GLAUCOMA RISK FACTORS

GLAUCOMA RISK FACTORS

Glaucoma Is the silent thief of sight group of disorders that have certain common features:

  • Characteristic visual loss; and
  • Often, but not invariably, increased Intraocular Pressure (IOP)

Glaucoma Risk Factors

  1. High Intraocular pressure.
  2. Family History.
  3. Trauma( Ocular/Head injury)
  4. Increasing Age
  5. Race

Explanation of the risk factors

Glaucoma Risk Factors

 

  1. High Intraocular pressure

If one pumps water into a tank, at some point, when the tank is full, it begins to overflow. If there is no mechanism to allow for free flow of the water, the tank could give way.

Normally pressure of the eyes vary from time to time throughout the day (diurnal variation) with peak pressures at around 3am-5am. As the pressure begins to rise for a sustained periods of time, it may begin to cause severe pains and blurred vision. In some forms of glaucoma, it can cause severe headaches.

High intraocular pressures, radiate to the back of the eyes, where it begins to compress the nerves, suffocating the nerve cells.

Gradually the nerve fibres begin to die, If left uncontrolled, the death of the nerve fibre progresses more quickly. Any Optic nerve fibre that dies cannot regenerate. Hence, the areas of vision controlled by the dead fibres, are also lost. ( Glaucoma, the thief of sight)

 

  1. Family History:

Everyone is at risk for developing glaucoma, but you may be at increased risk due to family history .Studies have found that open-angle glaucoma, which accounts for 90 percent of glaucoma cases, is part hereditary. If members of one`s family have glaucoma, same person is at a higher risk than the rest of the population. Family history increases risk of glaucoma 4 to 9 times.

If glaucoma is detected in any member of a family, it is highly recommended that other members of the family be screened early to detect and prevent loss of vision.

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"Glaucoma Risk Factors"

  1. Trauma

Any penetrating injury or blow to the eyes orinvoles head and/or eye socket can directly affect the optic nerve cells or indirectly cause pressure within the eye to build up and damage the nerve cells.

  1. Increasing Age

One may wonder why the risk of glaucoma increases with age. One explanation is that, with increasing age, we lose trabecular cells, which has a role in keeping the trabecular meshworks functioning well.

One may also ask the opposite question…”why are babies born with congenital glaucoma?, in this case ,there might be abnormal development of the trabecular meshworks, such that it does not function properly. Clearly , the trabecular meshworks plays a very important role, hence glaucoma is refered to as “trabecular meshwork disease”, by some investigators.

From age 40 and above, the risk of developing glaucoma increases.

 

  1. Race:

Blacks are at higher Risk of developing glaucoma than Caucasians (white). Africans and Hispanics may be particularly susceptible to damage from poor blood flow to the optic nerve because there is a high prevalence in this population of diseases that affect the blood vessels, such as diabetes. Also as with African Americans, thinner corneas also increased the risk of glaucoma in Hispanics

"Glaucoma Risk Factors"

Other Risk Factors include

  • Prolonged use of corticosteroids (steroid responders),
  • Medical conditions- Specific conditions like diabetes, hypertension, nearsightedness, farsightedness,eye tumor can place one in a high risk category.. Hypertension 3. Diabetes

When there is increased blood pressure, there is also an increase in the rate of production of aqueous. And as more aqueous is being produced, it puts a strain on the drainage canal ( trabecular meshwork). Also, low blood pressure is also potentially a risk, due to poor perfusion of the Optic nerve.

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Also, very high blood pressure can result in a stroke; blood clots (emboli) can be lodged anywhere, even on the exit of blood vessels lieing side by side with the Optic nerve

 

Types Of Glaucoma ( broad grouping).

  1. Open Angle Glaucoma.
  2. Angle- Closure Glaucoma : Usually associated with very severe eye pains and headache
  3. Normal Tension Glaucoma.
  4. Congenital Glaucoma.

Other sub forms, fall under either 1. or 2. Above

Normal-Tension Glaucoma (NTG)

Also called low-tension or normal-pressure glaucoma. In cases of normal-tension glaucoma, here the optic nerve usually gets damaged notwithstanding that the eye pressure is not too high. The reason for this damage is still unknown notwithstanding that the pressure levels is normal.

 

"Glaucoma Risk Factors"

 

Ocular Hypertension (OHT)

OHT is a sustained increase in the pressure of the eyes with no damage to the Optic Nerve head or visual field loss ..... But, OHT over time can lead to Secondary Glaucoma

 

Symptoms and Signs of Glaucoma

Ø Blurred vision

Ø Loss of peripheral (side) vision

Ø Bumping into objects (in moderate to severe disease)

Ø Eye pain,vomiting, and headaches ( closed angle glaucoma)

Ø Haloes (coloured circles around light)

Ø Diminished colour perception

 

Specific test in Glaucoma include.

  1. Visual Field Testing
  2. Central Corneal Thickness
  3. Ocular Coherence Tomography
  4. Retinal Nerve Fibre layer Analysis.

 

"Glaucoma Risk Factors"

Management of Glaucoma

Treatment of Glaucoma is aimed at

  1. Reducing the production of Aqueous Humor by the Ciliary Body, and/or.
  2. Increasing Outflow of Aqueous from the anterior chamber through a natural opening or an artificial opening made surgically.
  3. Managing the coexisting medical conditions like hypetension and diabetes.
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Review of Glaucoma Cases

Case 1 : A story that illustrates a link between OHT and Glaucoma

A patient was seen recently. She was seen some couple of years ago with pressure in one eye up to 35mmHg and the other eye 9mmHg. At this point, the nerves were looking normal and vision was good She was placed on IOP lowering eye-drops, and was seen a week later. The pressure had dropped to 26mmHg and she was asked to continue with these medications. She was given another appointment. She only showed up 2years later. During loss of follow up, she had stopped the eye drops. When she came in, she had lost vision with the nerve completely ravaged, and pressure on same eye up to 45mmHg. Luckily for her, the other eye is spared.

 

Case 2 : Congenital Glaucoma

Two Siblings age 10(male) and 14(female) came in on their first visit for a Routine Eye Check. Both of them needed prescription glasses to aid their vision at far. After examination, their eyes looked suspicious for Glaucoma . Their eye pressures were checked, and it showed IOP of 37mmHg and 40mmHg respectively. A diagnosis of Developmental Glaucoma was reached. They were placed on two different eye-drops, pressure still not lowered. Medications were switched, and there was improvement. They got refill of their eyedrops monthly. After a while, they got tired and for 3months they never came for follow up visit. Calls were put to the parents, as a matter of urgency, to bring the kids in. It took a very detailed, graphical/pictorial counselling to convince the kids on the need to continue medications, but of course, compliance is always a problem with management of Glaucoma patients

 

"Glaucoma Risk Factors"

 

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