**Question:** Not true about blue sclera

A. Sclera is only seen in newborns and infants
B. Blue sclera is a sign of severe anemia
C. Blue sclera is a common phenomenon in individuals with dark skin
D. Blue sclera is always associated with low oxygen saturation levels

**Core Concept:** Sclera is the white, outermost layer of the eye, primarily composed of collagen fibers and is responsible for providing structural support and protection.

**Why the Correct Answer is Right:** Blue sclera is not always indicative of low oxygen saturation levels. While it is true that reduced oxygen saturation can cause the sclera to appear bluish due to the reduced oxygen binding to hemoglobin, there are alternative reasons for blue sclera:

1. **Option A (False): Sclera is not only seen in newborns and infants:** While scleral color does change as an individual grows, blue sclera can be observed in adults as well, especially in individuals with dark skin. The melanin present in the skin surrounding the eye can scatter blue light, making the sclera appear blue.

2. **Option B (False): Blue sclera is a sign of severe anemia:** Blue sclera can be observed in anemic individuals, but it is not limited to severe anemia cases. The color of the sclera can be influenced by individual variations, skin color, and other factors.

3. **Option C (True): Blue sclera is a common phenomenon in individuals with dark skin:** As mentioned earlier, the presence of melanin in the skin surrounding the eye can scatter blue light, making the sclera appear blue. This is particularly prevalent in individuals with darker skin, as melanin concentration is higher.

4. **Option D (False): Blue sclera is always associated with low oxygen saturation levels:** While low oxygen saturation can lead to blue sclera, other factors like skin color, age, and eye pigmentation can also influence the color of the sclera.

**Why Each Wrong Option is Incorrect:**

1. **Option A (False): Scleral color changes with age:** While the sclera does change color as an individual grows, the color change is not solely determined by age. Other factors like skin color and eye pigmentation also play a significant role.

2. **Option B (False): Blue sclera is specific to anemic individuals:** Blue sclera can be observed in anemic individuals, but it is not limited to severe anemia cases. The color of the sclera is influenced by factors such as skin color and eye pigmentation.

3. **Option C (True): Blue sclera is common in dark-skinned individuals:** As mentioned earlier, the presence of melanin in the skin surrounding the eye can scatter blue light, making the sclera appear blue. This is particularly prevalent in individuals with darker skin, as melanin concentration is higher.

**Core Concepts:**

1. **Melanin scattering:** Melanin is the pigment responsible for skin color, and its concentration influences the appearance of the sclera.
2. **Color of sclera