Q. 1 – Regarding blood vessels and the presence of a retinochoroidal coloboma the following is/are true
- There are no blood vessels in the intercalary membrane
- There blood vessels are present in the intercalary membrane
- The blood vessels in the intercalary membrane may be closed.
- One should be cautious in preserving the blood vessels in the intercalary membrane during retinal surgery.
Q. 2 – Regarding the Retino-choroidal coloboma the following is/are true.
- The coloboma involves the choroid
- The coloboma does not affect the inner retinal layers structure
- The coloboma is associated with lack of the Bruch’s membrane
- The intercalary membrane maintains the retinal architecture of the inner retinal layers.
Answer 1: The correct answer is 2, 3, and 4. (2) There are blood vessels present in the intercalary membrane which are seen to cross the coloboma. They are easily seen clinically as in our case and also on OCT. (3) While the major blood vessels may remain open, there may be closure of small blood vessels, such that only their silhouette is seen. (4) It is important that the blood vessels that are visible may not be sacrificed during retinal surgery, specially since they may be relatively larger vessels. Further the circulation of the intercalary membrane is not so good. Therefore further ischaemia may lead to the risk of developing more holes in the future.
The correct answer is. 1 and 3. (1). the coloboma involves the choroid and there is loss of choroid which is easily visible in the OCT. (3) The coloboma is not restricted to the choroid and also involves the Bruchs membrane, retinal pigment epithelium and the photoreceptor layers. This can be easily seen in our patient. (1,3) The inner layers of the retina are also affected. Thus the normal architecture of the inner retinal layers can be seen to be lost in the area of the coloboma, where the bridging membrane is called the intercalary membrane.