Glaucoma is a common cause of blindness

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Glaucoma

Glaucoma

Glaucoma is one of the main causes of irreversible blindness on the planet. Research in developing countries suggests that over half of their populations will develop it and never receive treatment for it. However the cure rate for glaucoma in developed countries is nearly 100%.

Definition

Glaucoma is technically defined as a type of optic neuropathy. There is damage to the optic disk that is caused by pressure in the intraocular chamber of the eye. The result is narrowing of vision and then eventually the loss of vision. How serious the situation is must be determined by an eye care professional.

Glaucoma was previously thought to be a disease that had a single cause but it is now known that many factors may contribute to the deranged processes that cause the damage to the eye’s lenses and loss of vision.

Diagnosis

Glaucoma is usually diagnosed during a normal eye examination. The eye doctor uses a clinical testing tool called a slit lamp to check the condition of the eyeball and eye lenses. The differentiation of particular case of glaucoma is normally done through clinical examination.

While an eye care special examines your eye he practices --

  • Tonometry which measure intraocular pressures
  • Gonioscopy to examine the way light enters the retina
  • An analysis of nerve fibers to make sure that your connections are normal
  • Visual field examination
  • Examination of the optic disk

Tonometry

A tonometer is used to intraocular pressure (IOP). The instrument is designed to accommodate certain physical principles that are used for measuring pressure within a globe shaped entity (like your eyeball). The principle behind it is that the force required to distort the shape of a globe is directly proportional to the pressure within that globe.

There are three kinds of tonometers used by the eye care professional. These include the indentation (also known as the high-displacement) application, (or low-displacement) and noncontact instruments.

The indentation tonometers use a plunger to indent the cornea. Fluid displaced by the indentation can tell the examining eye doctor a lot about the shape of your eyeball. Conversion tables help to estimate the original IOP from the indentation tonometric value obtained so that a correct diagnosis and prescription for treatment can be made.

The applanation tonometers raise IOP only slightly to flatten the cornea. The magnitude of force required to achieve the flattening of cornea to a consistent degree is then transformed into IOP values that then help the doctor diagnose your problem.

The Noncontact tonometers use a puff of air to temporarily flatten the cornea. The IOP is calculated based on the time that it takes for the air to flatten the cornea. The results are then converted so that the proper diagnosis and prescription can be made.

Gonioscopy

Gonioscopy is performed on people suspected of having glaucoma. This procedure is performed after the anterior segment examination and IOP calculations. A gonioscope enables a doctor to view the anterior chamber angle. This tool helps determine the type of glaucoma that the person may have. An accurate diagnosis is very important to determine the right therapy.

Optic nerve and visual field diagnosis

Eye doctors that are examining you need some way of telling the extent of your damage and how fast your disease is progressing. The largesse of the damage is estimated by assessing g the status of the optic nerve and visual field by using a stereoscopic tool The doctor will look for symptoms such as notching of the rim of the lense, asymmetrical optic nerves, thinning of the neuroretinal rim (especially at the inferior and superior poles), peripapillary atrophy and leaking blood caused by splinter hemorrhages.

This examination may be conducted a few times to track the progression of the disease. It is only through serial examinations that the progression of the disease can be tracked and measured.

Nerve fiber layer analysis

A technique called red-free illumination or special photographic techniques may be used to analyze bundles of nerve fibers on the retina. This procedure detects vision loss, focal dysfunction or wedge shaped abnormalities of the lense or iris. The eyes affected will have a distinctive nerve fiber pattern that may or may not have an indentation that is characteristic of glaucoma.

Major risk factors for Glaucoma

Demographic. Age is a risk factor for glaucoma. The older you are the more likely you are to contract it.

Gender does not seem to be a factor although a handful of researchers suggest that men are more prone to getting it then women.

An enormous amount of research has confirmed that people of African, African-American, and African-Caribbean origin are much more likely to contract open-angle glaucoma (also known as POAG)

Ocular Anatomical Factors

The main precursor to developing glaucoma is intraocular pressure (also known as IOP). There ions solid evidence that IOP causes glaucoma. A high IOP indicates that a person may lose their vision more quickly.

The structure of the optic nerve head can also be a predictor of whether or not you will suffer from glaucoma. Some optic nerve structures are more prone to developing the disease than others.

If you are myopic (near sightedness) then you are at increased risk of developing POAG.

If you have Hypermetropia then you are at greater risk of developing angle-closure glaucoma

Systemic risk factors

If you have diabetes you are more likely to develop glaucoma. Systemic hypertension can also cause a raise in intra ocular pressure and therefore is thought to be a cause of glaucoma as well.

Genetic factors

Research indicates a positive family history of glaucoma is known to increases the risk of glaucoma.

Other factors

Factors like cigarette smoking, alcohol intake lack of neutrino and lack of available eye care professionals can be factors that can aggravate chances of contracting Glaucoma.

Conclusion

Glaucoma can cause severe blindness that is irreversible. This is why early diagnosis of the disease is absolutely essential. Glaucoma is a health threat that is of great concern in both developing and industrialized countries.