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The eye in general medicine 

The eye in general medicine

Chapter:
The eye in general medicine
Author(s):

Peggy Frith

DOI:
10.1093/med/9780199204854.003.02501
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date: 30 March 2017

All physicians should be aware of important eye symptoms, learn how to examine the eye, and in particular be proficient with the ophthalmoscope. Common presentations include (1) red eye—may be due to conjunctivitis, episcleritis, scleritis, iritis, keratitis, or acute glaucoma, some of which require urgent specialist opinion; (2) dry eye—which may have a systemic cause, particularly if accompanied by dryness of the mouth (sicca syndrome), e.g. Sjögren’s syndrome; (3) loss of vision—which, when it affects one eye, is associated with a relative afferent pupillary defect and can be caused by central retinal artery occlusion, ischaemic central retinal vein occlusion, ischaemic optic neuropathy, optic neuritis, extensive retinal detachment, advanced unilateral glaucoma, and optic nerve compression.

Visual loss—the predominant causes vary according to country: conditions such as glaucoma and macular degeneration predominate in affluent populations, whereas infections and dietary deficiencies (vitamin A) cause blindness in the poor.

Diabetes mellitus—retinopathy is the most common serious eye complication and the commonest reason for blind registration of younger adults in industrialized populations. It can be classified as (1) background—microaneurysms, dot/blot haemorrhages, and hard exudates; (2) maculopathy—where hard exudates within one optic disc diameter of the fovea threaten vision; (3) ischaemic and preproliferative—with changes including multiple blot haemorrhages, dilatation, beading, looping, or tortuosity of the larger retinal veins, or multiple cotton wool spots; (4) proliferative—with tufts of new vessels on the optic nerve head itself or in the peripheral retina. Screening for retinopathy is imperative as laser treatment arrests progression of maculopathy and controls neovascularization.

Hypertension—long-standing high blood pressure and ageing produce similar changes; arterioles are narrowed, irregular or tortuous, and the wall may be thickened (sclerosis), showing an increase in reflected light described as ‘copper’ or ‘silver’ wiring. There may appear to be ‘nipping’ in at arteriovenous crossings where the underlying vein appears to be constricted. Most important is to identify the patient with changes of accelerated hypertension—haemorrhages, cotton wool spots, and papilloedema—which requires urgent management (see Chapter 16.17.5).

Ocular vascular occlusion—includes (1) retinal vascular occlusion—caused by embolic occlusion of the retinal artery or in situ retinal vein occlusion, this is a common cause of unilateral blindness, especially in older patients; (2) occlusion of vessels supplying the optic nerve—giant cell arteritis causes occlusion of ciliary branches of the ophthalmic artery, with acute ischaemia of the optic nerve and irretrievable visual loss, preventable with high-dose corticosteroid.

Systemic inflammatory disorders—many of these may affect the eye, including (1) sarcoidosis—may cause conjunctival granulomas, uveitis or optic neuropathy; (2) Behçet’s syndrome—characterized by potentially blinding panuveitis and occlusive retinal vasculitis; (3) giant cell arteritis; (4) rheumatoid arthritis—causes keratoconjunctivitis sicca and sometimes ischaemic necrotizing scleritis; (5) ankylosing spondylitis—a common cause of iritis in younger people; (6) Reiter’s syndrome—comprises iritis with arthritis, urethritis, or colitis; (7) juvenile chronic arthritis—associated with potentially damaging recurrent iritis; (8) Wegener’s granulomatosis and other vasculitides—red eye can signify episcleritis, necrotizing scleritis, or potentially perforating keratitis; (9) systemic lupus erythematosus—also affects the coat of the eye, and can cause retinal vascular occlusions or ischaemic optic neuropathy.

Haematological disorders—retinal changes are common in haematological disorders, even if vision is normal. The eyes may be involved in (1) leukaemias—can cause retinal haemorrhages and Roth spots (focal collections of white cells), various ocular infiltrations, and the eye may be affected by infections, chemotherapy or radiotherapy; (2) lymphomas—may occur around or inside one or both eyes; (3) bleeding diatheses—may cause pronounced or repeated subconjunctival haemorrhage, hyphaema, or vitreous haemorrhage; (4) clotting tendencies—are associated with retinal vascular occlusion, especially venous; (5) sickling haemoglobinopathies—may cause retinal neovascularization with risk of haemorrhage, hence screening is recommended, with laser treatment if required.

Infectious diseases—the eye can be involved by many infections, including (1) bacterial—conjunctivitis, metastatic endophthalmitis, uveitis (tuberculosis, leprosy, syphilis); (2) chlamydial—genital serotypes cause acute conjunctivitis; trachoma is the most common cause of chronic conjunctivitis, affecting at least 600 million people worldwide, with about 6 million (preventably) blinded; (3) viral—most commonly adenoviral conjunctivitis; measles may cause a scarring corneal inflammation, an important cause of blindness in undernourished children; cytomegalovirus causes progressive retinitis with characteristic haemorrhages and patchy retinal necrosis, particularly in patients with AIDS; (4) fungal—metastatic endophthalmitis is usually caused by Candida albicans; infection in or around the orbit is characteristic of invasive mucormycosis; (5) protozoal—Toxoplasma gondii can cause congenital infection of the retina and underlying choroids; (6) helminth—onchocerciasis or ‘river blindness’ is still a common cause of blindness, particularly in Africa.

Thyroid disease—eye signs result either from imbalance of thyroid hormones, or from an immunological disorder of both the thyroid (Grave’s disease) and retro-orbital tissues, which is the commonest cause of proptosis (exophthalmos).

Inherited disorders—the eye may be discriminant in diagnosis of many inherited disorders, including Marfan’s syndrome (dislocated lenses), neurofibromatosis (Lisch nodules on the iris), and von Hippel–Lindau syndrome (retinal angiomas).

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