Caroline_Christie_-_CET_dry_eye

CET Continuing education

T

ype the term ‘dry eye’ into Google and the result is about 32,000,000 hits ranging from comprehensive overviews of symptoms, diagnosis and management to chat groups, support groups and blogs. Companies manufacturing pharmaceuticals, over-the-counter artificial tear preparations and other treatment devices have entire websites dedicated to dry eye.

It is, however, well within the clinical competencies of both optometrists and contact lens practitioners to manage ‘dry eye’ and in most instances these patients do not require to be referred to the GP/ ophthalmologist nor should the practice watch sales of products related to dry eye management be lost to pharmacies and the internet.

As a disease, dry eye is complex.

Modern research and understanding has shown that we simply can’t view dry eye as a failure of tear quantity or quality, but recognise it as a complex ocular surface disease.

The Dry Eye Workshop (DEWS)1 forum is composed of an international panel of dry eye experts tasked to update our understanding of dry eye. The panel has released several papers on definition and classification, diagnosis, epidemiology, treatment and management, and research.

A fundamental change in our understanding of dry eye is evident in its current definition: ‘Dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear instability with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear and inflammation of the ocular surface.’

How does this definition apply to us in a clinical setting today?

The new definition has done a great deal to show that dry eye is not a simple problem with a simple solution. Indeed, the clinical picture for a patient can change as a result of any and all of the factors that go into producing dry eye initially. A previously happy patient living in a cool, humid environment may increase the amount of computer based work in an air conditioned office while starting a course of medication for increased blood pressure. Should any of us then be surprised to find out that this patient had quickly become a dry eye ‘victim’ and subsequently unhappy?

The key point is that a patient’s clinical picture can change as lifestyle 30 | Optician | 25.11.11

Practical guide to dry eye management Caroline Christie explains how best to assess and manage the dry eye. Module C17953, one specialist point for CLOs and one general CET point for optometrists and DOs Subjective Evaluation of Symptoms of Dryness (SESoD) Evaluate your ocular discomfort due to the symptoms of dryness on a scale of 0 (none) to 4 (severe).

You may use the following descriptions to assist in your score Dryness

Grade

Description

None

0

I do not have this symptom

Trace

1

I seldom notice this symptom, and it does not make me uncomfortable

Mild

2

I sometimes notice this symptom. It does make me uncomfortable, but it does not interfere with my activities

Moderate

3

I frequently notice this symptom, it does make me uncomfortable, but it sometimes interferes with my activities

Severe

4

I always notice this symptom. It does make me uncomfortable, and it usually interferes with my activities

Trefford Simpson and colleagues2 recently assessed four commonly used questionnaires McMonnies, DEQ, Ocular Surface Disease Index (OSDI) and Subjective Evaluation of Symptom of Dryness (SESoD) – found overall scores highly correlated – concluded use of a quick three-question screening tool is ideal for routine clinical practice.

Key questions (1) Frequency of symptoms (2) Presence of discomfort (3) Interference with activity

Figure 1 Dry eye grading scale

and environments change. However, we rarely see our patients for more than 15-20 minutes when collecting their contact lenses or 30 minutes over the course of an entire year, in the case of annual eye examinations.

How then can we possibly expect to correctly identify a patient’s problem and confidently recommend a management approach? Often our recommendations are not followed through, leading to similar or even increased symptoms by the time of the next appointment.

Optimal management of dry eye requires careful listening to the patient’s history and symptoms, gleaning information about their work and recreational environment, a detailed assessment of the tears and ocular surface using a battery of tests and an appreciation of the numerous management approaches that exist.

The first step is to properly identify dry eye sufferers. Most dry eye patients have symptoms, but they are not always reported with the chief complaint or reason for visiting the practice. Therefore, it is valuable to conduct a symptom survey (dry eye questionnaire) to help

identify and categorise the presence and more importantly the severity of dry eye among patients. A good questionnaire will bring problems to your attention and help you ask the right sort of probing questions. I then want to hear patients describe how their eyes feel in their own words, which can then lead into a more detailed informative conversation.

What time of the day does the problem occur? Have you ever tried anything to deal with this? If so, what? What, if any, activities does it affect, computer work, reading, driving and so on?

The DEWS report does not specify how we should routinely ask patients about symptoms but does indicate several important components to symptom assessment: ● Frequency – how often a symptom is expressed ● Severity – how bad or disabling the symptom is ● Interference with activity – how it affects specific work/home based tasks.

It is now believed that in the early stages of dry eye disease symptoms are not present all of the time but are episodic in nature and could be influenced by

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Continuing education CET The type of blink required for optimum blink efficiency has the following characteristics:

● An efficient blink is full and complete, meaning that the top lid lightly touches the bottom lid ●A n efficient blink is relaxed and light, meaning that only the muscles of the eye are involved.

Specifically, the muscles of the eyebrows and cheeks are not involved

● An efficient blink is quick and rapid, taking only one third of a second to complete ● Finally, an efficient blink looks confident and natural Figure 2 Extract from a blink exercise sheet3

environmental factors including the growing use of visual display devices and exposure to air conditioning/central heating at work and in the home.

How disabling a symptom may be is likely dependent on the individual.

Some patients have a higher tolerance for ocular irritation compared to others.

Other patients may stop or avoid certain activities but may not consider this to be related to how their eyes feel.

Asking patients specific questions about how eye irritation or discomfort may prevent them or reduce their ability to perform certain activities, such as reading or using a computer, can help in determining the impact of symptoms.

The impact of the symptoms may be recorded by reference to a grading scale (Figure 1).

Specific questions about length of comfortable computer use in hours can help track changes over time with or without treatment.

Blink rate Given that evaporative dry eye is the most common form of tear deficiency seen in routine optometric practice, failure to consider the need to improve blink efficiency may significantly undermine efforts to improve tear function in general.

The normal apposition of the lids during a complete blink promotes lipid secretion from the meibomian glands.

The lipid layer is spread across the cornea by the upper lids and inefficient blinking may be associated with poor maintenance of lipid layer integrity. For example, during prolonged reading, when blink rate and blink completeness are significantly reduced, the lipid layer can thin and virtually disappear before reappearing with conscious blinking.

It is possible that reduced lipid flow associated with inefficient blinking contributes to stasis and gland blockage.

In addition, lipid flow from glands that have been unblocked with warm compresses, lid massage and cleansing may not maintain their patency and so elapse to a blocked state if blink inefficiency is not remediated.

Apart from the potential to contribute to reduced lipid flow, incomplete blinking effectively doubles the inter-blink interval

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and increases the potential for increased tear layer loss by evaporation from the areas of conjunctiva and cornea which are exposed by an incomplete blink.

Although deliberate, forceful blinks promote secretion from unobstructed glands, they have a tendency to produce debris in the tear film leading to transient blurring. Patients will prefer not to blink rather than depend on conscious forceful blinking episodes. It may be better to try to achieve longer lasting benefits from improved unconscious blink efficiency.

Figure 2 shows a blink instruction sheet.

Failure to address blink efficiency where a need is indicated may have greater significance with computer use and/or with other forms of reading and close vision demands. Such activities are associated with reduced blink efficiency and this may be exacerbated with concurrent exposure to central heating or air conditioning.

At present, there is no single ‘gold standard’ test for developing a clinical diagnosis of dry eye; therefore, a battery of tests is generally employed in clinical practice (as well as for research purposes) to define ‘dry eye’.

Remember, however, to always carry out the least invasive tests first as you want to minimise the disruption to the tear film if you are attempting to measure and monitor changes to factors such as the tear quantity, quality and stability (Table 1). Ideally carry out the tests in the same order, under the same conditions and where possible the same time of day at each visit to aid comparison of results to make better informed decisions on ongoing management plans.

Dry eye evaluation must also be multifaceted. In addition to assessing tear volume, quality, and stability, it is necessary to interpret staining patterns and complete a full lid evaluation to rule out the presence or co-existence of blepharitis. There is overlap of many symptoms of dry eye disease and blepharitis, so careful clinical evaluation is important.

Meibomian gland dysfunction (MGD) The International Workshop on Meibomian Gland Dysfunction report

revealed that MGD may actually comprise the majority of dry eye disease.

DEWS: ‘Meibomian gland dysfunction (MGD) is a chronic, diffuse abnormality of the meibomian glands commonly characterised by terminal duct obstruction and/or qualitative/quantitative changes in glandular secretion.’4 In MGD, the meibomian glands are frequently obstructed, affecting the volume and quality of the oily secretions.

The result is tear film instability, which can lead to ocular surface damage and inflammation, and, commonly, to symptoms.

However, despite the frequency of presentation, MGD remains relatively poorly managed in clinical practice. The chronic nature of the condition requires that therapy be applied regularly, and with long-term commitment. Management of MGD typically includes warm compresses, massage and lid ‘scrubs’ known to improve lipid layer thickness and, in turn, reduce tear evaporation.

The goal of MGD management is two-fold: ● To assist the remaining meibomian glands in producing more and better quality lipids ● To reduce inflammation of the glands, this is nearly always present.

Warm compresses and eyelid massage. The ‘warmth’ helps to overcome the elevated melting point of lipids inspissated within the glands. It is important to note that although many text books suggest the use of warm flannels, they rarely reach or indeed maintain the temperature required to melt these inspissated lipids and repeated removal and reheating of the flannel is required. There are, however, a number of commercially available devices from the simple and inexpensive MGDRx EyeBag and iHeat devices through to 25.11.11 | Optician | 31

CET Continuing education

Figure 3 Lissamine staining of the conjunctiva

more sophisticated moist heat devices such as Blephasteam goggles which achieve the 39-40°C required to melt the meibum while maintaining a constant heat over the treatment period of 10-15 minutes.

Following the heat phase, firm digital massage of the lid margin helps to express the oils, so that the glands become unblocked. Eyelid massage also encourages blood flow to the eyelid area containing the glands, which can help remove inflammatory mediators.

Finally, cleaning of the lid margin to remove excess oils and dead cells is best done not with dilute baby shampoo but with specifically designed commercial solutions and wipes that are free from preservative, fragrance and alcohol.

Baby shampoo contains surfactants and when in contact with the tear film will contribute to destabilising the lipid layer, detracting from the initial aim of the entire lid hygiene exercise in providing a thicker and more stable lid layer to prevent/reduce evaporation of the tear film and improve symptoms of dry eye.

Lipid replacement artificial tears.

These products replace/supplement the missing lipids that should normally be secreted by the meibomian glands.

While direct evidence is limited, lipid replacement drops should reduce the evaporation rate and should provide symptomatic relief and help to protect and possibly heal the ocular surface. They also wash out inflammatory cytokines to provide a thicker, more stable tear film, which reduces the inflammatory stimulus.

Dietary supplements/omega-3 fatty acids. The metabolites of both omega-6 and omega-3 essential fatty acids (EFAs) are anti-inflammatory when the dietary ratio is 4:1. The typical North American diet (nowadays often similar in the UK) is closer to 15:1 causing the derivatives of the omega-6 EFAs to contribute to the inflammatory process.

32 | Optician | 25.11.11

Figure 4 Fluorescein tear break-up

Omega-3 FA supplements should not be considered if the patient is using a blood thinner and/or serum lipid-lowering drugs. Consult with the patient’s GP prior to starting any supplements. It may take 1-2 months of regular use before any effect is noticed.

Refer to GP for systemic tetracycline derivatives. The tetracycline derivatives are anti-inflammatory in action and when inflammation is reduced the Table 1 Dry eye work-up ● Dry eye questionnaire (record score) ● Measure tear film osmolarity (if equipment

available)

● Keratometer/topographer

– NIBUT

– Tear quality and meniscus height

– Tear quantity

● Tearscope (currently out of production) ● Slit lamp ● Phenol red threads (if available) ● Slit lamp

– Grade conjunctival hyperaemia – Insert lissamine green ● Record/grade – conjunctival stain (Figure 3)

– Insert FL ● Observe tear mixing ● TBUT (Figures 4 and 5) ● Record/grade corneal staining (Figures 6 and 7)

– Evert lid ● Record/grade - Lid wiper epitheliopathy

– Examine lid margin ● Check meibomian gland patency (Figure 8) ● Discuss thoroughly your findings

– If they understand why they are doing things

they are more likely to do them! ● Create a personalised management plan

– Write it down in clear simple steps

– Demonstrate procedures and products

– Prescribe and sell products ● Don’t try too much too soon

– Compliance will be poor and you won’t know

the effect of each therapy ● Arrange suitable follow up appointment in 2-4 weeks

Figure 5 Tear break-up with superficial staining

glands can secrete more and better quality lipids. Therapy may need to be continued for 3-6 months in cases in which inflammation is not subsiding and/or symptoms are not improving.

Artificial tears Artificial tears are the first line therapy in patients with dry eye. However, a significant number of practitioners offer artificial tears as the only solution (treatment plan) to patients complaining of dry eye symptoms.

Two particular statements published in the DEWS report1 worth considering are: ● ‘For patients with moderate to severe dry eye disease, the absence of preservatives is of more critical importance than the particular polymeric agent used in ocular lubricants’ ● ‘For patients with dry eyes even vanishing preservatives may not totally degrade due to the decrease in tear volume and may be irritating.’

This has changed my approach somewhat and I now more than ever recommend non-preserved artificial tears to my dry eye patients, irrespective of the number of times they insert the drops or whether they are a contact lens patient or not. Optician will be publishing a comprehensive table of currently available ocular lubricants in the UK next week. Once the disease process is actively managed, artificial tears still play a role as supportive therapy to alleviate symptoms.

Patient education So, how do we educate our patients?

What is the best way to ensure that they are going to remember what was said in the practice?

It all starts with appropriate verbal communication. Make sure that your descriptive language is easy to understand.

If the message is too scientific it may not register and all your hard work would have been in vain. Supplement verbal

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Continuing education CET

Figure 6 Inferior dessication staining

instructions with brochures or links to websites where patients can get accurate information.

Design a treatment plan, emphasise the importance of adhering to this plan and schedule a follow-up visit in 3-4 weeks. This gives the patient time to form the habit of using the drops or performing the lid hygiene routine but does not give them time hopefully to fall off the wagon or run out of the product you advised.

Nowadays, patients can find out anything they want on the web, so it is

Figure 7 Staining pattern related to poor blink

Figure 8 Checking the meibomian gland patency

Multiple-choice questions – take part at opticianonline.net

1

According to the Dry Eye Workshop Report (DEWS), which of the following is NOT TRUE of dry eye?

A There is a decreased osmolarity of the tear film B There is potential for damage to the ocular surface C Symptoms include discomfort and visual disturbance D Dry eye is a multifactorial disease

2

What are the three key question areas required to ascertain the grade for the level of dryness?

A Frequency, presence of discomfort and blurred vision B Frequency, presence of discomfort and interference with activity C Frequency, presence of discomfort and discharge D Presence of discomfort, blurred vision and discharge

4

Which of the following is not a symptom of MGD? A Burning sensation B Blurred vision C Discomfort D Itching

5

For patients with moderate to severe dry eyes, what should be avoided when selecting a dry eye product?

A High viscosity polymers B Hypotonic agents C Preservatives D Electrolytes

6

What is the optimal temperature for a lid warming device to reach and maintain to melt inspissated meibum from the lid margin?

A 25°C B 37°C C 40°C D 50°C

3

Which of the following is NOT TRUE of an ideal blink pattern?

A Full and complete B Relaxed and light C Slow and precise D Confident and natural Successful participation in this module counts as one credit towards the GOC CET scheme administered by Vantage and one towards the Association of Optometrists Ireland’s scheme.

Deadline for responses is December 22 2011

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even more critical that their practitioner leads them in the proper direction to informative sites rather than leave them to Google poorly referenced or, worse still, pure ‘selling’ sites.

A dedicated member of staff, ‘the optical hygienist’ trained in dealing with dry eye management – the insertion of drops, lid hygiene techniques and associated products – is a major asset to the practice both in time management and patient improved compliance and satisfaction.

Ensure that the patient understands that this is a dynamic process and that the required management may change as mentioned at the beginning of this article. They need to understand what to do if circumstances worsen and symptoms return.

In summary, dry eye disease is commonly encountered in everyday practice. We must use a thorough case history of symptoms in conjunction with a variety of clinical and diagnostic tests to diagnose the condition and its severity. Approach management and treatment options in a systematic way based on symptoms and clinical signs of severity Dry eye is a chronic disease and one that can be frustrating for both patient and practitioner. In our ‘quick fix’ society, this is one disease process that does not play by those rules. ● References 1 The Dry Eye Workshop (DEWS). The Ocular Surface; April 2007, Vol 5, No 2.

2 Simpson et al. Dry Eye Symptoms Assessed

by Four Questionnaires. OVS, 2008; 85:8 692-698.

3 McMonnies CW, Incomplete Blinking, Contact Lens & Anterior Eye, 30 (2007) 37-51.

4 Nicholls K et al. International Workshop on MGD. Invest Ophthalmol Vis Sci; March 30, 2011 vol 52 no 4 1917-1921.

● Caroline Christie is associate director for contact lens teaching, City University 25.11.11 | Optician | 33