The eyeball has a volume of about 6ml. The volumetric integrity of the spherical eye is protected by the intraocular fluid (humor aqueous) in the anterior and the intraocular gel (vitreus) in the posterior. Vitreous is a static structure while aqueous is a dynamic structure. Because the deep layers of the cornea and the nutrition of the lens are provided by aqueous permeability (diffusion). Aqueous polluted with metabolic wastes and depleted nutrients must be constantly replaced with a new one. Therefore, there is a continuous secretion and drainage (absorption).
The aqueous leaves the eye through the trabecular meshwork and uveoscleral route. In problems with these pathways, absorption decreases and intraocular pressure increases.
Normally, the intraocular pressure is in the range of 10-21 mmHg. When it exceeds 21mmHg, the nutrition (perfusion) of the optic nerve deteriorates. With the involvement of the retinal nerve fiber layer, irreversible damage to the optic nerve (glaucomatous optic atrophy) occurs. In patients, peripheral vision (peripheral vision) is affected first, and visual field narrowing occurs. If the intraocular pressure is not reduced in patients, the narrowing of the visual field continues and the patient's vision becomes like looking through binoculars (tubular vision), that is, only central vision remains. If the necessary precautions are not taken, this vision also disappears over time and the patient goes to total blindness.
In order to reduce intraocular pressure, drugs that reduce aqueous production, drugs that increase absorption (drainage), drugs that reduce damage to the optic nerve (neuroprotective) are used. Sometimes single and sometimes multiple drugs may need to be used, but if the targeted intraocular pressure cannot be achieved with drugs, laser or surgical procedures may be required. Nerve fiber layer losses, visual field losses, and changes in the optic nerve head can only stop within the target intraocular pressure.
In the treatment of glaucoma, lowering the intraocular pressure is to prevent it from getting worse. Patients should be followed up with intraocular pressure monitoring, optic nerve changes, visual field evaluations, retinal nerve fiber and optic nerve head tomography.