Hi Greg,
Thanks for your kind words. The level and number of reviews we have gotten has played a big role in our schedule. For new patients, I am booked out about 2 months, and for former patients, between 4-6 weeks (we hold more appointment slots for former ["loyal"] patients). Our on-line reviews have helped with our SEO and high listing when people do a search. This is why getting reviews in both quantity and quality is so helpful.
It is very hard to "ask for the business." I have three thoughts that your could consider as a starting point. First, I have no doubt that many patients say nice things to you at the end of the exam. You can piggyback off of that to thank them for their feedback, and let them know that one of the primary ways people find you is through on-line reviews, and that if this patient can take a moment to write a review with the comments just stated, others will be more likely to find you as well. If you do something different (the proverbial "no one has figured that out before"), it provides an opportunity so that other people who may have struggled with similar issues can read in an on-line review that they could get help as well. This could be someone who was told in the past that they couldn't wear contact lenses, or someone with a chronic complaint that was never addressed, a child who passes screenings but has other vision problems never diagnosed, etc.).
Secondly, your front office staff often gets positive feedback when the patient goes to check out. If the patient says something positive, the staff member, if you feel uncomfortable doing so, can ask for the review, similarly by saying that this is how nice people like you find us. Also, if someone is particularly nice, your front office staff can ask for reviews by saying "can you refer more patients like you, please?" If a patient isn't a frequent on-line reviewer, you can have printed form with instructions to give to the patient as to how to post a review. (You can explain to patients that you have taken the time to get these printed up because the questions comes up frequently enough).
Thirdly, there are recall/patient management software programs that help with recalls, reminders, and ALSO will request reviews for patients who fill out brief surveys about their experience. These programs will then transfer the patient to Yelp, Google, etc.
I hope these ideas help. Most of us are uncomfortable "asking for business (even though we hear it from our many reps virtually every time they visit)." Either work on verbiage that you may be comfortable with, or consider one of these other options. Please let me know how it goes, if this information is helpful, and if you want to discuss this further.
Good luck!