Glaucoma is considered serious because it is usually detected very late. By the time it is diagnosed it would have done enough damage to the eye. The reason for the late detection of the disease is – it has very few symptoms.
The affected person does not experience many problems in his eyes except the deterioration of vision. This dimness of vision is related to the age or the common eye disease – cataract, which also occurs in the same age group between 60-70 years. The another point to note here is- the damage it causes is most of the time irreversible. The correct treatment only ensures the arrest of the further damage. It cannot restore the lost vision. Therefore it has to be diagnosed as early as possible.
MAGNITUDE OF THE PROBLEM :
The problem of the Glaucoma is more in developing countries because of the poverty, ignorance and non-systematic health system. It is estimated that one in every ten patients who visits eye hospital has glaucoma and one in every 100 becomes blind because of glaucoma in these countries. The survey conducted in various part of India indicates the prevalence of glaucoma as 14-25%, whereas the same figure in the developed countries like U.S.A. and U.K. is 12-13%.
Eye has also a definite pressure just like the blood pressure of the body.
Normally this pressure is about 10-20 m.m. of Hg. Eye surgeon suspects the possibility of glaucoma if there is any increase in this figure. Eye pressure is measured by an instrument called – Tonometer.
TYPES OF GLAUCOMA
Mainly there are three types of glaucoma.1.Open angle glaucoma 2.Closed angle glaucoma 3. Congenital glaucoma
- OPEN ANGLE GLAUCOMA
This is the most common variety of glaucoma and has got least symptoms.
This is seen both in women and men in almost equal proportions. Usually seen in the age group of 60-70 years.. The importance of this disease lies in the fact it is detected very late because it causes very few symptoms.
The main symptoms experienced by the patient are- blurring of vision, difficulty in doing the near work like reading, writing etc, the need to change the glasses frequently, the changes in the field of vision. This type of glaucoma would have usually damaged one eye and the process of damage would have started in the other eye also. The delay is also partially due to the fact that the central area of vision is preserved until the end stage of the disease. Because of all these reasons this type of glaucoma has to be diagnosed as early as possible. The following are the criteria which would help in the early diagnosis – 1. The pressure of the eyeball ( the intra-ocular pressure ) 2. The changes in the optic disc. 3. The changes in the visual field.
The changes in the visual field mainly are – the appearance of so many non-seeing areas, which means that the specific area of the optic nerve is destroyed. The other change is – the enlargement of the normally existing blind spot and the contraction of the peripheral visual field, which means that more and more optic nerve fibres are destroyed.
The exact reasons for the increase of the eye pressure are not known. But it is thought that there is some sort of blockage at the site where the aqueous liquid is absorbed to the blood.
There are many drugs which are used in the medical line of management but mainly Timolol, pilocarpine, epirine are used. But the dis-advantage of using these drugs are that they have to be used life long. So most of the time it is advised to get the surgery done, which ensures the steady maintenance of the eye pressure. Recently laser-(Non Surgical treatment)-Selective Laser Trabeculoplasty has given good results in many patients.
- NARROW ANGLE GLAUCOMA
Opposed to the previous type of glaucoma, in this type, there are many
symptoms which prompt or which bring the patients to the eye surgeon.
It is seen more in women, in 50-60 years, particularly in those who are
highly strung and anxious in disposition and usually show an instability in their vasomotor reactions.
The patient feels blurring of vision to start with, then sometimes he or she experience coloured haloes around light, mild headache may be seen occasionally. Then suddenly he or she feels severe headache, severe pain only in one eye, profuse watering, sudden acute redness of the eyes and above all patient feels sudden loss of vision in that eye. At this stage when
the patient presents to the eye surgeon, the detailed examination reveals- particular eye has become red, the vision remarkably is reduced (almost
blind) and the eye pressure (intra-ocular pressure) shoots up to the range of 80-85 mm of Hg ( very hard eyeball ).Any eye surgeon recognises this stage as emergency and takes immediate measures to reduce the eye pressure.
There is a blockage for the passage of aqueous fluid from posterior chamber to anterior chamber at the angle of the anterior chamber which is responsible for the high pressure of the eyeball. Because of this nature this type of glaucoma gets the name- narrow angle glaucoma
The initial treatment is to reduce the eye pressure by using eye drops like pilocarpine, timolol and tablets acetazolamide but if the pressure is in the range of 80, it may be necessary to use mannitol by intravenous drip for the immediate lowering of eye pressure. But whatever may be initial treatment,
the final treatment is surgery or operation. To create a passage between anterior and posterior chamber for the aqueous fluid- is the aim of the surgery. Sometimes argon laser is used to create this passage instead of surgery. Another important issue in this type of glaucoma is doing a prophylactic surgery or laser to the other normal eye even though it never showed any signs or symptoms of the disease. It is advisable to prevent the possible acute attack in the other eye, because narrow angle glaucoma is usually bilateral.
It is always advisable to lower the eye pressure to reasonably acceptable levels. If properly managed the almost blind eye regains vision appreciably. If the long term treatment is not instituted at this stage, the patient may go into this type of acute attacks twice or thrice at the interval of 2-3 months.
- CONGENITAL GLAUCOMA OR BUPHTHALMOS
Both eyes are generally affected, seen more in boys than girls. It may be detected soon after birth or later in the childhood by 3-4 years. It is due in most cases to a failure in the development of the tissues in the region of the angle of the anterior chamber. This results in the overall increase of pressure throughout the globe, with the result that the whole eyeball looks like the big eyeball of buffalo, hence the name- Buphthalmos.
The treatment of the Buphthalmos is purely surgical but most of the time it is unsatisfactory.
Glaucoma is seen sometimes as a secondary condition primary being some other disease of the eye itself.