Library catalogs and article databases (such as PubMed and Google Scholar) allow you to save searches and create "alerts." You will thus receive notification when citations, books, etc. that meet your search criteria are added to the database.
Creating Alerts: PubMed (Instructions and 1.5 minute video).
How to sign up for email alerts in Google Scholar.
In addition, most journals allow you to receive electronic tables of contents ("eTOCs") as new issues come out, or as new articles are posted to their web site.
Keep in mind that once you are not affiliated with UC Berkeley, you will not be able to access the full text of every article from these journal tables of contents unless the article is open access or otherwise freely provided from the publisher.
Alerts and eTOCs may be set up for delivery via email or RSS feed.
Here is a list of Optometry, Ophthalmology, and Optics journals from the National Library of Medicine, NIH. You may use this to help you set up delivery of electronic tables of contents. Please note this list includes journals that are no longer publishing.
In the database search results, click the button to check for an online copy of the article.
Or, search by article title in UC Library Search; if it is available online, there will be a link to access it.
It can be helpful to identify articles that cite your key references. There are a number of databases that can help with this. Start with Scopus, Web of Science, or Google Scholar. The more specialized databases may provide additional citing references.