Can the old dropped lens “cobra head” fixtures be retrofitted with flat lens glass to make them a suitable full cutoff fixture?
No. In addition to replacing the dropped lens or refractor of the fixture, the reflector inside the fixture must also be replaced to properly distribute the light spread from the fixture down onto the road. Since the new flat lens fixture is relatively inexpensive compared to the cost of performing this type of customization, it is more cost-effective to replace the old fixture with a new flat lens fixture of the correct photometry.
