refraction, and severe corneal/retinal disease. Outcome variables are best corrected visual acuity (BCVA) logMAR equivalents within 1 postop year, refractive prediction error (RPE) defined by postop subjective spherical equivalent refraction (SER) minus Barrett Universal II V1.05 predicted SER, and mean absolute error (MAE)- absolute difference between actual and predicted SER. Descriptive statistics, T-test, and Chi-squared tests were performed.
Results :
29 patients met criteria for the phacotrab group. 38 patients meeting criteria for the phaco group were randomly selected. Average age, preop BCVA, Barrett SER, and axial length were the same in both groups (Table 1). Postop logMAR BCVA and MAE were the same for both groups; however, RPE varied (-0.246D phacotrab vs -0.235D phaco) p=0.047. The proportion of cases achieving refraction targets <0.5D, 0.5D to 1.0D, and >1.0D were the same among both groups (Table 2).
Conclusions :
Phacomicrotrabeculectomy cases achieve similar refractive outcomes to phacoemulsification cases within the first year. Postop BCVA and the ability to reach SER targets were the same in both groups. In our 67 patient sample, the phacotrab group manifested an average myopic surprise of 0.01D compared to phacos, but was not clinically significant enough to change refractive outcomes.
This is a 2020 ARVO Annual Meeting abstract.