The DEWS Report emphasises that it is important to adopt a logical stepwise approach to grading the severity of dry eye in an effort to determine appropriately staged prescribing and management. But what do we know about dry eye and what have we learned about dry eye since the 2007 Dry Eye Workshop (DEWS) Report was first published?
Dry eye causes are multifactorial, and the severity of dry eye can be accurately graded by putting due consideration into both patient symptoms and clinical signs. We can thus determine a severity level and prescribe appropriate management tailored to address each fundamental cause.
Level One Dry Eye
- Mild to minimal ocular symptoms
- Mild or minimal ocular signs such as conjunctival injection, conjunctival staining, and corneal staining
- Tear volume normal
- MGD status variable
- TFBUT and Schirmer results may appear normal (10-15seconds)
Level One Management
- Education and environmental/dietary modifications
- Elimination of offending systemic medications
- Artificial tear supplements, gels and ointments
- Eyelid therapy
When explaining dry eye disease, patients will usually gain a reasonable understanding of their condition, however most will follow only some of the prescribed treatments.
Patients are more motivated to address all causes and follow all recommended treatments when they understand the overall mechanism of how the eye works in remoisturising the ocular surface.
liposomal sprays compare favourably against lubricating drops in reducing clinical signs of dry eye…
Environmental and Dietary Modifications
Environmental modifications to reduce or avoid exposure to known triggers may reduce dry eye symptoms.
Also helpful is prescribing prophylactic measures to your patient for prelubricating before entering environmental situations that will usually trigger dry eye symptoms.
A key measure is ensuring sufficient omega-3 in the dry eye patient’s diet. The typical western diet has 20–25 times more omega-6 than omega-3, and omega-6 is a precursor for Arachidonic acid and other proinflammatory lipid mediators. Omega-3 is essential for the opposite effect, as it causes an inhibitory effect of these mediators.1
Dietary modifications include changing medication that may induce adverse effects of dryness. Common culprits are the anticholinergics such as the antihistamines and antidepressants.
Elimination of any eyedrops that may contain preservatives may also make a considerable difference.
Artificial Tear Substitutes, Gels and Ointments
Lubrication of the ocular surface can reduce the symptoms for dry eye development, and potentially reduce its subsequent inflammatory effects by diluting the hyperosmolarity of the ocular tear film. This reduces subsequent damage to the ocular surface.
A few large scale studies show some lubricants perform better than others.2 Theratears for example mimics the electrolyte composition of human tears. Systane drops contain the gel-like HP-Guar that demonstrates preferential binding to the more hydrophobic, desiccated or damaged areas of the surface epithelial cells.
Systane lubricating drops and Optrex liposomal sprays both contain lubricating and lipid components.3 It has been established that an increased thickness in the lipid layer contributes significantly to tear film stability, demonstrated in the Systane lubricating drops and Optrex liposomal sprays.
Recent studies show that liposomal sprays compare favourably against lubricating drops in reducing clinical signs of dry eye such as staining with lid parallel conjunctival folds (LIPCOF), lid margin inflammation and improvements in invasive tear break up time (TBUT).4–8
Eyelid therapy comprises two parts, firstly, treatment for anterior blepharitis by anti-inflammatory interventions such as lid cleansing wipes or cleansing foams and secondly, meibomian gland dysfunction (MGD). MGD is implicated in 80 per cent of dry eye cases, so eyelid therapy to address posterior blepharitis and MGD comprises hot compresses and meibomian gland expression.
People with MGD related dry eye have increasingly thicker, waxier meibum that is harder to express. The worse the severity of MGD, the less improvement they see with an at home regimen of hot compresses.
In office therapy for meibomian gland expression can be easily introduced in general optometric practice. A Blephasteam device, for example, can deliver more consistent heat compared to a hot compress thus improving compliance, followed by manual meibomian gland expression.
Level Two Dry Eye
- Moderate ocular symptoms
- Moderate ocular signs of conjunctival injection, conjunctival staining but no corneal staining
- Reduced tear volume, slight debris appearing in tear film
- MGD status variable
- TFBUT and Schirmer results 10 seconds or less
Level Two Management
If level one treatment is inadequate for the management of symptoms, the addition of management guidelines for level two is required:
- Tetracyclines (for meibomianitis and rosacea)
- Punctal plugs
- Moisture chamber spectacles
There are a range of studied topical steroid concentrations discussed in DEWS, but a good ‘proposed recipe’ finding success with practitioners would be prescribing the topical non preserved corticosteroid prednisolone 0.5 per cent minims for two weeks for four times a day with an appropriate taper, provided any contraindications have been excluded, including any active ocular infection, particularly epithelial herpetic simplex keratitis, and pregnant or breastfeeding mothers. Although adverse effects are somewhat rare and have only been reported from prolonged usage, the risk for posterior subcapsular cataract development, ocular hypertension and glaucoma should be considered.9
In moderate to severe dry eye, topical cyclosporine-A concentrations found to be most appropriate were 0.05 per cent and 0.1 per cent. For recalcitrant cases there have been favourable reports for concurrently prescribing both corticosteroids and cyclosporine-A.
Intensive application with an appropriate lubricant is essential to ensure the tear film has sufficient lipid and aqueous components.
Cessation of symptoms may occur when prescribing these interventions, but recur in future. Re-prescribing these as a pulse dose added to the patient’s normal dry eye regimen should be considered when required.
Secretagogues are topical pharmacological agents that increase production of aqueous and mucous secretion to contribute to the ocular tear film, such as diquafosol tetrasodium, hydroxyeicosatetraenoic acid, rebamipide, gefarnate, ecabet sodium and 15(S)-HETE.9 These are not commonly encountered in general optometry practice but studies show some promise in their effectiveness.
Oral tetracycline derivatives, such as minocycline and doxycycline, have desirable anti-bacterial and antimicrobial effects that are also well established for their use in dry eye management.10–12 The mechanism of action for tetracycline derivatives appears to be because they are antimicrobials, thus they decrease the bacterial flora that produce the enzymes that break down lipids and also inhibit lipase production.13 In doing so they are thought to contribute to higher lipid levels in the ocular tear film. Tetracyclines also inhibit matrix metalloproteinase (MMP) expression, particularly MMP-9, a cytokine that is a known proinflammatory cellular mediator in elevated levels in those with dry eye. Dry eye related to ocular rosacea is particularly responsive to doxycycline.14,15
Punctal plugs can be very beneficial in certain circumstances, because they can reduce tear clearance and increase tear volume for a wide range of aqueous deficient dry eye groups. This is particularly appropriate once any active ocular surface inflammation has been resolved.
Moisture Chamber Spectacles
The most rational theory behind the effectiveness of moisture chamber spectacles has been proposed by Korb et al. around increasing periocular humidity to increase the lipid layer in the ocular tear film, so these can be helpful for those at a level with moderate to severe dry eye.1
Level Three Dry Eye
- Severe ocular symptoms
- Severe signs of conjunctival staining and severe conjunctival injection
- Corneal staining present
- Tear film filamentary keratitis and mucus clumps in tear film
- MGD involvement
- TFBUT five seconds or less and Schirmer test 5mm/min or less.
Level Three Management
If level two treatment is inadequate for the management of symptoms, the addition of management guidelines for level three is required:
- Serum – autologous serum
- Contact lenses
- Permanent punctal occlusion.
Level Four Dry Eye
- Severe and disabling ocular symptomS
- Severe signs of conjunctival staining and conjunctival hyperemia
- Corneal staining present in the form of severe SPK
- Tear film shows filamentary keratitis and mucus clumps in tear film
- MGD involvement but now severe enough to cause remodeling of the lid margins, such as keratinisation of the lid margins, symblepharon and trichiasis
- TFBUT zero seconds and Schirmer test 2mm/min or less.
Level Four Management
If level three treatment is inadequate for the management of symptoms, the addition of management guidelines for level four is required:
- Systemic anti-inflammatory medications
- Surgery-tarsorraphy, amniotic membrane transplant, salivary gland transplant, or mucus membrane surgery.
IPL and Lipiflow
Intense Pulse Light therapy (IPL) and Lipiflow therapy is worth mentioning, and whilst Lipiflow has been available now for a few years and has received mixed feedback from patients for dry eye treatment, recent double masked studies presented by Associate Professor Jennifer Craig on IPL show promising results in dry eye cases with symptomatic MGD. IPL is worthwhile discussing, but beyond the scope of this article on dry eye management in the general optometric practice.
Heading Back to the Future
The DEWS Report was published in 2007 and has provided us with an excellent guide to management and a treatment strategy based on stages to match the level of classification of severity.
The Tear Film and Ocular Surface Society has started work on the DEWS Report II, an assessment of current research, expansion of emerging treatment and update on findings that have come out since the first DEWS. The steering committee plans to start mid 2015 to critically assess the etiology, mechanism, distribution and global impact of dry eye, and provide an update on management and therapy. There is talk the very definition of dry eye as we know it will also be fundamentally changed.16
Margaret Lam BOptom UNSW, OA, CCLSA, OSO, IAO graduated from the University of New South Wales in 2001. A principal of theeyecarecompany she practises full scope optometry and has extensive experience in specialty contact lens fitting in corneal ectasia, keratoconus and orthokeratology.
Ms. Lam has been a past recipient of the Neville Fulthorpe Award for Clinical Excellence. She currently serves as the State President of the Cornea and Contact Lens Society of Australia for NSW (CCLSA).
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