Monocular Diplopia or Polyopia
Occasionally in cataractous eyes, nuclear changes are localized to the inner layers of the lens nucleus, resulting in multiple refractile areas at the center of the lens. Such areas may best be seen as irregularities in the red reflex on retinoscopy or direct ophthalmoscopy. This type of cataract can result in monocular diplopia or polyopia, including ghost images and occasionally a true second image. Use of a pinhole occluder can eliminate the symptoms and be helpful in evaluation (for more on the pinhole test, see the section Potential Acuity Estimation later in this chapter). Monocular diplopia can also occur with abnormalities of the cornea and retina or other disorders of the eye (see BCSC Section 5, Neuro-Ophthalmology).
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.