"Rights of light" are a form of negative easement which may, for example, be acquired by and attached to any specific windows or openings that allow light to enter a property. In some countries, owners of buildings with windows receiving natural light may establish a "right to light", which traditionally would grant the property owner the right to unobstructed access to light entering the property.
Thus, "right(s) to light" has meaning significantly different from "right(s) of light", though both are correct. The most common usages seem to include "right(s) to light disputes" or "right(s) to light cases" and "right to light law". Far less common are "rights to light law" and "right to light laws".
The property owner's need and use of light, as well as the length of time the owner has used any particular light, might all be essential criteria for ascertaining the material grounds of complaints against parties engaging in construction (often a neighboring building) or other obstruction which might block one's light. Thus is established the owner's 'right to light'.
For interpretations of technical details and definitions in right to light cases, courts often call on expert witnesses, such as surveyors ('right to light surveyors' or 'surveyors of light'), architects and other scientists, since even the most basic definitions of commonplace words might be under dispute and must be clarified. This fundamentally scientific approach is necessary in right to light disputes because material facts often must be discerned and evaluated by material means, such as empirical/objective investigation and measurements.
(Some examples of technical & scientific principles involved in modern right to light cases, and their role in modern interpretations of relevant laws/doctrines, are discussed in "A Review of Current Practice".