1.1 Anterior Segment Examination

Examination Outline

Examination Structure

Attention should be given to the wording of the question which often directs the candidate where to look:

“Examine the”…

  1. External Eye – Periorbital tissue, eyelid, margins, conjunctiva, fornices, limbus and corneal surface
  2. Anterior Segment – Eyelids, conjunctiva, cornea (all layers), anterior chamber, iris and lens

1. Visual Acuity, IOP, Inspection, ± Refraction

Always stand back and examine the patient as a whole. Age / gender / ethnicity are often useful in narrowing the potential differential diagnoses. Iris heterochromia, symblephara, ankyloblepharon and forniceal shortening are often more obvious on gross inspection before beginning the slit lamp examination.

2. Lid, Lashes, Lacrimal Structures

  • Blepharitis,
  • Ectropion / entropion / punctum
  • Madarosis / hypertrichiasis
  • Scarring from HZO / pigment changes

3. Conjunctiva/Sclera

  • Ask the patient to ‘Look up’ (while pulling the lower lid down): Symblepharon / ankyloblepharon / forniceal shortening
  • Ask the patient to ‘Look down’ (while pulling the upper lid up): Trabeculectomy bleb / glaucoma drainage device
  • Scleral buckle
  • Offer to evert the upper lid

4. Cornea

  • Always mark the visual axis.
  • Always draw a cross-section with corneal epithelium / stroma / endothelium, iris and lens (Figure 1.1.1). It is important to document the level, size, shape and location of any corneal lesion.


  1. Shape: e.g. Keratoconus
  2. Size: Measure the corneal diameter with a handheld ruler if suspicious of congenital glaucoma. Greater than 12mm in an adult is abnormal, Microcornea is defined as corneal diameter <10mm
  3. Thinning: Estimate and document the remaining thickness as a % of normal
  4. Scars, wounds
  5. Corneal graft
    i. Type (penetrating vs. anterior lamellar vs. endothelial)? Size? Clarity?
    ii. Sutures? (interrupted, continuous, broken / loose?)
    iii. Pay special attention to the graft-host junction
    iv. Neovascularisation?
    v. Look at the other eye for clues as to why the patient had a graft
  6. ± Tear film / marginal tear strip

In addition, look at each corneal layer:

  1. Epithelium: Epithelial defects, punctate epithelial erosions, superficial punctate keratitis, dystrophies, microcystic oedema, Fleischer ring, limbal stem cell failure (conjunctivalisation of the cornea)
  2. Stroma: Dystrophies, stromal oedema, vessels (superficial or deep?), prominent corneal nerves
  3. Endothelium: Guttata, pigment dispersion, keratic precipitates (KP), Descemet’s membrane folds

The presence of one sign (e.g. a conical cornea) should prompt you to look for other associated signs of that condition (e.g. Down syndrome, vernal kerato-conjunctivitis, Fleischer ring- best seen with cobalt blue light, prominent corneal nerves, hydrops / corneal scarring and Vogt striae of keratoconus).

If an ocular surface mass is present (e.g. Ocular surface squamous neoplasia), you must exclude orbital invasion. Check for:

  • Lymphadenopathy
  • Corneal sensation
  • Ophthalmoplegia
  • Intraocular examination including gonioscopy for angle involvement

5. Anterior Chamber

  • Cells / flare
  • Hypopyon, hyphaema
  • Anterior chamber depth (narrow angle?). Von Herrick’s test can estimate angle depth

If an intraocular mass is present (e.g. iris melanoma), then check for:

  • Hyphaema
  • Nodular vs diffuse configuration
  • Ectropion uveae – seen in iris melanoma
  • Refractory glaucoma - raised IOP
  • Gonioscopy for angle involvement
  • Transillumination – more likely to be a cyst
  • Subjacent ciliary body involvement – will need eye to be dilated
  • Dilated fundus examination for extension posteriorly

6. Pupil

  • Round (trauma, posterior synechiae, vermiform movements)
  • Ectropion uveae (may be suggestive of prior rubeosis iridis)
  • Pseudoexfoliation (PXF)

7. Iris

  • Posterior bow (pigment dispersion syndrome PDS)
  • Rubeosis (neovascular vessels run parallel to pupil rather than radially and are uncuffed)
  • Transillumination defects: Peripheral iridotomy (PI), PXF, PDS, HZO, trauma (IOL, ACG)


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