Ophthalmology: Ophthalmic history and examination

Taking the history and recording the findings

You will find that time taken to obtain a good history from the patient is the key to getting the right diagnosis. Whilst you are listening to the patient, you should also observe his or her face and eyes, as much can be gained by simple observation before even measuring the visual acuity and using your ophthalmoscope. Firstly, however, you must
introduce yourself and tell the patient what you will be doing.

Aims

  • Take a good ophthalmic history.
  • Take a thorough medical history.
  • Examine the eye in a systematic way.
  • Record the eye examination in a standard fashion.

Structure of ophthalmic history

Presenting complaint (PC)

You should help the patient by asking general questions:

  • ‘What is the problem with your eyes?’
  • ‘What do you notice wrong with your vision?’ or
  • ‘Why did your optometrist (or optician) suggest that you be seen in the eye department?’

Sometimes the patient hasn’t noticed anything wrong, for instance glaucoma, and is being referred because the optometrist has noticed abnormal discs (possibility of glaucoma) or found an abnormal pigmented lesion in the retina (possibility of melanoma).

Ask specific questions:

  • Ask if the problem is acute (e.g. sudden) loss of vision. Establish which eye is involved or whether the
    patient thinks it is both eyes. Ask about associated symptoms such as headache, jaw claudication and temporal tenderness. This may help point the direction to a neuro-ophthalmic cause such as temporal arteritis (also called giant cell arteritis).
  • If the patient says that the problem is chronic (e.g. slowly developing) bulgy eye (proptosis or exophthalmos), ask when he or she first noticed it and whether it has changed, such as by getting worse, stabilizing or even getting better.

History of the presenting complaint (HPC)

Some questions to ask include: ‘When did the symptom first start?’ ‘Constant or intermittent?’ ‘How many attacks or episodes?’ ‘Any associated features?’ ‘Getting worse, staying the same or improving?’

Family history (FH)

Ask about eye conditions such as squint, glasses and glaucoma, childhood cataract, ocular tumours or any ‘eye disease’.

Past ocular history (POH)

Ask about previous eye problems, eye surgery or ‘lazy eye’ (amblyopia).

Allergies

Enquire about drug allergies

Past medical history (PMH)

This is very important in ophthalmology as so many conditions have medical causes. Ask about diabetes, hypertension, irregular heart rate, asthma and chronic obstructive airway disease (COAD), as betablockers used in drop form for glaucoma should be avoided in these patients. Other medical conditions, including multiple sclerosis, sarcoid, collagen disorders and inflammatory bowel disease, may present with ophthalmic problems. Enquire about nasal disease such
as sinusitis and hay fever, trauma or surgery.

Medications

Some medications may be contraindicated in eye surgery, such as warfarin and aspirin. Some questions to ask include: ‘Are you taking any tablets, even homeopathic ones or vitamins?’ ‘Are you taking aspirin or warfarin?’ ‘Has your doctor given you any eye drops or creams?’ ‘Are you taking any other tablets such as hormone replacement therapy?’ ‘Do you take any tablets for blood pressure or diabetes?’

Social history

Smoking can be a causative factor in retinal and optic nerve vascular occlusive disease. It is a recognized risk factor for thyroid eye disease (Graves ophthalmopathy) and for Leber’s optic neuropathy (Chapter 53). Some questions to ask include: ‘Do you smoke?’ ‘How many per day?’ ‘When did you stop?’

The eye examination

Before examining the patient, wash your hands. You can wear disposable gloves if you wish if you think they have an infective conjunctivitis.

A systematic approach is essential. Record your findings pictorially and in a standard way. Always tell the story and have a section for history, then examination, then findings or impression and a written plan. Always write your name, grade and signature at the end.

First measure the visual function.

  • Visual acuity. Measure the distance and near vision for each eye separately with their distance and near glasses or contact lens if they wear them. Use the pinhole if the vision is not as good as 6/6 or 20/20 Snellen or 0 on the Logmar chart, which will correct. The pinhole will correct for mild and moderate refractive disorders. Record if the
    vision was ‘unaided’ (without glasses or contact lenses) or ‘with’ (with glasses or contact lenses). Enquire if they have had corneal refractive surgery. If they have had refractive surgery, they may have one eye ‘set’ for distance and the other for near vision, which is mono-vision or blended mono-vision.
  • Visual fields.
  • Colour vision.

Systematic examination

  • Order of examination using slit lamp examination or ophthalmoscope— from front to back of eye.
  • Only dilate the pupils once you have done a thorough examination undilated right eye, then left; eyelids; external eye—conjunctiva and fornices; cornea; anterior chamber; lens; vitreous body; retina (optic disc, macula and porterior pole; peripheral retina).

Measure the intraocular pressure and examine the papillary responses.

Only then can you dilate the pupils! Make sure the patient is not driving, as the dilating drops will blur their vision for distance and affect their accommodation. Dilating drops usually take 15–20 minutes to work and the effect may last several hours.

For examination of posterior pole (fundus).


Visual acuity in adults

Measurement of visual acuity (VA) is the fundamental measure in ophthalmology and should be done prior to instilling any eye drops. It is important both clinically and medico-legally.

Aims

  • Measure distance and near VA.
  • Know why and how to use the pinhole test (PH).

Definitions

  • Visual acuity: an objective measure of what the person can see.
  • Pinhole test: a simple optical test used to detect the presence of small to moderate refractive errors.

Distance and near vision

VA must be measured, one eye at a time, for both distance and near type, with the patient wearing his or her best spectacle or contact lens correction.

  • Test the distance VA first.
  • Always start with the right eye.
  • If the eyelid is droopy (ptosis), use a finger to lift it gently above the visual axis.
  • Insert topical anaesthesia if needed (e.g. if with a painful corneal abrasion and blepharospasm).

The methods of vision testing described here can be used in children 6 years and older, but if an adult or an older child has a severe learning disability, then a method of vision testing appropriate to that individual should be used.

Distance vision

  • Snellen acuity: this is the traditional chart. Snellen vision is measured at 6 m (Europe) or 20 feet (United States).
  • LogMar acuity: this is increasingly being used for children and patients with poor vision or contrast problems and is useful for research and statistical analysis. The test is done with the patient 4 m from the chart. A LogMar score of 0 is normal, equivalent to 6/6 or 20/20; a score of 1.0 is equivalent to 6/60.

Principles of Snellen acuity

The Snellen chart has letters, but there are also versions with the ‘illiterate E’ and numbers.

  • The 6/6 (20/20) line is ‘normal’ vision—patients can often read the lower lines, 6/5 or 6/4, which is better than normal.
  • The number above the line describes the distance the patient is from the Snellen chart; 6/6 (20/20) means the patient is at 6 m (20 feet).
  • The number below the line denotes which line is seen, for example 6/12 (20/40). At 6 m, the patient reads the fifth line down (the ‘12’ line).
  • On the 6/6 (20/20) line, each letter is constructed to subtend an angle of 1 minute of arc at a testing distance of 6m.
  • On the 6/18 or 20/60 line, each letter subtends an angle of 3 minutes of arc; the 6/60 (20/200) line, 10 minutes of arc.
  • Each line is constructed in a similar way, so that letters on the 6/18 line subtend an angle of 1 minute of arc if tested at 18 m from the chart, and those on the 6/60 line at 60 m from the chart.

How to test distance Snellen VA

  • Patient sits 6 m from the chart.
  • Distance glasses or contact lenses are worn.
  • Occlude one eye completely using the palm of the patient’s hand or an eye occluder.
  • Ask the patient to read down the chart as far as possible.
  • Repeat for the other eye.
  • Use the pinhole if the VA is less than 6/9. If a refractive error is revealed, this patient needs to be assessed for glasses.
  • If the VA is worse than 6/60, even when using the pinhole, move the patient 3 m closer to the chart—if the top line is now read, record the VA as 3/60.
  • If the patient cannot see 3/60, sit him or her 1 m from the chart. If the chart still cannot be seen, proceed to measure ‘counting fingers’ vision. Ask how many fingers are held up, and if the response is accurate, record as CF (counts fingers) and the distance measured.
  • If CF cannot be seen, move your hand in front of the patient’s eye; if movement is accurately seen, record a VA of HM (hand movements), specifying the distance at which movement was seen.
  • If hand movements are not perceived, shine a torch light into the eye from various angles and record whether or not the patient has PL (perception of light), from which direction it is perceived, and the distance at which the torch was held.
  • If the patient still has no PL, record the vision in that eye as NPL (no perception of light).

Near vision

How to test near vision

  • Ask the patient to wear reading glasses if owned.
  • Test each eye separately.
  • Patient holds the near test chart (Figure 5.5) at about 0.3 m to read the smallest print that he or she can comfortably see.
  • The smallest print is recorded as N4 or N5, and the print increases in increments to the largest, which is N48.
  • Some near-reading test types use Jaeger type, which is similar but is recorded as J and the number of the line read.

Examination of visual fields

Measurement of the visual fields is also a fundamental test in ophthalmology and should be done prior to instilling any eye drops and with the patient’s full refractive error corrected. It is important clinically in patients with glaucoma and in neuro-ophthalmology.

Aim

Examine a visual field by confrontation.

Visual field

The visual field is a map representing the patient’s retina, optic nerve and central visual system.

  • Test visual fields by confrontation for detecting gross abnormalities and neurological problems.
  • Automated static perimetry is very sensitive and therefore better for detecting more subtle defects such as those seen in early glaucoma.

In your final exam, you may be asked to examine the patient’s visual fields by confrontation. You should also be aware of other methods of plotting visual fields, in particular the Goldmann, Humphrey and Esterman automated field analysers. The Esterman binocular visual field is useful for driving licence purposes.

Normal field of vision

In individuals with normal, healthy visual pathways, a typical map of the visual field is represented pictorially. There is a blind spot temporally in each field—this represents the optic nerve.

Examination technique

Necessary equipment for confrontational field examination: a white hat pin is best, but a biro with a red cap will do. Red desaturation is an early sign of visual pathway compression.

  • Introduce yourself to the patient, and ask him if he would mind you performing an examination of his ‘side’ or peripheral vision.
  • Show the patient the target you will be using, and ask if he can see it at a distance of 0.5 m.
  • If the patient cannot see the target at that distance, ask if he can see where your fingers are, and if so use them as your target.
  • If your fingers are not visible, use a pen torch.
  • Sit 1 m in front of the patient with your eyes and the patient’s eyes at the same level.
  • Always examine the right eye first to avoid any confusion.
  • Ask the patient to cover his left eye (make sure it is completely occluded), and if this is not possible, cover the eye with an occluder.
  • Ask the patient to look at your left eye and not to look for the target. Explain that you are examining ‘side’ or peripheral vision, and instruct the patient to say ‘yes’ whenever he becomes aware of the target in his peripheral vision (or ‘out of the corner of his eye’), making sure that his eye gaze is maintained on your left eye at all times.
  • Before you start testing peripheral vision with a small target, ask the patient if he can see your face clearly, or if any bits appear to be missing. This will pick up any gross field defects (e.g. if there is a left homonymous hemianopia, the right side of your face will be missing or blurred).
  • Now present your target equidistant between yourself and the patient, starting outside the field of vision in the superotemporal quadrant of the visual field, and bring it slowly in towards the centre, keeping the target equidistant between yourself and the patient at all times.
  • Maintain fixation on the patient’s right eye and make a mental note of when you first see the target in your peripheral field; compare this with when the patient can first see the target. You should both become
    aware of the target at the same time if there is no field defect.
  • Now repeat in the inferotemporal, inferonasal and superonasal quadrants.
  • Check the blind spot (note: if the patient has an obvious homonymous hemianopia, altitudinal field defect, bitemporal hemianopia or grossly constricted fields, there is no need to assess the blind spot). Examine one eye at a time. Ensure stable eye fixation at all times. Slowly bring a small target (a hat pin is best here) from the centre, on
    a straight line towards the temporal periphery. Ask the patient to indicate when the top of the hat pin disappears and when it reappears. Compare with your own blind spot.
  • Now examine the left field.

Other visual functions

In order to test the visual function, you have to perform three commonly used tests: the Ishihara colour plates, the Amsler grid and pupil reactions. Visual function is dependent on a healthy retina with healthy cones at the macula for colour vision and fine clear detail, and on the optic nerve fibres to convey the visual information to the visual centres.

Aims

  • Assess optic nerve function by testing (i) colour vision and (ii) pupil reactions.
  • Assess macular function using the Amsler chart.

Colour vision

Colour vision is detected by cones at the macula and is transmitted centrally via the optic nerve. It is a sensitive indicator of optic nerve function, and it is vital to assess when there is anterior visual pathway disease. It is also an indicator of central retinal (cone) function.

Optic nerve

  • Colour vision is a test of anterior visual pathway function—mainly of the optic nerve.
  • In optic neuritis (which may be associated with multiple sclerosis), papilloedema, optic nerve compression from tumour or Graves’ ophthalmopathy or any optic neuropathy, visual acuity may be normal and only colour vision is affected.
  • Acquired colour vision defects will be noticed by the patient, and they may be asymmetric. Note that a lesion compressing the optic chiasm may cause bilateral colour vision defects, is usually associated with a visual field defect and may progress.

Macula

  • Macular disease due to involvement of the cones, either congenital or acquired, causes a disturbance of colour vision.
  • An X-linked anomaly of the retinal cones in males will lead to red–green ‘colour anomaly’ or confusion. This is the common form of ‘colour blindness’.

Clinical assessment

Ishihara

  • Assess colour vision using pseudo-isochromatic ‘Ishihara plates’—a booklet of plates held at the normal reading distance. Each plate has a series of various sized colour dots arranged in patterns of hues to represent numbers. Red and green cone function is predominantly tested by this test.
  • The numbers are large to aid people with poor vision.
  • The first plate is a ‘test plate’, which identifies subjects whose reading skills or acuity levels exclude them from taking the test.
  • Ask the patient to read each plate, testing each eye separately to exclude a uniocular problem.
  • There are up to 17 plates of numbers; record colour vision as ‘17/17’ if the patient reads all 17 plates, or ‘5/17’ if she could read only five, or ‘test plate only’ if she could read only the test plate.
  • If the patient cannot read, ask her to trace the coloured pattern on the illiterate plates with her finger.

Red desaturation

Colour vision can be estimated by the patient looking at a red object (e.g. a red pen) with each eye. If there is an optic nerve or tract lesion on one side, the colour looks pink, dull or washed out with that eye. This is ‘red desaturation’.

Amsler chart

This chart is a test of macular function and is useful for picking up subtle paracentral scotomas seen in macular disease (e.g. age-related macular degeneration).

  • Ask the patient to hold the grid at arm’s length and to fixate on the central black dot.
  • Test each eye separately.
  • The patient must note whether or not the black lines look distorted (metamorphopsia) or absent (scotoma).
  • Ask the patient to draw in the area of the distortion or missing area.

Pupil reactions

The pupil reactions to a direct torch light (light response) and to accommodation (near response) are important to exclude optic nerve and neurological disease.

  • Direct light response: tests gross retinal and optic nerve function.

○ Sit opposite patient at arm’s length.
○ Ask the patient to look past you into the distance (avoids accommodative reaction).
○ Shine a pen torch light into one eye and assess pupil constriction— the direct pupil light response. The consensual reflex is the simultaneous constriction of the other pupil.
○ Repeat in the other eye.

  • Swinging flashlight test: this is to detect a relative afferent pupil defect (RAPD), which would be a sign of optic nerve damage.

○ Swing the light quickly back to the first eye, with the patient still looking into the distance—the first pupil should constrict, and the second equally constrict.
○ Repeat swinging the torch quickly from eye to eye to double check.
○ If one pupil dilates instead of constricts, this is an afferent pupil defect indicating a serious retinal or optic nerve problem.
○ Always ensure you use the brightest light source available when looking for a RAPD because abnormalities can be subtle.

  • Accommodation (near response): this is to test for neurological diseases.

○ Ask the patient to look from the distance fixation to a small accommodative target brought towards her slowly, up to a distance of about 20 cm.
○ Both pupils should constrict equally.