An Improved Ophthalmoscope.
Year: 1892

page_text: Date of Application, 9th Nov., 1892
Complete Specification Left, 8th Aug., 1893-Accepted, 4th Nov., 1893
An Improved Ophthalmoscope.
HENRY ROSBOROUGH SWANZY A.M. M.B. F.R.C.S.I. Examiner in Ophthalmic
Surgery to the University of Dublin and to the Royal University of Ireland
23 Merrion Square Dublin, and GEORGE PRESCOTT 9 Merrion Row Dublin,
Electrical Engineer and Optician do hereby declare the nature of this invention
to be as follows:-
The invention is an improved ophthalmoscope in which is combined various
mechanical and optical contrivances some of which have been used in other
instruments but have here been simplified in detail in such a manner as to produce an
instrument of the highest efficiency at a low price. The instrument consists of two
reversible mirrors attached to one side of a plate, on the other side of which is a disc
with lenses circumferentially arranged, the high efficiency of the instrument is attained
by having the lenses as close as possible to the mirrors, the accentuation of the position
of each lens is attained by a simple pin without any separate spring, additional
lenses are provided in a small rotatable piece moving concentrically with the disc.
The handle of ebonite is attachable without any metallic terminal, and the case is
of vulcanite.
Dated this 5th day of November 1892.
HENRY ROSBOROUGH SWANZY.
GEORGE PRESCOTT.
COMPLETE. SPECIFICATION.
An Improved Ophthalmoscope.
HENRY ROSBOROUGH SWANZY A.M. M.B. F.R.C.S. Examiner in Ophthalmic
Surgery to the University of Dublin and to the Royal University of Ireland
23 Merrion Square Dublin, and GEORGE PRESCOTT 9 Merrion Row Dublin
E.E. and Optician, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
Our invention is an improved ophthalmoscope in which is combined various
mechanical and optical contrivances some of which have been used on other
instruments but have here been simplified in detail in such a manner as to produce
an instrument of the highest efficiency at a low cost. The instrument consists of
two mirrors of the usual reversible order attached to one another by cementing
them back to back to an intermediate plate, and secured in the usual manner to one
side of another plate screwed to the handle of the instrument. On the other side
of this plate is a rotatable disc with lenses circumferentially arranged so that each
in its turn may be brought opposite the hole in the mirrors. The high efficiency
of the instrument depends upon the reduction of the diffraction to a minimum, and
this is chiefly attained by eliminating the usual spring catch, for holding each lens
in its turn opposite the hole in the ophthalmoscope, and using instead a simple
projecting pin, without any projecting spring, for accentuating the positions of the
lenses, thus allowing the plate between the lenses and the mirrors to be as thin as
the strength of the material will allow and so bringing the lenses and mirrors close
together.
The drawing shews at Fig. 1 the disc A with the lenses circumferentially arranged.
a one of the lenses, 6 small countersinkings or c nicks, into which a catch, shewn

page_text: in another drawing, fits, as each nick or countersink is brought opposite to said
catch. B shews the disc with lenses a¹ and countersinking in section.
Fig. 2 shews the intermediate plate C with the opening through which the
ophthalmoscopist looks, a boss d on which the disc with lens may be rotated, and
the simple projecting pin e to act as a catch in the countersinks or nicks of the lens
disc. G the screw for attachment to the handle of the instrument.
D. Fig. 2, shews the intermediate plate in section d' the boss, f₁ the opening,
el the simple projecting pin which acts as a catch. 9¹ the screw for the handle.
Fig. 3 shews the intermediate plate D with the rotatable disc placed in its proper
position B, on the boss d and held there by the screw C, f shewing the relative
positions of each lens and the hole in the intermediate plate.
Fig. 4 shews, also in section, the whole instrument put together, D the plate
already referred to, B the disc with lenses, C the concave mirror and the plane
one, both cemented back to back to an intermediate plate, E, in the drawing the
plane reflecting surface is next the intermediate plate, and f the hole through
the intermediate plate and mirrors, and one of the lenses in the disc opposite said
hole.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is,
An improved ophthalmoscope substantially as described.
HENRY ROSBOROUGH SWANZY.
GEORGE PRESCOTT.