Helping patients to sleep easy

Poor sleep is common in cataract patients. While surgery helps, intraocular lens (IOL) choice does not appear to affect sleep quality improvement, according to Gokulan Ratnarajan MD, Oxford Eye Hospital, UK. Dr Ratnarajan explained the findings of a major UK study, which examined the impact of two different types of IOLs on sleep quality pre- and post-cataract surgery. He said that, as cataracts make the crystalline lens cloudy, they can reduce the amount of light that reaches the 
retina, which may cause an abnormal circadian rhythm that affects sleep. The dual centre prospective study compared patients at Oxford Eye Hospital who received an ultraviolet blocking IOL and patients at Prince Charles Eye Unit, UK, who received a blue-filtering IOL, using the Pittsburgh Sleep Quality Index (PSQI) at one month preoperatively, one month postoperatively, and 12 months postoperatively. “With our sample of over 1,000 patients the results showed that half our patients undergoing cataract surgery were poor sleepers,” Dr Ratnarajan said. PSQI IMPROVEMENT Postoperatively, the PSQI improvement at one month was 0.40 in the study patients and this reached statistical significance, he reported. However, at 12 months, while there was still an improvement in sleep compared to preoperative levels (0.30), it did not reach statistical significance. The primary endpoint was the difference, if any, between the lenses with regards to sleep quality. In fact, the sleep improvement trend was mirrored in both patient groups. So although there was a statistically significant improvement at one month and improvement at 12 months, it was not statistically significant, he reported. Other key findings included that sleep quality and sleep latency, i.e. the time it takes to fall asleep, were the greatest improvement noted in the patients, added Dr Ratnarajan. The study also found that patients with poor visual acuity were 1.62 times as likely to have poor sleep. Female patients (1.32 times versus males) and elderly patients were also more likely to be poorer sleepers. “So in summary, poor sleep is common in our patients undergoing cataract surgery and this is worth considering. Subjective quality of sleep postoperatively is independent of IOL choice, and both groups had a statistically significant improvement at one month, but this was not maintained at 12 months," said Dr Ratnarajan. Overall, the study showed that cataract surgery not only improves patients’ vision and quality of life, but also their sleep, he reiterated. Gokulan Ratnarajan: g.ratnarajan@gmail.com