Smoking is associated with higher IOP regardless of glaucoma, a retrospective study of 12.5 million patients using the IRIS® Registry

Abstract Purpose To compare the average intraocular pressure (IOP) between smokers, past smokers, and never smokers using the American Academy of Ophthalmology (AAO) IRIS® Registry (Intelligent Research in Sight). Design Retrospective database study of the IRIS Registry data. Subjects IRIS Registry patients who were seen by an eye care provider during 2017. Methods Patients were divided into current smoker, past smoker, and never smoked categories. The IOP was based on an average measurement, and separate analyses were performed in patients with and without a glaucoma diagnosis based on International Classification of Diseases (ICD) 9/10 codes. Stratified, descriptive statistics by glaucoma status were performed, and the relationship between smoking and IOP was assessed with a multivariable linear regression model. Main Outcome Measures Mean intraocular pressure. Results A total of 12,535,013 patients were included. Compared to never smokers, current and past smokers had statistically significantly higher IOP by 0.92 mmHg (95% CI: 0.88-0.95 mmHg) and 0.77 mmHg (95% CI: 0.75-0.79 mmHg), respectively, after adjusting for age, sex, glaucoma, age-related macular degeneration, diabetic retinopathy, cataract, glaucoma surgery, cataract surgery, and first order interactions. In addition, the difference in IOP between current and never smokers was the highest in the fourth decade regardless of the glaucoma status (glaucoma group: 1.14 mmHg [95% CI: 1.00-1.29 mmHg]; without glaucoma group: 0.68 mmHg, [95% CI: 0.65-0.71 mmHg]). Conclusion Current smokers and past smokers have higher IOP than patients who never smoked. This difference is higher in patients with underlying glaucoma diagnosis.