Date of Award
Master of Science in Vision Science
Negative Relative Accommodation (NRA) is a common subjective protocol used by many practitioners to assess a patient's ability to reduce accommodation relative to a nearpoint vergence demand of 40 centimeters. High Neutral retinoscopy (HN) is an objective test that utilizes a similar procedural protocol and vergence demand, also to assess a patient's ability to relax accommodation. During HN, excessive plus power is slowly decreased so that the patient must reduce accommodation in order to clear letters at a nearpoint distance of 50 centimeters. For reasons including examiner preference, difficulty of testing, confidence with endpoints or patient cooperation, HN is not a commonly utilized test. Although both NRA and HN assess how well a patient can "actively" release accommodation, HN requires the patient to clearly locate and identify letters alphabetically during the examination, adding a cognitive component. As a result, HN provides more of a "real life" (and arguably more practical) assessment of accommodative relaxation than NRA, and can provide valuable information in instances when a patient presents with problems that may be related to hyper-responsive accommodative. The purpose of this study is to determine if NRA recovery can confidently substitute for High Neutral retinoscopy when HN results are desired. Statistical analysis reveals an insignificant correlation between the net values of predicted versus actual HN net values (R=~ 0 .184) as determined by the equation -0.004076 1 (NRA recovery net) + 1.600883 15. From a clinical perspective, the errors of predicted HN to true HN results was within 0.37 diopters if specific clinical features were ruled out. The results of this study suggest that an examiner may elect to use a predicted HN net value based on the NRA recovery net value when only an approximation is desired, and only when latent hyperopia and a tendency for an accommodative lead under binocular conditions has been first ruled out.
Chhim, Yousim and Chau, Nhi, "Investigating the relationship between negative relative accommodation recovery and high neutral retinoscopy" (2006). College of Optometry. 1558.