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. Author manuscript; available in PMC: 2017 Jul 17.
Published in final edited form as: Ophthalmology. 2016 Apr 16;123(7):1458–1468. doi: 10.1016/j.ophtha.2016.03.006

Figure 2. Final design of the Ocular Pain Assessment Survey (OPAS) following factor analysis and validation studies.

Figure 2

The boxed regions represent the gold standard method of quantifying pain intensity (Wong-Baker FACES Pain Rating Scale) against which the test numerical rating scales were validated, and the 6 factors (dimensions) of the OPAS comprising of test sub-scales that loaded onto each of the factors. Scores for each of the sub-scales were then followed as mean composite scores for each of the 6 factors, and monitored individually over time, generating both holistic and nuanced information. Symptomatic relief (Qs. 27 and 28) did not load onto any factors but was retained based on the physicians’ agreement that it formed an important question, which could be analyzed separately if needed.