The effect of vision on craniocervical posture and its relation to craniofacial and dentoalveolar morphology.

Vision is one of the most important factors involved in the control of head posture. Therefore, head posture is different in blind persons. The purpose of the present study was to determine the posture of the head and cervical column in relation to the true vertical and horizontal and to record craniofacial and dentoalveolar morphology in a group of blind subjects. The sample consisted of 20 blind subjects, who had been totally blind since birth, and 20 normal-sighted persons. The analysis of head posture showed that the intraindividual and interindividual variation in the craniovertical angles was larger in the blind group than it was in the control group, but the variation in the craniocervical angles was similar in both groups. The different head posture in the blind group was produced by forward-downward tilting of the head and neck in combination with an unchanged craniocervical angulation. In the blind group, the difference in head posture affected the mandibular position so that the craniofacial and dentoalveolar morphology showed a difference: an increase in the mandibular angle and in vertical jaw relationships and at the same time a decrease in inclination of the mandibular incisors.