Introduction 

This article provides insight into the diagnosis and treatment of a macular hole, a rare eye condition that affects central vision. To provide context, I will first outline the basic anatomy of the eye, focusing on the parts relevant to this condition. Refer to the diagram on the right for a visual reference (source). 

The retina, located at the back of the eye, is a light-sensitive tissue responsible for detecting visual information and sending signals to the brain via the optic nerve. Within the retina is a specialised area known as the macula, which has a high concentration of light-sensitive cells essential for central vision. The central vision is what you use when you look directly at something, while peripheral vision refers to what you can see around it without focusing directly). 

There is an area of the macula, a small depression called the fovea, which is responsible for detailed vision (visual acuity) and has the highest concentration of colour-sensitive cells in the retina. The information gathered by the cells in the retina is transported by the optic nerve to the brain, which interprets the image that we are seeing. 

Overview of a macular hole 

A macular hole is a rare eye disease. As the name suggests, it is what happens when there is an opening in the macula. The risk of having a macular hole increases with age, with most cases over the age of 60. Other risk factors include trauma to the eye, severe myopia (short-sightedness) and being assigned female at birth. However, they can also be idiopathic, with no known cause. Note the vision loss caused by a macular hole (or other diseases causing vision loss) will not be correctable by wearing glasses or contact lenses.² 

It is a slowly progressing disease, so vision loss will come on gradually rather than all at once. Initially, the fovea detaches from the vitreous humour (the gel-like substance within the eye). This may cause some spots to appear in the central vision, but if the macular hole is only in one eye (and the other eye is working normally), the brain can choose to ignore these spots and focus on the other eye. This will mean that a macular hole in the initial stages can go unnoticed. Around 90% of cases are unilateral, and 10% bilateral (occurring in both eyes) This initial stage can heal on its own, so may not progress to the next stages.

There are four stages of a macular hole, each progressively affecting the vision more severely:²

• Stage 1: Loss of foveal depression
• Stage 2: Full or partial thickness hole of the macula, less than 400 microns in size
• Stage 3: Full-thickness hole of the macula, more than 400 microns in size. Posterior vitreous detachment will have started at this stage
• Stage 4: Full-thickness hole of the macula, more than 400 microns in size, with complete posterior vitreous detachment

Only a small proportion of stage 2 macular holes will spontaneously resolve, with the majority progressing to stage 3. All cases that reach stage 3 will progress to stage 4. Stages 2 through 4 involve progressively greater central vision loss and vision can appear distorted, with straight lines appearing wavy. Vision can also be blurry, with a lack of sharpness for seeing detail. This can cause problems with recognising faces or with reading. Later stages can present with a blind spot in the centre of the vision (can appear like a black spot or floater). 

A Weiss Ring can appear at stage 4 and is a common sign of a posterior vitreal detachment. This is a type of floater, shaped like a dark, thick ring made of collagen that was once on the retina, around the optic nerve, but has now moved forward into the field of vision.² 

Diagnosis 

When diagnosing a macular hole, the patient’s signs and symptoms and past medical history will be taken into account. Medical history is important because conditions such as diabetes and hypertension can affect the retina even if they are not strictly “eye diseases”. Those with a history of retinal detachments are also at a higher risk. For patients over 60, assigned female at birth who have myopia and have some loss or change in central vision, a macular hole is often suspected. While this is the typical presentation, macular holes can actually present at any age and in individuals assigned male or female at birth. 

Diagnostic tests

There are two main investigations used to definitively diagnose a macular hole: 

1. Dilated Pupil Examination: This test involves placing drops in the eye to dilate the pupil, making it larger and allowing a clearer view of the back of the eye, including the macula
2. Optical Coherence Tomography (OCT): This is a scan of the whole eye, giving a three-dimensional image of the retina. The scan can show the presence of a macular hole, and its size and depth. It is the gold standard of diagnostic tests for macular holes, and recent technological advancements in OCT have made it easier to differentiate a macular hole from other similar conditions of the macula such as the epiretinal membrane. OCT scanners can be found at most opticians and eye clinics

The image on the top (source) shows a small section from an OCT scan, with the arrow pointing to the macular hole in the retina.

Though not a diagnostic test, visual acuity can be tested to measure the level of vision loss. This can be done both pre and post-operatively to measure the change, which often involves reading a Snellen chart (the chart with the letters of progressively smaller font sizes).¹

Treatment

Stage 1 treatment

Stage 1 of macular holes typically do not require treatment and are managed through observation. This is because there is spontaneous resolution in around 50% of cases (meaning the hole will close and the fovea will reattach itself), and surgically intervening can cause more harm to the eye. 

Stage 2-4 treatment

For stages 2–4, the primary treatment is a vitrectomy—a surgical procedure performed under local anaesthetic. This procedure involves: 

1. Removing the vitreous gel: It involves inserting small instruments through a small incision in the sclera (the white, outer layer of the eye) to reach the back of the eye. Part of the vitreous humour is removed to relieve traction on the macula
2. Internal Limiting Membrane (ILM) peeling: A critical step in this surgery is peeling the ILM, a thin layer on the surface of the retina. This technique has significantly improved the visual outcomes of macular hole surgery by further reducing macular traction
3. Tamponade: The final step involves using a tamponade to seal the hole and flatten the retina to promote healing. Either a gas bubble or silicone oil is used, and both are effective. The choice of tamponade depends on the specific case. After surgery, patients are usually instructed to lie flat or face down for a period to keep the tamponade in place and avoid its displacement^1,4

Importance of early treatment

Early surgical intervention is crucial for improving outcomes. While surgery is unlikely to restore 100% of the lost vision, the amount of vision regained generally decreases as the stages progress from 2 to 4. The better the vision before the development of the macular hole, the better the prognosis after surgery. Idiopathic macular holes have a more favourable prognosis than those resulting from trauma. Without treatment, macular holes can lead to permanent loss of central vision..⁴ 

Summary

A macular hole occurs when an opening forms in the macula, the part of the retina responsible for the highest visual acuity. Stage 1 macular holes can sometimes resolve spontaneously without treatment. The gold standard for diagnosing a macular hole is Optical Coherence Tomography (OCT), a scan that provides detailed images of the eye. For stages 2 to 4, surgery is the primary treatment approach. This procedure involves relieving the traction between the retina and the vitreous humour, allowing the retina to reattach. Early intervention is crucial for better outcomes, as untreated macular holes can lead to permanent central vision loss.