By Dr S.S. Gill
In conjunction with World Glaucoma Week 2020, Ipoh Echo talks to Consultant Eye Surgeon Dr S.S. Gill about this “silent thief of sight” – PART 2.
The “silent thief of sight” is the nickname that has been given to glaucoma. This notorious disease results in permanent irreversible blindness in the affected eye(s) that often goes unnoticed until the loss of vision is advanced. Why is it referred to as “SILENT” or an unnoticed loss of vision? Well, In some types of glaucoma such as Primary Open Angle Glaucoma and Normal Tension Glaucoma, the visual loss occurs very slowly without the patient ever noticing until the disease is in its advance stage. You may wonder how can a person be losing vision without noticing it? Well, this is because the visual loss is from the periphery and moves on slowly to a central total loss of vision. Furthermore, glaucoma is “silent” because it does not cause any acute pain or symptoms.
This picture simulates the early tunnel vision that a glaucoma patient may experience. A major part of the central vision is good and the patient is still able to see well. The loss of vision noticed around the periphery can only be detected by specialised testing known as Perimetry or Visual Field Testing.
This picture shows advanced glaucoma. Most of the peripheral vision has been lost here. Only a small tunnel of vision is left. At this stage, the patient usually experiences difficulty moving around in poorly lit places or outdoors at night. Many people end up seeking treatment at this stage when a significant vision loss has already occurred. The TUNNEL VISION then finally progresses to COMPLETE BLINDNESS in the end-stage.
I have had patients walk into my Consultation complaining of poor vision in one eye, where upon checking, were found to have advanced glaucoma. This happens in cases where regular eye checks have not been the norm until such advanced symptoms have come about. The other unfortunate thing for such a patient is that whatever vision which has already been lost cannot be reversed. In other words, this vision loss is permanent. It is for this reason that those above 40 years of age should have their eyes checked routinely as part of their general health screening.
More on Glaucoma tests in the next issue of the Ipoh Echo.