For whatever reason it seems that the Thaivisa search engine isn't indexing anything other than very recent search content. For example, I looked up "TM30" in this forum which is is hot topic and only returned 17 hits going back no further than Aug 12th. If anyone feels so inclined I'd suggest someone contacting Thaivisa tech support as that is sort of a bug in the operations of the site, well, unless for some reason it's intentional.
The other way to skin a cat is to use an external search engines like Google and limit the search to the "thaivisa.com" domain and look for "cataract" and "Chiang Mai" as search terms. This is what you get. Paste the links into your browser:
Also, if you're cost conscious check into the eye clinic at Maharaj. Sripat and Maharaj share buildings and doctors within the same complex. Sripat will charge you private hospital prices for they same surgery that can be done a Maharaj. Same surgery, probably the same doctors using the same operating rooms. The cost at Maharaj is time. You'll spend 4 or 5 hours getting your consultations. But if you save 15 to 30k THB per eye as opposed to using a private clinic like Sripat or RAM - well, what your time worth? My two cents worth.