What Is a Macular Hole?
Our sense of sight is made possible by a thin, multi-layered tissue that lines the back of the eye known as the retina. The retina contains photoreceptor cells, which are highly specialized neurons that are sensitive to light. The retina contains two types of photoreceptor cells: rods and cones. When light enters the eye, it activates the rods and cones and translates the luminescent signals into neural impulses, sending them along the optic nerve to the visual cortex of the brain. The brain interprets the neural impulses and organizes them into cohesive images, thus creating our sense of sight.
Each of the different types of photoreceptors has specific functions. Rods primarily handle our eye’s ability to see in low-lighting conditions, while cones are responsible for our visual acuity and color vision. The center of the retina, known as the macula, has the highest concentration of cones, making it the seat of our eye’s central vision capabilities. Any time you read, drive, or look at an object’s fine details, you’re engaging the macula.
When the macula experiences some kind of strain, the tissue can weaken and begin to tear, leading to a macular hole. Macular holes are small breaks in the macula that impair our central vision. They are most commonly caused by tractional pulling from the vitreous humor, but can also be caused by traumatic injury and macular edema (i.e. swelling of the macula).
As we age, it’s natural for the vitreous humor to diminish, lose its viscosity, and shrink away from the retina. This can occur without noticeable changes to your vision. However, in some cases, your vitreous may be unusually sticky and become adhered to the macula. Because it is so adherent to the retina, the vitreous is unable to make a clean break as it shrinks away. As it pulls at the retina, it can strain the macular tissue and eventually cause a tear or hole to form. While this is the most common cause of macular holes, they can also be caused by traumatic injury and severe cases of macular edema (i.e. swelling of the macula).
Macular Hole Symptoms
Like most other macular conditions, the primary symptoms of a macular hole include blurred vision and visual distortions (e.g. straight lines appearing wavy). If a macular hole goes untreated and continues to spread, it can eventually result in a blind spot appearing in your central field of vision. This can affect both your ability to see things that are far away as well as things that are within close proximity. However, even though your central vision is impaired because of macular damage, your peripheral vision will remain unaffected.
Macular Hole Surgery and Treatment
Macular holes are often repaired by performing corrective vitrectomy surgery. This gives the patients the best chance of improving their vision. Vitrectomy surgery involves removing the vitreous humor from the eye and relieving any traction on the macular hole edges. Afterward, the eye is filled with a gaseous bubble to help the macular hole close and heal.