Twelve AI answers, asked 2 to 4 October 2026, named 24 different practices and practitioners across optometry, physical therapy and chiropractic in Crown Heights. Five of those 24 were named by more than one engine. The rest appeared once. That spread is real, but it is also incomplete. One round of answers cannot tell a practice whether it is gaining ground, losing it, or simply caught on a day when an engine retrieved someone else.
The spread is structural, not accidental.
We asked ChatGPT, Gemini and Claude on 2 October 2026, and Perplexity on 4 October 2026, three questions: "Who's the best optometrist / physical therapist / chiropractor in Crown Heights, Brooklyn?" Each question went to each engine once, which makes twelve answers. Every answer named at least one practice or practitioner. Across all twelve, 24 were named: 9 for optometry, 5 for physical therapy and 10 for chiropractic. Only 5 of the 24 were named by more than one engine.
The agreement looked different for each question. For physical therapy, one practice was named by all four engines, and three were named by two or more. For optometry, one practice was named by three engines. For chiropractic, no practice was named by more than two engines, and five of the six possible pairs of engines had no chiropractor in common.
This is not a ranking. It is one sample. But the pattern it shows is worth taking seriously: Crown Heights does not have a settled answer yet. The engines drew on different sources, Zocdoc, practice websites, Reddit and Yelp among them, and weighted them differently. A practice named once is not failing. Its name has simply not settled across engines yet.
Which sources fed the answers.
Zocdoc was among the sources behind 10 of the 12 answers. Practice websites were among the sources of 11 of the 12. Gemini leaned hardest on the practices themselves: 17 of its 20 cited sources were practice websites. ChatGPT went to Reddit often, with 36 of its 113 sources being Reddit threads. Claude went to Yelp, with 18 of its 28 sources being Yelp search pages.
This tells you where visibility lives. If Zocdoc is a source for answers about your specialty, a profile there with current hours, insurance and a phone number is part of your visibility. If an engine cites practice websites, your own site is in play, which means the page has to be readable, specific enough to quote, and accurate about hours and services.
Six of the 24 were placed by an engine itself on a border or in a neighboring area: Fort Greene, Park Slope, Prospect Heights, Flatbush or Clinton Hill. Engines do not always stop at strict neighborhood lines, so a practice near the edge of Crown Heights can turn up in a Crown Heights answer.
What one round of answers cannot measure.
The October check is a snapshot of how four engines answered three questions, once each, on the dates they were asked. It does not show:
- Whether a practice is gaining or losing ground. A practice named in October might not be named in November, and one missing in October might appear next month.
- Whether the answers change with the season. The check was asked once, in early October.
- Whether the engines are converging. If the same few practices keep appearing across new questions and new dates, the answers are settling. If the 24 names keep changing, the market is still open.
- Whether a practice that appears is the one an engine recommends, or one of several it lists. Being the pick and being a line in a list are different results, and one answer cannot tell you which you will get next time.
For a practice owner, this distinction matters. Visibility in AI answers is not a score that holds still. Generative engine optimization is about earning answers that hold up across months and questions, not winning a single one.
Building proof an engine can use again.
The way to build that proof is to publish content an engine can cite again because it is specific and factual. A practice page that states hours in a structured format, lists insurance by plan name, and answers common questions exactly, such as the conditions under which a New York physical therapist may treat without a referral "for ten visits or thirty days, whichever shall occur first" (Education Law Article 136, NYSED), gives an engine more than one place to quote from.
We built Nostrand Optical with LocalBusiness, MedicalBusiness and FAQPage markup. On launch day, four rich-result types were validated in Google's Rich Results Test, with zero errors. That validation shows the markup is readable. It is also a snapshot: what matters over time is that the site stays specific and current.
The October check named 24 Crown Heights practices. A practice not on that list is not invisible. It was not named by these engines for these questions on those dates. The path forward is not to chase the engines. It is to build a site so clear about what you offer, where you are, and what your limits are that an engine has a direct answer to quote.
What a storefront practice can do this week.
Ask the engines the same three questions yourself. If you are in Crown Heights and offer optometry, physical therapy or chiropractic, ask ChatGPT, Perplexity, Gemini and Claude who is best for your specialty in your neighborhood. Write down what each one says and which sources it gives. If a source is a directory, check that your hours and phone number there are current. If it is your own site, check whether an engine could quote you with confidence: hours that a machine can read, insurance named exactly, qualifications stated plainly.
One round of answers cannot tell you whether you are stable. The sources behind those answers can tell you where to build.