Virtual ophthalmic instrument gallery

On the following pages we provide information on instruments for refraction, surface examination of the eye and internal illumination. There are instruments for checking your existing spectacles or lenses and even some quite sophisticated chairs!

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Explore the following pages in this virtual gallery

Take a seat

First the patient needs somewhere to sit.


We check the power of your existing spectacles.

Test charts

Look for the letters!


We measure rays of light as they are reflected by the retina.

Ophthalmoscopes (part 1)

The principal diagnostic test, examining the eye for disease.

Ophthalmoscopes (part 2)

Ophthalmoscopes (part 3)


Assessing the visual field.


Mapping the surface of the eye.

Slit lamps

For examining the cornea and the interior of the eye.

Duochrome tests

Used in conjunction with the crossed cylinder.


Tonometers measure the internal pressure of the eye and tonometry is one of the principal tests for glaucoma, but until relatively recently their use in the eye examination was far from routine. A patient's intraocular pressure (IOP) should normally be 15. Any reading in the region of 21 or 22 signifies an increased likelihood that the patient will go on to develop glaucoma.

Trial frames

Most people associate the eye examination with 'those funny glasses the optician makes you wear'. These are called trial frames and, despite competition from automatic refracting units, they remain one of the optometrist's most important pieces of kit.


Sometimes our two eyes don't work properly in conjunction with each other. 'Orthoptics' is the study, diagnosis and (non-surgical) treatment of anomalies of binocular vision, strabismus ('squint') and monocular functional amblyopia. Its treatment involves the use of exercises, prisms or patching.


This section of the museum website is particularly important because many historic instruments are too large to display in our small exhibition rooms. We can still 'collect' them, however, by taking photographs, collecting instruction manuals or preserving the trade catalogues issued by the manufacturers. The museum can often identify mysterious pieces of equipment found by the public.

Note that our Virtual eye and vision gallery is where you can find out about the most sophisticated optical instrument of all...the human eye itself.