2020–2021 BCSC Basic and Clinical Science Course™
3 Clinical Optics
Chapter 6: Intraocular Lenses
Intraocular Lens Power in Corneal Transplant Eyes
It is very difficult to predict the ultimate power of the cornea after the eye has undergone penetrating keratoplasty. Thus, in 1987 Hoffer recommended that the surgeon wait for the corneal transplant to heal completely before implanting an IOL. The current safety of intraocular surgery allows for such a double-procedure approach in all but the rarest cases. Geggel has proven the validity of this approach by showing that posttransplant eyes have better uncorrected visual acuity (68% with 20/40 or better) and that the range of IOL power error decreases from 10 D to 5 D (95% within ±2.00 D).
If simultaneous IOL implantation and corneal transplant are necessary, surgeons may use either the K reading of the fellow eye or the average postoperative K value of a previous series of transplants, but these approaches are fraught with error. When there is corneal scarring in an eye but no need for a corneal graft, it might be best to use the corneal power of the other eye or even a power that is commensurate with the eye’s AL and refractive error.
Flowers CW, McLeod SD, McDonnell PJ, Irvine JA, Smith RE. Evaluation of intraocular lens power calculation formulas in the triple procedure. J Cataract Refract Surg. 1996;22(1): 116–122.
De Bernardo M, Capasso L, Caliendo L, Paolercio F, Rosa N. IOL power calculation after corneal refractive surgery. Biomed Res Int. 2014;33(6):e2.
Geggel HS. Intraocular lens implantation after penetrating keratoplasty. Improved unaided visual acuity, astigmatism, and safety in patients with combined corneal disease and cataract. Ophthalmology. 1990;97(11):1460–1467.
Hoffer KJ. Triple procedure for intraocular lens exchange. Arch Ophthalmol. 1987;105(5): 609–610.
Excerpted from BCSC 2020-2021 series : Section 3 - Clinical Optics. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.