X0306 4 2019-09-30 0 0001341235 Aldeyra Therapeutics, Inc. ALDX 0001579179 Brady Todd C C/O ALDEYRA THERAPEUTICS, INC. 131 HARTWELL AVENUE LEXINGTON MA 02421 1 1 0 0 President and CEO Common Stock 2019-09-30 4 P 0 8710 5.6812 A 632216 D The purchase of these shares was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 30, 2019. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $5.41 to $5.86, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in this footnote (2) to this Form 4. /s/ Todd C. Brady 2019-10-02