Wydanie 2/2011
str. 34

Zaburzenie konwergencji akomodacyjnej w sytuacji, gdy bodziec akomodacyjny jest jednobarwny

Accommodative Convergence Disturbances Using Monochromatic Accommodative Stimulus

Malwina Lewandowska-Soboń

Zespół Optyki Widzenia Instytutu Fizyki Politechniki Wrocławskiej
Kierownik: prof. dr hab. Henryk Kasprzak

Summary: Purpose: It is well known that the precision of convergence mechanism has essential meaning for good binocular vision, and its accuracy is even more important than correct accommodation. Chromatic aberration is a source of information on the desired direction of focusing and thus is an essential factor for proper accommodation. Both: accommodation and convergence is caused by the same stimuli. The aim of this paper is to measure the AC/A ratio in the situation when chromatic aberration cannot be used for accommodation control.
Material and Methods: The AC/A ratio was measured for: white (LED-diode), blue (maximum transmittance 440 nm), green (maximum transmittance 550 nm) and red (maximum transmittance 640 nm) light. 22 individuals in the age ranging from 22 to 30 (average 24.1 years, standard deviation 0.6 year) were measured. Most of them (45%) did not have any refractive error, 35% of the patients were myopic and the remaining 20% of patients had a small (from 0.25 D to + 0.75 D) hypermetropia.
Results: The repeatability of the AC/A ratio in white light was highest and the dependency of accommodative convergence on accommodation was practically linear (correlation coefficient R2=0.945). If the stimulus was one-coloured the blur of AC/A ratio was substantially greater and the correlation between accommodative convergence and accommodation was much smaller.
Conclusions: Lack of chromatic blur causes disturbance of accommodation mechanism and in consequence diminishing of accommodative convergence accuracy. The way in which chromatic aberration affects the AC/A is individual and can not specify any rules here. In everyday life, small irregularities are compensated, however, greater deviation may already be a serious problem.

Słowa kluczowe: konwergencja akomodacyjna, akomodacja, aberracja chromatyczna.

Keywords: accommodative convergence, accommodation, chromatic aberration.