Systemic Disease and the Eye
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Direct answer
Systemic diseases reach the eye through microvasculature, immunity and deposition, and the fundus and anterior segment often show the diagnosis before the physician confirms it: thyroid eye disease produces proptosis with lid retraction and restrictive diplopia; diabetes and hypertension write their severity on the retina; tuberculosis and sarcoidosis seed uveitis; Wilson disease deposits copper in Descemet's membrane as the Kayser-Fleischer ring; and connective-tissue disease presents with dry eyes, scleritis or peripheral ulcerative keratitis. For the FMGE, the topic is a matrix of one-line associations — Eales' disease in a young Indian man with recurrent vitreous haemorrhage, lens subluxation upward in Marfan syndrome and downward in homocystinuria, a Hutchinson-sign zoster rash threatening the eye. Learning the matrix by system, not by disease, makes it retrievable under examination pressure.
What you must remember
- Thyroid eye disease: lid retraction and lagophthalmos, axial proptosis, restrictive myopathy (inferior rectus most often, limiting upgaze), compressive optic neuropathy in the tight orbit; smoking is the strongest modifiable risk, and management runs from selenium and lubricants to high-dose steroids, orbital radiotherapy and decompression.
- Eales' disease: idiopathic retinal periphlebitis with recurrent vitreous haemorrhage in young adult Indian men — a classic one-liner; photocoagulation of ischaemic retina and vitrectomy for non-clearing haemorrhage.
- Wilson disease: Kayser-Fleischer ring of copper in Descemet's membrane at the limbus, best seen on gonioscopy; accompanied by sunflower cataract.
- Herpes zoster ophthalmicus: vesicles on the tip of the nose (Hutchinson sign) predict ocular involvement — uveitis, keratitis and post-herpetic neuralgia; treat with oral acyclovir.
- Sarcoidosis: granulomatous uveitis with mutton-fat keratic precipitates, candle-wax drippings along retinal veins, and lacrimal gland enlargement; chest radiograph and serum calcium anchor the work-up.
- Tuberculosis: choroidal tubercles on fundoscopy in miliary disease, and Eales-type vasculitis in the Indian clinic; rheumatoid disease causes keratoconjunctivitis sicca, scleritis and peripheral ulcerative keratitis.
- Marfan syndrome subluxates the lens upward and out; homocystinuria downward and in, with the added thrombosis risk that changes squint and cataract surgery planning.
- Malignancies announce themselves in the eye: leukaemia with retinal haemorrhages and Roth spots (also in endocarditis), lymphoma with vitreous cells and subretinal infiltrates, and breast and lung cancer with choroidal metastases.
A proptosis case that organises the whole topic
A 45-year-old woman presents with bulging eyes, watering and morning grittiness; her husband has noticed a stare. Work the examination systematically and the system reveals itself. Vision is 6/9 bilaterally, but colour vision is muted on the right. The lids are retracted with lag on downgaze, and the conjunctiva is chemotic over the lower limbus. Hertel exophthalmometry confirms axial proptosis, and she cannot elevate either eye beyond the midline — tight inferior recti. The orbit is crowded on computed tomography with spindle-shaped muscle enlargement, tendons spared — the picture of thyroid eye disease, and the muted colour vision flags early compressive optic neuropathy. Management steps through severity: smoking cessation and selenium for mild disease, lubricants and lid taping at night for exposure, high-dose intravenous steroids for optic neuropathy, and orbital decompression when medical therapy fails, with strabismus surgery after the orbit is stable and decompressed. The same structure — look at the lid, the motility, the optic nerve, the fundus — organises the rest of the matrix: in Marfan syndrome the same exam finds the lens in the pupil, subluxed up; in Wilson disease the slit lamp and gonioscope find the golden-brown ring; in leukaemia the fundus shows white-centred haemorrhages. One framework, many systems.
How the exam frames it
This topic is examined as association recall under time pressure: "young male, recurrent vitreous haemorrhage, periphlebitis — Eales' disease"; "ring at Descemet's membrane — Wilson"; "lens subluxation downward — homocystinuria"; "nose-tip vesicles with eye pain — zoster ophthalmicus with Hutchinson sign". The higher-value questions add management or mechanism: why thyroid eye disease restricts upgaze (tight inferior rectus, not nerve palsy), why hyperthyroid patients with lid retraction still need lubricants at night (lagophthalmos and exposure), and why sarcoid uveitis warrants a chest radiograph. Candidates who group the associations by system rather than memorising isolated pairs answer both stems and vivas faster.
Frequently asked questions
What are the ocular features of thyroid eye disease?
Lid retraction and lag, axial proptosis, restrictive extraocular myopathy (inferior rectus limiting upgaze), exposure keratopathy and compressive optic neuropathy; smoking worsens severity.
Which disease causes recurrent vitreous haemorrhage in young Indian men?
Eales disease, an idiopathic retinal periphlebitis producing peripheral ischaemia, neovascularisation and recurrent bleeds, treated with photocoagulation and vitrectomy when needed.
What is the Kayser-Fleischer ring?
Copper deposited in Descemet's membrane at the corneal periphery in Wilson disease, golden-brown on slit lamp and best detected by gonioscopy.
How do Marfan syndrome and homocystinuria differ in the eye?
Both subluxate the lens — upward and outward in Marfan syndrome, downward and inward in homocystinuria, which also carries thrombosis risk affecting surgical planning.
Which fundus sign appears in both endocarditis and leukaemia?
Roth spots — white-centred retinal haemorrhages — seen in infective endocarditis, leukaemia and anaemia.