It is predicted that by 2020 many specialised nurses will be retiring (http://www.rcn.org.uk) at a time when a large percentage of the population will be over 60 years of age and by association there will be a higher incidence of VI/eye disease. The need for service modernisation which would improve efficiency and delivery of care (Cuber-Dochan et al 2006) and the reduction in junior doctors’ hours (Calpin-Davies 2001) have served as catalysts for developing the role of the health care professional in this dynamic field of health care. As the professional need and desire to develop ophthalmic knowledge (Marsden & Shaw 2007) continues, the nursing roles are evolving in response to the influence of technological, statutory and organisational change. These roles, which have increased both nursing autonomy and responsibility, include performing minor lid surgery, emergency eye care, glaucoma monitoring and cataract care among a variety of other nurse-led initiatives. The health care professional in all environments has a duty of care to be up-to-date in practice, to facilitate health promotion, screening, primary and secondary care (Nursing and Midwifery Council [NMC] 2008). The ocular conditions and diseases presented in this chapter will provide the reader with a sound knowledge base related to causes, diagnoses, management and related nursing care. Not all ocular conditions cause VI; many clinical conditions are successfully treated with medical and surgical interventions. The main causes of VI in the UK are cataract (p. 431) and glaucoma (p. 432), age-related macular degeneration (p. 443) and diabetic eye disease (p. 444).

The term ‘visually impaired’ will be used throughout this chapter as an alternative term for people who do not wish to be labelled as ‘blind’ or ‘partially sighted’, as they can feel that these terms are negative and misleading (http://www.afbp.org/). It is estimated, globally, that 135 million people are visually impaired (VI) with 80% having eye disease that is believed to be treatable or preventable (http://www.who.int). The risk of blindness in developing countries is 10–14 times higher than in developed countries and it is predicted that the incidence of VI will double by 2020, due to an increase in the population and longer life expectancy (Bunce & Wormald 2006).

The World Health Organization is at the forefront of Vision 2020 – The Right to Sight: A Global Initiative for the Elimination of Avoidable Blindness (http://www.vision2020uk.org.uk). The aim is to eliminate avoidable blindness as a public health problem by the year 2020 (http://www.who.int). The Royal College of Ophthalmologists (http://www.rcopht.ac.uk) estimates that 4.3 million people over 65 years of age in the UK have a VI in one or both eyes (http://www.guidedogs.org.uk).

Anatomy and physiology

It is important to understand that the structures that compose the eyeball do not themselves produce sight but serve as a gateway for visual impulses which are then processed via the optic nerves and tracts, the visual cortex and associated areas of the brain. Accessory structures play a vital role in enabling the eyes to scan and focus on objects in the environment and in protecting and maintaining the optical properties of the eyes.

The eye

The visual pathways and interpretative centres

The optic nerve runs from the posterior aspect of the globe and enters the cranial cavity via the optic foramen. The medial nerve fibres cross over to the opposite side at the optic chiasma (Figure 13.2) to join with the lateral fibres and form the optic tract before synapsing in the lateral geniculate body of the thalamus. The fibres then run in the optic radiations to the occipital cerebral cortex of the brain. The main blood supply to the eye is via the ophthalmic artery, a branch of the internal carotid artery.

Figure 13.2 The optic nerves and their pathways.

(Reproduced with kind permission from Waugh & Grant 2006.)

Accessory structures

The exposed anterior aspect of the eyeball is protected by the eyebrow, eyelids and eyelashes. The conjunctiva, a mucous membrane, lines the eyelids (palpebral conjunctiva) and reflects back on itself (bulbar conjunctiva) to cover the sclera. This fold forms the conjunctival sac or fornix and is an ideal site for the instillation of topical drugs. At the limbus, the conjunctiva is modified to form the epithelial layer of the cornea. The conjunctiva facilitates free movement of the eyelids over the globe.

The exposed surface of the eye is covered by a three-layered film of tear fluid. Mucous secretion from conjunctival goblet cells forms the first layer of the tear film and ensures an even spread of tears over the cornea. The middle layer is the watery fluid secreted by the lacrimal glands (situated under the upper orbital rim) and by the accessory glands in the conjunctiva. The outer lipid layer of tear film is secreted by the meibomian glands of the lids. This is thought to reduce the evaporation rate of tears and to prevent the lids sticking together during sleep. The main functions of tear fluid are to lubricate the eye, to facilitate O₂ and CO₂ exchange, to provide an optically smooth corneal surface and to cleanse the eye with a bacteriostatic enzyme called lysozyme. Excess tears are drained from the eye via the lacrimal punctum and apparatus at the inner canthus (nasal end of the lid margins) into the lacrimal sac and thence into the nose through the nasolacrimal duct (Figure 13.3). Posteriorly and laterally the globe is protected by the bony orbit, the extraocular recti and oblique muscles (responsible for tracking movements) and by orbital fat.

Figure 13.3 The lacrimal apparatus. Arrows show the direction of the flow of tears.

(Reproduced with kind permission of Waugh & Grant 2006.)

The physiology of vision

Light rays are bent (refracted) as they pass through the varying densities of the clear media of the cornea, aqueous, lens and vitreous to focus on the retina. The cornea is relatively constant in shape and is responsible for about two thirds of the refractive power of the eye. The zonules extend from the ciliary body into the lens through 360 degrees so that any contraction or relaxation of the body will change the shape of the lens and affect its focusing (refractive) power. The normal eye in its relaxed state brings rays of light from distant objects into sharp focus. However, for clear focusing on near objects, an autonomic reflex known as the synkinetic near reflex comes into play. This reflex involves accommodation, miosis and convergence, as follows:

• Accommodation – the ciliary body contracts and changes shape, thus releasing tension on the zonular fibres and allowing the lens to thicken and increase its refractive power. This allows objects at different distances to be visualised with equal clarity.

• Miosis, or constriction of the pupil, accompanies accommodation and ensures that light rays are concentrated to pass through the centre of the lens and focus on the macula.

• Convergence, or in-turning of the eyes, seeks out the object to be focused on.

Failure to focus may be described as ametropia, or refractive error (see Box 13.1).

Once the rays of light are focused on the retina, their energy is converted into neuroelectrical energy by the photoreceptor cells. These nerve impulses are transmitted via the visual pathway to the visual cortex. Here, they are interpreted as sensations of light, form and colour and are processed into images of objects that are given meaning by other cerebral areas (see Ch. 9).

See website for Multiple choice questions

Assessing the eye and visual function

Examination of structure

It is necessary to know what a normal eye looks like and the normal expectations for an eye recovering from surgery or disease. It is vital for nurses working with ophthalmic patients to examine the eye in a systematic way and to be able to recognise significant abnormalities. It is recommended the nurse works in good light using a well-charged pen torch and examines all ocular structures from outermost to innermost. The possible implications of clinical features that may be found in the course of an eye examination are listed in Table 13.1. For further information on initial visual assessment see Field & Tillotson (2008).

Table 13.1 Significance of clinical features found on eye examination

Structure	Clinical Features	Possible Significance
Lids	Bruising (ecchymosis)	Surgical handling
	Swelling	Trauma
	Drooping	Infection
	Increased lacrimation
	Discharge
Conjunctiva	Redness (injection)	Surgical handling
	Swelling (chemosis)	Trauma
		Allergy
		Infection
Cornea	Cloudy	Increased IOP
	Crinkled	Infection
	Fluorescein staining	Loss of AC
	Suture line not intact	Ulceration
	Penetrating injury
Anterior chamber (AC)	Hyphaema (blood in AC)	Hyphaema due to surgery should gradually resolve
		Increasing IOP = bleeding/inflammation
	Hypopyon (pus in AC)	Hypopyon = infection
	Shallow AC	Shallow = ? aqueous loss
Iris	Muddy	Inflammation
Pupil	Irregular shape	Iris prolapse
		Adhesions
		Trauma

Testing visual function

Visual acuity

Obtaining an accurate visual acuity (VA) assessment is vital in order to assist the clinician in the choice of treatment options. Visual acuity is the mathematical estimation of visual function for different distances.

Distance vision

This is tested using Snellen test-type charts, which display letters or pictures arranged in rows of precise and diminishing size (Figure 13.4A). Each eye should be tested separately, with the benefit, if worn, of any spectacles or contact lenses, to ensure that ‘best corrected vision’ is being checked. The eye not being tested must be completely occluded. In normal testing, patients are positioned 6 m away from the chart and asked to read each line aloud until they can no longer make out the letters. The result is recorded as a fraction of the distance from the chart in metres over the normal reading distance of the last complete line read, plus the number of extra letters read from the line below or minus the number of letters read incorrectly, e.g. 6/9 − 2 (Figure 13.4). If glasses or contact lenses are worn this is also recorded.

Figure 13.4 Eye testing charts. A. Snellen test-type chart; the standard method for testing visual acuity in the UK. B. ‘E’ chart for non-English speakers. The patient is given a wooden or plastic E, which they move to indicate the positions in which they see it on the chart.

Normal distance acuity is accepted as 6/6, although what the patient is likely to achieve will vary with their age. If the patient sees less than 6/12 or 6/9 (there may be variations from one eye unit to another), they may be asked to read the chart again, looking through a pinhole (PH). A pure refractive error should improve with this simple method of sharpening focus by cutting out peripheral light stimulation.

If the patient cannot read the top letter (6/60) then ability to count fingers (CF) at 1 metre, detect hand movements (HM) or perceive light (PL) is tested. Testing when the patient does not read or understand English can be facilitated by using a Snellen ‘E’ chart (Figure 13.4B). If the patient has learning difficulties, poor concentration or expressive dysphasia then VA testing can be done by using a Sheridan-Gardiner singles booklet in which single letters or pictures of varying size are presented one at a time and the patient is asked match them on a card with a limited choice of symbols. When increased sensitivity of testing is required the LogMAR system may be used at a distance of 4 m. It is conducted in a similar fashion to the Snellen test, but the scoring system for every letter missed is more rigorous (Marsden 2008).

Near vision

is tested in good illumination and the patient is asked to read text in various sizes of standard print that are prefixed with the letter N. N5 is accepted as normal reading acuity.

Binocular vision

involves simultaneous perception of an image by both eyes and fusion of the two images in the visual cortex to form a single image. Binocular vision is thought to play a role in depth perception. Having two eyes also widens the field of vision and counters gaps in the visual field caused by natural blind spots (Box 13.2).

Box 13.2 Reflection

Binocular vision

Look carefully straight ahead and note what you see. Now close one eye. What do you not see? Now repeat with the other eye. What do you no longer see?

The visual field refers to what the eye can see with respect to angle of view (rather than distance). Normally this is about 60 degrees nasally, 90 degrees temporally, 50 degrees superiorly and 70 degrees inferiorly. Assessment of the integrity of the visual field is essential in the management of glaucoma and an important aid to diagnosis of neurological disease and retinal detachment. In the primary care environment and in the absence of automated equipment visual field testing can be carried out by means of a simple confrontation test, whereby the examiner sits directly in front and approximately one metre from the patient and compares the patient’s field of vision with their own (Douglas et al 2005). In the ophthalmic setting it is performed by means of perimetry using field analyser systems to gain accurate measurements of visual field defects known as scotomas (Khaw et al 2004).

Colour-blindness

Colour vision depends on the normal functioning of the retinal cones. A colour-blind person is unable to distinguish between some colours – usually red and green. While approximately 8% of the male population is born with defective colour vision, this problem is estimated at only 1% in females. Colour-blindness can be congenital or acquired through certain conditions such as optic neuritis or drug dependency. For further information on colour vision deficiency see http://www.healthinfoplus.scot.nhs.uk.

The most common method of testing for colour blindness is by means of a series of Ishihara colour-dotted plates. A person with defective colour vision would be unable to distinguish the numbers from the surrounding background. Some occupations, such as pilots and electricians, require normal colour vision, usually for reasons of safety but there are no restrictions on driving cars, lorries or buses, as traffic lights have a fixed sequence and can be recognised by position rather than colour.

Eye changes with ageing

By age 70, most people will need some form of visual aid because the elasticity of the lens decreases with age. Focusing is affected as the cornea flattens, causing astigmatism (see Box 13.1). Retinal cells become less efficient due to deposits laid down by ageing pigment epithelial cells. Tear film is reduced in volume and altered in structure, with the result that tears evaporate more quickly, leading to dryness and irritation of the eye. Conversely, some elderly patients complain of watering eyes due to muscle laxity and malposition of eyelids (see Entropion and Ectropion, p. 444).

Nursing management and health promotion: preservation of vision

Health care professionals can do a great deal through health education and active intervention to help people preserve their vision by observing individual behaviour and general appearance; missed appointments, unkempt clothes and a reluctance to go out may suggest ocular problems (http://www.rnib.org.uk) (Box 13.3). Should any changes be noted, prompt action and referral to an optician to ensure early screening and accurate diagnosis are vital.

Box 13.3 Reflection

Visual impairment recognition

Consider the changes in behaviour or appearance that may be indicative of deteriorating vision. Check your ideas with information on the RNIB website – http://www.rnib.org.uk

The following will contribute to health education and promotion.

• Promote the maintenance of good health through a balanced diet, regular exercise and avoidance of smoking (Khan et al 2006). It is believed, although not proven, that this will reduce the risk of ocular degeneration.

• Encourage regular eye examinations, especially in people over 40 years of age and individuals in high-risk groups (e.g. those with diabetes or hypertension). In the UK free sight testing is available for those over 60 years as well as for those in high-risk groups, lower income groups and people over 40 years old who have a family history of glaucoma.

• Provide advice and ensure the correct use, storage and cleaning of glasses and contact lenses. It is vital that contact lenses are properly maintained and used according to optometrists’ and manufacturers’ guidance. If guidance is not followed, there is a risk of long-term, possibly permanent damage to the cornea, due to infection, ulceration or abrasion (Jackson 2008).

• Encourage the prompt treatment of eye infections and ailments to prevent long-term ocular damage.

• Both work and leisure-related eye injuries can be prevented by wearing eye protection; 85% of ocular injuries occur in males aged 20–40 with approximately 70% being the result of industrial accidents (http://www.rnib.org.uk). While statutory health and safety regulations and better supervision by occupational health nurses have helped to reduce the number of industrial eye injuries, lack of eye protection remains a problem (http://www.dh.org.uk). The wearing of eye protection is mandatory in certain work environments, e.g. chemical laboratories and any area where grinding of metal occurs (Health and Safety at Work Act [1974] and Personal Protective Equipment Work Regulations [1992]). The health care professional must be aware that education is vital as the lack of use of eye protection may be associated with poor reliability as well as an uncomfortable design which deters, rather than promotes wear (Box 13.4).

• Advocate the correct and safe labelling of chemical products, and ensure first aid (e.g. eye irrigation) is available for emergency use. Individuals in the workplace and at home should be urged to heed the labels on chemical products indicating whether they are harmful to the eyes and make a careful note of first aid instructions in case of accidental splashing.

• Ensure that visual display units (VDUs) are used in accordance with the Health and Safety Executive (2003) recommendations for short, frequent rest periods to prevent eye fatigue. Employers must provide an annual sight test for all VDU users.

• Promote the wearing of sunglasses. It is not known exactly what type of ocular damage exposure to sunlight can cause, but it is believed to contribute to long-term ocular changes, i.e. cataract, macular degeneration (http://www.abfp.org).

Box 13.4 Reflection

Concordance and compliance

If we accept that concordance is not necessarily the same concept as compliance or adherence (consult the Phamaceutical Journal Online – http://www.pharmj.com/ – and type in ‘concordance’ in the search box), how do you as a nurse see your role with a patient who is prescribed topical anti-glaucoma treatment?

The visually impaired person (VIP)

Good vision is generally taken for granted and therefore it can be difficult to appreciate fully the value and importance of vision in everyday life. For example, when blindfolded it is difficult to accomplish the most simple task, such as making a sandwich, even when in a familiar environment.

Certification of vision impairment (CVI)

Most visually impaired people have some residual sight and there are few VIPs with a visual acuity of no perception of light (NPL). An ophthalmologist is required to certify the degree of impairment (Table 13.2) and certify that the patient is either Severely Sight Impaired (SSI, previously known as blind) or Sight Impaired (SI, previously known as partially sighted). In England a ‘certificate of vision impairment’ form (http://www.dh.gov.uk) is used and in Scotland it is a ‘blind person’ form. For information regarding registration in Wales and Northern Ireland see http:www.rnib.org.uk.

Table 13.2 Defining visual impairment (adapted from the Royal National Institute of Blind People)

Type of VI	Definition/ Standards for CVI
SSI	VA less than 3/60 with full visual field (VF) VA between 3/60 and 6/60 with reduced VF VA 6/60 or above with reduced VF
SI	VA 3/60 to 6/60 with full VF VA up to 6/24 with altered VF VA up to 6/18 with large VF defect

Registration is completely voluntary and entitles the individual to many local and national benefits; however, rehabilitation support can be obtained without registration. The social worker visiting individuals in their homes and helping to arrange the appropriate support will explain these issues. Some areas also have the benefit of a mobility or rehabilitation officer who is specially trained to help newly registered individuals to relearn certain daily living skills, and to move about safely in their own environment. This may involve the use of special canes or guide dogs. Rehabilitation officers also teach communication and information technology skills and advise on retraining for employment. Their overall aim is to enable the visually impaired person to function as independently as possible.

People with impaired vision may be referred to a low-vision clinic and assessed by an optometrist or specialist nurse to determine the need for low visual aids (LVAs) in the form of a monocular telescope, for reading bus numbers at a distance, or a magnifying glass for near vision tasks such as reading newspapers. Closed circuit television (CCTV) allows the VIP to comfortably view a magnified image of material such as photographs or objects such as pill boxes with added clarity and so can help individuals to make best use of their residual sight. These professionals may also provide information and advice on adaptation or retraining for employment. Employers can also be advised by various agencies, including the Royal National Institute of Blind People (http://www.rnib.org.uk) and Action for Blind People (http://www.afbp.org) about the sophisticated electronic equipment now available for VI employees. The introduction of the Disability Discrimination Act (DDA) in 1995 made it unlawful to treat disabled individuals in a discriminatory way, stating that employers and service providers, including the NHS and Primary Care Trusts (PCTs), must make reasonable adjustments to their services, ensuring for example equal access for disabled persons (http://www.direct.gov.uk).

Considering the needs of the visually impaired person

All client care should be planned using a structured approach to assessment and implemented with an ongoing recognition of the degree of assistance the VIP actually wants. The principles for care listed below echo the tenets of the Roper, Logan and Tierney (1990) model for nursing which is based on activities of living; it is a nursing model in which care is orientated to the patient and provided in a way that enables or supports the patient.

See website Critical thinking question 13.1

Some general principles of care for the visually impaired person are outlined below:

• Communication. Approximately 80% of sensory information is obtained visually (http://www.guidedogs.org.uk). Perception through focused use of other senses, especially hearing and touch, will be therefore heightened (http://www.rnib.org.uk). Ensure the person has access to radio, talking books/newspapers, information in large print or Braille or on audiotape and other more sophisticated means of communication as required.

• When approaching the individual, address them by name and identify yourself. Describe what you are doing so that they feel involved. Remember also to inform the VIP when you leave, as otherwise they may not be aware of this.

• Orientation to place. If the person is at home the environment is familiar and it is therefore important to keep things in their usual place. Assistance should be given to help VIPs move around the community and workplace until they are confident to do so independently. Appropriate visual aids such as magnifiers should be used. If the person is admitted to hospital, it is the duty of the health care professional to orientate them (http://www.nmc.org.uk). Older people can become confused in this situation and need constant reassurance and support.

• Mobility. Early mobilisation should be encouraged in the home and hospital with appropriate assistance given. The preferred method of guiding a person with visual impairment is illustrated in Figure 13.5.

• Maintaining a safe environment. It is essential to remove any hazardous objects in the person’s environment. Doors should be fully open or properly closed. Fires should have guards. Loose flooring must be secured.

• Eating and drinking. Bearing in mind the patient’s functioning visual field, food should be placed close to the patient and the content and position of food on the plate should be described using a clock-face analogy. Plate guards, non-slip mats and using crockery that contrasts with the food colour can be helpful for those with severe visual impairment. Many safety devices are available for use in the home to help with cooking (http://www.rnib.org.uk).

• Personal hygiene and grooming. After initial orientation and help, the VIP should be encouraged to be as independent as possible.

Figure 13.5 Guiding a VIP. Before you set off, offer your arm to the VIP. Ask which side they prefer. They should hold your arm just above the elbow. Check that the VIP is ready to go. Always walk one pace in front and at the same pace as the person. Describe the environment and warn the VIP of any obstacles or changes in the journey, i.e. stairs – up or down, doors, kerbs. In this way, the VIP can sense any turning of the guide’s body and can walk more confidently. The long cane or guide dog is in the VIP’s ‘free’ hand.

(Reproduced with permission from the Medical Photography Department, St John’s Hospital.)

With good rehabilitation training and family support, the visually impaired person should be able to get around in their environment safely and effectively. It will take confidence, time and patience to achieve this level of ability, and the VIP will require understanding and ongoing support.

Nursing management and health promotion: ophthalmic care

The following principles must be followed when carrying out ophthalmic nursing procedures, not only in the peri-operative period but also in the context of emergency care and the clinic setting. The reader is urged to consult specialist ophthalmic nursing texts listed in the references section.

General principles for ophthalmic care

In relation to those conditions that require surgical intervention the term ‘intraocular surgery’ describes procedures that are performed inside the globe of the eye involving structures in the anterior and/or posterior segments. This chapter will focus on cataract, retinal detachment, glaucoma and corneal transplant. These conditions share common certain general priorities for ophthalmic nursing management but specific priorities relating to each condition are outlined below.

Alleviating stress and giving information

Anxiety levels for ophthalmic patients attending or admitted to hospital may be exacerbated by fear of blindness and loss of independence. It is important to anticipate and dispel any misconceptions that the patient may have about eye surgery. The patient should be given the opportunity to discuss particular fears and should be provided with realistic information that does not raise false expectations about operative results. The patient’s concerns about managing practical activities following ophthalmic treatment or surgery should be addressed and the individual should be reassured with information regarding what guidance and support will be available from the acute and primary health care team and from local organisations with a role in supporting the VIP.

If a local anaesthetic is to be used, the person may be concerned about their level of awareness during the procedure and about whether they will be able to cooperate. Depending on the patient’s visual acuity, it is often helpful to discuss the operation using a model of the eye. Some patients will want only the minimum details and so the nurse should provide the appropriate amount and depth of information for each individual in order that the patient’s wishes are respected. See Chapter 26 for further discussion of the principles of peri-operative nursing, anxiety, informed consent and information giving.

Asepsis and infection control issues

Although asepsis and infection control measures must be observed by the nurse and the underlying principles taught to patients and relatives, the nurse must be realistic about what the patient and relatives will manage in the home. Education and planning regarding self-care on discharge should be tailored to individual need and capability.

Each eye should be treated separately. Drops and ointments should only be used in the eye for which they are prescribed. In hospital, topical medication should be dated upon opening and discarded after one week (after 4 weeks in the community). These precautions and simple handwashing measures (see Ch. 16) will reduce the risk of eye infection, which can pose a threat to vision.

Instilling eye drops and ointments

If the patient is able to carry out self-medication, instruction in the instillation of drops can provide a good opportunity to begin a teaching programme for postoperative self-care. Eye drops are inserted into the middle to outer third of the lower conjunctival sac. To facilitate this, the patient is asked to tilt the head back and look up while the lower lid is gently pulled down (Figure 13.6). Dropping the solution onto the sensitive cornea will cause discomfort and trigger a reflexive squeezing shut of the eye. After drop instillation the patient is asked to close their eyes gently for 30 s to maximise absorption.

Figure 13.6 Instilling eye drops into the lower central fornix.

Eye ointment is instilled into the lower conjunctival sac with the patient’s head tilted back as described above. Contact of the tube with the eye should be avoided. For information about topical and systemic drugs and other ophthalmic preparations see http://www.bnf.org/bnf/.

Managing eye dressings

Pressure on the eyeball must be avoided. This applies particularly when cleansing the upper eyelids. A sterile, moist, dental roll is used to wipe from inner to outer canthus along the eyelash line and is discarded after a single use. Cotton wool balls can be used only if they have been thoroughly soaked and squeezed out to ensure that no dry fibres are protruding. Patients should be cautioned against rubbing their eyes. The cornea is vulnerable to abrasion injuries, particularly after the instillation of local anaesthetic.

Eye pads are used to apply pressure to the eye and occasionally for comfort when photophobia or lacrimation (tear production) is excessive. The term ‘double padding’ means that two pads are applied to the treated eye; padding both eyes at the same time is generally avoided to prevent the disorientation and distress that this sudden visual deficit will incur. Eye pads are applied after eyes have been cleansed (if required), examined and treatment instilled. Ensure that the eye is closed underneath the pad at all times to prevent corneal damage.

The eye pad is held in position and tape is applied by first attaching one end to the forehead, then stretching diagonally across the eye pad towards the lateral aspect of the cheek, where it is secured. The downward movement facilitates lid closure and the diagonal position of the tape permits facial muscle movement. To aid removal a tab should be made by turning under the top of the tape. The skin on the forehead and cheek are supported during removal of the tape to reduce any dragging movement on the eyeball. The eye is examined when a pad is removed and the pad must be inspected for signs of infection or haemorrhage before discarding.

When the eye cannot be closed voluntarily, e.g. in the unconscious patient, care should be taken to avoid corneal abrasion from bedclothes or other articles when attending to the patient. The cornea can be kept moist by the instillation of lubricants and lid closure can sometimes be improved with the application of paraffin gauze, as in the case of a sedated and ventilated patient.

Postoperatively the eye is protected by a plastic shield at night for up to a week. Dark glasses may be worn during the day to reduce the discomfort of glare; patients should be taught to put the glasses on over their forehead to avoid accidentally pushing the earpieces into the eye.

Irrigation

This is a procedure that is generally confined to the emergency or occupation health setting. When irrigating the eye, the warmed solution of sodium chloride 0.9% should be directed across the skin of the lateral cheek so as to prepare the patient for the solution coming into contact with the eye. After this the irrigating motion should be directed away from the nasal side of the sclera. This will wash harmful foreign material away from the lacrimal duct to the side of the cheek, where it can be received in a kidney dish (Box 13.5).

Box 13.5 Information

Irrigation of an eye

Copiously irrigate the affected eye(s), preferably with 1 litre of sodium chloride 0.9% via an i.v. giving set or ideally a Morgan lens (http://www.morganlens.com). Ensure the patient is comfortable, reclining with their head and neck supported. Clothing should be protected by waterproof cape and towels. Ask the patient to hold the receiver dish and to turn their head slightly to the affected side. Instill topical anaesthetic drops, e.g. proxymetacaine 1 to 2 drops. Pull down the lower eyelid and irrigate with a steady flow of fluid, while asking the patient to move their eye around and to evert the upper lid to ensure thorough irrigation. Continue irrigation for at least 15 minutes, re-instilling local anaesthetic drops as required. Remove particles or foreign bodies with moistened cotton bud or forceps. Wait 5 minutes prior to checking pH levels of the tear film, which should be 7.5 or below. Continue irrigation until this neutral pH is indicated when reading the colour reaction of a strip of universal pH paper when it touches the tear film in the lower fornix of the eye (Marsden 2008).