Understanding refraction and accommodation through 'retinal imaging' aberrometry - A case report

Purpose: A new form of aberrometry based on Tscherning optics has been prop osed that captures the refraction and high-order aberrations of the eye wit h and without accommodation. Design: Experimental clinical optics study, Method: A green neodymium:yttrium-aluminum-garnet laser grid pattern is pro jected into the eye and viewed on the retina through a narrow, collimated a perture of 1 mm, The resulting aberrated pattern is photographically record ed in a normal eye in the unaccommodated and accommodated state through a p harmacologically dilated pupil without cycloplegia, Main Outcome Measures: Detection of pupil-dependent refraction and high-ord er optical aberration with and without accommodation. Results: Subtle pupil-dependent errors in refraction and high-order aberrat ions (spherical aberrations and coma) are demonstrated in the unaccommodate d normal eye. Accommodation reveals slightly more spherical power through t he central 3-mm zone than through a 6.5-mm pupil without significant increa se in aberration, Conclusions: Tscherning aberrometry based on 'retinal imaging' is useful in defining the refraction and optical aberrations in a normal eye. Accommoda tion increases spherical refractive power with only small aberration change s, including negative asphericity. (C) 2001 by the American Academy of Opht halmology.