Background and study aims The retina is the layer at the back of the eye that allows us to see. Sometimes, it can detach from the wall of the eye, causing a condition called rhegmatogenous retinal detachment (RRD), which leads to vision loss and requires surgery. The most common surgery for RRD is vitrectomy, but this can lead to complications like cataracts, which worsen over time and need to be removed with another surgery. Cataract surgery involves replacing the cloudy lens with a clear artificial one. Currently, it's unclear whether it's better to perform both surgeries at the same time or separately. The COMBAT study aims to find out which approach is best by comparing the outcomes of patients who have vitrectomy alone versus those who have both surgeries (vitrectomy and cataract surgery by phacoemulsification and intraocular lens \[IOL\] implantation) together.
Who can participate? Adults aged 50 and older who have RRD but are not highly myopic (less than -6 diopters or an axial length of 26.5 mm or less) and have not had previous vitreoretinal surgery. Participants must be scheduled for a pars plana vitrectomy to repair their RRD.
What does the study involve? Participants will be randomly assigned to one of two groups: one group will have vitrectomy first and, if needed, cataract surgery later; the other group will have both surgeries at the same time. The study will compare their vision, the number of successful retina reattachments, health related and visual related quality of life, patient satisfaction, complications, additional surgeries and procedures, and costs.
Adults ≥50 years of age
Non-highly myopic (< -6 diopters; ≤26.5 mm axial length) phakic RRD
Naive to previous vitreoretinal surgery
Pars plana vitrectomy is planned to repair their RRD
Presence of a "formed/established cataract." A "formed/established cataract" is defined as a cataract that, based on the Age-Related Eye Disease Study (AREDS) Research Group, is graded as nuclear sclerosis of >3 and/or if there is an anterior cortical cataract and/or a subcapsular posterior cataract involving the visual axis.
Pseudophakia or aphakia
High myopia (≥ -6 diopters; >26.5 mm axial length)
Giant retinal tear (i.e. presence of one or more retinal tears of >3 clock hours in size)
Parallel
Phacovitrectomy
Procedure/SurgeryParticipants will undergo phacovitrectomy to remove the lens (phacoemulsification and intraocular lens implantation) and to repair the RRD (vitrectomy). Although a phacovitrectomy is done in the same manner whether the condition to be treated is macular hole or RRD, the calculations required for the surgeon to select which intraocular lens should be implanted are different if there is a RRD with a detached macula. For this reason, a Standard Operating Procedure (SOP) will be prepared for the phacovitrectomy group to guide surgeons on how to best determine the intraocular lens under these circumstances (17). Vitrectomy with any gauge size (e.g.23g, 25g, 27g) will be allowed for the surgery, as per standard care at the participating site. The choice of the tamponade agent will be at the discretion of the treating vitreoretinal surgeon, as per standard care.
Vitrectomy
Procedure/SurgeryParticipants will receive vitrectomy to repair their RRD. The vitrectomy would be done as per standard care. Vitrectomy with any gauge size (e.g.23g, 25g, 27g) will be allowed for the surgery, as per standard care at the participating site. The choice of the tamponade agent will be at the discretion of the treating vitreoretinal surgeon, as per standard care. Then, if a cataract develops, phacoemulsification and intraocular lens implantation will be done as per standard clinical practice.
Best-Corrected Visual Acuity (BCVA)
Change in Best-Corrected Visual Acuity (BCVA) in the affected study eye from baseline to 52 weeks (+/- 6 weeks) after surgery (equivalence margin +/- 7 ETDRS letters)
Primary anatomical success
Proportion of eyes with an attached retina after one vitrectomy
Final anatomical success
Proportion of eyes with an attached retina after two or more vitrectomies
Intraoperative complications
Total number and by severity score
Postoperative complications
Total number and by severity score
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Queen's University, Belfast
Lead sponsor
Northern Ireland Clinical Trials Unit
Collaborator
