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MattiSeppänen

Dry Eye Syndrome

Essentials

  • Dry eye syndrome is a disease of the eye surface with several possible underlying factors.
  • The causes are divided into two main types: excessive evaporation of tear fluid (90%) and decreased tear production (10%). In many cases, there are features of both types involved.
  • Dry eyes are often associated with allergy symptoms and vice versa.
  • In most cases, dryness of the eyes is mild. A GP should recognize severe disease that could cause permanent damage to the surface of the eye, and refer the patients to an ophthalmologist for further examination and treatment.
  • Essential diagnostic measures include fluorescein staining of the eye surface and ophthalmoscopy.
  • The Schirmer test and examining the persistence of the tear film (break-up time) will help to define the severity of dryness.
  • Treatment is based on regular and sufficient long-term use of moisturizing drops and protection from factors further drying the eyes.

Prevalence and causes

  • Dry eye is probably the most common eye disease.
  • Here are examples of factors causing dry eyes:
    • age: tear secretion diminishes with increasing age
    • gender: it is 2-3-fold more common in women than in men (hormonal factors and climacteric, in particular)
    • diseases and medication: see Table T1.

Diseases and drugs causing dry eyes

Skin disorders
Psoriasis
Atopy
Seborrhoeic dermatitis
Rosacea
Erythema multiforme
Ocular pemphigoid
Lyell's syndrome
Rheumatic diseases
Rheumatoid arthritis
Sarcoidosis
Sjögren's syndrome
Other diseases
Thyroid disorders (especially hyperthyroidism)
Inflammatory bowel diseases
Allergies
Diabetes
Amyloidoses (Meretoja disease)
Drugs
Dermatological drugs: isotretinoin
Antihypertensive drugs: beta blockers, diuretics
Psychotropic drugs: tricyclic antidepressants, benzodiazepines, MAO inhibitors
Parasympatholytics: atropine, scopolamine, antihistamines
Eye medication: glaucoma medication, such as beta blockers, brimonidine or apraclonidine; preservatives in eye drops
Other: some cancer drugs and hormones

Symptoms and findings

  • A dry, foreign body or gritty sensation in the eyes
  • Photophobia
  • Watering, itching and redness of the eyes
  • Variation of visual acuity
  • The symptoms are worse
    • in the morning (tear secretion is diminished at night)
    • in windy weather (drying effect)
    • in a smoky or dusty atmosphere (insufficient tears to protect the eye).
    • Many otherwise asymptomatic patients may have symptoms in an air-conditioned environment, e.g. at the workplace (= office eye syndrome; air flow causes evaporation).
  • The conjunctivae tend to become irritated and bloodshot (Picture 1).

Workup

  • Careful history taking is essential. Questionnaires (OSDI, DEQ-5) can be used, as necessary.
  • Fluorescein staining
    • Use preferably a fluorescein strip, so that the state of the cornea can be seen immediately under blue light.
    • A fluorescein drop can also be used but you then need to wait a few minutes for the drop to evaporate.
  • After fluorescein staining, the ocular surface should be examined under blue light through the magnifying lens of an ophthalmoscope.
    • Severe dry eye syndrome often appears as lower medial corneal abrasion.
  • The tear film break-up time (FBUT, fluorescein tear film break-up time) is measured in seconds.
    • Patients are asked to blink a few times and then keep their eyes open. The time the tear film remains unbroken is measured in seconds (tear film break-up time).
    • The normal FBUT is 15 s. A FBUT below 5 s suggests a severely dry eye. If the patient has corneal epithelial dystrophy, it can also reduce the persistence of the tear film.
  • The height of the tear meniscus collecting at the rim of the lower eyelid is assessed. A tear meniscus height of less than 0.3 mm suggests a severely dry eye.
  • A Schirmer test (see below) result below 10 mm signifies a moderately dry eye, a result below 5 mm a severely dry eye.

Schirmer test

  • The Schirmer test is performed using specially manufactured filter paper strips (Picture 2).
  • When looking for dry eye syndrome, the basal tear secretion is measured. The test is performed a couple of minutes after administering anaesthetic oxybuprocaine eye drops to prevent reflex lacrimation. The Schirmer test strip is bent at its notch to form a hook, and the strip is then hung on the lower eyelid margin at the border of the middle and outer thirds of the eyelid. The patient may keep the eyes open or closed.
  • After 5 minutes the strip is removed and the distance in millimetres from the notch to the end of the moistened area measured (Picture 3).

Differential diagnosis

Treatment

  • The aim of treatment is to minimize symptoms.
  • Known predisposing factors should be eliminated.
  • Non-pharmacological treatment
    • Sufficient breaks during reading and display screen work
    • Adjustment of air-conditioning (directing the air away from the face in the car and at the workplace)
    • Minimizing irritating environmental factors (dust, sauna bathing, tobacco smoke)
    • Regular warm bathing of the eyelid margin
    • Omega-3 supplements reduce inflammation and symptoms of dry eyes.
    • Use of protective goggles preventing evaporation
  • Pharmacotherapy
    • Regular long-term use of moisturizing eye drops and gels without preservative is the most essential form of treatment.
    • A mast cell stabilizer (sodium cromoglycate drops) can be added to the regimen, as necessary, particularly for atopic patients in the beginning of treatment.
    • Patients with severely dry eyes should be referred to an ophthalmologist, and treatment concentrates on treating the inflammation due to persistently dry eyes.
    • Drugs used under the supervision of an ophthalmologist
      • A mast cell stabilizer, 2-4 drops/day for long-term use, as necessary
      • Ciclosporine drops for long-term use (effects can often only be seen after 3 months of use); treatment often lasts at least 6 months.
      • Tacrolimus (0.03%) and pimecrolimus ointments
      • Oral doxycycline for the treatment of blepharitis, as necessary, for 6-12 weeks at a dose of 50-100 mg once daily. Doxycycline treatment is particularly considered if the patient has been diagnosed with rosacea.
    • If artificial tears and medication are not sufficiently effective and dry eye is caused by low tear secretion, consult an ophthalmologist to consider temporary blocking of the ducts through which tears drain (dissolvable punctal plugs).

References

  • Cote S, Zhang AC, Ahmadzai V et al. Intense pulsed light (IPL) therapy for the treatment of meibomian gland dysfunction. Cochrane Database Syst Rev 2020;(3):CD013559. [PubMed]
  • Downie LE, Ng SM, Lindsley KB et al. Omega-3 and omega-6 polyunsaturated fatty acids for dry eye disease. Cochrane Database Syst Rev 2019;(12):CD011016. [PubMed]
  • de Paiva CS, Pflugfelder SC, Ng SM et al. Topical cyclosporine A therapy for dry eye syndrome. Cochrane Database Syst Rev 2019;(9):CD010051. [PubMed]
  • Ervin AM, Law A, Pucker AD. Punctal occlusion for dry eye syndrome. Cochrane Database Syst Rev 2017;(6):CD006775. [PubMed]
  • Pan Q, Angelina A, Marrone M et al. Autologous serum eye drops for dry eye. Cochrane Database Syst Rev 2017;(2):CD009327. [PubMed]
  • Pucker AD, Ng SM, Nichols JJ. Over the counter (OTC) artificial tear drops for dry eye syndrome. Cochrane Database Syst Rev 2016;(2):CD009729. [PubMed]