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Eye Examination

Essentials

  • An eye examination includes examination of the visual acuity of both eyes, separately and together, the state of the refractive media and eye structures, any strabismus, and the function of the visual pathway.
  • Staining the surface of the eye with a fluorescein drop or strip and examination under blue light will help to detect corneal ulcers and corneal inflammatory changes.
  • Measuring the intraocular pressure will help to detect acute angle-closure glaucoma requiring urgent treatment.

Visual acuity

  • Examine
    • with the patient wearing his/her glasses for distance vision and without the glasses
    • both eyes separately and combined visual acuity
    • distance vision using an appropriate chart at the distance given on the chart
    • near vision using a near vision chart.
  • Visual acuity is expressed in numerical values.
    • 0.8(-2), for example, means visual acuity up to line 0.8, with 2 letters not seen.
  • If visual acuity is below normal, it should also be tested using a pinhole occluder. If the pinhole occluder improves the result clearly, the loss of vision is often due to a refractory error.
  • Examples of visual acuity:
    • 1.0: normal good vision
    • 0.8: limit for group 2 driving licence
    • 0.5: limit for group 1 driving licence
    • 0.3 or below: low vision
  • See also article on examination of vision Assessment of Vision.

Strabismus

  • Cover and uncover tests are the most important examinations of patients with strabismus. Both can be done easily by a general practitioner.

Cover test

  • Pay attention to eye movements when covering one eye.
  • Do this with the patient looking at a near object and into the distance.
  • Performance of the cover test
    • Ask the patient to look into the distance.
    • Cover first the patient's left eye, inspecting the right eye.
    • If the right eye performs a corrective movement towards the nose (i.e. inward) when covering the left eye, the patient has manifest outward strabismus (i.e. exotropia, divergent strabismus) of the right eye.
      • Strabismus of the left eye can similarly be seen when covering the right eye.
      • The patient has no manifest strabismus if covering one eye does not cause a corrective movement in the uncovered eye.
    • Repeat the test asking the patient to focus on a near object.

Uncover test

  • In this test, inspect the eye being uncovered. Do this with the patient looking at a near object and into the distance.
  • Performing the uncover test
    • Ask the patient to look into the distance.
    • Cover and then uncover the patient's right eye.
      • Inspect the right eye when it is being uncovered.
      • If the eye being uncovered performs a corrective movement towards the nose (i.e. inward), the patient has latent outward strabismus (i.e. exophoria) of the right eye.
      • N.B.: You can repeat the test paying attention to the direction in which the eye moves when being covered. In a patient with latent outward strabismus of the right eye, the right eye being covered will move toward the temple, i.e. outward.

Visual fields (finger perimetry, confrontation testing)

  • Ask the patient to cover his/her left eye.
  • Sit down in front of the patient.
  • Ask the patient to look directly at you.
  • Move your fingers obliquely within each quadrant (upper temporal, upper nasal, lower nasal and lower temporal) from the periphery towards the centre.
  • Repeat the test with the patient covering his/her right eye.
  • Record the results, e.g.:
    • no visual field defect
    • binocular temporal visual field defect (bitemporal hemianopsia)
    • binocular right visual field defect (right homonymous hemianopsia)
    • binocular left lower quadrant defect.

Eye movements and diplopia

  • Eye movements should always be checked, particularly if the patient has diplopia or neurological symptoms.
  • Before checking eye movements, see whether the patient has strabismus.
  • Examination of eye movements
    • Ask the patient to keep his/her head still, with both eyes open.
    • Check eye positions in an H fashion:
      • First hold an object, such as a pencil, directly in front of the patient's eyes, then move it all the way to the patient's right, up right and down right, return to the centre, and repeat the movements in the opposite direction.
      • If you notice any deviations, repeat the test with each eye covered in turn.
      • Ask the patient in each eye position whether he/she sees the target as one or as two.
      • Record any abnormality.
  • Diplopia: establish whether it appears when looking with both eyes at the same time (binocular diplopia) or only when looking with one eye (monocular diplopia).

Pupils (direct and indirect examinations)

  • The pupils constrict in bright light and when looking at a near object.
  • When examining pupillary reactions, ask the patient to look into the distance all the time.

Pupil size

  • Examine whether the pupils are the same size; a difference of 1 mm or more is abnormal.
  • Is the size difference greater in bright or in dim light?

Direct pupillary reflex

  • Shine a bright light into the patient's eye and see whether the pupil constricts (direct pupillary reflex).

Indirect (consensual) pupillary reflex

  • If you have just tested the direct pupillary reflex, wait a while to allow the eye to recover.
  • Then shine a bright light into the eye and see whether the pupil of the other eye constricts (indirect pupillary reflex).

Accommodation and convergence constriction

  • Ask the patient to look first into the distance and then at a near object.
  • Inspect the pupils: if they constrict when looking at the near object, there is normal accommodation constriction.

Ophthalmoscopy

  • Ophthalmoscopy is done with the pupil dilated. Fifteen minutes before the examination, instill the mydriatic tropicamide into both eyes.
  • Examine the structures in the ocular fundus.
    • Is the optic disc normal or is there oedema?
    • Is the centre of best detailed vision (macula retinae) normal, can any haemorrhage be seen?
    • Does the retina look normal; are there signs of retinal detachment?

Red reflex

  • Examine the red reflex with an ophthalmoscope or with a bright light.
  • Darken the room for the examination. If possible, 15 minutes before the examination, instill mydriatic drops (tropicamide) into both eyes.
  • Look at the patient's eyes through an ophthalmoscope from a distance of about 50 cm.
  • An even, reddish orange red reflex is normal.
  • An abnormal red reflex may indicate:
    • corneal opacity
    • a haemorrhage or inflammatory cell accumulation in the anterior chamber
    • a cataract lesion
    • a haemorrhage or inflammatory cell accumulation in the vitreous body
    • retinal detachment
    • a retinal haemorrhage
    • an intraocular tumour.

Intraocular pressure

  • Can be measured with a rebound (iCare®) or Schiötz tonometer.
  • This helps to detect acute angle-closure glaucoma requiring urgent treatment, and poorly controlled glaucoma.
  • Normal intraocular pressure alone is not enough to exclude glaucoma. People over 40 should see an ophthalmologist once and then at intervals of no more than 3 years to exclude glaucoma.

Fluorescein staining

  • Instill a fluorescein drop into the eye or touch a fluorescein strip to the conjunctiva.
  • Use blue light to examine the eye surface.
  • Corneal inflammatory changes and ulcers can be seen as enhanced colour under blue light.

Examination of eye structures

  • Eye structures should be examined by inspection with the naked eye and using a magnifying device (loupes or an ophthalmoscope).

Eyelids

  • Note any malposition of the eyelids.
    • Turning inward (entropion)
    • Turning outward (ectropion)
  • Is there any loose skin in the upper eyelid, drooping so as to restrict the visual field (dermatochalasis, ptosis)?
  • Is the eyelid margin lower than normal (ptosis)?
  • Are there inflammatory changes on the eyelids (erythema, heat, swelling)?

Conjunctiva

  • Is the conjunctiva bright and transparent, as is normal?
  • Redness
    • Bloodshot conjunctiva
    • Pericorneal redness (around the cornea)
    • Mixed redness
  • Accumulation of inflammatory exudate (chemosis) underneath the conjunctiva
  • Growth of the conjunctiva onto the cornea (pterygium)
  • Increased pigmentation of the conjunctiva (such as conjunctival melanosis)

Iris

  • Does the iris look normal, and is its colour normal?
  • Are there any abnormal papillae or bulges?

Equipment needed for eye examination by a GP

ExaminationEquipment
Visual acuityVisual acuity chart
Pinhole occluder
Eye structuresMagnifying loupe
Ophthalmoscope
Penlight and blue light
Strabismus and combined visual acuityCombined visual acuity charts
  • Lang® or TNO®
Visual pathwayBright light source (penlight, ophthalmoscope): pupillary reactions
Finger perimetry
Intraocular pressureRebound (iCare® ) or Schiötz tonometer
Diagnostic medicationAnaesthetic eye drops
  • Oftan Flurekain® , containing both anaesthetic and staining ingredients
  • Oxybuprocaine
Mydriatic eye drops
  • Tropicamide (short-acting basic drug)
Drops or strips for staining the eye surface
  • Fluorescein drops
  • Fluorescein strip