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


CONCLUSIONS
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.
Herse
Peter
P
School of Optometry and Vision Science, University of New South Wales, Sydney, NSW 2053, Australia. p.herse@unsw.edu.au
D000208:Acute Disease; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002908:Chronic Disease; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D005123:Eye / Q000473:pathology / Q000503:physiopathology*; D007908:Lens, Crystalline / Q000473:pathology / Q000503:physiopathology; D008297:Male; D011817:Rabbits; D012029:Refraction, Ocular; D013997:Time Factors
D001786:Blood Glucose