A 51-year-old woman underwent uncomplicated cataract surgery OD with a toric IOL two weeks ago. She says her vision is clear but she feels dizzy and disoriented since the procedure. Uncorrected visual acuity is 20/20 OD, the IOL is well centered in the capsular bag, there is no posterior capsular opacity, and the macula is normal.
What questions would you ask this patient?
Her symptoms should be more precisely characterized. What does she mean by dizzy, is her environment spinning (vertigo) or does she feel light-headed (pre-syncope)? When do the symptoms occur? Are they associated with any particular tasks or activities? Does anything relieve or exacerbate the symptoms? Is the phenomenon binocular or monocular? Has she ever experienced this before? Does she have any other past ocular history? How is her general health? Have there been any changes in medication?
Additional information: she says the feeling is constant, worse with reading, only relieved by closing one eye, and similar to the double vision she had prior to strabismus surgery 15 years ago.
What tests would you perform?
The visual acuity (monocular and binocular, distance and near) and extraocular motility must be checked carefully with attention to diplopia and ocular misalignment on cover and alternate cover testing, respectively. She should have a manifest refraction and eye deviation should be measured.
The manifest refraction is plano + 0.25 x 135 OD and -1.50 sphere OS, with a +2.25 add OU, and the patient has a 3 prism diopter esophoria. How would you manage her?
The patient should be reassured that this is a small misalignment that may improve over time since she did not have the symptoms prior to cataract surgery. In the meantime, she should use her full glasses prescription and if her symptoms persist she can use a base out Fresnel prism or prism glasses to alleviate the diplopia.
Follow up: the patient noticed significant improvement with prism glasses. The esophoria gradually resolved over the next two and a half months and she was symptom free without prism.