Bloodshot Eyes

What Causes Red Eyes?

Red eyes can have various causes, ranging in severity from 'worrying' to 'needs attention'.  Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

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  • check your overall health status
  • understand what's happening to your body
  • let The Analyst™ find what's wrong

Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms.  In order to diagnose red eyes, we could:

  • Research the topic
  • Find a doctor with the time
  • Use a diagnostic computer system.
The process is the same, whichever method is used.

Step 1: List all Possible Causes

We begin by identifying the disease conditions which have "red eyes" as a symptom.  Here are four possibilities:
  • Dry Eye
  • Iritis
  • Conjunctivitis
  • Sarcoidosis

Step 2: Build a Symptom Checklist

We then identify all possible symptoms and risk factors of each possible cause, and check the ones that apply:
frequent swollen axillary nodes
occasional red eyelids
multiple painful inguinal nodes
frequent swollen cervical nodes
frequent itchy eyes
eyelid twitch
severe vision disturbances
multiple painful cervical nodes
constant thirst
moderate eye discharge
... and more than 20 others

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of red eyes:
Cause Probability Status
Iritis 99% Confirm
Conjunctivitis 14% Unlikely
Sarcoidosis 0% Ruled out
Dry Eye 0% Ruled out
* This is a simple example to illustrate the process

Arriving at a Correct Diagnosis

The Analyst™ is our online diagnosis tool that learns all about you through a straightforward process of multi-level questioning, providing diagnosis at the end.

If you indicate eye problems, The Analyst™ will ask further questions including this one:
Are the whites of one or both of your eyes bloodshot (with red/pink veins showing)? Only answer if you have had bloodshot eye(s) for more than 2 days, and it is not from rubbing them.
Possible responses:
→ No / for under 2 days / from rubbing / don't know
→ Significant episodes in the past
→ A little - they appear slightly red colored
→ Significantly - numerous individual red veins
→ Seriously - there is a large, very red area
Based on your response to this question, which may indicate past episodes of bloodshot eyes, bloodshot eyes or very bloodshot eyes, The Analyst™ will consider possibilities such as:
Dry Eye

Dry eye may cause your eyes to always look red.

Concerned or curious about your health?  Try The Analyst™
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