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The Royal Marsden Hospital Manual of Clinical Nursing Procedures - Lisa Dougherty [553]

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is the cornea which is selectively permeable and only allows the passage of water and not drugs. However, corneal resistance may alter if there is damage to the corneal epithelium (Kirkwood 2006). Many drugs will produce a similar effect on both the healthy and diseased eye. Drugs for use in the eye are usually classified according to their action.

Mydriatics and cycloplegics

These drugs cause pupil dilation and produce their effects by paralysing the ciliary muscle, stimulating the dilator muscle of the pupil (Figure 13.16) or by a combination of both. They are used mainly for diagnostic purposes and most have an anticholinergic action. The most commonly used preparations are cyclopentolate hydrochloride, tropicamide and atropine (BNF 2011).

Figure 13.16 Effects of mydriatics.

Miotics

These drugs produce their effects by contracting the ciliary muscle and constricting the pupil (Figure 13.17). Miotics help in the drainage of aqueous humour and are used primarily in the treatment of glaucoma. Examples are pilocarpine and carbachol (BNF 2011).

Figure 13.17 Effect of miotics.

Local anaesthetics

These render the eye and the inner surfaces of the lids insensitive. They are used before minor surgery, removal of foreign bodies and tonometry (measurement of intraocular pressure). The most widely used eye anaesthetics are oxybuprocaine and amethocaine (BNF 2011).

Anti-inflammatories

Anti-inflammatory drugs include steroids, antihistamines, lodoxamide and sodium cromoglycate. The most commonly used steroid preparations are dexametasone, prednisolone and betametasone (BNF 2011).

Corticosteroid eye drops should be used with caution as they can cause cataract formation or a gradual rise in intraocular pressure in a small percentage of people, particularly if they have a history of glaucoma (Forrester et al. 2002).

Antibacterials/antivirals/antifungals

Antibacterials and antivirals can be used for the active treatment of infections or as prophylactic treatment for eye surgery, after removal of a foreign body or following an eye injury. Antibiotic preparations in common use are chloramphenicol, neomycin and framycetin. Aciclovir is the only commonly used antiviral available as an eye preparation although ganciclovir is licensed for the treatment of acute herpetic keratitis (BNF 2011).

Artificial tears

Artificial tears are used when there is a deficiency in natural tear production. This can be due to a disease process, postradiotherapy treatment, as a side-effect of certain drugs or when the eye-blink reflex is absent. These artificial lubricants commonly contain hypromellose or hydroxyethylcellulose (BNF 2011). Additionally, pilocarpine can be given orally. The severity of the problem and the patient’s choice will determine the treatment.

Specific patient preparations

The eye to be treated must be ascertained and the unaffected eye should not be dosed. Ascertain if the patient is wearing contact lenses as contact of the medication with the lens can lead to increased drug absoprtion, visual distortion and discolouration of the lens (Chernecky et al. 2002). It may be necessary for the patient to remove the lenses and replace them with glasses for the duration of their treatment.

Procedure guideline 13.9 Medication: eye administration

Essential equipment

Non-sterile powder-free gloves

Low-linting swabs

Sterile 0.9% sodium chloride or warm water

Optional equipment

Eye swab

Medicinal products

Eye drops at room temperature

Preprocedure

Action Rationale

1 Explain and discuss the procedure with the patient. Ask the patient to explain how their eyes feel, if they are able to. To ensure that the patient understands the procedure and gives their valid consent (Griffith and Jordan 2003, E; NMC 2008b, C; NMC 2008c, C). To gain a baseline understanding of current problems or changes the patient is experiencing. E

2 Wash hands and apply gloves. To reduce the risk of cross-infection (DH 2007, C; Fraise and Bradley 2009, E).

Procedure

3 Ask the patient to sit back with neck slightly hyperextended or lie down. To ensure

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