Pseudo-Exfoliation Syndrome and Glaucoma
In some eyes with raised intra-ocular pressure and glaucoma, many tiny white flakes can be seen when viewed through a slit lamp microscope, lying on the edge of the pupil, and on the front surface of the crystalline lens. These white flakes have the appearance of microscopic dandruff and are usually accompanied by a mild dispersion of pigment granules from the back surface of the iris, with accumulation of this pigment in the tissues of the trabecular meshwork. This is different from a condition called pigment dispersion syndrome. About 50% of the time, only one eye of a patient is affected by the pseudo-exfoliation syndrome.
This deposit of white flakes and pigment granules on the trabecular meshwork interferes with the drainage of aqueous fluid from the inside of the eye to the blood vessels on the surface of the globe. The eye pressure then rises. It may do so rapidly and to very high levels. If this occurs damage to the optic nerve fibres and thus to the vision, may occur rapidly.
For this reason, any eye with pseudo-exfoliation syndrome is at risk of developing glaucoma, even if the pressure has not risen at the time the condition is first detected. All eyes with pseudo-exfoliation, even with normal pressure, need to be checked by an ophthalmologist regularly. The patient does NOT feel a rise in pressure, and it is only by pressure testing that it can be detected. It would be tragic for loss of vision to occur because an increase in pressure remains undetected as a result of a lack of regular checking.
If the eye pressure does rise, treatment aims to lower the pressure to prevent the onset of glaucoma or prevent it getting worse. In the first instance, this is usually with either medical treatment or a procedure called selective laser trabeculoplasty (SLT).
With medical treatment, one or more types of drops are used to slow down the pumping of aqueous into the eye, or to speed up its drainage. Often, however, pseudo-exfoliation glaucoma is resistant to medical therapy. Fortunately, this condition responds to SLT about 85-90% of the time, compared with a 70-75% response rate of "ordinary" glaucoma to this type of laser. In some eyes, the pressure-lowering effect of the laser (with or with-out eye drops) can last for many years.
If SLT and/or medical treatment fail to control eye pressure, then drainage surgery, similar to that for other types of glaucoma, can be employed. The success rate for surgery is the same as for other forms of glaucoma - about 80-85%, unless there are special complications applicable to a particular eye.