Question
| A. |
It measures approximately 8–10 mm in diameter |
| B. |
Its colour is due to the presence of xanthophyll derivatives |
| C. |
Fovea centralis is outside macula lutea |
| D. |
None of the above |
|
Correct Answer » B Explanation |
 |
The macula lutea is a specialized oval yellow region of the central retina responsible for high-acuity vision, colour perception, and detailed tasks such as reading and recognizing faces.
The name macula lutea means “yellow spot.” The yellow coloration is produced by xanthophyll carotenoid pigments, mainly:
-
Lutein
-
Zeaxanthin
These pigments function as blue-light filters, protecting photoreceptors from oxidative damage and improving contrast sensitivity.
The macula has a high density of cone photoreceptors, which mediate sharp central vision and colour vision.
Explanation of Each Option
Option A: It measures approximately 8–10 mm in diameter
The macula lutea measures about 5–5.5 mm in diameter, not 8–10 mm.
Option C: The fovea centralis lies outside the macula lutea
The fovea centralis lies at the center of the macula lutea and represents the point of maximum visual acuity.
Option D: The macula lutea contains only rod photoreceptors
The macula contains mainly cone photoreceptors, not rods. In fact, the fovea centralis contains only cones.