The pressure that the fluid in the eye places on the eyeball is called eye (or intraocular) pressure. Pressure that is either too high or too low can lead to vision loss.
Normal Eye Pressure
According to Glaucoma Research Foundation, normal eye pressure is usually between 10 and 20 mmHg (millimetres of mercury).
Low Eye Pressure
According to Duane's Clinical Ophthalmology, although low eye pressure (also called hypotony) refers to pressure below the normal range, the condition does not have a strict definition. In general, pressure of less than 6 mmHg can have adverse effects on the eyes.
Causes
According to Dr. Elliot Werner, most hypotony occurs as a side effect of eye surgery that causes a leak in eye pressure, but sometimes inflammation or poor blood flow can cause hypotony. A detached retina can also cause hypotony.
Symptoms
The main symptom of low eye pressure is decreased or distorted vision, although you may also experience pain.
Treatments
Treatments for low eye pressure caused by surgery include patching, placing an oversized contact lens in the eye, injecting blood to promote scarring, suturing techniques or using a substance called viscoelastics to help reshape the front inner part of the eye. Treatment for chronic inflammation may be with topical and/or oral corticosteroids.