Reading Glasses

Reading Glasses

The link between “near work” (such as reading and writing) and myopia has been extensively studied in the recent years ([54]; short summary in ), and there is little doubt that the correlation is, on average, highly significant. Although it is not clear what exactly the critical visual experience is, a current hypothesis is that reading imposes a slight defocus to the retina because subjects accommodate too little. In fact, most studies have found a “lag of accommodation” of around half a diopter at a 3-D reading distance [60].

             The lag of accommodation places the focal plane behind the retina and could have a similar effect on eye growth as wearing a negative lens. Inspired by this idea, a number of studies have been conducted with reading glasses in children since they should reduce the lag. The first major study from Hong Kong [29] showed a clear beneficial effect of progressive addition lenses with +1.5 or +2.0 D addition, which reduced progression to about half of the progression with single vision lenses (–1.2 D in 2 years). The idea was also tested in a larger multicentric study in the United States, the Correction Of Myopia Evaluation Trial (COMET). This study also showed some beneficial effect of progressive addition lenses (on average, 14% inhibition of the progression with single vision lenses of about 1 D in 2 years [16]). The authors considered the inhibitory effect as “clinically not significant”. However, if the children were clustered according to their lag of accommodation and phorias, the inhibition could rise to almost 60% in those children who were esophoric, had a large lag of accommodation (>0.43 D) and had less myopia at the beginning of the treatment (>–2.25 D) [17].

          It is important also to recognize that the effects of the progressive addition lenses were generally more expressed when myopia was still low. A third major study from Hong Kong (the Hong Kong Lens Myopia Control Study [9]) found only a trend of a beneficial effect of progressive addition lenses, but the effect appeared significant when only children with low myopia were considered. Reference on Medicinal plants Part I Reference on Ayurveda treatments, Principles, Yoga and Health Articles Reference on Indian medicinal plants and its treatments.