Which condition MAINLY causes a loss of peripheral or side vision at first?CataractDiabetic retinopathyGlaucomaMacular degeneration

The condition that mainly causes a loss of peripheral or side vision at first is Glaucoma.

Explanation:

1. Glaucoma typically affects the peripheral vision first due to damage to the optic nerve. As it progresses, it can lead to tunnel vision or complete loss of vision if untreated.

2. Cataracts generally cause blurred vision, but they do not primarily affect peripheral vision.

3. Diabetic Retinopathy can cause vision loss over time but often starts with changes in central vision before affecting peripheral vision.

4. Macular Degeneration impacts the central vision primarily, leading to difficulties with tasks like reading or recognizing faces rather than a loss of peripheral vision.

Thus, the correct answer is Glaucoma.