The Effect of Different Working Distances on the Accomodative Response

Background: The accommodative response is an important tool that is helpful in the diagnosis of a variety of binocular vision disorders. By a patient’s accommodative response, it can be determined if the patient is over-accommodating or under-accommodating. Monocular Estimation Method (MEM) and Nott retinoscopy are two common techniques that are used in a clinical setting to quantify the accommodative response. These techniques are clinically done at a setting of 40 centimeters, however most patients will hold their reading materials or near work at a distance closer or farther away than 40 centimeters. This project built upon previous work and further explored how varying working distances affect accommodative lag.
Methods: This study used Nott retinoscopy method, and MEM for estimating the accommodative response. Nott retinoscopy requires a near point rod, a retinoscope and a Snellen near target; while MEM requires a retinoscope with a near card attachment, and a set of -1.00 to +1.00 diopter (D) loose lenses in 0.25D steps. The subjects in this study ranged from 20-30 year old healthy optometry students who have vision that is 20/40 or better and a normal binocular vision system. Visual acuity was taken on eye of each participant as well as a gross examination for any heterotropias. Participants in the study were asked to wear their best spectacle correction when tested. Nott retinoscopy and MEM retinoscopy were each performed on each participant’s right eye at three different test distances: 25 cm, 40 cm, and 50 cm. Each test was performed monocularly, meaning only the participant’s right eye response was taken into consideration. The accommodative response for each test distance for each method was compiled into a Microsoft Excel document and analyzed. After testing was complete, the accommodative response at each testing distance was compared using statistical data analysis.