Understanding refraction and accommodation through "retinal imaging" aberrometry: a case report.

PURPOSE

A new form of aberrometry based on Tscherning optics has been proposed that captures the refraction and high-order aberrations of the eye with and without accommodation.

DESIGN

Experimental clinical optics study.

METHOD

A green neodymium:yttrium-aluminum-garnet laser grid pattern is projected into the eye and viewed on the retina through a narrow, collimated aperture of 1 mm. The resulting aberrated pattern is photographically recorded in a normal eye in the unaccommodated and accommodated state through a pharmacologically dilated pupil without cycloplegia.

MAIN OUTCOME MEASURES

Detection of pupil-dependent refraction and high-order optical aberration with and without accommodation.

RESULTS

Subtle pupil-dependent errors in refraction and high-order aberrations (spherical aberrations and coma) are demonstrated in the unaccommodated normal eye. Accommodation reveals slightly more spherical power through the central 3-mm zone than through a 6.5-mm pupil without significant increase in aberration.

CONCLUSIONS

Tscherning aberrometry based on 'retinal imaging' is useful in defining the refraction and optical aberrations in a normal eye. Accommodation increases spherical refractive power with only small aberration changes, including negative asphericity.