Introduction

A macular hole (MH) can affect peoples' vision significantly, and an epiretinal membrane (ERM) can increase the likelihood that a person will develop a macular hole. 

This article will explain the epiretinal membrane and its link to macular holes. We will also cover the risk factors of developing MH or ERM and the available treatments.

Eye structure

The healthy eye has many different parts which work together to provide good vision. The most important parts of the eye related to MH and ERM are described below.

The retina

The retina is the layer of skin inside the eye which reacts to light entering through the pupil (the black part visible on the front of the eye). The cells that react to light are called photoreceptors.¹

The macula

The macula is the most sensitive part of the retina. The macula provides central vision, as it has many photoreceptors packed into a very small space, allowing for very sharp vision.¹

Macular hole

A macular hole occurs when a hole appears in the macula.¹ This happens in 0.02%-0.33% of the population² and is more common in people assigned female at birth and those in their 60s or 70s.²

Symptoms of macular hole

Commonly reported symptoms of MH are:¹

• Difficulty reading fine print
• Straight lines (for example window frames) looking bent or wobbly
• Blurred vision
• Missing patch in the vision

If you notice any of these symptoms, you should contact your optician for an eye test straight away. 

Causes of macular hole

Certain factors can increase the likelihood that a macular hole will develop. These factors include:^{1, 2}

• If you have had bleeds in the eye
• If you have had laser eye treatment for other eye problems 
• If you have an inherited  retinal problem Changes to the eye due to diabetes
• If your macula has been swollen in the past
• If you've had eye surgery If your eye has been damaged due to high blood pressure
• If you have problems with the blood vessels providing  oxygen to your eyes
• If your retina has become detached
• Being short-sighted
• Ageing
• The eye being damaged e.g. by an accident
• Epiretinal membrane

Epiretinal membrane

Sometimes a thin film of scar tissue can grow over the macula. If this film contracts, it can tug on the macula, altering vision. Problems that people can experience with ERM include:³

• Straight lines appearing wavy or bent
• Blurred vision
• Distorted vision
• Missing central vision

If you notice any of the above symptoms, you should book an appointment with your optician immediately.

Causes of ERM

Some things that can cause ERM are:^{4, 5}

• The vitreous jelly pulling away from the retina
• Ageing
• Problems with the retina e.g. a tear or detachment
• Surgery on the eye (e.g. cataract surgery)
• Inflammation of the eye (e.g. uveitis)
• Trouble with the blood vessels in the eye

Diagnosis

An ERM will usually be diagnosed by your optician during a sight test.⁶ The tests typically used to detect either ERM or MH are listed below.

Eye examination 

Usually, your optician will be the one to detect an ERM or MH during an eye health examination.

You may have drops put in your eyes to dilate your pupils, allowing your healthcare team to have a better view of the inside of your eyes. They will ask you to read letters off a chart to understand the level of your vision and look into your eyes with a light and a microscope to assess your eye health.⁶

Optical coherence tomography (OCT)

This scan provides the healthcare professional with a detailed view of the layers that make up the retina inside the eye.⁷ It can help diagnose ERM and rule out other issues that may cause similar problems.

The OCT scan is painless and only takes a couple of minutes.⁷ Your healthcare provider will ask you to place your head in front of the machine and look at a target. You may see flashes of light or moving lines as the machine takes the measurements.⁷

Fluorescein angiography

During fluorescein angiography, a special fluorescent dye is injected into your bloodstream. Your eye is then photographed to determine if the dye leaks from the blood vessels.⁸

This test may be performed to confirm MH and rule out other conditions that could affect your vision.⁹

Treatment

If you develop an MH or an ERM that affects  your vision, surgery is usually required to improve it.^{1, 8} This operation is called a vitrectomy for an MH, or a vitrectomy and peel if an ERM is also present.^{8, 10} 

Vitrectomy

The surgery can be performed under either a general or local anaesthetic, meaning the patient can be put completely to sleep or have only the eye area numbed, depending on what their consultant deems best.¹⁰ 

A very small cut is made in the sclera (the white of the eye) and the jelly is gently separated into smaller pieces and suctioned  out of the eye.¹⁰ 

Typically, the jelly is replaced with a bubble of either gas or air. This bubble is gradually reabsorbed by your body over a few days to a few weeks, and the eye refills with a liquid called the aqueous humour.¹⁰

The eye will often be red, sore and/or swollen for a couple of weeks after the surgery.¹¹ You may also experience blurred vision for up to six weeks after the operation while the eye heals.¹¹

Risks of vitrectomy

The majority of vitrectomies are successful; however, 5-10% of people who undergo this surgery will need another operation.¹⁰

After a vitrectomy, 30-40% of people will develop a cataract, which is when the lens in the eye becomes cloudy, causing blurred vision. This can be improved with cataract surgery.¹¹

Vitrectomy and peel

An ERM is usually treated with a vitrectomy as described above.⁶

After the vitrectomy, the surgeon will gently remove the membrane from the eye, a procedure known as a vitrectomy and peel.⁶

As with a standard vitrectomy, there are some risks to the surgery. These include:⁶

• Vision remains distorted even after the ERM has been removed
• Cataracts develop more quickly after the surgery
• 1 in 50 patients needs another operation due to complications
• 1 in 50 patients find that their vision is worse after the surgery, rather than better
• Increased pressure in the eye (glaucoma)
• A 0.1% chance of a complication from the surgery causing loss of vision in the eye

After the surgery, you will be given drops to use for about one month, but you don’t usually have to stay in the hospital overnight.⁶ 

Monitoring

Sometimes, your eye health provider will recommend monitoring the eye condition rather than surgery. You can discuss this with your medical team if they think it is best for you.⁶

Differential diagnosis

Epiretinal membrane differential diagnosis

When examining you for ERM, your healthcare provider will try to rule out other causes of your symptoms. These include:¹²

• Blood vessels in the eye that are naturally more wiggly (this can be normal)
• A hamartoma (a growth that does not normally cause any problems)
• The jelly in the eye tugging on the retina
• Something else tugging on the retina

Macular hole differential diagnosis

Some conditions can look similar to or cause similar symptoms to a macular hole (MH). Your healthcare team will want to rule these out. Some of the conditions they will try to eliminate are:²

• Swelling of the macula
• Bleeding at the macula
• Macular damage due to age
• The jelly tugging on the retina
• Damage to the macula caused by the sun (often resulting from staring  at an eclipse)
• Waste products that build up in the retina over time

Living with macular hole

There are many resources available for people with vision problems caused by a macular hole. 

The macular society 

The Macular Society is a charity for people who have vision problems due to macular health issues. They hold meetings for people to connect with others experiencing the same thing, organize fundraising events, and provide information. You can check their website for help in your local area.¹² 

Low vision services

The Low Vision Services can also help to maximize the vision that people have left. This can include specialised sight testing with a registered optician, being provided with magnifiers, joining support groups, assistance from the local council to adapt home for easier everyday tasks, and much more.¹³ The RNIB website can help you find specialists in your area.

Conclusion

Macular holes and ERM can have a significant impact on vision. However, they are easily detected with modern testing and are treatable.

Even if vision is affected by MH and/or ERM, there are services that can help people live independent, fulfilling lives.