Biomedical subjects

T J Buckingham

Publications and source records attributed to T J Buckingham.

3 recordsLinked to original sources

PubMed1998

Movement hyperacuity in childhood amblyopia.

BACKGROUND: Amblyopia results in deficits in a number of visual functions in both the amblyopic and dominant eye. The present work describes oscillatory movement displacement thresholds (OMDT) in childhood amblyopia. METHODS: The OMDT from the dominant and amblyopic eyes of 50 orthoptic patients (aged 74 (SD 16) months) were compared with those from a group of 24 controls (79 (21) months). OMDT were measured using a forced choice staircase procedure. Subjects were asked to identify which of the computer controlled monitors displayed the oscillating stimulus. Visual acuity and stereoscopic responses were noted from clinical records. RESULTS: Amblyopic children demonstrating stereopsis showed no significant OMDT deficit in the amblyopic eye. Those children having no stereopsis had elevated OMDT in the amblyopic eye (p < 0.05). Results suggest that the dominant eye of children with amblyopia may also have a pattern of visual development which is anomalous (difference in correlation coefficient with age; p < 0.05). CONCLUSION: OMDT deficits demonstrated in some amblyopic eyes indicate that amblyopia is incompletely described by its "clinical" definition. Results suggest that the dominant eye in those with unilateral amblyopia may not be "normal".

Aging↗

PubMed1996

The comparative development of movement hyperacuity and visual acuity in children.

Oscillatory movement displacement thresholds (OMDT) have been suggested as a test of neural integrity of the visual system, detecting deficit even in the presence of normal resolution. Both OMDT and visual resolution were measured in 153 normal children between the ages of 2.2 and 13 yr (mean = 6.2 +/- 2.8 yr). OMDT were obtained using a computer-generated vertical bar stimulus oscillating at 4 Hz. Visual acuity was determined using a Polymetric Vision Assessment technique (PVA) where a single letter optotype is presented at increasing viewing distance to determine threshold. OMDT is a hyperacuity at all ages, exhibiting improving thresholds up to around 8 yr of age when results are typical of adults. PVA thresholds improve less markedly over the range measured, appearing mature by 6-7 yr. Correlation between OMDT hyperacuity and visual acuity is poor, illustrating the complexity of the relationship between hyperacuity and resolution functions.

Adolescent↗

PubMed1995

Movement hyperacuity threshold deficit in juvenile onset diabetes mellitus.

Oscillatory movement displacement thresholds from a group of 18 normal children (mean age of 9.2 +/- 3.6 years) were compared with those obtained from a group of 26 age-matched children (mean age of 9.9 +/- 2.9 years) having insulin-dependent diabetes mellitus. Disease durations ranged from 6 months to 12 years, although no ophthalmoscopic evidence of retinopathy was found in any subject. Up to about 8 years of age there is no significant difference in the performance of diabetics and controls (t = 1.00, p = n.s.), oscillatory movement displacement thresholds correlating with age in both groups (r= -0.59, p < 0.02). Over about 8 years of age oscillatory movement displacement thresholds no longer improve and the two groups perform significantly differently, thresholds being degraded in the insulin-dependent diabetes mellitus group compared to normals (t = 5.25, p <<0.0001). It is suggested that the measurement of oscillatory movement displacement thresholds in children with insulin-dependent diabetes mellitus can reveal its effects in the absence of retinopathy.

Adolescent↗