Dr Ben Wild
Overview |
The retina is located at the back surface of the inside of the eye. Its main function is to detect and transmit the sensation of light to the brain for interpretation. Clinically, the macula refers to the part of the retina that represents the finely detailed central vision. For light to be detected, it must pass through the cornea, pupil, lens and vitreous humor gel before arriving at the retina and/or macula.
A frontal view of a healthy eye fundus (back of the eye) where the macula represents the darker circles.
A macular hole is a fairly common cause of central vision loss and occurs in 3 out of every 1000 people. It usually occurs due to the tractional pulling forces of the vitreous gel on the fovea (center of the macula) before or during a posterior vitreous detachment (PVD). Having had one in one eye gives the patient a 10% chance of also getting one in the other eye at a later date.
A frontal view of an eye with a macular hole (red dot).
Quickly, a PVD occurs once the vitreous gel has liquified and has shrunk enough that it separates from the retina at the back of the eye. This is a normal event that occurs once in both eyes. The separation can sometimes pull the retina so hard the retina tears or pulls the macula so hard it causes a macular hole.
Other reasons for pulling forces to exist between the gel and the macula include high levels of myopia (nearsightedness), and trauma.
Signs and Symptoms |
Signs
Red circular hole in the middle of the macula.
Symptoms
Starts as distortion in central vision (metamorphopsia). Then progresses to a blind spot in the central vision of one eye. Sometimes this can occur asymptomatically if the patient never covers the fellow eye.
Causes and Risk Factors |
Causes
Vitreous gel pulling the retina causing a hole.
Risk Factors
Female, age 60-70, vitreomacular traction from impending posterior vitreous detachment, high levels of myopia (eye is stretched).
Prevention and Treatment |
Prevention
There are no known preventative measures.
Treatments
· A partial hole is usually just observed. The majority will resolve on their own after the posterior vitreous detachment has completed.
· Vitreolysis using enzymes to digest the proteins holding the gel to the retina.
· Vitrectomy surgery to remove the vitreous gel completely and insertion of a silicone or gas bubble to push the retina together (the patient lies face down for the bubble to push the retina back together).
Prognosis |
Most partial holes resolve on their own without treatment. For macular holes requiring surgery, the hole is closed in almost 100% of cases and vison improves in 80-90% of cases. 20/40 vision or better is regained in 65% of cases. Note: 20/40 vision means letters must be twice as large as 20/20 vision.
Comentários