A thorough discussion of diplopia is presented in BCSC Section 6, Pediatric Ophthalmology and Strabismus, and in Section 5, Neuro-Ophthalmology. There are 2 types of diplopia, monocular and binocular, which can be easily differentiated by covering the eyes. If the diplopia is present only with both eyes open, then it is binocular. If it is still present with only 1 eye open, then it is monocular. As it pertains to cataract surgery, monocular diplopia generally results from optical aberrations in the operative eye. Binocular diplopia results from ocular misalignment or anisometropia (Table 11-3). It is important to document preoperative ocular misalignment, which is present in 13%–16% of patients undergoing cataract surgery. Regarding intractable binocular diplopia, a 2008 study of patients found that the most common cause was extraocular muscle restriction or paresis in the anesthetic block group and decompensation of a preexisting phoria in the topical group.
Corneal topography may be useful in determining a corneal cause of diplopia. OCT may help exclude macular causes of monocular diplopia. Treatment of monocular diplopia is directed at the source, as is treatment of persistent binocular diplopia. Disruption of fusion and anisometropia may be managed by proper optical correction with a prism and slab-off bifocal if necessary. Cataract surgery on the contralateral eye or contact lens correction may be required. If a muscle paresis/restriction is present, prism correction often is adequate; however, referral to a specialist in strabismus may be necessary.
Table 11-3 Causes of Postoperative Diplopia
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.