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J Cataract Refract Surg. 2015 Apr;41(4):785-9. doi: 10.1016/j.jcrs.2014.07.035.

Influence of corneal asphericity on the refractive outcome of intraocular lens implantation in cataract surgery.

Author information

1
From the Fondazione G.B. Bietti IRCCS (Savini), Rome, Studio Oculistico d'Azeglio (Barboni), Bologna, and the Scientific Institute San Raffaele (Barboni), Milan, Italy; the Stein Eye Institute (Hoffer), University of California, and St. Mary's Eye Center (Hoffer), Santa Monica, California, USA. Electronic address: giacomo.savini@alice.it.
2
From the Fondazione G.B. Bietti IRCCS (Savini), Rome, Studio Oculistico d'Azeglio (Barboni), Bologna, and the Scientific Institute San Raffaele (Barboni), Milan, Italy; the Stein Eye Institute (Hoffer), University of California, and St. Mary's Eye Center (Hoffer), Santa Monica, California, USA.

Abstract

PURPOSE:

To evaluate the possible influence of anterior corneal surface asphericity on the refractive outcomes in eyes having intraocular lens (IOL) implantation after cataract surgery.

SETTING:

Fondazione G.B. Bietti IRCCS, Rome, Italy.

DESIGN:

Retrospective comparative case series.

METHODS:

Intraocular lens power was calculated using the Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. Asphericity (Q-value) was measured at 8.0 mm with a Placido-disk corneal topographer (Keratron), a rotating Scheimpflug camera (Pentacam), and a rotating Scheimpflug camera combined with Placido-disk corneal topography (Sirius). The relationship between the error in refraction prediction (ie, difference between expected refraction and refraction measured 1 month after surgery) and the Q-value was assessed by linear regression.

RESULTS:

The same IOL model (Acrysof SA60AT) was implanted in 115 eyes of 115 consecutive patients. Regression analysis showed a statistically significant relationship between the error in refraction prediction and the Q-value with all formulas and all devices. In all cases, a more negative Q-value (prolate cornea) was associated with a myopic outcome, whereas a more positive Q-value (oblate cornea) was associated with a hyperopic outcome. The highest coefficient of determination was detected between the Hoffer Q formula and the Placido-disk corneal topographer (R(2) = 0.2630), for which the error in refraction prediction (y) was related to the Q-value (x) according to the formula y = -0.2641 + 1.4589 × x.

CONCLUSION:

Corneal asphericity influences the refractive outcomes of IOL implantation and should be taken into consideration when using third-generation IOL power formulas.

FINANCIAL DISCLOSURE:

Dr. Hoffer receives book royalties from Slack, Inc., Thorofare, New Jersey, and formula royalties from all manufacturers using the Hoffer Q formula. No other author has a financial or proprietary interest in any material or method mentioned.

PMID:
25840302
DOI:
10.1016/j.jcrs.2014.07.035
[Indexed for MEDLINE]

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