Intraocular lens exchange to restore habitual myopic refraction may alleviate persistent dizziness and visual discomfort following cataract surgery in patients with strong visual dependence.
The case involved a 79-year-old woman with mild preoperative myopia of approximately −2.0 D and no history of spectacle use. Five months prior to presentation, she underwent bilateral cataract surgery with monofocal intraocular lenses (IOLs) targeted for distance vision. Although uncorrected distance visual acuity reached 1.2 in both eyes following surgery, she reported persistent blurred vision, dizziness, and a floating sensation that interfered with walking outdoors, reading, and using stairs. Ophthalmic examination revealed no abnormalities to explain her symptoms, and brain magnetic resonance imaging and neurologic evaluation were unremarkable.
Investigators evaluated whether vestibular dysfunction with strong visual dependence could explain the symptoms and whether recreating the patient’s habitual refractive state would relieve them. Stabilometry showed abnormal postural sway, particularly under rubber-load conditions. Additional vestibular testing showed reduced left-sided vestibular-evoked myogenic potentials and decreased function of the left anterior semicircular canal on video head impulse testing. Together, these findings supported a diagnosis of left-sided vestibular dysfunction with strong visual dependence.
Investigators hypothesized that the abrupt shift from longstanding myopia to near emmetropia had disrupted visual-vestibular compensation. A diagnostic trial of +3.5 D daily disposable contact lenses in both eyes was used to approximate the patient’s habitual −2.0 D refractive state. Within 1 week, she reported marked improvement, including greater stability while walking and the ability to read without dizziness.
Following the successful refractive trial, treatment options included continued contact lens use, laser-assisted in situ keratomileusis, an add-on IOL, and IOL exchange. The patient elected IOL exchange, which was performed bilaterally 5 months following the initial cataract surgery. The replacement lenses targeted an approximately −2.61 D spherical equivalent in the right eye and −2.05 D in the left eye. Following exchange, corrected distance visual acuity was 1.2 in both eyes, with refraction of −2.0 sphere with −1.0 cylinder in the right eye and −1.75 sphere with −0.75 cylinder in the left. The patient reported immediate relief from the floating sensation and blurred vision and resumed daily activities without corrective lenses.
Objective balance measures also improved. At 10 months following IOL exchange, locus length per unit area with the eyes open decreased from 49.46 to 32.10, the area Romberg ratio decreased from 2.52 to 1.20, and the velocity Romberg ratio under rubber-load conditions decreased from 3.11 to 1.65. Neural network analysis showed a decrease in the probability of abnormality from 100% to 22%, and vestibular-evoked myogenic potential findings improved. The patient maintained stable vision without symptom recurrence through 26 months of follow-up.
The report was limited to 1 patient, preventing a definitive causal relationship from being established between the refractive change and vestibular symptoms. The investigators also noted the limited generalizability of the stabilometry findings and a lack of outcomes beyond 26 months. Larger studies are needed to determine whether restoring habitual refractive status through IOL exchange is effective in a broader population of patients with visually dependent vestibular dysfunction.
The case suggests that vestibular dysfunction with strong visual dependence may warrant consideration in patients with persistent dizziness or visual discomfort following otherwise successful cataract surgery when ophthalmic abnormalities do not explain the symptoms. Restoring the patient’s habitual refractive state was associated with symptom relief and improved objective balance measures, although treatment efficacy cannot be established from a single case. “In visually dependent patients, substantial changes in habitual refractive state may exacerbate vestibular symptoms,” wrote lead study author Kaori Morii, MD, of Morii Eye Clinic and the Department of Ophthalmology at Asagiri Hospital, and colleague.
The authors reported no conflicts of interest.
