Introduction
Glaucoma is a group of eye diseases that damage the optic nerve, usually due to increased intraocular pressure (IOP). It causes gradual, painless, and irreversible vision loss, often without noticeable symptoms until advanced stages. Unlike cataracts, vision lost from glaucoma cannot be restored.
Early Stage (Silent Stage):
- No Symptoms: Most people are unaware they have glaucoma at this stage, especially in primary open-angle glaucoma (POAG).
- Normal Central Vision: Vision remains sharp and clear initially.
- Mild Peripheral Vision Loss: Very subtle blind spots in the outer (peripheral) field of vision—usually unnoticed without formal visual field testing.
Moderate Stage:
- Tunnel Vision Begins: Peripheral vision begins to narrow like looking through a tube or tunnel.
- Difficulty with Low Light and Contrast: Reduced ability to adapt to darkness or changes in lighting; objects may blend into the background.
- Bumping into Objects: Patients may begin to misjudge distances or bump into doorways or obstacles on the side.
Advanced Stage:
- Severe Tunnel Vision: Only a small central area of vision remains. The visual field is severely restricted.
- Activities Affected: Reading, walking, and recognizing faces become difficult. Driving becomes dangerous or impossible.
- Monocular Progression: Glaucoma often affects one eye more than the other, so some people rely on their better-seeing eye—masking the extent of vision loss.
End Stage (Blindness):
- Complete Vision Loss: The central vision eventually disappears, leading to total blindness.
- Optic Nerve Atrophy: On examination, the optic disc appears pale and deeply cupped (optic disc cupping).
- Permanent Damage: Vision lost at this stage is irreversible because the optic nerve fibers are destroyed.
Progression Pattern:
- Slow in POAG: Gradual over years or decades. By the time it’s noticed, significant damage has often occurred.
- Fast in Angle-Closure Glaucoma: Can be sudden and painful, with rapid loss of vision if not treated urgently.
- Congenital and Secondary Glaucomas: Can progress rapidly in children or due to trauma or other eye diseases.
Summary Table:
| Stage | Visual Symptoms | Description |
| Early | None or slight peripheral loss | No pain, vision seems normal |
| Moderate | Tunnel vision, poor contrast | Peripheral narrowing, bumping into objects |
| Advanced | Only central vision left | Tunnel vision, central “pinhole” sight remains |
| End Stage | Total blindness | Complete loss of sight, irreversible |
Causes of Glare While Driving at Night
Introduction
Glare during night driving can make it difficult to see clearly and increases the risk of accidents. It is caused by various factors related to both eye health and environmental conditions:1.