Introduction to Ophthalmology • Examination of the eye • External examination
External Examination of the Eye: Lids, Cornea, Iris, Pupil and Lens
A systematic external eye examination is a high-yield bedside skill. It begins before touching the patient: observe facial symmetry, eyelid position, redness, discharge, globe position and the patient’s ability to fixate. Then examine the lids, conjunctiva, cornea, anterior chamber, iris, pupil and lens with appropriate illumination and magnification. Always compare right and left eyes, and measure visual acuity early.
Urgent warning: Do not manipulate a suspected open globe, remove an embedded foreign body, perform tonometry, force the eyelids open or apply a tight patch. A painful red eye with reduced vision, corneal opacity, abnormal pupil, proptosis, penetrating/chemical trauma or painful restricted movements requires urgent ophthalmology.
Learning objectives
- Prepare a patient and perform a safe, structured external examination.
- Assess facial symmetry, lids, lashes, lacrimal system, conjunctiva, sclera, cornea, anterior chamber, iris, pupil and lens.
- Recognise normal findings and clinically important abnormalities.
- Use fluorescein, lid eversion, magnification and slit-lamp principles safely.
- Document findings and identify emergency referral criteria.
1. Preparation and sequence
- Introduce yourself, confirm identity, explain the examination and obtain consent.
- Ask about pain, photophobia, trauma, contact lenses, surgery, chemical exposure and visual change before manipulating the eye.
- Clean hands; use gloves if discharge, blood or chemical contamination is possible.
- Provide good diffuse light, then a focused oblique light and magnification if available.
- Examine from general to specific, right to left, without pressing the globe.
- Test distance acuity, pupils and movements before drops when clinically safe.
- Use fluorescein or lid eversion only when indicated and trained; avoid topical anaesthetic outside supervised examination.
| Sequence | Look for |
|---|---|
| General appearance | Distress, photophobia, head posture, facial asymmetry, rash or trauma. |
| Globe position/orbit | Proptosis, enophthalmos, displacement, swelling, pulsation. |
| Lids/lashes | Ptosis, oedema, wounds, entropion, ectropion, trichiasis, vesicles, closure. |
| Conjunctiva/sclera | Injection pattern, chemosis, discharge, follicles/papillae, haemorrhage, jaundice. |
| Cornea | Clarity, shine, surface, foreign body, ulcer, scar, oedema and contour. |
| Anterior chamber/iris | Depth, cells/flare if slit lamp, hypopyon, hyphema, iris pattern and synechiae. |
| Pupil | Size, shape, equality, light/near response and RAPD. |
| Lens/red reflex | Transparency, cataract, dislocation and symmetry of red reflex. |
| Motility | Alignment, range, pain, diplopia and nystagmus. |
2. General appearance and orbit
- Observe whether the patient keeps the eye closed, shields it from light, rubs it or has severe distress.
- Compare globe position from the front and above: proptosis is forward displacement; enophthalmos is posterior displacement; dystopia is abnormal vertical/horizontal position.
- Look for periorbital bruising, swelling, laceration, emphysema, crepitus, rash or vesicles.
- Assess facial symmetry and head posture. A compensatory tilt or chin position may indicate strabismus or ocular-motor palsy.
- Palpate orbital margins gently only when fracture/open globe is not suspected and avoid pressure on the globe.
Orbital emergency clues
Rapid proptosis, tense eyelids, reduced VA, RAPD, high IOP if safely measured, severe pain, ophthalmoplegia, colour desaturation or loss of light perception suggest orbital compartment syndrome. Fever, proptosis, painful restricted movements and systemic illness suggest orbital cellulitis. Both require immediate escalation.
3. Eyelids and eyelashes
| Structure/finding | Normal appearance | Abnormalities and significance |
|---|---|---|
| Upper/lower lid | Skin intact, margins appose the globe and blink is complete. | Oedema, laceration, bruising, tumour, lagophthalmos or lid malposition. |
| Ptosis | Upper lid covers only a small superior corneal area. | CN III palsy, Horner syndrome, myasthenia, muscle disease, aponeurotic or mechanical cause. |
| Entropion | Lid margin turns outward/neutral; lashes away from cornea. | Inward turning causes trichiasis and corneal abrasion. |
| Ectropion | Punctum rests against globe. | Outward turning causes tearing, exposure and conjunctival inflammation. |
| Trichiasis | Lashes point away from ocular surface. | Lashes rub cornea, causing pain, photophobia and recurrent epithelial injury. |
| Lagophthalmos | Complete gentle closure. | Exposure keratopathy in facial palsy, proptosis, sedation or unconsciousness. |
| Lid margin | Clean, smooth, no focal tenderness. | Blepharitis, stye/hordeolum, chalazion, crusting, meibomian dysfunction. |
| Canthi | Medial/lateral angles intact. | Medial canthal trauma may injure canaliculi; document and refer. |
Inspect the lid margin with the patient looking down and ask the patient to blink. Do not squeeze an acute lesion or manipulate a laceration until globe and lacrimal structures are assessed.
4. Conjunctiva and sclera
Conjunctiva
Inspect the palpebral conjunctiva by gently pulling down the lower lid. Upper-lid eversion may be needed for a subtarsal foreign body, but avoid it when open globe or severe trauma is suspected and seek trained assistance.
| Finding | Description | Possible cause |
|---|---|---|
| Diffuse injection | Superficial vessels over bulbar conjunctiva. | Conjunctivitis, irritation, allergy or dry eye. |
| Ciliary flush | Deeper circumcorneal redness. | Keratitis, uveitis or acute glaucoma. |
| Chemosis | Conjunctival oedema/ballooning. | Allergy, infection, trauma or orbital congestion. |
| Follicles | Small pale elevations, often lower fornix. | Viral/chlamydial infection or topical-drug reaction. |
| Papillae | Raised vascular cobblestone surface, often upper tarsal. | Allergy, contact-lens reaction or chronic irritation. |
| Subconjunctival haemorrhage | Well-defined red patch. | Spontaneous, trauma, strain, hypertension or anticoagulation. |
| Foreign body | Visible particle or focal inflammation. | Requires safe removal/irrigation and corneal assessment. |
Sclera
- Normal sclera is white, although mild pigmentation or yellowing may be physiological or systemic.
- Diffuse yellowing suggests jaundice; focal pigmentation may be benign or pathological.
- Episcleritis is usually sectoral, superficial and milder; scleritis causes deep severe pain, tenderness and sometimes reduced vision.
- Do not press on a tender or traumatised globe. Deep violaceous redness with pain merits urgent ophthalmic evaluation.
5. Corneal examination
Inspect the cornea with oblique light, magnification or slit lamp. Assess the lustre, transparency, contour, surface, epithelial integrity, vessels, foreign bodies and depth of any lesion.
| Corneal feature | Normal | Abnormal finding |
|---|---|---|
| Clarity | Transparent; iris detail visible. | Haze, oedema, infiltrate, ulcer or scar. |
| Surface/lustre | Smooth, wet, reflective tear film. | Punctate staining, abrasion, recurrent erosion or exposure changes. |
| Contour | Regular dome-shaped surface. | Keratoconus, bulging, laceration or irregular foreign body. |
| Vessels | No central vessels. | Neovascularisation from chronic hypoxia/inflammation. |
| Arcus | Peripheral grey-white lipid ring, often age-related. | Early/prominent arcus may prompt systemic risk assessment; it should not explain acute pain. |
| Infiltrate/ulcer | Absent. | White focal lesion, epithelial defect or stromal haze; urgent keratitis assessment. |
Fluorescein staining
- Fluorescein highlights epithelial defects under blue light. Instil a sterile strip/drop according to local protocol and avoid contamination.
- Diffuse punctate staining may reflect dry eye, exposure, toxicity or viral disease.
- A linear defect may indicate a foreign body under the lid; a branching dendritic pattern suggests herpes simplex and requires specialist assessment.
- A corneal ulcer, infiltrate, hypopyon or a positive Seidel leak is urgent. A Seidel leak means aqueous is escaping through a wound; do not press on the eye.
6. Anterior chamber
- Estimate depth with oblique illumination; a very shallow chamber increases concern for angle closure.
- With slit lamp, cells are suspended inflammatory leukocytes and flare is protein haze from blood–aqueous barrier breakdown.
- Hyphema is blood layering in the chamber, commonly after trauma; protect the eye and seek urgent review.
- Hypopyon is a visible inferior layer of inflammatory material, suggesting severe infection or inflammation.
- Do not mistake a normal iris shadow for pathology; use a trained examiner and proper illumination.
7. Iris and pupil
| Assessment | Technique | Abnormalities |
|---|---|---|
| Colour/pattern | Compare both irides in good light. | Heterochromia, inflammation, atrophy or trauma. |
| Shape | Look for round, regular pupil and iris contour. | Irregular “teardrop” pupil suggests penetrating injury; posterior synechiae may distort it. |
| Size/equality | Measure in bright and dim light. | Anisocoria; interpret according to which lighting condition increases it. |
| Light response | Direct and consensual responses. | RAPD, sluggish/fixed pupil or abnormal efferent response. |
| Near response | Fixation on a near target if appropriate. | Accommodation/convergence abnormality or neurological dissociation. |
Acute anisocoria with ptosis, diplopia, severe headache, eye pain or neurological deficit is an emergency. An irregular pupil after trauma may indicate an open globe.
8. Lens and red reflex
- Inspect the lens through the pupil with oblique light and a direct ophthalmoscope. A clear lens allows a bright, symmetric red reflex.
- Cataract: lens opacity causing gradual blur, glare and reduced red reflex.
- Lens dislocation/subluxation: may follow trauma or connective-tissue disease; look for phacodonesis, an irregular depth or displaced lens.
- Acute lens-related complications: traumatic cataract, lens-induced inflammation or angle closure can present with pain and visual loss.
- Leukocoria: white pupillary reflex in a child is urgent; congenital cataract, retinal disease and retinoblastoma must be excluded.
9. Extra-ocular movements and alignment
- Ask the patient to fixate on a target and follow it through the six cardinal positions.
- Observe smooth pursuit, range, pain, diplopia, nystagmus and compensatory head posture.
- Assess alignment with corneal light reflex and cover/uncover tests where trained.
- Acute painful restriction with fever/proptosis suggests orbital cellulitis; restriction after trauma may indicate fracture/entrapment.
- New diplopia with ptosis, anisocoria, severe headache or other neurological signs requires emergency evaluation.
10. Safe use of additional tests
| Test | Use | Do not / caution |
|---|---|---|
| Upper-lid eversion | Find subtarsal foreign body or assess tarsal conjunctiva. | Avoid force in suspected open globe or severe trauma; seek trained help. |
| Fluorescein | Detect epithelial defect, ulcer and Seidel leak. | Do not delay emergency irrigation or press a leaking globe. |
| Topical anaesthetic | Facilitate supervised examination or foreign-body removal. | Never prescribe for home use; toxicity and masking of deterioration. |
| Tonometry | Measure IOP in selected cases. | Contraindicated until open globe is excluded; interpret clinically. |
| Mydriasis | Permit fundus examination. | Do not dilate before assessing angle-closure risk, pupil/neurological status or trauma. |
| Slit lamp | Magnified optical-section examination. | Needs trained operator and patient cooperation; refer if unavailable and urgent disease suspected. |
11. Documentation template
Example
External exam: facial symmetry preserved; no proptosis or trauma. Lids appose, lashes away from cornea, no ptosis/entropion. Conjunctiva mildly injected without chemosis or discharge; sclera white. Cornea clear and lustrous without visible foreign body. Anterior chamber appears deep/quiet; iris pattern regular. Pupils equal/reactive, no RAPD. Lens clear on red reflex. EOM full and painless, no diplopia. Record VA and IOP only when safely obtained.
12. Emergency findings
- Full-thickness lid laceration, medial canthal injury, visible fat or tissue prolapse.
- Irregular/teardrop pupil, shallow anterior chamber, uveal prolapse or positive Seidel sign.
- Corneal infiltrate/ulcer, hypopyon, marked oedema or severe epithelial defect.
- Hyphema after trauma, severe pain with reduced vision or high-risk contact-lens keratitis.
- Proptosis, tense orbit, RAPD, reduced colour/vision or restricted painful movements.
- Acute anisocoria with ptosis/diplopia/headache or other neurological signs.
- Leukocoria or absent/asymmetric red reflex in a child.
13. Applied cases
Case 1: Corneal foreign body
A worker reports a metallic particle after grinding. Examine acuity and pupils, shield the eye, avoid pressure and do not remove an embedded object in an uncertain setting. Urgent slit-lamp assessment is needed to exclude penetration and rust-ring injury.
Case 2: Painful red eye with a small irregular pupil
Deep ache, photophobia, ciliary flush and an irregular pupil suggest anterior uveitis or traumatic iris damage rather than simple conjunctivitis. Measure VA and arrange urgent ophthalmic review; avoid unsupervised steroid or mydriatic drops.
Case 3: Fever and proptosis
A child has swollen lids, fever, proptosis and painful restricted movements. The external examination identifies an orbital emergency. Coordinate immediate admission, imaging and intravenous treatment.
14. Self-test
- What should be done before manipulating a painful eye?
- How does ciliary flush differ from diffuse conjunctival injection?
- Name four corneal findings that require urgent referral.
- What does a positive Seidel test indicate?
- When is tonometry unsafe?
- What can an irregular teardrop pupil after trauma indicate?
- Why is leukocoria in a child urgent?
- List the cranial nerves involved in eye movements.
- What should be recorded in a complete external examination?
- Why should an upper lid not be everted forcefully?
Answers
- Ask about trauma/chemical exposure, measure VA/pupils and assess for an open globe; stabilise and refer if suspected.
- Ciliary flush is deeper circumcorneal redness suggesting keratitis/uveitis/glaucoma; diffuse injection is usually superficial conjunctival disease.
- Ulcer/infiltrate, opacity/oedema, major epithelial defect, foreign body after high-velocity injury, neovascularisation or Seidel leak.
- Aqueous leakage through a full-thickness corneal/scleral wound.
- When penetrating/open-globe injury is possible.
- Open globe, iris prolapse or traumatic iris damage.
- It may signal congenital cataract, retinal disease or retinoblastoma and can threaten vision/life.
- CN III, IV and VI for extra-ocular movement; CN VII for eyelid closure.
- Orbit/globe position, lids/lashes, conjunctiva/sclera, cornea, chamber, iris/pupils, lens/red reflex, motility, VA and safe additional tests.
- It can worsen a wound or cause pressure on an open globe; use trained technique and seek help.
Key takeaways
- Examine from general appearance to lids, conjunctiva, cornea, chamber, iris, pupil, lens and motility.
- Compare eyes and document visual acuity before assuming a superficial diagnosis.
- Corneal opacity, ciliary flush, hypopyon, hyphema, abnormal pupil, proptosis and reduced vision change urgency.
- Never press a suspected open globe; shield and refer.
