The HD Clear UV glass filter is a good alternative to the standard clear filter.
This filter looks just like a clear filter but also provides some additional protection against harmful UV light below 410Nm. It is worth purchasing this filter rather than a standard clear as the additional cost is minimal.
For more advanced absorption of different levels of UV light, specialized UV filters are available. These are designed to eliminate atmospheric haze caused by the scattering of ultraviolet and blue radiation.