Dark energy is constantly pulling all objects away from each other with increasing speed. This in turn causes a red-shift of the light from the most distant object where this effect is most profound. This red-shift will gradually increase as the objects move away faster. Is there going to be a time where the objects travelling away will emit light of such long wavelength that they will ddisappear from sight?
In an acceleratingly expanding universe, there will be an emission time of light from a distant galaxy after which we can never recieve newly emitted light.
Old light will eternally be received, but even more dimmer and red shifted.
See The Long–Term Future of Extragalactic Astronomy for more information.