Top 3 lists to take the detective work out of differential diagnoses

November 15, 2018
Shelby May

Shelby is a third-year student at Southern College of Optometry. She is particularly interested in Vision Therapy and Pediatrics. Any hours not spent studying or writing are enjoyed playing board games, giggling at cat memes, and baking.

The views expressed here belong to the author. They do not necessarily represent the views of Optometry Times or UBM.

Creating “Top 3” lists for differential diagnoses can limit the ocean of diagnoses into the three most common types, as well as give identifying features to each.

This is more concise and less complex than most of the flow charts I have seen. Here, I am sharing the lists I keep in my little clinic notebook.

You will notice repeat differentials as well as obvious choices that no self-respecting OD would be able to forget, much less need a cheat sheet for. But don't fret, the idea here is not to be insulting- it's to remind yourself of Occam’s razor.

Top 3 clinical differentials

Red eye
• Allergic conjunctivitis: Affected by seasons, papillae
• Bacterial conjunctivitis: Yellow discharge, young patients
• Viral conjunctivitis: Watery discharge; one eye, then other

Distance blur
• Myopia: Constant, young
• Dry eye: Fluctuates between blinks
• Diabetes: Fluctuates over days, uncontrolled blood sugar

Near blur (young patients)
•Hyperopia (latent): Trouble reading, dim initial reflex
•Accommodative insufficiency: Tries quickly at near, frontal headaches
•Binocular issue: double vision at near, avoids reading

Related: How to avoid misdiagnosing common and common conditions as a student

Near blur (adult patients)
•Presbyopia: Slow onset, at or past 40 years old
•Cataract: Reading is poor, increased lighting helps, halos around lights at night
•Diabetes: Fluctuates over days, uncontrolled blood sugar

Foreign body sensation
•Dry eye: No foreign object found, tearing, meibomian gland dysfunction (MGB) findings
•Foreign body: An actual foreign body; vertical corneal tracking if embedded
•Abrasion

Dry eye
•Evaporative dry eye: Capped glands, turbidity, gland loss on lid transillumination
•Aqueous deficient dry eye: Small tear prism, elderly patient (involtional stenosis)
•Environmental dry eye: Incomplete lid closure in blink, patient runs fan/AC overnight

Diplopia
•Binocular disorder: Young or college-aged patient, no precipitating event
•Traumatic brain injury (TBI): Sudden onset, precipitating event
•Diabetes: Palsy signs, uncontrolled blood glucose

Pigment on retina
• Nevus: Red-free filter makes it disappear
•Congenital hypertrophy of the retinal pigment epithelium (CHRPE): Flat, pigment is in periphery
•Macular mottling: Older, Caucasian patient; history of macular degeneration

Blood in retina (some)
•Diabetic retinopathy: Dot-blot hemes, mid-peripheral, history of poor control
•Hypertensive retinopathy: Flame-shaped hemes, engorged veins, tortuosity
•Glaucoma: Drance heme (nearly pathognomonic)

Blood in retina (lots)
•Preretinal hemorrhage: Recent Valsalva maneuver or trauma; boat-shaped
•Cential retinal vein occlusion (CRVO): History of hypertension or diabetes; blood in all four quadrants
•Vitreous hemorrhage: History of diabetes, neovasuclarziation; “foggy” views

Your list will vary
It is likely that your personal “Top 3s” will be heavily influenced by your location.

For example, when I first started practicing in a clinic I lived in Memphis, an area that has a high prevalence of diabetes and hypertension. Both show up on my lists frequently because those conditions are what what I saw most commonly.

Now that I am externing in a private practice that handles a lot of vision therapy, my “Top 3s” have shifted toward more functional diagnoses.

Feel free to adjust yours as needed! There are no rights or wrongs!

Related: 3 tips to improve doctor-dispensing as a student

Missing information?
I know some out there who will argue that there are important diagnoses missing in the list I provided. While I completely understand that plight, this is the whole reason I made the lists. There are dozens upon dozens of diagnoses, details, and exceptions. That is what makes optometry hard but also challenging and rewarding.

Resist your inner completionist and accept this exercise in simplicity and probability. If you feel a desire to add more details or point out exceptions, you are missing the point. You will end up rewriting the Wills Eye Manual instead of a refreshing reference. Spare yourself that hand cramp.

Applicable elsewhere
These simplifiers have started to creep into other aspects of my life as well. I now have a few on adjusting glasses, indecisive dinner plans sorted by main ingredient, and even one on great fallback date nights.

I love how they fit nicely on any Post-It note for sticking wherever. (If it doesn't fit on a Post-It, you have too much detail.)

Read more by Shelby May

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