Which of the following conditions can be evaluated through cystoscopy?

Cystoscopy is a diagnostic procedure that allows for direct visualization of the interior of the bladder and urethra using a thin, flexible tube equipped with a camera. This examination is particularly useful for evaluating conditions related to the lower urinary tract.

Evaluating urethral strictures is well-suited for cystoscopy, as the procedure can directly visualize any narrowing or obstruction in the urethra. This can help in diagnosing the cause of urinary problems and determining the best course of treatment, which may include dilation or surgical intervention.

On the other hand, although bladder infections may be assessed indirectly through cystoscopy by looking for inflammation or other abnormalities, this procedure is not typically the first line of investigation for infections alone. Kidney stones more often necessitate imaging techniques like ultrasound or CT scans for diagnosis due to their location in the kidneys and ureters. Allergy-related symptoms are generally evaluated through different medical assessments such as skin tests or specific blood tests rather than cystoscopy, which is focused on structural examinations of the urinary tract.