Evaluation of the effect of brinzolamide 1% ophthalmic suspension on nystagmus using videonystagmography

Purpose: To evaluate the effect of topical brinzolamide (Azopt) eye drops on nystagmus using videonystagmography in infants and children. Methods: Setting: Institutional (Cairo University Hospitals). Study population: Both eyes of 40 patients, presenting with nystagmus, with a maximal age of 14 years, were included in this prospective, nonrandomized, unmasked study. Intervention: Clinical evaluation and videonystagmography were carried out on entry, at 1 month, and 6 months of Azopt instillation and 1 month after its discontinuation. Azopt was stopped at 1 month in case of deterioration. Main outcome measures: The primary outcome of the study was the change in nystagmus intensity at 4 weeks of Azopt treatment, based on videonystagmography. Results: Mean age was 5.7 ± 3.3 years. There was a significant decrease in mean nystagmus amplitude from 8.39 ± 7.67, on entry, to 5.95 ± 5.31, 5.27 ± 4.64, and 4.18 ± 3.65 degrees at 1 month, 6 months, and 1 month after discontinuation ( P < 0.05). There was a significant decrease in slow phase velocity (SPV) from 29.53 ± 22.19, on entry, to 20.43 ± 18.62 degrees/second at 6 months, and in nystagmus intensity from 1018.4 ± 1530.9, on entry, to 319.3 ± 322.05 at 6 months ( P < 0.05). Decrease in nystagmus frequency and visual improvement were insignificant ( P > 0.05). At 1 month, nystagmus intensity decreased in 62.5%, but increased in 32.5%. No side effects were documented. Conclusion: Azopt eye drops significantly reduced nystagmus in infants and children, without side effects. Worsening of nystagmus was, however, noted in around one-third of the cases, so close follow-up is essential for timely discontinuation.