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Preliminary Proxy Statement

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Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

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Definitive Proxy Statement

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Definitive Additional Materials

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Soliciting Material Pursuant to §240.14a-12

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No fee required.

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Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

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Fee paid previously with preliminary materials.

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Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

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Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to Be Held on June 17, 2021 Your Vote Counts! KALA PHARMACEUTICALS, INC. 2021 Annual Meeting June 17, 2021 9:00 AM, ET Virtual Meeting Site: www.virtualshareholdermeeting.com/KALA2021 KALA PHARMACEUTICALS, INC. 490 ARSENAL WAY, SUITE 120 WATERTOWN, MA 02472 D45221-P54571 You invested in KALA PHARMACEUTICALS, INC. and it’s time to vote! You have the right to vote on proposals being presented at the Annual Meeting. Get informed before you vote View the Notice and Proxy Statement and Annual Report online OR you can receive a free paper or email copy of the material(s) by requesting prior to June 3, 2021. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. Vote in Advance of the Meeting Vote by June 16, 2021 11:59 PM, ET Visit: www.ProxyVote.com Smartphone users Point your camera here and vote without entering a control number Vote Virtually at the Meeting* Vote on June 17, 2021 9:00 AM, ET Visit: www.virtualshareholdermeeting.com/KALA2021 *Please check the meeting materials for any special requirements for meeting attendance. V1 To view the proxy materials and to vote, visit www.ProxyVote.com Control #

Vote at www.ProxyVote.com THIS IS NOT A VOTABLE BALLOT This is an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. Please follow the instructions on the reverse side to vote these important matters. Board Recommends Voting Items D45222-P54571 Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Sign up for E-delivery”. 1. Election of two Class I Directors Nominees: 01) Andrew I. Koven 02) Gregory D. Perry For 2. To ratify the appointment of Deloitte & Touche LLP as Kala Pharmaceuticals, Inc.’s independent registered public accounting firm for the fiscal year ending December 31, 2021. For NOTE: To transact such other business as may properly come before the meeting or any adjournment thereof.