Before the pupils are dilated for an ophthalmoscopic examination, increased intraocular pressure and a shallow anterior chamber must be ruled out. Small cataracts stand out as dark defects in the red reflex. A large cataract may obliterate the red reflex. Slit-lamp examination provides more details about the character, location, and extent of the opacity. Treatment Frequent refractions and eyeglass prescription changes help maintain useful vision during cataract development.
Many ophthalmologists recommend that UV-coated glasses or sunglasses be worn while in the sunlight.
Disabling glare can also be an indication for surgery and is most common with posterior subcapsular cataracts. Cataract extraction is usually performed using local anesthesia and IV sedation. The smallest incision is used with phacoemulsification, thus enabling the fastest healing. A plastic or silicone lens is almost always implanted intraocularly to replace the optical focusing power lost by removal of the crystalline lens. Iris plane intraocular lenses are now rarely used in the USA because many designs were associated with a high frequency of postoperative complications.