Blinking: Dry Eyes and Dry Contact Lenses

The elimination of inefficient (incomplete) blinking habits is a crucial component in the optimum managment of many forms of dry eye and contact lens dryness problems. Adjunct Professor Charles McMonnies, in collaboration with the Institute of Eye Research, has produced a patient guide for the development of blink efficiency titled 'Blinking: Dry Eyes and Dry Contact Lenses'.

Take home copies of the Blink Instruction Guide can be obtained from the Institute for Eye Research on the following terms:

1. 100 copies $70 (per multiple of 100)
2. 50 copies $40
3. 25 copies $25
plus postage and handling

If you would like to purchase any of these options please send your cheque payable to Institute for Eye Research Ltd. at PO Box 6327 UNSW Sydney NSW 1466 Australia.

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CONFERENCE REPORT by Kurt Ostlund

BRITISH CONTACT LENS ASSOCIATION CONFERENCE: BIRMINGHAM (MAY 2006)
MEASURING AND OPTIMISING PATIENT COMFORT (INCOMPLETE BLINKING, DRY
EYES AND DRY CONTACT LENSES)

Presented by Adjunct Professor Charles McMonnies, School of Optometry and Vision Science, University of New South Wales, Australia

One of the lectures at the British Contact Lens Association conference in Birmingham was concerned with the role of blink inefficiency (incomplete blinks) in contributing to dry eye and dry contact lens conditions. Symptoms of dryness are one of the most common reasons for patients abandoning contact lenses and the role of incomplete blinking in contributing to these symptoms cannot be underestimated. Similarly, symptoms of dryness are very common in dry eye conditions including those that develop after refractive surgery and, again, incomplete blinking habits can be a significant causal factor.

Under normal conditions, complete blinks help maintain the mucin layer on the hydrophobic epithelium as well as help promote lipid secretion and distribution for optimum stability of the aqueous layer of the tears. Incomplete blinks disadvantage the exposed area of the eye or contact lens surface by reducing the efficiency of these mechanisms. For example, keratopathy that is limited to the inferior cornea in exposure dry eye conditions, and surface deposits that develop on the inferior portion of non-rotating contact lenses both strongly indicate an important role of incomplete blinking in these conditions.

Incomplete blinking usually occur as 10% to 20% of the normal blink rate but their critical significance is that each one approximately doubles the interblink interval and the opportunity for the inferior cornea to desiccate, or for deposits to precipitate on the inferior contact lens surface. When blink rates are lowered (as occurs during computer use) the interblink interval (drying period) due to an incomplete blink may be as long as 30 seconds for the inferior cornea or contact lens surface.

Contact lens patients who can benefit from improved blink efficiency include those with a history of dryness symptoms that increase toward the end of the day and toward the end of the lens wearing cycle. Patients with dry eye and exposure keratopathy, such as that which may occur following refractive surgery and other neurotrophic mechanisms, may also benefit from improved blink efficiency.

Professor McMonnies described his use of soft lens comfort scales to identify patients with end of day/end of lens cycle discomfort symptoms. He also advocated the refitting of new technology lenses that include improved wettability characteristics. Dr Inma Perez-Gomez also spoke at the BCLA conference and described how such lenses can depend on a blink-activated moisturiser release mechanism. The optimum performance of moisture releasing lenses may depend on overcoming incomplete blinking habits to reduce the risk of reduced wettability over the inferior lens surface.

Professor McMonnies described the Blink Instruction Guide (BIG) that he uses to help patients improve their blink efficiency. The BIG is based on the principles of behaviour modification and includes photographs that are used to create awareness and explain the significance of blink inefficiency, as well as the advantages of overcoming incomplete blinking habits. Education is the key to developing the patient motivation required to do the recommended blink efficiency exercises often enough to achieve long lasting results. The exercises are specified in detail in the BIG, although it was emphasised that the success of the BIG depends on the practitioner taking a few minutes to go through the information with the patient, to ensure that the content has been understood and that the exercises are going to be performed correctly.