Etiology: Together with severe chemical injuries, open-globe injuries are the most devastating forms of ocular trauma. They are caused by sharp objects that penetrate the cornea and sclera. A distinction is made between penetration with and without an intraocular foreign body. However, even blunt trauma can cause an open-globe injury in an eye weakened by previous surgery or injury where extremely high-energy forces are involved (such as falling on a cane or a blow from a cow's horn).
Clinical picture and diagnostic considerations: Penetrating injuries cover the entire spectrum of clinical syndromes. Symptoms can range from massive penetration of the cornea and sclera (Fig. 18.7) with loss of the anterior chamber to tiny, nearly invisible injuries that close spontaneously. The latter may include a fine penetrating wound or the entry wound of a foreign body. Depending on the severity of the injury, the patient's visual acuity may be severely compromised or not influenced at all.
One of the most common sequelae is a traumatic cataract. The rupture in the lens capsule allows aqueous humor to penetrate, causing the lens to swell. This results in lens opacification of varying severity. Large defects will lead to total opacification of the lens within hours or a few days. Smaller defects that close spontaneously often cause a circumscribed opacity. Typically, penetration results in a rosette-shaped anterior or posterior subcapsular opacity.
Depending on the severity of the injury, the following diagnostic signs will be present in an open-globe injury:
❖ The anterior chamber will be shallow or absent.
❖ The pupil will be displaced toward the penetration site.
— Penetrating injury.
— Penetrating injury.
❖ Swelling of the lens will be present (traumatic cataract).
❖ There will be bleeding in the anterior chamber and vitreous body.
❖ Hypotonia of the globe will be present.
The rupture of the lens capsule and vitreous hemorrhage often render examination difficult as they prevent direct inspection. These cases, and any patient whose history suggests an intraocular foreign body, require one or both of the following diagnostic imaging studies:
❖ Radiographs in two planes to determine whether there is a foreign body in the eye.
❖ CT studies, that permit precise localization of the foreign body and can also image radiolucent foreign bodies such as plexiglas.
H An injury sustained while working with a hammer and chisel suggests an intraocular foreign body. The diagnosis may be confirmed by examining the fundus in mydriasis and obtaining radiographic studies.
Treatment: First aid. Where penetrating trauma is suspected, a sterile bandage should be applied and the patient referred to an eye clinic for treatment. Tetanus immunization or prophylaxis and prophylactic antibiotic treatment are indicated as a matter of course.
Surgery. Surgical treatment of penetrating injuries must include suturing the globe and reconstructing the anterior chamber. Any extruded intraocular tissue (such as the iris) must be removed. Intraocular foreign bodies (Figs. 18.8a and b) should be removed when the wound is repaired (i.e., by vit-rectomy and extraction of the foreign body).
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