Magnification in Indirect ophthalmoscopy –a) Depends on power of lens usedb) Depends on refractive error of patientc) Independent of refractive error of patientd) independent of power of lens used

**Core Concept**
Indirect ophthalmoscopy is a diagnostic technique used to visualize the retina and posterior segment of the eye. The magnification in indirect ophthalmoscopy is a critical factor in assessing retinal lesions and abnormalities. The underlying principle being tested is how the magnification is affected by the power of the lens used and the refractive error of the patient.

**Why the Correct Answer is Right**
The magnification in indirect ophthalmoscopy is determined by the power of the lens used. The higher the power of the lens, the greater the magnification of the image formed on the retina. This is because the power of the lens determines the focal length of the image, and a higher power lens results in a shorter focal length, which increases the magnification. The refractive error of the patient does not affect the magnification in indirect ophthalmoscopy because the image is formed on the retina, not on the patient's cornea.

**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because while the power of the lens does affect the magnification, it is not the only factor. The refractive error of the patient also plays a role in determining the final image size.
* **Option B:** Incorrect because the refractive error of the patient does not affect the magnification in indirect ophthalmoscopy. The image is formed on the retina, not on the patient's cornea.
* **Option D:** Incorrect because the power of the lens does affect the magnification, and it is not independent of the power of the lens.

**Clinical Pearl / High-Yield Fact**
In indirect ophthalmoscopy, the power of the lens used is crucial in determining the magnification of the image. A higher power lens is often used to visualize smaller retinal lesions, while a lower power lens is used to visualize larger lesions.

**Correct Answer:** D. independent of power of lens used