Ophthalmic changes from age of 10 to 18 years. A longitudinal study of sequels to low birth weight. IV. Ultrasound oculometry of vitreous and axial length.

The present report on vitreous and axial length completes an analysis of changes in eye size during adolescence. The sample is divided into 70 with low birth weight (less than 2000 g) and 67 full-term controls (FT). 1) Contrary to classical statements regarding early arrest of eye growth, a basic 'pubertal' axial growth of about 0.4-0.5 mm is found in refractively static eyes. Eyes with progressive myopia elongate even more, due mainly to vitreous elongation. 2) The previously reported 10-year LBW ocular size deficit remains an adult feature, even in seemingly normal eyes. There is a parallel permanent lack of catching-up also regarding height, head circumference, and some other anthropometric parameters. 3) Two classical rules of thumb are discussed: a) 1 mm axial length change coincides with 3 D refractive change, and b) that of 24 mm as the emmetropic eye length. Although tenacious, bot statements have to be modified--according to biological variation and the weak correlation between most refractive parameters.