Tag: Myopia

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“Other” Eye Conditions Retinal Detachments

Double Vision After Retinal Detachment Surgery

Updated by Mike Rosco, MD on 3/13/23 at 6:19 PM

Double Vision Can Follow Retinal Detachment

Decreased vision and double vision (aka diplopia) after retinal detachment surgery may occur, yet is not common.  The perception of “double” is more common than actually seeing two of everything.  There are several causes for really seeing two images following retinal detachment surgery.

Scleral Buckle May Cause Diplopia

A common method to fix a retinal detachment involves the use of a “scleral buckle.” This involves placing a belt, usually silicone rubber, on the outside of the eye and underneath the overlying eye muscles (see diagram below). Though the buckle assists in lowering the risk of a redetachment, it also will elongate your eye. The visual effect of this elongation is an increase in myopia (nearsightedness) and/or astigmatism.

Scleral Buckle for Repair of Retinal Detachment

The glasses prescription for the operative eye will change after scleral buckle surgery.  Large prescription differences between the two eyes leads to a condition called anisometropia.  Due to this large prescription imbalance, the brain cannot successfully fuse the two images into one size. 

Why? Inherent to large changes in prescription is a change in the actual size of the image that we see.  Thus, with a large prescription disparity between the eyes, the brain actually sees two different sized images.

This is probably the most common cause of “double vision” after retinal detachment surgery.

Of note, at times, manipulation of the eye muscles can cause true double vision. The muscles may get injured or impaired such that the eye does not move in coordinated fashion with the other eye.  Diplopia can occur from this muscle imbalance

Cataracts Can Cause Diplopia

Gas is commonly used to repair a retinal detachment.  A common side effect of intraocular gas is the hastened formation of a cataract.  This, too, can change the prescription of the eye dramatically.  “Double vision” can result from cataract formation by causing a strong shift in the prescription (the way the light is focused as it enters the eye). 

What Does This Mean? There are many causes of decreased vision following retinal detachment surgery and many are described as “double vision.” However, true double vision, where the eyes are misaligned after surgery, is quite uncommon after retinal detachment surgery.  Many cases of double vision are actually caused by changes in the prescription, either due to physical changes of the eye from the scleral buckle or due to advancing cataract.

Happily, most cases can be fixed.  If the retina is functioning well enough for the double vision to be “seen,” then it is likely that corrective measures can be taken.

For anisometropia (double vision due to a large difference in prescriptions between eyes), a contact lens can be fitted to assist with making the eye prescriptions more similar. Cataract extraction with implantation of a new intraocular lens is an option if the eye’s natural lens changes after retinal detachment surgery. Finally, for cases of “true” double vision due to eye misalignment, eye muscle surgery can help position the eyes into alignment once more. 

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Retinal Detachments

Decreased Vision Following Retinal Detachment

Updated by Mike Rosco, MD 3/26/23 6:14PM PST

There are many reasons why your sight may be poor following retinal detachment surgery.  Obviously, it is possible that the disease actually led to loss of vision as retinal detachments can lead to blindness.   There are, however, other less serious reasons for loss of vision following retinal detachment surgery.

Scleral Buckle for Retinal Detachment Repair

A scleral buckle is a common method to fix a detached retina.  In most cases, a band is passed around the circumference of the eye.  This is similar to donning a corset around your midsection, except in the case of the eye, the eye elongates.

The lengthening of the eye causes a change in your refraction, or, the strength of glasses needed to correct your vision.  A scleral buckle causes an increase in nearsightedness.

Other surgeons may elect to place a buckle on only a small portion of the eye, but the result is the same; a scleral buckle changes the refraction of the eye.

Swelling of the Retina

After surgery, some patients may experience swelling of the retina, termed “macular edema.” This can cause blurry or distorted vision. It can usually be treated with medication and resolves over time.

Cataract Formation

This is a very common cause of decreased vision after successful retinal detachment surgery.  Intraocular gas is often injected into the eye to help repair the detached retina.  While the gas is very helpful in reattaching the retina, it is not so good for the natural lens and hastens the development of a cataract.

Macular Damage

The macula, which is the central part of the retina, is responsible for sharp, detailed vision. If the macula has been damaged during the retinal detachment or the surgery to repair it, the patient may experience permanent loss of central vision.

Epiretinal Membrane Formation

An epiretinal membrane can form on the surface of the retina and cause decreased vision and/or distortion.  These are also called “macular pucker” or “cellophane maculopathy.”  While these membranes may form in eyes that never had a retinal detachment, they are commonly associated with retinal detachments.

Recurrent Retinal Detachment

Of course, it is also possible that the retina simply came off again.  This may be due to additional retinal tears or to a disease termed “proliferative vitreoretinopathy” or PVR, which is a condition where scar tissue forms on the retina causing it to detach or become distorted.

What Does This Mean? Retinal surgeons are usually pretty successful at reattaching a retina.  The whole process of recovery; however, can extend months beyond the actual surgery date.  None of the causes listed above can be self diagnosed and it is imperative you stay close to your doctor, preferably the retinal surgeon.

Contrary to what you may believe, retinal detachment surgery often, not always, leads to improved vision.  Thus, decreased vision after surgery should be evaluated by your doctor.

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Retinal Detachments Treatments

Vitrectomy Surgery for Retinal Detachments

Vitrectomy eye surgery for repair of a retinal detachment can be an alternative or adjunct to scleral buckle.  Vitrectomy surgery involves the removal of the vitreous from the eye.  This procedure was introduced (i.e. invented) in the mid-1970’s and enhanced our ability to treat retinal detachments.

Retinal Tears Cause Retinal Detachments

Remember that the culprit in “rhegmatogenous” retinal detachments is the formation of a hole or retinal tear in the retina.  The vitreous can exert “pulling,” or traction, on the retina and cause a retinal tear. 

Using a scleral buckle surgery, we introduced “slack” in the vitreous to release some of the traction.

Vitrectomy surgery, too, is focused (no pun intended) on relieving stress in the vitreous.  By cutting and removing the vitreous, the vitreous can no longer “pull” on the retina and cause additional tears and keep the detached retina elevated.

Remove the Vitreous, Replace with Gas

After removing the vitreous, the next step usually involves exchanging the vitreous and fluid with intraocular gas.  The purpose of the gas is to stop the migration of fluid to the space underneath the retina (by definition, a retinal detachment). 

Many people are told (incorrectly) that the purpose of the gas is to “push” the retina back into position, but this is not so.  The surface tension of the gas bubble actually acts as a cork, stopping migration of fluid from the vitreous cavity to the subretinal space.

A Vitrectomy Can Fix a Retinal Detachment
A Vitrectomy to Repair Retinal Detachment

In this way, the retina is reattached, and kept attached, until significant scarring takes place to keep the retina attached by itself.

The gas will absorb, but the length of time required depends upon the type and concentration of the gas (I use 16% SF6, sulfahexafluoride).  It does not stay in the eye as long as the gas others use as I believe this to minimize the amount of post-operative complications.

During the time gas is actually in the eye, patients are warned against experiencing large changes in atmospheric pressure.  Going to the mountains or airplane travel is usually prohibited as the decreased atmospheric pressure can cause a rapid increase in the volume of the intraocular gas.  This could cause the pressure in the eye to increase too fast.

In short, the gas is used as a tool to help reattach the retina.  Depending upon the location of the tear in the retina, a patient may be required to keep his/her head in a certain position following surgery.  This positioning is as crucial as the operation itself. 

For instance, if the tear is located at the top of the eye, the patient may need to sit up in a chair for days following surgery.  If the thear is located at the bottom of the retina, face-down positioning may be needed.

Advantages of Vitrectomy

There are a few advantages to vitrectomy for repair of a retinal detachment.  There is no worry about becoming more near-sighted as there is no scleral buckle placed.  Similarly, there is no chance of causing double vision as there is no manipulation of the eye muscles as in the case of a scleral buckle.

Basically, for the patient, there is less operating outside the eye.  Discomfort (“doctor-speak” for pain) is minimized.

There is, however, the chance of infection, as there is with any intraocular surgery, that can lead to blindness.  “Endophthalmitis,” the fancy clinical term for this type of infection, is less common in retinal surgery than cataract surgery.  The chance of infection occurring is small, somewhere around 1:5,000-10,000.

Vitrectomy with Scleral Buckle

Many times both a scleral buckle and a vitrectomy are utilized for a retinal detachment.  There are no clearcut reasons when to use vitrectomy or scleral buckle or both.  As I said last post, placing a scleral buckle can be time consuming in certain instances…thus affecting the decision.

What Does This Mean?  There are several ways to fix a retinal detachment.  Vitrectomy surgery fixes the retinal detachment from the inside, requires less tissue manipulation (i.e. operating) and is more comfortable than a scleral buckle. 

Using both modalities, in the right situation, can lead to a higher success rate as we are fixing a retinal detachment from both the inside (vitrectomy) and the outside of the eye (scleral buckle).

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Retinal Detachments Treatments

Scleral Buckle Surgery for Retinal Detachment

A scleral buckle is one of several ways to “fix” a retinal detachment. Other ways include vitrectomy eye surgery as well as a combination of scleral buckle and vitrectomy.  An office procedure, called pneumatic retinopexy, is sometimes used as well.

Scleral Buckles are “Oldies But Goodies”

The scleral buckle has been employed for about 75 years.  The principle behind a scleral buckle is to cause the shell of the eye, or sclera (the white “wall” of the eyeball) to indent, or “buckle.”  The most common way to achieve “buckling” is by oversewing a thick piece of silicone rubber or sponge around the eye or encircling the eye with a silicone band and pulling it tight (same as a belt “buckle”).

The longevity of the scleral buckle implies, at least to me, that it is inherently very good surgery.  It corrects the principal problem – relieving “pulling” on the retina.

A Scleral Buckle is Placed to Repair a Retinal Detachment
The Scleral Buckle Reduces the Diameter of the Eye (Yellow Arrows)

Pretend You Are Sitting inside Your Eye

The result of any scleral buckle  is to reduce the internal diameter of the eye.  In doing so, the vitreous can no longer pull on the retina.  The cause of a retinal detachment is a retinal tear (or retinal hole).

For example, suppose the room in which you are sitting is the eye and you are the vitreous.  The wallpaper of the room is the retina.  Stretch your arms apart and pretend you can reach from one wall to the other.  Your fingertips are glued to the wallpaper.  This is how the vitreous adheres to the retina.

If you move to the left, your right arm now pulls on the wallpaper (or the retina) and you cause a tear on the right side.  Similarly, if you move to the right, you create pulling, or traction, on the left wall and cause a tear.

By placing a scleral buckle around the eye, the internal diameter is reduced.  This would be the same as moving the walls of the room closer and, as a result, your arms would bend and create slack in the “vitreous.”  You could move left or right with less pulling on the wallpaper, and less likely to cause a retinal tear.

Same with the retina!

“Side Effects” of a Scleral Buckle

Side effects, or possible complications, of scleral buckle surgery include;

  • increased myopia (you will be more nearsighted) – due to the increased length of the eye.  There may also be a large change in the refraction due to astigmatism.
  • double vision – uncommon, but the buckle is placed outside of the eye and underneath the eye muscles.  By manipulating the eye muscles, double vision is possible.
  • pain – usually not an issue and is usually (in my experience) amenable to Tylenol/Advil.

Fun Facts About Scleral Buckles

  1. The eye is not taken out.  We wouldn’t be able to put it back in.
  2. The “buckle” is usually made of silicone rubber (different than silicone oil) and has no known systemic side effects.  It can also be made of a silicone sponge material.  These, too, are safe.
  3. The “buckle” is intended to be permanent.  At times, it may extrude, but it is very uncommon.  The buckle only really needs to be in place for a couple of months, but we usually never plan on removing them.
  4. Some surgeons use metal clips to help fasten the buckle around the eye.  This can be a problem if future MRI’s are needed.

What Does This Mean?

Though “old,” scleral buckles are not obsolete.

There has been a shift in practice patterns among retina surgeons over the past 15 years.  About 15 – 20 years ago, pneumatic retinopexy was first described (aka invented).  Scleral buckles with vitrectomy became popular in certain areas of the country and, more recently, vitrectomy alone has  become popular.

As I’ll explain in the next few posts, vitrectomy surgery has become instrumental for the repair of retinal detachment, but there is still a role for scleral buckling.

I believe it to be a very valuable tool for retinal detachment surgery, but their use is sometimes based upon the length of time a surgeon takes to perform that part of the operation.  It can take a matter of minutes…to hours.

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