**Question:** Which diagnostic procedure is not done in a dilated pupil?

**Core Concept:** Diagnostic procedures in ophthalmology often require pupillary dilation for proper visualization of the fundus and other ocular structures. Pupillary dilation restricts the size of the pupil, enabling the examination of the retina and optic nerve.

**Why the Correct Answer is Right:** A dilated pupil makes it easier to visualize the fundus, allowing the clinician to assess the health of the retina, optic disc, macula, and the presence of any abnormalities. In contrast, the procedure that is not done in a dilated pupil is Fundus Photography.

**Why Each Wrong Option is Incorrect:**

A. **Optical Coherence Tomography (OCT):** OCT is a non-invasive imaging technique used to visualize the retinal layers and optic nerve head. It does not require pupillary dilation and can be performed with a mydriatic drop washout period, allowing pupils to return to their normal size.

B. **Fundus Fluorescein Angiography (FFA):** FFA is a diagnostic test that helps visualize blood flow in the retina and choroid. It requires a dilated pupil for optimal visualization and is performed after the mydriatic drop washout period.

C. **Gonioscopy:** Gonioscopy is used to visualize the angle between the cornea and the sclera, which is essential for diagnosing glaucoma and assessing intraocular pressure. A dilated pupil is necessary for proper visualization of the angle and surrounding structures.

D. **Slit-lamp examination:** Slit-lamp examination is a routine ophthalmic examination used to assess the anterior segment of the eye (cornea, iris, lens, and anterior chamber). A dilated pupil allows for a better visualization of these structures, making the correct answer correct.

**Clinical Pearl:**

A dilated pupil is essential in many ophthalmic examinations to ensure proper visualization and accurate diagnosis. In certain cases, mydriatic drops may be used to temporarily constrict the pupil and improve visualization during certain procedures, but the effect of these drops wears off after a certain period, allowing pupils to return to their normal size.