Disclaimers and Forward-Looking Statements This presentation and various remarks which may be made during this presentation contain forward-looking statements within the meaning of the Private Securities Litigation Refor

Innovating Transformative Therapies

JEFFERIES 2019 HEALTHCARE CONFERENCE Nasdaq: ALDX Aldeyra Therapeutics, Inc. 2019 June 2019 Exhibit 99.1

Disclaimers and Forward-Looking

Statements This presentation and various remarks which may be made during this presentation contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and Section 21E of the Securities Exchange Act

of 1934, as amended, including statements regarding Aldeyra's possible or assumed future results of operations, expenses and financing needs, business strategies and plans, research and development plans or expectations, trends, the structure,

timing and success of Aldeyra's planned or pending clinical trials, expected milestones, market sizing, pricing and reimbursement, competitive position, regulatory matters, industry environment and potential growth opportunities, among other

things. Forward-looking statements include all statements that are not historical facts and, in some cases, can be identified by terms such as "may," "might," "will," "objective," "intend,"

"should," "could," "can," "would," "expect," "believe," "anticipate," "project," "target," "design," "estimate,"

"predict," "potential," "plan" or similar expressions and the negatives of those terms. Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause Aldeyra's

actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. These statements reflect Aldeyra's current views with respect

to future events and are based on assumptions and subject to risks and uncertainties, including the development, clinical and regulatory plans or expectations for Aldeyra's product candidates and Aldeyra's continuing review and quality

control analysis of clinical data. Important factors that could cause actual results to differ materially from those reflected in Aldeyra's forward-looking statements are described in Aldeyra's most recent Annual Report on Form 10-K and

Quarterly Report on Form 10-Q, as well as Aldeyra's subsequent filings with the Securities and Exchange Commission. All of Aldeyra's development timelines may be subject to adjustment depending on recruitment rate, regulatory review,

preclinical and clinical results, and other factors that could delay the initiation, completion, or reporting of clinical trials. In addition to the risks described above and in Aldeyra's other filings with the SEC, other unknown or unpredictable

factors also could affect Aldeyra's results. No forward-looking statements can be guaranteed and actual results may differ materially from such statements. The information in this presentation is provided only as of June 6, 2019, and Aldeyra

undertakes no obligation to update any forward-looking statements contained in this presentation on account of new information, future events, or otherwise, except as required by law.

Our Mission Developing Next-Generation

Medicines to Improve the Lives of Patients with Immune-Mediated Diseases Suffer from some form of immune-mediated disease, and incidence is increasing Disease control elusive despite existing therapies, and thus novel approaches are needed Source:

Lerner, Jeremias, and Matthias, International Journal of Celiac Disease, vol. 3, no. 4 (2015): 151-155; Shurin and Smolkin, Advances in Experimental Medicines and Biology 601:3-12, 2007; Kuek et al, Postgraduate Medical Journal 83(978): 251-260,

2007. ~7% Of Western Society Unmet Needs

Deep and Innovative Pipeline Focused on

Immune-Mediated Diseases Ocular Inflammation Ocular Diseases Indication Compound Disease Area Preclinical Phase 1 Phase 2 Phase 3 Next Anticipated Milestone = Positive Phase 2/3 clinical trial data reported in 2016-2019 Trial initiations contingent

on funding, regulatory review, and other factors RASP Mechanism = Reactive Aldehyde Species Inhibitor DHFR Mechanism = Dihydrofolate Reductase Inhibitor ECHP Mechanism = Epichaperome Inhibitor PTLD = Post-Transplant Lymphoproliferative

Disorder Proliferative Vitreoretinopathy ADX-2191 Reproxalap Dry Eye Disease Allergic Conjunctivitis Noninfectious Anterior Uveitis ADX-103 Retinal Disease ADX-629 Autoimmune Disease ADX-1612 PTLD Mesothelioma Ovarian Cancer Reproxalap

Sj gren-Larsson Syndrome Undisclosed Systemic Inflammatory Disease ADX-1615 Autoimmune Disease / Cancer Undisclosed Systemic Diseases Investigator-Sponsored Trial Research Collaboration Research

Collaboration (undisclosed) Phase 3 results H2 2019 Phase 3-Part 1 completion H2 2019 Phase 3-Part 1 initiation H2 2019 Phase 1 initiation H2 2019 Phase 2 initiation 2019 Phase 1/2 initiation 2020 Phase 2 initiation 2019 [Mechanism] [RASP] [RASP]

[RASP] [RASP] [RASP] [ECHP] [ECHP] [DHFR]

Reproxalap: Phase 3 Reproxalap: Phase 3

Drug Candidate and Dev. Stage Reproxalap: Phase 3 ADX-2191: Phase 3 Reproxalap: Phase 3 Pricing Benchmarks $500-550 per month (dry eye disease pricing) $1,500 per regimen (to treat one flare) $30,000 per course (avg. cost of surgeries)

$200,000 - $400,000 per year Xiidra , Restasis Antihistamines Current Standard of Care Corticosteroids None (repeat surgeries) None (manage symptoms) Our Lead Programs May Offer Potential Benefits Over Standard of Care Dry Eye Disease

Allergic Conjunctivitis Noninfectious Anterior Uveitis Sj gren-Larsson Syndrome Late Stage Programs Ocular Diseases Systemic Diseases Proliferative Vitreoretinopathy Rapid onset, broad activity, reduction in itch Non-drying, durable activity;

Responder superiority vs. vehicle Potential Competitive Advantages No expected risk of glaucoma or other corticosteroid toxicities Clinically demonstrated activity; Currently no FDA- or EMA-approved therapy Clinically demonstrated activity;

Currently no FDA- or EMA-approved therapy Pending clinical data, regulatory discussions, payor negotiations, competition, potential legislative changes, and other factors, which may not be in Aldeyra's control. Preliminary assumptions

are subject to change. Source: Aldeyra internal estimates based on primary and secondary market research; published literature

DRY EYE DISEASE ALLERGIC CONJUNCTIVITIS

NONINFECTIOUS ANTERIOR UVEITIS PROLIFERATIVE VITREORETINOPATHY Ocular Disease Area Nasdaq: ALDX Aldeyra Therapeutics, Inc. 2019 June 2019

Reproxalap in DED Early and consistent

symptom and sign improvements in Phase 2b clinical trial Broad symptom and sign improvements in Phase 2b clinical trial Dry Eye Disease: Persistently Disturbing Disease with Inadequate Therapy Dry Eye Disease Women are twice as likely to suffer from

DED than men vs Significant negative quality of life impact 20 million or more adults in the U.S. suffer from DED 20 million DED increases with age, with those over age 50 three times more likely to suffer from DED Age 50+ >3x Source: Aldeyra

internal estimates based on primary and secondary market research; published literature DED = Dry eye disease Current Rx options may require up to six weeks or longer to achieve even modest efficacy Up to 75% of patients with DED are not satisfied

with current prescription options Up to 75% Up to 50% of patients treated for DED with current therapies fail and discontinue Up to 50% Underserved Patient Population Reproxalap

Dry Eye Disease Symptom and Sign

Endpoints Achieved in Phase 2b Clinical Trial Mean Change from Baseline OD & 4-Symptom Questionnaire: Dryness (0-5) Baseline Score > 3 (N=69|69) Fluorescein Staining: Nasal (0-4) Baseline Score > 2 (N=62|56) Primary Symptom Endpoint for

Phase 3 Primary Sign Endpoint for Phase 3 Source: Reproxalap DED Phase 2b clinical trial results * * ** * ** ** * *p<0.05 **p<0.01 OD = Ocular Discomfort MMRM = Mixed Effect Model Repeated Measures MMRM p = 0.0048 MMRM p = 0.0007

Dry Eye Disease Symptoms Broad Pattern

of Drug Activity Across Dry Eye Disease Symptoms and Signs Supports Differentiated Product Profile Improvement Effect Size at Week 12 Dry Eye Disease Signs Improvement Effect size = Change from Baseline / Standard Deviation at Baseline Source:

Reproxalap DED Phase 2b clinical trial results SANDE = Symptom Assessment in Dry Eye Average improvement effect size across both eyes for tear quality and tear quantity measures (Schirmer's Test, Tear Film Break-Up Time, and

Dry Eye Disease Clinical Program

Adaptive Phase 3 Dry Eye Disease Clinical Program Adaptive Phase 3 Program RENEW Phase 3 (Part 1) RENEW Phase 3 (Part 2) Confirmatory DED Phase 3 NDA Initiated April 2019 DED Safety Study Adaptive design, co-primary endpoints, and innovative

analysis strategy confirmed with FDA at EOP2 Meeting Confirm dosing regimen (QID vs. QID to BID taper) Confirm sample size for subsequent trial Confirm symptom and sign endpoints from Phase 2b trial DED = Dry eye disease BID = Two times daily QID =

Four times daily EOP2 = End of Phase 2 Contingent on funding, regulatory review, and other factors Formulation Trial Initiated April 2019

RENEW Trial Design in Dry Eye

Disease Adaptive Phase 3 (Part 1) Clinical Trial Initiated April 2019 Primary objective: Evaluate efficacy of reproxalap ophthalmic solution (0.25%) vs. vehicle to confirm dosing regimen and sample size for Part 2 Inclusion/exclusion criteria: Same

as used for Phase 2b Moderate to severe dry eye disease Co-primary endpoints: Ocular dryness score (0-100mm VAS) and fluorescein nasal region staining Analysis strategy: Both co-primary endpoints will be assessed using Mixed Model Repeated Measures

(MMRM) from week 2 to week 12 Both co-primary endpoints will be assessed based on separate pre-specified patient populations Ocular dryness score (OD4SS): baseline score of > 3 Fluorescein nasal staining: baseline score > 2 Vehicle -Wk 2 -Wk 1

Wk 1 Wk 2 Wk 3 Wk 4 Wk 5 Wk 6 Wk 7 Wk 8 Wk 9 Wk 10 Wk 11 Wk 12 Visit 1 Week -2 Visit 2 Day 1 Visit 4 Wk 2 Visit 5 Week 4 Visit 7 Week 8 Visit 9 Week 12 Screening Phase 3 Dry Eye Disease Clinical Trial: Part 1 Treatment Visit 3 Wk 1 Visit 6 Week 6

Visit 8 Week 10 Reproxalap 0.25% (N = 100) QID Vehicle (N = 100) QID Reproxalap 0.25% (N = 100) QID to BID* Vehicle (N = 100) QID to BID VAS = Visual analog scale OD4SS = Ocular Discomfort 4-Symptom Score *QID for weeks 1-4 and BID for weeks 5-12

Further information can be found on www.clinicaltrials.gov: Trial #NCT03879863.

DRY EYE DISEASE ALLERGIC

CONJUNCTIVITIS NONINFECTIOUS ANTERIOR UVEITIS PROLIFERATIVE VITREORETINOPATHY Ocular Disease Area Nasdaq: ALDX Aldeyra Therapeutics, Inc. 2019 June 2019

~2% of AC patients have severe

symptoms and may be corticosteroid-dependent 2% Underserved Patient Population Antihistamines are not effective in an estimated 24% of treated AC patients 24% Many AC patients make significant sacrifices due to lack of drug activity AC can result in

acute, intermittent, and chronic symptoms AC patients experience symptoms throughout all decades of adult life 20s AC 40s 60s 80s Significant negative quality of life impact Up to 30 million of AC sufferers in the U.S. do not respond adequately to

or are dissatisfied with antihistamines 30 million Allergic Conjunctivitis Reproxalap Allergic Conjunctivitis: A Common Disease with Unmet Medical Need Source: Aldeyra internal estimates based on primary and secondary market research; published

literature AC = Allergic conjunctivitis Active in post-histaminic allergy, for which no drug is approved Clinically significant and durable symptom response in Phase 3 clinical trial Reproxalap in AC

Novel Mechanism of Action has the

Potential to Provide Differentiated Activity Versus Antihistamines Reproxalap has the potential to be uniquely effective in post-histaminic allergy, which affects all allergic conjunctivitis patients Histaminic Phase Post-Histaminic Phase (Cells,

cytokines, and other RASP-stimulated factors) Reproxalap Activity Antihistamine Activity Allergen 0 10 20 30 40 50 60 Minutes Following Single Exposure to Allergen RASP = Reactive Aldehyde Species Illustrative only, based on published literature and

Reproxalap Showed Greater and More

Durable Clinical Responses vs. Vehicle Group in ALLEVIATE Phase 3 Clinical Trial Source: ALLEVIATE allergic conjunctivitis Phase 3 clinical trial results; Ocular itch scale 0 (no itch) to 4 (incapacitating itch) Area Under the Curve: Ocular Itch

Score (0-4) 10 to 60 Minutes After Allergen Challenge Probability of Two-Point Response: Ocular Itch Score (0-4) Improvement in itch score over one hour after allergen exposure statistically greater for reproxalap vs. vehicle Clinically significant

response rate of reproxalap statistically higher than that of vehicle SEM = Standard error of the mean Primary Endpoint GEE p = 0.0005 GEE = Generalized estimating equation analysis Key Secondary Endpoint * p < 0.05 ** p < 0.01

Reproxalap Showed Greater and More

Durable Clinical Responses vs. Vehicle in Allergen Chamber Clinical Trial 16 Source: Aldeyra Therapeutics methodology development clinical trial (ClinicalTrials.gov #NCT03709121); n=66 Ocular Itch Score (0-100) During 3.5 Hours of Allergen Exposure

Ocular Redness Score (0-4) During 3.5 Hours of Allergen Exposure Statistically significant reduction in ocular itch vs. vehicle for more than three hours of exposure to allergen Statistically significant reduction in ocular redness vs. vehicle for

more than three hours of exposure to allergen MMRM = Mixed Effect Model Repeated Measures MMRM p < 0.0001 MMRM p < 0.0001 First Dose 5 min Before Chamber Entry First Dose 5 min Before Chamber Entry

Allergic Conjunctivitis Phase 3

Clinical Program Design Elements AC Safety Study Additional AC Phase 3 Allergic Conjunctivitis Clinical Program Type C FDA Meeting AC = Allergic conjunctivitis CAC = Conjunctival Allergen Challenge NDA ALLEVIATE Phase 3 (CAC) Results March 2019

Contingent on funding, clinical results, regulatory review, and other factors. Methods Development Trials (Environment / Chamber) Results June 2019

DRY EYE DISEASE ALLERGIC

CONJUNCTIVITIS NONINFECTIOUS ANTERIOR UVEITIS PROLIFERATIVE VITREORETINOPATHY Ocular Disease Area Nasdaq: ALDX Aldeyra Therapeutics, Inc. 2019 June 2019

Noninfectious Anterior Uveitis

Reproxalap Noninfectious anterior uveitis: A Serious Inflammatory Disease With Inadequate Current Therapy Source: Aldeyra internal estimates based on primary and secondary market research; published literature NAU = Noninfectious anterior uveitis

SOC = Standard of Care Acute Recurrent Chronic ~50% of NAU patients have recurrent or chronic conditions requiring multiple interventions per year Steroids Corticosteroids are currently SOC and require monitoring due to serious toxicities Prolonged

usage may lead to glaucoma, cataracts, corneal ulceration, and other serious side effects Noninfectious anterior uveitis (NAU) is the most common form of uveitis, with an estimated 260,000 U.S. patients per year 260K annually Reproxalap A novel and

differentiated approach to treat NAU Reduced anterior chamber cell count in a Phase 2 clinical trial, and was statistically non-inferior to corticosteroid treatment Safety and tolerability without intraocular pressure increase in a Phase 2 clinical

trial SOLACE Phase 3 clinical trial results expected H2 2019

Reproxalap Reduced Inflammation in

Noninfectious Anterior Uveitis Phase 2 Clinical Trial Reproxalap was statistically non-inferior to corticosteroid in a noninfectious anterior uveitis Phase 2 clinical trial Source: Reproxalap NAU Phase 2b clinical trial results Proportion Cured

(Grade 0 = no inflammatory cells observed) Week 4 Grade 0 Percent of Subjects Reproxalap 53% (8/15) Corticosteroid 38% (5/13) Mean Change from Baseline Day 4 Day 7 Day 14 Day 28 Change from Baseline in Anterior Chamber Inflammatory Cell Grade ITT

Population with Last Observation Carried Forward

Reproxalap Did Not Increase

Intraocular Pressure in Noninfectious Anterior Uveitis Phase 2 Clinical Trial Increase in intraocular pressure, which may lead to glaucoma, is a major corticosteroid toxicity that is not apparent with reproxalap Source: Reproxalap NAU Phase 2b

clinical trial results Mean Change from Baseline Day 4 Day 7 Day 14 Day 28 Day 56 Change from Baseline in Intraocular Pressure (mmHg) Safety Population

SOLACE Trial Design in Noninfectious

Anterior Uveitis Phase 3 Clinical Trial Initiated April 2017 Primary objective: Evaluate efficacy of reproxalap ophthalmic solution (0.5%) on anterior chamber cell count (ACC) vs. vehicle Inclusion highlights: Acute endogenous NAU with onset of

symptoms within the previous 2 weeks 6-50 ACC in the study eye Intraocular pressure <21 Dosing regimen: Week 1 8x/day Week 2 6x/day Weeks 3-4 4x/day Week 5None Endpoints: Time-to-cure (zero inflammatory cells in anterior chamber) without rescue

Results expected to be announced H2 2019 Phase 3 Noninfectious Anterior Uveitis Trial Visit 1 (Screening) Day 1 Visit 2 Day 4 Visit 4 Wk 2 (Day 15) Visit 5 Week 3 (Day 22) Visit 7 Week 5 (Day 36) Visit 3 Wk 1 (Day 8) Visit 6 Week 4 (Day 29) Wk 1 Wk

2 Wk 3 Wk 4 Wk 5 Reproxalap 0.5% (N 110) Vehicle (N 110) Treatment Further information can be found on www.clinicaltrials.gov: Trial #NCT03131154.

DRY EYE DISEASE ALLERGIC