Category: Treatments

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Glaucoma Treatments

A Biodegradable Implant for Glaucoma

Featured Image for Sustained Release Implant Treats Glaucoma | Retina Eye Doctor
Featured Article Image | Durysta | RetinaEyeDoctor.com

Novel Durysta improves compliance for treatment of glaucoma.

Sustained release technology solves an old treatment issue—patients who don’t take their medicine or don’t take it properly.

Durysta™ was approved by the FDA in March of this year to deliver medication to control open-angle glaucoma. It is the first implantable sustained-release delivery system for reducing intraocular pressure.

Biodegradable Implant for the Eye

Durysta is a tiny implant smaller than a grain of rice. It comes preloaded in its own injection delivery system. The implant is placed underneath the cornea, on the edge of the iris where it will deliver intraocular pressure reducing medication to the exact area it is needed. Once the medication is all dispensed the implant biodegrades. 

Implants are made biodegradable by using compounds present in nature to create polymers. These polymer plastics degrade, and the body naturally eliminates the wastes.  The system is very similar to Ozurdex, a sustained release platform used to treat complications of diabetic retinopathy and retinal vascular occlusions.

The implantation is not painful and can be done in a doctor’s office.

Implant Release Bimatoprost

The implant releases Bimatoprost, a drug that lowers intraocular pressure by increasing the outflow of aqueous humour. While the drug has been used as pressure-reducing eye drops since being approved by the FDA in 2001, the sustained release formulation is novel.

Advantages of Implanted Sustained-Release Medication 

Non-adherence to glaucoma treatment has been a problem for many years. Reports vary, and non-adherence has been reported to be from 30% to 80% of patients treated. Having an implant that delivers the medication will eliminate the issue of non-adherence in the patients receiving the implants.

How does Glaucoma Damage Eyesight?

A buildup of fluid (aqueous humor) causes eye pressure to increase. The increased eye pressure damages the optic nerve causing it to gradually deteriorate. 

The first symptoms of this optic nerve deterioration is a subtle loss of peripheral (side) vision.

Damage to the optic nerve is irreversible. The cable of nerve fibers that carry visual signals to the brain do not have the ability to regenerate or heal. That’s why it is important to begin treating glaucoma before any vision loss occurs.

How is Glaucoma Diagnosed?

The presence of glaucoma can be discovered during a routine eye exam. 

In the early stages, before it causes any vision loss, glaucoma has no symptoms. Having regular eye exams can detect glaucoma in the very early stages and treatment to lower eye pressure can be started.

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

Categories
Testing Treatments

What is OCT? | Optical Coherence Tomography

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OCT stands for optical coherence tomography and is an important diagnostic tool used by most eye doctors, but is exceptionally useful to the retina specialist.

OCT can be used alone to study the retina or in conjunction with a variety of other testing modalities to include retinal digital photography and fluorescein angiography.   This non-invasive test may be used to help diagnose and treat glaucoma and retinal diseases although the testing procedure is not exactly the same.

The test provides information in “high-definition” due to its ability to examine and provide information down to the micrometer level.  Before OCT, this resolution of testing was not possible.

Optical coherence tomography may be performed on the retina and separately focused on the optic nerve (glaucoma).

This article focuses on OCT for retinal diseases and how it has become the mainstay of diagnostic testing which offers different information than a fluorescein angiogram.

What OCT

This is a painless non-invasive test using light waves to examine the different layers of the retina.  The surface topography can also be examined.

By the way, tomography allows us to examine a tissue in cross-section, whereas topography allows us to examine the surface of a tissue.

Results of an OCT are best if the pupils are dilated, but dilation is not necessary.

An OCT is obtained by placing resting your chin on the machine while keeping your eyes and head as still as possible.  Nothing will touch your eyes.

The scan will take several minutes while you look at a target keeping your eyes still.

When to Use OCT

OCT is very useful to the retina specialist to evaluate common retinal diseases such as:

  1. Macular holes
  2. Macular pucker
  3. Macular edema caused by various conditions such as retinal vascular occlusions (RVO)
  4. Macular degeneration (ARMD)
  5. Central serous retinopathy (CSR)
  6. Diabetic retinopathy
  7. Vitreomacular traction (VMT)

Optical coherence tomography is extremely useful in monitoring the effectiveness of a treatment and answers the question, is the patient getting better?

OCT has a few limitations.  The test is very difficult to perform in situations where light is blocked from entering the eye, such as:  dense cataracts or vitreous hemorrhage.

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Categories
Macular Degeneration Retinal Vascular Occlusions (RVO) Treatments

Beovu for Wet Macular Degeneration

Featured Image Beovu
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A new drug, Beovu (brolucizumab), is now FDA approved for the treatment of wet macular degeneration.  Beovu, manufactured by Novartis, is an anti-VEGF injection. Like other anti-VEGF injections, Beovu may be used in patients requiring multiple treatments, but at a more extended dosing schedule.

Macular Degeneration

There are two types of macular degeneration:  wet and dry.  

Dry macular degeneration usually progresses quite slowly (over months to years) and leads to minimal to moderate vision.  There is no treatment for dry macular degeneration.

Wet macular degeneration can be more aggressive causing loss of vision over days to weeks.  Abnormal blood vessels (neovascular blood vessels) can develop within the layers of the retina.  These vessels lead and bleed, hence the term “wet.”  

Anti-VEGF medications selectively target the neovascular tissue thereby limiting damage to the adjacent normal retinal tissue.

If caught in time, vision loss from wet macular degeneration can be improved.  Treatments are then aimed at reducing the chances of recurrence.

Anti-VEGF Treatments

All anti-VEGF treatments decrease leakage and can cause regression of the neovascular tissue.  All can be repeated as often as monthly.

Other anti-VEGF injections include:  Avastin, Lucentis, Eylea and Macugen.

Anti-VEGF injections have become the mainstay of treating diabetic retinopathy, retinal vascular occlusions and wet ARMD.  All are similar in that both leakage and bleeding can occur.

BEOVU – Extended Dosing

Beovu was compared to Eylea and was found to be “non-inferior” with respect to vision improvement.  Beovu, however, is approved for a 3 month dosing schedule and may represent a unique advantage for retina specialists’ use compared to other anti-VEGFs on the market.

In short, Beovu may work as well as other anti-VEGFs, but may be injected every 12 weeks instead of every 4-6 months.

Though FDA approved, it is likely that use of Beovu will be slow as retina specialists identify exactly which patients will benefit the most from this new treatment for wet macular degeneration. 

 

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Retinal Detachments Treatments Video

Total Retinal Detachment Repaired with 25 gauge Vitrectomy

Retina Specialist | Retinal Detachment | Northern Virginia | Washington DC
This video was recently published to my YouTube channel.  This patient had a complete retinal detachment in the right eye having lost central vision within a week of arriving to my office.

This retinal detachment was repaired with a 25 gauge vitrectomy and gas.  The patient was awake, but the eye was completely numbed.  The surgery took place at Woodburn Surgery Center in Annandale/Fairfax, Virginia.

 

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Vitrectomy for Retinal Detachment

Vitrectomy alone has become very popular for repairing a retinal detachment.  Other choices include pneumatic retinopexy (an in-office procedure), scleral buckle, or vitrectomy with scleral buckle.

Retina specialists differ in their own preference for certain techniques.  I often choose vitrectomy alone or vitrectomy with scleral buckle.  These are the two most successful methods.  Remember, retinal detachments aren’t always fixed the first time and are sometimes not fixable.

The vitrectomy requires installation of 3 ports or trocars.  Two ports are reserved for each hand and the 3rd port is hooked up to a tube which keeps the eye pumped with either saline or air.

With 25 gauge vitrectomy systems, as in this case, the blue trocars are simply pushed into the eye.  The holes are so small that they are regarded as self-sealing.  Sutures are not required at the end of surgery and healing is much faster.

The first step of the vitrectomy is to remove the vitreous.  You can note a PVD, complete detachment of the retina, two holes/tears and detachment of the macula.  The patient barely has a cataract and has not had cataract surgery.  As I move around the eye, I am also examining the retina looking for all possible tears or holes which led to this “rhegmatogenous” retinal detachment.

Rhegmatogenous retinal detachment are the most common and are caused by holes, or “rhegma,”

Macular Detachment

At the start of the operation, note how difficult it is to see the macula.  As the retina becomes “less detached” the typical brown/yellow appearance of the macula becomes more apparent.  The macula is the functional center of the retina and provides the capability of us to see 20/20.  The remaining portions of our retina provide peripheral vision.

Macular detachment can alter the visual outcome of surgery.

Fluid-Air Exchange

After I have identified the two tears and marked them with cautery (turning the tissue white), I also created a 3rd hole called a retinotomy.

Drainage of the sub-retinal fluid occurs through the 3rd hole (retinotomy).  Sometimes if a hole or tear is more conveniently located, I can skip the part of a retinotomy.  At the end of the fluid-air exchange, the retina is completely attached.

The gas will be absorbed slowly over the next two weeks.  Retina specialists vary as to the type of gas and mixture (concentration) used.  I commonly use 16% SF6.  Other gases/mixtures can take longer.

As the gas is absorbed, there is always a concern of the retina detaching again.

Laser Treatment

Having identified and marked all the tears, I can easily see where to use/aim the laser.  When the fluid-air exchange is completed, unmarked retinal holes can become invisible.

The idea of laser is to induce scar formation to the layer underneath.  This prevents redetachment from the same tears as the gas is absorbed by the eye.

The key to successful retinal detachment surgery is identifying all the tears and treating them all successfully.

Air-Gas Exchange

The very last step of the operation involves replacement of the air with a special inert gas.

The gas will be absorbed slowly over the next two weeks.  Retina specialists vary as to the type of gas and mixture (concentration) used.  I commonly use 16% SF6.  Other gases/mixtures can take longer.

As the gas is absorbed, there is always a concern of the retina detaching again.

 

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