VARIATION OF ASTIGMATISM WITH ACCOMMODATION AND ITS RELATIONSHIP WITH DARK FOCUS

Abstract— The refraction of 122 eyes was measured for five distances of fixation with an objective Canon Auto Refractor. The cylindrical component was found to vary, but by a small amount. We found no evidence of a deliberate reduction in astigmatism with accommodation, in accord with other studies. The axis was also found to vary by at least 5° in about half of the subjects tested, which is also in good accord with other investigations. The dark focus of 31 eyes was not found to correlate with a minimum astigmatic distance, since this only occurred in II out of the 31 eyes. For these 11 eyes, the correlation of dark focus and the dioptric distance where astigmatism was minimum was equal to + 0.54. It implied that for those eyes (about one‐third of all types) there was a tendency to yield the best optical quality at the dark focus.

[1]  P. Denieul,et al.  Effects of stimulus vergence on mean accommodation response, microfluctuations of accommodation and optical quality of the human eye , 1982, Vision Research.

[2]  Erik Ingelstam,et al.  LOW‐LUMINANCE MYOPIA AS MEASURED WITH A LASER OPTOMETER , 1981 .

[3]  R. J. Maddock,et al.  Accommodation responses and refractive error. , 1981, Investigative ophthalmology & visual science.

[4]  U. Halldén,et al.  ASTIGMATISM OF THE LENS BY ASYMMETRIC CONTRACTION OF THE CILIARY MUSCLE , 1974, Acta ophthalmologica.

[5]  R. Mandell,et al.  STABILITY OF THE CORNEAL CONTOUR* , 1968, American journal of optometry and archives of American Academy of Optometry.

[6]  S. Kabe.  [Supplementary research on the changes caused by accommodation in the refractive elements of the eyes. 3. Changes in astigmatism of the crystalline lens associated with accommodation]. , 1968, Nippon Ganka Gakkai zasshi.

[7]  R. Weale,et al.  Changes in corneal curvature following ocular convergence. , 1965, Vision research.

[8]  R. Bannon.  A study of astigmatism at the near point with special reference to astigmatic accommodation. , 1946, American journal of optometry and archives of American Academy of Optometry.

[9]  M. Brzeziński.  Review: Astigmatic Accommodation (Sectional Accommodation) – a form of Dynamic Astigmatism , 1982 .

[10]  R. J. Fletcher.  Astigmatic accommodation. , 1951, The British journal of physiological optics.

[11]  R. Bannon,et al.  Accommodative astigmatism. , 1947, American journal of ophthalmology.