X0306 4 2020-05-05 0001192448 GLAUKOS Corp GKOS 0001705850 Gilliam Joseph E C/O GLAUKOS CORPORATION 229 AVENIDA FABRICANTE SAN CLEMENTE CA 92672 1 CFO, SVP Corporate Development Common Stock 2020-05-05 4 F 0 6900 38.44 D 40066 D Consists of shares withheld by the Issuer with respect to income taxes payable by the Reporting Person upon vesting and delivery of shares of common stock underlying restricted stock units previously granted by the Issuer on May 5, 2017, with the vesting schedule in four equal installments on May 5, 2018, May 5, 2019, May 5, 2020 and May 5, 2021. Includes 20,056 restricted stock units that have not yet vested or been delivered to the Reporting Person. /s/ Robert L. Davis, Attorney-in-Fact 2020-05-07