What is the difference between ocular hypertension and glaucoma?

The human eye and animal eye is a closed system where a certain amount of fluid is produced inside the eye at a steady rate and there is a simultaneous drainage that occurs at the same time. The system keeps a steady fluid pressure in the eye. Imagine a balloon filled with water where you have a tube on one end putting water in the balloon and a valve at the other end draining the water from the balloon. If this is kept at a steady pace, the balloon will remained filled and the pressure in the balloon will remain constant.  Now, if you partially close the drain valve, the balloon will get bigger because you have more water coming in then you have going out. The water pressure in the balloon will also get higher especially if the balloon cannot expand to accept the increased water coming in. The eye cannot expand and so the pressure in the eye goes up and that would be considered ocular hypertension which can lead to damage to the optic nerve.

A normal pressure is generally considered to be less than 20 although there are many other factors that need to be evaluated when the eye is examined.

Generally speaking, when the pressure is above 20 and no damage has occurred to the optic nerve we call that ocular hypertension. This ocular hypertension can be acute due to some active eye disease or medication or chronic and elevated all the time.

If the intraocular pressure remains elevated for a long period of time , it often causes damage to the optic nerve responsible for vision and that damage is now properly diagnosed as Primary open angle glaucoma. There is also a condition called acute angle glaucoma which we will talk about in future articles.

Primary Open Angle Glaucoma must be treated and the first line of treatment is usually an eye drop administered once a day. Ocular Hypertension is also usually treated with an eye drop although there may be cases where the patient is followed closely without eye drops depending on the cause of the ocular hypertension. Medical attention is required for both problems. POAG can require surgical intervention by laser or conventional surgery if the medications no longer control the elevated eye pressure.