Ophthalmology
Conjunctiva and the Red Eye
Conjunctiva for MBBS and NEET-PG: red eye approach, bacterial, viral and allergic conjunctivitis, trachoma and SAFE, vernal catarrh and pterygium, mapped to NMC codes OP3.
MedNext Academy | 3 min read
Conjunctiva and the Red Eye
Conjunctiva for MBBS and NEET-PG: red eye approach, bacterial, viral and allergic conjunctivitis, trachoma and SAFE, vernal catarrh and pterygium, mapped to NMC codes OP3.
This chapter frames the approach to the red eye, sorting the benign from the sight-threatening by pain, vision and discharge. It details the conjunctivitides, the public health disease trachoma and its SAFE strategy, allergic vernal disease, and the degenerations such as pterygium, alongside the practical skills of drop instillation and foreign body removal.
High-yield: Conjunctiva and the Red Eye
- A red eye with normal vision, itching or discharge and no pain usually points to conjunctivitis, whereas a painful red eye with reduced vision suggests a serious cause such as keratitis, uveitis or acute glaucoma.
- Bacterial conjunctivitis gives a purulent, sticky discharge with lids matted on waking, while viral conjunctivitis gives a watery discharge with follicles and a preauricular node.
- Allergic conjunctivitis is dominated by itching and a stringy, ropy mucoid discharge with papillae on the tarsal conjunctiva.
- Ophthalmia neonatorum within the first 48 hours of life suggests gonococcal infection, which is hyperacute and can perforate the cornea, and requires urgent systemic treatment.
- Trachoma is a chronic keratoconjunctivitis caused by Chlamydia trachomatis serotypes A to C and is a leading infective cause of blindness worldwide.
- The SAFE strategy for trachoma control is Surgery for trichiasis, Antibiotics with azithromycin, Facial cleanliness and Environmental improvement.
- Trachoma scarring produces Arlt's line on the upper tarsal conjunctiva, and healed limbal follicles leave Herbert's pits.
- Vernal keratoconjunctivitis is a seasonal allergic disease of young boys with giant cobblestone papillae on the upper tarsus and limbal Horner-Trantas dots.
- A pterygium is a triangular fibrovascular growth of conjunctiva onto the cornea, related to ultraviolet exposure, and is excised when it threatens the visual axis.
- A pinguecula is a yellowish conjunctival deposit that, unlike a pterygium, does not encroach onto the cornea.
- Symblepharon is adhesion of the palpebral to the bulbar conjunctiva, seen after chemical burns and Stevens-Johnson syndrome.
- Subconjunctival haemorrhage is a painless, flat, bright red patch with normal vision that resolves spontaneously and needs only reassurance.
- Correct eye-drop instillation is into the lower fornix with the head tilted back, followed by punctal occlusion to reduce systemic absorption.
- A superficial conjunctival foreign body is removed after topical anaesthesia, everting the upper lid to inspect the subtarsal sulcus where foreign bodies lodge.
Types of conjunctivitis
- **Bacterial:** Purulent sticky discharge, lids matted on waking. Topical antibiotics.
- **Viral:** Watery discharge, follicles, preauricular node. Highly contagious, supportive care.
- **Allergic:** Itching, ropy mucoid discharge, tarsal papillae. Antihistamine and mast-cell stabiliser.
- **Trachoma:** Chlamydia trachomatis A to C. Arlt's line, trichiasis. SAFE strategy.
NMC competencies in this chapter
- **OP3.1:** History in a patient with a red eye
- **OP3.2:** Examination of a patient with a red eye
- **OP3.3:** Conjunctivitis: types, features and treatment
- **OP3.4:** Trachoma and its control
- **OP3.5:** Vernal keratoconjunctivitis
- **OP3.6:** Pterygium
- **OP3.7:** Symblepharon
- **OP3.9:** Eye drop instillation technique
Frequently Asked Questions
How do you distinguish a dangerous red eye from a benign one?
A painful red eye with reduced vision, photophobia or an abnormal pupil suggests a serious cause like keratitis, uveitis or acute glaucoma. A red eye with normal vision, itching or discharge is usually benign conjunctivitis.
What is the SAFE strategy for trachoma?
It is the World Health Organization control programme: Surgery for trichiasis, Antibiotics with azithromycin, Facial cleanliness and Environmental improvement to reduce transmission.
What is the difference between a pterygium and a pinguecula?
A pterygium is a triangular fibrovascular growth that encroaches onto the cornea and can affect vision, while a pinguecula is a yellowish conjunctival deposit that stays off the cornea.
Which conjunctivitis causes ophthalmia neonatorum in the first 48 hours?
Discharge within the first 48 hours of life suggests gonococcal ophthalmia neonatorum, which is hyperacute and can perforate the cornea, so it needs urgent systemic treatment.
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