What is the normal intraocular pressure of dogs and cats?

• A. 5-15 mmHg
• B. 10-20 mmHg
• C. 20-40 mmHg
• D. 0-5 mmHg

Answer: (B)

Normal intraocular pressure in dogs and cats reflects the balance between aqueous humor production and outflow. In healthy animals, this pressure typically sits around 10–20 mmHg. This range helps keep the eye properly perfused and structurally stable; pressures above this, especially when persistently high, raise concern for glaucoma as outflow is impaired and optic nerve damage can occur. Pressures well below this range, near zero to a few mmHg, indicate hypotony, which can follow trauma, inflammation, or postoperative issues and can lead to ocular collapse or other problems. Measurements can vary with time of day, stress, and whether the animal is sedated, so interpret the value in context. Therefore, the 10–20 mmHg range is the best answer.