Confusers in Ophthalmology: 17 Look-Alike Terms Explained
Last updated: October 2026
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- 20 look-alike disease pairs compared
- This page: 17 look-alike terms explained
Pairs of terms that sound alike but mean different things. Each table puts the two side by side so the difference sticks.
Lens-induced disease
| Term | Mechanism | Key feature |
|---|---|---|
| Phacolytic glaucoma | Lens proteins leak through an intact capsule of a hypermature cataract and clog the meshwork | Open angle, deep AC with white particles |
| Phacoanaphylactic (phacoantigenic) uveitis | Granulomatous immune reaction to lens protein after capsule rupture | Follows trauma or retained lens matter |
| Phacomorphic glaucoma | Swollen intumescent lens closes the angle | Shallow AC in that eye only |
Look-alike terms
| Term A | Term B | Difference |
|---|---|---|
| Epithelial downgrowth | Epithelial ingrowth | Downgrowth: epithelium grows into the anterior chamber after surgery or trauma. Ingrowth: epithelium grows under a LASIK flap |
| Heterochromia iridis | Heterochromia iridum | Iridis: two colours within one iris (sectoral). Iridum: the two irides differ in colour |
| Dystopia | Hypotropia | Dystopia: the whole globe is displaced vertically (orbital). Hypotropia: the visual axis points down, the globe is not displaced |
| Lid lag | von Graefe sign | Lid lag: static, the upper lid sits high in downgaze. von Graefe: dynamic, the lid lags as the eye moves down |
| Lagophthalmos | Lid retraction | Lagophthalmos: incomplete lid closure. Retraction: the open lid sits too high |
| Xanthoma | Lipogranuloma | Xanthoma: lipid inside cells (xanthelasma is one type). Lipogranuloma: extracellular lipid with granulomatous reaction |
| Retinal dialysis | Giant retinal tear | Dialysis: disinsertion at the ora with vitreous on the posterior edge. Giant tear: 90° or more, vitreous on the anterior edge, flap can roll |
| Mixed-mechanism angle closure | Combined-mechanism glaucoma | Mixed: pupil block plus non-pupil-block (e.g. plateau) closure. Combined: angle closure plus open-angle elements |
| Atropinic mydriasis | Adrenergic mydriasis | Atropinic: whole sphincter paralysed, no response to pilocarpine, accommodation lost. Adrenergic: very large pupil, blanched conjunctiva, wide fissure, accommodation spared, bright light partly overcomes it |
| Autofluorescence | Pseudofluorescence | Autofluorescence: a structure fluoresces by itself before dye (disc drusen, astrocytic hamartoma). Pseudofluorescence: an artefact from mismatched exciter and barrier filters |
| Fluorescence | Phosphorescence | Both are luminescence (light not caused by heat). Fluorescence stops when excitation stops; phosphorescence continues afterwards. Light from heat is incandescence |
| Episcleritis | Scleritis | Episcleritis: mild, vessels blanch with phenylephrine. Scleritis: severe boring pain, deep vessels do not blanch |
| Papilloedema | Papillitis | Papilloedema: disc swelling from raised intracranial pressure, vision preserved early. Papillitis: inflammatory disc swelling with early visual loss and RAPD |
| Pseudoexfoliation | True exfoliation | Pseudo: fibrillar deposits on the lens and angle (PXF). True: splitting of the anterior capsule from infrared (glassblowers) |
Related: Triads in ophthalmology, Pathognomonic signs, Eponymous signs.
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