Hypotony is defined as low intraocular pressure (IOP) and occasionally is associated with decreased vision. Normal IOP is usually between 10 and 20 mm Hg. Similar to using inches as a way to report length, mm Hg refers to millimeters of mercury and is a way to report pressure. An eye can be considered to have hypotony when the IOP drops below 10 mm Hg. Hypotony has several causes. The most common are chronic inflammation within the eye, or retinal detachment. This clinical sign is difficult for the average person to detect, the ophthalmologist uses specialized instruments to measure the intraocular pressures. This condition is treatable, contact us today for your pets complete ophthalmic examination today.