What Causes a Macular Hole?
07 July 2019
A macular hole occurs when a small tear appears on the macula and typically affects those over the age of 60.
It is said that women have a slightly higher risk of developing a macular hole than men.
The macular itself is located at the very centre of the retina (light sensitive tissue at the back of the eye) and plays a vital role in the healthy function of sight.
The macula’s job is to keep central vision, the majority of colour vision and fine detail in check. We especially require a healthy macula for activities such as reading or driving.
When a macular hole arises, surgery is usually needed to repair it. Vision will never completely be restored, but it will be dramatically improved.
What are the stages of a macular hole?
There are three stages to the formation of a macular hole.
These are:
Stage 1: Foveal detachments — around 50% of cases will worsen without treatment.
Stage 2: Partial-thickness holes — around 70% of cases will worsen without treatment.
Stage 3: Full-thickness holes — most cases worsen without treatment.
What causes a macular hole?
80% of the eye is filled with a gel-like substance called vitreous. This works to help maintain the round shape of the eye.
The vitreous comprises masses of fine fibres that are attached to the surface of the retina. As the eye ages, the vitreous naturally starts to shrink and pull away from the retinal surface (posterior vitreous detachment). Despite how it sounds, this is usually harmless.
However, if the vitreous is firmly attached to the retina when it shrinks and pulls away, the vitreous can pull off a bit of the retina, creating a tear, known as a macular hole.
Causes of macula holes can include:
Vitreous shrinkage or separation
Diabetic eye disease
High degree of near-sightedness (myopia)
Macular pucker
A detached retina
Eye injury
What are the symptoms of a macular hole?
Most of the time a macular hole will only affect one eye; so sight loss is not necessarily noticed straightaway. Saying this, the sooner the macular hole is treated, the more sight that will be saved. A medical expert will be able to detect the formation of a macular hole.
The initial stages of a macular hole often causes blurred and distorted vision; with straight lines appearing wavy or bowed. Sufferers will also have more trouble reading small print in the first stages of the condition- true of many other conditions too.
As a macular hole progresses, some people complain of a black patch in the centre of vision. This is painless; however the missing patch of vision can be distressing.
If sudden symptoms such as flashing lights, eye floaters or dramatic fading of vision occur immediate medical advice should be sought.
What is the treatment for a macular hole?
Vitrectomy
A macular hole is often treated with an operation called a vitrectomy. The success rate of this operation depends upon the stage of the macular hole.
For patients who have had the macular hole for less than 6 months a vitrectomy has a 90% success rate. If the macular hole has been developing for over one year this decreases to a 60% success rate.
A vitrectomy is a simple procedure, during which:
- The eye is anesthetized and dilated.
- The vitreous is removed to stop it from pulling on the retina.
- A mix of gas and air is administered into the space where the vitreous had been.
- This mix creates a bubble, which puts pressure on the edges of the macular hole; to promote healing.
- The bubble then starts to fade and natural eye fluids take its place.
Post-surgery activities such as driving, reading, and exercising should be avoided for up to three days. Eye drops will be prescribed to prevent infection and reduce inflammation.
It is sometimes advised that patients lay face down for a period of time to accelerate the healing process. As tedious as this sounds, it does work wonders.
Full recovery after a vitrectomy can take anything between 4 to 6 weeks.
Ocriplasmin injection
In some cases a macular hole may be treated with an injection of ocriplasmin into the eye. An ocriplasmin injection is generally only provided in the early stages of a macular hole (stage 1 or 2).
This works by encouraging the vitreous inside the eye to part from the back of the eye, allowing the macular hole to close.
Similarly to the vitrectomy, local anaesthetic is administered prior to the injection for optimum comfort.
Common side effects include:
- Discomfort, redness, dryness or itching
- Swelling
- Sensitivity to light
- Blurred vision
Macular holes and macular degeneration
Despite their similar symptoms, macular holes and age-related macular degeneration are two separate conditions. Both are common in individuals over the age of 60.
An eye care professional will be able to distinguish the differences with various tests.
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