Let's have a general overview of conjunctivitis along with the relevant anatomy, histology, physiology, and microbiology. Also, differentials of RED EYE & DRY EYE are mentioned.

1. RED EYE

2. Differentials of red eye
Based on site of disease
 Ocular surface
• Episcleritis/scleritis
• Conjunctivitis
• Subconjunctival hemorrhage
• Corneal ulcer
• Photokeratitis
• Allergy, Dry eye
 Intraocular
• Anterior uveitis (Iritis/iridocyclitis)
• Acute angle closure glaucoma
 Ocular adnexa
• Hordeolum
• Carotid-cavernous sinus fistula
Frings, A., Geerling, G., & Schargus, M. (2017). Red Eye: A Guide for Nonspecialists. Deutsches Arzteblatt
international, 114(17), 302–312. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5443986/

3. Overview of
Conjunctivitis

4. Anatomy

6. Anatomy

7. Histology

8. Physiology

10. Microbiology
• Non-pathogenic commensal, normally present
Staphylococcus albus or epidermidis, diphtheroids,
Propionibacterium acnes, Neisseria catarrhalis,
Corynebacterium xerosis
• Staphylococci are often found & relatively innocuous in the
absence of other organisms but play an important part in
mixed infections
• Streptococci, E. coli, B. proteus, N. gonorrhoeae,
H. aegyptius, Moraxella, etc. are pathogenic and
rarely found in normal eyes

12. Clinical signs of conjunctivitis
• Hyperemia / redness of conjunctiva
• Chemosis (conjunctival edema d/t exudation from abnormally permeable
capillaries)
• Conjunctival discharge
• FB sensation/grittiness
• Conjunctival inflammatory reaction
• Follicle (d/t localized aggregation of lymphocytes in subepithelial adenoid
layer of conjunctiva)
• Papillae (hyperplasia of normal vascular system growing into epithelium)
• Granuloma (inflammatory tissue d/t chronic irritation)
• Subconjunctival hemorrhage

19. References
• Parson’s disease of the eye
• A K Khurana, Comprehensive Ophthalmology
• Oxford Handbook of Ophthalmology