OCULAR MANIFESTATIONS OF SYSTEMIC DISEASESThe eye is intimately linked not only with the adjacent structures but also with the remote organs of the body. Ocular manifestations are so common in many systemic diseases that the ophthalmoscope is an essential part of the of every competent physician. No medical examination is really thorough or complete without examination of the fundus.

METABOLIC DISORDERSDIABETES MELLITUSDIABETES MELLITUS Ocular complications are common in diabetes, but bear little relation to the severity of the disease. They depend much more on the duration of the diabetes and commonly occur in long-standing cases. Lesions of the lids.—Diabetes lowers the resistance of the patient to pyogenic infections and predisposes to recurrent styes.Lesions of the Conjunctiva and the Cornea.—Conjunctivitis and keratitis are possible complications.Lesions of the Iris.—The iris may exhibit the following lesions :Rubeosis lridis Edema and Vesiculation of the Pigment Epithelium. — This leads to easy scattering of the iris pigment by mild trauma.

Transient Visual Disturbances; Transient Refractive Changes. Accommodation Disorders.—Weakness of accommodation may result when the ciliary muscle becomes weakened by peripheral neuritis involving its nerve supply.Subjective Visual Disturbances. — Amaurosis may occur in severe cases of diabetes. Disturbances of the visual cortex may lead to misty vision and to lashes of light which patients may experience after an overdose of insulin. .

Diabetic Cataract. Diabetic Retinopathy. Intra-Ocular Haemorrhage. This is due to rubeosis iridis. Retrobulbar Optic Neuritis.—Diabetic optic neuritis is usually bilateral, rapid in onset and often painless. Ocular Tension.—Hypotony may occur in cases of diabetic coma. Extra-Ocular Muscle Palsies.—Paralysis of one or more of the extrinsic ocular muscles may occur.

DISTURBANCES OF CALCIUM METABOLISMHypocalcemiaHypocalcemia Cataract. Myopia. VITAMIN DEFICIENCIESVITAMIN A DEFICIENCYVITAMIN A DEFICIENCYThe chief ocular manifestations of Vitamin A deficiency are defective night-vision and xerophthalmia. Blepharitis, recurrent chalaiza and styes, chronic conjunctivitis and keratomalatia are also commonVITAMIN B DEFICIENCYVITAMIN B DEFICIENCY Vitamin B1 Deficiency Conjunctivitis. Nystagmus. Papilloedema. Retinal haemorrhages. Extra-ocular muscle paralysis.

Vitamin B2 (Riboflavine) Deficiency Photophobia together with itching and burning sensations.Conjunctivitis is a typical manifestation.Peripheral vascularization of the cornea is often present.Cataract can be produced experimentally in riboflavin deficiency.Fundus changes consist of hyperaemia of the disc, papilloedema, VITAMIN C DEFICIENCYVITAMIN C DEFICIENCYOrbital haemorrhage. Conjunctival and palpebral haemorrhages. Keratoconjunctivitis. Cataract. Retinal hemorrhages.

VITAMIN D DEFICIENCYVITAMIN D DEFICIENCYLamellar cataract.High myopia, spring catarrh, phlyctenular keratoconjunctivitis and conical cornea

DISEASES OF THE ENDOCRINE GLANDPITUITARY GLANDPITUITARY GLANDHeadache— It is often bitemporal and of a "bursting" type. Visual Field Defects. —The loss of fields to colours is always more extensive than to white.Typically, the field defect commences in the periphery of the upper temporal quadrant and extends downwards to produce the typical bitemporal hemianopia.

Optic Atrophy but occasionally papilladema.Ocular Palsy due to the pressure effects by a laterally growing tumour on the oculomotor, trochlear or abducent nerves.Slight Exophthalmos may occur as a result of a disturbed production of thyrotropic hormone.

PINEAL GLANDPINEAL GLAND Severe headache and papilloedema are early manifestations, caused by the blockage of cerebro-spinal fluid circulation at the aqueduct of SylvianOcular palsies and ptosis often occur.Failure of the pupillary light response may develop as a result of pressure on the pathway of the pupillarlight reflex.

THYROID GLANDTHYROID GLAND Manifestations of Thyroid Hypofunction (Myxoedema)Puffiness of the eyelids.Loss of hairs of the outer half of the eyebrows. Bilateral Manifestations of Thyroid Hyperfunction (thyrotoxicosis retrobulbar neuritis and optic atrophy may occur.Exophthalmos which may lead to exposure keratitis.Lid retraction and lid lag of the upper eyelid.Odema of the eyelids.Pigmentation of the eyelids.Congestion of the conjunctiva vessels.Ocular palsies, especially affecting the superior rectus muscles leading to diplopia.Convergence insufficiency.Fundus changes include visible arterial pulsation, papilloedcma, partial optic atrophy, exudates in the posterior pole and degeneration of the macula.Rarely, retrobulbar neuritis.

DISEASES OF THE KIDNEYSRenal Retinopathy The retinopathy occurs typically in type II nephritis and sometimes after type 1 nephritis. Ophthalmoscopic Signs of Renal (Hypertensive) Ophthalmoscopic Signs of Renal (Hypertensive) RetinopathyRetinopathyConstriction of the Retinal Arteriols.

Generalized Retinal Edema with Edema of the Optic Disc. Numerous Cotton-Wool Patches. Retinal Haemorrhages. Hard White Exudates Exudative Retinal Detachment. Crystalline Retinal Deposits

TEMPORAL ARTERITIS.Ocular manifestations are present in about 50% of cases. The eye signs include temporary incomplete external ophthalmoplegia, serve optic neuritis and unilateral, but sometimes bilateral, occlusion of the central retinal artery leading to complete blindness. PERIARTERTTIS NODOSAPeriarteritis nodosa is an inflammatory disease of the coats of the small and medium-sized arteries of the body with inflammatory changes around the vessels. Ocular manifestations include angiospastic retinopathy, central retinal artery occlusion, iritis, keratitis, ring ulcer of the cornea, scleritis and extra-ocular muscle palsy. Systemic corticosteroids are of some values but the prognosis is usually bad.

RHEUMATOID ARTHRITISThe ocular manifestations of rheumatoid arthritis include commonly iridocyclitis, but rarely scleromalcia performs.

Ankylosing spondylitis.—The disease affects the joints of the spine and is associated with recurrent iridocyclitis. CHRONIC GRANULOMATOUS DISEASESTUBERCULOSISConjunctivitis. Phlyctenular keratoconjunctivitis. Interstitial keratitis. Sclerosing keratitis. Anterior uveitis. Nodules on the iris. Miliary tuberculosis. Choroiditis (tuberculoma) Perivasculitis retina(Eales' disease). Optic neuritis.Dacryoadenitis. Dacryocystitis.

SYPHILISChancre of the lid. Gumma of the tarsal plate.Gumma of the lacrimal gland.

Chancre of the conjunctiva.Interstitial keratitis. Iridocyditis.

Congenital (lamellar) cataract.Choroido-retinitis. Optic neuritis.Primary optic atrophy.

Paralysis of the extrinsic ocular muscles. LEPROSYNodules on eyelids or anesthetic patches.Nodules on the conjunctiva or sclera.Interstitial keratitis, Superficial punctate keratitis, Leprotic pannus.Iritis, Secondary glaucoma

SARCOIDOSISSarcoid nodules on the eyelids.Painless nodular enlargement of the lacrimal glands which may be unilateral or bilateral. Episcleral nodules.Nodular iritis.Nodular choroido-retinitis.

DISEASES OF THE MUSCLESMYASTHENIA GRAVISMyasthenia gravis is a chronic neuromuscular disease characterised by fatigue and exhaustion of the muscular system marked by progressive paralysis of muscles without sensory disturbance or motor nerve paralysis, The disease is presumably due to a curare-like block, interfering with the normal action of acetylcholine at the myoneural junction. the disease generally commences the levator palpebrae superioris muscle leading to ptosis. Later, the disease involves the extra-ocular muscles, Diplopia.Convergence insufficiency. Weakness of accommodation.

ReferencesParson’s diseases of the eye