Most ERMs do not get worse. Surgery should be consider when the distortion results in difficulties with daily activities related to sight in this eye.
Your question about ERM progression is controversial. I'm paraphrasing information posted on the website of Dr. Steve Charles of Memphis (try googling). Some doctors believe that ERMs continue to progress for months or even years. However Dr. Charles believes that an ERM stops progressing after about a month. (It was my personal experience that Dr. Charles is a marvelous retinal surgeon.)
There is a large body of evidence suggesting that early surgery has better results in terms of improved acuity and reduction of distortion. In addition, after some time (one researcher speculated about 18 months), damage from an ERM may be irreversible.
My doctor did not do any tests such as OCT. Just told me I had a "sheen" and was 20/20 and to come back in 4 months. The 20/20 was determined by an assistant by having me read the lines on the wall. No other tests were done.
Is this customary? Should other tests be done to establish a base-line.
I had the PVD and my left eye is very blurry including sometimes an opacity that prevents me from reading any of the lines. But, when everything is out of the way, my vision does seem clear.
I'm not an eye care professional. I've read that tests are not necessary to identify a macular pucker. (I suspect that it would show up in a Spectralis OCT image, but most doctors don't have access to this very expensive equipment.) I'd suggest that you download an Amsler grid and check the status of your affected eye on a regular basis. Having 20/20 vision and a macular pucker is certainly possible.
There are many patients with 20/20/ and a mild ERM. There are a number of test one can do. An OCT and a flouresceine angiogram. Most doctors would not want to burden the patient with additional costs. A four month wait is very reasonable.
Thank you for answering my follow-on questions. This is very helpful information.