Introduction

The eye's macula is the round part at the centre of the retina, which is a thin layer at the back of the eyeball. It processes the information in front of your eye and is essential for being able to see. It translates any light that reaches the eye to form images that you see.

The photoreceptors inside the retina react to light, changing it into an electrical signal that travels through the optic nerve and becomes the picture that your brain sees. Cones are specific photoreceptors that process details in vision,  therefore, the macula has a large amount of these. If the eye lacks a macula or has a damaged one, vision would be blurry and undetailed.

A traumatic macular hole is the second most common type of macular hole, with the idiopathic macular hole being the most common. A traumatic macular hole is a full-thickness defect of the retina that is caused by a blunt injury of the eye. While it may lead to permanent vision loss, it is also associated with other retinal disorders, including diffuse retinal oedema, retinal tears and dialysis, choroidal rupture, commotio retinae and retinal haemorrhages.¹

Causes of traumatic macular hole

Traumatic macular holes are more common in the younger male population during their second and third decades of life, because this age group is typically more associated with aspects that may cause ocular trauma, such as recreation, sport, work or transportation.^1,2

Trauma to the eye can result from minor scratches or more severe damage such as lacerations; however, the trauma that causes traumatic macular holes is due to blunt force trauma. The blunt injury to the eye, as mentioned, can include sport-related injuries including ball sports or contact sports, motor vehicle accidents where the face or head can hit parts of the car in a collision, or falls which result in a direct blow to the eye or head.²

Mechanism of the formation of traumatic macular hole

There are two suggested mechanisms for how a traumatic macular hole forms. The first one includes an immediate loss of vision caused by a tear in the fovea, which is a small depression in the centre of the macula responsible for detailed vision.^1,3 The other mechanism leads to a delayed loss of vision caused by a tear from the abnormal sticking of vitreous gel, being a substance that fills the space between the lens and retina, and the fovea.¹

Symptoms and signs of traumatic macular hole

In the earlier stages, a macular hole may cause distorted or blurred vision, where you may have trouble reading fine print and a straight line appears wavy or curly. As the hole progresses and develops, you may see a black or “missing” patch in your vision causing a blind spot. These will occur in the centre of your vision as this is where the macula is. These symptoms only arise in the eye with the macular hole.

Diagnosis of traumatic macular hole

The diagnosis of a traumatic macular hole begins with the healthcare professional understanding your family and medical background, including any medications that you take. An eye exam is then completed which includes a slit lamp exam. Eye drops are placed into your eyes to dilate pupils for retina examination. 

On clinical examination, a round defect of the retina in the macula is apparent with a surrounding of subretinal fluid. There may also be evidence of retinal oedema or subretinal haemorrhages if this examination is done immediately after the trauma. Traumatic macular holes typically involve the foveal centre but can extend further; this is particularly common if they have arisen from surgical trauma. Various specific tests can be performed to confirm the diagnosis.⁴

Optical coherence tomography (OCT) is a non-invasive imaging method, which generates a high-resolution picture of the retina. It measures the amount of red light that reflects off of the retina and optic nerve and then, it can measure the thickness, and size of the retina.

A fluorescein angiography is when a specialist administers eye drops to dilate your pupils, and then injects a dye, known as a fluorescein, into a vein in the arm. This dye travels to the blood vessels in the eye and highlights them, so the specialist can screen for conditions that affect vision.

Fundus photography is when a fundus camera captures images of the retina. These images are analysed by a specialist to diagnose ocular diseases, such as a macular hole. The retina is illuminated and reflects through the pupil to form these images.⁵

Treatment of traumatic macular hole

There have been some reports of traumatic macular holes that spontaneously close without treatment. These happened between two weeks and 12 months after the trauma. Holes can either reduce in size or close completely, and there is significant visual improvement afterwards. It is known that spontaneous closure is more common in young patients with smaller holes, resulting from less severe eye injuries. Spontaneous closure occurs through the mechanism involving the growth of glial cells, or retinal pigment epithelial cells, from the edges of the hole to cover and fill the hole. Alternatively, astrocytes may move to the hole to heal it. Due to the chance of spontaneous closure, specialists may suggest an observation period of 3 to 6 months, especially in younger patients or those with small holes.¹

A surgical keyhole procedure called a vitrectomy may be used where the vitreous gel of the retina is removed. The specialist surgeon may also remove any parts of tissue that are creating tension on the macula. After the surgery, a sterile gas is administered into the eye to maintain pressure on the hole until it heals. An observation period is often recommended first because a vitrectomy comes with complications. These may include retinal detachment, bleeding, glaucoma, infections or the macular hole never closing after the surgery. 

These complications can potentially lead to blindness if not treated but can be prevented if the post-surgery procedures are followed correctly. If the surgery does not close the hole, your vision will typically still be stable and have less distortion. In rare cases of the hole not closing after surgery, central vision can deteriorate further. In these instances, a second operation may be carried out to close the hole successfully.

Prognosis of a traumatic macular hole

A vitrectomy has a success rate of over 90% and is more successful with a smaller hole that has formed more recently. After the procedure, you should avoid driving and flying so that your body can absorb the sterile gas without significant changes in air pressure. This can cause the air bubble to expand and cause high pressure, leading to severe pain and potentially permanent loss of vision. Without any treatment, your central vision may be lost however peripheral vision will be retained.

FAQs

How quickly do traumatic macular holes form?

Conversely, to idiopathic macular holes which form slowly over months, traumatic macular holes usually form immediately after the eye experiences trauma but can develop in the weeks following injury.⁴

What else can cause macular holes?

Another cause may be associated with age, and vitreomacular traction, which is where the vitreous gel in the eye pulls away from the macula as you age, and remains attached to the retina as it shrinks, potentially pulling a part of the retina away forming a macular hole. Other causes involve retinal detachment from blood vessels that supply the retina with oxygen, being long or short-sighted and swelling of the central retina.

How can a macular hole be prevented?

While participating in contact or ball sports, protective wear, such as eye coverings, should be worn. Despite not directly preventing a macular hole, having regular eye examinations can ensure that a macular hole is found earlier and therefore treated earlier.

Summary

A traumatic macular hole is a full-thickness defect in the retina and can arise from a blunt injury to the eye, causing a blind spot in central vision. It can cause blurry or distorted vision, which is repaired through spontaneous closure, or a vitrectomy, typically after an observation period. If you experience the symptoms of a macular hole or have had any trauma to the eye, you should consult a healthcare specialist to prevent the macular hole from enlarging.