29 CFR Part 1630, Regulations to Implement the Equal Employment Provisions of the ADA (Title I Regulations with amendments issued through May 2016)

(iii) The primary object of attention in cases brought under the ADA should be whether covered entities have complied with their obligations and whether discrimination has occurred, not whether an individual's impairment substantially limits a major life activity. Accordingly, the threshold issue of whether an impairment “substantially limits” a major life activity should not demand extensive analysis.