Eye Anatomy and Key Diagnoses Rule of 2s
The rule of 2s, as illustrated below, is a simple method with an anatomical approach to the major ocular diagnoses and is meant to provide a general framework to guide the physical exam and include or eliminate certain conditions. The rule of 2s is easy to remember as it contains the number 2 in the context of eyes and proceeds from layer to layer of the eye in an anterior to posterior direction highlighting the 2 major associated diagnoses of that layer.
There is significant overlap among conditions that cause a red, painful or red and painful eye. Here are additional cards that may help in your evaluation:
Anterior Eye – Utilize slit lamp exam
Posterior Eye – Use fundoscopy and ultrasound
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