wondered whether the authors had any insights into whether smoking status differed in each tertile of the a-crystallin index, and might increase unbound a-crystallin, thereby causing cataract? Given that common genetic variants in the CRYAA gene were recently associated with nuclear cataract formation in Asians, 3 we were wondering whether the authors have DNA or genetic data available for the participants in the study, to explore associations between depletion of a-crystallin and genetic variants in CRYAA gene. We have measured nuclear cataract in 324 female twins (TwinsUK cohort) at 2 time points (on average 9.7 years apart) by calculating the pixel density in the center of the nucleus from Scheimpflug images as previously described. 4 We have previously nominally replicated the association between CRYAA variants and cross-sectional nuclear cataract (P ¼ 0.01 at rs870137). 5 We explored whether this same variant was also associated with cataract progression in the 324 twins. This was done using a score-based test (MERLIN), adjusting for age. We report here that we also find an association between rs870137 and cataract progression (P ¼ 0.01). Our data suggest that common variants in the CRYAA gene may influence the prevalence and progression of nuclear cataract, and it would be fascinating to find out whether these variants influence the a-crystallin index. EKATERINA YONOVA-DOING, MSC 1 CHRISTOPHER J. HAMMOND, MD, PHD 1,2 1 Department of Twin Research and Genetic Epidemiology; 2 Department of Ophthalmology, King’s College London, London, UK Financial Disclosures: The authors have no proprietary or commercial interest in any materials discussed in this article. Correspondence: Christopher J. Hammond, MD, PhD, King’s College London, Twin Research and Genetic Epidemiology, St. Thomas Hospital, Westminster Bridge Road, 3rd Floor, London, UK. E-mail: chris.hammond@kcl.ac.uk. References 1. Datiles MB 3rd, Ansari RR, Yoshida J, et al. Longitudinal study of age-related cataract using dynamic light scattering: loss of alpha-crystallin leads to nuclear cataract development. Ophthalmology 2016;123:248–54. 2. Datiles MB 3rd, Ansari RR, Suh KI, et al. Clinical detection of precataractous lens protein changes using dynamic light scat- tering. Arch Ophthalmol 2008;126:1687–93. 3. Liao J, Su X, Chen P, et al. Meta-analysis of genome-wide as- sociation studies in multiethnic Asians identifies two loci for age-related nuclear cataract. Hum Mol Genet 2014;23:6119–28. 4. Hammond CJ, Snieder H, Spector TD, Gilbert CE. Genetic and environmental factors in age-related nuclear cataracts in mono- zygotic and dizygotic twins. N Engl J Med 2000;342:1786–90. 5. Yonova EH, Nag A, Hysi PG, et al. Genome-wide association study of nuclear cataract finds suggestive association with a common variant in TRPM3. Invest Ophthalmol Vis Sci 2015;56:5815. REPLY: We thank Drs Ekaterina Yonova-Doing and Christopher J. Hammond for their interest in our paper 1 and would like to respond to their questions. With regard to lens brunescence, we used the Age-Related Eye Disease Study Cataract Clinical Grading System, which in contrast with the Lens Opacities Classification System, does not grade brunescence separately from opalescence. Brunescence is typically a later feature in nuclear cataract. The advantage of the dynamic light scattering system is that it can detect lens protein changes in the precataractous stages, when the lens is still transparent. Thus, at the time when dynamic light scattering is most useful, brunescence will generally not be an issue. We agree that smoking is associated with increased risk of nuclear sclerosis and we would expect smoking to be associated with a decrease in a-crystallin index. However, we did not assess risk factors and did not know the smoking status of the individual patients. We did not perform genetic analysis in this study, but it could be an important feature in future studies. MANUEL B. DATILES, III, MD 1 FREDERICK FERRIS, III, MD 1 RAFAT R. ANSARI,PHD 2 J. SAMUEL ZIGLER, Jr., PHD 3 1 Office of the Clinical Director, National Eye Institute, National Institutes of Health, Bethesda, Maryland; 2 National Aeronautics and Space Administration (NASA), Glenn Research Center, Cleveland, Ohio; 3 Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland Financial Disclosures: The authors have no proprietary or commercial interest in any materials discussed in this article. Correspondence: Manuel B. Datiles III, MD, Office of the Clinical Director, National Eye Institute, National Institutes of Health, 10 Center Drive, Building 10, Room 1, Bethesda, MD 20892-1860. E-mail: Datilesm@nei.nih.gov. Reference 1. Datiles MB 3rd, Ansari RR, Yoshida J, et al. Longitudinal study of age-related cataract using dynamic light scattering: loss of a-crystallin leads to nuclear cataract development. Ophthalmology 2016;123:248–54. Re: Jabbarvand et al.: Endophthalmitis occurring after cataract surgery: outcomes of more than 480 000 cataract surgeries, epidemiologic features, and risk factors (Ophthalmology 2016;123:295-301) TO THE EDITORS: This correspondence concerns the results of the study by Jabbarvand et al. 1 As per the results, 112 of 480 104 cases that underwent cataract surgery at a single hospital between 2006 and 2014 developed endophthalmitis. However, of the 25 920 cases where intracameral cefuroxime was injected, none developed endophthalmitis. This study also found that short-term pretreatment with topical or systemic antibiotics or postoperative subconjunctival injection of antibiotics reduced the odds of endophthalmitis by 40% to 50%, but the difference was not sig- nificant (P ¼ 0.2). The authors concluded from their results that intracameral cefuroxime was 100% effective in preventing post- cataract surgery endophthalmitis. We would like to put forth our observations regarding 2 statistical concepts, sample size, and risk reduction. Ophthalmology Volume 123, Number 8, August 2016 e48