The retina is a thin sheet of light-sensitive nerve tissue lining the inside of the eye. It is the tissue that turns light into electrical signals which are sent to the brain. In order to function properly, the retina must be attached to the retinal pigmented epithelium (RPE), a layer of supportive cells under the retina.
- Floaters and flashes before the retina detaches
- A gradually enlarging dark area as the detachment occurs
The vitreous is a jelly-like material that fills most of the space inside the eye. It is 99% water, and the gel comes from a protein called collagen. As we age, the vitreous fibers condense, “liquefy” and may pull forward or “collapse.” When this happens, the vitreous separates from the retina. This can result in the eye seeing flashes and floaters.
In some patients the separation can cause a tear in the retina. These tears are often small and located in the peripheral retina, an area which is not typically used for vision. Therefore, decreased vision from a tear alone is highly unusual, and often the only symptoms produced by a retinal tear are flashes and/or floaters. It does not cause pain or redness of the eye. Some small retinal tears may not require surgical intervention.
A retinal detachment is a separation of the retina from the back wall of the eye. When there is a tear in the retina, liquid from the vitreous cavity may pass through the tear, and separate the retina from the RPE. Normal eye movement causes additional fluid currents within the eye which generally causes the detachment to become larger. Once separated from the supporting RPE cells, detached areas of the retina progressively lose vision. Most retinal detachments do require surgery. Depending on the severity of the vision loss, surgery may be scheduled within 24 hours to within 10 days. This timeline is influenced by several varying factors.
Treatment for a retinal tear or detachment is aimed at creating an adhesion between the retina and underlying choroid and RPE. Treatment options will be assessed based on the timing, size and location of the tear or detachment.
With current methods, at least 80-90% of patients can be successfully treated with a single procedure. A total of 90-95% of patients can be repaired with additional procedures. Because some cellular degeneration can occur within hours after a detachment, many people do not get back perfect vision.
Treatment options include:
- Laser Therapy
- Pneumatic Retinopexy
- Scleral Buckle
- Gas Bubbles
- Silicone Oil
This is used to treat retinal tears.
If the tear is posterior enough and there is no intervening vitreous hemorrhage, laser can be used to “spot weld” the retina to the underlying choroid and RPE. Enough burns to create 3-4 rows of laser spots around the tear(s) are made. Topical anesthetic drops are applied and a contact lens is used to focus the laser on the retina. Activity is limited for at least one week until the laser scars become strong enough to be considered “permanent.”
This is used to treat retinal tears.
If the tear is anterior or if there is intervening vitreous hemorrhage that prevents the entire tear from being visualized, the tear is frozen using a cryoprobe. Topical anesthetic is given first, followed by subconjunctival injection of lidocaine (a local anesthetic). Under visualization with an indirect ophthalmoscope, liquid nitrogen is used to freeze around the tear from the outside of the globe. The eye is generally patched for a couple of hours. Activity is limited for up to 2 weeks because the cryotherapy scars take slightly longer to become strong enough to be considered “permanent.”
In this procedure, the causative tear or tears are identified and treated, typically with cryotherapy. A gas bubble is then injected directly into the eye. The patient positions their head so that the gas bubble pushes against the area of the retinal tear(s) for approximately 1-2 weeks. Additional laser may be used to treat the peripheral (attached) retina during the procedure, or later as the gas bubble absorbs and more of the retina reattaches. The success rate is approximately 60% and if the procedure does not reattach the retina, additional surgical methods can be used with excellent success rates and no adverse effects on visual outcome.
Generally this works best in patients without previous cataract surgery, with retinal tear locations in the upper half of the retina. There also should not be any areas of retinal pathology in the lower retina. With modifications of this technique, patients who don’t meet these criteria can also be successfully treated.
In this procedure, the causative retinal tear or tears are located and treated with cryotherapy. A flexible piece of silicone rubber is then permanently sewn to the sclera (white of the eye) to support the area of tears and detachment. This indents or “buckles” the eye helping prevent fluid from passing through the tear. Fluid may be drained from under the detached retina by creating an external incision in the sclera and choroid. Additionally, a small gas bubble may be injected to help keep the retina attached to the buckle while the cryotherapy scars form.
Vitrectomy is a surgical method to treat some types of retinal detachment. It can be used alone or in combination with a scleral buckle in detachments with unusual or difficult features, such as:
- Very large tears
- Scar tissue on the retina
- Excessive blood in the vitreous
- Detachments that failed by other methods.
In this procedure, first, as much of the vitreous gel as possible is removed from the eye. Second, the fluid that has accumulated under the retina is removed to flatten the retina. Third, laser is applied to the peripheral retina and around all tears to help secure the retina in place. Fourth, a long acting gas bubble or silicone oil bubble is placed into the eye to hold the retina in place while the laser and/or cryotherapy scars heal.
Gas Bubbles: A nonexpansile concentration of a long-acting gas (SF6 or C3F8) is used. For most patients, strict postoperative positioning is recommended for 7-14 days. A patient will position their head so that the bubble pushes against the retinal tear(s) while the laser and/or cryotherapy scars form.
Travel by air or to high altitudes is prohibited while the gas bubble is present, as it would expand in the lower atmospheric pressure and severely increase the intraocular pressure. In addition, dental work or general anesthetic with nitrous oxide (laughing gas) is contraindicated because it diffuses into the gas bubble also causing it to expand. Vision is very blurry while the gas bubble is present. Depending on the type, the bubble may remain in the eye for about 2 weeks (SF6) to 2 months (C3F8).
Silicone Oil: If it is impossible for the patient to maintain positioning, or if the detachment is very complex, a clear silicone oil can be used instead of gas. Face down positioning is overnight, and the patient can be in any position other than flat on his/her back while the silicone oil is present. However, this approach necessitates an additional surgical procedure for oil removal approximately 3 months later. Because of the different refractive properties of silicone oil, vision is also very blurry while the oil is present.
Abnormal scar tissue may develop on the retina which will cause the retina to detach after initially successful surgery. This is called proliferative vitreoretinopathy (PVR) and represents a major challenge to retinal surgeons. Other treatments may be done in order to maximize success rates.