You Look All Bent Out of Shape

Distortion, also known as metamorphopsia, is a symptom of many macular diseases.   Anything that affects the macula can cause distortion; epiretinal membranes, macular holes, macular edema, diabetic retinopathy and macular degeneration.  The macula is a place in the retina, the functional center.  Thus, the term “macular” becomes an adjective when describing retinal disease located in the center of the retina.

OCT scan of a retina at 800nm with an axial re...

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The macula is a small area of the retina measuring about 1.5 x 1.5 mm.  It is very sensitive and allows us our best color vision and the ability to see 20/20.  A normal macula (fovea) is smooth and slightly concave (see OCT).  Light falls on the normal macula giving us vision.  This is very similar to a projector focusing images onto a movie screen.  If there is a physical change to the macula or disease, central vision is usually affected.

Macular Pucker or Epiretinal Membranes

Epiretinal membranes are, as the name implies, membranes that develop on the surface of the retina and cause the underlying retina to wrinkle, or “pucker.”  This physical wrinkling of the macula causes decreased vision and distortion.

Surgically removing the membrane usually improves the distortion and can improve the vision, too.

Macular Holes

If you were to poke a pin through a piece of ballon and then stretch out the rubber, you’d create a nice round hole.  A macular hole is actually a stretch hole in the center of the macula.  Images that fall within this hole are not seen as there literally is no retina in the center of the macula.

Symptoms include decreased vision, distortion and sometimes, scotomas, which are the fancy name for blindspots.

Macular Edema

Swelling of the macula can occur from a variety of causes.  The two most common causes germaine to this web site are diabetic retinopathy (more specificially, diabetic macular edema) and swelling secondary to choroidal neovascularization in cases of wet macular degeneration.

Other causes, however, include central serous retinopathy, central and branch vein occlusions, cystoid macular edema from cataract surgery (uncommon these days) and from cases of intraocular inflammation (aka uveitis).

Macular Degeneration Causes Distortion 3 Different Ways

As above, choroidal neovascularization can physically distort the retina and cause distortion.  These abnormal blood vessels can develop in between the layers of the retina causing physical disruption of the retina.  The analogy here is exactly like the “Princess and the Pea.”

Wet macular degeneration can also cause macular edema as we discussed above.

Dry macular degeneration can also cause symptoms of distortion.  One of the layers of the retina, called the RPE, becomes diseased and degenerates.  This loss of one of the principle layers of the retina can cause distortion.

What Does This Mean? Distortion, or metamorphopsia, can be a symptom of a variety of retinal or macular disorders, not just macular degeneration.  The key for saving your sight is early detection and diagnosis.  Usually this may require consultation with a retina specialist to discuss the various treatments.

A fluorescein angiogram and/or an OCT (Optical Coherence Tomography) may be very helpful to your doctor, but this can vary.

Other causes of metamorphopsia, not related to the retina, could include large amounts of astigmatism or a decentered lens.

While most causes are indeed retina related, it is also important to note that most have a treatment with the exception of dry macular degeneration.  There is some rumbling; however, that there may be some promising treatments for dry macular degeneration in the near future.

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Comments

  1. Your website explained a lot. I have vision distortion + blindspots on one eye that might be caused by macular pucker membrane and/or macular edema. I am going to have vitrectomy within a few weeks. But epiretinal membrane removal has not been considered sofar, because the doctor is not sure. I would like to have a second opinion from Dr. Randall Wong. I live in Fairfax county and am ready to come to visit Dr. Wong. Please give me a response.

    Thanks.
    Bernard Souw

  2. Dr. Souw,

    Please feel free to call and make an appointment, or, please feel free to email your contact information to me and we’ll set up an appointment for you.

    Look forward to meeting you and thank you.

    Randy
    RWong@RetinaEyeDoctor.com

  3. My son had an episode of central serous retinopathy on one eye several years ago. His vision has improved but never got back to normal. Is there any treatment that would help at this point. He is 24 and has seen several retina specialists and one suggested some form of laser treatment.

  4. Dear laztraz,

    Hard to say without examination. There is hope if there is still fluid underneath the retina…if you can determine.

    Randy

  5. Randy,
    Thanks for responding. I was not sure what you meant when you said there is still hope if there is fluid under the retina…

    laztraz

  6. Dear Laztraz,

    I meant it to mean if there is residual fluid or macular edema….then there is room for improvement.

    r

  7. Kirk Moffitt says:

    I have visual distortion in one eye where the center of my visual field is elevated by about 1/6 degree, creating vertical diplopia. Acuity in this eye is poor, at about 20/100. I had a vitrectomy and membranectomy 6 months ago and then another membranectomy 1 month ago. I have seen no real improvement in distortion or acuity. My doctor says there is a lot of variability in the time to heal. What should I be expecting? Also, am I correct in thinking that if my acuity were much better it would really interfere with my vision because I would have two in-focus images in competition.?

  8. Dear Kirk,

    Hmmmm.

    When an ERM is removed and the initial (pre-surgery) vision is poor, vision may improve slowly for six months. I usually follow these types of patients with an OCT or even a fluorescein to monitor the macular edema caused by the ERM.

    If this may be your situation, I’d ask your doctor about residual macular edema.

    With regard to the double vision, I simply can’t tell without examining you, but you may indeed be correct (sorry for the non-answer.).

    r

  9. frank williams says:

    I have recently been diagnosed having an epimacular membrane causing distortion and lack of color saturation in one eye and surgery has been recommended by an eye specialist. What I have noticed is that no one offers a reason for this except ‘that it is age related’.However, I know a lady in her mid eighties that still has 20/20 vision and according to the maxim that the exception proves the rule this means that there are other causes. It is much better to find the cause and deal with it don;t you think? Have you ever endeavoured to find the causes?

  10. Dear Frank,

    It is my belief that an ERM will form in those with the genetic pre-disposition to form such membranes.

    There is no reason why a healthy eye doesn’t see 20/20 for the entire life!

    Randy

    Randall V. Wong, M.D.
    Retina Specialist
    Fairfax, Virginia
    http://www.RetinaEyeDoctor.com

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