Eyecare includes eye disorders and their prevention, treatment and patient education. This is an important area of practice. Eye problems and traumatic disorders of the eye account for over 6% of all attendances at the Accident and Emergency Department in the UK, while worldwide, approximately 5 000 000 blinding injuries occur annually. Eye disorders are particularly common in older people and as the population ages, the number of people affected is increasing rapidly. Examples are cataracts, glaucoma and macular degeneration. Glaucoma and macular degeneration are both chronic conditions and it is very imprtant that patients should be able to apply their own medication if at all possible in order to maintain independence. Cataract removal is a common operation, now usually undertaken as a day-case procedure. The nurse plays an important role preparing patients undergoing cataract extraction preoperatively and teaching them how to use local medication during the postoperative period at home.

Local use of drugs on the eye – types of applications

The following preparations are used in the local treatment of eye diseases:

• eye lotions

• eye drops

• eye ointments

• subconjunctival injections

• injections into the anterior chamber at operation.

Whenever administering local preparations to the eye it is of paramount importance to ensure that the eye to receive treatment is clearly designated. Patients going to theatre for eye operations will usually have an arrow marked on the forehead pointing to the eye to be treated to avoid any confusion. Often only one eye is to be treated or the two eyes are to be treated differently. For example, after an operation for angle closure glaucoma in one eye, it may be necessary to dilate the pupil with mydriatic drugs. Instilling mydriatic eye drops into the incorrect eye could impair vision in the normal eye and be very disabling for the patient.

Eye lotions prescribed as collyrium

These are used to wash foreign material and irritants from the eye and some have a mild antiseptic action. They are applied using a giving set, eye bath or a soft plastic irrigation bottle. In an emergency the priority is to administer treatment quickly to the contaminated eye before damage is done to the conjunctiva and cornea.

The patient should lie back or sit in a chair with the head extended back. The lotion should preferably be warmed to body temperature and before washing the eye the lotion should be run into the medial canthus, the lids being firmly separated by the fingers. A towel held by the patient close to the face will absorb the run off. This is less unpleasant than pouring the lotion directly onto the cornea. The lotion should be irrigated slowly but steadily from the irrigation receptacle, the patient being instructed to move the eyes in all directions.

In emergency cases, as in chemical contamination, it is better to use plenty of running cold tap water at once rather than to lose time in starting the treatment. The irrigating fluid most commonly used in the clinical situation is normal saline. Alkaline chemical contamination can penetrate the eye by saponifying cell membranes, causing local production of soap and causing erosion to the cornea, tissue destruction and secondary vascular thrombosis; therefore, immediate treatment should be sought. At least 1 litre of normal saline solution should be used. Afterward use litmus paper to check the pH of the eye. If it is over pH 7, repeat with another irrigation of 1 litre of normal saline solution until the pH is 7 or below.

In cases of corneal damage, topical citrate and potassium ascorbate eye drops can improve the prognosis, though patients should be warned they do produce stinging. They can be used for acid or alkali burns to the cornea and are often supplemented with oral ascorbic acid (vitamin C) at high doses of 1.5 g a day to promote healing.

Eye drops prescribed as guttae

A number of drugs can be applied to the eyes by means of drops which should be instilled into the lower conjunctival sac. The patient is told to look upwards away from the dropper and the lower lid is held down with the finger. One drop only is instilled into the lower fornix and the patient is then told to close the eye for a short while and the excess is wiped away. When two or more eye-drop preparations are used at the same time of day, an interval of 3–5 minutes should be left between instilling two preparations, in order to avoid dilution and the overflow effect.

All drops and ointment should be sterile when supplied, and once opened can no longer be considered so.

Single dose unit packs are particularly useful for patients who require medication over long periods and who may develop sensitivity to benzalkonium chloride, the preservative present in most eye drops.

Nursing point

Drugs or preservatives in eye drops may become absorbed into or onto hydrophilic contact lenses and cause irritation. Therefore, lenses should be removed before eye drops are instilled and not worn again until the treatment is finished. Similarly, contact lenses should not be used with eye ointments. If a patient develops an eye infection, he or she should be advised to use disposable lenses until it has resolved or to use spectacles.

Eye ointments prescribed as oculentum

These are usually supplied in 4 or 5 g tubes with a long plastic nozzle. To apply, the lower lid is pulled down and the ointment is placed in the lower fornix of the eye. About half an inch or 1 cm of ointment is squeezed from the tube at each application. It is important to twist the tube upward so that the strip of ointment remains in the fornix as the tube is moved away from the eye.

Subconjunctival injections

This method of application is used to obtain immediately a high concentration of drugs such as anti-infective agents, corticosteroids or mydriatics in the anterior chamber. This would be appropriate in the treatment of an acute intraocular infection. This treatment is painful and the eye must first be thoroughly anaesthetized by the instillation of several drops of local anaesthetic. The injection is given with a hypodermic syringe and a fine needle. Some drugs are manufactured in a depot form and are bound to a base substance from which they are released slowly. For example, Depo-Medrone (methylprednisolone acetate) can be used as a steroid preparation for the local treatment of iridocyclitis (inflammation of the iris and ciliary body). It is given as a subconjunctival injection and its action is continuous over a period of 3–4 days.

Intracameral administration

For some diagnoses, it may be desirable to achieve high therapeutic concentrations of antibiotic drugs with a minimum of delay. This calls for delivery of the drug directly into the globe of the eye, either into the anterior chamber or the vitreous cavity.

Anterior chamber administration is frequently used during cataract operations, when, to constrict the pupil, the iris is irrigated directly with Miochol-E, which is an acetylcholine preparation. In severe intraocular infections – for example, postoperative endophthalmitis (inflammation within the eye, usually due to infection) – it may be necessary to remove a sample of the vitreous humour for bacteriological examination. It is timely to inject the vitreous cavity with broad-spectrum antibiotics. Antibiotics effective against a range of organisms can be used in this way, although care is needed to avoid any toxic effects on delicate intraocular structures such as the retina. Consequently, the injections need to be carefully prepared and used only in the recommended dosage, in volumes not exceeding 0.05–0.1 ml, and administration should generally be under sterile theatre conditions.

Types of drugs used

The following types of drug are in frequent use in the treatment of eye disorders:

• steroids and other anti-inflammatory drugs

• those which affect pupil size

• those used in the treatment of glaucoma

• local anaesthetics

• stains

• miscellaneous preparations.

Drugs can be administered to the eye by either local or systemic routes.

Antibacterial agents used in the eye

The three main classes of anti-infectives used in the eye are: antibacterials (also known as antibiotics), antivirals and antifungals. There are also anti-amoebics and antiprotozoals, which are commonly grouped with the antifungals. While many of the dose forms are available from proprietary manufacturers as mainline medicines, some must be ordered from special manufacturers who manufacture limited quantities in batches.

The antibiotics are summarized in Table 28.1.

**Table 28.1** Antibacterial agents used in the eye
Drug(s)	Spectrum
Amikacin	Gram-negative, mycobacteria
Bacitracin zinc+polymixin B sulphate	Broad, Gram-negative, coliforms
Benzylpenicillin	Streptococcus
Ceftazidime	Broad, Pseudomonas
Cefuroxime	Broad, Staphylococcus
Chloramphenicol	Broad
Ciprofloxacin	Broad, Gram-negative
Erythromycin	Broad, Streptococcus Chlamydia
Framycetin sulphate	Broad, Gram-negative
Fusidic acid	Staphylococcus
Gentamicin	Broad, Gram-negative, Pseudomonas
Levofloxacin	Broad, Gram-negative
Neomycin sulphate+gramicidin+polymixin B sulphate	Broad
Ofloxacin	Broad, Gram-negative
Trimethoprim+polymixin B sulphate	Broad, Gram-negative, coliforms
Vancomycin	Staphylococcus, Clostridium

Antibiotics are used to treat a wide range of eye infections and they may be administered in three ways:

• Drops are satisfactory for superficial inflammation such as conjunctivitis, but rapid dilution occurs because of the tears. The drops should be instilled at 2-hourly intervals at least, if a reasonable concentration of antibiotic is to be maintained.