Advantages of ISBCS

Charles Claoué MD

The advantages of immediately sequential bilateral cataract surgery (ISBCS) so outweigh the risks that consideration should be given to widespread adoption of the practice, Charles Claoué MD told delegates attending the 2015 Congress of the European Society of Ophthalmology (SOE) in Vienna, Austria.

Discussing the current risk of functional or bilateral blindness from endophthalmitis stemming from ISBCS, Prof Claoué, of Queen’s Hospital, London, UK, said that it was important to base one’s judgment on statistical evidence rather than gut feeling or a vague sense that ISBCS might be riskier to the patient.

“The reality is that when we examine the risk of being functionally blind from simultaneous bilateral endophthalmitis after ISBCS, it is lower by more than a factor of 10 than the risk of being struck by lightning and much lower than the risk from death from a general anaesthetic,” he said.

Prof Claoué said that it was important to define risk and the role it plays in our lives. “Often we want to stick our head in the sand and pretend that risk is not there. Or at the other end of the scale we can think we are somehow immune to risk and will always emerge unscathed. But there is an unpredictability to risk that we often choose to ignore,” he said.

Risk is defined as the probability of an adverse effect from a defined activity, or the probability of losing something of value, said Prof Claoué. “Throughout life, we choose or avoid risk. Some of us choose to smoke, to drive fast cars, to practise unsafe sex, to travel by plane, car or motorbike, to undergo surgery, and so on,” he said.

The risk of endophthalmitis in routine unilateral cataract surgery is about 0.029 per cent, based on data from the Swedish cataract registry, said Prof Claoué.

“If you take this figure and calculate the risk of bilateral simultaneous endophthalmitis after ISBCS, the figure is 0.00000841 per cent, which is about one case in 11.9 million, assuming it is a random event,” he added.

LINKAGE FACTOR

A common objection to this statistic is the so-called “linkage factor” which claims that these are not independent events, said Prof. Claoué. “While second eye endophthalmitis after delayed surgery is well described, there is no data to suggest that endophthalmitis in one eye is a risk factor for an increased risk in the second eye. So when people talk about linkage factors and saying that they are not random events, ask them for their data because at present I do not see it,” he said.

To put the statistics in context, Prof. Claoué said that a surgeon would need to operate on every single person in a country with a population the size of Belgium (11 million) in order to stand a reasonable chance of seeing one patient with bilateral simultaneous endophthalmitis.

Charles Claoué: charles@dbcg.co.uk