We identified 50 patients between June 2010 and February 2012. Two patients had failed to attend, and for one no notes were obtainable. Therefore, 47 patients were included in the analysis. Mean age of patients was 76.2 (range 51–92) with slightly more women than men: 53% (25/47) and 47% (22/47), respectively.
The nature of presenting complaints is given in . Almost half (47%, 22/47) the patients attended with one main presenting complaint. An almost equal number (49%, 23/47) had two or more presenting complaints; 26% (12/47) had two main complaints; 23% (11/47) had three or more. The remaining 4% (2/47) were asymptomatic, having been referred with abnormal examination findings. A significant number of patients had pre-existing neurological, ophthalmic, or psychiatric comorbidities ().
Presenting complaints and comorbidities of patients attending Visual Perception clinic
Before clinic, 72% (34/47) of patients had seen an ophthalmologist, of whom 17% (8/47) had also seen a neurologist, and 15% (7/47) a psychiatrist. One person (2%) had consulted all three with regard to their visual symptoms. Referrals to clinic were made primarily by ophthalmology (57.4%, 27/47), followed by the family practitioner (30%, 14/47), psychiatry (9%, 4/47), and finally neurology (4%, 2/47).
Cognitive assessment was clinically indicated in 43% (20/47) patients. Assessments included the mini-mental-state examination (MMSE),15
the revised Addenbrookes cognitive examination,16
and the Montreal Cognitive assessment (MoCA).17
A significant number of patients (68%, 32/47) had a diagnosis of cognitive impairment. Of these, 50% (16/32) were new diagnoses.
After clinic attendance, a significant number of patients were given a new diagnosis. There was also an increase in the number of diagnoses with a neuropsychiatric component, and a concomitant decrease in the number of purely ophthalmological diagnoses ().
Diagnosis before and after clinic attendance
Brain imaging was performed as clinically indicated in 21% (10/47) patients; including computerised tomography (CT) (6%, 3/47) and magnetic resonance imaging (MRI) (15%, 7/47). Two patients (4%) had a DatSCAN, which is a single photon emission CT (SPECT) scan carried out with the dopaminergic presynaptic ligand FP-CIT. This enables visualisation of the distribution of dopamine transportation in the striatum and is useful to aid diagnosis of conditions such as Lewy body dementia and Parkinson's disease. One patient (2%) had a Tc-99m HMPAO SPECT perfusion scan. Tc-99m HMPAO is a well-established isotype useful for examining regional cerebral blood flow.
Following clinic attendance, 43% (20/47) patients were referred for continuing care to other clinics: 9% (4/47) to neurology, 4% (2/47) to ophthalmology, 11% (5/47) to memory clinic, 11% (5/47) to psychiatry, 6% (3/47) to optometry, and 2% (1/47) to ear nose and throat. Treatment was initiated in clinic for 36% (17/47) of patients: 13% (6/47) had a medication change, 4% (2/47) underwent ophthalmic surgery, 9% (4/47) had optical correction, and 11% (5/47) received counselling or other social input.
A 61-year-old female patient presented to her family practitioner in August 2010 with dizziness, blurring of vision, and seeing lights, with a normal ophthalmic examination. She was referred to a general eye clinic where no explanation was found for her symptoms. CT head was normal. She reattended the eye clinic in October 2010 with deteriorating night vision and intermittent diplopia, and was examined by a second consultant. She was found to have an incongruous left hemianopia and a provisional diagnosis of retinal dystrophy was made. However, she had a normal electroretinogram and normal retinal appearance.
She was referred to the Visual Perception clinic June 2011, where she described bumping into things on her left, struggling with direction sense and orientation difficulties. Cognitive test scores were 26/30 on MMSE and 71/100 on Addenbrooke's, with significant visuospatial deficit (). MRI showed bilateral symmetrical posterior parietal and occipital atrophy. A provisional diagnosis of atypical Alzheimer's disease with a profound visual element was made. Tc-99m HMPAO SPECT perfusion scan showed moderate posterior hypoperfusion in the dorsal occipital lobe (), in keeping with a diagnosis of posterior cortical atrophy (visual variant) Alzheimer's disease.
Figure 1 Tests of visuoconstruction from the Revised Addenbrooke's Cognitive Examination as performed by patient described in case 1: (a) Interlocking pentagons (Original left, patient copy right). (b) Necker cube (original left, patient copy right). (c) Clock (more ...)
Figure 2 Case 1: Tc-99m HMPAO SPECT with coronal (left), sagittal (centre), and horizontal (right) sections. Bilateral parieto-occipital perfusion deficit which is slightly more marked in the right hemisphere (arrows). There is also some bilateral medial temporal (more ...) Patient 2
A 77-year-old female patient with a history of previous retinal detachment was seen by her family practitioner complaining of seeing white lines and flowers. Her optician was unable to find an explanation for her symptoms but noted mild to moderate cataract. She was seen in the Visual Perception Clinic November 2010, where examination findings and CT scan were unremarkable and her visual acuities were 6/18 on the right and 6/12 on the left. We reviewed her in March 2011 with worsening symptoms including right sided frontal-temporal headaches and patterned hallucinations. She showed cognitive impairment with a test score of 17/30 on the MoCA. We arranged a DaTSCAN that showed reduced tracer uptake in the left putamen () consistent with probable dementia with Lewy Bodies. Her care is being continued under old-age psychiatry.
Case 2: FP-CIT presynaptic dopamine imaging scan (DaTSCAN). Horizontal sections showing reduced tracer uptake in the left putamen (arrow) consistent with the diagnosis of dementia with Lewy Bodies.
A 73-year-old male was referred by his optician late in 2005 with symptoms of a left visual field deficit. Humphreys and Goldmann field testing gave inconsistent results and he was referred to glaucoma clinic in early 2006. In 2007 he was referred with visual loss post total hip replacement, and examination revealed a right hemianopia. In 2008 and 2009, imaging performed for increasing forgetfulness showed a chronic left frontal infarct and generalised brain atrophy on CT and severe hypoperfusion in the left parieto-occipital, frontal, and medial temporal lobe on Tc-99m HMPAO SPECT perfusion imaging. He re-presented in 2010 to Neurology with visual hallucinations. In June 2011 he presented to general eye clinic with deteriorating visual acuity and continuing hallucinations. He was diagnosed with bilateral cataract and underwent left phaecoemulsification, but had no significant symptom relief.
In October 2011 he re-presented with deterioration of distance vision, losing his way around his home and difficulty in finding clothes and recognising faces, on a background of poor memory and continuing hallucinations. At this stage he was referred to Visual Perception Clinic. Examination revealed a right homonymous hemianopia, simultanagnosia, and central visual loss. A provisional diagnosis was made of vascular dementia with Balint's syndrome. The patient and his wife were counselled and indicated that despite a lack of management options, their primary motivation was to improve understanding of his symptoms. An MRI scan showed bilateral occipital atrophy. A Tc-99m HMPAO SPECT perfusion scan was therefore organised in order to look for any areas of hypoperfusion. This showed bilateral perfusion deficiencies in the occipital and parietal regions, right more severe than left. This pattern of bilateral, asymmetric cerebral hypoperfusion of the parieto-occipito regions is typical of visual variant Alzheimer's disease (posterior cortical atrophy).