Cataract & IOL Care After LASIK
by David A. Wallace MD
Both LASIK and lens-based care (including cataract surgery) are excellent methods of vision correction. Typically, LASIK is quite popular among people in the age range from about 20 - 50 years. By contrast, cataract and lens replacement care is most common in the over-55 age range. It will become increasingly common, therefore, to encounter the situation wherein someone has had prior LASIK, and years later finds it necessary or beneficial to investigate having cataract or lens replacement treatment.
Prior to the evolution of LASIK, cataract and lens implant surgery (using an intra-ocular lens or "IOL") was by far the most common operation performed by eye doctors worldwide. Currently in the US, approximately 1.8 million cataract procedures are performed annually. In 2009, in our practice at LA Sight, roughly 5% of cataract care patients had previously had LASIK. As the generation of baby-boomers matures, we expect this number to rise into the range of 30 - 35%.
While the cataract surgery procedure is identical whether someone has had LASIK previously or not, the calculation of the exact prescription (or "IOL power") is more challenging if LASIK (or any vision-correcting surgical procedure) has previously been performed.
Dr. Wallace and the team at LA Sight are experts in both lens implant care and LASIK. Additionally, we have particular expertise in calculating optimal IOL power in eyes that have had previous laser vision correction surgery. In this situation, certain subtle adjustments in IOL power (i.e. the prescription strength of the lens implant) are warranted, and need to be factored in before-hand to assure best unaided vision afterwards.
When planning for lens replacement or cataract care, it is always necessary to implant an IOL to restore excellent unaided vision. Certain special measurements are performed prior to cataract care (called "biometry"), to assist in calculating the correct IOL power to be used at time of surgery. Biometry typically involves measurement of certain anatomic parameters of the eyes including (a) Corneal radius of curvature (keratometry), (b) Axial Length (ocular diameter from cornea to retina along the visual axis), (c) Anterior Chamber Depth (distance from cornea to front of natural lens), Lens Thickness, and Horizontal Corneal Diameter ("white-to-white"). Previous LASIK changes corneal curvature and asphericity, so these must be additionally accounted for.
When possible, it is quite helpful to know the amount of any previous prescription treated by LASIK. We will make efforts to contact surgeons and laser centers to determine this if it is not already known.
Even if all the ocular dimensions are precisely measured, and the amount of prior LASIK treatment is known, there can still be uncertainties that lead to imperfect predictions of IOL power. In these cases it is usually relatively easy to "fine-tune" the visual and optical result with a small amount of additional LASIK. One of the true advantages we have over the vast majority of other "cataract specialist" offices in LA is that we have an excellent laser on-site, and can do any needed touch-up work in our own office, rather than using an outside facility (typically at greater cost).