What instrument is used to determine a good fit of contacts?

The correct choice for determining a good fit of contact lenses is the slit lamp. This instrument provides a magnified, three-dimensional view of the anterior segment of the eye, including the cornea, conjunctiva, and the lens itself. By using a slit lamp, practitioners can assess the alignment of the contact lens on the cornea, evaluate the presence of any fitting issues such as excessive movement or tightness, and monitor the health of the cornea and surrounding tissues.

Additionally, the slit lamp allows the practitioner to observe how the lens interacts with the tear film, which is crucial for evaluating fitting characteristics and overall comfort for the patient. This comprehensive assessment is essential in ensuring that the lenses will perform well in practice and not cause any discomfort or complications.

While keratometers are used primarily to measure the curvature of the cornea, which is important for fitting lenses, they do not provide the detailed assessment of the fit and health of the eye that a slit lamp does. Lensometers are utilized to measure the power of the lenses and verify prescription accuracy, while pupilometers specifically measure the size of the pupils, which is less relevant to fitting contact lenses. Thus, using a slit lamp is key in ensuring a successful and healthy contact lens fit.