Calibrate your screen first
Hold a credit card or driver’s license against the screen with its short edge along the bar. Drag until the bar is exactly as long as the card is tall (54 mm). Everything below uses this to draw true-size targets.
Near card
Hold the screen at the test distance. Cover one eye. The patient points the way the legs of each E point. Record the smallest line where they get more than half right, with readers or a pinhole if they have them. Tap a line to reshuffle it.
A screening aid, not a validated acuity chart. Use a printed card when one is available. Lines marked in grey are near the limit of what your screen can draw sharply.
Pupil gauge
Hold beside the patient’s eye and match each pupil to the nearest circle. Measure in bright light and again in a dim room when the sizes differ.
Red desaturation
Show the red disc to each eye in turn. Ask whether the red looks equally bright. If one eye sees it washed out or pinkish, ask how red it looks compared with the good eye (e.g. “60%”). Asymmetry suggests optic nerve disease.
OKN strip
Moving stripes trigger optokinetic nystagmus, a reflex that needs some working vision. If a patient reports no light perception but their eyes track the stripes, some vision is present. Hold it about 50 cm away and watch the eyes.
Don’t, before ophtho sees them
- Don’t dilate.The pupil exam is a neuro vital sign, and dilating drops can trigger angle closure. Ask first.
- Don’t patch a possible open globe.Use a rigid shield that rests on bone. Don’t patch a contact lens wearer’s abrasion either; it raises infection risk.
- Don’t press on an injured eye.No forcing swollen lids open, no tonometry, and no removing impaled objects if an open globe is possible.
- Don’t send topical anesthetic home.Repeated use melts the cornea.
- Don’t start steroid drops blind.Without a slit lamp exam, they can worsen herpes or fungal keratitis and raise eye pressure.
- Don’t wait on ophtho to start the clock-sensitive work.Stroke workup for a suspected CRAO and irrigation for a chemical injury start before the page is answered.
Usually fine for clinic follow-up
When vision is normal and there is no pain, photophobia, or contact lens use:
- Viral or allergic conjunctivitis
- Subconjunctival hemorrhage without trauma (check BP, and INR if on warfarin)
- Stye or chalazion
- Chronic, stable vision loss
- Dry eye
- Diabetic retinopathy screening in a stable patient
New flashes and floaters are the exception: they still need a dilated exam within days, even when everything else looks fine.
Speak the language
| Term | Meaning |
|---|---|
| OD / OS / OU | Right eye / left eye / both eyes |
| cc / sc / PH | With correction / without / through a pinhole |
| CF / HM | Counts fingers / sees hand motion |
| LP / NLP | Light perception / no light perception |
| RAPD | Relative afferent pupillary defect, found with the swinging flashlight test |
| IOP | Intraocular pressure, normally about 10–21 mmHg |
| EOM | Extraocular movements |
| CVF | Confrontation visual fields |
| AC | Anterior chamber, the space between cornea and iris |
| SLE / DFE | Slit lamp exam / dilated fundus exam |
Eye drop cap colors
Topical eye drops follow a standard cap color code, which helps identify what a patient is using when they can’t name it.
A red cap in a neuro-check patient’s bag is worth asking about: it may explain a dilated pupil.
Sources
- Mac Grory B, et al. Management of central retinal artery occlusion: a scientific statement from the American Heart Association. Stroke. 2021. doi.org/10.1161/STR.0000000000000366
- Pappas PG, et al. Clinical practice guideline for the management of candidiasis: 2016 update by the IDSA. Clin Infect Dis. 2016. doi.org/10.1093/cid/civ933
- Hollands H, et al. Acute-onset floaters and flashes: is this patient at risk for retinal detachment? JAMA. 2009. doi.org/10.1001/jama.2009.1714
- American Academy of Ophthalmology. Color codes for topical ocular medications (policy statement).