An ophthalmoscope is usually a complex optical instrument used for examining the retina of humans and animals. Generally, ophthalmoscopes have more than twenty lenses and from three to six lights and, as such, are intricate and costly to manufacture and buy.
Examples of such know types of ophthalmoscope are disclosed in GB-A-2235308, GB-A-2204144, WO-A-2000/30527 and DE-A-3714041.
Ophthalmoscopes are used routinely during the day-to-day work of doctors, optometrists, veterinary surgeons, health workers and trainees of the above.
However, due to the expensive nature of this instrument, only limited numbers are available for actual use and certainly there is no way that an ophthalmoscope can be provided for each, for example, doctor who needs to use one.
Due to the shortage of these instruments and their complexity, students and even non-specialised medical staff very often do not get a chance to learn how to use this instrument properly.
This situation is worse in less developed and third world countries where in some places there are no ophthalmoscopes available to local doctors or aid workers, because they are simply too expensive to buy or manufacture.
The problem of the restricted numbers of ophthalmoscopes in hospitals, opticians and veterinary surgeries, along with the associated lack of expertise in using the instrument, when available, is therefore potentially serious and any attempt to reduce the complexity of the instrument and the manufacturing costs, is sought.
“Manufacture and Use of Homemade Ophthalmoscopes: a 150th Anniversary Tribute to Helmholtz” a publication from BMJ, 23-30 Dec. 2000, Vol 321, p1557-1559, discloses a simple ophthalmoscope. This instrument, although much simpler and cheaper to produce than standard ophthalmoscopes, has a major problem in that the sight hole through which the retina is observed, causes glare in the observer's eye, thereby severely reducing the view.
Any method of producing cheaply a simple ophthalmoscope which eliminates, or at least substantially reduces, the problems commonly associated with the simple ophthalmoscope disclosed in the above mentioned paper, is therefore sought.