Some patients continue to have residual short or long sight after cataract surgery. This can happen for a number of reasons including wrong lens insertion, however the commonest cause is the simple fact that lens power calculations are based on theoretical predictive formulae that use normal population data.
Any normal population follows a bell curve distribution and hence there are always potential outliers within the prediction range. These outliers are uncommon but when applied to cataract surgery can mean that the predicted lens powers is less accurate, leaving the patient with long or short sight.
If a person has been left with some residual glasses prescription after cataract surgery there are a number of options to correct this. The simplest is to wear the appropriate pair of glasses! However, if you don’t want to wear glasses the options available are lens exchange or an add on lens, both of which involve further surgery inside the eye, or laser eye surgery. Laser surgery may in fact be the safest option in this situation. A recent study is shown below.
‘LASIK was found to be the most accurate technique for correcting residual refractive error after cataract surgery; however, lens-based procedures are preferred in cases with severe ametropia, corneal abnormalities or an unavailable excimer laser platform, according to a study.
Sixty-five eyes of 54 patients with unacceptable final refractive error results after phacoemulsification were included in the retrospective, multicenter study.
Eyes were categorized into three groups: 17 eyes had an IOL exchange, 20 eyes had a piggyback lens implanted, and 28 eyes had LASIK.
No differences were found in spherical equivalent, sphere or cylinder between the IOL exchange and piggyback lens groups.
Compared with the IOL exchange group, the LASIK group had a statistically significant reduction in refractive cylinder and spherical equivalent (P = .001 and P < .001, respectively). The LASIK group had a statistically significant reduction in refractive cylinder when compared with the piggyback lens group (P = .002).
The median efficacy values were statistically significant between the IOL exchange and LASIK groups (P = .004) and the piggyback lens and LASIK groups (P = .003).
Regarding predictability, 62.5% of eyes in the IOL exchange group, 85% of eyes in the piggyback lens group and 100% of eyes in the LASIK group were within ±1 D of final spherical equivalent. The differences were significant (P = .003).
Disclosure: The study authors have no relevant financial disclosures.’