Injuries involving the eye and adjacent structures
Corneal
abrasions and ulceration
The cornea is frequently damaged by trauma and
foreign bodies (Fig. 36.16). Ulceration can occur with infection or after damage
to the facial nerve (Chapter 34). Post herpetic ulceration is common and serious
if not treated. Fluorescein instillation can show up cornea) ulceration at an
early stage. Treatment is by protection (eye pads, tarsorrhaphy or a bandage
contact lens), and antibiotics topically and systemically: 0.5 per cent
chloramphenicol or ofloxacin eye drops are commonly used. The eye is made more
comfortable by the use of mydriatics such as homatropine or cyclopentolate.
Herpes simplex ulcers are treated with acyclovir ointment. In countries in the
Far and Middle East chronic infection with trachoma can cause corneal
opacification and blindness. Cornea) grafting is the only cure for an opaque
cornea. Osteo—odonto keratoprosthesis can be done in very severe cases of
opaque corneas which are not suitable for grafting. Acanthoemeba is a serious
cause of cornea) infection. This fungal corneal infection usually follows the
use of contact lenses. These rare cases need specialist treatment.
Blunt injuries
to the eye and orbit
The floor of the orbit is its weakest wall,
and in blunt trauma, such as fist injuries, it is often fractured without
fractures of the other walls. This is called a blow-out fracture. Clinical signs
are enophthalmos, bruising around the orbit and limitation of upward gaze and
diplopia. This occurs when the extraocular muscles become trapped in the
fracture, and can be identified as a soft tissue mass in the antrum on a
radiograph (Fig. 36.17), although tomograms or CT scans may be necessary. Surgical repair
of the orbital floor with freeing of the trapped contents may be necessary if
troublesome diplopia persists. Large doses of steroids sometimes relieve
symptoms in acute cases. If an orbital haemorrhage is too extensive to examine
the eye, it may be necessary to examine
Blunt
injuries can also cause damage to the optic nerve which can result in blindness
and a total afferent nerve defect (Fig 36.18 and Fig
36.19).
Concussional
injuries
Concussional injuries of the eye can give rise
to several problems, which include the following.
• Hyphaema (blood in the anterior chamber) (Fig. 36.20). Bed rest and sedation are
advised because the main danger in this condition is secondary bleeding,
resulting in an acute rise in intraocular pressure and blood staining of the
cornea. The use of antifibrinolytic agents (e-aminocaproic acid) has been
advocated and, if the pressure rises, surgery to wash out the blood may be
necessary.
• Subluxation of the lens can be suspected if the iris, or part of the
iris, ‘wobbles’ on movement .
• Secondary glaucoma often associated with recession of the angle.
• Retinal and macular haemorrhages and choroidal tears (Fig.
36.21).
• Retinal dialysis, which may lead to a retinal detachment and permanent
damage to vision (Fig. 36.22).
Penetrating eye
injuries
These occur when the globe is penetrated,
often in road traffic and other major accidents (Fig.
36.23), and also in
injuries from sharp instruments. In the UK, the seat belt law has reduced this
type of eye injury by up to 73 per cent in
Intraocular
foreign bodies
Intraocular
foreign bodies must always be excluded when patients attend the accident and emergency
department with a history of working with a hammer and chisel. Radiography
of the orbits should always be performed, and ferrous and copper foreign bodies
should always be removed. Beta-scan ultrasonography can also assist in
localising foreign bodies when a vitreous haemorrhage is present. CT can be
used, but MRI is contraindicated for orbital lesions.
Burns
Radiation burns
These occur after exposure to ultraviolet
radiation after arc welding or excessive sunlight (snow blindness) and sun
lamps. Such burns cause intense pain and photophobia due to a keratitis, which
may start some hours after exposure. Mydriatic and local steroid drops ease the
condition, and healing usually occurs after 24 hours.
Thermal burns
If these involve the full thickness of the
lids, corneal scarring may occur, and immediate skin grafting to the lids is
necessary. A splash of molten metal may cause marked local necrosis, and may
lead to permanent corneal scarring. Treatment is to remove any debris by
irrigation, and to instil local atropine, antibiotics and steroids to prevent
superadded infection and scarring.
Chemical burns
Chemical burns, and especially alkali burns,
can be serious because ocular penetration occurs quickly and ischaemic necrosis
can result. Immediate irrigation will ensure that the chemical is diluted as
much as possible, and all particles should be removed from the fornices.
Treatment can then be continued as with thermal burns. Well-fitting goggles
should prevent such injuries (Fig. 36.24).