Visual evoked potentials changes with surgery in primary congenital glaucoma: a pilot study

Objective To report the flash visual evoked potential (VEP) findings in children with primary congenital glaucoma (PCG) before and after successful surgical control of the intraocular pressure (IOP). Methods The study enrolled children presenting with PCG to the Ophthalmology Department of Alexandria Main University Hospital in the period between June and December 2019. All study participants were subjected to a standard protocol of examination, to confirm the diagnosis of PCG. The child was then referred for flash VEP testing. Peaks were designated as negative and positive waves in a numerical sequence (N1, P1, N2, P2, N3 and P3). The child was then scheduled for surgery within 1 week of presentation. Postoperative VEP testing was scheduled as soon as feasible and was conducted in the same way as the preoperative VEP testing. Results The study was conducted on 11 (four right) eyes of eight (five males) children. The mean +/- standard deviation of the age of the study children at presentation and at postoperative VEP testing was 3.5 +/- 1.6 and 5.1 +/- 3.0 months, respectively. The study eyes mean +/- standard deviation IOP at presentation and at postoperative VEP testing was 23.0 +/- 6.7 and 8.3 +/- 2.4 mmHg, respectively (p < 0.0001). There were a statistically insignificant reduction in P2 implicit time (p = 0.235) and a statistically insignificant increase in each of N1-P1 (p = 0.15) and N2-P2 (p = 0.67) amplitudes postoperatively than preoperatively. Conclusions IOP elevation in PCG adversely affects the optic nerve function, but, at least in the short term, has no permanent detrimental effect on the optic nerve function as evidenced by the improvement in the VEP parameters.