Thank you for your inquiry on CMS133v12 Cataracts: 20/40 or Better Visual Acuity within 90 Days Following Cataract Surgery. The measure is an episode-based measure. An episode for this measure is defined as each cataract surgery during the measurement period, including instances where more than one cataract procedure was performed during the measurement period. Every cataract surgery during the measurement period is counted as a measurable denominator event. The first cataract surgery performed on the patient’s left eye would not qualify for a denominator exclusion. The second cataract surgery to the patient’s right eye would qualify for a denominator exclusion if the reporting entity documented a “significant ocular condition.” This clinical concept can be found in the measure specifications for CMS133v12 ( https://ecqi.healthit.gov/sites/default/files/ecqm/measures/CMS133v12.html ).