Dry Eye Disease Quiz

PHAR 1051 Miscellaneous Eye Topics

• The course covers miscellaneous eye topics including dry eye, eyelid conditions, and ocular surgery.
• Learning objectives include recognizing signs, symptoms, and predisposing factors for dry eyes, blepharitis, hordeolum, and chalazion.
• Students should be able to provide non-prescription recommendations for various eye conditions.
• Knowledge of prescription drugs, their roles, appropriate use, adverse effects, contraindications, and precautions is essential.
• Students should have the ability to provide advice on non-pharmacological treatment and prevention of these conditions.
• Recognize red flags for referral to physicians.
• Knowledge of post-cataract surgery medications is expected.

Dry Eye Disease

• Dry eye disease (DED) is a multifactorial disorder of the ocular surface, characterized by tear film instability, hyperosmolarity, inflammation, damage, and neurosensory abnormalities.
• Dry eye may be aqueous-deficient or evaporative.
• These types of dry eye involve overlapping mechanisms.

Anatomy of the Tear Film

• The tear film has three layers: mucous, aqueous, and lipid.
• The mucous layer is produced by goblet cells and lubricates the eyelids and the eyeball.
• The aqueous layer comes from the lacrimal glands and hydrates the mucous layer, provides oxygen and electrolytes, and protects against bacteria.
• The lipid layer, produced by meibomian glands, prevents tear evaporation and stabilizes the tear film.

Pathophysiology of Dry Eye

• The pathophysiology of dry eye (DED) is complex and involves environmental factors, lacrimal secretion, tear hyperosmolarity, tear film instability, and surface stress.
• Possible causes include low humidity, high wind speed, high temperature, low tear flow, and surface stress causing damage to the surface of the eye.

Risk Factors for Dry Eye

• Age, particularly in females, increases DED risk.
• Decreased blinking, frequent computer use, medical conditions (Parkinson's disease, hyperthyroidism), and contact lens wear are risk factors.
• Environmental factors, such as low humidity, high temperatures, and air pollution can also contribute to DED.
• Specific medications, such as anticholinergics, amiodarone, and antiandrogens, can contribute to DED.
• Surgery, particularly cataract surgery, laser eye surgery, etc., can increase the risk of DED.

Clinical Presentation of Dry Eye

• Common presentations include foreign body sensation, itchy, burning, tired eyes, and bilateral eye involvement. Other symptoms may include photophobia, blurred vision, or redness.
• Refer patients to a physician if ocular pain is present, if there is trauma to the eye, exposure to chemicals, or heat, a foreign body is present, vision changes, or if a patient is a contact lens wearer.

Ruling Out Red Flags for Dry Eye

• Possible red flags include contact lens use, chemical exposure, injury or trauma, visual disturbance, photophobia, pain, and prior history of ocular diseases.
• Patients may present with multiple red flags.

Non-Pharmacological Management of Dry Eye

• Smoking cessation, limiting screen time, use of cool compresses, and humidifiers can help manage dry eye.
• Ski/swim goggles with moist gauze inside, moisture chamber spectacles, and punctal plugs can prevent dry eye.

Pharmacological Management of Dry Eye

• Tear replacement with ocular lubricants is a mainstay of dry eye therapy (first-line treatment)
• Over-the-counter (OTC) products, often termed "artificial tears", attempt to replace or supplement natural tear film.
• Artificial tears primarily address symptoms rather than the underlying pathophysiology.

Ocular Lubricants (Artificial Tears)

• OTC ocular lubricants (artificial tears) are available as liquids, gels, or ointments.
• They are generally safe and contain ingredients such as preservatives, electrolytes, and lipids.
• Preservative-free formulations are beneficial, especially in patients with severe disease, and may help reduce adverse effects. Some products contain less-toxic preservatives such as Polyquad, sodium chlorite, and sodium perborate.
• Osmolarity is an important aspect as hypo-osmolar tears may assist in countering the increased tear osmolarity of DED.
• Osmolarity can be controlled and adjusted by adding/removing electrolytes to prevent or manage inflammation.
• Viscosity (thickness) and lipids are also important aspects in managing tear film function.

Preservatives in Ocular Lubricants

• Preservatives are typically necessary in multidose products to prevent contamination.
• Benzalkonium chloride is a common preservative but has associated toxicity.
• Less toxic preservatives that can be used include polyquad, sodium chlorite, and sodium perborate.

Ideal Characteristics of Tear Film

• Electrolytes such as potassium and bicarbonate are important for maintaining corneal thickness and epithelial barrier function.
• The osmolarity of tears should be considered. Hypo-osmolar tears may offset the effects of elevated osmolarity as a result of DED. Osmolarity should be reduced or avoided when possible.
• Ideally, tear osmolarity should be between 290-308 mOsm/L
• Viscosity is important to aid tear retention.
• Lipids are needed to prevent evaporation.

Specific DED Treatment Options (Ophthalmic/Systemic)

• Immunomodulators, like cyclosporine, reduce inflammation and may improve tear production and quality.
• Corticosteroids, such as fluorometholone and loteprednol, are used short-term to reduce inflammation.
• Oral secretagogues, such as pilocarpine, may benefit patients with Sjögren syndrome.
• Omega-3 fatty acids might influence meibomian gland function, but additional studies are needed.

Eyelid Conditions

• Hordeolum (sty): An acute bacterial infection of eyelid glands (Zeis or Moll)
• Chalazion: A chronic sterile inflammation of a meibomian gland.
• Blepharitis: A chronic condition characterized by inflammation of the eyelid margins. Includes anterior and posterior involvement.

Ocular Surgery

• Cataracts are a leading cause of vision loss in older adults.
• Cataract surgery involves removing the clouded lens and replacing it with an artificial lens.
• Post-operative management typically involves topical antibiotics, corticosteroids, NSAIDs, and analgesic, and patient education.
• Monitoring of the patient following surgery is important to follow up on complications such as endophthalmitis.