Tony,
In a nutshell, I'd say the great benefit of a group practice is the ability to share cost-- equipment, salary, office overhead etc.... Also the group practice may have more clout, allowing for volume buying power(contact lenses and glasses).
A group practice can also be beneficial because it can incorporate doctors with different interests and skills such a one doing vision therapy, another doing speciality contact lenses, another doing pediatrics, etc.........
The drawback is that you have "two or more" bosses. Decisions have to be shared. Equipment buying decisions and hiring decisions among the most important.
All the docs in a group need to be similar in thinking. A cheap-skate doctor (and there are many such OD's) would be difficult to work with if you are into buying and practicing with "state-of-the-art" equipment.
Group practices will probably increase in number in the future (for the reasons mentioned above).
