If we assume their homeworld is similar to Titan, but instead orbiting a Neptune sized gas giant and a bit bigger and receiving the same amount of Solar energy as Titan, The star is a main sequence G type star, and the moon has a surface gravity of 0.28 G's. The atmosphere isn't smoggy like Titan so more light reaches the surface. What wavelengths are they likely to see in? If they came to Earth and observed the planet would they be able to see it like Humans do? Also would it be possible for them to have eyes that resemble some of Earth's species?
The amount of light will be 0.0178 of the light received by the Earth. Less than 2%. If vision is in the optical range, their eyes will have to maximize their light catching capacity. Basically they will be very big. Visiting Earth would be blindingly bright for big eyed aliens.
However, there is an alternative vision scheme. This was proposed earlier for another answer, but it certainly fits here.
This article by Robert Freitas called "Extraterrestrial Zoology", originally published in Analog, July 1981, has an interesting discussion of alien senses.
Vision, of course, is simply the detection of one narrow set of wavelengths of light within the entire electromagnetic spectrum. One alternative to “visual” sight is infrared (IR) vision, or seeing with heat waves. The rattlesnake is quite good at this – the creature has two imaging eyeballs operating in the visible, and two conical pits on either side of the head which permit binocular IR sensing of temperature differences as little as 0.002 °C. The theory of optics predicts that alien infrared eyeballs with resolution close to that of the human eye could have apertures as small as 4 centimeters at 93,000 Angstroms (the peak wavelength of black body radiation emitted by a warm human body). This compares well with the size of the eye of the Indian elephant (4.1 cm), the horse (5 cm), the blue whale (14.5 cm), and the largest cephalopods (up to 37 cm).
The fact that rattlesnake have binocular IR sensing and that optics can allow for IR eyes having the same resolution as the human eye, then alien organisms living on a low light planet would be able to see quite well if they evolved infrared eyesight. The ability to see such remarkably small heat differences means excellent vision even on a cold planet. Visiting Earth would be blindingly bright for infrared eyed aliens too.
Aliens with infrared eyesight would look grotesque. There would be large holes in their heads where we have eyes.