Hertel Exophthalmometry — Proptosis Assessment
Hertel readings measure axial globe position (lateral orbital rim → corneal apex). Caucasian adult normal 12–22 mm; ≥2 mm asymmetry is significant. Higher in African and Asian populations. Used in thyroid eye disease, orbital tumour, cellulitis, and post-trauma evaluation.
Score interpretation
→ No oculoplastic concern from this measurement alone. Document baseline if at risk (Graves', familial).
→ TFTs + TRAb if no diagnosed thyroid disease. CT or MRI orbits if unilateral or rapidly progressive. Monitor with serial Hertel.
→ Urgent oculoplastic / thyroid-eye-disease referral (RCOphth standards: <2 weeks). MRI orbits with fat suppression. Assess optic nerve function (acuity, colour vision, RAPD). Consider teprotumumab / IV methylprednisolone in active TED.
→ Same-day ophthalmology and endocrinology. MRI orbits to exclude compressive optic neuropathy or apex tumour. IV methylprednisolone 500 mg daily ×3 if dysthyroid optic neuropathy; orbital decompression if no response or globe subluxation. Consider biopsy if mass lesion suspected.
Interpretation bands for the Hertel. Apply clinical judgement and local guidance.
References
Related
Curated clinical cross-links plus same-class fallbacks.
- Acute Red Eye / Vision Loss Screen · RCOphth 2020; NICE CKS
- Idiopathic Intracranial Hypertension · ABN; consensus 2018
- Acute Red Eye Assessment · RCOphth / AAO
- Acute Angle Closure Glaucoma · RCOphth / EGS Guidelines
- Retinal Detachment · RCOphth Guidelines / EURETINA
- Diabetic Retinopathy — Screening and Management · NICE NG28 2016 / NHS DES Programme
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.