Dynamic Interactions of Eye and Head Movements When Reading with Single-Vision and Progressive Lenses in a Simulated Computer-Based Environment

Abstract

Eye movement and head movement strategies and timing were contingent on viewing conditions. The longer eye movement duration and gaze-stabilization times suggested that additional eye movements were needed to locate the clear-vision zone and commence reading after the RSS. Head movements with PALs for the SP condition were similarly optically induced. These eye movement and head movement results may contribute to the reduced reading rate and related symptoms reported by some PAL wearers. The dynamic interactions of eye movements and head movements during reading with the PALs appear to be a sensitive indicator of the effect of lens optical design parameters on overall reading performance, because the movements can discriminate between SVL and PAL designs and at times even between PALs.

Comparison of progressive addition lenses for general purpose and for computer vision: an office field study

“…The blurred and distorted vision through the peripheral and lower parts of the lens can affect the perception of steps and may lead to more variable foot positioning and an even higher risk of falling . Furthermore, eye movements as well as gaze stabilisation take longer, while the wearer needs to find the area with the optimal focus for a given viewing distance during near and intermediate tasks . A narrow progressive zone may lead to larger horizontal head movements, when reading a line of text at near or intermediate distances; thus, the co‐ordination of eye and head movements is affected .…”

“…Laboratory studies with controlled viewing conditions are useful to describe the optical and physiological mechanisms involved in presbyopic corrections. In addition, field studies are required to investigate the effects of lenses over a full working day in real office conditions to identify the possible implications on the subjective ratings of the viewing conditions, visual or musculoskeletal strain and ergonomic conditions.…”

How to place the computer monitor: measurements of vertical zones of clear vision with presbyopic corrections

“…The present results suggest that general purpose PALs can provide comfortable and clear vision in the vertical direction on a monitor that is placed sufficiently low and inclined backward and at the correct distance; however, the suitability of general purpose PALs for computer work may also depend on the horizontal field of clear view, which is limited by the progressive zone. The limited horizontal width of clear vision affects the patterns of the co‐ordination of eye and head movements when reading pages of text . Furthermore, the performance in the occupational task may be impaired.…”

“…The first limitation refers to the horizontal direction: clear vision for intermediate and near vision is only possible within a central vertical progressive zone, while astigmatic distortions are present in the left and right peripheral visual fields. As a consequence, the patterns of horizontal eye and head movements are modified . The second limitation of PALs refers to the vertical direction and is the topic of the present study, namely, to use the required addition for a given viewing distance, the inclination of the eye and the head must be adjusted, so that the visual line intersects the lens at the point with the required near vision addition.…”

Adaptation to Progressive Additive Lenses: Potential Factors to Consider

“…However, some presbyopes have difficulty when wearing PALs and may experience moderate to severe visual symptoms such as blurred vision, headaches, perceived movement of the peripheral visual field or “swim”, balance issues, and nausea 18 . Eventually, these individuals discard PALs and use other corrective modalities such as reading glasses.…”