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Examination of the eye

Last updated: June 17, 2021

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The evaluation of the eyes is an essential component of the physical examination. There are two types of eye examinations, basic and comprehensive. This article focuses on the comprehensive eye examination, a series of at least twelve tests to screen and diagnose common eye disorders. It should be performed on patients with ophthalmologic symptoms and annually on all individuals ≥ 40 years of age. Tests typically include evaluation of visual acuity, visual fields, the external eye structure (orbit, eyebrows, eyelids and margins, palpebral aperture, lacrimal apparatus, conjunctiva, sclera, cornea), the anterior ocular chamber (iris, lens, pupils), extraocular movements, and the optic fundus. Adjunct tests and procedures may be indicated depending on the findings of the initial exam.

For more information on the basic eye examination, see “Head and neck examination.”

The comprehensive eye examination screens and diagnoses common eye disorders; it consists of at least twelve tests. [1]

  • Definition: an ophthalmological examination used to determine the clarity or sharpness of central vision at various distances
  • Indications
  • Types of visual acuity [2]
    • Minimum detectable acuity (determines if an object is present or not)
    • Minimum separable acuity (identification of separation between two objects)
    • Minimum recognizable acuity (identification of the smallest characteristic of an object)
    • Minimum discriminable acuity (identification of changes in size, position, or orientation of an object)
  • Visual acuity tests
    • Snellen chart
      • An ophthalmological chart that displays several rows of capital letters of different sizes
      • Used to evaluate visual acuity
    • E chart
      • An ophthalmological chart that displays several rows of the letter “E” in different sizes and rotations
      • Used to evaluate visual acuity
    • Landolt ring
      • An ophthalmological chart that displays several rows of a ring with a gap (resembles the letter “C”) in different sizes and rotations
      • Used to evaluate visual acuity [2]
  • Procedure
    • Position the examinee at a predetermined distance from the chart (usually 20 feet/6 meters).
    • Ask the examinee to cover one eye and consecutively read the designated chart, beginning with the smallest row that can be read.
      • Snellen chart: The examinee reads the rows of letters out loud.
      • E chart: The examinee points or states in the direction that the “legs” of the letter E are pointing (up, down, left, or right).
      • Landolt ring: The examinee points or states in the direction that the gap in the ring is pointing (up, down, left, or right).
    • Normal findings: emmetropia (20/20 vision)
    • Abnormal findings
      • Reduced nearsighted vision, reduced farsighted vision, blurry vision, inability to distinguish the charts (only recognizing shadows or fingers)
      • Additional diagnostic tests need to be performed (e.g., pinhole test).
  • Clinical significance

  • Definition: a color vision test in which a set of color-dotted plates is used to diagnose deuteranopia (green color blindness) and protanopia (red color blindness)
  • Indications [4]
  • Procedure
    • The test consists of colored plates with numbers or shapes formed from dots of varying color and size.
    • Adequate lighting is necessary to properly view the plates.
    • The examiner shows the examinee the plates at random, generally starting with the number 12.
    • The examinee is given three seconds to detect the number or shape.
    • Normal findings: The examinee distinguishes all the colors, numbers, and/or shapes on the plates.
    • Abnormal findings
      • Failure to differentiate between colors, numbers, and/or shapes
      • Additional diagnostic tests need to be performed (e.g., matching tests, retinal examination).
  • Clinical significance: color blindness or dyschromatopsia (see “Color perception disorders” in “Diseases of the retina”)
  • Definition: An ophthalmologic examination that tests movement and alignment of the eyes (the examiner uses their finger or a specific target)
  • Indications
  • Procedure
    • Instruct the examinee to follow your finger while keeping their head immobile.
    • While standing in front of the examinee, trace a letter "H" in the air: The eyes should move in six directions (upwards, downwards, right, left, and diagonally).
    • Next, move the same finger towards the examinee's nose to test for accommodation: The eyes should converge while following the object to within 5–8 cm.
    • Normal findings: The examinee is able to perform the six positions of gaze.
    • Abnormal findings
  • Clinical significance

  • Definition: a type of ophthalmological examination used to detect the presence or degree of eye deviation.
  • Procedure: The examinee's eye is covered for a few seconds, and refixation movements are observed after the eye is uncovered.
  • Indications: suspected eye misalignment
    • Phoria: misalignment of the eyes when the patient views an object binocularly → disruption of binocular vision (heterophoria or latent deviation)
    • Tropia: misalignment of the eyes when looking with both eyes uncovered (heterotropia or manifest strabismus)
  • Types of cover tests
Overview of cover tests
Type Procedure Interpretation
Single cover test for heterotropia
  • Cover one eye for 1–2 seconds.
  • Observe for a shift in fixation in the uncovered eye.
  • Uncover the eye and observe both eyes for refixation movements.
  • No shift in fixation in either eye: no misalignment
  • Fixation shift in the initially uncovered eye: misaligned eye
  • Fixation shift in the covered eye on uncovering it: misaligned eye
Cover-uncover test for heterophoria
  • Cover one eye for 1-2 seconds.
  • Uncover the eye and observe it for a shift in fixation.
Alternating cover test
  • Cover one eye for several seconds , then cover the other eye, and begin alternating back and forth between the two.
  • Continually observe the eye that was initially covered.
  • Refixation movement of the occluded eye on being uncovered may suggest phoria.

  • Definition: an ophthalmological examination used to assess light sensitivity and identify patterns of vision loss
  • Indications
  • Types of visual field tests and their procedures [5]
    • Confrontation visual field exam: an ophthalmological examination used to evaluate for patterns of vision loss
      • Stand facing the examinee (20–30 cm away), ask the examinee to cover one of their eyes, and then cover your own eye on the same side (e.g., if the examinee's right eye is covered, the examiner covers their left eye).
      • Move your hand outwards beyond your own visual field (the area in which objects can be seen while focusing the eyes on a central point) until you can no longer see it, then move the hand inward while wiggling the fingers.
      • Ask the patient to mention when they can see the examiner's fingers.
      • This test should be performed for each visual field and then repeated on the other eye.
      • Normal finding: The examinee detects the wiggling fingers at the same time as the examiner.
      • Abnormal finding: Failure to detect the stimulus from a given direction indicates a visual field defect.
    • Automatic static perimetry: a systematic testing modality that uses a computer program; involves illuminating a static object to measure visual field function
      • Position the examinee in front of the machine.
      • One eye is tested at a time.
      • Ask the examinee to fixate their eyes on a target and press a button when a light appears.
      • This procedure is repeated several times using stimuli of different intensities but fixed sizes.
      • The computer program will create different patterns (maps) of visual sensitivity that correspond to different diseases of the eye.
    • Kinetic perimetry: An ophthalmological examination used to diagnose visual field defects; moving light targets are used to identify the edge of the examinee's visual field.
      • Position the individual in front of the machine.
      • Ask the examinee to fixate their eyes on a target and press a button when an object enters their visual field.
      • This process is repeated several times using a moving object of fixed size and intensity.
      • The computer program will create different patterns (maps) of visual sensitivity that correspond to different diseases of the eye.
    • Amsler grid: a chart with dots or a combination of vertical, horizontal, and/or diagonal lines used to measure visual field function
      • Position the examinee ∼ 30 cm away from the chart.
      • One eye is tested at a time.
      • Ask the examinee to fix their gaze on the central dot in the grid and describe the patterns they see.
      • Ask the examinee if they can see the sides and corners of the grid and if any squares on the grid are blurry or missing.
      • Record any abnormalities.
  • Clinical significance

Pupillary function test

Swinging flashlight test

For further information on pupillary abnormalities, see “Physiology and abnormalities of the pupil.”

  • Definition: a procedure in which the upper eyelid is turned inside out to examine the upper palpebral conjunctiva
  • Indications
  • Procedure
    • Ask the examinee to look downwards for the duration of the examination.
    • Pull the upper eyelid down with one hand.
    • Apply pressure to the upper eyelid (∼ 3 mm above the root of the eyelashes) with a cotton swab or glass spatula.
    • At the same time, pull the eyelid upwards and evert it over the cotton swab or glass spatula.
    • Keep the upper eyelid in the everted position and remove the cotton swab or glass spatula.
    • Inspect all parts of the conjunctiva, if possible; any foreign bodies should be removed.
    • Release the upper eyelid and instruct the patient to look upwards

  • Definition
    • An ophthalmological examination to evaluate for traumatic and nontraumatic disorders
    • Conducted with a binocular microscope, which allows for a three-dimensional view of the eye
  • Indications
  • Procedure
    • Room lights are dimmed or off.
    • Ensure that the correct configuration of the slit lamp microscope and that the examinee is correctly positioned in front of the examiner.
    • Apply topical ophthalmic anesthesia.
    • Ask the examinee to fix their gaze on a point in the distance.
    • Evaluate the lower and upper eyelids, conjunctiva, and sclera.
    • Evaluate the cornea (see also “Eye and orbit”).
      • Corneal color and transparency
        • Normal findings: clear, transparent
        • Abnormal findings: foggy color, presence of deposits
      • Sensitivity: Assess using a cotton swab while the examinee is looking at a fixed point.
        • Normal findings: blinking, lacrimation
        • Abnormal findings: decreased sensation
    • Evaluate the lens
      • Lens color and transparency
        • Normal findings: clear, transparent
        • Abnormal findings: foggy, white, opaque
      • Position
        • Normal findings: in the fossa
        • Abnormal findings: partially or completely present in another location (anterior chamber, vitreous chamber)
      • Shape
        • Normal findings: biconvex shape
        • Abnormal findings: cone-shaped, presence of a notch in the lens
    • Evaluate the iris
      • Color: compare both eyes
        • Normal findings: ayes are the same color
        • Abnormal findings: eyes are different colors, presence of pigmented spots
      • Pattern
        • Normal findings: radial pattern
        • Abnormal findings: muddy appearance, atrophy
  • Additional tests
    • Fluorescein stain
    • Seidel test
    • Tear break-up time
      • A test of tear film stability
      • During slit lamp examination, a fluorescein is applied to the tear film.
      • The time until the tear film breaks up or shows patchy coverage is measured.
      • Positive test: The tear film breaks up within 10 seconds.
      • Indicated when there is suspicion of dry eye syndrome
  • Clinical significance

  • Definition: an ophthalmologic examination in which a tonometer is used to determine intraocular pressure (IOP) [8]
  • Indications
    • Routine ophthalmological evaluation: determine baseline IOP
    • Suspected glaucoma
    • Ocular trauma
    • Before and after eye surgery
  • Procedure
    • Ensure correct configuration of the tonometer and correct positioning of the examinee.
    • Apply topical ophthalmic anesthesia.
    • Room lights are dimmed or turned off.
    • Ask the examinee to fix their gaze on a point in the distance.
    • Place the probe over the cornea.
    • Measure the IOP.
    • Normal findings: Standard values range between 10–21 mm Hg.
    • Abnormal findings: values < 10 mm Hg or > 21 mm Hg
  • Clinical significance
  • Definition: a component of the ophthalmologic examination in which an ophthalmoscope or fundoscope is used to visualize the retina, optic disc, choroid, and blood vessels
  • Indications
  • Procedure
    • Room lights are dimmed or off.
    • Mydriatic eye drops may be used to make visualization easier.
    • The ophthalmoscope's lens disc is switched to 0 diopters.
    • The ophthalmoscope is positioned ∼15 inches away from the examinee and slightly lateral to their line of vision.
    • Ask the examinee to fix their gaze at a point on the wall.
    • When examining the right eye, the examiner should hold the ophthalmoscope in their right hand and look through their right eye (and vice versa).
    • While keeping the ophthalmoscope fixed on the pupil, move the device towards the examinee's eye until almost touching the eyelids.
  • Components
    • Red reflex: an eye test that assesses the light reflection of the ocular fundus, which normally has a red color
    • Inspection of the external eye structures (eyelids, eyelashes, conjunctival abnormalities, pupillary abnormalities, and corneal abnormalities)
    • Inspection of the anterior eye segment
    • Assessment of the fundus
      • Optic disc (contour, color, cup)
      • Retina (Red reflex assessment), retinal vessels (clockwise assessment superior temporal, nasal, and inferior nasal and temporal)
      • Macula and fovea
      • Periphery of the fundus
Fundoscopic exam findings
Normal findings Abnormal findings
Optic disc
  • Located on the nasal side of the macula
  • Characteristics to assess (the three Cs)
    • Contour: should be clear and well defined
    • Color: should be yellow-pink
    • Cup: pale center within the optic disc that should occupy ⅓ of the optic disc size
Retina and retinal vessels
  • Arteries appear as light red and smaller than veins, which appear as dark red.
  • Most patients have spontaneous venous pulsations.
Macula and fovea
  • The macula is located temporally to the optic nerve and has a yellow color.
  • The fovea is located in the center of the macula and is dark-yellow color.
Periphery of the fundus
  • Pink or red color, smooth

Mydriatic drops are contraindicated in patients with narrow-angle glaucoma because they can induce an acute angle closure glaucoma.

Fluorescein angiography

Optical coherence tomography (OCT)

Electroretinogram

  • Definition: a diagnostic test that uses electrodes to measure the electrical activity generated by the retina in response to light stimuli
  • Indications
  • Types
  • Procedure
    • Ask the individual to sit in front of the electroretinogram machine.
    • Apply topical anesthesia.
    • Adjust the examinee's head on the support and ask the examinee to remain still.
    • Place the electrodes in contact with the cornea or contact corneal lens.
    • Present flashes to the individual (from lower to higher strength).
    • Normal findings: normal response to stimulus in light adaptations, dark adaptations, oscillatory potentials, and flickering stimuli
    • Abnormal findings: abnormal amplitude of response or time of response
  • Clinical significance

Electrooculography (EOG)

  • Definition: a test used to measure tear production [10]
  • Indications
  • Procedure
    • Ask the examinee to look upwards.
    • Pull the lower eyelid downwards.
    • Place a sterile strip of filter paper at the lower eyelid margin.
    • Repeat the procedure on the other eye.
    • Ask the individual to gently close their eyes and keep the paper in place for 5 minutes.
    • Remove the strips and measure the length of the wet area on each strip.
    • Normal findings: length ≥ 10 mm
    • Abnormal findings: length < 5 mm
  • Clinical significance

  1. Caltrider D, Gupta A, Tripathy K. Evaluation Of Visual Acuity. StatPearls. 2020 .
  2. Prum BE, Herndon LW, Moroi SE, et al. Primary Angle Closure Preferred Practice Pattern® Guidelines. Ophthalmology. 2016; 123 (1): p.P1-P40. doi: 10.1016/j.ophtha.2015.10.049 . | Open in Read by QxMD
  3. Angle-Closure Glaucoma. https://www.aao.org/munnerlyn-laser-surgery-center/angleclosure-glaucoma-19. Updated: December 18, 2013. Accessed: March 17, 2017.
  4. Primary Open-Angle Glaucoma preferred practice pattern. https://www.aao.org/preferred-practice-pattern/primary-open-angle-glaucoma-ppp-2015. Updated: November 1, 2015. Accessed: June 2, 2020.
  5. Visual field testing. https://www.aao.org/eye-health/tips-prevention/visual-field-testing. Updated: January 27, 2019. Accessed: January 20, 2021.
  6. Pasmanter N, Munakomi S. Physiology, Color Perception. StatPearls. 2020 .
  7. Yadav S, Tandon R. Comprehensive eye examination: what does it mean?. Community eye health. 2019; 32 (107): p.S1-S4.
  8. Fluorescein Angiography. https://www.aao.org/eye-health/treatments/what-is-fluorescein-angiography. Updated: January 1, 2020. Accessed: January 7, 2021.
  9. Stevens S. Schirmer's test.. Community eye health. 2011; 24 (76): p.45.
  10. Refraction 101. https://www.aao.org/young-ophthalmologists/yo-info/article/refraction-101-go-forth-and-refract. Updated: June 12, 2019. Accessed: January 20, 2021.
  11. Grehn F. Augenheilkunde. Springer Verlag (2005) ; 2006
  12. Lang GK, et al.. Augenheilkunde. Thieme Verlag (2008) ; 2008