Abstract
Purpose:
To explore the effect of oral administration of nicotinic acid on eye growth of normal and myopic chicks. The nicotinic acid is the normal drug used in human to raising the HDL in blood. The Apolipoprotein A1 is the potential in protect myopic eye growth in previous studies.
Methods:
White Leghorn chicks aged at 4 days (n = 48 in total) were randomly allocated into 4 groups. Chicks in group A and B were orally administered a single dose of nicotinic acid daily (150mg/ml, 1ml per chick) while the chicks in group C and D were received saline orally as control (1ml per chick). The oral administration last for 11 consecutive days. After 7 days of oral administration, -10D lenses were attached to both eyes of the chicks in group A and C while the chicks in group B and D worn plano lenses for 4 days. The refractive errors and ocular dimension components were examined using streak retinoscopy and high resolution A-scan ultrasonography before and after 11 days of the oral administration respectively. The changes of refractive errors and vitreous chamber depth between 1 days and 11 days of oral administration were gained. T-test was used to analysis the difference.
Results:
After 4 days of lens wear, chicks with -10D lenses became significantly more myopic than the chicks with plano lenses (A and B group: P= 0.0274; C and D group: P= 0.0013; t-test). In the groups with -10D lenses (group A and C), the changes in vitreous chamber depth (VCD) in chicks treated with nicotinic acid (mean ± SEM; 0.568 ± 0.146mm) were significantly less than that of the saline-treated chicks (0.778 ± 0.197 mm, p = 0.007, t-test). The change in refractive errors in chicks treated with nicotinic acid (mean ± SEM; -8.35 ± 1.11D) were significantly less than that of the saline-treated chicks (-10.81± 0.75D, p = 2.20E-06, t-test). There was no significant difference in VCD between the groups wearing plano lenses (group B: nicotinic acid vs. group D: saline; 0.398 ± 0.202mm, vs. 0.514± 0.151mm, p = 0.125, t-test). But there was significant difference in refractive errors between the groups wearing plano lenses (group B: nicotinic acid vs. group D: saline; -3.25 ± 0.30D, vs. -4.54 ± 0.35D, p = 2.20E-09, t-test).
Conclusions:
The nicotinic acid intake could retard the elongation of VCD in lens-induced myopic chicks. Its effect on the normal ocular growth is however not apparent.