Eyes

Published on 02/06/2015 by admin

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Eyes

INTRODUCTION

Essential ocular conditions likely to present to a general practitioner also overlap to some extent with those seen in the emergency department. We start with important definitions, a list of basic equipment, tips on a focused ocular history and a concise and appropriate examination of the eye, and then discuss conditions that are common and/or serious (sight- or even life-threatening). It is important to have confidence with diagnosis and management, including prompt referral when required. This is by no means an all-inclusive list. Syndromes and ocular complications of systemic diseases are not covered.

The aim is to provide a practical and accessible guide for the general practitioner. Ocular conditions are divided into four main overlapping sections according to patient presentation to a general practitioner: red eye, loss of vision in the white eye, painful eye, and double vision. For example, a red eye is commonly painful as well, but by following the main symptom it is possible to exclude several diagnoses. Diagnostic summary flow charts can be used for quick reference.

HISTORY

The history involves both a specific ocular history and a comprehensive general history. Often the patient is distressed: they greatly fear losing their sight, and having the eyes touched is often psychologically threatening and physically uncomfortable.

HISTORY OF PRESENTING ILLNESS

What is the main or most serious complaint?

• Is the eye painful—duration, severity, associated and relieving features.

• Is the vision abnormal—missing letters or field, misty, coloured rings around lights, distance or near.

• Is the vision double—vertical, horizontal or torsional.

• Is the eye red—discharge, pain, location of redness: conjunctiva, limbus, sclera, sectoral or diffuse.

• Is there discharge—white versus yellow, sticky versus pus.

If there are multiple complaints, prioritise and address each one separately. Try to determine the order of events. Note symptom duration and any associated features such as ocular discharge, headache or cranial nerve palsy.

How did the patient attempt to treat the problem? A popular home remedy is to wash the open eye with tap water or weak tea. This can introduce bacteria and complicate the findings.

Over-the-counter (OTC) preparations often contain an antihistamine and/or a vasoconstrictor, which may mask conjunctival injection without treating the underlying condition.

PAST OCULAR HISTORY

Determine the pre-morbid level of vision, past acute and chronic conditions, which may recur. Note previous ocular:

• hospitalisations—corneal abscess, trauma, endophthalmitis

• surgery—cataract, glaucoma, strabismus, retinal detachment

• diseases—cataract, glaucoma, age-related macular degeneration

• need for glasses and/or contact lenses

• childhood strabismus (‘squint’ or ‘turn’)/amblyopia (‘lazy eye’)

• use of drops—OTC and prescription.

FAMILY OCULAR HISTORY

Familial diseases include:

• age-related macular degeneration

• cataract (especially juvenile)

• ocular dystrophies and syndromes.

MEDICAL HISTORY

Systemic diseases with possible ocular manifestations include: diabetes, thyroid disease, autoimmune disease, coronary and/or carotid artery disease, infections.

Systemic diseases that affect adherence to topical treatment: arthritis, dementia, tremor, stroke.

Systemic diseases that may be exacerbated by topical beta blockers: congestive heart failure, asthma, heart block.

A systemic disease whose management may be affected by topical beta blockers is insulin-dependent diabetes (may mask incipient hypoglycaemia).

MEDICATIONS

Medications with ocular side effects include: steroids, amiodarone, chlorpromazine, anti-TB and anti-HIV medications, beta-blockers, anticholinergics, tricyclic antidepressants, anticonvulsants and selective serotonin reuptake inhibitors.

Systemic medications that may be potentiated by topical beta-blockers are: beta-blockers, calcium channel blockers.

Potential systemic side effects from eye drops include: reactive airways disease, cardiac block, congestive cardiac failure (beta-blockers), allergic reactions (any drop), dry mouth, drowsiness, hypotension (alpha-2 agonists).

Ask specifically about eye drops—patients often forget to mention them. Look for overlap between topical and systemic drug classes and concurrent inappropriate use of both new and old drops (e.g. simultaneous use of two preparations, each containing beta-blockers).

Ask about allergy and/or adverse reactions to drops, sulfonamides, antibiotics and anaesthetic agents.

FAMILY HISTORY

Ask about diabetes, heart disease and problems with anaesthetics.

OCULAR EXAMINATION FOR GENERAL PRACTITIONERS

Equipment required:

• visual acuity chart—distance and near

• plastic occluder (large)

• red-topped bottle or hatpin

• torch with bright light (ensure ongoing fresh/rechargeable batteries!)

• ophthalmoscope / cobalt blue light

• cotton buds to evert eyelids, remove subtarsal foreign body

• drops: fluorescein, short-acting anaesthetic (benoxinate, tetracaine, proxymetacaine).

STRUCTURED EXAMINATION

Visual acuity

Distance visual acuity (Snellen VA)—expressed as a fraction, x/y where x is fixed as the distance the patient sits from chart and y is the line read. For example, if a patient sits at 6 metres and can read the ‘18’ line, VA is 6/18.

Occlude one eye at a time carefully and completely, and measure each eye separately. The vision should be measured with and without distance glasses (best corrected visual acuity: BCVA). A pinhole can be used if glasses have been forgotten or are not current. By eliminating non-paraxial rays, pinholes act as a ‘universal’ lens, indicating potential BCVA.

Visual acuity near (NA)—ask the patient to read letters at 30 cm, with reading glasses if required.

Note: glasses or the pinhole will correct refractive errors. Glasses won’t improve vision decreased by ocular conditions requiring treatment, so have the patient wear glasses for testing.

Pupil examination

Direct reflex to light—constricts the illuminated pupil. This measures ipsilateral optic nerve function (light going in) and oculomotor nerve function (pupil constriction) in that eye.

Consensual reflex to light—constricts the contralateral pupil, testing ipsilateral optic nerve function and contralateral oculomotor nerve function.

Relative afferent defect (RAPD)—there is paradoxical initial pupil dilatation in the illuminated eye when the torch is swung across from the other eye. With the patient fixating steadily at an object across the room, shine the light steadily for a few seconds into one eye, then swing it across to the second eye, watching the movement of that (second) pupil. If the first movement is constriction, the pupil response is normal; if the first movement is dilatation (and then constriction), that demonstrates a defect. Such a defect means that there is a relative abnormality in that optic nerve (compared with its fellow). It suggests optic neuropathy, such as optic neuritis or glaucoma (early to moderate loss is usually asymmetric).

FIGURE 28.1 Snellen Visual Acuity Chart

Horner’s pupil—on the affected side there is miosis, dilatation lag in dark, and mild upper eyelid ptosis.

The red reflex is the reflection of light off the retina through the pupil. It can be seen as ‘red eye’ on photographs and is diminished or abnormal with media opacities, such as cataract or vitreous haemorrhage.

Extraocular movements

With the patient’s head steady, ask them to watch the red bottle top or hatpin carefully while you draw a large, wide ‘H’ in the air. Corneal light reflexes indicate symmetrical movement.

Confrontation visual fields

Face the patient at a distance of about two arms’ length. Using a red top or hatpin, bring the object into view from four oblique directions. Initially test with both eyes open for a gross defect (such as hemianopia), then each eye individually.

Ocular examination

Always compare one side with the other, and use adequate illumination and magnification.

• Face—rash, asymmetry, trauma.

• Eyelids—rash, position, trauma, evert if foreign body is suspected.

FIGURE 28.2 Anatomy of the globe

• Test cranial nerves.

• Look at globe systematically—position, presence/location of any injection.

• Look at all layers of globe individually.

• Conjunctiva—pull down lower eyelids, evert upper eyelids.

• Cornea—with magnification, white light, fluorescein and cobalt blue light for abrasions.

• Episclera/sclera—redness, haemorrhage, ulceration, pallor (presence, extent, location).

• Iris and pupil—irregularity, asymmetry, reflexes.

• Lens—look at red reflex through ophthalmoscope to evaluate media opacities.

• Fundus—ask patient to look straight ahead to examine optic nerve head, at the light to see macula, up/down/side to side for mid-peripheral retina.

• Gently ballotte both eyeballs through relaxed upper eyelids (with patient looking down) and compare intraocular pressures between the eyes.

• Do not compare digital eye pressures with your own if you suspect infection!

OCULAR CONDITIONS

PREVENTION

As with other aspects of health, preventing eye disease is preferable to treating it. Simple preventive measures include:

• measures to prevent the spread of infection

• avoid eye trauma e.g. wear appropriate eye protection

• maintain a healthy lifestyle and avoid smoking, to reduce the risk of conditions such as diabetic retinopathy, retinal vein occlusions and macular degeneration

• adequately manage systemic conditions associated with eye complications

• secondary preventive measures with regular eye checks, especially in the presence of a family history for conditions such as glaucoma or diabetes

• adequate sun protection with protective eyewear, especially for those who are regularly outdoors in sunny environments

• low-fat diet (elevated cholesterol is a risk factor for macular degeneration ¹ and diabetic complications)

• high dietary intake of lutein/zeaxanthin ³—carotenoids in plants with orange, red or yellow colour, fish and green leafy vegetables. Also high intakes of omega-3 polyunsaturated fatty acids may decrease the incidence of nuclear cataract and higher intake of protein may decrease the risk of posterior subcapsular cataract.²

RED EYE

Red eye is very common and covers a broad spectrum of anterior segment diagnoses.

Conjunctivitis

Conjunctival inflammation is the predominant feature. Patients present with a red eye and mucopurulent discharge. The eyelids commonly become ‘stuck together’ overnight and difficult to open on waking. Ocular discomfort varies from surface irritation (e.g. sandiness/grittiness) to pain.

Signs include generalised conjunctival erythema, swelling and discharge. The conjunctiva develops distinct papillae (lymphoid tissue with a central vascular core) or follicles (collection of chronic inflammatory cells), depending on the aetiology. Vision is usually unaffected.

The multiple aetiologies, often separable by history, symptoms and discharge, include those described below.

Common

Bacterial conjunctivitis

(Staphylococcus epidermidis/aureus, Streptococcus pneumoniae, Haemophilus influenzae)

The conjunctiva appears ‘beefy red’ with yellow/green and mucopurulent discharge.

Treatment—antibiotic drops (e.g. chloramphenicol) initially every 2 hours during waking hours if severe, then q.i.d. for 1 week. Heat and lubricants can relieve symptoms. Antibiotic ointment can be used at bedtime.

The second eye usually becomes involved within a few days. Complete resolution is common within 1–2 weeks.

Viral conjunctivitis (predominantly adenovirus)

Follows contact with an affected person in epidemics, less commonly after a viral illness. Patients present with very red eye(s), lid swelling, watering and photophobia, and discomfort may be severe.

On examination there is marked conjunctival erythema and a clear watery discharge, pseudomembranes and subconjunctival haemorrhages if severe, and tender pre-auricular and cervical lymphadenopathy.

Treatment is symptomatic—cold or warm compresses and lubricant tear drops. For most patients this is adequate.

The condition is typically unresponsive to antibiotics and often worse in the first 3–7 days before slow resolution, which takes 2–3 weeks. It is rarely complicated by corneal inflammation (keratitis), which may lead to a longer duration and visual compromise through corneal scarring. These patients need to be referred to an ophthalmologist, who may prescribe weak steroid drops.

FIGURE 28.3 Red eye flow chart

Allergic conjunctivitis

This is usually seasonal (often with hay fever) or there is a known history of allergy. Patients present with red eyes, swollen eyelids, itching and watering. Conjunctival erythema is mild and pink, rather than red. The discharge may be whitish mucus, or clear and watery.

Treatment—involves flushing out the allergen with frequent use of unpreserved lubricant drops.

If severe, the patient should be referred to an ophthalmologist for anti-inflammatory and mast cell stabiliser drops such as fluorometholone and olopatadine or ketotifen.

The prognosis is usually good: most patients do not require long-term medication.

Uncommon

Patients with the conditions described below should be referred to an ophthalmologist for diagnosis, swabs and treatment co-managed with a sexually transmitted disease specialist.

Chlamydia

(Chlamydia trachomatis)

Patients complain of longstanding ocular symptoms, unresponsive to different treatments. A history of sexually transmitted disease is not always apparent, and the patient may be asymptomatic.

On examination there is conjunctival erythema, eyelid swelling, mucopurulent discharge and pre-auricular lymphadenopathy.

Treatment—includes systemic antibiotics (e.g. doxycycline for 3–6 weeks).

Gonorrhoea

(Neisseria gonorrhoeae)

While men may have urethral discharge, it is often asymptomatic in women.

The ocular symptoms and signs are florid. Patients present with red eye and creamy discharge. On examination there is profuse, thick, white purulent discharge and pre-auricular lymphadenopathy.

Keratitis occurs in severe infection and is vision threatening. It requires urgent referral to an ophthalmologist and hospital admission for intravenous antibiotic (e.g. ceftriaxone).

Prevention

This must be reinforced by the general practitioner. Infective conjunctivitis is highly contagious: make patients aware of this!

FIGURE 28.4 Infective conjunctivitis

Patients should avoid touching their eyes and avoid sharing towels and pillow cases. They should wash their hands frequently, and every time after touching their face or eyes.

Patients should be given a medical certificate for a week, or while the eyes are red and discharging, occasionally longer in the case of viral conjunctivitis.

Sexually transmitted infection requires co-management and education with a specialist in this field.

Blepharitis

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