The drops should be used to prevent dryness…this is more effective than just using them for symptomatic relief
The best advice to give a patient using tear supplements is that the drops should be used to prevent dryness, and that this is more effective than just using them for symptomatic relief. For example, if the eyes frequently feel dry at the end of the day, use tear supplements once or twice in the mid-morning.
Retention of the aqueous tears is a useful approach in some cases. Punctal plugs can be temporary or semi-permanent and are generally placed in the lower (sometimes also the upper) canaliculus to limit tear drainage. These can help retain tears in aqueous-deficient DED but are less helpful in cases of ocular surface inflammation as they cause stagnation of the tears and increased tear osmolarity.
As mentioned, ocular inflammation and meibomian gland dysfunction are intertwined, and the importance of treating lid inflammation has become widely recognised. Improved meibomian gland function can be gained from some of the treatments above, but inflammation responds best to topical corticosteroids. These can be very helpful in breaking the cycle of inflammation, but even the weakest steroids can have significant side effects.
Risks of topical ophthalmic corticosteroids include epithelial toxicity, crystalline keratopathy, orbital fat atrophy, ptosis, limitation of ocular movement, reduction in endogenous cortisol, raised intraocular pressure and cataracts. While cataracts can be corrected at any stage, glaucoma damage to the optic nerve is irreversible. Once the damage process to the optic nerve has started, it may continue to progress independently of the eye pressure.
Typically, the risks are highest with long-term corticosteroid use, which can be a problem with DED due to its chronic nature – patients are likely to seek out steroids and could use them unsupervised for long periods of time. It should be made very clear to the patient that steroids are for short-term use only.
Inappropriate use of topical corticosteroid in the presence of corneal infection is also a significant problem. The symptoms of an early herpetic keratitis, for example, can be similar to DED, but corneal infections can become blinding if steroids are used. Topical steroids should be prescribed with ophthalmic or optometric supervision.
Steroid-sparing medications are available (eg, topical cyclosporine) but are typically only prescribed by ophthalmologists and specialists in ocular surface problems.
A useful class of medications for treating meibomian gland inflammation are the oral tetracyclines, typically doxycycline or minocycline. They are also used to treat acne and rosacea, and are relatively safe. They have been shown to be effective at improving irritation symptoms and objectively proven to increase tear film stability. A typical dosage for meibomian gland dysfunction is 50mg or 100mg daily for six weeks.
Taking oral tetracyclines at bedtime or without fluids is a common cause of oesophagitis. Advise patients to take the tablets with food or a large glass of water, and to sit upright or stand for at least 30 minutes afterwards, to help prevent this adverse effect. Oral tetracyclines are contraindicated for children and pregnant women.
Oral azithromycin has been shown to be as effective as, and better tolerated than, the tetracyclines. The risks of QT prolongation should be considered in predisposed patients and in those taking antiarrhythmics, antipsychotic agents, antidepressants or fluoroquinolones. Azithromycin is usually given as a divided dose to reduce adverse gastrointestinal effects (500mg stat then 250mg/day for three days).