Intraocular pressure is determined by the balance between the production and drainage of fluid within the eye. The right method to quantify it is called Tonometry which gives the measures in mm of mercury (mmHg). For the right function of the eye and its anatomical structures is important to keep the intraocular pressure between 10- 21 mmHg.
Keeping the pressure in this physiological range is necessary to preserve the optimal anatomical conditions for refraction, and allowing a correct vision. From the physiological point of view, in fact the intraocular pressure tries to keep stable the ocular bulb shape, protecting him from deformations that can be caused from the eyelid weight and the tone of the extra ocular muscles. Also if prohibits the edema formation, by droning the waste metabolites in the bloodstream.
Different factors can influence transiently the pressure levels, like: heart rate, the consumption of alcohol and caffeine, exercise and fluid intake or some systemic or topical drugs. A pathological alteration of the eye pressure can contrariwise cause unpleasant consequences for the visual function and can occur without the patient’s knowledge.
The elevate pressure inside the eye is an important indicator in glaucoma valuation, to whom it is a risk factor. This disease in general doesn’t cause pain, or particular symptoms, but can cause characteristic alterations to the optic nerve and to the neural cells inside the retina. If glaucoma progresses and doest get the right treatment, it can influence the peripheral vision and cause irreversible damages to the optic nerve that can cause even blindness.
In most cases the pressure is harmful if it’s more than 21 mmHg, but some patients can suffer adverse consequences with a lower intraocular pressure (normal-pressure glaucoma). On the contrary some people can tolerate higher than normal values without significant damages to the nerve and the field of vision.
Source: Trupi dhe Shendeti