I See No Ships.
Causes of gradual vision loss
1.Painless loss
Refractive error - this is characterised by an improvement of the visual acuity with the use of a pinhole (if you don't have a specific occluder with pinholes, a biro point-sized hole in a stiff piece of cardboard will do). Refer to the optician.
Cataracts - the patient often complains of glare in dark conditions (and so difficulty in driving at night) and may complain that colours appear more dull than they used to. There may be an abnormal red reflex and, in advanced cases, the cataract may be visible to the naked eye (this is increasingly rare these days). Other aspects of the examination should be normal unless there is concurrent pathology. Refer routinely.
Age-related macular degeneration (AMD) - suspect AMD if the patient is aged >50 years and is presenting with either of the following symptoms, usually affecting one eye at a time:
Distortion of vision, where straight lines appear crooked or wavy.
Painless loss or blurring of central or near-central vision. The person may describe a black or grey patch affecting their central field of vision (scotoma).
Various other visual symptoms can occur, or AMD may be an incidental finding by an optometrist. Visual acuity on a Snellen chart may be normal or reduced. When viewing an Amsler chart (or graph paper), patients may see breaks, waviness, or missing portions of the lines. Refer urgently if AMD is suspected.
Chronic (primary) open-angle glaucoma - is most commonly picked up through screening. If it is so advanced that the patient is the first to notice it, very little can be done. It is characterised by a progressive peripheral visual field loss and 'cupping' of the optic discs (the central area of the optic disc enlarges and the peripheral rim thins out). The degree of urgency depends on how advanced the damage is.
Diabetic retinopathy - the problem may be due to the diabetic microvascular problems (ie exudates and haemorrhages), to associated pathology (eg, diabetic cataract) or unrelated pathology (eg, glaucoma). Refer promptly (within a week), as prompt treatment may prevent deterioration.
Compression of optic nerve or optic pathway - rare, but should be considered if there is a history of headaches and if you find any neurological or endocrinological abnormalities (eg, acromegaly) on examination. Look for a relative afferent pupillary defect (not usually present in the above conditions), a pale or swollen optic disc (the margins are not clear) and visual field defects.
Drugs, toxins or nutritional deficiency - eg:
Amiodarone - various effects on the eye
Antituberculous drugs - ethambutol and isoniazid (optic neuritis).
Hydroxychloroquine (maculopathy).
Systemic steroids (cataracts and glaucoma)
Phosphodiesterase inhibitors (eg, sildenafil).
Others drugs - tetracyclines (benign intracranial hypertension), isotretinoin, tamoxifen (various possible effects on vision).
Alcohol, smoking and nutritional deficiency - eg:
Tobacco-alcohol amblyopia.
Methanol poisoning.
Vitamin A deficiency (classically causes night blindness).
Hereditary retinal dystrophies are rare and, depending on the exact problem, present anywhere from early childhood to middle age. Some are rapidly progressing; others are very slow. Typical features particularly include poor night vision and intolerance to light. Poor appreciation of movement in the peripheral visual field may also be a feature. Ask about similar problems in family members (who may not have been diagnosed). Children should be referred more promptly than adults for whom a routine referral is fine. These patients will need genetic counselling as well as support where the prognosis is poor.
Cerebrovascular disease (stroke and TIA) - although these are likely to present acutely. TIA causing visual loss is termed amaurosis fugax.
Papilloedema - eg, from intracranial hypertension.
-----------------------
2. Painful loss
This is much rarer and tends to suggest a more sinister pathology such as:
A progressive neoplastic (eg, choroidal melanoma) or inflammatory process (eg, chorioretinitis).
A systemic problem (eg, sarcoidosis or collagen vascular disease).
Lesions on the optic nerve (eg, optic neuritis, granuloma or neuroma).
Intracranial pathology or masses (may present with headache, or with endocrine symptoms if a pituitary tumour).
Intracranial hypertension (may have headache).
All these patients should be referred. Referral is more urgent than with painless conditions and patients should really be seen within a few days.
If there is a problem, don't wait seek medical help.
---------------
Candid street shot Bergen, Norway.
I See No Ships.
Causes of gradual vision loss
1.Painless loss
Refractive error - this is characterised by an improvement of the visual acuity with the use of a pinhole (if you don't have a specific occluder with pinholes, a biro point-sized hole in a stiff piece of cardboard will do). Refer to the optician.
Cataracts - the patient often complains of glare in dark conditions (and so difficulty in driving at night) and may complain that colours appear more dull than they used to. There may be an abnormal red reflex and, in advanced cases, the cataract may be visible to the naked eye (this is increasingly rare these days). Other aspects of the examination should be normal unless there is concurrent pathology. Refer routinely.
Age-related macular degeneration (AMD) - suspect AMD if the patient is aged >50 years and is presenting with either of the following symptoms, usually affecting one eye at a time:
Distortion of vision, where straight lines appear crooked or wavy.
Painless loss or blurring of central or near-central vision. The person may describe a black or grey patch affecting their central field of vision (scotoma).
Various other visual symptoms can occur, or AMD may be an incidental finding by an optometrist. Visual acuity on a Snellen chart may be normal or reduced. When viewing an Amsler chart (or graph paper), patients may see breaks, waviness, or missing portions of the lines. Refer urgently if AMD is suspected.
Chronic (primary) open-angle glaucoma - is most commonly picked up through screening. If it is so advanced that the patient is the first to notice it, very little can be done. It is characterised by a progressive peripheral visual field loss and 'cupping' of the optic discs (the central area of the optic disc enlarges and the peripheral rim thins out). The degree of urgency depends on how advanced the damage is.
Diabetic retinopathy - the problem may be due to the diabetic microvascular problems (ie exudates and haemorrhages), to associated pathology (eg, diabetic cataract) or unrelated pathology (eg, glaucoma). Refer promptly (within a week), as prompt treatment may prevent deterioration.
Compression of optic nerve or optic pathway - rare, but should be considered if there is a history of headaches and if you find any neurological or endocrinological abnormalities (eg, acromegaly) on examination. Look for a relative afferent pupillary defect (not usually present in the above conditions), a pale or swollen optic disc (the margins are not clear) and visual field defects.
Drugs, toxins or nutritional deficiency - eg:
Amiodarone - various effects on the eye
Antituberculous drugs - ethambutol and isoniazid (optic neuritis).
Hydroxychloroquine (maculopathy).
Systemic steroids (cataracts and glaucoma)
Phosphodiesterase inhibitors (eg, sildenafil).
Others drugs - tetracyclines (benign intracranial hypertension), isotretinoin, tamoxifen (various possible effects on vision).
Alcohol, smoking and nutritional deficiency - eg:
Tobacco-alcohol amblyopia.
Methanol poisoning.
Vitamin A deficiency (classically causes night blindness).
Hereditary retinal dystrophies are rare and, depending on the exact problem, present anywhere from early childhood to middle age. Some are rapidly progressing; others are very slow. Typical features particularly include poor night vision and intolerance to light. Poor appreciation of movement in the peripheral visual field may also be a feature. Ask about similar problems in family members (who may not have been diagnosed). Children should be referred more promptly than adults for whom a routine referral is fine. These patients will need genetic counselling as well as support where the prognosis is poor.
Cerebrovascular disease (stroke and TIA) - although these are likely to present acutely. TIA causing visual loss is termed amaurosis fugax.
Papilloedema - eg, from intracranial hypertension.
-----------------------
2. Painful loss
This is much rarer and tends to suggest a more sinister pathology such as:
A progressive neoplastic (eg, choroidal melanoma) or inflammatory process (eg, chorioretinitis).
A systemic problem (eg, sarcoidosis or collagen vascular disease).
Lesions on the optic nerve (eg, optic neuritis, granuloma or neuroma).
Intracranial pathology or masses (may present with headache, or with endocrine symptoms if a pituitary tumour).
Intracranial hypertension (may have headache).
All these patients should be referred. Referral is more urgent than with painless conditions and patients should really be seen within a few days.
If there is a problem, don't wait seek medical help.
---------------
Candid street shot Bergen, Norway.