Crohn’s disease is a type of inflammatory bowel disease (IBD) that involves chronic inflammation of the gastrointestinal tract. Crohn’s disease can affect any part of the gastrointestinal (GI) tract, from the mouth to the anus. It is different from ulcerative colitis, another type of IBD, that only affects the colon (large intestine).
It’s not entirely clear why Crohn’s disease affects the eyes in some people. Crohn’s is an inflammatory disease, and inflammatory conditions often affect multiple parts of the body. The medications used to treat Crohn’s disease can also contribute to eye problems. For example, long-term corticosteroid use can lead to glaucoma or cataracts.
What Are Symptoms of Crohn’s Disease?
Symptoms of Crohn’s disease can develop slowly and progressively worsen:
- Frequent bowel movements
- Diarrhea
- Abdominal pain and cramping
- Nausea
- Vomiting
- Loss of appetite
- Fatigue
- Fever
- Weight loss
- Gastrointestinal ulcers
- Rectal bleeding/blood in stool
- Disease around the anus
- Shortness of breath due to anemia
- Skin lesions and joint pain and swelling (most commonly seen in Crohn's granulomatous colitis)
- Inflammatory abscesses of fistulas (in severe cases)
What Eye Problems Are Related to Crohn’s?
About 10% of people with an inflammatory bowel disease such as Crohn’s experience eye problems such as:
- Uveitis
- Inflammation of the uvea (middle layer of the eye wall)
- Symptoms include pain, blurred vision, sensitivity to light, and eye redness
- Keratopathy
- An abnormality of the cornea
- Episcleritis
- Inflammation of the outer coating of the white of the eye (the episcleral)
- Symptoms include eye redness, pain, and tenderness
- Dry eyes
- Caused by decreased tear production or increased tear film evaporation
- Symptoms include eye infection and irritation such as itching and burning
How Are Eye Problems Caused by Crohn’s Disease Diagnosed?
In patients who have Crohn’s disease, eye problems are diagnosed with an eye exam and use of a “slit lamp” that allows the doctor to look at the inside of the eye.
What Is the Treatment for Eye Problems Due to Crohn’s Disease?
Treatment for Crohn’s disease involves a combination of medications, diet changes, and sometimes surgery. When Crohn’s disease is controlled, eye problems usually improve.
Medications used to treat Crohn’s disease include:
- Aminosalicylates (5-ASA)
- Azathioprine
- Corticosteroids
- Antibiotics
- Sulfasalazine
Biologics/biosimilar therapies
Immunomodulators
Diet changes used to treat Crohn’s disease include:
- Eating a healthy, balanced diet that includes:
- Eating 4-6 small meals daily
- Restricting dairy intake in patients who are lactose-intolerant
- During flares:
- Consuming soft, bland foods
- Avoiding spicy or high-fiber foods
Surgery used to treat Crohn’s disease includes:
- Strictureplasty: to repair a narrowing (stricture)
- Bowel resection: to remove a damaged portion of the small or large intestine
- Fistula removal
- Abscess drainage
- Colectomy: removal of the colon
- Proctocolectomy: removal of the colon and rectum
Specific treatment for eye problems caused by Crohn’s disease include:
- Uveitis: eye drops containing steroids to help reduce inflammation
- Keratopathy: usually it does not require treatment
- Episcleritis: steroid eye drops and topical vasoconstrictors
- Dry eyes: artificial tears, Vitamin A supplements (orally or by intramuscular injection), and antibiotics for severe infection
From 
https://www.crohnscolitisfoundation.org/
https://blog.mercy.com/crohns-disease-early-signs-prevention/