[Mechanism of accommodation of human eye--some new aspects].
BACKGROUND
The basics of the model of accommodation were described by Hermann von Helmholtz 150 years ago and are accepted until today.


METHODS
Twenty-five healthy young phakic test persons (age range 14 to 28 years) were examined using the IOL Master (Carl Zeiss Jena GmbH), slit lamp photography (Scheimpflug camera EAS 1000, Nidek) and pupillography (AMTech GmbH). Measurements were taken of disaccommodated and accommodated eyes.


RESULTS
The mesopic and photopic pupil size are statistically significant (p < 0.05) smaller in accommodated eyes than in disaccommodated. Also, a significantly shorter reaction time of the light-induced pupil reaction with accommodation could be shown compared to disaccommodation. The central vertical and horizontal radii of curvature of the cornea increased with accommodation. This is likewise a decrease of the central anterior corneal curvature by near fixation. Due to the axial lens thickening, the anterior chamber angle and the anterior chamber depth decreased. Consequently, a decrease of the lens transparence resulted with accommodation.


CONCLUSIONS
As a result of our measurements the existing model of accommodation, developed by Hermann von Helmholtz 150 years ago, can be modified.
Müller
M
M
Augenklinik des Universitätsklinikums, Jena. melanie.mueller@med.uni-jena.de
Strobel
J
J
D000065:Accommodation, Ocular; D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D011680:Pupil / Q000502:physiology*