Simultaneous vs. bilateral LASIK.

Abstract

In their article, Chiang and Hersh1Chiang P.K. Hersh P.S. Comparing predictability between eyes after bilateral laser in situ keratomileusis a theoretical analysis of simultaneous versus sequential procedures.Ophthalmology. 1999; 106: 1684-1691Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar concluded that it is theoretically advantageous to perform sequential bilateral laser in situ keratomileusis (LASIK) as opposed to simultaneous bilateral LASIK. We have several concerns with regard to this conclusion. First, in our study of 2142 consecutive simultaneous and sequential bilateral myopic LASIK cases, we found no statistically significant difference in 3- to 6-month postoperative refractive or visual outcomes, including spherical equivalent, uncorrected acuity, best-corrected visual acuity, and retreatment rates.2Gimbel HV, van Westenbrugge JA, Anderson Penno EE, et al. Simultaneous bilateral laser in situ keratomileusis: safety and efficacy. Ophthalmology 1999;106:1461–7; discussion 1467–8.Google Scholar In fact, the retreatment rate in sequential eyes was slightly higher, although not statistically significantly higher than in simultaneous bilateral eyes. Second, other studies, including a prospective study by Waring et al3Waring III, G.O. Carr J.D. Stulting R.D. et al.Prospective randomized comparison of simultaneous and sequential bilateral laser in situ keratomileusis for the correction of myopia.Ophthalmology. 1999; 106: 732-738Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar, 4Waring III, G.O. Carr J.D. Stulting R.D. Thompson K.P. Prospective, randomized comparison of simultaneous and sequential bilateral LASIK for the correction of myopia.Trans Am Ophthalmol Soc. 1997; 95: 271-284PubMed Google Scholar involving 714 eyes, have also concluded that simultaneous bilateral surgery was equally safe and effective as compared with sequential bilateral surgery. (Vicary D, et al. American Society of Cataract and Refractive Surgery, Symposium on Cataract, IOL and Refractive Surgery, 1998;34. Hardten DR, et al. American Society of Cataract and Refractive Surgery, Symposium on Cataract, IOL and Refractive Surgery, 1998;34.) In addition, only sequential surgeries in 196 eyes were studied by Chiang and Hersh,1Chiang P.K. Hersh P.S. Comparing predictability between eyes after bilateral laser in situ keratomileusis a theoretical analysis of simultaneous versus sequential procedures.Ophthalmology. 1999; 106: 1684-1691Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar compared with the larger studies cited above, which included both simultaneous and sequential bilateral surgeries.2Gimbel HV, van Westenbrugge JA, Anderson Penno EE, et al. Simultaneous bilateral laser in situ keratomileusis: safety and efficacy. Ophthalmology 1999;106:1461–7; discussion 1467–8.Google Scholar, 3Waring III, G.O. Carr J.D. Stulting R.D. et al.Prospective randomized comparison of simultaneous and sequential bilateral laser in situ keratomileusis for the correction of myopia.Ophthalmology. 1999; 106: 732-738Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar, 4Waring III, G.O. Carr J.D. Stulting R.D. Thompson K.P. Prospective, randomized comparison of simultaneous and sequential bilateral LASIK for the correction of myopia.Trans Am Ophthalmol Soc. 1997; 95: 271-284PubMed Google Scholar (Vicary D, et al. American Society of Cataract and Refractive Surgery, Symposium on Cataract, IOL and Refractive Surgery, 1998;34. Hardten DR, et al. American Society of Cataract and Refractive Surgery, Symposium on Cataract, IOL and Refractive Surgery, 1998;34.) Finally, Chiang and Hersh1Chiang P.K. Hersh P.S. Comparing predictability between eyes after bilateral laser in situ keratomileusis a theoretical analysis of simultaneous versus sequential procedures.Ophthalmology. 1999; 106: 1684-1691Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar found no statistically significant differences in measured postoperative manifest refraction or variance from emmetropia between the first and second eyes, nor was there any mention of retreatment rates for first or second eyes. The authors admit that the “improved outcomes of sequential treatments shown are theoretical and are not clinically proved.” Although it continues to be important to examine both theoretical results (or outcomes) as well as data from clinical trials, caution is advisable when drawing conclusions from theoretical outcomes. This is especially true when the weight of clinical data, including the data from the Chiang and Hersh study, do not support the theoretical conclusion. Author’s replyOphthalmologyVol. 108Issue 3Preview Full-Text PDF