Diagnose My Retinal Photograph: Myelinated Nerve Fiber Layer6:54 PM
Today's retinal photograph of note shows a fluffy white lesion located in the retina, fanning off near the optic nerve. Below is a classic appearance.
Myelinated Nerve Fiber Layer:
Studies show that myelinated nerve fiber layer is very rare (less than one percent of the population!). The presence of myelin within they eye would occur during gestation, so this is something that you would be born with and would not change in any way as you go through life. Common differential diagnoses include inflammatory or ischemic changes in the eye, like cotton wool spots or edema, but these changes would be acute conditions and would not exist consistently since childhood.
What this Means to Me
Because myelin blocks the underlying retinal cells, there can be a possible loss of vision associated. For most people, the changes would be of limited consequence such as an enlarged blind spot on a visual field test (the nerve is naturally a blind spot because there are no retinal photoreceptors in that area). I would expect the patient above to have an enlarged blindspot due to the close proximity of the myelin to the nerve. In more severe cases, a larger area of myelin could cause more significant visual disruption and even be associated with strabismus (an eye turn).
It is unusual but possible to develop myelinated nerve fiber layer changes after birth in cases of ocular tumors or trauma, but this is exceedingly rare and a result of a disruption to the normal ocular tissue.
If you have myelinated nerve fiber layer, your doctor will definitely talk to you about this finding (even though it is normal) because it is permanent inside of your eye. If you see a new doctor in future it will help them know that this is normal for you and not an acute event (like a cotton wool spot) if there was some question. If you are a suspect for glaucoma in any way (high pressures, suspicious anatomy, family history) then it would be a good idea to establish a baseline visual field test to map the area of defect associated with your myelinated nerve fiber layer. Glaucoma causes progressive visual field loss, and it is helpful for your doctor to know what a normal field looks like for you in order to track changes with time.
images in this post are provided by eyedolatry