Clinical studies continue to find glaucoma to be the handiwork of more than just intraocular pressure alone; blood pressure and ocular perfusion pressure are also at play. Although researchers found patients with glaucomatous optic neuropathy (GON), based on the presence of optic nerve damage and visual field defects, had significantly lower 24-hour and nighttime diastolic blood pressure (BP) levels than those without, they also realized the damage was not related to average blood pressure.

After studying 185 eyes, 19 of which had GON, they instead found that extreme decreases in systolic and diastolic BP at night—defined as a more than 20% decrease compared with daytime measurements—were significant risk factors for glaucomatous damage.

“In this population, the link between nocturnal BP and GON is determined by extreme dipping effects rather than low nocturnal BP levels alone,” the researchers concluded. “Further studies considering extreme decreases in nocturnal BP in individuals at high risk of glaucoma are warranted.”

Melgarejo JD, Lee JH, Petitto M, et al. Glaucomatous optic neuropathy associated with nocturnal dip in blood pressure. Ophthalmol. 2018;125(6):807-14.