A number of ophthalmological conditions presenting in general practice have the potential to cause loss of sight and should therefore be considered emergencies. It is important to be able to identify these conditions so that urgent or immediate referral can be made to an ophthalmologist.
The patient should be asked about the onset and progression of the symptoms; whether there are any visual changes such as flashers, floaters, blurring or loss of vision and the presence of pain, discharge or photophobia.
History and examination
It is important to enquire about any previous eye disease or surgery and whether contact lenses are used. A previous history of co-morbid conditions, such as collagen vascular disease, and any family history of glaucoma should be noted.
An eye examination should then be carried out. It may include a test of visual acuity, with spectacles if they are used, an examination of eye movements and the bony orbit, particularly in cases of trauma, a check of visual fields and an examination of the lids and lashes to check for scaling, redness or oedema.
In addition, the cornea should be examined for signs of oedema, ulcers, opacification and foreign bodies, and the anterior chamber for clouding, pus and blood. Intraocular pressure should be tested by palpation in suspected glaucoma.
The size, shape and reactivity of the pupil should be noted and the patient should be tested for direct and consensual photophobia (pain in the affected eye when light is shone in the unaffected eye).
Blunt trauma such as a punch can cause a ‘blow-out’ fracture of the floor of the orbit. This will result in diplopia, inability to move the eye superiorly and, less commonly ptosis, anaesthesia of the infraorbital nerve and enophthalmos.
A more rare complication is retrobulbar haemorrhage, which can cause pain, diplopia, visual field defects and proptosis. Both conditions require urgent surgical intervention.
Penetrating eye injury is sometimes immediately apparent, as in the case of a fishhook embedded in the eye. A penetrating injury should also be suspected in eyelid lacerations, particularly if there is bleeding coming from under the eyelid.
In these cases further examination should not be made as it may worsen the injury. Immediate referral is needed and the eye should be protected during the journey to hospital. This can be done with a shield or plastic cup.
High-velocity penetrating injuries may not be immediately apparent so the patient should be asked about the activity preceding the injury. Hammering on metal, using high-speed tools such as drills, lathes and grinders, wire cutting and use of high-pressure water, air or oil are all high-risk activities.
Signs may be present such as an abnormal red reflex, uneven pupil or a visible foreign body in the eye but, even if absent, it is better to refer for a more detailed examination.
Painful red eye
Simple bacterial or viral conjunctivitis presents with a red eye together with mild discomfort or itching.
However, further investigation will need to be taken if the patient reports severe pain as this is associated with more serious disease.
A herpes zoster ophthalmicus infection may be obvious from the characteristic rash on the forehead, but up to half of patients have corneal involvement and/or uveitis.
Corneal ulcers are common in contact lens wearers and present as a white opaque area. A discharge, or occasionally hypopyon, may be present.
Dendritic ulcers are caused by herpes simplex. It is important not to use steroid drops as these cause exacerbation.
Iritis and anterior uveitis present with a unilateral intensely painful red eye.
There is often consensual photophobia. Keratin precipitates may be seen on the back of the cornea and the pupil is generally constricted.
Patients suffering from these conditions should be referred for evaluation and steroid treatment. Acute angle-closure glaucoma presents as a unilateral, intensely painful red eye in patients aged over 55 years.
The cornea is cloudy and the pupil oval and mid-sized. Palpation of the eye can confirm the raised pressure.
Immediate referral is needed. If a delay is anticipated, the pupil can be constricted using pilocarpine or timoptol. The patient may also require strong analgesia.
Flashers and floaters
Long-standing floaters and visual flashers are unlikely to be significant.
The most common cause of flashers and floaters is posterior vitreous detachment, which affects three quarters of patients aged over 65 years.
Symptoms usually fade with time but in a small number of cases retinal holes may develop. If these are detected early, laser treatment can prevent progression to retinal detachment. The visual loss in retinal detachment may not be symptomatic until the detachment crosses the macula. The patient then presents with sudden partial or total loss of vision in one eye. Examination may reveal a partial loss of red reflex and the peeled-back retina. Surgery is required.
A sudden increase in floaters may be a sign of vitreous haemorrhage. It is more common in diabetic patients and if severe it may obscure vision.
A patient with sudden loss of vision should always be considered an ophthalmological emergency, once the possibility of stroke has been eliminated. Sudden vision loss may be caused by ischaemic optic neuropathy, which is associated with temporal arteritis and amaurosis fugax.
It can also be a sign of branch and central retinal artery occlusion, macular haemorrhage and optic neuritis.
Dr Spinks is a GP in Strood, Kent
- Excessive examination of penetrating eye trauma should be avoided as this can worsen the condition.
- High-speed penetrating injuries may not be immediately apparent. If there is cause for suspicion it is best to refer for a more detailed examination.
- Painful red eyes should raise suspicion, particularly in older patients or if unilateral, as they can be a sign of serious disease.
- Although floaters and flashers are very common, recent onset floaters or flashers can indicate vitreous haemorrhage, especially in diabetic patients.
- Sudden visual loss should be treated as an emergency.
- Retinal Detachment
- Red Eye Evaluation