Dry eye evaluation

Dry eye is becoming an increasingly common problem and this is in no small part due to our lifestyle. Factors as varied as medication, hormones and screen time can all contribute to symptoms.

At the milder end, using more regular lubricants can help. However, just as with back pain, treatment of symptoms isn’t the ideal for most people. For example with back pain, although painkillers help, they do not fix the hours spent seated at the desk that may have caused the problem.

A thorough evaluation, as with any evaluation involves taking a ‘good medical history.’ This should guide the tests and inform treatment decisions. The medical history will tell us about hormonal changes and medications such as HRT. It will also tell us about other medications such as proton pump inhibitors, certain blood pressure medications and antidepressants which may all have an effect on the ocular surface. There are a number of medical conditions which also can affect tear production. These include rheumatoid arthritis or Sjögren’s syndrome. It can take a number of specialists to work together to find the underlying cause and referral to a rheumatologist is sometimes required. In fact, early referral to a rheumatologist off the back of an eye symptom can lead to early and more successful treatment of a number of underlying conditions. As the saying goes, ‘“a stitch in time saves nine.”

The mechanism of dry eye is related to either an unstable tear film, which does not stay spread evenly over the ocular surface between blinks; or an insufficient amount of tears.

The stability of the tear film can be measured by the ‘tear film break up time’ (TBUT). If there is instability of the tear film, this can be due to inflammation of the ocular surface eg due to chronic conjunctivitis or due to eyelid pathology such as blepharitis. There are a number of treatment modalities for both and a detailed ocular examination is ideal.

Tear production can be tested by using a Schirmer test, which tells us about the quantity of aqueous tear production.

If there is insufficient tear production, the treatment is different to a tear film instability. It may be due to medication; age; hormones or systemic conditions such a Sjögren’s syndrome.

Commonly, there is insufficient tear production as well as an unstable tear film and a combined approach to treatment is necessary.

Treatment can include eye drops, however much more is needed if the dry eye is more persistent or severe. Ideally preservative free eye drops can be used such as Theloz Duo; Hylotears/Hyloforte; Hycosan or Cationorm. If there is a problem with the lipid component of the tear film, a drop containing some lipid can be used such as Optive Fusion or Thealipid.

Blepharitis treatment is outlined here, however when blepharitis is more severe or linked to an uncomfortable dry eye, treatment can be increased to include steroids or steroid sparing drops such as Ikervis. Systemic antibiotics can be used for their other anti-inflammatory properties eg Lymecycline. Additionally there is benefit demonstrated to medibomian gland expression and Intense Pulsed Light (IPL) treatment.

If there is insufficient tear production, punctual plugs can be used to block the lacrimal puncti. These are the openings to the tear ducts that are present on the upper and lower lids and drain tears through to the lacrimal sac. A plug is usually temporary as the ones that sit on the outside are prone to falling out and the ones that are placed inside the canaliculi usually last only 3 months. If successful, permanent cautery and occlusion of the tear ducts can be performed.

As well as reducing the tears draining away with plugs, there are medications that increase aqueous production by causing the secretion of more tears (as well as increasing secretion from many other glands as well!)

As with many treatments, there is a stepwise approach to the management of dry eyes. Patience and persistence do pay off as the underlying cause is a result of chronic pathology and the treatment takes a correspondingly long time to take effect.