Firstly - it is not always about spending a fortune on marketing and advertising. It is more about laws of physics than math. If you can put enough force into things that all increase the energy of that force - meaning, doing less isolated efforts of marketing but more integrated approach. Look ...
The steps are the easy part. It's the execution. You can put together a great lead gen machine using content, cookies, and email marketing.
Betalist and similar startup "launch" sites house a pretty updated list of software-based products that are being built. Betalist in particular is for beta level software projects, so at the point when they'd be looking for these types of solutions.
I recommend using a cold emailing marketing solution like mailshake, woodpecker, etc.
There are two steps. First, plot the addresses of the stores that carry your product (https://www.mapcustomizer.com/) Second, find optometrists near there (Yelp, Google, LinkedIn Advanced Search) In all honesty, it probably took you longer to write the question than it would to find what you're...
Central CRM in the cloud that everyone has access to. Infusionsoft might be a good solution. Obviously you need email follow up series integration and sales funnel automation.