Anterior Segment Damage In Contusion Eye Injury

Damage to the anterior segment may result in corneal abrasions, hyphaema and associated damage to the ciliary body, iris or lens. Secondary complications, such as recurrent bleeding, uveitis and abnormal intra-ocular pressure may also occur.

Subconjunctival hemorrhages

The conjunctiva, being the most superficial layer, often displays subconjunctival hemorrhages, but these reabsorb within several weeks and do not need treatment. However, subconjunctival hemorrhages caused by orbital bleeding can be so severe that the conjunctiva projects between the lids and requires prompt attention.

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Hyphaema

The anterior chamber may appear red as the result of the presence of blood. This is known as hypaema and is due to the rupture of a vessel in the iris or ciliary body. The chamber is generally only partially filled and the blood settles inferiorly. It will usually be reabsorbed without any serious consequences. However, in some cases, the anterior chamber may completely fill with blood (total hyphaema).

If the blood is not reabsorbed after a few days, it's color changes from red to purple to black. This occurs due to a lack of oxygen from the aqueous and is sometimes referred to as an 'eight ball' hyphaema. This is a serious condition, as the intra-ocular pressure is generally elevated, resulting in secondary glaucoma and possible blood staining of the cornea.

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Re-bleeding may occur, resulting in secondary glaucoma, blood staining of the cornea and permanent loss of vision. The source is uncertain but it may arise from newly formed capillaries in the area of damage, or from the original leaking blood vessel. It usually occurs in the first five days after injury. Surgery is frequently required in cases of re-bleeding and it should therefore be prevented if at all possible. Given the possible complications, hyphaemas must always be referred, however small the amount of blood visible in the anterior chamber.

Recommended: Posterior Segment Damage In Contusion Eye Injury

The individual may be admitted to hospital and bed rest given for a couple of days. Hyphaemas may also indicate the presence of scleral ruptures. The most common sites are in a circumferential arc parallel to the corneal limbus, opposite to the impact site at either the insertion of rectus muscles on the globe or at the equator of the globe. This type of injury commonly occurs after a squash ball has hit the eye.

Iris

Damage to the iris may result in dilation or constriction of the pupil; this is known as traumatic mydriasis or traumatic miosis, respectively. Depending on the severity of the blow, the paralysis may be temporary, last only a few days or permanent.

Ruptures may occur to the sphincter pupillae, leaving a permanently irregular, semi-dilated pupil, which will not react to light or accommodation. The iris can be torn from its insertion to the ciliary body; this is known as iridodialysis. It is a permanent condition, usually accompanied by hyphaema and results in a distortion of the pupil. Both conditions will cause symptoms of glare, especially in the case of iridodialysis where a second pupil has formed.

Angle recession

Traumatic angle recession of the anterior chamber can lead to the development of unilateral glaucoma months or years later. It is caused when the ciliary body has been torn from the sclera. Extensive angles of recession have been found in subjects with prolonged primary hyphaemas. The site of the recession can be predicted from the presence of traumatic mydriasis. The affected area of the pupil is atonic, neither fully dilates nor constricts and corresponds to the position of the angle recession.

Lens

The zonular fibres that attach the lens to the ciliary body can be torn in a contusion injury. As a result, the lens may have become totally dislocated from its attachment or partially dislocated (subluxated). The dislocated lens may fall either posteriorly into the vitreous, where low-grade ophthalmitis may occur or enter the anterior chamber, causing corneal endothelial damage. There will be a marked hyperopia shift in the refraction and a tremulous iris (iridodonesis) may be seen due to the loss of support by the lens.

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A subluxated lens produces a prismatic effect upon vision, with the upward displacement of objects. This may cause symptoms such as diplopia, nausea and vomiting. The sudden compression and expansion of the lens, with or without rupture of the capsule, can produce a cataract. In fact trauma is the most common cause of unilateral cataract in the young. Various types of lens changes which can occur includes: vossius ring opacity, sub-epithelial disseminated opacities, traumatic rosette-shaped cataract, diffuse cataract and zonular cataract.