Tag: pneumatic retinopexy

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Retinal Detachment | Surgery

Featured Image Surgery for Retinal Detachment

A retinal detachment is potentially blinding and will require surgical repair. Despite “success,” visual outcomes will vary depending upon the length of time the retina has been detached and the area of involvement.

The retina is the portion of your eye that contains photoreceptors that respond to light and send visual signals to the brain. Without a functioning retina the brain loses its connection to visual signals from the eye. 

The retina can be detached by a traumatic eye injury, but the most common cause is aging changes such as a thinning retina (lattice degeneration) or changes within the eye’s vitreous humor.

The vitreous humor is a clear gelatinous substance that fills the eye. The vitreous is integral to the normal embryonic development of the eye and its structures. As we age the vitreous humor can shrink and change consistency. As a posterior vitreous detachment (PVD), it can sometimes pull on the retina and tear it. Diabetes and some retinal diseases can also cause retinal detachment.

Retinal Detachment is an Emergency

Whatever the cause, a detached retina is an emergency and must be reattached soon after the detachment to preserve vision. It is an emergency because the retina begins to deteriorate if it is detached too long and every attempt is to prevent the retinal detachment from involving the macula, the functional center of the retina.

Chronic and large detachments have a much worse visual prognosis despite successful anatomic repair.

Symptoms of Retinal Detachment

  • Sudden appearance of many new “floaters” (floating shapes) in your field of vision. It can appear as a shower of black dots, which are blood cells from the retinal tear.
  • Flashes of bright light
  • Loss of vision as though a black curtain has come down across a portion of your field of view

Retinal Detachment Surgery

If there is no retinal detachment, but only a small retinal hole or retinal tear in your retina your eye doctor can repair it with a laser or a sub-freezing probe. This procedure can be done in your eye doctor’s office.

If the retina has detached, you will need surgery to reattach it. There are three common surgeries used to reattach the retina:

Pneumatic retinopexy is also a relatively simple fix even though it is a surgical procedure. It can also be done in your eye doctor’s office. Your eye is numbed, and a gas bubble is injected into your eye that will press against the retina and hold it in place. A laser or sub-freezing probe is also used to seal the retina at the margin of the tear.

Scleral buckling is a surgery to band (retain) the outside of the eye (sclera) from top to bottom. This banding will compress the eye and push the retina back into place where it will reattach to its blood supply.

Vitrectomy is the surgical removal of the vitreous humor. The surgeon will remove any scar tissue and seal retinal tears and then fills the eye with saline, air or a gas bubble. The vitreous does not regenerate, but your eye can function with the substitute for it.

A retinal specialist may often use a combination of these techniques to perform surgery for retinal detachment.

Prognosis

More than 90% of retinal reattachments are successful. If the detachment has not detached the central portion of the retina (macula) that is responsible for fine-detail vision, the restored vision will return to near normal. One reason a detached retina is an emergency is to repair it before the macula detaches.

Prevention

There is no way to prevent age-related retinal detachments, but if you are middle-aged or older a yearly, comprehensive, dilated eye examination may be able to identify eye problems in their early stages.

Diabetics should avoid wide swings between high and low blood sugar levels as a preventive measure for retinal detachments caused by diabetic retinopathy. Diabetics should have a comprehensive, dilated eye exam at least once a year and every six months if retinopathy is detected. 

Randall V. Wong, M.D.
Retina Specialist
Virginia and Washington D.C.

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How I Practice Retinal Detachments

Pneumatic Retinopexy for Retinal Detachment | Retina Specialist, Fairfax, VA

Rhegmatogenous Retinal Detachment with Retinal Tears or Holes
Retinal Tears are Located in the Anterior Retina (Grey Ring)

Pneumatic retinopexy is another method to fix a retinal detachment and is an alternative method to a scleral buckle and/or vitrectomy.

Pneumatic retinopexy was popularized in the 1980’s and has the advantage of being performed in the office.  It is not performed in the operating room as compared to a scleral buckle or vitrectomy – both of which must be performed as operations.

Pneumatic Retinopexy for Retinal Detachments

Every retinal detachment starts with a hole or tear in the retina.  These are so called “rhegmatogenous” retinal detachments.  These are the more common types of retinal detachments.

(Other retinal detachments, such as diabetic retinal detachments or proliferative vitreoretinopathy detachments, do not start with a retinal hole or tear.  These “traction” type retinal detachments are not relevant to this article.)

Retinal detachments develop as fluid migrates from the vitreous to the space underneath the retina.  The retinal hole or tear allows passage of the fluid.  As the fluid accumulates, the retina detaches.

By injecting air or gas into the eye, the passage of fluid may be blocked.  Think of the air or gas acting as a cork to seal the retinal hole or tear.

With proper head positioning, the head is held so that the gas presses against the retinal tear/hole.  Eventually, the retina reattaches and the hole becomes sealed with either freezing (cryotherapy) or laser.

Advantages of Pneumatic Retinopexy

In-Office Procedure – This surgery is performed in the office and avoids the usual rigors of scheduling OR time, etc.  This was the initial attraction to the procedure.  When introduced, most retina specialists preferred using a scleral buckle to reattach the retina – requiring an operation in the OR and much more time.

No Change in Refraction – The shape of the eye remains the same, thus, the refraction should not change.  In contrast, a scleral buckle causes the eye to increase in astigmatism and nearsightedness.

Disadvantages of Pneumatic Retinopexy

Not all retinal detachments can be repaired with pneumatic retinopexy.  Retinal detachments with multiple tears and those with “inferior” retinal tears are less likely to be fixed by pneutmatic retinopexy.

Redetachment rates are higher compared to scleral buckle and/or vitrectomy, probably because the vitreous is left in place and vector forces are not changed, that is, the same forces to pull on the retina and cause a tear are the same.

Cataract formation is higher due to the fact that intraocular gas comes into contact with the lens.

Discomfort – May require a retrobulbar injection to numb the eye.  This can be quite “uncomfortable” in the office setting as we can not offer sedation.

Time – An effective retinopexy can take hours to perform.  Depending upon the amount of subretinal fluid, size of the tear and location, repositioning of the head can only be done slowly.  Often times freezing the tear or laser can be cumbersome.

When I Use Pneumatic Retinopexy to Repair Retinal Detachment

I don’t often choose pneumatic retinopexy to fix a retinal detachment.  It is not my first choice.  I find it quicker and more effective to use a scleral buckle and/or vitrectomy to fix a retinal detachment.  The redetachment rate is lower and I can do a more effective job.

The operating room is a more controlled setting, I have the aid of anesthesia and am able to address any complications or difficulties along the way.

This flexibility is just not possible in the office.

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Retinal Detachments

Gas Injection for Retinal Detachments

Injecting gas into the eye, called pneumatic retinopexy, is the fourth way to fix retinal detachments.  Other methods include

Gas Injection

This procedure is performed in the office.  Similar to other intraocular injections, except gas is introduced into the eye instead of anti-VEGF medications or steroids.

The gas is usually injected at 100% concentration and will expand a bit over the first day or so.  This allows us to inject a small amount of gas that will enlarge and cover more retinal surface area.

Gases used are usually SF6 (sulfur hexafluoride), C2F6 (hexafluoroethane) and C3F8 (octafluoropropane).  These are large molecules, are inert (don’t react with tissue) and can expand at given concentrations.

Their large size means that they will be slowly absorbed after injection, giving us plenty of time to use them as a tool.  In comparison, air, if injected into the eye, does not expand and will be absorbed within 24 hours.

Advantages of Gas Injection

No “operation” is the biggest advantage.  The procedure can be completed within hours of diagnosis.  There are no issues with scheduling an operation at the hospital, pre-operative clearance and coordinating schedules.

Quick Healing – no actual cutting, so tissue healing is very quick.

No Change in Glasses – as the eye remains the same shape (in contrast to scleral buckle), there is no change in glasses prescription.

Disadvantages to Pneumatic Retinopexy

Lower Success Rate – not all retinal detachments can be treated with gas injection.  The forces within the vitreous are NOT changed.

After gas is injected, the head must be positioned so that the gas abuts the retinal tear.  For instance, if the tear is at the “12 o’clock” position of the eye, the head must be held upright, or erect.  Similaryly, if the retinal tear is located at “9 o’clock” as you are looking at the patient, the head must be tilted over to the left to position the gas “bubble” appropriately.

Retinal Detachments and Retinal Tear
A Retinal Tear Can Lead to a Retinal Detachment

For example, in the illustration above, the tear is located at 10 o’clock.  The head should be tilted to the patient’s left, so the gas, as it rises in the eye, will abut the retinal tear.

Usually, only retinal detachments with tears from 8-4 o’clock can be treated with gas.  It is not possible to treat tears occurring at 6 o’clock.

In both scleral buckle surgery and vitrectomy eye surgery, forces are reduced in the vitreous.  This does not occur with pneumatic retinopexy (gas injection).  Therefore, redetachment occurs more often.  The success rate is lower, perhaps around 85% for this procedure.  Scleral buckle and/or vitrectomy procedures are slightly more successful.

Whenever gas is used, there is a higher rate of cataract formation after the operation.  As with any procedure, there is a chance of infection that can cause blindness.

How the Gas Bubble Works

Basically, the gas, when positioned properly, blocks the transmission of fluid through the retinal tear or retinal hole.  The retina reattaches.  By using either laser or freezing (cryotherapy), the tear is treated to induce scarring that will eventually “seal” the retina and prevent re-detachment.  It does NOT “push” the retina back per se.

What Does This Mean? Depending upon the circumstances, there are a variety of ways to operate to fix a retinal detachment.  Gas injection has many advantages, and is a successful way to proceed.

My personal feeling is that gas injection used to be a great time saver, however, the success rate is lower.  As technology as advanced (e.g. 25  gauge vitrectomy), operating room procedures have become easier, and quicker, to perform.  The advantages to pneumatic retinopexy, or gas injection, have become…well, er, “blurry.”

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