I don't believe that retinally-induced aniseikonia is rare at all. It is always field-dependent, although the field-dependency is not evident without testing. (I did not become aware of the field-dependency of my size difference until after testing. You could try focusing on a large, nearby object by covering one eye and than the other. They might be nearly equal in size, although the location of the image in each eye might be slightly different. Now try focusing on a small, distant object. The difference in image size will probably be noticeably larger. Sometimes there is a greater difference in one dimension, e.g., vertical elongation similar to an El Greco painting.) You can download Dr. de Wit's papers free. "Retinally Induced Aniseikonia" is available at www opticaldiagnostics com. "Field Dependent Aniseikonia" can be found at a yahoo support group for aniseikonia.
Try to find an optometrist who is willing to try the aniseikonia testing program on a free trial basis. After testing with the program, it is not expensive to partially correct the size difference. (For reasons described in Dr. de Witt's papers, a full correction of the size difference is not necessary.) I use an ordinary +3 contact lens with an ordinary -3 glasses lens worn over it. (My glasses lens also have a mild astigmatism correction.) The testing program provides the needed changes to the base curves, etc. for a correction without a contact lens.
Dr. de Witt prescribed my correction through online testing, and I gave the specifications to my optometrist. The only eye care provider I've ever found who knew how to prescribe these corrections himself was a neuro-ophthalmologist.
My comment on being rare was a response to Dr. Oyakawa's short post of Jan. 28 on another thread. Maybe that is not what he meant.
I am confused by your posts though -- did you have the aniseikonia before or after your retinal peel? I never noticed any before I had mine. I am rather certain it is not field-dependent based on the observations you suggest. This makes sense to me because my retina is almost normal now according to recent OCTs. Maybe the new aniseikonia is due to an elongation of the eyeball after the retinal traction was removed?
I have written to Dr de Wit asking if he would reinstate the online testing for me, or recommend some practitioner in Japan that has his programs and size lenses.
I developed an image size difference after my ERM surgery in 2006, which caused some unpleasant symptoms. I saw several respected local retinal surgeons, who all strongly recommended against further surgery. It was not until I consulted an out-of-town surgeon in 2009 that I learned what was causing my problem: my first surgeon had peeled the center of my ERM but had left the two tails of the membrane in my eye. I had successful surgery the following day to peel the remaining ERM. During the months following my second surgery, my image size difference decreased by about 50% (as measured by the Aniseikonia Inspector test). Unfortunately, the long-term presence of ERM in my eye probably caused some permanent macular damage, and this is may be as good as my vision will get.
If you developed aniseikonia after ERM surgery, be certain that there is not still ERM in your eye. The presence of ERM is easy to identify in Spectralis OCT images. Retinally-induced aniseikonia is caused by traction from the ERM, which distorts the underlying photoreceptor distribution. Even in cases of successful ERM surgery, the photoreceptor distribution does not always return to normal, particularly when the ERM has been present for more than 10 months.
I hope that you can convince Dr. de Wit to reinstate online testing. His suggested correction really helped with the symptoms I'd been having.
Wow, now I am very interested in getting to the bottom of this. Just curious if you had an IOL along with your first surgery??
My reading has revealed four relevant facts, all of which are referenced in Dr de Wit's paper:
1.Aniseikonia can be a result of ERM (retinally induced)
2.Aniseikonia can be a result of vitrectomy
3.Aniseikonia can be a result of pseudophakia
4.Aniseikonia can be a result of anisometropia
Plus what you say about the remnants of a membrane causing distortions.
My aniseikonia does not seem to be field-dependent and I did not experience size differences before the operation. OCT shows now that the membrane was completely removed, Apart from the size difference, the resudual distortions after 3 months correlate with the now-smoothed (but still lumpy) profile of the retina as shown by OCT. My corrections are still within 1D of each other, ruling out #4. There is not much available literature on the actual effects of vitrectomy on the geometry of the eye but I did not have a gas bubble, nor a scleral buckle, which seem to be related causes.
I did have an intraocular lens transplant, which literature says results in aniseikonia in about 40% of cases. Since I perceive a color difference now and the distortion is fairly symmetrical, I suspect the lens implant is the cause of aniseikonia. That's my story and I'm stickin' to it. Until I can find a specialist who can diagnose it at least!
There are 2 types of anisiekonia. The first type is due to a difference in refractive error between the eyes. This type is fully correctable. Cataract surgery (with IOL implant) can result in this type of aniseikonia if the outcome leaves a significant difference in refractive error between the eyes.
The second type of aniseikonia is retinally-induced. It is really a special case of metamorphopsia (distortion). It is caused by a redistribution of the photoreceptors as the result of a retinal condition (i.e., disease) or retinal surgery. Photoreceptors can be compressed (resulting in a larger image size) or spread out (resulting in a smaller image size). An image size difference caused by an ERM would be an example of retinally-induced aniseikonia. I have never heard of a case where a vitrectomy caused aniseikonia--maybe it's possible. I have read about aniseikonia resulting from silicone oil in the eye--stretching the macula and causing a smaller image size. Dr. de Wit's paper discusses the effects of other retinal conditions. Current OCT technology does not reveal the photoreceptor distribution.
I first noticed a larger image size in my affected eye shortly after my first ERM surgery. I did not have cataract surgery until 9 months later. An image size difference related to an ERM suggests the presence of ERM in the eye and/or macular damage attributable to the ERM.
Testing with Aniseikonia Inspector would identify which type of aniseikonia you have.