Reply

Abstract

We appreciate Dr Kim's point regarding our recent publication.1Shorstein N.H. Liu L. Waxman M.D. Herrinton L.J. Comparative effectiveness of three prophylactic strategies to prevent clinical macular edema after phacoemulsification surgery.Ophthalmology. 2015; 122: 2450-2456Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar Although the addition of a nonsteroidal anti-inflammatory drug (NSAID) to topical prednisolone acetate (PA) decreased the incidence of visually significant post-phacoemulsification macular edema (i.e., with visual acuity of ≤20/40 at diagnosis), the overall rate was low. The clinical significance of this rate, however, is still incompletely understood. The effect of macular edema on visual acuity after recovery from phacoemulsification has not been examined in a controlled study with adequate follow-up, and our study did not have adequate resources to enable processing of late visual outcomes. Thus, the question of whether prophylactic NSAID improves late visual outcomes remains unresolved. However, Hunter et al2Hunter A.A. Modjtahedi S.P. Long K. et al.Improving visual outcomes by preserving outer retina morphology in eyes with resolved pseudophakic cystoid macular edema.J Cataract Refract Surg. 2014; 40: 626-631Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar demonstrated ultrastructural changes in photoreceptors using ultra–high-resolution optical coherence tomography in patients' eyes with subnormal vision after phacoemulsification. Macular edema may have more of a permanent, long-lasting effect on vision than previously realized and merits further study. Kim also suggests that NSAID plus PA in essence doubles the dose of a single-mechanism agent.3Kim S.J. Schoenberger S.D. Thorne J.E. et al.Topical nonsteroidal anti-inflammatory drugs and cataract surgery: a report by the American Academy of Ophthalmology.Ophthalmology. 2015; 122: 2159-2168Abstract Full Text Full Text PDF PubMed Scopus (115) Google Scholar This depends on how the drops were instilled by the patient. If both drops were instilled within a few seconds of each other, assuming no synergistic effect, then this is closer to a single instillation of 1 agent, given the small carrying volume of the eye surface.4Shell J.W. Pharmacokinetics of topically applied ophthalmic drugs.Surv Ophthalmol. 1982; 26: 207-218Abstract Full Text PDF PubMed Scopus (272) Google Scholar However, if the drops were instilled some minutes apart, substantial absorption of drug from the first drop would most likely occur before instillation of the second drug, allowing for an increase in overall drug concentration in the anterior chamber, and thus potentially doubling the dose of anti-inflammatory agent. Studies have shown that patients have a poor track record for separating drops and instilling them correctly,5An J.A. Kasner O. Samek D.A. Lévesque V. Evaluation of eyedrop administration by inexperienced patients after cataract surgery.J Cataract Refract Surg. 2014; 40: 1857-1861Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar and we question whether “double dosing” can explain the 55% decrease in macular edema risk that we observed. The question of prophylactic agent and the association with late, postoperative visual acuity requires further study. In addition, subgroup analysis examining ocular comorbidity and race is needed to evaluate whether prophylaxis is especially beneficial in these patients, and to examine the risks of NSAID. With an annual rate of 3 million cataract surgeries performed each year, and the widespread use of prophylactic NSAIDs in the United States, these questions have profound public health significance. Re: Shorstein et al.: Comparative effectiveness of three prophylactic strategies to prevent clinical macular edema after phacoemulsification surgery (Ophthalmology 2015;122:2450-6)OphthalmologyVol. 123Issue 9PreviewI read with great interest the recent article by Shorstein et al1 comparing the effectiveness of different strategies to prevent clinically important macular edema after cataract surgery. Despite the inherent limitations of retrospective claims data analysis and potential for bias (which the authors acknowledge), there are several strengths of this study including the study's large sample size, uniform use of topical prednisolone acetate 1% (PF, as opposed to other corticosteroid formulations), and application of a clinically important definition of cystoid macular edema (CME). Full-Text PDF