Optic Disk Pit

Dr Ben Wild

Overview

Our vision comes from light waves stimulating retinal photoreceptors and these photoreceptors transferring their signals through a multitude of other cells to the ganglion nerve cells. These ganglion cells bunch together and form the optic nerve. The optic nerve then sends the signal to the occipital lobe in the brain where vision is interpreted and recognized.

An image of a healthy retina and optic nerve.

Occasionally, one (85% of cases) or both (15% of cases) optic nerves do not develop properly at birth. These poorly grown nerves tend to be much larger in size but have a large hole in the middle. Optic pits do not usually affect the development of vision in any way but can lead to central retinal detachments from fluid entering the hole and seeping underneath the retina. It can also lead to glaucoma-like blind spots with age. Retinal detachments due to optic disk pits occur by the age of 30 fifty percent of the time.

An image of a healthy retina and an optic nerve disk pit.

Signs and Symptoms

Signs

Gray hole in the optic nerve.

Symptoms

None until a retinal detachment occurs (painless central vision loss).

Causes and Risk Factors

Causes

Congenital anomaly (born with this condition).

Risk Factors

No known risk factors.

Prevention and Treatment

Prevention

There are no known preventative measures.

Treatments

· Use an AMSLER grid daily to monitor for metamorphopsia (distorted central vision).

· Laser photocoagulation to create scar tissue between the retina and nerve so that a retinal detachment cannot occur.

· Vitrectomy surgery to remove the vitreous gel inside the eye to eliminate the “pulling force” and lower the likelihood of a retinal detachment.

Prognosis

Prognoses vary wildly depending on the location and size of the optic nerve pit. Small pits usually do not lead to any defects whereas large pits that lead to retinal detachment usually progress to a state of blindness without treatment. Surgical intervention before retinal detachment has greatly lowered the likelihood of retinal detachment.