Abstract
Purpose:
To assess the relationship between acute elevations of intraocular pressure (IOP) and visual contrast sensitivity in mice.
Methods:
Baseline scotopic and photopic contrast sensitivities were determined on peak spatiotemporal frequency (spatial frequency = 0.08 cyc/deg; temporal frequency = 2 deg/sec; speed = 25 cyc/sec) for five (5) c57Bl6 female mice with an established optokinetic-based technique. IOP was then elevated experimentally in one eye via a single anterior chamber injection of highly cohesive sodium hyaluronate (Healon 5, Abbott Medical Optics, Inc.). After post-operative measurement of IOP with a rebound tonometer (Tonolab) mice were immediately dark-adapted. Following two hours of dark-adaptation contrast sensitivity was assessed with the same technique under scotopic and then photopic conditions. IOP and contrast sensitivity were sequentially measured on post-operative days 1, 2, 3, 4, and 6. T-tests and repeated measures ANOVAs with cutoffs of p < 0.05 were conducted in SPSS version 21 (IBM).
Results:
IOP is elevated to approximately 35 mmHg following a single injection of sodium hyaluronate but decreases to baseline after about 2 days. When IOP is elevated, both scotopic and photopic contrast sensitivities are markedly reduced. Both scotopic and photopic contrast sensitivities recover as IOP normalizes. There is a mild delay in both scotopic and photopic contrast sensitivity recovery which is more prominent under photopic conditions.
Conclusions:
Acute IOP elevation results in decreased scotopic and photopic contrast sensitivity in mice. IOP normalizes faster than contrast sensitivity recovers.
Keywords: 478 contrast sensitivity •
568 intraocular pressure