What are the contraindications of fundus examination?

Contraindications of Fundus Examination

There are no absolute contraindications to fundus examination itself; however, pupillary dilation (mydriasis) required for optimal fundus visualization has specific contraindications, and certain clinical scenarios require urgent evaluation before routine examination.

Contraindications to Pupillary Dilation

Absolute Contraindications

• Hypersensitivity to mydriatic agents is an absolute contraindication to pharmacologic pupillary dilation 1
• Acute angle-closure glaucoma or suspected angle-closure crisis with mid-dilated, oval, or asymmetric pupil requires immediate management with gonioscopy and IOP-lowering therapy rather than dilation 2
• Narrow angles with evidence of pupillary block should not undergo dilation without prior assessment and consideration of prophylactic laser iridotomy 3

Relative Contraindications Requiring Urgent Evaluation First

• New-onset pupil-involving third nerve palsy requires immediate neuroimaging (MRI with gadolinium and MRA or CTA) to rule out posterior communicating artery aneurysm before any routine examination 2
• Anisocoria with headache, altered mental status, or other neurological deficits necessitates urgent neurological evaluation before dilation 2
• Anisocoria following head trauma requires urgent assessment for intracranial bleeding before routine fundus examination 2
• Suspected intracranial bleeding with pupillary changes (dilated fixed pupils suggesting increased ICP or impending herniation) requires urgent neuroimaging and neurosurgical consultation before any elective procedures 4

Clinical Scenarios Where Dilation May Be Deferred

When Undilated Examination Is Sufficient

• Direct ophthalmoscopy can detect most clinically significant fundus lesions in asymptomatic patients, with only 0.274% of significant findings located beyond the view of routine direct ophthalmoscopy 5
• Non-mydriatic fundus photography demonstrates high sensitivity (94.8-96.3%) and specificity (97.8-98.5%) for detecting glaucomatous optic disc changes compared to dilated examination 6

Patient-Specific Considerations

• Significant macular disease with central photoreceptor loss may be a contraindication to certain screening procedures (visual fields, OCT, fundus autofluorescence) as it interferes with test interpretation, though this relates to testing rather than examination itself 3
• Isolated drusen that leave good visual fields and intact photoreceptor structure should not interfere with screening and are not contraindications 3

Important Clinical Pearls

The preferred technique for optic nerve head evaluation involves magnified stereoscopic visualization through a dilated pupil whenever feasible 3. However, when dilation is contraindicated or not feasible:

• Red-free illumination may aid in evaluating the retinal nerve fiber layer without dilation 3
• Direct ophthalmoscopy provides greater magnification and can complement undilated examination 3
• Computer-based imaging and non-mydriatic photography offer alternative documentation methods 3, 6

Critical Pitfall to Avoid

Never dilate pupils in patients with acute neurological signs without first ruling out life-threatening conditions such as posterior communicating artery aneurysm or intracranial bleeding, as pupillary examination is essential for monitoring these conditions 4, 2. Dilating these pupils could mask critical clinical signs of deterioration.