WHAT CAUSES GLAUCOMA?
Within the eye there is a structure (ciliary processes) which produces a clear fluid (aqueous humor). The fluid flows out through the pupil. It is then absorbed into the bloodstream through the eye’s drainage system located in the internal angle of the eye formed by the iris and the cornea. Normally, the volume of intraocular fluid is balanced between the amount produced and the amount drained. But when there is a restriction in the drainage of the aqueous humor, the fluid builds up and the pressure inside the eye rises damaging the optic nerve and causing progressive death of its fibers and loss of vision.
WHICH ARE THE DIFFERENT TYPES OF GLAUCOMA?
1- Primary Open Angle Glaucoma or Chronic Simple Glaucoma is the most common form of glaucoma (70% of glaucomas). With open angle glaucoma, the entrances to the drainage canals are clear but the aqueous humor can't drain out of the eye because drainage canals become clogged and consequently the intraocular pressure (IOP) rises. In general, these persons have high intraocular pressure. But it is also possible that a person even with “Normal Ocular Pressure” suffer visual loss with the characteristics of glaucoma. For this reason glaucoma is diagnosed not only by controlling the ocular pressure.
2- Primary Narrow Angle Glaucoma. This type is more common with hyperope patients constituting approximately 15% of glaucomas. This happens when the drainage angle is narrowed by the iris, blocking the drainage of aqueous humor and raise ocular pressure.
These types of eyes are likely to develop into an “ACUTE GLAUCOMA” where the drainage angle gets completely blocked and the aqueous humor cannot drain through the pupil. This causes a sudden raise in the IOP causing eye pain, halos around lights, nausea and vomiting. This is an emergency condition because the damage to the optic nerve may result in loss of vision within hours.
3- Congenital Glaucomas where the drainage angle was not completely formed.
4- Secondary Glaucomas, for instance due to trauma where the drainage angle is damaged.
ARE THERE SYMPTOMS TO GLAUCOMA?
There are no symptoms in 90% of glaucomas. The rare symptoms which may appear are very imprecise, such as for instance:
- Visual difficulty which is not improved completely with glasses.
- Loss of peripheral or side vision (the patient may not even notice it)
- Rainbows around lights.
WHO IS MOST LIKELY TO GET GLAUCOMA?
Certain people are at a higher risk for glaucoma.
- Persons with high ocular pressure.
- Persons with a family history of glaucoma.
- Young adults over age 35.
- Persons with thin corneas, high myopia or hyperopia, Diabetes, vascular or blood alterations, taking corticosteroids for a long time.
HOW CAN GLAUCOMA BE EARLY DETECTED?
Early detection, through regular and complete eye exams, is the key to protecting your vision from damage caused by GLAUCOMA. Controlling the IOP by itself is not enough. As a general rule, all young adults over age 35 should have their eyes examined by the ophthalmologist.
The eye exams necessary to diagnose glaucoma consist of the following tests:
- Tonometry or measurement of the intraocular pressure of the eye (IOP): this is a simple process forming part of the routine eye tests. Currently, this measurement shall be adjusted by means of the PACHYMETRY which is the measurement of the corneal thickness due to the fact that very thin corneas will show artificial low pressure readings and very thick corneas will show artificial high pressure readings.
- Fundoscopy: It allows us to observe the aspect of the optic nerve which can be photographed in order to assess more objectively its changes with time.
- Computarized Perimetry: It helps to evaluate the visual field of the patient in order to determine the functional damage of the optic nerve in detail and its evolution with time.
- Gonioscopy: It is an eye test that checks if the angle where the iris meets the cornea is open, closed or narrow.
WHAT SHALL WE KNOW ABOUT THE TREATMENT?
Although there are multiple factors which influence the progression of the damage of the glaucomatous nerve such as its irrigation, IOP, calcium metabolism, genetic factors, etc. currently it is only possible to treat the intraocular pressure.
Glaucoma is a CHRONIC DISEASE FOR WHICH THERE IS NO CURE. However with the appropriate treatment IT CAN BE CONTROLLED. For this reason it is essential for patients to be aware of the seriousness of the disease and follow the corresponding treatment.
WHAT IS THE ORDINARY TREATMENT?
The most common treatments for glaucoma are eye drops (collyriums) used from 1 to 4 times a day, depending on the case.
The medication used reduces IOP, either improving the outward flow of fluids through the drainage channels of the eye or reducing the amount of fluid in the eye.
The doctor can decide which medications are best suited for a patient based on the individual case and if the patient follows the medical instructions carefully in general the results are satisfactory.
These medications have potential side effects which might include rash, eye or eyelid redness or pigmentation, changes in the pulse and heart rate, bronchospasm, dry mouth, blurry vision, etc. The ophthalmologist shall be informed immediately if these side effects occur.
WHAT CAN WE DO IF THE TREATMENT WITH EYE DROPS IS UNSUCCESSFUL?
If the treatment with eye drops proves unsuccessful and the IOP continues there are alternative treatments:
1- Laser Treatment: the procedure is ambulatory and usually performed in the doctor’s office. It consists of the application of a laser beam over the outlet area of intraocular fluid, facilitating its drainage. This treatment only works in certain cases.
But the laser is really effective for the treatment of Acute Glaucoma. The laser makes a hole in the iris helping the recirculation of the aqueous humor and opening the drainage angle.
2- Finally, surgery is the other alternative, although it does not help to improve vision or to stop the eye drops medication. It only helps the eye drops to lower the IOP.