Section ONE Preliminaries

which patients may describe as stinging, is frequently cured by sliding the lens onto the temporal sclera with a circular motion and allowing it to recentre. Other, slightly more efficient, techniques are: (1) to slide the lens in the opposite direction to the discomfort; and (2) to displace the lens first temporally and then nasally to give complete excursion over the cornea.9

PRACTICAL ADVICE

•If placed on the cornea with an air bubble, lenses are unstable at the moment of insertion and can be expelled by an involuntary blink.

•Most lenses (except some ultrathins) self-centre onto the cornea.

•Where necessary, place ultrathin designs, including some of the daily disposables, directly onto the cornea as these lenses are more difficult to recentre from the sclera.

•In difficult cases, allow the lens to dry on the finger for 15–30 seconds to prevent it from turning inside out and to make it easier for the tear film to attract it onto the cornea.

•Partially fold lenses to cope with very small palpebral apertures.

•With high plus or aphakic lenses, because of the effect of gravity, it may be easier to insert the lenses over a flat mirror with the patient’s head in a horizontal position.

•With difficult, tight-lidded patients, it is sometimes much easier to insert the left lens first, since the angle of approach is better for a right-handed practitioner.

Removal

Removal is effected by pinching from the eye after moving the lens onto the temporal or inferior sclera, or by applying lid pressure in a way similar to that for rigid lenses.

PRACTICAL ADVICE

•Rigid lens ‘scissors methods’, using the lids, can be tried with soft lenses but do not always prove effective because of their softness and size, particularly if ultrathin.

•Because of osmotic imbalance, a lens may sometimes appear to stick to the cornea. The eye should be irrigated with 0.9% normal saline and, after a short while, the lens may be drawn gently onto the sclera and removed.

References

1.Blakeney S. Infection control in optometric practice. Optometry in Practice 2009;10:1–12.

2.Seal DV, Kirkness CM, Bennett HGB, Peterson M, Keratitis Study Group. Populationbased cohort study of microbial keratitis in Scotland: incidence and features. Contact Lens and Anterior Eye 1999;22(2):49–57.

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Consulting room procedures and equipment 4 Chapter

3.Morgan PB, Maldonado-Codina C. Corneal staining: do we really understand what we are seeing? Contact Lens and Anterior Eye 2009;32:48–54.

4.Foulks GN. Challenges and pitfalls in clinical trials of treatments for dry eye. The Ocular Surface 2003;1:20–30.

5.Ficker L. Acanthamoeba keratitis – the quest for a better prognosis. Eye 1988;2(Suppl):s37–s45.

6.Cullen A. Contact lens care, Part 12 – Industrial contact lens sterilisation, in practice disinfection and daily disposables. Optician 2002;223(5840):22–7.

7.The College of Optometrists and the Association of British Dispensing Opticians.

Guidance on the Re-use of Contact Lenses and Ophthalmic Devices, September, 2001.

8.Cullen A. Contact lens care, Part 13 – Alternative methods of contact lens disinfection. Optician 2002;223(5845):22–7.

9.McMonnies CW. The critical initial comfort of soft contact lenses. Clinical and Experimental Optometry 1997;80:53–8.

Further reading

College of Optometrists Guidelines – Cross-Infection Control in Optometric Practice.

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Section

Preliminaries ONE

5.1 Discussion with the patient

It is important to discuss the various aspects of contact lenses at the first examination and assess potential suitability in relation to patient expectations, spectacle refraction, ‘K’ readings and slit lamp examination. The discussion, which can be reinforced by introductory patient leaflets, should cover many other related aspects of lens wear and fitting:

•General health, including allergies, hay fever and systemic drugs.

•Ocular health, previous infections or surgery, and family history.

•Vision, nature of Rx, amblyopia.

•Previous contact lens history – success or failure.

•Reasons for contact lens wear.

•Types of lens currently available.

•Preconceived ideas and misconceptions.

•Outline of fitting procedures.

•What is required in terms of aftercare examinations and hygiene.

•The correct replacement interval for disposable lenses and the proper use of solutions.

•Fees for initial fitting, lens costs and future aftercare.

©2010 Elsevier Ltd, Inc, BV

DOI: 10.1016/B978-0-7506-7590-1.00011-X