Types of Retinal Detachments
When consulted about a patient with flashes and floaters, here are some of the possibilities that you may find.
|Rhegmatogenous Retinal Detachment|
A rhegma, a full thickness retinal break, has allowed fluid underneath the retina leading to a detachment.
|Tractional Retinal Detachment|
Tractional forces, usually due to preretinal fibrosis, has led to detachment from the pulling forces due to contracting scar tissue .
|Serous Retinal Detachment|
Fluid accumulation underneath the retina happens without a retinal break, usually in localized or multifocal areas.
|Retinal Tears and Holes|
This is not a retinal detachment, but also presents with symptoms of floaters and flashes. These happen in the retinal periphery. Treatment of retinal tears, usually with laser retinopexy, is indicated to prevent progression to a retinal detachment.
|Posterior Vitreous Detachment|
This is not a retinal detachment, but also presents with symptoms of floaters and flashes. Progression of PVDs can lead to horseshoe tears as the detaching vitreous face pulls on the retina.
11 Clinical Exam Points
- High myopia – myopes are at higher risk of tears and detachments because a posterior vitreous detachment develops earlier, the peripheral retina is thinner, and lattice degeneration occurs more commonly.
- History of retinal detachment – the risk of another retinal detachment is substantial. There is an overall 10% chance of having another retinal detachment in the fellow eye in phakic patients and a 20% chance if the fellow eye is pseudophakic. Anyone with new RD symptoms with a history of RD should be examined very carefully.
- Recent eye trauma – about 15% of retinal detachments are caused by eye trauma, so this is a very important risk factor to keep in mind, especially for younger patients.
- Cataract surgery – recent cataract surgery increases the risk for retinal detachment. This risk is higher in high myopes who are getting cataract surgery, if there was intraoperative vitreous loss, or after getting YAG capsulotomy. Also, pseudophakic patients may be more difficult to examine because of optical aberrations near the edge of the IOL or have a poorly dilating pupil.
- The fellow eye – if you found a retinal detachment in one eye, make sure to examine the fellow eye for treatable disease like lattice degeneration or asymptomatic retinal tears which warrant treatment.
- Schaffer sign or tobacco dust – when fine pigment is seen in the anterior vitreous, this increases the suspicion for a retinal break.
- Posterior vitreous detachment – a symptomatic PVD may be the reason for the patients new floaters and flashes. As the PVD continues to evolve, it may lead to more retinal traction causing new tears. That’s why it’s important to bring the patient back for a repeat exam in 2-4 weeks.
- Lattice degeneration – about 5-10% of the population has some lattice degeneration, and it’s more common with high myopia. The vitreous has more liquefaction over the lattice degeneration, and there are also focal strong vitreoretinal attachments at the edge of lattice. This leads to an increased risk for a tear happening with entry of fluid underneath the retina.
- Vitreous hemorrhage – a hemorrhagic PVD is associated with about a 70% risk for a retinal tear. It’s caused by a retinal blood vessel being torn due to the vitreoretinal traction forces. If the blood is too dense see through, you may need to use ultrasound and frequent serial exams.
- Ruling out a tear, break or detachment – take your time to look in all directions at the retinal periphery. In addition to retinal detachments, peripheral findings leading to RD symptoms may include horseshoe tears, giant retinal tears, operculated holes, retinal dialyses, and other peripheral findings.
- The scleral depressed exam – may help you uncover anterior retinal tears, retinal dialyses, vitreoretinal tufts, meridional folds, or other pathology.
Macula-off or Macula-on?
This is an important distinction because it changes management, choosing between an urgent or an emergent case. It can be challenging for a beginning resident to figure out the difference. Macula on retinal detachments always maintain normal central visual acuity while macular detachment leads to vision worse than 20/200. Fundus exam may show macular folds, a whiter color of the retina, changes in elevation of the retina, or a demarcation line between attached and detached parts. Ancillary testing can be used if they are available, such as OCT, B-scan ultrasound, and fundus photographs to take a close look at the macular details.
Treatment Options for RRDs
The posterior segment is entered via pars plana ports. The vitreous is removed and the retina is flattened by removal of the subretinal fluid through: heavy perfluorocarbon liquids, subretinal drainage through an existing retinal break, or creation of the drainage retinotomy. After the retina is flattened, strong chorioretinal adhesions are created usually with endolaser to tack the retina down. Finally, an intraocular tamponade agent is used to hold the retina flat while the laser scars form.
This involves an encircling or segmental buckle placed around the eye which indents the sclera closer to the detached retina. This changes the fluid dynamics, tractional forces and other anatomical relationships which helps reappose the retina. An external drainage incision can be used to drain the subretinal fluid, flattening the retina. With scleral buckling, cryotherapy is used to create chorioretinal adhesions which prevent future detachments.
This outpatient procedure is quicker and more comfortable to the patient. It involves laser or cryo retinopexy followed by injection of intraocular gas as a tamponade agent. Patient selection is important to success: those with superiorly located, single break, detachment in only 1 quadrant, and are phakic are more favorable candidates.
- Ghazi NR and Green WR. Pathology and pathogenesis of retinal detachment. 2002. Eye; 16: 441-421.