Aim: To investigate the relation between the clinical and electrophysiological abnormalities of patients undergoing visual evoked potential investigation for albinism. Methods: 40 subjects with a ...probable or possible clinical diagnosis of albinism underwent pattern appearance and/or flash visual evoked potential (VEP) examination. The VEP findings are correlated with the clinical features of albinism determined by clinical examination and orthoptic assessment. Results: The majority of patients with clinical evidence of albinism showed a contralateral predominance in the VEPs. There was close correlation between the clinical signs of albinism and the degree of contralateral VEP predominance. This manifested as an interhemispheric latency asymmetry to monocular pattern appearance stimulation but amplitude asymmetry to flash stimulation. The strongest correlation for pattern appearance interhemispheric latency difference was with foveal hypoplasia (rho = 0.58; p = 0.0003) followed by nystagmus (rho = 0.48; p = 0.0027) and iris transillumination (rho = 0.33; p = 0.039). The VEP abnormalities were of greater magnitude in those patients with most features of albinism. Several patients with apparently mild disorders of ocular pigmentation had small but significantly abnormal VEP latency asymmetries. Conclusion: There is a strong association between the magnitude of the interhemispheric latency asymmetry of the pattern appearance VEP, and of amplitude asymmetry of the flash VEP, with the clinical signs of albinism. The data are consistent with a spectrum of abnormalities in albinism involving both clinical expression and electrophysiological misrouting, which is wider than previously recognised.
We have attempted to use allografts of normal muscle precursor cells (mpc) to insert donor nuclei, containing a normal genome, into growing or regenerating skeletal muscle fibres of mice with an ...inherited deficiency of the enzyme phosphorylase kinase (PhK). Analysis of the glucose-6-phosphate isomerase (GPI) isoenzymes of treated muscles showed that myonuclei of donor origin became incorporated into host muscle fibres in 8 of 9 regenerating autografts, but PhK activity was found only in the 3 grafts into which the largest numbers (1-3 x 10(6)) of mpc had been implanted. Following injection of normal mpc into growing PhK-deficient skeletal muscle, mosaic fibres containing myonuclei of donor origin were detected in only 11 of 192 muscles examined from 64 mice, but, of these 11 muscles, 5 contained PhK activity detectable by two separate assays in a further 4 muscles activity was detected by one or other assay.
To investigate factors associated with early management of intermittent exotropia (X(T)) in hospital eye departments in the UK in a prospective cohort study.
An inception cohort of 460 children aged ...<12 years with previously untreated X(T) (mean age 3.6 years, 55.9% girls) was recruited from 26 UK hospital children's eye clinics and orthoptic departments. Participants received a standard ophthalmic examination at recruitment and orthoptic assessment at three-monthly intervals thereafter. The influence of severity of exotropia (control measured by Newcastle Control Score (NCS), and angle of strabismus, visual acuity and stereoacuity) and age on the type of management was investigated.
Within the first 12 months following recruitment, 297 (64.6%) children received no treatment, either for impaired visual acuity or for strabismus. Ninety-six (21%) children had treatment for impaired visual acuity. Eighty-nine (19.4%) received treatment for strabismus (22 of whom also received treatment for defective visual acuity); in 54 (11.7%) treatment was non-surgical and in 35 (7.6%) eye muscle surgery was performed. Children with poor (score 7-9) control of strabismus at recruitment were more likely to have surgery than children with good (score 1-3) control (p<0.001). Children who had no treatment were younger (mean age 3.38 years) than those who were treated (mean 4.07 years) (p<0.001). Stereoacuity and size of the angle of strabismus did not influence the type of management received.
X(T) can be a presenting sign of reduced visual acuity. Most children with well controlled X(T) receive no treatment within 12 months following presentation.
OBJECTIVE:The aim of this study was to describe growth during puberty in young people with vertically acquired HIV.
DESIGN:Pooled data from 12 paediatric HIV cohorts in Europe and Thailand.
...METHODS:One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1–10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters.
RESULTS:At ART initiation, median age and HAZ was 6.4 interquartile range (IQR)2.8, 9.0 years and −1.2 (IQR−2.3 to −0.2), respectively. Median follow-up was 9.1 (IQR6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20–0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21–1.78) years later in those starting with HAZ less than −3 compared with HAZ at least −1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than −1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least −1, there was no association with age. Girls and boys who initiated ART with HAZ at least −1 maintained a similar height to the WHO reference mean.
CONCLUSION:Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least −1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age.
...his thyroid function was normal, but erythrocyte sedimentation rate (ESR) and C reactive protein (CRP) were moderately elevated. Treatments have included systemic steroids, 2, 3 cytotoxic agents ...such as vinblastine, 4, 5 cyclophosphamide, doxorubicin and adriamycin, and also interferon alfa. 1, 6 Local radiotherapy to the orbits has been used. 7, 8 The results of treatment have been generally disappointing. Cladribine is a purine analogue that is toxic to monocytes. 9 Cladribine also destroys both resting and dividing lymphocytes, 10 and causes T cell depletion. 11 In 1999, Saven and Burian 12 described encouraging responses to cladribine in 13 patients with adult Langerhans cell histiocytosis.
A failure of human foveal development only occurs in two genetically determined conditions; aniridia (Pax6 mutation) and albinism (tyrosinase mutation). The chiasmatic pathways from this region are ...disrupted in albinism and central retinal blood vessel patterns are abnormal. It is assumed that these three abnormalities have a common mechanism. Here we investigate whether similar abnormalities are present in subjects with aniridia. Using fundus photographs it is shown that abnormal blood vessel patterns are present in aniridia, but these significantly differ from those in albinos. Using electrophysiological techniques, abnormal hemispheric projections through the chiasm are demonstrated in albinos, but aniridics do not differ from normal subjects. These results demonstrate that although mutations in Pax6 and tyrosinase both affect central retinal development, they have a fundamentally different impact on the formation of the retinal vasculature and the projections from this region. This strongly suggests that separate mechanisms regulate the development of the central retina and decussation patterns at the optic chiasm.
Intensive occlusion therapy for amblyopia Dorey, Suzanne E; Adams, Gillian G W; Lee, John P ...
British journal of ophthalmology,
03/2001, Letnik:
85, Številka:
3
Journal Article
Recenzirano
Odprti dostop
AIM To study the effects of supervised inpatient occlusion treatment for amblyopia in children who had failed to respond to outpatient treatment. METHODS A retrospective study of 39 children admitted ...to a paediatric ophthalmic ward for 5 days of supervised intensive occlusion therapy having previously failed to respond to outpatient occlusion. Visual acuity of amblyopic and fellow eyes was recorded at each clinic visit before admission, daily during admission, and at each outpatient visit after discharge. RESULTS There was no significant overall improvement in visual acuity during a mean of 9 months of attempted outpatient occlusion before admission. During the 5 days of admission 26 children (67%) gained at least one line of acuity in their amblyopic eye and five (13%) gained three or more lines (mean gain 1.03 Snellen lines). The acuities of both the amblyopic and fellow eyes subsequently improved with continuing part time patching as an outpatient, including in nine of the children who did not respond during admission. At the last recorded visit, at a median time of 14 months after discharge, 13 (33%) of the patients had an acuity of at least 6/12 in their amblyopic eye. CONCLUSIONS The acuity of amblyopic eyes did not improve without effective treatment. Subsequent supervised inpatient occlusion therapy was effective in the majority of the children.
Aims: To examine the effect of a unilateral full thickness macular hole on sensory and motor binocular function and to study recovery after successful surgical closure. Methods: Twenty eight ...consecutive patients undergoing surgery for a unilateral macular hole underwent orthoptic examination, including measurements of Titmus and TNO stereoacuity and motor fusion range before surgery. Twenty three patients had successful anatomical closure. Fifteen of these patients, who had both improved acuity in the operated eye following surgery and were available for further testing, underwent repeat orthoptic assessment 2–7 months after surgery. Results: In all patients stereoacuity was reduced before surgery, but few patients were subjectively aware of a deficit of depth perception affecting their everyday life. In those patients with improved Snellen acuity after surgery, stereoacuity measured by the Titmus stereotest also improved significantly, but not that measured by the TNO test. Two patients were aware of a subjective improvement in depth perception. Motor fusion was markedly reduced compared to normal before surgery, with only limited recovery after surgery. Conclusion: A unilateral macular hole notably reduced both stereoacuity and motor fusion. Successful closure improved the deficit in stereoacuity associated with the hole when measured by a stereotest using contoured stimuli. The majority of patients were not subjectively aware of the deficit in stereoacuity or its improvement following surgery.
A deficiency of melanin in the retinal pigment epithelium, which regulates the development of neural retina, leads to chiasmal misrouting such that the uncrossed pathway (to the ipsilateral ...hemisphere) is reduced relative to the crossed pathway (to the contralateral hemisphere). This study examines age‐related changes in the flash and pattern appearance visual evoked potentials (VEP) of human albinos. Scalp recorded cortical VEPs to flash (FVEP) and pattern appearance stimulation were recorded in 58 albino (8 months to 60 years) and 34 normal subjects (4–55 years). VEPs were analysed by amplitude and latency. The contralateral hemisphere FVEP amplitude decreased with age in albino subjects, as in both hemispheres in normals. However, the ipsilateral hemisphere FVEP amplitude was significantly lower in young albino subjects, initially giving a marked interhemispheric asymmetry, but this normalized with age. Significant interhemispheric FVEP latency asymmetries were not observed. The contralateral pattern appearance VEP latency in albino subjects decreased with age, as in both hemispheres in normals; the ipsilateral latency increased significantly with age. Significant interhemispheric pattern appearance VEP amplitude asymmetries were not observed. These novel and unexpected observations indicate significant age‐related changes in the retinocortical pathways of the human albino. These changes have implications for our understanding of development and plasticity of the central visual pathways.
Studies in nonhuman primates show that monocular visual deprivation starting at different ages has different effects on cells in the parvocellular and magnocellular laminae of the lateral geniculate ...nucleus. The present study used color and luminance contrast sensitivity (CS) measurements to look for differences in parvocellular- and magnocellular-related visual function in human subjects with strabismic amblyopia.
Fifteen subjects with early- and 14 with late-onset strabismic amblyopia and similar ranges of visual acuity were studied, together with 15 subjects with normal vision. Contrast sensitivities were measured to an equiluminant (L-M cone-modulated) grating with slow onset and an achromatic (L+M cone-modulated) 0.8-cpd grating with rapid onset using an adaptive
Luminance and color CS were lower in the amblyopic eyes than in the fellow eyes of all amblyopes. For luminance CS, this was due both to an increase in sensitivity of the fellow eye and to a reduction in sensitivity in the amblyopic eye. Color CS was greatly reduced in the amblyopic and fellow eyes of subjects with strabismic amblyopia of early- and late onset compared with subjects with normal vision. The reduction in color CS compared with luminance CS was significantly greater in eyes with late- rather than early-onset amblyopia.
Parvocellular and magnocellular function are differentially affected in the amblyopic and fellow eyes of subjects with strabismic amblyopia. The difference is more marked in late-onset amblyopia than in early-onset amblyopia.
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