Differential Diagnosis for Iris Anomaly
The patient presents with a perceived missing piece of the iris in the right eye, without any accompanying pain or vision changes, and with pupils that are equal, round, and reactive to light and accommodation (PERRLA). Given these symptoms, the following differential diagnoses are considered:
Single most likely diagnosis
- Coloboma of the Iris: A congenital condition where there is a defect in the iris, often appearing as a missing piece. It can be isolated or part of a broader syndrome. The absence of pain or vision changes and the PERRLA finding support this diagnosis, as colobomas are usually asymptomatic and do not affect pupil reactivity.
Other Likely diagnoses
- Iris Tear or Defect: Traumatic or surgical incidents can cause tears or defects in the iris, which might appear as a missing piece. The lack of reported trauma or surgery makes this less likely but still a consideration.
- Iridocorneal Endothelial Syndrome (ICE): A rare condition characterized by an abnormal iris, but it often presents with other symptoms like glaucoma or corneal edema, which are not mentioned here.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Malignant Melanoma of the Iris: Although rare, iris melanomas can present with a variety of symptoms, including a perceived defect in the iris. Given the potential severity of this condition, it must be considered and ruled out with appropriate imaging and examination.
- Intraocular Tumor (e.g., Medulloepithelioma): Tumors within the eye can cause irregularities in the iris. These are rare but critical to diagnose early due to their potential impact on vision and life.
Rare diagnoses
- Axenfeld-Rieger Syndrome: A genetic disorder that affects the development of the anterior segment of the eye, including the iris, and can present with iris defects. It is associated with other systemic anomalies.
- Peter's Anomaly: A congenital condition affecting the cornea and iris, often associated with other ocular and systemic abnormalities. The presentation typically includes corneal opacity and iris defects.