Differential Diagnosis: The “Red Eye”
Ophthalmology High-Yield Examination Essentials
1. Clinical Comparison
| Condition | Key Symptoms | Key Signs |
|---|---|---|
| Conjunctivitis | Grittiness, discharge. | Conjunctival injection, discharge. |
| Acute Iritis | Deep ache, photophobia. | Ciliary flush, cells/flare in AC. |
| Acute Glaucoma | Severe pain, halos, nausea. | Fixed mid-dilated pupil, high IOP. |
| Keratitis | Pain, photophobia, blurred vision. | Corneal infiltrate/stain. |
2. NEET PG High-Yield Pearls
- Ciliary Flush vs. Conjunctival Hyperemia: Ciliary flush (circumcorneal injection) indicates serious intraocular/corneal pathology; conjunctival hyperemia is common in simple conjunctivitis.
- Vision Check: Always record visual acuity. If vision is significantly reduced, the red eye is likely not simple conjunctivitis.
- Pupil Assessment: A fixed, mid-dilated pupil in the presence of a painful red eye is a hallmark of acute angle-closure glaucoma.
- The “Danger” List: Any red eye associated with severe pain, photophobia, vision loss, or a fixed pupil requires urgent referral.