Abstract
Purpose: :
We have described a novel, short, and safe accommodation training to induce a pupillary constriction during far accommodation in myopic school-aged children resulting with great improvement of their visual acuity. In this paper we clarify whether the method to keep the object’s retinal projection size constant is essential for induction of a pupillary constriction during far accommodation.
Methods: :
We used a device to stimulate quick cycles of near (25cm)/far (70cm) accommodation by displaying a visual object on a LCD screen. We prepared two kinds of objects, (C) and (F). (C): an object size was changed during far accommodation to keep the retinal projection size of the object constant. (F): an object size was fixed during far accommodation. Twelve myopic school-aged children were treated for short three sessions, 1st training with (F1), second one with (C) and third one with (F2). Each session was composed of 10 cycles. The pupillary size of both eyes during training was monitored and recorded with an infrared camera.
Results: :
The relative pupillary sizes (a size at a far point/a size at a near point) in right eyes were 99.7+/-3.6 (mean+/-SD, n=12) in F1, 92.3+/-6.9 in C, and 100.3+/-3.2 in F2. Statistical analysis by ANOVA showed that significant differences (p<0.005) were seen between F1 and C, and between F2 and C. The similar results were seen in left eyes, 98.4+/-5.0 in F1, 91.8+/-5.3 in C, and 99.2+/-2.9 in F2. These results indicated that the training with the size fixed object (F1) scarcely induced a pupillary constriction during far accommodation but that with the size-changed object (C) induced the constriction. This result was confirmed by the third training with F2 which also scarcely showed a pupillary constriction during far accommodation.
Conclusions: :
The training with the object whose projection size on the retina is kept constant is essential to induce a pupillary constriction during far accommodation resulting with great improvement of visual acuity of school-age myopic children.
Keywords: accomodation • pupil • myopia