Ocular Dimensions (ocular + dimension)

Distribution by Scientific Domains

Selected Abstracts

Effects of hyperglycaemia on ocular development in rabbit: refraction and biometric changes

Peter Herse
Abstract Aim:, To determine the effect of acute and chronic hyperglycaemia on the refraction and development of the rabbit eye. Methods:, Ocular dimensions of five alloxan-induced hyperglycaemic and six control rabbits were measured over 9 weeks using A scan biometry. Refraction was measured using retinoscopy. The animals were 10 weeks of age at the start of the experiment. Results:, The acute onset of hyperglycaemia was associated with a fast and stable 2 D hyperopic shift in refraction. Lens thickness increased during the first 2 weeks of hyperglycaemia, returned to near normal thickness after 3,5 weeks of hyperglycaemia and then decreased in thickness in the last 4 weeks of the study. The hyperopic refraction remained unchanged during changes in lens thickness. Nine weeks of hyperglycaemia was associated with a 25% reduction in the growth of both the globe and the lens and a 17% decrease in body mass compared with the controls. Conclusion:, The hyperopic refraction change of acute hyperglycaemia is likely to be because of a change in the refractive index of the cortical fibres of the lens and is the probable source of the fluctuating refraction seen in diabetic patients. Chronic hyperglycaemia reduced the axial development of the eye and is the probable source of the chronic hyperopic refraction seen in children with Type I diabetes. [source]

Relationships between ophthalmological and neuropaediatric findings in children adopted from Eastern Europe

Marita Andersson Grönlund
Abstract. Purpose:, This study aimed to evaluate and relate visual function, ocular dimensions and neuropaediatric findings in adoptees from Eastern Europe. Methods:, We studied 72 of 99 children, born during 1990,95 and adopted from Eastern Europe to western Sweden during 1993,97. The children (mean age 7.5 years, range 4.8,10.5 years; 41 boys, 31 girls) were examined after a mean period of 5 years post-adoption by a multidisciplinary team. Correlations between ophthalmological findings and neuropaediatric data were analysed. Results:, Bivariate and regression analyses indicate a significant positive correlation between visual acuity (VA) and perceptual organization (p < 0.001), as well as between strabismus and verbal comprehension (p < 0.02). Fetal alcohol syndrome (FAS) was correlated with low VA (p < 0.02), subnormal stereovision (p < 0.009) and small optic discs (p < 0.02). Small head circumference was related to low VA (p < 0.015) and small optic discs (p < 0.03). Furthermore, small optic discs were related to low birthweight (p < 0.005) and preterm birth (p < 0.01). Large optic cups were correlated with poorer perceptual organization (p < 0.02). Conclusions:, In this group of adoptees from Eastern Europe, ophthalmological findings were correlated to neuropaediatric findings, especially those arising from prenatal adverse events resulting in growth deficiency and central nervous system damage. Therefore, it is important and valuable with an ophthalmological examination in children adopted from Eastern Europe. [source]

Relationships between ocular dimensions and adult stature among participants in the Reykjavik Eye Study

Thor Eysteinsson
Abstract. Purpose:,To examine the relationships between adult stature, age and ocular dimensions in a large homogenous, white population. Methods:,We used the national population census for Reykjavik to select a random sample of adults aged 50 years or older. A total of 846 persons were examined. Scheimpflug images were used to measure anterior chamber depth. Ultrasound was used to measure axial length, lens thickness and vitreous chamber depth. An autorefracto-keratometer was used to measure autorefractive and keratometric values, including the radius of the corneal curvature. Stereo fundus photographs were taken of the optic disc and measurements of the disc diameters were made using computer software. Results:,Height correlated positively with axial length in the multivariate model (B = 0.020, 95% CI 0.006,0.034, p < 0.01). Both age and height showed significant correlations with vitreous chamber depth, where the correlation with age was negative (B = , 0.016, 95% CI , 0.006 to , 0.025, p < 0.005) and the correlation with height was positive (B = 0.019, 95% CI 0.005,0.034, p < 0.01). Height also showed a positive correlation with the radius of the corneal curvature (B = 0.008, 95% CI 0.004,0.011, p < 0.001). Anterior chamber depth had a negative correlation with age (B = , 0.013, 95% CI , 0.010 to , 0.016, p < 0.001), whereas lens thickness had a significant positive correlation with age (B = 0.019, 95% CI 0.016,0.023, p < 0.001). We found a significant negative correlation between axial length and refraction/spherical equivalent (r = , 0.595, p < 0.0001). Discussion:,Our results indicate that there is a significant relationship between height and several ocular dimensions in this adult population and confirms a negative correlation between axial length and refraction. [source]