INTRODUCTION
Patients who have difficulty seeing will more often than not first seek the advice of an optometrist or ophthalmologist. Even if they first consult a general physician or a neurologist they will in all likelihood be sent to an eye specialist to answer the question: “Why can’t this patient see well?”
A small proportion of such patients will have visual loss due to neurological disease. While testing acuity, colour vision and visual fields will usually identify such patients, there will remain some with normal acuity and visual fields who have cerebral disease affecting vision.
Even amongst those patients who are known to have disease affecting visual areas of the brain and therefore under the care of the neurologists there are those who have a greater visual disability than would be predicted from their visual acuity and visual field measurements. These patients may also be referred to an optometrist of ophthalmologist for an explanation of their symptoms and assistance with rehabilitation. This collection of tests is designed to allow vision specialists without any detailed knowledge of neuropsychology to probe the higher visual areas of the brain
Cerebral lesions affecting the occipital or parietal lobes result in problems with the perception of faces, pictures, colours and with the ability to read fluently. This screening test is designed to detect visual impairments in individuals with normal (corrected) or near-normal vision. Each of these tests focus on a different aspect of early visual processing by cortical centres. A description of the aim of every test along with the instructions to the subject and an indication of its significance can be found on the instructions page. These tests are simple to administer and make minimal demands on the testee. An individual who has any difficulty with any of these tests should undergo appropriate neurological and neuropsychological testing.
As a neuro-ophthalmologist one of us (GTP) is all too familiar with making a diagnosis of cortical loss which is encountered most commonly in patients with bilateral occipital/parietal ischaemic disease after a stroke or head injury, with posterior forms of Alzheimer’s disease or prion disease or with space occupying lesions. It is anticipated that this test will, as with colour test plates and stereo tests be employed for patients with visual symptoms that cannot be explained by a routine ophthalmological, optometric or neurological examination.
A small proportion of such patients will have visual loss due to neurological disease. While testing acuity, colour vision and visual fields will usually identify such patients, there will remain some with normal acuity and visual fields who have cerebral disease affecting vision.
Even amongst those patients who are known to have disease affecting visual areas of the brain and therefore under the care of the neurologists there are those who have a greater visual disability than would be predicted from their visual acuity and visual field measurements. These patients may also be referred to an optometrist of ophthalmologist for an explanation of their symptoms and assistance with rehabilitation. This collection of tests is designed to allow vision specialists without any detailed knowledge of neuropsychology to probe the higher visual areas of the brain
Cerebral lesions affecting the occipital or parietal lobes result in problems with the perception of faces, pictures, colours and with the ability to read fluently. This screening test is designed to detect visual impairments in individuals with normal (corrected) or near-normal vision. Each of these tests focus on a different aspect of early visual processing by cortical centres. A description of the aim of every test along with the instructions to the subject and an indication of its significance can be found on the instructions page. These tests are simple to administer and make minimal demands on the testee. An individual who has any difficulty with any of these tests should undergo appropriate neurological and neuropsychological testing.
As a neuro-ophthalmologist one of us (GTP) is all too familiar with making a diagnosis of cortical loss which is encountered most commonly in patients with bilateral occipital/parietal ischaemic disease after a stroke or head injury, with posterior forms of Alzheimer’s disease or prion disease or with space occupying lesions. It is anticipated that this test will, as with colour test plates and stereo tests be employed for patients with visual symptoms that cannot be explained by a routine ophthalmological, optometric or neurological examination.
Selected References
- McNeil J. and Warrington E.K., (1991) Prosopagnosia: a reclassification. Quarterly Journal of Experimental Psychology, 43a (2), pp. 267-287.
- De Renzi E., (1983) Disorders of space exploration and cognition. Chichester Wiley.
- Patterson K.E., Marshall J.C., and Coltheart M. [eds], (1985) Surface dyslexia: neuropsychological and cognitive studies of phonological reading. Laurence Erlbaum Associates Limited, London
- Plant G.T., (1999) Disorders of higher visual function, Oxford Textbook of Ophthalmology, vol 2, pp. 859-862, D L Easty and J M Sparrow [eds] Oxford University Press, Oxford.
- Plant G.T. and Tripathy S., (1997) Effect on vision of foveal contour interactions. Lancet, 349, no. 9061, pp.1296-1297
- Warrington E.K., (1967) Visual deficits associated with occipital lobe lesions in man. Expirimental Brain Research, Supplementum 11, pp. 247-261
- Warrington E.K and James M., (1967) Disorders of visual perception in patients with localised cerebral lesions. Neuropsychologia 5, pp. 253-266
- Warrington E.K and James M., (1988) Visual apperceptive agnosia: a clinico-anatomical study of three cases. Cortex, 24, pp. 13-32
- Warrington E.K and James M., (1991) The Visual Object and Space Perception Battery. Thames Valley Test Company, Bury St Edmunds, England.
- Warrington E.K and Taylor A.M, (1973) Contribution of the right Parietal Lobe to Object Recognition Cortex 9 152-164
- Warrington E.K and Taylor A.M, (1978) Two categorical stages of object recognition Perception 7 695-705