What Is Open Globe Injury?

Introduction

The medical term ‘globe injury’ refers to an injury to the eyeball. An open globe injury occurs when this injury causes a hole that extends through the full thickness of the wall of the eye, often allowing the contents of the eyeball to leak.¹ It is different from superficial injuries such as a corneal abrasion, where a small scratch occurs on the exterior of the eyeball. Open globe injuries can be extremely serious and can lead to a permanent loss of vision in the affected eye.

Anatomy of the eye

The wall of the eye  consists of three layers:² 

• The fibrous tunic,
• The vascular tunic, and
• The retina

The fibrous tunic is the layer found on the outside of the eye and contains two structures, the sclera and the cornea. 

The sclera is also known as the white of the eye and helps keep the spherical shape of the eye intact. 

The cornea is the clear portion, covering the iris and the pupil. 

The limbus is the border between the iris and the sclera.² 

The middle layer of the eye wall is the vascular tunic, also known as the uvea. The vascular tunic it self is comprised of three parts, the choroid, the ciliary body, and the iris. The choroid body is rich in blood vessels supplying the retina. 

The ciliary body contains muscular fibres which contract and relax to change the shape of the lens and adjust focus for near- or far-sightedness. The ciliary body also produces the aqueous humour, a clear liquid involved in regulating the pressure of the eye. 

The iris is the coloured part of the eye, responsible for regulating the size of the pupil (a hole in the centre of the iris) and the amount of light entering the eye.² 

Between the lens and the retina, is a space called the vitreous cavity which is filled with vitreous humour, a clear, gel-like fluid that helps to maintain the shape of the eye.

Lastly, the innermost layer of the eye is the retina. 

Light passes through the fibrous tunic and the vascular tunic to reach photoreceptors found within the retina, termed rods and cones.³ This light is processed into electrical signals, which are transmitted to the brain along the optic nerve.

An injury can penetrate either the cornea, the sclera, or both. The eye is filled with vitreous and aqueous fluid, rendering it highly pressurised. When trauma occurs to the eyeball, this pressure increases and can cause a rupture to the wall itself, often in an area where the sclera is thinnest.

Causes of open globe injuries

Open globe injuries occur when an object forcefully strikes the eye, either directly cutting through the eyeball wall or causing a sudden increase in pressure that leads to a rupture. These injuries are often associated with falls, especially among individuals aged 75 and older.

Such injuries can be classified into two main types: blunt trauma events and penetrating trauma. Blunt trauma often occurs during sports-related activities or altercations. Penetrating trauma, on the other hand, typically results from incidents involving motor vehicles or industrial machinery failures, leading to airborne debris. Additionally, penetrating trauma can be caused by sharp objects such as knives, fishing hooks, scissors, and explosions like fireworks.

Signs and symptoms

Following an injury to the eyeball, there may be immediate visual disturbances, such as loss of vision or blurred vision. There may be extreme sensitivity to light, rendering the patient unable to open their eye. The individual will also experience pain and discomfort within the eye, which may lead to vomiting.

Other external signs of injury include

• Leakage of blood, aqueous humour, vitreous humour, or tissue from the eyeball.
• The pupil may become irregular in shape, termed iris prolapse, or it may be unreactive to light.
• Iridodialysis, tears in the tissue of the iris, lead to black regions on the outer edge of the iris and a loss of the regular spherical shape. These black regions are chambers filled with blood, an occurrence termed hyphema.
• A deflated eyeball, where leakage of fluid has resulted in a loss of pressure within the eye.
• If the injury has also penetrated the eyelid, bleeding and cuts to the surrounding tissues may also be seen.

Diagnostic procedures

Ophthalmic examination

A physical examination and medical history are the first diagnostic methods utilised if an open globe injury is suspected. A clinician will use a slit lamp eye exam to check for wounds. The clinician will utilise a microscope attached to a bright light, and adjust the brightness and focus to assess different regions of the eyeball. 

A clinician may also use a Seidel test to check for open globe injuries. In this instance, the eye is washed with a topical anaesthetic, the flushed with a fluorescent dye. This dye appears green under certain light, but in the case of an open globe injury, aqueous fluid leaking from the eye will turn the dye green.¹

The clinician may also use the Snellen eye test to check for vision loss. This is a common test, often used in regular eye exams, where the patient is asked to identify letters which become increasingly smaller in size.

Imaging techniques

A computed tomography scan (CT scan) is a type of x-ray. A classical x-ray will show damage to the eye socket, but cannot be used to diagnose open globe injury and is unable to detect the penetrating foreign body.⁴ The superior CT scan is the recommended imaging technique in cases of open globe injury.

They may show changes in the shape of the eyeball, vitreous haemorrhage, or eyelid swelling, and they are quick to perform.^5,6 A CT scan can also be used to diagnose injury to surrounding structures, such as a fracture to the bone of the eye socket.

A magnetic resonance imaging (MRI) scan is a useful diagnostic tool, as it can provide useful imaging and allow the doctor to differentiate a haemorrhage within the eye from oedema (swelling). However, it is not often used as the first diagnostic tool, in case of metal fragments remaining in the eye following the trauma. An MRI also takes much longer to perform, which may result in worse outcomes in the case of open globe injuries.

Classification of open globe injuries

There are different types of open globe injuries, classified by the type of wound and the status of the penetrating object.

• Globe rupture is an injury to the eyeball caused by blunt trauma increasing the internal pressure of the eye, causing a rupture of the wall.
• Full-thickness globe laceration is an injury to the eyeball caused by a sharp object cutting from the outside of the eye. Lacerations can also be divided by their penetrating or perforating status.
• Globe penetration is an injury to the eyeball, where the penetrating object remains within the eye.
• Globe perforation is an injury to the eyeball, where the penetrating object no longer remains within the eye.

Open-globe injuries are also graded by their severity and can be classified by:⁷

• The effect of the injury on vision,
• the presence/absence of a defect in pupillary function (e.g. change in shape, or lack of reactivity to light), and
• the areas of the eye wall breached. 

The injury will be denoted as zone I, II, or III, depending on the deepest part of the wound:

• Zone I: cornea and limbus.
• Zone II: An area beginning at the edge of the limbus and extending outwardly by 5 mm.
• Zone III: Any of the eye wall extending beyond the cornea, limbus, and 5mm ring of Zone II. 

The Ocular Trauma Score is used to predict the long-term outcome of an open globe injury on the patient’s vision, ranging from 1, where the injury is extremely serious with a poor prognosis, to 5 where the injury is the least serious and the patient has the best prognosis.⁸

Treatment approaches

Emergency measures

It is important not to touch the eye of a person with an open globe Injury, as adding pressure or aggravating the wound may make the injury worse. 

Immediately after the injury has occurred

• Keep the eye protected,
• avoid any strain that may cause pressure to the eyeball, like lifting,
• take medication to ease the pain and prevent vomiting, as this can increase the pressure within the eye, and
• seek medical attention. 

The sooner the injury can be diagnosed and treated, the greater the chance of retaining vision.

Surgical interventions

Often, open globe injuries require surgery, normally within 24-48 hours of the injury occurring. Surgeons will explore and flush the wound using a surgical microscope and saline, respectively, to remove any debris whilst the patient is under general anaesthetic. They will then use sutures (or stitches) to close the wound and allow the tissue of the eye to heal. If part of the inside of the eye has started to protrude out of the wound, the surgeon will repair or remove this during the operation. Often an initial surgery is performed to close the wound and restore the pressure within the eyeball, however, secondary surgeries may be required to improve vision. 

After the surgery, the patient will be required to wear a protective covering whilst the eye is healing to prevent additional injury.

Complications and prognosis

Infection

As the sealed wall of the eye has been breached, and the eyeball is no longer sterile, there is a risk of infection following open globe injury. Antibiotics will be prescribed by the doctor, to prevent infections of the wound.⁹ In certain cases where soil has penetrated the wound, anti-fungal medications may also be prescribed. Additionally, patients may require a tetanus vaccination if the injury was caused by metal.

Long-term visual implications

The surgery performed will often only close the wound, and there may be long-term complications following the injury. If the penetrating object damages the retina or the iris, this may cause visual impairments or complete loss of sight in the affected eye.¹

Severe complications may include:

• Blindness
• Retinal detachment¹⁰
• Choroidal rupture
• Phthisis bulbi
• Endophthalmitis (infection of the eyeball)¹¹
• Loss of the eye
• Orbital compartment syndrome
• Sympathetic ophthalmia¹²
• Development of cataracts
• Glaucoma

Rehabilitation and follow-up care

After the initial treatment to heal the wound, follow-up appointments will be scheduled to check the healing progress, as well as assess eyesight. A person who has suffered an open globe injury may still encounter the following long-term effects, such as pain in the eye, even after the wound has healed.

Prevention strategies

Many open globe injuries can be prevented, due to the use of protective equipment and the instillation of safety measures in high-risk environments. For example, in situations where mechanical equipment may cause injury, wear protective eyewear and follow instructions carefully when using machinery. Protective eyewear should also be worn during contact sports where there is a risk of injury. Sharp objects in the home should be kept out of reach of children.

Conclusion

Open globe injuries occur when a wound to the eye penetrates the full thickness of the wall of the eye. They can be extremely serious, causing disturbances to or loss of vision, and often require surgery to remove the foreign object that caused the injury and to heal the wound. It is imperative to treat an open globe injury on time, to minimise and restore pressure within the eyeball as quickly as possible. The more swiftly an open globe injury is treated, the better the prognosis for maintaining vision.