Contact Us

Contact Us

Prof. Zakia Sultana Shahid
Phone: +8801711368788
Email: [email protected]

Address:
Bangladesh Glaucoma Society
House no. 12/A, Road No 5, Near (Harun Eye Foundation),
Dhanamondi,
Dhaka 1205

frequently asked questions

The eye works as a camera; it has lenses, a diaphragm and a film. The cornea e and the crystalline lens are the parts that function as focusing lenses. Between them we find the iris, the coloured part of the eye that varies from person to person. At the center of the iris there is the pupil (diaphragm), which adjusts to admit more or less light. Thanks to the cornea and the crystalline lens (lenses), the image is sharply focused on the retina (film). The retina lines the posterior chamber of the eye, which is filled with a gelatinous substance known as “vitreous body”. Light passes through the cornea, pupil, crystalline lens and vitreous body and hits the retina, thus generating the visual stimuli. The visual stimuli are then transformed into electrical impulses and carried through the optic nerve to the brain, which interprets them by shaping the images. Any alteration affecting one or more of these parts results in a defective perception of the images.

Intraocular pressure (IOP)

The eye behaves like a semielastic ball filled with constantly circulating fluids. If the amount of fluid produced does not equal the amount reabsorbed, there is a fluid surplus. Just like in a balloon that is too inflated, this causes an increase in the internal pressure. Thus, the internal pressure of the eye, or intraocular pressure, corresponds to the tension of the eyeball. The fluid flowing inside the eye, which is responsible for the intraocular pressure, is known as the “aqueous humour”.

The aqueous humour is produced behind the iris and flows forward through the pupil; the drainage channels of the aqueous humour are just next to the internal angle between the cornea and the anterior face of the iris. Obviously, they are not visible with the naked eye but may be compared to a microscopic filter located right at the bottom of the angle, in a sort of drainpipe, beyond which the drainage channels direct the flow through the wall of the eyeball where the fluids are reabsorbed. The aqueous humour, in fact, has nothing to do with the formation of tears.

Glaucoma is a disorder of the optic nerve, which is usually damaged by excessively high intraocular pressure. The optic nerve is similar to a transmission cable connecting the retina to the brain and is composed of a bundle of filaments known as “nerve fibres”: more than a million for each eye. The point where this cable connects to the rear part of the eye is known as the “papilla” or optic nerve head. The health of the papilla depends on the circulation of blood and nutrients. This is slowed down and inhibited when the ocular pressure becomes too high. Each fibre of the optic nerve carries a part of the visual message from the retina to the brain, where the images of our surroundings are formed. The “visual field” is the whole image that we can see without shifting our gaze.

Glaucoma

Causes and effects

When, because of glaucoma, the fibres of the optic nerve become damaged, some areas known as “scotomas”, where it is no longer possible to see, appear within the visual field. Initially very small, the scotomas are noticed only when they become bigger and there is already extensive damage to the optic nerve. In the meantime, the patient will continue to see clearly at the centre. In the final phases the optic nerve is completely destroyed and blindness occurs. It is for this reason that it is essential to diagnose the glaucoma as early as possible. How many different types of glaucoma are there?