Refracting surface which is free from spherical aberration

The Q value of a young adult crystalline lens is As the lens ages, the Q value changes, and after age 40 is 0. With a perfect single refracting surface such as an ellipse, keratometry and Q value could be used to calculate the spherical aberration of that surface. For a corneal Q value of The average measured spherical aberration of the cornea is 0.

Common aspheric IOLs correct the average theoretical corneal spherical aberration, the average measured corneal spherical aberration, or do not influence it. Aspheric lenses must be decentered more than 0. Current strategies involve targeting up to George H. Beiko states that he is a consultant to Abbott Medical Optics Inc. He may be reached at e-mail: george. Search for:. CRST Europe.

End of Issue. Validation of the estimation of corneal aberrations from videokeratography in keratoconus. J Refract Surg. Corneal aberrations before and after small-incision cataract surgery. Invest Ophthalmol Vis Sci. Distribution of the corneal spherical aberration in a comprehensive ophthalmology practice, and can keratometry be predictive of the value of the corneal spherical aberration?

J Cataract Refract Surg. Pesudovs K. Meta-analysis of studies comparing wavefront aberration and visual performance of spherical and aspheric intraocular lenses. Then a cover is placed over the outer edges of the large demonstration mirror. The result is that the image suddenly becomes more clear and focused. When the problematic portion of the mirror is covered so that it can no longer focus or mis-focus light, the image appears more focused.

Spherical aberration is most commonly corrected by use of a mirror with a different shape. Usually, a parabolic mirror is substituted for a spherical mirror. The outer edges of a parabolic mirror have a significantly different shape than that of a spherical mirror.

Parabolic mirrors create sharp, clear images that lack the blurriness which is common to those images produced by spherical mirrors. Physics Tutorial. My Cart Subscription Selection. Cited By You do not have subscription access to this journal. Figures 4 You do not have subscription access to this journal. Equations 16 You do not have subscription access to this journal. Metrics You do not have subscription access to this journal. Journal Home. Issues in Progress.

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