25/03/2025
This 13 year old patient visited me for an eye exam today (image 1). He has congenital nystagmus and has been in my care since 6 years old. I have previously written about him:
https://www.facebook.com/behoptometryclinic/posts/pfbid033AfHev8u7G1Z4eAsNxZL8VYeuyLpfhnspuaJX6FLrs9bqDWpLFAispD6rf5S4jnrl
On a healthy retina, the highest concentration of cones resides on the macula (image 2a, 2b). Cones are light sensitive nerve cells that detects the smallest details of the image focused on the retina and they are also responsible for colour vision. An estimated 6 to 7 million cones can be found on the macula.
Congenital Nystagmus is a condition where the retina is underdeveloped and there is no functional macula. There are a number of causes of retina under-development but in this patient it is due to complications and lack of oxygen to the infant during birth.
When we look at an object, our eye will move so that the retinal image of that object is focused on the macula. This allows us to see the object clearly and is called fixation. However, when the macula is under- or undeveloped, the brain will keep moving the eye to find the best region of the retina to place the image on for the patient to see the clearest. So the eye will oscillate and this happens in nystagmus (images 3a, 3b).
Despite starting off with under-developed retinae (plural, singular: retina), years of wearing correctly prescribed spectacles seems to have forced his retinae to partially develop and organised itself so his acuity has improved, from 6/36 to 6/18 (third line to fifth line). His parents were naturally overjoyed with this news.
Every retina is precious and we do not give up. My mission continues... 💪
