What is 'it'?

Dear Ms. Brainy,

Subject:  The original poster simply observed that
the refractive STATE goes DOWN in our
modern "environment" as a natural process.

Here is the data to confirm her initial observations
about the eye's dynamic behavior.

============================================

REPORT ON THE REFRACTIVE STATES OF THE EYE.

A recent study in Hong Kong showed what other studies have
shown - wearing less than a full correction will slow the
progress of the myopia. Children selected for the study were
between the ages of 9 and 12. All were nearsighted, with 1.00
to 5.00 D of myopia. The children were separated into three
groups. Each group was given a different type of eyeglasses
to wear for the two-year period of the study. The first group
wore single vision lenses with a full correction; the second
group wore progressive lenses with a +1.50 add; the third
group wore progressive lenses with a +2.00 add. All children
were examined at 6-month intervals to check the progression of
their myopia. Sixty-eight children completed the study. As
expected, more undercorrection meant slower myopia
progression.

Minus vision lenses: - 1.23 D increase (2 years)
-0.625 per year

Progressive lenses with +1.50 add: - 0.76 D increase (2 years)
- 0.38 per year

Progressive lenses with +2.00 add: - 0.66 D increase (2 years)
-0.33 per year

Source: Leung JT, Brown B. Progression of myopia in Hong Kong
Chinese schoolchildren is slowed by wearing progressive
lenses. Optom Vis Sci 1999; 76:346, 354. Published 10/07/00.

==================

The results of the natural eye "adapting" to
12 to 16 years in a "school" environment:

MYOPIA PREVALENCE IS ALWAYS HIGHER THAN 90 PERCENT
FOR TAIWAN MEDICAL STUDENTS

Re: Changes in ocular refraction and its components
among medical students - a 5-year longitudinal study", Optom.
Vis. Sci., 73:495-498, 1996) found that in a study of 345
National Taiwan University medical students, the myopia
prevalence increased from 92.8% to 95.8%! over the five year
period.

******************

1) In Singapore, the vision of 421,116 males between the ages of
15 and 25 was examined. In 1974-84, 26.3% were myopic; in
1987-91, 43.3% were myopic. Both the prevalence and severity
of myopia were higher as the level of education increased.
The prevalence rate was 15.4% in males with no formal
education and increased steadily through the education levels
to reach 65.1% among the university graduates in 1987-91. The
authors state that their findings confirm indications from
other sources that the association between the prevalence and
severity of myopia and education attainment is real (M.T.
Tay, K.G. Au Eong, C.Y. Ng and M.K. Lim, "Myopia and
Educational Attainment in 421,116 Young Singaporean Males,"
Ann Acad Med Singapore, 1992, Nov;21(6):785-91).

2) Regarding the prevalence of myopia in Asian countries, Lam and
Goh (Lam, C.S. and Goh, W.S., "The incidence of refractive
errors among schoolchildren in Hong Kong in relationship with
the optical components", Clin. Exp. Optom., 74:97-103, 1991)
found that in 383 school children from ages 6 to 17 years, the
prevalence of myopia increased from 30% at ages 6-7 years, to
70% at ages 16-17 years.

3) Lam and Yap (Lam, C.S. and Yap, M. "Ocular dimensions and
refraction in Chinese Orientals", Proc. Int. Soc. Eye Res.,
6:121, 1990) found that in a group of optometry students at
The Hong Kong Polytechnic University, the prevalence of myopia
was 75% in females and 69% in males.

4) Goh and Lam (Goh, W.S. and Lam, C.S., "Changes in refractive
trends and optical components of Hong Kong Chinese aged 19-39
years," Ophthal. Physiol. Opt., 14:378-382, 1994) found that
in 2000 first-year students at the University of Hong Kong,
the prevalence of myopia was 87.5%.

5) Lin et al (Lin, L.-K, Chen, C.J., Hung, P.T., and Ko, L.S.,
"National- wide survey of myopia among schoolchildren in
Taiwan, Acta Ophthalmol.", 185:29-33, 1988) found that in a
national survey of children in Taiwan, the prevalence of
myopia was over 70%.

6) Lin et al (Lin, L.K., Shih, Y.F., Lee, Y.C., Hung, P.T., and
Hou, P.K., " Changes in ocular refraction and its components
among medical students - a 5-year longitudinal study", Optom.
Vis. Sci., 73:495-498, 1996) found that in a study of 345
National Taiwan University medical students, the myopia
prevalence increased from 92.8% to 95.8%! over the five year
period.