Introduction
This presentation will examine the most common clinically encountered cataract types.

However, before we commence, let's take a bit of time to discuss how to best evaluate a patient's lens for opacities. First, evaluation through a dilated pupil is best. Once the patient is dilated, several techniques can be used to examine the lens:

• Direct ophthalmoscopy
  
  With the ophthalmoscope approximately 6 to 8 inches from the patient's eye and 3 to 4 diopters of plus power dialed in, use retro-illumination to detect any opacities (this procedure is known as distal ophthalmoscopy).
  
  
• Slit lamp examination
  
  For the initial evaluation, use a parallelepiped beam positioned at a 45-60° angle. Perform a thorough scan of the front and back half of the lens. To localize opacities within the lens, use an optic section with the beam at a 45-60° angle. One can also use retro-illumination to detect lens opacities with the slit lamp.