Cataract surgery increases the risk of diabetic macular oedema (DMO), medical records from the United Kingdom suggest. An analysis of 4,850 eyes showed that the rate of DMO requiring treatment spiked about 4 months after the surgery.
“There may be, therefore, an argument for providing a further OCT-based assessment, whether in the community or in the hospital eye clinic, at around 4 months post-operatively to screen for the development of DMO, and to provide the opportunity for early treatment,” wrote Professor Alastair K Denniston from the University Hospitals Birmingham NHS Foundation Trust in Birmingham, UK and colleagues.
They published their finding in the British Journal of Ophthalmology.
Cataract surgery increases levels of inflammatory mediators such as prostaglandins, thromboxane A, nitric acid and various cytokines as well as vascular endothelial growth factor (VEGF). But previous efforts to examine the relationship of DMO to cataract surgery have reached conflicting conclusions, the authors write.
These studies had small numbers of patients. To obtain data on a larger sample, Professor Denniston and colleagues analysed records from 19 centres using the same electronic medical records system (Medisoft Ophthalmology, Medisoft, Leeds, UK). Each site is the only National Health Service (NHS) provider of DMO care to their local population, and few patients change providers or get private care, they found.
This system includes a nationally-defined minimum dataset for diabetic retinopathy (DR) that mandates recording of the minimum clinical signs necessary to automatically calculate a precise proxy-ETDRS/International Clinical Grading System retinopathy and maculopathy grade following each consultation.
The researchers looked at eyes undergoing cataract surgery from patients with diabetes, with retinopathy grades recorded in the 2 years pre-surgery and post-surgery, and who had not developed DMO requiring treatment prior to surgery.
They found 1,719 eyes with no apparent DR, 1,034 with mild non-proliferative DR (NPDR), 1,527 with moderate NPDR, 165 with severe NPDR and 405 with proliferative DR.