Prompt access to cataract surgery is vital for preventing falls in older people

There is clearly an unmet need for timely, equitable access to cataract surgery in Australia

Vision problems and falls are common in older people, particularly those living in disadvantaged circumstances, and many people often experience both problems.1 In this issue of the MJA, Keay and colleagues2 report findings from the FOCUS study, which aimed to assess the impact of cataract surgery on the incidence of falls in older people. Their longitudinal study, which included a total of 409 participants, assessed the incidence of falls before and after first and second eye cataract surgery in people aged 65 years or more, a group at particular risk of falls. For the 118 people who underwent second eye surgery and participated in all follow‐ups, the authors found a large reduction in age‐ and sex‐adjusted fall incidence following second eye, but not first eye, cataract surgery.

Limitations of the study by Keay and colleagues2 include its observational design. Interpretations including a causal relationship between cataract surgery and falls should account for the fact that both falling and declining vision are each associated with ageing. Similarly, providing new or updated glasses is routine practice after cataract surgery, and may itself reduce fall risk. It was notable in this study that the proportion of participants with multi‐ or bifocal glasses, which are associated with greater fall risk,3 dropped from 40% of participants at the start of the study to 15% of those who had undergone second eye cataract surgery. Nonetheless, the findings of Keay and colleagues2 are consistent with those of previous studies, and provide further evidence for a causal component in the relationship between cataract surgery and reduced fall risk.

The best approach to exploring causation is a randomised control trial (RCT). RCTs undertaken in the United Kingdom found a reduction in fall incidence of about one‐third after first eye cataract surgery,4 but no effect of second eye surgery.5 The discrepancy between the findings of these trials and those of the FOCUS study requires further consideration.

The level of baseline vision impairment was more severe in the FOCUS study than in the two English RCTs: mean visual acuity before eye surgery in the UK first eye RCT was logMAR 0.304 (0 on the logMAR scale corresponds to 6/6 vision, 1.0 to 6/60), in the FOCUS sample it was 0.51 for the first operated eye and 0.40 for the second.2 Visual acuity after first eye cataract surgery in the UK trial was similar to that following second eye cataract surgery in the FOCUS study. This may explain the difference between the findings of the English and Australian studies. Consistent with this interpretation, improvement in stereopsis was greater following first4 than second eye surgery5 in the UK RCTs. It should be noted that visual acuity, contrast sensitivity, and stereopsis are often correlated, but only stereopsis requires good vision in both eyes.

However, the evidence is strong that second eye cataract surgery is beneficial in its own right,6 regardless of its effect on falls. Further, visual acuity alone should not be relied upon as the sole objective measure of visual function, as noted by NICE guidance;7 other parameters, such as contrast sensitivity and stereopsis, are also important.8 The NICE health economic model indicated that, even with logMAR 0.0 (6/6) vision, cataract surgery could be cost‐effective, without taking its impact on falls into account.7

The UK cataract surgery trials were ethically feasible only because they were undertaken when the waiting period in the National Health Service (NHS) was more than twelve months, and participants were randomised to expedited or routine care; as the prescribed maximum waiting time is now 18 weeks,9 such trials are unlikely to be repeated. In Australia, 70% of people undergoing cataract surgery do so as private patients.10 The FOCUS study participants, however, were public patients, who may be less advantaged than private sector patients. Indeed, the reported mean visual acuity (0.51 for the first operated eye) is generally considered to reflect later stage disease; in contrast, 36% of patients undergoing cataract surgery in the NHS during 2020–21 had visual acuity of 0.30 or better.11 Further, considerable time can elapse between referral and surgery in the Australian public hospital system, during which time falls are possible,12 though the situation is improving.10 Nonetheless, there is clearly an unmet need for timely, equitable access to cataract surgery in Australia.

The study by Keay and colleagues2 provides several important messages. The first is that public health authorities should ensure that the capacity for cataract surgery is adequate. The second is that physicians should consider screening for visual problems in patients who have had falls, if only with a simple enquiry about their eyesight. Finally, ophthalmologists should consider factors other than visual acuity when assessing patients for cataract surgery.