While pseudophakic monovision — and the anisometropia and aniseikonia that come with it — may suggest an increased risk of falls for patients older than 65 years, a study published in the Canadian Journal of Ophthalmology is showing that those who undergo traditional intraocular lens implementation are actually the most likely group to experience a fall, even more than those who did not undergo cataract surgery at all.
A reduction of stereoacuity can increase the risk of falls, according to the report. Although monovision patients do experience stereoacuity loss, these patients do not appear to experience elevated fall risk, according to the report. The research team speculate that this is because ocular dominance and a potential pseudoaccommodation from improved visual acuity at both near and distance may mitigate fall risk, despite the reduced stereoacuity. However, the study shows pseudophakic single-vision patients may carry a higher risk of fall, a higher mean number of falls after cataract diagnosis, and a faster time to fall than both those with monovision and patients who did not undergo any cataract surgery.
Researchers retrospectively reviewed the records of patients with bilateral cataracts who had been diagnosed at age 60 years or older. They excluded patients with unilateral cataract diagnosis or surgery and patients who had fallen before cataract diagnosis.
They included 241 patients with pseudophakic monovision (66.4% women), 2809 patients with pseudophakic single vision (57.6% women), and 10,335 patients who had not undergone surgery (53.1% women) in the study (P <.001). The median follow-up period was 2.9 years from cataract diagnosis.
Patients with pseudophakic single-vision were significantly older when they received their cataract diagnosis (72.7±7.4 years) than those with pseudophakic monovision (69.3±6.2 years) and those who had not undergone surgery (69.4±6.9 years, P <.001). Patients with pseudophakic monovision (22%) were significantly more likely to have a pre-existing diagnosis of myopia (8.3%) compared with those with pseudophakic single-vision or had not undergone surgery (8.4% P <.001).
The researchers discovered that 850 patients (14 pseudophakic monovision [5.8%], 222 pseudophakic single-vision [7.9%], 614 no surgery [5.9%]) had a documented fall after their cataract diagnosis. Frequency of falls was significantly higher among patients with pseudophakic single-vision compared with those who had not undergone surgery (P <.001).
Post-diagnosis, patients with pseudophakic single-vision had a significantly higher mean number of falls compared with patients without surgery (0.11 vs 0.082 P =.003).
“Contrary to our initial hypothesis, we found no impact of pseudophakic monovision on fall risk in our cohort,” the researchers report.
After cataract surgery, 175 (9 pseudophakic monovision, 166 pseudophakic single-vision) patients had a documented fall. The mean number of falls was not significantly different between patients with pseudophakic monovision and patients with pseudophakic single-vision.
When the researchers controlled for age, sex, and preexisting myopia, they found increased age at time of cataract surgery significantly increased fall risk after surgery (HR=1.05 P <.001).
Patients who had not undergone surgery were significantly more likely to fall if they had a pre-existing diagnosis of myopia (HR=1.31 P =.046) or if they were women (HR=1.29 P =.002). Patients who were older at the time of cataract diagnosis were more likely to fall (HR=1.05 P <.001).
“These findings suggest that perhaps the residual accommodation in cataract patients who have not undergone surgery may potentially protect against falls, because the ability to focus, although greatly diminished, is still retained in phakic cataract patients but not in pseudophakia,” according to the researchers.
Limitations of the study included a lack of randomization, inability to assess visual acuity or postoperative use of corrective glasses, and size of the pseudophakic monovision cohort.
Rosenblatt TR, Vail D, Ludwig CA, et al. Fall risk in patients with pseudophakic monovision. Can J Ophthalmol. Published online August 19, 2021. doi:10.1016/j.jcjo.2021.07.010