Introduction to Ophthalmology • Ophthalmic symptomatology • Abnormal sensations
Abnormal Ocular Sensations: Pain, Dryness, Itching and Foreign-Body Sensation
Ocular sensation is generated by a richly innervated ocular surface and by deeper intraocular, orbital and neural structures. Pain, dryness, itching, burning and the feeling that something is in the eye are common complaints, but their urgency varies widely. A superficial irritant may be minor; a corneal ulcer, acute glaucoma, orbital infection, chemical injury or neurological process can threaten sight and life.
Emergency warning: Severe or deep eye pain, pain with reduced vision, photophobia, corneal opacity, contact-lens use, chemical/penetrating trauma, proptosis, fever, painful eye movements, fixed pupil, severe headache/vomiting or pain after surgery/injection requires urgent ophthalmic assessment.
Learning objectives
- Define pain, dryness, itching, burning, photophobia, foreign-body sensation and pain on movement.
- Use history and examination to separate ocular-surface, intraocular, orbital, neurological and referred causes.
- Recognise sight-threatening causes that can initially resemble “conjunctivitis” or irritation.
- Provide safe first aid, including irrigation and foreign-body precautions.
- Explain hospital assessment, treatment principles, prevention and patient education.
1. Understanding ocular sensation
| Sensation | Patient’s words | Possible anatomical source |
|---|---|---|
| Pain | Sharp, stabbing, aching, boring, throbbing or severe. | Corneal nerves, uvea, sclera, orbit, optic nerve, trigeminal pathways or referred structures. |
| Burning/stinging | “It burns,” “soap in my eye,” “hot or irritated.” | Tear-film/epithelial irritation, chemical exposure, allergy or topical medication. |
| Itching | “I want to rub it.” | Conjunctival allergy, lid-margin disease or dermatitis. |
| Dryness/grittiness | Sand, dust, tired or sticky eyes. | Tear-film instability, aqueous deficiency, meibomian disease, exposure or medication effect. |
| Foreign-body sensation | Something is stuck or scratching with blinking. | Corneal abrasion, subtarsal foreign body, conjunctival lesion, trichiasis or contact-lens complication. |
| Photophobia | Light is painful or intolerable. | Corneal/uveal inflammation, migraine, meningism or severe surface injury. |
| Pain on movement | Deep pain when looking around. | Optic neuritis, orbital inflammation, cellulitis, muscle or orbital trauma. |
2. Focused history
- Onset: exact time, sudden/gradual, exposure-related, recurrent or progressive.
- Site and depth: surface scratch versus deep ache behind the eye; unilateral or bilateral.
- Quality/severity: burning, itching, gritty, sharp, boring, pulsating; use a pain scale and functional impact.
- Triggers: blinking, eye movement, light, reading, screens, wind, smoke, contact lenses or a chemical.
- Associated visual symptoms: blur, reduced acuity, halos, flashes, floaters, field loss, diplopia or colour change.
- Inflammatory/systemic features: redness, discharge, fever, headache, nausea/vomiting, rash, joint pain, autoimmune disease or immunosuppression.
- Trauma and procedure: grinding/welding, high-velocity object, surgery, injection, foreign body, rubbing or recent anaesthesia.
- Contact lens history: overnight wear, water exposure, poor cleaning, replacement and current use.
- Medication history: drops, preservatives, steroids, glaucoma medicines, isotretinoin, antihistamines, anticholinergics and systemic drugs causing dryness.
- Past eye history: glaucoma, uveitis, corneal disease, herpes, surgery, one-eyed status or recurrent erosions.
3. Initial examination and safety
| Step | Key points | Danger if missed |
|---|---|---|
| Vital signs/systemic assessment | Temperature, blood pressure, mental status, glucose when indicated. | Sepsis, severe hypertension, meningitis or metabolic disease. |
| Visual acuity | Each eye separately with correction and pinhole if appropriate. | Reduced VA changes a “simple irritation” into an urgent problem. |
| Pupils/RAPD | Size, shape, reactivity and swinging-light response. | Optic-nerve/retinal disease, acute glaucoma or neurological pathology. |
| External exam | Lids, lashes, conjunctiva, ciliary flush, cornea, proptosis, discharge and trauma. | Ulcer, open globe, cellulitis, severe inflammation. |
| Motility | Movement limitation or pain, diplopia and nystagmus. | Orbital cellulitis, optic neuritis, fracture or cranial-nerve palsy. |
| Fluorescein/slit lamp | For epithelial defect, infiltrate, foreign body, cells/flare or Seidel leak when safe. | Corneal ulcer, penetrating injury or intraocular inflammation. |
| IOP | Only after open globe is excluded and trained staff/equipment are available. | Pressure on an open globe can worsen injury. |
4. Ocular pain
| Cause group | Examples | Typical clues |
|---|---|---|
| Corneal/surface | Abrasion, keratitis, ulcer, recurrent erosion, foreign body, chemical injury. | Severe pain, photophobia, tearing, blink-related discomfort, fluorescein defect or opacity. |
| Anterior intraocular | Anterior uveitis/iritis, acute angle-closure glaucoma. | Ciliary flush, photophobia, blurred vision, small/irregular or mid-dilated pupil, cells/flare or high IOP. |
| Deep ocular coat | Scleritis, posterior uveitis. | Deep boring pain, tenderness, pain with movement or autoimmune disease. |
| Orbital | Orbital cellulitis, abscess, haemorrhage, fracture, tumour or thyroid eye disease. | Proptosis, restricted/painful movement, fever, diplopia or optic-nerve signs. |
| Optic nerve | Optic neuritis, ischaemic or compressive optic neuropathy. | Reduced colour/central vision, RAPD, pain on movement or field loss. |
| Neurological/referred | Migraine, trigeminal neuralgia, cluster headache, sinus disease, meningitis. | Headache pattern, neurological or systemic signs; ocular examination may be normal. |
Corneal pain is often intense because the epithelium is supplied by trigeminal sensory fibres. Deep pain with reduced vision, a quiet-looking eye and RAPD is not reassuring; optic-nerve or orbital disease may be hidden behind the globe.
5. Dryness, burning and grittiness
Dry-eye disease occurs when tear-film homeostasis fails. The problem may be insufficient aqueous production, excessive evaporation, poor lipid secretion, abnormal mucin/surface interaction, inflammation or exposure.
| Mechanism | Examples | Associated clues |
|---|---|---|
| Aqueous deficiency | Sjögren syndrome, lacrimal-gland disease, age-related reduction, systemic medicines. | Persistent dryness, foreign-body sensation, reduced tear meniscus. |
| Evaporative loss | Meibomian-gland dysfunction, blepharitis, wind, smoke, screens and incomplete blinking. | Fluctuating blur, lid crusting, oily tear film or worse late in the day. |
| Exposure | Lagophthalmos, facial-nerve palsy, proptosis, intensive-care sedation. | Inferior staining, nocturnal symptoms and risk of exposure keratopathy. |
| Surface toxicity/inflammation | Preserved drops, allergy, chronic topical medicines, chemical irritation. | Burning after drops, redness and worsening with frequent self-medication. |
Safe management principles
- Remove smoke, dust, wind and avoid prolonged uninterrupted screen viewing; encourage regular blinking and breaks.
- Use preservative-free lubricants when frequent treatment is required and follow local product guidance.
- Treat lid-margin disease with warm compresses and gentle hygiene when appropriate; avoid squeezing lesions.
- Assess exposure, facial weakness, contact lenses, autoimmune symptoms and medication causes.
- Refer urgently when pain, photophobia, reduced vision, corneal opacity or contact-lens use is present.
6. Itching and rubbing
Itching strongly suggests ocular allergy, but rubbing can worsen epithelial injury, spread infection and contribute to keratoconus in susceptible people. Allergic conjunctivitis often causes bilateral itching, watering, chemosis and stringy mucus; it should not cause severe pain or marked visual loss.
- Ask about seasonal exposure, dust, cosmetics, pets, atopy, asthma, eczema and new medicines.
- Use cool compresses, allergen reduction and clinician-directed topical anti-allergic therapy when indicated.
- Avoid sharing towels or drops; wash hands and avoid rubbing.
- Severe unilateral pain, photophobia, reduced vision, corneal opacity or contact-lens use requires an alternative diagnosis and urgent assessment.
7. Foreign-body sensation
| Cause | Clues | Initial action |
|---|---|---|
| Loose superficial particle | Sudden gritty feeling, tearing; may be visible on conjunctiva. | Do not rub; irrigate gently and seek assessment if persistent. |
| Subtarsal foreign body | Scratch on every blink; upper-lid eversion may reveal it. | Trained examiner may inspect/irrigate; refer if embedded or uncertain. |
| Corneal foreign body | Focal pain, photophobia, visible spot or rust ring. | No rubbing or home removal; urgent trained removal and fluorescein assessment. |
| High-velocity/intraocular foreign body | Grinding/hammering, tiny entry wound, decreased vision or irregular pupil. | Rigid shield, no pressure/tonometry, urgent imaging and ophthalmic referral. |
| Trichiasis/entropion | Recurrent localised scratch despite no particle. | Examine lid margin and cornea; treat underlying lid disorder. |
| Contact-lens complication | Lens stuck, pain, redness, photophobia or reduced vision. | Remove only if easy; no lens reinsertion; urgent review for keratitis. |
8. Abnormal sensations that are emergencies
Chemical injury
Alkali and acid can cause epithelial loss, stromal damage, limbal ischaemia and later scarring. Begin copious irrigation immediately with clean water/saline, remove accessible contact lenses, continue according to protocol, then obtain urgent ophthalmic assessment. Never delay irrigation for a full history, pH measurement or transport.
Contact-lens keratitis
Pain, photophobia, redness and reduced vision in a contact-lens wearer may represent a rapidly progressive corneal infection. Remove lenses, avoid patching and unsupervised steroids, and arrange urgent specialist-directed antimicrobial care.
Acute angle closure
Severe pain, halos, red eye, blurred vision, headache, nausea/vomiting and a mid-dilated pupil suggest acute pressure elevation. Avoid mydriasis and urgent delay; involve ophthalmology immediately.
Orbital cellulitis
Fever, proptosis, painful/restricted movements, reduced vision or RAPD indicate postseptal disease until excluded. Treat as an emergency because infection can threaten the optic nerve and spread intracranially.
9. First aid and hospital management
- Stabilise and protect: assess life threats, prevent rubbing and use eye protection during transport.
- Irrigate chemicals: start immediately; use copious clean water/saline, remove lenses if easy and continue until directed by protocol. Check pH after initial irrigation if available; do not neutralise with another chemical.
- Open-globe precautions: no pressure, no tight patch, no forced lid opening, no tonometry and no removal of embedded material. Use a rigid shield and urgent referral.
- Foreign body: do not allow home instruments or magnets in the eye. High-velocity injuries need imaging/specialist management.
- Contact lens: remove and retain for assessment if infection is suspected; do not reinsert.
- Analgesia and antiemetics: use facility protocol; vomiting increases pressure and discomfort in some injuries.
- Specialist care: slit lamp, fluorescein, IOP (when safe), dilated exam, cultures, imaging and cause-directed medication or surgery.
Medication principles
- Lubricants may help uncomplicated dryness after examination, but a painful red eye with reduced vision should not be treated as dry eye alone.
- Topical antibiotic, antiviral, anti-inflammatory, cycloplegic or pressure-lowering treatment should follow examination and specialist/local protocol.
- Topical anaesthetic is for supervised examination only; repeated home use delays epithelial healing and can cause toxicity.
- Topical steroids can worsen herpetic, fungal or bacterial infection and should never be started for an undiagnosed red, painful eye.
- Review preservatives and systemic medicines when symptoms are chronic or bilateral; do not stop essential systemic therapy without the prescriber.
10. Prevention and patient education
- Wear certified protective eyewear for grinding, drilling, chemicals, welding and high-velocity work.
- Use contact lenses exactly as prescribed; avoid overnight wear and water exposure unless approved, maintain hand hygiene and replace lenses/cases on schedule.
- Manage diabetes, hypertension, autoimmune disease and skin/lid disease; attend eye reviews when indicated.
- Use breaks, blinking, suitable lighting and humidification for prolonged screen or close work.
- Keep household chemicals in labelled containers, never decant them into drink bottles and know the first-aid/poison-control plan.
- Seek urgent care for reduced vision, photophobia, severe pain, new floaters/flashes, fever/proptosis, vomiting or worsening after treatment.
11. Applied cases
Case 1: “Dust in my eye” after grinding
A worker has severe pain, photophobia and reduced vision after grinding metal. Treat as a possible high-velocity corneal/intraocular foreign body. Shield the eye, avoid pressure, do not attempt removal or tonometry, document acuity/pupils and arrange urgent ophthalmic assessment.
Case 2: Itching in both eyes
A student has bilateral itching, watery eyes and a history of eczema but normal acuity and no pain. Allergy is likely. Reduce exposure, use cool compresses and clinician-directed anti-allergic treatment, while giving return precautions for pain, photophobia or visual decline.
Case 3: Painful red eye in a lens wearer
A contact-lens wearer reports worsening pain, photophobia and blur. A corneal ulcer is possible even if discharge is small. Remove the lens, avoid steroid drops/patching and arrange urgent same-day specialist review.
Case 4: Severe pain with vomiting
A patient with a red eye, blurred vision, halos and vomiting may have acute angle closure. Keep the patient monitored, avoid mydriatic drops and seek immediate ophthalmology management.
12. Self-test
- Why can a corneal abrasion be extremely painful?
- What symptom combination makes contact-lens discomfort an emergency?
- List four causes of dry, gritty eyes.
- What is the safe first action after a chemical splash?
- When should pressure on the globe and tonometry be avoided?
- Why is itching more suggestive of allergy than pain?
- Name three causes of deep eye pain.
- What findings suggest orbital rather than preseptal disease?
- Why are home topical anaesthetic drops unsafe?
- Why can steroid eye drops worsen an undiagnosed red eye?
Answers
- The corneal epithelium has dense trigeminal sensory innervation and is stimulated with every blink.
- Pain, photophobia, redness or reduced vision—especially with overnight wear or poor hygiene—suggests keratitis/corneal ulcer.
- Aqueous deficiency, meibomian dysfunction, exposure, preserved-drop toxicity, allergy, screen/wind/smoke exposure and medication effects.
- Immediate copious irrigation; do not delay for a detailed history.
- When penetrating/open-globe injury is suspected.
- Histamine-mediated conjunctival/lid inflammation commonly causes itching; severe pain suggests corneal, intraocular, orbital or neurological pathology.
- Scleritis, uveitis, acute glaucoma, orbital cellulitis, optic neuritis or referred neurological pain.
- Proptosis, painful/restricted movements, reduced vision, RAPD, fever or systemic toxicity.
- They mask deterioration, are toxic to epithelium and delay healing; repeated unsupervised use can cause serious damage.
- They can worsen herpetic/fungal/bacterial infection and delay epithelial healing.
Key takeaways
- Pain, itching and dryness are not interchangeable; their quality and associated visual signs guide urgency.
- Contact-lens pain, chemical injury, foreign body after high-velocity work and painful red eye with reduced vision are emergencies.
- Irrigate chemical injury immediately; shield suspected open globe and never press on it.
- Use eye drops only for a clear indication and appropriate protocol; steroid and anaesthetic misuse can cost vision.
