The dearth of medical specialists in Third World
countries is well documented (e.g.; at the WHO and the World Bank). For example, considering the
ratio of 1:2 million optometrists per capita, in countries like Mali, it is
estimated that an optometry appointment would take up to 200 years. In response to
this crisis, the Child Vision™ Project, an Oxford University spin-off, distributes Harry Potter-looking spectacles with patented,
fluid-filled and self-adjustable lenses, to youth 12 to 18 years in Third World countries, for less
than one Euro ($1) per pair.
The spectacles are equipped with a small wheel, on
the temple of the frame. Adjusting the wheel, one way, pushes the fluid
contained in a chamber between two plastic lenses outwards, creating convex plus lenses for longsighted people.
Adjusting the wheel the other way, pushes the fluid inwards, creating concave minus lenses for shortsighted people.
Masterminded by physics Professor Joshua David Silver, at Oxford University
in the UK, the many aspects of this invention are recited in several patent families. One member of the patent families is the US utility patent US7085065, titled Variable focus optical apparatus.
US7085065 recites a variable focus lens apparatus, suitable for spectacles, comprising
a rigid lens and a flexible lens, forming a sealed chamber, wherein both lenses are secured with adhesive between two engaging rings, connected to the lens
frame. The recited invention differs from the prior art of variable focus
lenses, in that only one of the lenses is flexible, and the rings securing the two lenses do not have to be made of ductile
material, even though they still have to be light and resistant enough for use in spectacles. This inventive aspect of the variable focus lens apparatus expands the range of possible
materials used, while reducing the costs of production. The variable focus lens apparatus, thus designed for spectacles, is also suitable for lenses that are not necessarily circular. In this case, some cylindrical compensation for astigmatic errors, introduced in non-circular lenses, is carried over to the rigid lens.
Below, the abstract of this invention together with the patent Figure 2, depicting a cross-sectional
view of a first preferred embodiment of the variable focus lens apparatus, suitable
for spectacles. Specifically, the patent Figure 2 drawing shows the variable focus
lens apparatus 10, comprising a
rigid lens 22, and a flexible lens 16, forming the sealed cavity, in which clear fluid will be injected. The rigid lens 22
is secured with adhesive 24 to the
rings 12 and 14. The flexible lens 16
is stretched tightly between the engaging rings 12 and 14, at the step point
18 on ring 12, and recessed point 20
on ring 14, as indexed on the right
side of the apparatus, and shown on both sides.
A variable focus lens apparatus for use in spectacles or the like is formed from a fluid envelope comprising two sheets, at least one of which is flexible. The flexible sheet is retained in place between two rings, which are directly secured together. This may be by means of adhesive, ultrasonic welding, or any similar process. If the other sheet is rigid, then it may be directly secured to one of the rings. [Abstract US7085065]
References
Child vision™ Project
Child vision™ Project
World Bank Data
Physicians, hospital beds, surgical specialists,
midwives, health care workers -- per 1000 people
WHO - World Health
Report
https://www.who.int/whr/2006/overview/en/
