Cataract Surgery After Refractive Surgery

Ravi H. Patel, MD; Carol L. Karp, MD; Sonia H. Yoo, MD; Guillermo Amescua, MD; Anat Galor, MD, MSPH

Disclosures

Int Ophthalmol Clin. 2016;56(2):171-182. 

In This Article

Background

To determine optimal IOL power, several preoperative measurements are needed. These include at a minimum measuring axial length and corneal power, and when using newer generation formulas, anterior chamber depth and horizontal corneal diameter are also considered. In most cases, these measurements can be obtained using optical coherence biometry and the values placed into regression formulas using optimized lens A constants to determine IOL power. In naive corneas, traditional formulas such as the Holiday 1 and SRK/T do an excellent job in predicting postsurgical emmetropia. In most studies, a refractive error within 0.5D of emmetropia was achieved in 70% of individuals.[1] In postrefractive eyes, however, these formulas are known to be inaccurate as both measurements of corneal curvature and regression formulas have sources that contribute to error in patients with a history of prior refractive surgery. In general, traditional IOL formulas usually result in a hyperopic surprise when applied to patient's status postmyopic correction and in a myopic surprise when applied to patient's status posthyperopic correction.[2–5]

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