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Biomedical subjects

Gordon N Dutton

Publications and source records attributed to Gordon N Dutton.

10 recordsLinked to original sources
PubMed2007

Vincristine sulfate as a possible cause of optic neuropathy.

A 6-year-old boy with skin lesions suggestive of neurofibromatosis developed a frontotemporal primitive neuroectodermal tumor and was subsequently treated with surgery, craniospinal irradiation, and chemotherapy. After the sixth cycle of treatment with vincristine sulfate, 9 months after diagnosis, the child developed a rapidly progressive bilateral deterioration in visual acuity. Retinal appearances were consistent with optic neuropathy. Gene studies for neurocutaneous syndromes were negative. Brain imaging at this time showed no tumor progression, and in the absence of other etiologies, we implicate vincristine as a probable cause. Discontinuation of this particular agent has allowed bilateral improvement in visual acuity.

Child↗
PubMed2006

Deterioration of visual acuity associated with growth hormone therapy in a child with extreme short stature and high hypermetropia.

BACKGROUND: Growth hormone (GH) has long been implicated in the pathogenesis of diabetic retinopathy, although its precise role remains ill-defined. In 1998, an association between exogenous human GH and retinal pathology in non-diabetic subjects was described. CASE REPORT: A female child with extreme short stature of unknown aetiology (height -7.38 SD at 11.3 years) and severe hypermetropia developed retinopathy with visual deterioration during two separate empiric trials of GH therapy. On the first occasion, a relatively high dose of GH (10.5 mg/m2/week) administered from age 4.4 to age 4.7 years was associated with the development of central serous retinopathy, resulting in marked reduction in visual acuity. On cessation of GH, the macular oedema resolved, and visual acuity improved. At age 5.6 years, GH therapy was re-introduced at a lower dose (3.9 mg/m2/week) and her vision monitored closely. Bilateral retinal oedema recurred after 3 months, and GH therapy was stopped. Once again, the macular oedema regressed, and visual acuity improved following withdrawal of GH. These ophthalmic changes contra-indicated further GH therapy. CONCLUSION: We suggest that GH may be a risk factor in the development of retinopathy in certain non-diabetic patients, especially in the presence of a severe refractive error.

Child↗
PubMed2006

Vision in children with hydrocephalus.

Hydrocephalus in children has many aetiologies, and can cause multiple ophthalmic and visual disorders. This study sets out to detect and quantify visual and visuoperceptual dysfunction in children who have received surgical treatment for hydrocephalus with and without myelomeningocele, and to relate the results to the associated diagnoses and results from a comparison group. Seventy-five school-aged children (41 males, 34 females) with surgically-treated hydrocephalus and 140 comparison children (76 males, 64 females) matched for age and sex underwent comprehensive ophthalmologic examination. Median age at examination was 9 years and 4 months (range 7 y 4 mo-12 y 10 mo). Visual function deficits were identified in 83% (62/75) of the children with hydrocephalus. Visual impairment (binocular visual acuity <0.3) was found in 15% (11/73; comparison group 0%) but in none with myelomeningocele. Strabismus was found in 69% (51/74; comparison group 4% [5/140], p < 0.001), and refractive errors were found in 67% (47/70; comparison group 20% [28/140], p < 0.001). Cognitive visual dysfunction was identified in 59% (38/64; comparison group 3% [4/140], p < 0.001). These disorders were identified in various combinations and comprised impaired ability to plan movement through depth (e.g. going down a stair), impaired simultaneous perception, impaired perception of movement, impaired orientation, and (least frequently) impaired recognition. In this study, children with hydrocephalus associated with myelomeningocele were least commonly affected. Visual disorders were most frequent in those with epilepsy, cerebral palsy, and/or cognitive disability.

Adolescent↗
PubMed2006

Fusidic acid viscous eyedrops--an evaluation of pharmacodynamics, pharmacokinetics and clinical use for UK optometrists.

Recent changes in UK law have allowed UK-based optometrists to sell and supply fusidic acid viscous eyedrops, providing it is in the course of their professional activity and in an emergency. Alternatively, the optometrist may access fusidic acid viscous eyedrops, for a named patient, using a written order supplied to a pharmacy. This review provides details of the legal background to these changes, examines the common causes of a bacterial conjunctivitis, examines the mechanism of action of this narrow spectrum antibiotic as a bacteriostatic agent, reviews the susceptibility of common ocular isolates of bacteria to the drug and presents details of the expected pharmacokinetics of the viscous eyedrops. From this perspective, a systematic review is provided of the clinical studies which have investigated the use of fusidic acid viscous eyedrops and their outcome. The indicated use is generally for the treatment of bacterial conjunctivitis and/or blepharoconjunctivitis, especially that caused by Staphylococcus, but not Streptococcus or Haemophilus sp. (more likely associated with concurrent nasopharyngeal infections). The usual regimen for use is twice daily for 5-10 days, depending on severity, and can initially be used more intensively (four times per day). It may also be used for the management of corneal and conjunctival abrasions and foreign body injuries, or some cases of chronic blepharitis.

Administration, Topical↗
PubMed2005

Blindsight in children: does it exist and can it be used to help the child? Observations on a case series.

Damage to the occipital lobe of the brain results in hemianopia when unilateral, and cerebral blindness when bilateral. However, in some cases a degree of visual function persists in the blind visual field. This aim of this study was to describe this phenomenon of 'blindsight' in a cohort of children with brain-damage and to relate the clinical features to their visual evoked potentials. We performed a retrospective analysis of 541 case records of children referred to a tertiary vision-assessment clinic in the Royal Hospital for Sick Children, Glasgow, UK from 1992 to 2002. A total of 541 patients were analyzed (243 females, 298 males; age range 2 mo to 19 y 6 mo, mean 6 y 2 mo). In 19 children with profound visual impairment and four children with hemianopia (12 females, 11 males; age range 1 to 18 y, mean age 8 y 3 mo), evidence of perception of movement in the blind visual field was found and is described. Flash visual evoked potentials varied from no response to normal and was not correlated with visual behaviour. Recognition, detection, and use of this phenomenon in children is vital to their rehabilitation and interaction with their surroundings.

Adolescent↗
PubMed2003

Balint's syndrome in a 10-year-old male.

A 10-year-old male was referred with difficulties at school. He had particular difficulty with reading long words, following the sequence of text down a page, writing words in the correct order, writing words in line, and copying from the blackboard. He had a history of infective endocarditis complicated by intracerebral haemorrhage at the age of three years. Detailed history taking revealed symptoms typical of 'dorsal stream' pathology, namely a deficit of 'vision for action'. This included a spatial disorder of attention (simultanagnosia), defective hand and foot movements under visual control (optic ataxia), and acquired oculomotor apraxia which are consistent with Balint's syndrome. Strategies were suggested for coping with the symptoms and one year later a distinct improvement in adapting to the disability was found.

Adaptation, Psychological↗
PubMed2003

Multifocal electroretinographic features of central retinal vein occlusion.

PURPOSE: To determine the features of wide-field multifocal electroretinography (WF-mfERG) recorded in patients with central retinal vein occlusion (CRVO) and to compare WF-mfERG responses of the affected and fellow eyes. In addition, WF-mfERG responses were also compared by using standard electroretinography (ERG). METHODS: WF-mfERG and ERG responses were recorded from both eyes of 56 patients with CRVO. The WF-mfERG responses, obtained using a custom-built system were grouped into central and peripheral rings. The P1 amplitudes, and P1 and N1 implicit times were grouped and averaged within both rings. Nonparametric statistical analysis was used to compare the ERG results from the affected and fellow eyes. The results were also compared with normative data (5% to 95% confidence limits). RESULTS: CRVO markedly affected all the parameters of the WF-mfERG. In the affected eyes, 98% of the central and 91% of the peripheral P1 implicit times fell outside the normal range, as opposed to 35% of the 30-Hz flicker implicit times. The WF-mfERG responses obtained from eyes with CRVO were significantly different (P<0.01) from those derived from the fellow eye. The central and peripheral P1 implicit times were also abnormal in 59.2% and 46.9% of the fellow eyes, respectively. CONCLUSIONS: WF-mfERG is more susceptible than the standard ERG to changes in the nonlinear dynamics of the eye due to the multiple frequencies of stimulation used to record WF-mfERG responses. WF-mfERG could be a sensitive indicator of the underlying disease affecting the retina in eyes with CRVO and may have a role in the clinical setting.

Adult↗
PubMedDate not supplied

Complex visual hallucinations in the visually impaired: the Charles Bonnet Syndrome.

Visually impaired patients may experience complex visual hallucinations, a condition known as the Charles Bonnet Syndrome. Patients usually possess insight into the unreality of their visual experiences, which are commonly pleasant but may sometimes cause distress. The hallucinations consist of well-defined, organized, and clear images over which the subject has little control. It is believed that they represent release phenomena due to de-afferentation of the visual association areas of the cerebral cortex, leading to a form of phantom vision. Cognitive defects, social isolation, and sensory deprivation have also been implicated in the etiology of this condition. This condition, which is most common in the elderly, frequently goes unrecognized in clinical practice, due to both lack of awareness among doctors and patients' reluctance to admit to hallucinatory experiences, for fear of being labeled mentally unstable. Furthermore, patients who comprehend the unreality of their hallucinations may be distressed by the real fear of imminent insanity. Sensitive and sympathetic history taking is essential to ascertain the existence of hallucinations. Reassurance and explanation that the visions are benign and do not signify mental illness have a powerful therapeutic effect. Hallucinatory activity may terminate spontaneously, on improving visual function or on addressing social isolation. There is no universally effective drug treatment but anticonvulsants may play a limited role in aborting the hallucinations. Physician awareness and empathy are the cornerstones of management.

Anticonvulsants↗