Purpose: To determine whether higher-order aberrations can explain the monocular diplopia reported by a patient.
Design: Observational case report.
Methods: A patient complaining of monocular diplopia was examined with the Hartmann-Shack aberrometer to determine if the higher-order wavefront aberrations could account for the diplopia. The patient had a mild cortical cataract, and measurements were made before and after lensectomy. In addition, the retinal image was simulated using Zernike polynomials.
Results: Spherical aberration (0.20 microm for 4-mm pupil) and secondary astigmatism (-0.12 microm) were increased in the eye. The simulated retinal image had a double configuration that was approximately the same as the subjective image reported by the patient. After cataract surgery, the diplopia disappeared, and the spherical aberrations and secondary astigmatism were considerably decreased.
Conclusions: The monocular diplopia probably stemmed from the combined effects of spherical aberration and secondary astigmatism caused by the cortical cataract.