Contact lenses and children 31 Chapter

31.4.4 Amblyopic occlusion

Soft lenses provide an alternative method of patching. They can be prescribed with a black occlusive pupil, an entirely opaque lens or simply a high plus power to fog the vision.

31.5 Therapeutic applications

31.5.1 Aphakia

Early treatment and optical correction are essential for bilateral aphakic infants, so contact lenses give significant long-term visual benefits. Extended wear soft lenses are rarely used and only as a prelude to daily wear because of the risk of infection. Rigid gas-permeable lenses can be fitted with confidence for children over 5 years but can also be attempted at an earlier age. Silicone rubber can be used with success where soft lens loss is a major problem (e.g. Silsoft, Bausch &Lomb; Zeiss Pace Optics) (Table 31.2).

Table 31.2  Typical specifications

PRACTICAL ADVICE

•Overcorrect babies for arm’s-length vision, which is the range of their visual world.

•Prescribe bifocal spectacles over the lenses for close work at school.

31.5.2 Albinism

Albinism is associated with nystagmus, ametropia (often with high astigmatism) and photophobia. A tinted rigid gas-permeable lens is best but often there is no visual improvement over spectacles.9 Tinted soft lenses are more comfortable and may well help infants if cosmetically acceptable; if significant astigmatism is to be corrected then toric rigid lenses should be used.

PRACTICAL ADVICE

•Carefully observe any nystagmus with rigid lenses because it may increase with the stress of adaptation.

•‘K’ readings are more easily obtained using an autokeratometer because of speed of measurement.

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31.5.3 Aniridia and iris coloboma

These conditions require an opaque iris lens to occlude the light even if there is no visual improvement. Colour matching of the good eye is important for psychological reasons.

31.5.4 Microphthalmos

Microphthalmic eyes may be fitted for cosmetic or visual reasons. They tend to have steep corneal radii (e.g. 6.80 mm) with high hypermetropia (e.g. +10.00 D), so that aphakic designs can be used. Unilateral amblyopic cases can be fitted with a tinted high positive soft lens where the plus power makes the eye look larger. This is easier to fit and more comfortable than a scleral shell.

31.5.5 Marfan’s syndrome

The ocular abnormalities, apart from a subluxated lens, include a large flat cornea and a prescription that will usually have high irregular astigmatism with lenticular myopia. The preferred choice for best vision is a rigid gas-permeable lens. Any residual astigmatism with either rigid or soft lenses can be corrected with spectacles.

PRACTICAL ADVICE

•A cosmetic lens for one disfigured eye is more often the parent’s idea rather than the child’s.

•Carefully consider the long-term effects, since a child often refuses to go out without the lens.

References

1.Barnard NAS. Hypnosis in contact lens practice. Contact Lens Journal 1989;17(5):159–60.

2.Speedwell L. Paediatric contact lenses. Optician 2002;224(5868):20–5.

3.Stone J. The possible influence of contact lenses on myopia. British Journal of Physiological Optics 1976;31:89–114.

4.Perrigan J, Perrigan D, Quintero S, Grosvenor T. Silicone-acrylate contact lenses for myopia control: 3 year results. Optometry and Vision Science 1990;67:764–9.

5.Walline JJ, Jones LA, Mutti DO, Zadnik K. A randomized trial of the effects   of rigid contact lenses on myopia progression. Archives of Ophthalmology 2004;12:1760–6.

6.Cho P, Cheung SW, Edwards M. The longitudinal orthokeratology research in children LORIC in Hong Kong: a pilot study on refractive changes and myopia control. Current Eye Research 2005;30:71–80.

7.Winn B, Ackerley RG, Brown CA, Murray FK, Prais J, St John MF. The superiority of contact lenses in correction of all anisometropia. Transactions of the British Contact Lens Association Conference 1986;95–100.

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8.Morris J. Contact lenses in infancy and childhood. Contact Lens Journal 1979;8:15–18.

9.Speedwell L. Contact lens fitting in infants and pre-school children. In: Phillips AJ, Speedwell L, editors. Contact Lenses. 5th ed. Oxford: Butterworth-Heinemann; 2007. p. 505–18.

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Therapeutic fitting with rigid gas-permeable and soft lenses

Contact lenses are used for therapeutic reasons to:

•Correct vision in eyes with existing pathology.

•Correct irregular corneal astigmatism by providing a new smooth optical surface.

•Promote healing by protecting denuded cornea and new epithelium from the pressure of the eyelids.

•Prevent epithelial breakdown.

•Relieve pain or foreign body sensation.

•Protect the cornea and, when used in conjunction with lubricating solutions, provide a moist environment.

©2010 Elsevier Ltd, Inc, BV

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