Before diving into the essentials of a physical exam, a quick review from last month. A thorough history taking from your patient may sound something like:

Example of a systematic history:

Hello, my name is Corey one of the med students working with the ophthalmology team. Which eye is bugging you? What are you noticing in that eye specifically - entire field loss/blurriness or part of the vision missing and where? Has the other eye had any problems? When did this all start? Has this happened before? What were you doing when it started? Has it been getting worse or has it been stable? Any other symptoms (pain, photophobia, headache, dizziness, peripheral neurological changes)? Medications changes? PMHx FHx and on and on. 

If that makes sense, then read on to learn about the physical exam. If it doesn’t make sense, then maybe read last month's post on taking a systematic history. If it still doesn’t make sense after reading last month’s post, maybe take a nap. Don’t sleep on…well… sleep in this case I suppose.

Physical Exam

Three things are essential to measure: vision, pupils, and pressure (THE EYE VITALS). Even outside of your ophthalmology elective, if you are working with a team that wants to consult ophthalmology, these are three things you MUST measure to help the consult: vision, pupils, and pressure. 

Pro Tip: Some also consider extraocular movements and confrontational visual fields as the remaining eye vitals. Be prepared to tell the consultant your findings with these too.

These are also the three things you must measure before dilating the eyes. Dilation can skew near vision, pupil assessment, and pressure measurements, and can even be dangerous if you haven’t checked the pressure first. 

1. Vision

Vision conventionally means visual acuity, but to help me remember I stack some extra things into vision: acuity (central vision), confrontational field (peripheral vision), ocular motility & alignment (resting and moving vision), and color vision (neurological vision). 

Visual Acuity (distance central vision): Recorded as 20/XX for each eye. If they can't see the big "E" (20/200), you can still quantify their visual acuity, and move down the chain:

• CF-X: Count fingers at X feet.
• HM-X: Detect hand motion at X feet.
• LP: Light perception.
• NLP: No light perception.

Confrontational Visual Fields: Test the four quadrants. This relies on intense eye contact, bonus points if you have dreamy eyes. Sit 1 metre away from the patient, who is occluding one eye, close your opposite eye (patient closes right eye, you close left eye). Get them to look deeply into your open eye, asking them to not break eye contact or cheat. Ideally, you and the patient should be able to count fingers in each of the 4 quadrants of both eyes (See below). Ensure you hold your hand about midway as they count your fingers.

Extraocular Alignment and Movements

Starting with alignment, determine if there is asymmetry in alignment between the two eyes. Then have the patient follow your finger in the 6 cardinal positions of gaze (see below). Also, note any diplopia and pain due to looking in any of the cardinal positions.

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Don’t worry about the acronyms for now, but know that the 6 cardinal positions of gaze can help pinpoint specific muscles and nerves on both eyes.

Colour Vision

Using pseudoisochromatic plates, such as the Ishihara plates, record the fraction of plates the patient correctly identifies (e.g., 10/17). Plate instructions may also indicate the potential colour defect. 

2. Pupils: PERRLA-DC

Checking to ensure the  Pupils are Equal and Round in a lit and dim room, as well as Reactive to Light and Accommodation-Direct and Consensual in a dim room.

• Reacting to Light = constricts with light
• Reacting to Accommodation = constricts when an object is brought close to the eye
• Direct = constricts in the pupil being tested
• Consensual = constricts in the pupil not being tested

The RAPD (Relative Afferent Pupillary Defect): Light should make pupils constrict, and if shining light in an eye causes it dilate…well thats abnormal. Use the swinging flashlight test to shine light in one eye, and bounce to the other eye. Do this again and again. If the affected pupil paradoxically dilates when light shines on it, (and other eye has no consensual constriction), this suggests a RAPD (See below). (more on this in a future blog post!)

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3. Pressure (IOP): Pressure should only be assessed when there is no suspicion of an open globe rupture. Normal range: 10-21 mmHg. Don’t squeeze the eyelids during the test, or you will get a false high reading.

• Goldmann applanation tonometry: The gold standard, on the slit lamp. Requires tetracaine numbing eye drops and fluorescein. 
• Electronic Tono-pens: Commonly found, even in the ED. Needs numbing drops.
• Rebound tonometer (e.g., iCare): Least invasive. No numbing drops needed! 

The Dilation Decision: The "Point of No Return"

You have now performed all the physical exams that must be conducted before administering dilating drops. Stop and think. Before dilating, run this safety checklist:

• Elevated Pressure (IOP) -> do not dilate until gonio exam completed (more on this in a future post)
• No PERRLA-DC -> no dilation until confirmed by the resident or staff
• Unless you are 100% certain, ask your resident or staff 

The Drops: Typically, you’ll administer a combination of Tropicamide (parasympatholytic) and Phenylephrine (sympathomimetic). Patients with darker irises have more pigment to "soak up" the medication and may require an extra round of drops compared to those with lighter eyes.

Slit Lamp 

Even if you aren't dilating, you can do most of this. If you are dilating, wait about 15–20 minutes for the drops to "cook" before trying to see the back. Move systematically from the front of the eye to the back:

• External: Check for symmetry, ptosis (drooping), proptosis (eyes bulging), inflammation/lacerations/skin lesions.
• Lids, Lashes, and Lacrimal Glands: Look at lash position. Evert the lids. Look for foreign bodies, inflammation, or blocked follicles.
• Conjunctiva and Sclera: Sclera should be white and non-icteric. Look for any injection (dilation and engorgement of blood vessels aka redness), chemosis (swelling), or lesions
• Cornea:  Check for clarity and abrasions. If abrasions are suspected (e.g., red eye in setting of trauma) apply fluorescein staining under blue light to see epithelial defects (e.g., HSV, foreign bodies).
• Anterior Chamber: Look for chamber depth and clarity. An unclear anterior chamber will have cell (white blood cells, looks like dust specks) and flare (protein leakage from inflammation, looks like smoke).

Simple Tips for Med Students to Get a Fist Bump: Comment on whether the chamber looks “shallow” or “deep”. If you see high pressures (IOP) and a shallow chamber, you’re looking at a major risk factor for Acute Angle Closure Glaucoma. Mentioning this will likely get you a fist bump.

• Iris: Iris should look flat, round pupil, no signs of vascularization (think diabetes), and no signs of transillumination (light beam through the pupil reflects off the retina and through the iris).
• Lens: Comment on lens clarity and whether phakic (own lens), pseudophakic (prosthetic lens), or aphakic (no lens).
• Vitreous: Similar cell and flare examination. Look for “tobacco dust” (pigmented cells), which can signal retinal tear, retinal detachment, or vitreous hemorrhage.

4. Fundus Exam: This is the hardest and most rewarding part. Don’t get frustrated, get in your reps! 

When examining the retina, comment on:

• Optic Disc: cup-to-disc ratio, margin clarity, pallor, thinning, elevation
• Macula: foveal light reflex, drusen, edema, exudates
• Vessels: nicking, tortuosity, hemorrhages
• Periphery: tears, holes, lesions, pigment changes

There are two main ways to conduct a fundus exams:

• Slit Lamp: Optic disc, macula, and vessels are best appreciated at the slit lamp with a  90D or 78D lens.
• Indirect Ophthalmoscope: That intense camping headlamp and a handheld 28D or 20D lens is best for examining the periphery (e.g., retinal tears). I find the indirect feels a bit more forgiving, so it might be easier to get some early fundus wins!

Putting It Together

A strong presentation shows you’ve synthesized the data from the history and the physical:

“This is a 28-year-old with a history of recurrent cold sores, presenting with 2 days of a painful, red right eye and significant photophobia. Vision is 20/40 in the right eye and 20/20 in the left. Pupils are equal, round, and reactive to light and accommodation both direct and consensual. Pressure is 15. On slit lamp, with fluorescein staining I appreciated a branching dendritic ulcer with terminal bulbs. I’m concerned about HSV and recommend starting acyclovir. I would not recommend topical steroids as this could worsen the infection”.

That’s a strong presentation. Even if the diagnosis ends up being ophthalmia nodosa from a seemingly friendly fuzzy caterpillar.

Common Pitfalls

• Skipping the backstory (the farmer, the caterpillars).
• Trying to be targeted before you know how to aim.
• Using vague language (“looks fine”).
• Not committing to a working diagnosis

Final Thought: A good exam isn't about seeing everything perfectly the first time. It’s about being reliable, systematic, and safe. Speed and efficiency comes later.

Next month:

Vision Loss on Your Ophthalmology Elective