All experiments described here were approved by the University of Waterloo Animal Research Ethics Committee and adhered to the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. Male Brown Norway rats (n = 15, Harlan Laboratories, Inc., Indianapolis, IN, USA), weighing ∼300 g, were dark adapted for at least 12 hours in a 12/12 light cycle room prior to the experiment. The rats were transferred from the animal room to the research lab in light-isolated cages, and all animal procedures except for the OCT+ERG data acquisition were conducted under a dim, red headlight (631 nm, <10.9 lux). The rats were anesthetized with 200 μL/100 g ketamine/xylazine cocktail (0.75 mL ketamine + 0.5 mL xylazine + 0.75 mL sterile water) through intraperitoneal injection (IP), followed by a 5 mL saline IP injection to keep the body hydrated. One drop of topical anesthetic (0.5% proparacaine hydrochloride, Alcaine; Alcon, Mississauga, ON, Canada) was applied to each eye, followed by one drop of tropicamide (Alcon) for pupillary dilation. To keep the cornea properly hydrated and therefore optically transparent, artificial tears were applied to both eyes every ∼5 minutes. The rats were separated into two groups: OCT+ERG recordings were collected from 11 rats before, during, and after IOP elevation. Systemic blood pressure was measured from the remaining four rats with a CODA surgical monitor (Kent Scientific, Torrington, CT, USA) before, during, and after IOP elevation for the same duration as for a regular OCT+ERG recording session. For the OCT+ERG imaging procedure, the animals were placed on a custom stereotaxic holder that includes a bite bar, a nose bar, and ear bars, designed to minimize head motion caused by breathing. The base of the animal holder was lined with an electrical thermal pad kept at 38°C, and the animal temperature and breathing rate were monitored every ∼10 minutes. Metacam (0.2 mL/100 g body weight diluted in sterile water) was administered for pain relief after completion of the experiments to help with the animal recovery.