Clinical Trial Details
— Status: Recruiting
Administrative data
| NCT number |
NCT04035343 |
| Other study ID # |
18-374 |
| Secondary ID |
|
| Status |
Recruiting |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
August 26, 2019 |
| Est. completion date |
October 2024 |
Study information
| Verified date |
April 2021 |
| Source |
Unity Health Toronto |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Patients may experience metamorphopsia, or image distortion, after having vitrectomy to
repair their rhegmatogenous retinal detachments especially those with a detached macula.
Retinal displacement, as measured on autofluorescence photography, likely contributes to this
distortion. It is thought that the retina slips inferiorly due to the residual subretinal
fluid shifting as the patient transitions from the supine position intraoperatively to the
sitting up position in the immediate postoperative period. By having the patient immediate
position facedown or according to the retinal break, the risk of slippage is theoretically
decreased.
Description:
Rhegmatogenous retinal detachments (RRD) are a sight-threatening condition with an incidence
of approximately 10 per 100 000 people. RRDs can be broadly classified into those with the
macula still attached, and those with the macula detached. Visual prognosis for RRDs with
attached macula tend to be much better than those with detached macula. Pars plana vitrectomy
(PPV) is one of the procedures used to treat RRD. PPV is carried out in the operating room
under regional anesthestic, and often times sedation. The retina is reattached by either
draining the subretinal fluid through a peripheral retinal break, by draining the subretinal
fluid through a posterior retinotomy, or by using a heavier-than-water liquid such as
perfluorocarbon to push out the subretinal fluid. At the end of the surgery, the vitreous
cavity is filled with a substance that will tamponade the retina to the wall of the eye.
Tamponade agents can be temporary, such as sulfur hexafluoride (SF6) and octafluoropropane
(C3F8), or long term, such as silicone oil. After the surgery, patients are usually told to
put their facedown allowing the tamponade agent to keep the macula attached while the
remaining subretinal fluid is reabsorbed by the retinal pigment epithelium. Alternatively,
some surgeons ask that their patients position according to the location of their retinal
breaks with the aim for the buoyant gas bubble to cover the break or breaks. Patients may
experience metamorphopsia, or image distortion, after having their RRD repaired especially
those with a detached macula. Retinal displacement, as measured on autofluorescence
photography, likely contributes to this distortion. Supine positioning in theory covers all
break locations as usually breaks occur in the anterior part of the retina near the vitreous
base. This position has the advantage of being more ergonomic than face down. Depending on
the results, this study might provide evidence for the current standard of care, which is
face down positioning for the first day after vitrectomy for retinal detachment. Or, if
supine positioning demonstrates superiority in reducing the risk of retinal displacement,
patients would be able to maintain a more comfortable position after surgery.
