Training eyes
Practising the basic principles of imaging and photographing the eye is made much easier using training devices such as those illustrated below.
Two training eyes are described below ,the first can be manufactured in short order with minimal equipment whilst the second is multi-part 3D printed device.
Below is a copy of a presentation I gave to the lovely bunch of vets at the IEOC in Iceland (June 2018). Please get in contact if you have any comments, queries or suggestions.
Check out the facebook page for details of where I sourced the various lenses used at www.facebook.com/equineeyeclinic
Best wishes
Tim
Two training eyes are described below ,the first can be manufactured in short order with minimal equipment whilst the second is multi-part 3D printed device.
Below is a copy of a presentation I gave to the lovely bunch of vets at the IEOC in Iceland (June 2018). Please get in contact if you have any comments, queries or suggestions.
Check out the facebook page for details of where I sourced the various lenses used at www.facebook.com/equineeyeclinic
Best wishes
Tim
1) "Easy" training eye
Shopping list:
1) a 50mm diameter childrens "play pit ball"
2) a 50mm focal length converging lens e.g.
a) 1x 20Dioptre indirect lens
b) 1x 50mm diameter 50 mm focal length bo convex converging lens ( theses are sold widely for educational optics experiments for schools and can be readily found on ebay, Amazon or via a specialist lens supplier or
c) 2x 50mm diameter cabachons/glass domes - these are readily available for jewelery and projects. Placed flat side to flat side two 50mm diameter glass cabachons form a biconvex converging lens with an approximate focal length of 50mm.
3) Cardboard tube cut to form a carrier for the lens to allow it to be secured to the plastic "globe"
4) A printed retinal image
1) a 50mm diameter childrens "play pit ball"
2) a 50mm focal length converging lens e.g.
a) 1x 20Dioptre indirect lens
b) 1x 50mm diameter 50 mm focal length bo convex converging lens ( theses are sold widely for educational optics experiments for schools and can be readily found on ebay, Amazon or via a specialist lens supplier or
c) 2x 50mm diameter cabachons/glass domes - these are readily available for jewelery and projects. Placed flat side to flat side two 50mm diameter glass cabachons form a biconvex converging lens with an approximate focal length of 50mm.
3) Cardboard tube cut to form a carrier for the lens to allow it to be secured to the plastic "globe"
4) A printed retinal image
| Equine iris images to print out for training eyes (50mm) |
| Equine fundus image - cut out and then make 4 radial cuts to allow folding into ball |
2) 3D printed training eyes: free to download and use
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These models were designed to mimic the equine and small animal eye for the training of Veterinary Surgeons and students in the art and science of ophthalmoscopy and ophthalmic photography.
The training models requires 2x glass cabochons (glass domes - used for jewellery making, freely available e.g Amazon, eBay) to construct the anterior chamber/lens simulacrum. Placed together, flat surface to flat surface, they create a spherical lens. A pair of 50mm diameter cabachons creates a lens of approximately 20 Dioptre focal length and is used for the equine training model whilst a pair of 30mm cabochons creates a lens of approximately 30Dioptre focal length and is used for the small animal model.
Simulated iris/pupils are either 3D printed or printed on paper and then sandwiched between the two cabochons. The assembled lens/iris/anterior chamber is then rested on the retaining ring at the top of the model. The lid is placed on top to secure the lenses.
A retinal image is printed onto photographic paper approx. and the retinal image placed in to the slot at the bottom of the models.
Opaque and translucent lens and corneal lesions can be simulated using white correction liquid (Tipex) or marker pens. Lesions can be painted on to the surface of the 3D printed iris simulacra or alternatively iris simulacra can be printed and the pupil cut out.
The training models requires 2x glass cabochons (glass domes - used for jewellery making, freely available e.g Amazon, eBay) to construct the anterior chamber/lens simulacrum. Placed together, flat surface to flat surface, they create a spherical lens. A pair of 50mm diameter cabachons creates a lens of approximately 20 Dioptre focal length and is used for the equine training model whilst a pair of 30mm cabochons creates a lens of approximately 30Dioptre focal length and is used for the small animal model.
Simulated iris/pupils are either 3D printed or printed on paper and then sandwiched between the two cabochons. The assembled lens/iris/anterior chamber is then rested on the retaining ring at the top of the model. The lid is placed on top to secure the lenses.
A retinal image is printed onto photographic paper approx. and the retinal image placed in to the slot at the bottom of the models.
Opaque and translucent lens and corneal lesions can be simulated using white correction liquid (Tipex) or marker pens. Lesions can be painted on to the surface of the 3D printed iris simulacra or alternatively iris simulacra can be printed and the pupil cut out.
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