Cataract outcomes

Corneal refractive surgery patients undergo cataract surgery on average 12 years earlier than other patients, and have a higher risk of ending up with worse vision following cataract extraction, according to data from the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO).

The number of cataract patients with previous corneal refractive surgery is also trending up in Europe, Sonia Manning MD, Dublin, Ireland, told Refractive Surgery 2015: The Annual Meeting of the International Society of Refractive Surgery at the American Academy of Ophthalmology annual meeting in Las Vegas, USA.

Overall, mean corrected distance visual acuity (CDVA) in the two groups was identical before and after surgery, improving from 20/46 before to 20/23 after. However, 8.4 per cent of patients with previous refractive surgery saw no change in CDVA compared with 5.5 per cent of those without (p< 0.001), while 4.0 per cent of those with previous refractive surgery actually saw CDVA decline after cataract surgery compared with 1.5 per cent of patients without (p< 0.001). “We were surprised to see this,” Dr Manning told EuroTimes.

The decline in vision may result from too much positive spherical aberration due to adding an intraocular lens with positive aberration to a cornea that already has induced positive aberration. Dr Manning recommended counselling cataract patients with previous corneal refractive surgery that they have a higher risk of losing some visual acuity after cataract surgery.

Mean age at cataract surgery was 61.8 years for the corneal refractive group, 12 years younger than the mean of 73.8 for the non-corneal refractive group (p< 0.001). Dr Manning suggested several factors that might explain this. Refractive surgery patients as a group may seek surgery earlier because they have a lower tolerance for visual symptoms. Myopes also develop cataracts earlier, and may be over-represented among refractive surgery patients. It is also possible that laser refractive surgery itself may be cataractogenic, she said.

The study examined all cataract surgery cases reported to the EUREQUO database from Europe and Australia from 2008 through to 2013 that included complete demographic, pre-op and post-op visual acuity, and previous corneal refractive surgery status data. It included 592,978 patients without previous corneal refractive surgery and 880 patients with previous corneal refractive surgery, or 0.15 per cent of the total.

The proportion of patients with previous refractive surgery rose each year from 0.06 per cent in 2008 to 0.22 per cent in 2013, which corresponds roughly with the first generation of laser refractive surgery patients reaching cataract surgery age, Dr Manning noted.

Sonia Manning: sonia.sofia1@gmail.com