Which instrument is typically used as an eye speculum during an iridectomy?

The Barraquer eye speculum is specifically designed for use in ophthalmic surgeries, including procedures like iridectomy. It features a lightweight design and a unique shape that allows for optimal exposure of the eye while minimizing trauma to the surrounding tissues. The adjustable nature of the Barraquer speculum ensures that the surgeon can maintain adequate exposure throughout the procedure, which is crucial for precise and effective intervention in the delicate structures of the eye.

In contrast, instruments like the Castroviejo are primarily used for suturing and may not provide the necessary exposure required during procedures such as iridectomy. The Wescott scissors are surgical scissors designed for dissecting tissues but do not serve as a means to hold the eyelids open. The McPherson forceps are used for grasping and handling tissues, which does not apply to the role of an eye speculum. Thus, the unique characteristics of the Barraquer make it the appropriate choice for this specific function in surgery.