Open angle glaucoma is a medical term describing a family of eye diseasescharacterized by abnormally high pressure inside the eye, optic nerve damage, and vision loss. Open angle glaucoma is sometimes called angle-closure glaucoma. Angle-closure glaucoma occurs when the drainage channels of the eye are closed, and the aqueous humor builds up and blocks the lightreceptors of the retina. This results in elevated intraocular pressure and damage to the optic nerve.
Early in the disease, there may be no noticeable symptoms, although the eye doctor may discover evidence of glaucoma damage in the shape of the optic nerve head, the way the light reflects off the surface of the eye (called the ‘reflex of the eye’), or the generalshape of the eye.
As the disease progresses, glaucoma patients have a more noticeable ‘cupping’ of the optic nerve head, and difficulty seeing at night (nocturnal vision loss). If left untreated, open angle glaucoma can lead to vision loss in both eyes, often resulting in legal blindness.
In the early stages, glaucoma patients may experience no symptoms. As the disease progresses, the patient may notice: blurred vision, especially when the light is dim tinting of the color red unilateral vision loss, which may appear to be happening on the opposite side ofthe affected eye to where the field defect is actually located, resulting in the patient mistaking this for a loss of central vision. glare when exposed to bright lights. increased sensitivity to light. the appearance of a blind spot (scotoma). blind spots that extend in size over time. impairment of peripheral vision (inability to perceive stimuli from the far periphery, causing objects to look as though they have been 'cropped'). a visual field defect (peripheral visual field constriction). when a visual field defect occurs in one eye, the patient is unaware that the other eye also has the same defect. decreased contrastOcular pain is the most common symptom of angle closure glaucoma, often felt near the back of the eye (periorbital).
Examining the eye can also help diagnose the type of glaucoma. In open angle glaucoma, the nerve fiber layer and optic disc may look healthy. In angle closure glaucoma, the nerve fiber layer may be yellow, and the optic disc may look pale.
In both types of glaucoma, however, the optic nerve is damaged. The rate of damage is determined by the pressure on the eye and the thickness of the nerve fiber layer.
In open angle glaucoma (OAG), the drainage angle of the anterior chamber is open but resistance to the outflow of aqueous humor through trabecular meshwork results in elevated intraocular pressure (IOP). The IOP elevation can slowly or quickly lead to optic nerve damage. This form is usually asymptomatic until significant damage has occurred. Primary open angle glaucoma is the most common form of glaucoma. In primary open angle glaucoma, the optic nerve damage is typically first detected in the peripheral retina, while central vision remains intact. As the disease progresses, however, the damage can be detected in both the peripheral and central retina. The exact cause of primary open angle glaucoma is not known. However, genetic inheritance, a thinner cornea, a thicker lens, and increased intraocular pressure all increase the risk of developing the disease.
Secondary open angle glaucoma occurs due to another ocular condition or a systemic disease. The most common cause of secondary angle closure is pigment dispersion syndrome (PDS), which occurs when pigment from the iris is blown into the drainage angle by pressure changes in the eye.
Many people with narrow angles will never have primary angle closure glaucoma. It is a condition where the iris is close to or obstructs the trabecular meshwork, which causes increased eye pressure and optic nerve damage.
Exfoliation syndrome occurs when normal material (called exfoliation material or lipid plaque) starts to build up and clog the trabecular meshwork. Over time, the drainage angle is blocked off and fluid does not drain as it should. Pressure increases and optic nerve damage occurs. If not diagnosed and treated, it can lead to blindness.
Exfoliation glaucoma The following text is an excerpt from the 'The Glaucoma Wiki' from the page called 'Secondary angle closure glaucoma'.
Secondary angle closure glaucoma The following text is an excerpt from the 'The Glaucoma Wiki' from the page called 'Glaucoma'.
Glaucoma Glaucoma is a disease in which the eye's optic nerve becomes damaged and vision is lost. It occurs when the fluid pressure inside the eye is abnormally high.
Idiopathic normal tension glaucoma (In English-speaking countries the term "normal tension glaucoma" is often used instead of "idiopathic normal tension glaucoma". However, some people regard "normal tension glaucoma" to be a separate disease from idiopathic normal tension glaucoma, so care is needed not to mix these two terms.) The following text is an excerpt from the 'The Glaucoma Wiki' from the page called 'Primary angle closure glaucoma'.
There are two important fluid-filled compartments in the eye. The anterior part of the eye contains the aqueous humor. This is an ultrafiltrate of the blood plasma that bathes the avascular structures of the anterior chamber. The cornea and lens are the only parts of the anterior segment that receive