Causes of Epiretinal Membrane (ERM)

Epiretinal Membrane, Randall Wong, M.D., Retina Specialist, Fairfax, VirginiaAn epiretinal membrane (ERM), also known as macular pucker, is caused by an overproduction of protein which accumulates on the surface of the macula.  An epiretinal membrane (ERM) occurs in normal eyes.

On a microscopic level, the ERM causes the underlying retina to wrinkle or “pucker,” hence the condition is also known as “macular pucker.”

PVD Usually Present

In my experience, something instigates the extraprotein production.  When I examine patients with an ERM, I specifically note the presence or absence of a posterior vitreous detachment (PVD).  There is usually a PVD present in most patients with an epiretinal membrane.

Other “causes” include a previous retinal tear, retinal detachment or a history of intraocular surgery, such as cataract surgery.

Symptoms of Epiretinal Membrane (ERM)

An epiretinal membrane can cause decreased vision and/or distortion.  Remember that the ERM causes the underlying macula to wrinkle.  This directly causes decreased vision and/or distortion.

Not all epiretinal membranes need surgery as either patients are asymptomatic (not aware of any vision loss) and the membrane is not progressing.

Surgery for ERM

Surgery to remove the ERM should occur when you are aware of the blurry vision caused by the macular pucker.  I recommend operating as early as possible due to the fact that usually there is not complete restoration of vision – there may always be some residual blurring or distortion.

Operating early should maximize your visual prognosis.

Timing of Vitrectomy for ERM

Unlike cataract surgery, the timing or indications for vitrectomy to remove the ERM are varied.

Many retina specialists consider the visual acuity as the sole indication for surgery, but this ignores the “distortion” caused by the epiretinal membrane.

Distortion is not measurable and we must rely on your perception of this symptom.




Retinal Detachments Surgery

Scleral Buckle vs. Vitrectomy

Retinal detachment, Randall Wong, M.D., Fairfax, Virginia

This is a recent question I received via email.  It brings up a few good points about choosing scleral buckle vs. vitrectomy to repair a retinal detachment.  I receive many questions via the comments section after an article.  This time, I’m trying something new and making the question a part of the post.


Dear Dr. Randall Wong,

I am not sure whether you do online diagnosis if I send you some
diagnostic data (fundus photo) from my retina doctor. I know online
exam will never be complete, but I wanted the opinion from a highly
regarded retina doctor like yourself.

I was diagnosed with a retinal detachment on the nasal inferior side.
This is a macula on retinal detachment. My doctor used laser to
prevent the detachment from spreading further into the macula. He
couldn’t completely seal off the rest because of the subretinal
fluids. After about 1 week of subretinal fluid not going away, he
recommended scleral buckle surgery but allowed me to look for a second

I did ask about Vitrectomy and he said, there’s high risk for
cataracts and it is more expensive than scleral buckle due to the high
end equipment used.

What is your take on my type of retinal detachment? Should I do
Scleral Buckle or Vitrectomy? I would gladly send my data over to you
if you request them.

Thank you for your time,



Laser Treatment for Retinal Detachment

In this case, it seems that a laser was first attempted to “wall off” the retinal detachment and prevent it from spreading.  The rationale for doing so is similar to containing a forest fire…dig ditches around the fire to prevent the spread.

I personally rarely treat retinal detachments in this fashion.  I don’t feel that there is anything wrong, but I’ve seen too many “walled off” retinal detachments spread, albeit years after the retinal detachment.

In my opinion, simply lasering around the retinal detachment does not fix the problem.

Vitrectomy and Cataracts

Without complicating the matter too much, vitrectomy to repair retinal detachment requires the use of intraocular gas and head positioning after the surgery.  Often, the gas can cause cataract though vitrectomy is an excellent choice for fixing the retinal detachment.

I can’t make a remark about the cost.  You’ll have to check in your own particular area.  I think insurance companies may pay the same or similar rates based upon the fact that the same procedure code is used for scleral buckle and vitrectomy.

Scleral Buckle

There are two ways to use a scleral buckle to repair retinal detachment;  with gas and without.

Scleral Buckle With Gas

After placing the scleral buckle around the eye, gas is injected at the end of the case.  After the gas is injected, proper head positioning is required to keep the gas pressing on the retinal tear.  Remember, the gas can cause cataract.

Scleral Buckle Without Gas

This is the original method used (way back when) to repair a retinal detachment.  The scleral buckle is placed around the eye, no gas is injected and the retina often reattaches.  In this way, gas is avoided and so is early development of a cataract.

What Does This Mean?

I can not make an online diagnosis nor review your case.

For me to make a diagnosis online, without examination, would be impossible.  I get many, many requests for a specific opinion and diagnosis based upon an email or comment on the website.  It’s impossible.  I also want to avoid the liability.

In this case, for instance, I can talk about retinal detachments and my approach to repairing them, but without making specific judgements about this specific patient.

Overall, I can NOT review your specific documentation or studies.  It simply takes too much time, involves potential liability by possibly starting a doctor-patient relationship, and I still can NOT examine you.

On rare occasion, I could be retained to such work.

With regard to fixing the retinal detachment, there are many ways to repair a retinal detachment.

Everyone gets a cataract eventually – with or without retinal detachment surgery.

Retinal detachments can lead to permanent blindness, cataracts do not.

Every effort should be made to repair the retinal detachment without worry to cataract, or even cost.  If all things are equal, then, and only then, would I consider cost.



Retinal Detachments Surgery

Vitrectomy and Scleral Buckle for Retinal Detachment | Retina Specialist Virginia


Retinal Detachments and Retinal Tear

Vitrectomy combined with scleral buckle is the last way to repair a retinal detachment.  This combines two separate methods to repair a retinal detachment.  Both vitrectomy and scleral buckle can be used alone to fix a retinal detachment.

Retinal detachments occur because the vitreous has caused a tear in the retina.  In addition, the vitreous may also be pulling on the retina to cause it to “tent” or detach.

You Are the Vitreous

Let’s pretend you are in the middle of a room with outstretched arms.  The room is the eye and wallpaper is the retina.  You are the vitreous.  Lastly, imagine long, taut pieces of tape extend from the tips of your fingers with the other ends on the wall paper.

If you lean to the left, you’ll pull and cause a tear in the wallpaper attached to your right hand.  If you move to the right, the opposite will happen, you’ll cause a tear to the left.

Scleral Buckle for Retinal Detachment

Whether the scleral buckle goes completely around the eye or is partially installed around the eye does not matter.  Whatever element is used to create the “buckling” effect of the eye, the result is to induce slack in the vitreous by reducing the internal diameter of the eye.

In our example, we are moving the walls of the room closer together. This causes the tape to slacken.  Now, you can lean left or right without tearing the wallpaper due to the slack.  Whatever forces there were pulling on the retina, they have been relieved.

Vitrectomy for Retinal Detachment

Vitrectomy is an intraocular operation where the vitreous is cut away.  Remember, it’s the vitreous which causes tears and exerts a pulling force to elevate and detach the retina.

It makes sense to cut away the vitreous which is pulling on the retina.  Returning to our example, if we simply cut the tape, leaning left or right would not cause pulling on the wall paper.

This is the value of vitrectomy.  It removes the forces of the vitreous pulling on the retina to cause tears and detachment.

After the vitrectomy is completed, it is customary to fill the eye with gas.  With proper head positioning, the gas should prevent redetachment by “plugging” the tears causing the retinal detachment.  The gas doesn’t really push on the retina to reattach.

What Does this Mean?

The best operation to reattach the retina from a statistical standpoint is to perform a vitrectomy with a scleral buckle.  It is the most complicated surgery.  With difficult surgery, however, the complications can increase.

This is probably why most surgeons do not always perform both procedures for all retinal detachments.  The more difficult the surgery, the more chance of complications.

Over the years, I have developed my algorithms, or practice, for certain types of retinal detachments.  In my experience, certain retinal detachments warrant longer and more complicated surgery, but probably yielding better outcomes than if we attempted different procedures.

Maybe this is called experience.



“Other” Eye Conditions Retinal Detachments Surgery

What is Anisometropia?

Image size diffence results from anisometropia, a common cause of double vision following scleral buckle surgery. Randall Wong, M.D.Anisometropia is an imbalance in the prescription needed between your two eyes.  There are several causes of anisometropia, but the most common for a retinal surgeon is a result of a scleral buckle used to repair a retinal detachment.

“Double Vision”

When looking at an object, in most people, we see one single object.  In actuality the left eye and right eye each see something slightly different.  Our brain assimilates each image.  If the images between the two eyes are similar, then we “see” one object.  If the images seen between the two eyes are too dissimilar, then we see double.

If one eye requires a much stronger prescription than the other, you might have double vision due to the large difference in prescription.

Induced Myopia

Every scleral buckle causes in increase in nearsightedness (the ability to see closely without glasses).  After scleral buckle surgery for retinal detachment, the eye elongates, causing the eye to become longer, and therefore, more near sighted.  Over every millimeter longer, there is an increase in 3 diopters of nearsightedness.

Although each eye may have the ability to see 20/20 with separate prescriptions, with both eyes open, the difference may be intolerable.

Inherent with a change in prescription is a change in actual size of the object we are viewing.  Our brain can only tolerate about a 3% difference in the size seen by one eye versus the other.

Cataracts Increase Nearsightedness

A second factor causing anisometropia is cataract.  Most cataracts cause an increase in myopia.  Often intraocular gas is used to help repair the retinal detachment in addition to the scleral buckle.  This intraocular gas can increase the rate of cataract formation and, hence, myopia.

What Does this Mean?

I often get questions on this blog about double vision following retinal detachment surgery.  My own experience tells me that anisometropia is a common cause of double vision following successful retinal detachment repair.

The symptoms are usually ghosting, distortion and double vision.

Contact lens sometimes improve double vision from anisometropia as there is less image size difference with contact lens wear.

True misalignment from the scleral buckle can occur and this needs to be ruled out as a possible cause, too.

My recommendation is to usually see a pediatric ophthalmologist.  These specialists handle all kinds of eye misalignment in both kids and adults.  They are masters at refraction (they refract babies!) and most are well versed in assessing adult cataracts.

Anisometropia due to scleral buckle is a temporary problem.  If, and when, cataract surgery is needed, the intraocular implant (IOL) can be calculated to better match the fellow eye!



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