GENERAL METHOD FOR AN INJURED EYE

For burns of the eye, see Section 58.28. For the basic methods, see Section 23.1.

REFERRAL If you decide to refer a patient with an eye injury, instil antibiotic drops into his eye, fit his eye with a protective shield (23-1), and refer him lying down. If the journey is long, or is likely to be delayed, give him oral chloramphenicol 500 mg initially, followed by 250 mg 6 hourly for 5 days. HISTORY Take as careful a history as you can.

LOCAL ANAESTHESIA FOR EXAMINATION Pain will make a patient keep his injured eye shut. Local anaesthesia will make it easier to examine. Retract his lower lid and instil 2 drops of local anaesthetic. This can be 2% or 4% Iignocaine, or decicaine 1%, or tetracaine hydrochloride 1%, or proparacame hydrochloride 0.5%, or cocaine 4% to 10%. You may have to make many instillations before anaesthesia is effective—see A 5.8.

CAUTION! (1) Don’t put ointments ito a patient’s eye, they will make it difficult to examine later. (2) Topical anaesthetics, dyes, and drugs must be sterile. They can readily become infected, especially with Ps. pyocyaneus. Tetracaine and fluorescein can be autoclaved repeatedly. (3) Don’t give a patient a local anaesthetic to take home—he may injure his anaesthetic cornea, and the drug may delay healing.

THE EXAMINATION OF AN INJURED EYE

Start by examining the visual acuity of both the patient’s eyes, his normal one first. Lie him down, examine him in a good light and use whatever means of magnification you have.

If he cannot open his eye himself, gently open his lower lid by pulling down the skin over his zygomatic arch. Instil local anaesthetic. This will probably relieve his pain enough to let him open it himself.

If he is still unable to open his eye, put a Desmarre’s retractor gently under his upper lid, and lift it upwards away from the globe. Or, use a retractor made from two bent and sterilized paper clips.

If even this fails, you may have to wait until you anaesthetize him before operating.

CAUTION! Avoid pressure, either by squeezing his eye, or by letting him squeeze his eye with his lid. If his globe is perforated, pressure may squeeze the contents out of it.

SIGNS OF INJURY IN THE EYE

Examine the patient’s lids carefully. A tiny laceration may be the opening of a track which penetrates his globe, as in Fig. 60-9. Examine his conjunctiva for haemorrhage, foreign bodies, or tears. Note the depth and clarity of his anterior chamber. Compare the size, shape, and light reaction of his pupils.

If his globe is intact, examine the fornices of his conjunctiva and evert his upper lid, as in Fig. 23-2. Dilate his pupils and examine his fundus with an ophthalmoscope.

Examine his lens, his vitreous, and his retina for signs of haemorrhage, or retinal detatchment.

Examine his cornea and his sclera for wounds and abrasions. Put drops of fluorescein into his conjunctiva. Don’t try to feel the tension in his globe, because if you do, you may squeeze out its contents. You will however get some idea of its tension as you examine it.

If there is blood under a patient’s conjunctiva, be careful: (1) Even a very small bruise may mark the site where a small foreign body has entered his sclera, as in Fig. 60-9.(2) Haemorrhage at the limbus is itself unimportant. It is only likely to be serious if it extends far posteriorly, when it may indicate a fracture of the base of his skull (62.1).

If his anterior chamber is shallow, he has a penetrating injury of his cornea, which has allowed his aqueous to leak.

If his iris trembles when his eye moves, his lens may have dislocated.

If there is a greyish area in his cornea with swollen margins, his cornea has perforated. In severe cases he may have no anterior chamber, so that his iris touches his cornea.

If a black mass of tissue bulges through the lips of a wound, as in B, Fig. 60-7, his iris or his choroid has prolapsed. If the wound is in his cornea, his pupil will be irregular and drawn towards it as in J, Fig. 60-6.

If his eye feels soft, his globe has probably ruptured. The rupture is nearly always curved, parallel to the limbus, and about 5 mm behind it. Feel the bony borders of his orbit. X–ray his skull and his orbit.

If you can see the edge of his lens with an ophthalmoscope, and he has some visual impairment, the suspensory ligament of his lens is partly ruptured. If it is also tipped the pressure in his eye may rise. If this happens, give him acetazolamide and refer him.

If his lens is completely dislocated, you may see it lying in his anterior chamber, or at the bottom of his vitreous. He will also have a severe visual impairment. There may be no immediate reaction. But an inflammatory response and a secondary rise in pressure are common. Give him acetazolamide and refer him. His lens may need removing.

If he has severe proptosis, goto Section 62.1. He has a retrobulbar haematoma.

If his eye is hopelessly injured, don’t consider enucleating it, unless he is unaware of any sensation of light whatever, when you shine a strong li ght into it. This light must be strong, because it may have to shine through the clot in his eye. If he has any perception of even a strong light, a suprising amount of vision may have returned 6 months later.

ANAESTHESIA Remember that the patient’s stomach may be full. Any rise in the pressure in his globe maymake the injury worse. You can use ketamine. If his eyes move about, give him a little more. Be sure to premedicate him.

Don’t use a retrobulbar block, because if it happens to bleed and his globe is ruptured, the clot may force the contents of his eye out of the wound.

THE FURTHER MANAGEMENT OF AN INJURED EYE

Read on for ’black eye’ (60.2), injuries of a patient’s eyelids canaliculae and conjunctiva (60.3), injuries of his cornea and sclera (60.4), injuries of his iris (60.5), penetrating injuries (60.6), blunt injuries of his globe (60.7), bleeding into an injured eye (60.8), foreign bodies (60.9), and endophthalmitis (60.10).

YOU MUST HAVE A BRIGHT LIGHT AND GOOD MAGNIFICATION