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“Other” Eye Conditions Retinal Detachments

Retinal Tears and Vitreous Hemorrhage

Vitrectomy for Retinal Tear to Remove Vitreous HemorrhageA vitreous hemorrhage may be caused by a retinal tear.  Sometimes there is so much blood in the eye that direct examination is impossible and we can only guess at the most likely cause.  It is the most difficult situation for me to handle as a doctor.

Patients lose significant vision as the blood in the middle of the eye physically blocks all light from hitting the retina.  While this is usually not permanent visual loss, the blood makes it difficult to make a definitive diagnosis as it can be impossible to see the retina.

Normally, without blood in the eye, a retinal tear may be easily diagnosed and treated with laser.

While there are other causes of vitreous hemorrhage, such as diabetic retinopathy, retinal vascular disease and others.  Still, a retinal tear causing the vitreous bleeding is quite likely.

Retinal Tears Cause Retinal Detachments

A retinal tear can cause a retinal detachment.  A retinal detachment is potentially blinding.

In cases of vitreous hemorrhage, the patient cant’ see “out” and I can’t see “in.”  My ability to examine the eye is hindered.

Options at this point are to observe (i.e. do nothing).  Observing the eye is okay as the blood is doing no harm.  But what if there is a retinal tear?  A retinal detachment could occur if there is an undiagnosed retinal tear.

Other tests, such as an ultrasound can often detect a large tear, but it is not as good as directly examining the eye.  Operating to remove the blood to facilitate proper examination is an option, too.

What Does This Mean?

I am getting older, more aggressive, but smarter.

As I have aged, i.e. gained more experience, I have become more comfortable operating in these cases.  When I was younger, I would often hesitate because I was uncomfortable offering surgery in a situation where surgery might not be necessary, but I’ve learned (through experience) that watching a waiting can be more problematic.

Most of the time I recommend operating to at least remove the blood and confirm a diagnosis.  The risks of modern vitrectomy are quite low, while the risk of a retinal detachment occurring while we are waiting is quite possible.

Vitrectomy surgery is usually performed as an outpatient.  If a tear is indeed present, it can be treated simultaneously.

At the very least, a diagnosis can be made and a potentially blinding condition avoided.

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Diabetic retinopathy Testing

How To Diagnose Diabetic Retinopathy

The retina is the only part of the eye affected by diabetes.  The only way to diagnose diabetic retinopathy is by direct visualization of the retina.  Your eye doctor should be able to dilate your eyes and, by simply looking at your retina, diagnose the disease.  That’s all.

No Symptoms of the Eye Disease

Symptoms are the effects of a disease.  These are what a patient feels, not what a doctor sees.  Complaints of blurry vision, pain, shortness of breath, nervousness…all are types of symptoms.

The disease, diabetic retinopathy, can cause mild blurriness to complete blindness, or nothing at all.  Many patients see perfectly, yet have the disease.  They just don’t know it.

This is the danger of diabetic retinopathy.  Just like high blood pressure, it may cause absolutely no symptoms.

No Diagnostic “Tests”

A normal eye exam does not always include dilation of the pupils.  Every diabetic patient must have the pupils dilated at least annually.  These are the recommendations of the American Academy of Ophthalmology and the American Optometric Association.

Why?  A dilated exam is the only way to examine the retina.  A dilated exam is the only way your doctor  can “see” the characteristic changes of diabetic retinopathy.  There are no diagnostic tests for diabetic retinopathy.

In the absence of symptoms, the diabetic retinopathy can still be diagnosed.  Early detection means preventing loss of vision.

Fluorescein angiography and OCT (optical coherence tomography) are used commonly to study some of the aspects of your retina (i.e. is there retinal swelling?), but neither are necessary for the diagnosis.

The only way to diagnose diabetic retinopathy is for somone to “see” it.

What Does This Mean? Diabetic eye disease can be “silent.” Many people believe that the absence of symptoms means the absence of disease.  Obviously not true.

The patients with whom I have had the most trouble (i.e. they go blind despite my intervention) have had either no symptoms or ignored themselves for an extended period.  Certainly, they never had an eye exam until it was too late.

Sadly, in almost all cases, the blindness could have been prevented if someone had just “looked.”

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Diabetic retinopathy Treatments

Iluvien Treatment for Diabetic Macular Edema

Iluvien gets closer to FDA approval for treatment of diabetic macular edema.  Earlier this week, I wrote about emerging treatments for diabetic retinopathy.  Of the group, Iluvien is now the most likely to be available.

Alimera Sciences has filed for NDA (New Drug Application) for Iluvien.  In March, the company announced the favorable results in their clinical trials for the FDA.  The NDA is the last step for FDA approval.

Iluvien Releases Steroid

Iluvien is a sustained release drug delivery system.   Similar to Ozurdex, the delivery system will release steroid after injection into the eye.   (Ozurdex is presently FDA approved for retinal vein occlusions, not diabetic retinopathy.  The makers of Ozurdex are hopeful that it may be used for diabetes.)

The steroid released by Iluvien, fluocinolone, will last for 24 months after injection.  The vehicle will remain in the eye after the drug is released.

Alternative to Present Treatments

The present treatment for diabetic macular edema involves laser treatment, anti-VEGF injections and/or steroid injections.  The laser treatment has limited applications, that is, it can’t be used in all patients and also doesn’t work as well as any of the injections.

The injections, on the other hand, don’t last long and need to be repeated.

Iluvien may obviate the need for repeated treatments and offer significant improvement in vision compared to the standard laser therapy.  With fewer injections, there is less chance of infection.

What Does This Mean? Ozurdex was FDA approved about one year ago.  The significance of Iluvien’s NDA is the validation of the advantages of intraocular sustained release drug systems.

All emerging treatments for diabetic macular edema involve injections.  All seem to offer superior treatment compared to the standard of care, laser photocoagulation.  A sustained release system for diabetic retinopathy will change the way we treat this very common eye disease.

The introduction of Iluvien is estimated to be towards the end of the year according to this week’s press release.

I can’t wait.

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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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