EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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ASCRS NEWS BCVA was included and was reported from the date nearest surgery during the interval from 3 weeks to 1 year after cataract extraction. No data was offered regarding the specific postop time the BCVA was taken from in the different groups. In patients with diabetes, who are more prone to postoperative cystoid macular edema (CME), BCVA could have been measured before, during, or after the expected peak of CME. It is important to note the exclusion of pa- tients with type 1 diabetes. While type 2 diabetes represents 90–95% of all diabetes cases in the U.S., there are several million patients with type 1 diabetes, and providers should be cautious in extrapolating these results when counseling those individuals. 1 The authors also elected to exclude complex phacoemulsification cases but did not describe whether patients with diabetes or diabet- ic retinopathy were more likely to have a complex phacoemulsification and thus be excluded. Previ- ous work has suggested that patients with diabe- tes can have more iris pigment epithelial changes and miotic pupils, increased corneal epithelial and endothelial fragility, impaired corneal wound heal- ing, higher rates of cystoid macular edema, and increased risk of vitreous hemorrhage. 8,9,10 No data was presented regarding the rates of compli- cations, which are extremely important in elective cataract surgery. The general improvement in lines of vision gained in patients with diabetes does not preclude a significant difference in complica- tion rates compared to patients without diabetes. Regardless of any limitations of this report, it is very useful to know that patients with all grades of DR severity saw an improvement in visual acuity following cataract surgery and that uncon- trolled HbA1c levels did not portend poor visual outcomes. This study is an important step toward understanding these complex patients in the context of cataract surgery. Additional research is needed to fully inform timing of cataract surgery, counsel these patients appropriately, and maxi- mize visual outcomes. DME is due to the accumulation and exudation of extracellular fluid within the macula second- ary to increased vascular impermeability, which can greatly worsen following cataract surgery. 4 The prevalence of DME in patients with type 1 diabetes is between 4.2 and 7.9% and in patients with type 2 diabetes is between 1.4 and 12.8%, representing a significant proportion of the DR population. 5 The Diabetic Retinopathy Clinical Research Network has two limited reports on the outcomes following cataract surgery in their population of patients. One of these reports an- alyzed patients without central-involving diabetic macular edema (CI-DME) at the time of cata- ract surgery and the other enrolled patients with preoperative CI-DME. 6,7 In the study examining those eyes without CI-DME, it was reported that any history of treatment for DME prior to treatment increased the risk of developing DME following cataract surgery. The second study was a pilot study examining visual outcomes of 63 eyes with CI-DME that underwent cataract surgery but was discontinued due to slow enroll- ment. This problem represents a substantial and particularly vulnerable subset of patients under- going cataract surgery, and we greatly anticipate the findings of the authors' planned report on patients with DME. Interestingly, only 41% of diabetic patients had a HbA1c drawn in the 90 days prior to surgery. Given that the HbA1c level was only included if it was measured in that time period, it would have been beneficial to see whether extend- ing the cutoff to 6 months prior to the surgery (and thus increasing the number of patients with preoperative HbA1c) would have impacted any of the associations between preoperative HbA1c and postoperative BCVA. Moreover, 30% of those with severe NPDR and PDR had no postopera- tive visual acuity up to 1 year following surgery. Given that these two categories of patients represent the most severe DR, it is disappointing that approximately one-third of these patients did not have postoperative outcomes data. The method of measuring postoperative BCVA could also introduce uncertainty. One postoperative APRIL 2019 | EYEWORLD | 25 References 1. Centers for Disease Control and Prevention. National Diabetes Statistics Report, 2017. Atlanta, GA: Centers for Disease Control and Prevention, US Department of Health and Human Services; 2017. 2. Becker C, et al. Cataract in patients with diabetes melli- tus-incidence rates in the UK and risk factors. Eye (Lond). 2018;32:1028–1035. 3. Buchleitner AM, et al. Perioperative glycaemic control for diabetic patients undergoing surgery. Cochrane Database Syst Rev. 2012:CD007315. 4. Das A, et al. Diabetic macular edema: Pathophysiology and nov- el therapeutic targets. Ophthal- mology. 2015;122:1375–94. 5. Lee R, et al. Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss. Eye Vis (Lond). 2015;2:17. 6. Diabetic Retinopathy Clinical Research Network Authors/ Writing Committee, et al. Macular edema after cataract surgery in eyes without preoperative central-involved diabetic mac- ular edema. JAMA Ophthalmol. 2013;131:870–9. 7. Diabetic Retinopathy Clinical Research Network Authors/ Writing Committee, et al. Pilot study of individuals with diabetic macular edema undergoing cat- aract surgery. JAMA Ophthalmol. 2014;132:224–6. 8. Yanoff M, et al. Diabetic lacy vacuolation of iris pigment epithe- lium; a histopathologic report. Am J Ophthalmol. 1970;69:201–10. 9. Sanchez-Thorin JC. The cornea in diabetes mellitus. Int Ophthal- mol Clin. 1998;38:19–36. 10. Javadi MA, Zarei-Ghanavati S. Cataracts in diabetic patients: a review article. J Ophthalmic Vis Res. 2008;3:52–65. To view the full abstract online, go to www.jcrsjournal.org and search "Visual outcomes after cataract surgery in patients with type 2 diabetes."