Ultrasonographic measurement of ocular refractive components in eyes with various refractive states

Ultrasonographic measurements were done by contact technique in 231 eyes of 118 patients with the ages varying between 20 and 40. Patients were classified in to 5 groups according to their refraction states; high myopia, myopia, emmetropia, hypermetropia and high hypermetropia. Parameters like axial eye length, anterior chamber depth, antero-posterior lens diameter and vitreous length were measured with autobiometric method using "Teknar Ophthasonic A-Scan/B-Scan III Unit". In all groups, a significant positive correlation between vitreous length and axial length was determined (p<0.001). In emmetropic eyes, there was a significant positive correlation between anterior chamber depth and axial length (p<0.001). There was, generally, a negative correlation both in between lens thickness and axial length, and in between lens thickness and anterior chamber depth. In myopic eyes, statistically significant positive correlation was determined between refractive state and axial length (p<0.001). While the average axial length in emmetropic eyes was determined as 23.19 mm. It was seen that there was a wide variation in axial length (4.35 mm). When our results were evaluated together with literature, we came to a conclusion that the most important parameter determining the refraction is axial eye length and the vitreous length that is the component of axial length.