When evaluating a 90D (Diopter) lens, which is the gold standard for general fundus examination, you must prioritize optical clarity and coating quality. Ensure the lens is made of high-transmission glass to provide a high-resolution retinal image. The static field of view should typically be around 74° to 89°, with a magnification factor of approximately 0.76x. Additionally, verify that the lens features a high-quality anti-reflective (AR) coating to minimize glare and reflections during slit lamp examinations.