In conjunction with World Glaucoma Week 2019, Ipoh Echo talks to Consultant Eye Surgeon Dr S.S. Gill about this “silent thief of sight.” – PART 2
Just last week, a man walked in to our consultation with poor vision in one eye only to be diagnosed with glaucoma in its advanced stage. Glaucoma, as you know, has been nicknamed the “silent thief of sight” because visual loss goes unnoticed until there is advanced visual loss. It finally results in advanced visual loss, is permanent and irreversible resulting in blindness if undetected.
What do you mean by “SILENT” or UNNOTICED LOSS OF VISION?
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 it until the disease is in its advance stage. You may wonder how can a person be ever losing vision without noticing it? Well, this is because the visual loss is from the periphery.
This vision loss is typically described as “tunnel vision” because it starts from the periphery and moves 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 which is often hardly noticed by the patient. 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 only at this stage when a significant vision loss has already occurred.
I have had patients walk into my Consultation complaining of poor vision in one eye only to be found to have advanced glaucoma. The other unfortunate thing for such a patient is that whatever vision that has already been lost cannot be reversed. In other words, 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.