Comprehensive Notes – Examination of the Eye

Preparation & Patient Interaction

  • Always begin with a structured, reproducible routine that examiners instantly recognise as safe clinical practice.
  • Steps to start the examination
    • Wash / gel hands and don gloves if required.
    • Introduce yourself (name, role) and confirm the patient’s full name and date-of-birth.
    • If no history is available, elicit a VERY brief focussed history (onset of visual symptoms, pain, preceding trauma, contact‐lens use, past ocular surgery).
    • Explain your intended examination, emphasising that the tests are painless and why each is being done.
    • Obtain consent and ensure the patient is comfortable with privacy / chaperone arrangements.
    • Ask explicitly whether the patient has any current ocular pain or sudden change in vision – these may mandate immediate modification of your exam order.
    • Position: patient seated on a height-adjustable chair facing you. You will need to move around (e.g. to view the red reflex from an angle).
  • Ethical / practical point: verbal consent and continuous checking for discomfort are vital, especially when shining bright lights into the eyes.

General Inspection

  • Scan the wider clinical scene first – tubes, oxygen, cardiac monitors may hint at systemic illnesses with ocular manifestations (e.g. thyroid eye disease in a patient attached to an endocrine drip).
  • Face
    • Note gross asymmetry (ptosis, facial droop) → can localise cranial-nerve lesions (III, IV, VI, VII).
    • Collateral information (old photos / relatives) helps detect acute vs chronic change.
  • Entire patient
    • Posture, head tilt (compensatory for diplopia), use of low-vision aids.
  • “Look once, look twice, compare sides” – the paired nature of the eyes makes side-to-side comparison your most powerful diagnostic tool.

External Eye Examination

  • Globe
    • Proptosis (forward displacement) or enophthalmos (sunken globe).
  • Eyelids & lash margins
    • Ptosis, blepharitis (red, crusting), stye/hordeolum, ectropion, entropion, eyelid tumours.
  • Anterior segment (sclera, conjunctiva, cornea, iris)
    • Conjunctival / episcleral injection, discharge, corneal opacities, abnormal iris colour or heterochromia.
    • Note that discharge character (watery vs purulent) can differentiate viral vs bacterial conjunctivitis.
  • Pupils – full details below, but at this stage already scan for asymmetry or irregular edge.

Cranial Nerve II – Visual Function

Visual Acuity

  • Test ONE eye at a time; occlude, do not press the fellow eye.
  • Near vision
    • Ideally a Jaeger or Sloan near-reading chart held at 40 cm40\,\text{cm}.
    • In its absence, use any fine print (e.g. newspaper) and document accordingly.
    • Ensure the patient wears their usual reading glasses.
  • Distance vision
    • Snellen chart placed exactly 6 metres6\,\text{metres} away (or a mirror setup for smaller rooms).
    • Record as the lowest full line read (e.g. 6/6, 6/126/6,\ 6/12 etc.).
    • If unable to read the top line, move to 3 m→1 m3\,\text{m} \rightarrow 1\,\text{m}, then assess "count fingers", "hand-movement" and finally "perception of light (POL)".
    • Pinhole test: repeat acuity through a cardboard pinhole; improvement suggests a refractive error.
  • Gross acuity screening in busy wards: ask the patient to identify a distant clock face or read signage through the window.

Colour Vision

  • Standard test = Ishihara pseudo-isochromatic plates (numerical or pathway plates).
  • Alternative bedside trick: compare the red colour of the "red-top" on a phenylephrine bottle between eyes.
  • Digital solutions (MDCalc, smartphone apps) are acceptable when paper plates are unavailable.
  • Beyond detecting congenital red-green defects, acquired colour loss can signal optic-nerve or macular disease (e.g. optic neuritis, early toxic maculopathy).

Visual Fields

  • Screening = Confrontation test.
    • Patient covers one eye; you mirror by covering the opposite eye.
    • Both fixate on each other’s open eye.
    • Bring a small target (finger wiggle / hatpin) from the extreme periphery along the diagonals into the centre; ask when it is first seen.
    • Check all four quadrants in each eye.
  • Quantitative tests: Goldmann perimetry (kinetic) or Humphrey (static) automated.
  • Common defect patterns & neuro-anatomical correlations (even if not shown in transcript, often examined):
    • Monocular field loss → lesion anterior to chiasm (optic nerve).
    • Bitemporal hemianopia → chiasmal compression (e.g. pituitary adenoma).
    • Homonymous hemianopia → post-chiasmal tract/radiation/occipital lobe.
  • Always document which quadrant is affected and whether it respects the vertical meridian (neurological) or horizontal (retinal).

Ocular Motility (CN III, IV, VI)

  • Ask the patient to keep the HEAD still and follow your target (pen tip) held ~30 cm30\,\text{cm} away.
  • Trace a large ‘H’ (or ‘double-H’) pattern to reach the six cardinal positions.
  • Enquire continuously about
    • Pain (orbital fracture, thyroid orbitopathy).
    • Diplopia (true double vs blurred image – dissociate monocular problems).
    • Visual blurring.
  • Observe for
    • Under-action or over-action of specific muscles → note limitation direction and cranial-nerve mapping.
    • Nystagmus: pathological if present before reaching extreme gaze, if asymmetric, or vertical.
  • Verbally name each nerve to show examiners you know the anatomy: "Up-and-out = superior rectus (III), down-and-in = superior oblique (IV)…"

Pupillary Examination

The three “S”s

  • Size – measure in mm if possible; note miotic or mydriatic extremes.
  • Symmetry – ≈20%\approx20\% of the normal population have physiological anisocoria, but difference widens either in light (parasympathetic defect) or dark (sympathetic defect, e.g. Horner’s).
  • Shape – a notch or irregular contour suggests posterior‐synechiae from uveitis or surgical trauma.

Light Reflexes (dim room, patient fixates at distance)

  • Direct reflex: ipsilateral constriction when illuminated.
  • Consensual reflex: simultaneous constriction in the opposite eye, proving intact mid-brain integration.
  • Swinging-light test for Relative Afferent Pupillary Defect (RAPD)
    • Rapidly alternate the torch between eyes every 2 s2\,\text{s}.
    • An eye with optic-nerve disease paradoxically dilates when the light swings onto it (only consensual pathway intact).

Accommodation Reflex

  1. Ask patient to look at a distant target beyond you.
  2. Present your finger / pen midline at 30 cm30\,\text{cm}.
  3. In a normal response pupils constrict, eyes converge and lens thickens (the latter two not directly visible).

Anatomical Pathway (Figure 4 summary)

  • Optic nerve fibres project to both pre-tectal nuclei → each connects bilaterally to Edinger-Westphal nuclei → parasympathetic fibres run with CN III to the ciliary ganglion → short ciliary nerves innervate sphincter pupillae.
  • Clinical pearl: because of bilateral projections RAPD is never caused by isolated CN III lesions.

Fundoscopy (brief mention)

  • Although a separate skill set, a complete eye exam is incomplete without fundus assessment.
  • Always darken room, use the right eye to examine the patient’s right eye, approach at 15∘15^{\circ} temporal to visual axis to visualise red reflex, then optic disc, vessels, and macula.
  • Red reflex absence → think cataract, vitreous haemorrhage, retinoblastoma (in children).

Additional / Special Tests

  • Full cranial-nerve examination (II–XII) when eye findings hint at neurological disease.
  • Extended colour-vision testing detects subtle macular dystrophies or toxicities.
  • Cover–uncover & alternating cover test
    • Diagnoses latent (-phoria) or manifest (-tropia) strabismus.
  • Imaging modalities
    • Slit-lamp biomicroscopy – corneal ulcers, anterior-segment inflammation.
    • Ocular ultrasound – vitreous haemorrhage, retinal detachment when media are opaque.
    • OCT – macular thickness, optic-disc cupping.
    • Fundus autofluorescence – retinal pigment epithelium integrity.

Integration with Systemic & Neurological Assessment

  • Endocrine: Thyroid eye disease presents with lid retraction, restricted upgaze, exposure keratopathy.
  • Vascular: Hypertensive or diabetic retinopathy visible on fundoscopy often predates systemic diagnosis.
  • Neurology: RAPD + colour-vision loss + pain on eye movement → optic neuritis (consider MS).
  • Trauma: Orbital blow-out fracture → restricted upgaze, infra-orbital numbness.

Practical, Ethical & Exam Tips

  • Speak throughout: "I’m now checking the patient’s near acuity with their own reading glasses … recording as N5 on Jaeger chart" – demonstrates technique and documentation.
  • If the patient cannot comprehend instructions (e.g. language barrier, delirium) document "unable to assess" rather than guessing normal.
  • Always replace or disinfect pen-torches and occluders to prevent cross-infection (conjunctivitis outbreaks!).
  • In an OSCE, time-keeping is critical – a well-rehearsed, logical flow scores higher than an incomplete, random scattering of tests.