Cataract and Glaucoma

Cataract and glaucoma are two eye diseases that are quite common among elderly people. If you take action early on in the disease, both cataract and glaucoma are very well treatable. If you start treatment too late or not at all you will go blind and eventually stay blind. In the following article you can read everything you need to know about cataract and glaucoma.

Cataract

When somebody is suffering from cataract, they have a problem with their eye lens. As the disease progresses, their eyesight will reduce as a result of their lens becoming cloudy. When action is taken too late or not at all, a person can become blind because the lens of the eye will have become completely opaque.

The facts

• To this day (2010) about 40 million people worldwide are blind in one or both eyes. Half of these people (17.5 million) turned blind as a result of cataract.
• About half of all people between 50 and 65 years old show signs of cataract. Most of these people however, notice it either very little or not at all.
• 70% of the world population has cataract around the age of 75. Some only starting, some in a progressed state.
• People suffering from diabetes often get a type of cataract at a much younger age.

Discovering cataract

Cataract is usually discovered at a later age and the most common symptom is blurry eyesight (especially when looking into light). Seeing double with one eye is another common symptom of cataract. A third possibility is that, for example, a person of 60 years old, who has worn glasses for several years, starts noticing differences when looking far away and reading. This person may suddenly be able to read the paper again without the glasses he or she needed before. This phenomenon is also often caused by cataract.

Causes of cataract

This disease, as mentioned above, is caused by the eye lens becoming cloudy. This clouding can have multiple causes, but in most cases the cause can't be found. There are doctors and scientists who claim that uv-light (ultraviolet-light), radiation from the sun, plays a part in the development of cataract, but this has never been (scientifically) proven.

In people who suffer from diabetes, increased blood sugar levels in the eye can cause an increased conversion of glucose into sorbitol (glucitol), which eventually leads to cataract. Because the membrane of the eye lens is almost completely impermeable for sorbitol and the enzyme that breaks down this substance, the sorbitol accumulates quickly in the lens. Even when the blood sugar levels of the patient return to normal, the accumulated sorbitol stays in the lens. When the blood sugar level rises again, so will the amount of sorbitol in the eye lens. This high amount of sorbitol in the lens will cause water to be sucked up into the cells to restore the osmotic balance (because of the accumulation of the sorbitol, this osmotic balance was disturbed). Apart from the fact that the sorbitol will cause water to be sucked into the cells, it also causes amino acids, inositol, glutathione, niacine, vitamin C, magnesium and potassium to be removed from the lens. All of these substances are indispensable for the lens, since they protect it against damage. The result of the removal of these substances is that the lens becomes much more sensitive to damage which will eventually lead to the proteins in the lens to become damaged, coagulate and discolour. Once this process (the damaging, coagulating and discolouring of the proteins) has started, it is considered cataract.

In a healthy eye lens the proteins are arranged according to a set pattern making the lens transparent so that we can see through it. Cataract causes this arrangement of proteins to be disturbed (see the paragraph above). The damaged proteins start coagulating in the lens which causes discolouration of the lens. First the lens will turn yellow, followed by green, orange and brown. It's also possible for white flakes to be visible in the lens, which are called opacities.

When the coagulation is only just starting (so the start of cataract) the incoming light is barely obstructed. As time passes, when the flakes become bigger and thicker, these broken proteins will start obstructing the incoming light more and more. There will be less and less light that can reach the retina and the rays of light that do pass through will be bent. When the cataract is far progressed and the lens has become completely opaque it is called 'complete cataract'. If only a part of the lens is opaque, but the rest is translucent, it is called 'incomplete cataract'.

As mentioned before, cataract can have many causes. It is, however, an age phenomenon, which means that it will affect us mostly when we get older. Usually it affects both eyes and circumstances such as trauma to the eye, diabetes and several types of medication (usually when this medication is taken for a long period of time, so chronic medication) can also be a cause of cataract.

A last cause of cataract, although very rare, is being born with it. It may for example be caused when the mother was suffering from Rubella while she was pregnant. Other problems during the pregnancy may also cause cataract in the (still unborn) child. In even rarer cases. cataract can be inherited.

Types of cataract

We can distinguish between three types of cataract:

• Nuclear cataract. These are the first symptoms.
• Cortical cataract. The first symptoms of this type of cataract is spoke-like clouding that starts at the outer rim of the eye and gradually works towards the center. When the clouding has reached the center of the eye it will be experienced as troublesome and loss of sight will occur. This type of cataract is most common among diabetes patients.
• Subcapsular cataract. This type of cataract starts with a small, dull spot in the center of the back of the lens. As time passes, this spot will become bigger and bigger. The first symptoms (complaints) will be trouble with reading and blurry outside when being outside. Subcapsular cataract is especially common in people who have or have had treatment with corticosteroids. Therefore this type of cataract is sometimes called cortisone-cataract.

Treatment of cataract

Nowadays (2010) cataract is well treatable in most cases. During the treatment the affected lens (which became opaque) will be removed and an artificial lens will be implemented. The treatment can be done by your own ophthalmologist, in your trusted hospital and usually only local anesthesia is necessary. This surgery has a very low chance of complications, although after the treatment your eye won't be capable of accommodating anymore. This means that after the surgery you will need glasses for looking close up, for example when reading. When you are going to get surgery for cataract you are usually admitted into the hospital for half a day or a full day. In 99% of the cases you can go home the same day as the surgery.

A lot of people experience fear when they hear they need surgery to one or both of their eyes, because their eyes need to be kept open during the surgery. This is, however, nothing to worry about, since keeping your eyes open is no problem. The surgeon will have a little device, which will keep your eyelids open for you, so you don't need to be afraid that you may accidently blink and cause the operation to fail. The first few days after the surgery your eyes will be a bit sensitive, but after a few days your eyes won't bother you anymore. You also don't have to worry about not being able to do anything. If both of your eyes are suffering from cataract, you will get two treatments rather than one. During the first treatment only one eye will be treated. Once this eye is fully recovered the second treatment will take place for the second eye.

Nowadays a lot of treatments are done to implement an artificial lens. Statistics from 2004 show that in that year there were a total of 80.000 cataract surgeries. In 2010 this number is higher, although the exact numbers for this year are not yet known.

Glaucoma

If someone has glaucoma there is increased pressure in the eyeball. When this is not taken care of in time, untreated glaucoma will lead to reduced vision (the typical "blind spots") and eventually, in the last stadium, to full blindness. It is also possible to suffer from glaucoma while there is no measurable pressure increase in the eyeball. When this is the case, the pressure is normal, but there is still the characteristic loss of vision that is found in people with glaucoma. This last type of glaucoma is also referred to as "normal-pressure glaucoma".

Glaucoma is most common in people over fourty and it usually progresses slowly. The vision is reduced so slowly that a patient may not always notice it immediately. Your central vision will still be fine for a long time even if glaucoma has started. This means that it is impossible to turn blind over night from glaucoma.

Causes of glaucoma

There are multiple causes for glaucoma, although increased pressure is the most important one. This increased pressure can be caused by closure of Schlemm's canal. With Schlemm's canal closed eye fluids cannot be drained properly and thus the fluids accumulate in the eye.

Glaucoma can also be inherited. In some families there are a lot more cases of glaucoma than in others.

As a result of the increased pressure in the eyeball the nerve fibers of the facial nerve slowly deteriorate. In the beginning glaucoma is barely noticeable. When it just starts it affects mostly the peripheral vision (a part of vision that often contributes little to the whole vision). The time it starts affecting the central vision is usually when it is noticed.

Someone who suffers from glaucoma can have it either in one eye, or both eyes.
 

Treatment of glaucoma

Treatment of glaucoma usually exists out of medicines aimed at decreasing the pressure in the eyeball. Once the pressure has been sufficiently lowered an increase in loss of vision can be stopped. Another medicine that's commonly used is pilocarpine (as eye drops or gel) which is designed to cause the ciliary muscle to contract. When this happens it opens the trabecular meshwork allowing excessive fluids to leave the eye. A last type of medicine that can be used are beta blockers. Different beta blockers such as timolol reduce production of the eye fluids.

When the treatment for glaucoma with medicines does not work, or work too little, one can choose for laser treatment. During this laser treatment the pressure in the eyeball will be lowered. If this laser treatment also does not work it is possible, as a last resort to choose for surgery. During this surgery an artificial drain will be created in the eye. You can also get a so called glaucoma implant.

It is necessary to mention that even when treating glaucoma the vision will never return to what it was before. This is because already existing damage can't be restored. Doctors can only try to make sure that damage to your eye or eyes does not get worse.

Sources: www.todio.nl