Dry Eye in Myopia Management

Dry eye is a common complaint in general optometry, and can occur in children too. How could dry eye in kids influence myopia management?

Whilst far less likely than their adult counterparts to suffer from dry eye, children and teenagers can still have problems with dryness which can challenge contact lens (CL) wear.¹ A survey of both CL and non-CL wearers found that 19% of respondents younger than 20 had dry eye symptoms - a high proportion, despite the higher 30% of symptomatic respondents over age 20.² When CL wearers were specifically surveyed, only a small 4% of children suffered symptoms compared to 56% of adults. So why are children reporting less dry eye symptoms?

The majority of myopia control CLs are daily disposable, which may have reduced deposits and increased oxygen transmission compared to reusable CLs.¹ Large scale CL studies on adults, however, have found no difference in the dry eye symptoms reported between monthly and daily CL wearers.³ Children naturally produce more tear volume, and these tears have more mucus and a lower lipid component than an adult tear film.¹ This may lead to even fewer deposits and discomfort during lens wear, reducing symptoms.

Another explanation is the simple resilience of children. Research has indicated that children report less symptoms than adults with the same ocular signs of dry eye.⁴  This could be due to less experience and potentially less language to explain or describe discomfort. We also know that dry eye symptoms increase over years of lens wear, and motivation to persist can decrease with time. Children by factor of youth will be new to lens wear, and potentially more motivated to continue. A key point here is just because they aren't talking about it doesn't mean it isn't happening - specifically ask your young patients about their lens comfort and intervene when symptoms and signs deem it necessary.

Allergy wields a double-edged sword to CL wear because not only does allergy induce ocular dryness, itchiness and discomfort but antihistamines, due to their anticholinergic side effects, can exacerbate dry eye symptoms. Allergy is a significant problem in our youth - 10% of children have some form of hayfever; with almost all of them having ocular symptoms.⁵ Atopic CL wearers are far more likely to have dry eye symptoms (58% compared to 33%, in adult studies),⁶ and are much more likely to be intolerant to full time CL wear which can present a significant challenge to myopia controlling CL wear. On the flip side, CL wear can actually help symptoms of ocular allergy - in one small study, a lubricant enhanced daily disposable CL offered a type of ‘barrier’ to airborne pollens and other antigens, reducing symptoms of burning and stinging. Clinical signs of bulbar hyperaemia, corneal and conjunctival staining, and palpebral conjunctival roughness were reduced by standard daily disposable (DD) wear, while limbal and palpebral conjunctival redness was further reduced in the enhanced lubrication DD.⁷

Medications prescribed to children and teenagers which are known for dry eye side effects include anti-depressants, anti-anxiety, antihistamines and those to combat cystic acne.

Tricyclic (TCA) and selective serotonin reuptake inhibitor (SSRI) antidepressant medications are well understood to produce anticholinergic side effects and cause dry eyes.⁸ The commonly prescribed anti-acne medication Accutane is a derivative of vitamin A that reduces oil production and subsequently can cause significant meibomian gland dysfunction and difficulty with contact lens wear.9

Children and teens taking these medications are likely to need ocular lubricants as part of their routine care, regardless of whether they wear contact lenses or not.

Binocular vision (BV) disorders and dry eye symptoms may also be linked - one study found that young adult myopes with contact lens dry eye symptoms showed a stronger correlation between their Convergence Insufficiency Syndrome Survey (CISS) and Ocular Surface Disease Index (OSDI) survey scores than between their OSDI scores and ocular signs. Almost half of them exhibited an accommodative lag of more than 1D in single vision CL wear. This led the authors to conclude that symptomatic BV disorders could be mistaken for dry eye disease.¹⁰

It's important to ensure symptoms of dryness are not being confused with asthenopia - if the contact lens fit is perfect, and lubricants help but the problem persists, consider sources of asthenopia. For help on assessing and managing BV, check out our Expand my clinical skills portal and our accredited online course Binocular Vison Fundamentals.

Even though children are less likely to experience and report dry eye symptoms than their adult counterparts, smartphone usage is a significant risk factor for developing paediatric dry eye disease (DED). A study on 916 children aged 6-11 years in Korea surveyed time spent on technology, undertook the Ocular Surface Disease Index (OSDI) questionnaire and conducted slit lamp examination on all participants. Diagnosis of DED was based on International Dry Eye Workshop classifications. Almost 2.5 more hours per day was spent on smartphones in children with DED, and four weeks of smartphone cessation improved signs and symptoms. Interestingly, there was no relationship found between total learning or television watching time and DED, however those with higher outdoor time had far less DED.¹¹

As mentioned above, children are less likely to suffer dry eye symptoms for a variety of reasons, so are likely to be highly satisfied CL wearers. Predisposing factors should be considered but may not preclude from CL wear - keeping in mind that daily disposable contact lenses can improve comfort in patients with ocular allergy,⁷ where traditionally this would have been considered a contraindication for CL wear.

Orthokeratology (OK) may be a good option for children whose dry eye or allergy makes daytime lens wear uncomfortable. The American Academy of Orthokeratology and Myopia Control (AAOMC) and the Orthokeratology Society or Oceania (OSO) recommend OK as "suitable for those unable to wear daytime contact lenses due to allergies or dry eyes." Whilst this makes intrinsic sense as OK should theoretically reduce the challenge to the ocular surface during waking hours to a no-lens situation, there is limited evidence on this issue.

Dryness or sensitivity symptoms to atropine are likely to be due to the preservative in the formulation rather than the atropine itself. Benzalkonium chloride (BAK), thimerosal and chlorobutanol are common preservatives¹² in multidose topical eye drops which can be associated with ocular hypersensitivity reactions.¹³ In the Low Dose Atropine and Myopia Treatment (LAMP) study, the occurrence of allergic conjunctivitis was reported as similar in all groups at 3-6%, indicating no difference in rates between the placebo, 0.01%, 0.025% or 0.05% formulations, which were preservative-free.¹⁴

The Report of the International Dry Eye Workshop (TFOS DEWS) lists ocular lubricants as a traditionally considered mainstay of dry eye therapy. Tear supplementation has minimal side effects, is easily accessible, and safe for use in children. However simple lubricants often don't treat the underlying reason for the dry eye sequelae. The DEWS also discusses that the appropriate diagnosis of the type of dry eye is crucial in effective treatment, so using symptom screening questionnaires, slit lamp examination and tear-specific diagnostic tests can help guide your diagnosis and management, as well as including the common predisposing factors in children, as described above.

• Consider dry eye as it can occur in children and symptoms may be under-reported compared to signs in young patients.
• Dry eye doesn't necessarily exclude contact lens wear as it may reduce symptoms in some patients, may be tolerable if replaced frequently, or orthokeratology could be considered.
• Remind young patients to adhere to reasonable screen time guidelines as increased screen time has been linked with dry eye disease. Read Screen time guidelines for children - resources for eye care practitioners for aged based guidelines and clinical communication advice.
• Get to the root cause of dry eye through additional testing, considering predisposing factors and learning more from the comprehensive International Dry Eye Workshop (DEWS) reports.