\[\frac{\sqrt{8 + \sqrt{10}}}{\sqrt{8 - \sqrt{10}}} + \frac{\sqrt{8 - \sqrt{10}}}{\sqrt{8 + \sqrt{10}}} =\]
\[= \frac{\left( \sqrt{8 + \sqrt{10}} \right)^{2} + \left( \sqrt{8 - \sqrt{10}} \right)^{2}}{\left( \sqrt{8 - \sqrt{10}} \right)\left( \sqrt{8 + \sqrt{10}} \right)} =\]
\[= \frac{8 + \sqrt{10} + 8 - \sqrt{10}}{\sqrt{8^{2} - \left( \sqrt{10} \right)^{2}}} = \frac{16}{\sqrt{54}} =\]
\[= \frac{16\sqrt{54}}{54} = \frac{8\sqrt{54}}{27}.\]