Oh, patents! Child Vision™ Project variable focus lenses

Copyright © Françoise Herrmann

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

http://www.vdwoxford.org/childvision/

World Bank Data

Physicians, hospital beds, surgical specialists, midwives, health care workers  -- per 1000 people

https://data.worldbank.org/indicator/SH.MED.PHYS.ZS

WHO - World Health Report

https://www.who.int/whr/2006/overview/en/

https://www.who.int/whr/2006/overview_fig6_en.pdf?ua=1