Eyeworld

EW RETINA 72 December 2016 by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer hazard ratio shows the ratio of the risk in the operated eye to the non-operated eye. This was the most relevant thing we could do because eyes in young individuals who had cataract surgery were different from normal eyes." Using older female patients who had a very low risk of pRD as the standard, Dr. de la Cour showed that young males had a significant- ly increased risk in the operated and fellow eye, compared to this group. The pRD hazard ratio was 4.2 (P<0.001). There was no sig- nificant difference between males and females, or between age groups in males. Young females showed a significantly higher risk than older females (P=0.03). The operation in- creased the risk of RD by almost the same fraction in young as in older individuals. "While it is still true than young males have a significantly increased risk of developing pRD, the risk is in both eyes. The operation multiplies that risk by a factor of four. It does that in young males and in older female patients, but as older females have a much lower risk to start with, their final risk of RD is also lower." Blaming surgery "We may want to ask at this point, 'If you have a patient with pRD, how much of the risk of RD can be attributed to the surgery itself?' Our data allows us to make a relatively precise estimate of that. Once you have a pRD within 6 months after surgery, about 90% of that risk can be attributed to the surgery. Once 2 to 5 years pass, this risk stabilizes at about 70%, but after 5 years, you still have an attributable risk that is significantly above 50%. This has legal implications in Denmark." The implication of cataract surgery for the overall occurrence of RD is shown in an epidemiological study of 411,140 cataract operations performed in public and private Danish hospitals between 2004 and 2012. 2 The data reveal that cataract surgery is on the rise in Denmark. The mean time between first eye/ fellow eye surgery has rapidly decreased down to a few weeks, making Dr. de la Cour's previous study results unfeasible because the risk time has evaporated due to the diminished time between RD devel- opment of the two eyes. the two eyes in the interval between cataract surgeries, with the patient serving as his own control. The risk of pRD attributable to the surgery could therefore be calculated under the assumption that the two eyes have an equal inherent risk," he explained. Patients were followed until they were censored, i.e., got a retinal detachment, died, the study ended, or underwent any other type of sur- gery that might pollute the picture. He found 575 retinal detachments during the follow-up period, of which 465 were on the primary eye and 110 on the control eye. "The risk of RD was vastly in- creased in the young age groups. So there is something in young patients that undergo cataract surgery that increases the risk of RD in both the operated eye and the non-operated eye. Although this may not come as a surprise, it is never really ad- dressed," he said. Male patients younger than 60 years who have had cataract surgery had a five-fold higher risk of RD in their non-operated fellow eye compared to men in the background population. This risk was increased by a factor of three in female pa- tients. Young men had a significant- ly higher risk of retinal detachment in the operated eye of roughly 1% compared to the background popu- lation, Dr. de la Cour said. Using a hazard ratio to nor- malize the risk, he explained, "The sex matched controls, especially in younger individuals, and that there may be something in the genetic makeup of those individuals that de- velop cataract that also make them prone to retinal detachment," Dr. de la Cour said. "To assess the risk that can be attributed to phaco surgery, we needed a better control group. The question was whether we were being tricked into thinking that the risk of pRD really increased after cataract surgery by the use of the wrong control group, which would give us a skewed reference." Addressing this, Dr. de la Cour and his team of investigators stud- ied pRD using data from 202,226 patients from the Danish National Patient Registry, 1 which holds infor- mation on all surgeries performed in Danish public and private hospitals, including all surgeries for RD. The retrospective, register-based cohort study included patients who had undergone uncomplicated phaco surgery as well as RD surgery from January 1, 1996 to June 30, 2011. Patients were included if they had registered primary phaco surgery with lens implantation on their first eye and were more than 40 years of age, and excluded if they had trauma surgery, vitreoretinal surgery, anterior vitrectomy, or cataract sur- gery in the other eye. "The fellow non-operated eye was used as a reference, not the general population. The idea was to examine the development of RD in What is to blame for rhegmatogenous retinal detachment? A ccording to pseudopha- kic retinal detachment (pRD) specialist Morten de la Cour, MD, professor of ophthalmic surgery, University of Copenhagen, and chairman of the eye department, Rigshospitalet, Glostrup, Denmark, the incidence of pRD in Denmark has increased along with the num- ber of cataract operations performed. While the operated eye stands a five times higher risk of developing pRD following surgery compared to the non-operated eye, even the fellow eye has an increased risk of developing RD after cataract surgery by a factor of 1.3, he explained in a lecture he gave on pRD at the 2016 German Ophthalmological Society meeting in Berlin, Germany. Risk of pRD "The risk of pRD is five times higher in an individual's operated eye than in the non-operated fellow eye," Dr. de la Cour said. "When you look at the risk of pRD that is associated with cataract surgery, young age and male sex are weak risk-modifiers for pRD. In younger patients undergo- ing cataract surgery, the risk of RD in the non-operated eye is higher than in the background population, meaning that we should not use the background population as a control group when assessing the risk of RD that is associated with cataract sur- gery. The risk of pRD attributable to the surgery is significantly increased for at least 10 years after cataract surgery and remains as high as 50% for 5 years after the operation, our studies have shown." Søren Solborg, MD, PhD, and Dr. de la Cour studied the long-term incidence of rhegmatogenous retinal detachment in 6,000 individuals un- dergoing standardized phacoemul- sification surgery, within a 6-year time period, and found that the risk of retinal detachment was linear. This led them to investigate whether the increased risk of RD in the years following surgery was still associated with cataract surgery. "We began to think that eyes that develop cataract may be 'dif- ferent' from normal eyes in age and Pseudophakic retinal detachment: The blame game Presentation spotlight 25-gauge vitrectomy for repair of retinal detachment without scleral buckling Source: Steven Charles, MD

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