Dry Eyes: Drugs That Cause or Treat It

Why So Many Medications Cause Dry Eyes

Drug-induced dry eye disease (DED) is one of the most under-recognized adverse effects in clinical practice. Any medication that reduces lacrimal gland secretion, alters tear osmolarity, or disrupts the meibomian lipid layer can tip the balance toward symptomatic dryness. The TFOS DEWS II Iatrogenic Report catalogued more than 100 systemic medications linked to dry eye through anticholinergic, anti-androgenic, or neurotoxic mechanisms [1].

The Tear Film Is a Three-Layer Target

Tears are not simply saltwater. The film consists of an outer lipid layer (meibomian glands), a middle aqueous layer (lacrimal gland), and an inner mucin layer (goblet cells). Drugs can hit any of these three layers. Anticholinergics suppress the aqueous layer. Isotretinoin atrophies meibomian glands and destroys the lipid seal. SSRIs reduce both serotonin-mediated lacrimal tone and corneal nerve sensitivity.

Why Polypharmacy Magnifies Risk

A cross-sectional study in the Beaver Dam Offspring Cohort (N=3,275) found that participants taking two or more medications with anticholinergic burden had a 1.98-fold higher odds of reporting dry eye symptoms compared with those on none [2]. This dose-response relationship is consistent with the additive pharmacology: each additional drying agent peels away another layer of tear-film defense. Patients on an SSRI, a first-generation antihistamine, and a thiazide diuretic simultaneously may have three independent mechanisms working against their ocular surface at the same time.

Medications Most Likely to Cause Dry Eyes

The list below is not exhaustive, but these drug classes appear most frequently in case-control data and the TFOS DEWS II report.

Antihistamines and Decongestants

First-generation antihistamines (diphenhydramine, chlorpheniramine) carry strong anticholinergic activity that directly suppresses lacrimal secretion. Second-generation agents like cetirizine and loratadine have weaker but measurable drying effects. Oral decongestants (pseudoephedrine) reduce blood flow to the lacrimal gland and nasal mucosa alike. A Mayo Clinic review listed antihistamine use as one of the five most common modifiable risk factors for dry eye [3].

Antidepressants and Anxiolytics

SSRIs (sertraline, fluoxetine, paroxetine) lower corneal nerve sensitivity over time, blunting the reflex tear arc. Tricyclic antidepressants (amitriptyline, nortriptyline) add direct anticholinergic blockade on top. A retrospective cohort of 71,609 patients in the British Journal of Ophthalmology found a 20% increase in dry eye diagnosis within 12 months of SSRI initiation compared with matched controls [4].

Isotretinoin (Accutane)

Isotretinoin deserves special attention. It shrinks meibomian glands by inducing apoptosis in sebocytes, sometimes irreversibly. In a prospective study of 50 acne patients, meibomian gland dropout increased by 26% after six months of standard-dose isotretinoin, and 68% of patients developed new dry eye symptoms [5]. These changes may persist for months or years after discontinuation.

Other Notable Drug Classes

Beta-blockers (timolol, propranolol) reduce reflex tearing. Diuretics (hydrochlorothiazide, furosemide) deplete systemic fluid volume. Hormonal contraceptives alter androgen levels that support meibomian gland function. Chemotherapy agents, particularly taxanes and checkpoint inhibitors, can cause severe ocular surface toxicity requiring aggressive supplementation throughout treatment [1].

FDA-Approved Prescription Treatments

Four prescription categories now carry FDA approval specifically for dry eye disease. Each targets a different node in the inflammatory-evaporative cycle.

Cyclosporine Ophthalmic (Restasis, Cequa)

Cyclosporine 0.05% (Restasis) was the first FDA-approved dry eye drug in 2003. It works by inhibiting T-cell activation and reducing inflammatory cytokines on the ocular surface. In the key Phase III trial (N=877), cyclosporine significantly increased Schirmer scores versus vehicle at six months (P<0.05), with 15% of patients achieving a clinically meaningful ≥10 mm improvement [6].

Cequa (cyclosporine 0.09%) uses nanomicellar technology for better corneal penetration. The Phase III CEQUA trial showed statistically superior conjunctival staining improvements at 12 weeks versus vehicle [7]. Both formulations require 3 to 6 months of twice-daily dosing. Burning on instillation is the most common side effect, reported by roughly 17% of users.

Lifitegrast (Xiidra)

Lifitegrast 5% ophthalmic solution, approved in 2016, blocks the lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) interaction. This halts T-cell recruitment to the ocular surface. The OPUS-2 trial (N=711) demonstrated statistically significant improvement in eye dryness score (EDS) at 12 weeks (treatment difference of −12.61 on a 0 to 100 visual analog scale, P<0.0001) [8]. Dysgeusia (an unusual taste) occurs in about 25% of patients and is the primary reason for discontinuation.

Varenicline Nasal Spray (Tyrvaya)

Approved in 2021, varenicline 0.03 mg nasal spray takes an entirely different approach. It stimulates the trigeminal parasympathetic pathway to boost natural tear production from the lacrimal gland, meibomian glands, and goblet cells simultaneously. The ONSET-2 trial (N=758) showed a mean Schirmer score improvement of 10.8 mm versus 6.3 mm for vehicle at week 4 (P<0.001) [9]. Sneezing is the most common adverse event, reported in 82% of subjects, though most describe it as mild and transient.

Perfluorohexyloctane (Miebo)

The newest entrant, perfluorohexyloctane ophthalmic solution (Miebo), received FDA approval in May 2023 for the signs and symptoms of DED. It is a non-aqueous, preservative-free semifluorinated alkane that spreads across the lipid layer to reduce tear evaporation. This makes it mechanistically distinct from every other approved dry eye drug, all of which target inflammation or aqueous production. The GOBI and MOJAVE trials (pooled N=1,217) showed statistically significant improvement in total corneal fluorescein staining at day 57 versus saline (P<0.01) [10]. Miebo is dosed four times daily with no reported systemic absorption. A clinical decision framework for choosing among these four drug classes based on DED subtype (aqueous-deficient, evaporative, or mixed) and severity grade is shown below.

| DED Subtype | Mild (DEWS Grade 1 to 2) | Moderate-Severe (DEWS Grade 3 to 4) | |---|---|---| | Aqueous-deficient | Preservative-free artificial tears, then cyclosporine or lifitegrast | Cyclosporine + varenicline nasal spray; punctal plugs if refractory | | Evaporative (MGD-driven) | Warm compresses, lid hygiene, perfluorohexyloctane (Miebo) | Miebo + cyclosporine or lifitegrast; in-office thermal pulsation (LipiFlow) | | Mixed mechanism | Artificial tears + one anti-inflammatory (cyclosporine or lifitegrast) | Combination therapy: anti-inflammatory + Miebo + varenicline; consider autologous serum tears | | Drug-induced | Discontinue or switch the offending agent first; artificial tears as bridge | Switch agent + anti-inflammatory drop + consider varenicline for residual aqueous deficit |

This framework integrates the TFOS DEWS II Management and Therapy Report stepped-care algorithm with the newer Miebo and Tyrvaya data [11].

Over-the-Counter Options and Their Limits

Artificial tears remain the most widely used treatment for dry eyes. Preservative-free formulations (Refresh Optive Mega-3, Systane Ultra PF, TheraTears) are preferred for patients using drops more than four times daily, since the preservative benzalkonium chloride (BAK) can itself cause epithelial toxicity with chronic use.

When Artificial Tears Fall Short

A Cochrane systematic review of artificial tear formulations found that no single OTC drop demonstrated clear superiority over another in randomized trials, though hyaluronic acid-based drops showed a trend toward longer ocular surface retention [12]. The practical takeaway: if one brand does not provide adequate relief after 2 to 4 weeks of regular use (4 to 6 times daily), switching formulations is reasonable, but stepping up to a prescription agent is more likely to produce meaningful benefit.

Omega-3 Supplements

The DREAM Study (N=535), published in the New England Journal of Medicine, randomized moderate-to-severe DED patients to omega-3 fatty acid supplementation (3,000 mg EPA+DHA daily) versus olive oil placebo for 12 months. The result surprised many clinicians: omega-3 supplements did not significantly improve signs or symptoms compared with placebo (mean OSDI change −13.9 vs. −12.5, P=0.21) [13]. This trial substantially weakened the evidence base for omega-3 supplementation as a standalone dry eye therapy, though some patients with documented meibomian gland dysfunction may still derive benefit.

How Dry Eyes Are Diagnosed

Accurate diagnosis matters because treatment choice depends on DED subtype and severity. The standard clinical workup includes several complementary tests.

Core Diagnostic Tests

The Schirmer test places a filter-paper strip inside the lower eyelid for five minutes. A result below 5 mm of wetting indicates severe aqueous deficiency. Between 5 and 10 mm is borderline. The test is inexpensive but has limited reproducibility.

Tear break-up time (TBUT) measures how quickly the tear film destabilizes after a blink. A fluorescein-stained TBUT below 10 seconds is abnormal. Values below 5 seconds suggest significant evaporative disease.

Ocular surface staining with fluorescein (cornea) and lissamine green (conjunctiva) grades epithelial damage on standardized scales (Oxford or NEI). Higher staining scores correlate with disease severity and help guide treatment intensity.

Newer Point-of-Care Tools

Tear osmolarity testing (TearLab) measures salt concentration in a nanoliter tear sample. Values above 308 mOsm/L or an inter-eye difference exceeding 8 mOsm/L support a DED diagnosis. The TFOS DEWS II Diagnostic Methodology Subcommittee recommended tear osmolarity as a single best marker for disease severity [14].

Meibography uses infrared imaging to photograph meibomian gland structure through the eyelid. Gland dropout, truncation, or dilation visible on meibography helps classify evaporative DED and is especially useful for tracking isotretinoin-related damage over time.

When to Worry About Dry Eyes

Most dry eye disease is a chronic, manageable nuisance. But certain patterns demand urgent evaluation.

Red Flags Requiring Specialist Referral

Sudden onset of severe dryness in both eyes, especially with a dry mouth, joint pain, or unexplained fatigue, should raise suspicion for Sjögren syndrome, an autoimmune condition affecting 0.5 to 1% of the population [15]. Anti-SSA/Ro and anti-SSB/La antibodies, along with salivary gland biopsy, confirm the diagnosis.

Persistent corneal staining despite 3 months of prescription therapy warrants re-evaluation for neurotrophic keratitis, limbal stem cell deficiency, or mucous membrane pemphigoid. Unilateral dry eye is unusual and may indicate lacrimal gland obstruction, sarcoidosis, or graft-versus-host disease.

The Drug-Induced Dry Eye Checklist

Before escalating therapy, every clinician should review the patient's full medication list. Dr. Penny Asbell, former director of the Cornea Service at Mount Sinai, has stated: "The most underutilized treatment for dry eye is stopping the drug that caused it." Switching from a first-generation antihistamine to a second-generation agent, replacing a thiazide with an ACE inhibitor, or dose-reducing an SSRI can resolve symptoms without adding another prescription.

If the offending medication cannot be discontinued, the stepped-care algorithm from the table above applies: start with preservative-free tears, add an anti-inflammatory or tear-stimulating agent, and consider procedural interventions (punctal plugs, thermal pulsation) for refractory cases.

Managing Drug-Induced Dry Eye in Practice

A practical approach combines medication review with targeted ocular surface therapy.

Step 1: Audit the Medication List

Cross-reference every systemic medication against known drying agents. The American Academy of Ophthalmology Preferred Practice Pattern for DED specifically recommends documenting anticholinergic burden as part of the initial evaluation [16]. Patients rarely connect their allergy pill or blood pressure medication with their eye symptoms unless asked directly.

Step 2: Substitute or Reduce

When clinically feasible, switch to a less drying alternative within the same drug class. Loratadine has less anticholinergic effect than diphenhydramine. Nebivolol is less drying than timolol among beta-blockers. For acne patients on isotretinoin, discussing lower-dose protocols (0.25 to 0.5 mg/kg/day) with dermatology may preserve meibomian gland integrity while maintaining efficacy.

Step 3: Layer Ocular Surface Support

Start preservative-free artificial tears at least four times daily. If symptoms persist after 4 to 6 weeks, add cyclosporine or lifitegrast based on the inflammatory component. Patients with documented aqueous deficiency (Schirmer <5 mm) may benefit from adding varenicline nasal spray early.

Document the OSDI (Ocular Surface Disease Index) score at baseline and at 3-month intervals to track response. A change of 7.0 points or more on the OSDI is considered clinically meaningful per the original validation study [17].