Eye conditions you should be familiar with as they may lead to a systemic disorder being diagnosed:

Thyroid eye ds: Hyperthyroidism is a disorder that many of us pick up seeing a person walking by with huge popping out eyes.

Early signs seen in hyperthyroidism include eyelid edema, lid retraction, inability to completely converge (one of the earliest eye signs besides lid edema) and exophthalmos. Although there are many other signs, and I remember making a list of about 40 signs in medical school.

Hyperlipidemia presents with Xanthelasma:

Nephrotic syndrome related orbital edema: Anasarca or generalized edema presents in nephrotic syndrome and other causes of hypoproteinemia like protein malnutrition (Kwashiorkor). Hemodynamic forces favor the leakage of fluid into interstitial tissue and creating edema. unlike pressure driven edema (like CHF) it is not dependent in location.

Ptosis: Horner's syndrome. I have had the skill or opportunity of diagnosing it by myself only once in real life but so many times in a test. It is due to the severance of the sympathetic supply of the upper eyelid. This also leads to miosis, anhydrosis and lack of cilio-spinal reflex (dilatation of pupil on rubbing the nape of the neck in a normal person). Please remember that Facial nerve palsy or Bells palsy does not cause ptosis. It causes inability to close the eyelid. Horner's is seen in pancoast's tumor (apical lung cancer)

Scleritis: Seen in connective tissue disorders like SLE, RA, Ankylosing spondylitis, crohn's disease and other seronegative arthritides.

Uveitis is inflammation of the Iris and its adjacent system. It may be diagnosed by looking at an eye and inspecting the anterior chamber of the eye. There is an inflammatory response that collects in the anterior chamber and looks like a hazy level there.

Note in the red eye, on the lateral margin, there is a clear area just lateral to the cornea - the limbic clearing. Patient had pain in affected eye when light was shone on unaffected eye.

Oculocardiac reflex in case with orbital fracture: It is a dangerous reflex that slows the heart down and can even stop it. It occurs due to increased pressure in the orbit. The increased pressure is transmitted to the brain via trigeminal nerve and the heart slows down due to the vagus nerve.