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

R&D Day 2019 Update on Research

Programs February 28, 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 February 28, 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.

Agenda Opening WelcomeTodd Brady, CEO

Corporate Strategy & Pipeline GrowthDavid McMullin, CCO Proliferative Vitreoretinopathy - A Rare Retinal DiseaseDean Eliott, M.D. Harvard Medical School Mass. Eye and Ear Infirmary Ocular Disease Area Program UpdatesDavid Clark, CMO Ocular

Disease Area Market OpportunitiesChris Pearson, VP Commercial ConclusionTodd Brady, CEO Q&A

Our Mission Developing Next-Generation

Medicines to Improve the Lives of Patients with Immune-Mediated Diseases ~7% Of Western Society Suffer from some form of immune-mediated disease, and incidence is increasing Disease control elusive despite existing therapies, and thus novel

approaches are needed Unmet Needs 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.

Immune System Imbalance Leads to

Immune-Mediated Disease Stimulation Imbalance Inhibition Imbalance Autoimmune Cancer Immuno-proliferative Allergy Stimulation Inhibition Immune Balance Healthy Imbalance can result in Immune-Mediated Diseases

Deliberate Focus on Ocular Diseases and

Select Systemic Diseases 2004 May 2014 2015 2016 2017 2018 2019 Dry Eye Disease Allergic Conjunctivitis Noninfectious Anterior Uveitis PVR Retinal Disease Sj gren-Larsson Syndrome PTLD Mesothelioma and other rare cancers** Autoimmune

Discovery & Preclinical Ocular Diseases Systemic Diseases RASP = Reactive Aldehyde Species Inhibitor DHFR = Dihydrofolate Reductase Inhibitor Hsp90 = Heat Shock Protein 90 Inhibitor PTLD = Post-Transplant Lymphoproliferative Disorder PVR =

Proliferative Vitreoretinopathy RASP Hsp90 DHFR RASP RASP RASP RASP RASP Hsp90 IPO; First Phase 2 IND filing Founded First Phase 2 Initiations First Phase 2 Completions First Phase 3 Initiations Add'l Phase 2; Add'l Phase 3 Potential

First Phase 3 Completions* *Contingent on funding, regulatory review, and other factors. **Initially supporting Investigator Sponsored Trials upon Hsp90 licensure.

Our Novel Approaches to Address

Immune-Mediated Disease Cell Activation Cell Proliferation Immune Cell Stimulus Hsp90 Inhibitors RASP Inhibitors DHFR Inhibitors RASP = Reactive Aldehyde Species DHFR = Dihydrofolate Reductase Hsp90 = Heat Shock Protein 90 Reproxalap ADX-103 ADX-629

ADX-1612 ADX-1615 ADX-2191

Ocular Inflammation Deep and Innovative

Pipeline Focused on Immune-Mediated Diseases Ocular Diseases Indication Compound Disease Area Preclinical Phase 1 Phase 2 Phase 3 Next Anticipated Milestone = Positive Phase 2 clinical trial data reported in 2016 - 2018 Trial initiations

contingent on funding, regulatory review, and other factors RASP = Reactive Aldehyde Species Inhibitor DHFR = Dihydrofolate Reductase Inhibitor Hsp90 = Heat Shock Protein 90 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-Part 1 initiation H1 2019 Phase 3 results early 2019 Phase 3 results H2 2019 Phase 3-Part 1 results H2 2019 Phase 3-Part 1 initiation H2 2019 Phase 1 initiation H2 2019 Phase 2 initiation H1 2019 Phase 1/2 initiation 2020 Phase

2 initiation H2 2019 [Mechanism] [RASP] [RASP] [RASP] [RASP] [RASP] [Hsp90] [Hsp90] [DHFR]

Helio Vision Acquisition Expands

Pipeline in Support of Our Strategic Growth Plans Retinal disease a strategic priority for pipeline growth Novel therapeutic approach leveraging an immunological mechanism that diminishes inflammation and cell proliferation Addition of Phase 3-ready

clinical program Orphan drug designation for proliferative vitreoretinopathy, a potentially blinding disease with no approved treatment Potential applicability to a variety of other diseases

Ocular Disease Area Program Updates

Proliferative Vitreoretinopathy Dry Eye Disease Allergic Conjunctivitis Upcoming Milestones

Ocular Disease Area Program Updates

Proliferative Vitreoretinopathy Dry Eye Disease Allergic Conjunctivitis Upcoming Milestones

ADX-2191: Adaptive Phase 3

Proliferative Vitreoretinopathy Clinical Program Expected to Initiate H2 2019 Confirm endpoints, safety and tolerability Confirm sample size for subsequent trial Part 1 controlled, randomized trial design Adaptive Phase 3 Program Phase 3 Program

Design Elements Adaptive Phase 3 (Part 1) PVR Trial Adaptive Phase 3 (Part 2) PVR Trial Confirmatory Phase 3 PVR Trial NDA Illustrative only Expected initiation H2 2019 PVR = Proliferative vitreoretinopathy

Primary objective: Evaluate efficacy

of intravitreal ADX-2191 injections for prevention of recurrent retinal detachment due to proliferative vitreoretinopathy (PVR) Design: Multi-center, non-masked, randomized, controlled, two- part, adaptive Phase 3 clinical trial Inclusion

highlights: Recurrent retinal detachment due to PVR, or Retinal detachment associated with open-globe trauma Dosing regimen: Weekly (x10) then every other week (x3) intravitreal ADX-2191 injections Endpoint: Retinal re-detachments due to PVR

requiring re-operation within 6 months: OCT demonstrating fovea-off retinal detachment Photographic documentation retinal detachment ADX-2191: Adaptive Phase 3 (Part 1) Proliferative Vitreoretinopathy Clinical Trial Design Adaptive Phase 3 PVR

Clinical Trial Design: Part 1 Operative Day 1 Post-Op Week 4 Month 3 ADX-2191 added to routine surgical care (N = 50) Control Arm: Routine surgical care (N = 50) ADX-2191 intravitreal injection treatment Post-Op Week 8 Post-Op Week 12 Post-Op Week

24 Post-Op Week 16 Month 4 Month 5 Month 6 Month 2 Month 1 OCT = Optical Coherence Tomography

Ocular Disease Area Program Updates

Proliferative Vitreoretinopathy Dry Eye Disease Allergic Conjunctivitis Upcoming Milestones

Reproxalap: Adaptive Phase 3 Dry Eye

Disease Clinical Program Expected to Initiate H1 2019 Adaptive Phase 3 Program Phase 3 Program Design Elements Adaptive DED Phase 3 (Part 1) Adaptive DED Phase 3 (Part 2) Confirmatory DED Phase 3 NDA Illustrative only Expected initiation H1 2019

Phase 3 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

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 Reproxalap: Adaptive Phase 3 (Part 1) Dry Eye Disease Clinical Trial Design 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

Reproxalap: Adaptive Phase 3 (Part

2) Dry Eye Disease Clinical Trial Design 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 Treatment Regimen tbd (QID

or QID to BID) Phase 3 Dry Eye Disease Clinical Trial: Part 2 Visit 3 Wk 1 Visit 6 Week 6 Visit 8 Week 10 Reproxalap 0.25% (N = 200-400) Vehicle (N = 200-400) Phase 3 Dry Eye Disease Clinical Trial: Part 1 Phase 3 Dry Eye Disease Clinical Trial:

Part 2 Primary objective: Evaluate efficacy of reproxalap ophthalmic solution (0.25%) vs. vehicle on co-primary symptom and sign endpoints Population selection and design: Same as Part 1 Confirmed sample size Confirmed dosing regimen

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 DED Primary Sign Endpoint for Phase 3 DED p values subject to change based on quality control analysis 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

Ocular Disease Area Program Updates

Proliferative Vitreoretinopathy Dry Eye Disease Allergic Conjunctivitis Upcoming Milestones

Reproxalap: ALLEVIATE Phase 3 Trial

Design in Allergic Conjunctivitis Phase 3 Conjunctival Allergen Challenge Trial Primary objective: Evaluate efficacy of reproxalap ophthalmic solutions (0.25% & 0.5%) compared to vehicle for the treatment of ocular itching associated with acute

allergic conjunctivitis Inclusion/exclusion highlights: Positive history of ocular allergies and positive skin test reaction to a seasonal allergen Positive bilateral conjunctival allergen challenge (CAC) reaction of 2.5 for itching and

2 for redness within 10 min of allergen instillation at first baseline visit Positive bilateral CAC reaction for at least two out of first three time points following challenge at second baseline visit Endpoints: Ocular itch score area under

the curve (primary) Two-point responder comparison (key secondary) Results expected to be announced early 2019 Further information can be found on www.clinicaltrials.gov: Trial #NCT03494504. ALLEVIATE is the first of two required Phase 3 clinical

trials, pending regulatory review. In preparation for a subsequent Phase 3 clinical trial, Aldeyra is conducting clinical method development studies to assess the feasibility of measuring ocular itching following environmental exposure to allergen.

Reproxalap Administration Allergen Challenge Patient Reported Itch Assessment A-1 A0 A1 A2 A3 A4 A5 A6 A7 -10 10 20 30 40 50 60 Time (in minutes) Reproxalap 0.25% (N = 100) Vehicle (N = 100) Reproxalap 0.5% (N = 100)

Reproxalap: AC Ocular Itch Area

Under The Curve and Responder Endpoints Achieved in Phase 2b Clinical Trial Source: Reproxalap AC Phase 2b clinical trial results (~30 patients per arm, seasonal allergy) Area Under the Curve: Ocular Itch Score (0-4) Probability of 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 AC = Allergic

Reproxalap's Novel Mechanism

of Action has the Potential to Provide More Durable Activity Than Antihistamines Reproxalap has the potential to be uniquely effective in post-histaminic allergy, for which no drug is approved, and which affects all allergic conjunctivitis patients.

Histaminic Phase Post-Histaminic Phase (RASP-Mediated) (Cells, cytokines, and other aldehyde-stimulated factors) Reproxalap Activity Antihistamine Activity Allergen 0 10 20 30 40 50 60 Minutes Following Single Exposure to Allergen RASP = Reactive

AC Phase 3 CAC Reproxalap: Parallel

Dry Eye Disease and Allergic Conjunctivitis Phase 3 Clinical Programs Support Concurrent NDA Filings Adaptive DED Phase 3 (Part 1) Adaptive DED Phase 3 (Part 2) Confirmatory DED Phase 3 Expected initiation H1 2019 Phase 3 DED Safety Study Phase 3 AC

Safety Study AC Phase 3 Design to be confirmed Results expected early 2019 NDA Dry Eye Disease Adaptive Phase 3 Clinical Program Allergic Conjunctivitis Phase 3 Clinical Program Illustrative only Type C FDA Meeting DED = Dry eye disease AC =

Allergic conjunctivitis

Ocular Disease Area Program Updates

Proliferative Vitreoretinopathy Dry Eye Disease Allergic Conjunctivitis Upcoming Milestones

Multiple Upcoming Ocular Disease

Area Clinical Program Milestones 2019 2020 Early 2019: Reproxalap ALLEVIATE Phase 3 allergic conjunctivitis trial Results H1 2019: Reproxalap Phase 3 dry eye disease clinical trial program Initiate H2 2019: Reproxalap SOLACE Phase 3 noninfectious

anterior uveitis trial Results H2 2019: ADX-2191 Phase 3 proliferative vitreoretinopathy clinical trial program Initiate 2020: ADX-103 Phase 1/2 retinal disease clinical trial Initiate *Contingent on funding, regulatory review, and other factors.