genetics of glaucoma

GENETICS OF GLAUCOMA

GLAUCOMA ‘The term glaucoma describes a group of disease that can lead to blindness by damaging the optic nerve.’

The human eye continuously produces a fluid, called the aqueous, that must drain from the eye to maintain healthy eye pressure. The increased pressure, called intraocular pressure, can damage the optic nerve, which transmits images to the brain.

Healthy Drainage

The front part of the eye is filled with a clear fluid called intraocular fluid or aqueous humor, made by the ciliary body. Proper drainage helps to maintain normal eye pressure.

The inner pressure of the eye (intraocular pressure or IOP) depends upon the amount of fluid in the eye.

Normal eye pressure ranges from 12 -22 mmHg. Higher pressure than 22 mmHg is considered higher than normal.

High pressure damages the sensitive optic nerve and results in vision loss. Most persons with glaucoma have an IOP measurement of greater than 21 mm Hg

Who Gets Glaucoma

Glaucoma most often occurs in adults over age 40, but it can also occur in young adults, children, and even infants. You are at an increased risk of glaucoma if you:Are over age 40Have a family history of glaucomaHave poor vision Have diabetesTake certain steroid medicationsHave had trauma to the eyes

symptoms of glaucoma

Seeing halos around lightsVision lossRedness in the eyeEye that looks hazy (particularly in infants)Nausea or vomitingPain in the eyeNarrowing of vision

Types of glaucomaThere are several types of glaucoma.

Open angle glaucomaAngle closure glaucomaNormal tension glaucomaSecondary glaucomaCongenital glaucoma

Open-angle glaucoma

Open-angle glaucoma, the most common form of glaucoma, accounting for at least 90% of all glaucoma cases:

Is caused by the slow clogging of the drainage canals, resulting in increased eye pressureHas a wide and open angle between the iris and corneaDevelops slowly and is a lifelong conditionHas symptoms and damage that are not noticed

Open-angle” means that the angle where the iris meets the cornea is wide and open

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Angle-closure glaucomaAngle-closure glaucoma, a less common form of glaucoma:

Is caused by blocked drainage canals, resulting in a sudden rise in intraocular pressureHas a closed or narrow angle between the iris and corneaDevelops very quicklyHas symptoms and damage that are usually very noticeableDemands immediate medical attention

angle between the iris and cornea closed. Poor drainage is caused because the angle between the iris and the cornea is too narrow and is physically blocked by the iris. This condition leads to a sudden buildup of eye pressure.

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Normal-Tension Glaucoma (NTG)

Also called low-tension or normal-pressure glaucoma. In normal-tension glaucoma the optic nerve is damaged even though the eye pressure is not very high. it is still unknown why some people’s get damaged their optic nerves even though they have almost normal pressure levels.

Secondary glaucomaIt develops as secondary to, or as complications of, other conditions, including:

cataractsdiabeteseye trauma eye surgeryor tumors

Congenital glaucoma

Congenital glaucoma — also referred to as Childhood glaucoma or infantile glaucoma — occurs in babies and young children. It is usually diagnosed within the first year of life.This is a rare condition that may be inherited, caused by incorrect development of the eye’s drainage system before birth. This leads to increased intraocular pressure, which in turn damages the optic nerve.

DiagnosisGlaucoma is detected through a comprehensive dilated eye exam that includes the following:

Visual acuity test: This eye chart test measures how well you see at various distances.

Dilated eye exam: In this exam, drops are placed in your eyes to dilate, the pupils. A special magnifying lens is use to examine your retina and optic nerve

Tonometry: it Is the measurement of pressure inside the eye by using an instrument called a tonometer.

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Pachymetry: IS the measurement of the thickness of your cornea. a numbing drop is applied to your eyes and an ultrasonic wave instrument is use to measure the thickness of your cornea.

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Visual field test: This test measures your peripheral (side vision). The lost of peripheral vision is a sign of glaucoma.

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Glaucoma treatmentsGlaucoma treatment may include:

prescription eye drops laser surgery microsurgery

prescription eye drops: These either reduce the formation of fluid in front of eye or increase its outflow. laser surgery: Laser surgery for glaucoma slightly increases the outflow of the fluid from the eye inopen-angle glaucoma or eliminates fluid blockage in angle-closure glaucoma.

microsurgery: In an operation called a trabeculectomy, a new channel is created to drain the fluid, thereby reducing intraocular pressure that causes glaucoma

Glaucoma facts

Glaucoma is a leading cause of blindness

There is no cure (yet) for glaucoma

Everyone is at risk for glaucoma

There may be no symptoms to warn you

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