Corneal diseases are a huge part of ophthalmology, and they can range from a minor annoyance to a sight-threatening emergency. Since you're looking into keratitis, ulcers, and transplants, let's break these down into high-yield chunks.

1. Keratitis & Corneal Ulcers

Keratitis is essentially inflammation of the cornea, and when that inflammation leads to a breach in the corneal epithelium with underlying stromal involvement, we call it a corneal ulcer.

• Bacterial Keratitis: Often seen in contact lens wearers (think Pseudomonas). Look for a "hypopyon" (pus in the anterior chamber).
• Viral Keratitis: Herpes Simplex Virus (HSV) is the classic exam favorite. It presents with a characteristic dendritic ulcer (linear, branching with terminal bulbs) that stains with fluorescein.
• Fungal Keratitis: Usually follows trauma with vegetative matter (like a branch hitting the eye). Look for feathery margins and satellite lesions.
• Acanthamoeba: Associated with poor contact lens hygiene (using tap water). The pain is often way out of proportion to the clinical findings, and you might see a ring infiltrate.

2. Corneal Transplant (Keratoplasty) Indications

When the cornea becomes too scarred, distorted, or opaque to function, we look at a transplant. We generally categorize the reasons into four main groups:

• Optical: To improve vision (e.g., Keratoconus, Bullous keratopathy, corneal dystrophies).
• Tectonic/Structural: To restore the integrity of a thinned or perforated cornea.
• Therapeutic: To remove active disease that isn't responding to meds (like a stubborn fungal ulcer).
• Cosmetic: To improve the appearance of a disfigured eye (usually without sight potential).

I'll pull up some detailed lessons on these topics so you can dive into the specifics of management and clinical features.

It's also really helpful to see the differences between these types of keratitis side-by-side, as they often show up as "spotters" or clinical vignettes in exams.

I've put together a comparison table for you to help distinguish the most common types of infectious keratitis.

To wrap this up, let's look at some practice questions to see how these concepts are tested. I'll pull up a quiz that covers corneal ulcers and transplantation.

That covers the essentials of corneal diseases and when a transplant becomes necessary! Remember, the key to these questions is often the history (contact lenses vs. vegetative trauma) and the staining pattern (dendritic vs. feathery).

If you want to see an image of a dendritic ulcer or a hypopyon, just let me know!