Screen carefully

Careful screening of at-risk patients can help reduce the incidence of retinal detachment (RD) after cataract surgery, according to José García Arumí MD. “Considering patients’ high expectations for visual improvement after cataract surgery, a surgical complication like a RD is particularly frustrating,” said Dr García Arumí, Instituto de Microcirurgia Ocular, Barcelona, Spain. Rhegmatogenous retinal detachment (RRD) has a four-fold increased incidence in the years after cataract surgery, as compared to the normal population. Pseudophakic RRDs are different to phakic RRDs, as they evolve more quickly and are more likely to develop total detachment. However, they have a similar anatomic and visual prognosis, he noted. Between 10% and 35% of eyes with RRD will have previously undergone cataract surgery. One study suggests that 70% occur within the first postoperative year, while another found a peak around 40 months after cataract extraction. “What is clear, however, is that the increased risk is present up to 20 years after cataract surgery,” he said. UNCLEAR PATHOPHYSIOLOGY But why do they occur so much more frequently after cataract surgery? The pathophysiology remains unclear, but there are several reasonable hypotheses, he said. The induction of a posterior vitreous detachment (PVD) develops shortly after cataract surgery in 79% of eyes without it, which greatly increases the risk of RRD. This might be the reason why post-phaco RRD is more frequent in younger patients, particularly those under 60 years of age, as these patients have not developed a PVD prior to cataract surgery, he explained. It is also thought that enlargement of the vitreous cavity after the removal of the crystal lens may cause changes in vitreous dynamics and thus increase vitreous traction postoperatively. Changes in vitreous composition after cataract surgery, such as its viscosity and macromolecular distribution, have been implicated. Surgeon-related factors have also been identified, said Dr García Arumí. “Increased surgical volume is associated with a lower incidence of RRD thereafter, which might be related to decreased surgical manipulation and release of inflammatory mediators over the vitreous base,” he said. This hypothesis is supported by the fact that the risk has steadily decreased in the past few decades due to improved surgical techniques. Eye-related factors are of great significance and, because they are treatable, deserve a lot of attention. “The odds ratio increases significantly in eyes with an axial length above 23mm. This risk increases further in the presence of peripheral degenerative changes such as lattice degeneration and atrophic holes,” warned Dr García Arumí. As such, he recommended pretreating retinal pathologies that could lead to RD, particularly in younger patients who have not yet had a PVD. However, the benefit of doing so has not yet been proven. “Does prior retinal laser photocoagulation reduce the chances of RRD after cataract surgery? We don’t know for sure, as a Level 1 recommendation, in the form of a randomised study, is lacking,” he said. However, some studies have suggested that prior treatment might be not only unnecessary and ineffective, but also harmful. Dr García Arumí, a vitreoretinal surgeon, recommends examining at-risk patients carefully and treating if retinal pathology that could lead to an RRD is detected. At-risk patients include patients with prior RD or retinal tear in either eye, prior ocular trauma and possibly those with diabetes mellitus. Of course, surgical complications such as posterior capsular break or zonular dehiscence with vitreous are also serious risk factors for postoperative RD. These should be avoided at all costs, and those eyes that suffer surgical complications should be followed up closely. “Whether YAG capsulotomy increases the risk remains controversial,” said Dr García Arumí. He reminded surgeons to counsel patients before surgery of the potential risks and complications of cataract surgery. “RRD risk should not be a reason for not performing cataract extraction when needed, even with identified risk factors,” he concluded. José García Arumí: jgarcia.arumi@gmail.com

Tags: cataract, retina