More light is better most of the time, but it is crucial for patients with vision loss. More light is better for two reasons. One advantage is you see more contrast on whatever you are looking at. This enhances the contrast between dark and light edges. Thus, you can see the image better, even if it is magnified. Additionally, when you have more light, your pupils shrink as well, depending on what you're looking at. People always feel like they can see much better outside in the daylight. It happens because your pupils become smaller, and your natural range of focus increases. Therefore, having extra light has a double-sided advantage. There are some instances where lighting, or at least more lighting, does not work. In most cases though, the added light does help to increase the contrast and visibility.
With so many options of lighting available it is really important to speak with a low vision optometrist who has experience with guiding a patient with vision loss on the important aspects of lighting.
One thing that is important is to identify for the patient the places where lightning will have the most impact. For example, is the patient struggling with reading? In which case an adjustable floor lamp next to their favorite reading chair is the answer. However if the patient is struggling with mobility and bumping into things then the overall level of home lighting may need improvement.
It is important to understand that not all lighting provides a low vision patient with the same improvements to color contrast. When looking for lighting it is recommended to find a light that is full spectrum or has color rendering index (CRI) of over 90. This will improve the quality of color that the light reflects.
With so many different options to choose from it can be hard to know if you should get fluorescent, LED, Halogen, or incandescent. A low vision optometrist can guide you on the best lighting for your needs. For example LED is more adaptable with various form factors, adjustable strengths, high CRI, and less heat generation.