All eyes on 3M abrasives at Moorfields Eye Hospital

Moorfields Eye Hospital in London, the world-renowned centre of ophthalmic medical excellence, has found a unique application for industrial abrasive wheels made by 3M, the diversified technology company, and uses them in the finishing and refining process of its prosthetic eyes. By using the Scotch-Brite EXL Unitised Wheel XL-UW by 3M Moorfields can quickly and precisely create ocular prosthetics of superb quality that frequently transform the lives of patients and their families.

Ocular prostheses
Moorfields Hospital, working in conjunction with UCL (University College London) Institute of Ophthalmology, is the oldest and largest centre for ophthalmic treatment and research in Europe. It forms one half of the most successful hospital-university partnership for ophthalmology in the world. Moorfields' ocular prosthetics department is the largest of its type in the UK, and every year that department fits, manufactures and finishes around 1,400 custom-made ocular prostheses, each individually hand-tailored to the patient. 

The department also fits temporary prosthetic eyes and cosmetic shells for patients who are either awaiting a customised prosthesis, or who wish to cover some form of disfigurement or eye loss.

Customised ocular prostheses are usually made for patients who have lost an eye or eyes, or whose eyes have been damaged or otherwise affected by a range of ocular conditions. At Moorfields, customised artificial eyes are hand-made from medical grade acrylic plastic. They are finished with an abrasive - a vital part of the process as there is a need to trim down the acrylic and remove flash without leaving grinding marks on the finished product. 

Each custom-made eye takes around seven hours to complete and is hand-painted in front of the patient to ensure a perfect match to their own eye colour; problems with colour and finish are more likely to occur if the prosthetic is painted in a different location.

The process
The process of producing a customised prosthetic eye begins when the patient makes a first visit to the ocular prosthetics department and an impression is made of their eye socket, in much the same way that dentists take impressions to make dentures. 

The ocular impression thus created is used as a mould to produce a wax shape, which fits into the socket and is used by Moorfields' ocularists to position the iris, perfect the shape and ensure correctness of gaze. The wax shape is then itself cast into a mould, which is filled with acrylic plastic that is trimmed back using the Scotch-Brite EXL Unitised Wheel XL-UW. 

Thereafter the prosthetic is further painted, with the addition of veins and any necessary tinting of the sclera (white of the eye), as well as any changes that might be needed to the iris, and it is then refined again using the same Scotch-Brite Wheel. 

After this, the final product is polished and is complete. Most artificial eyes last for several years, although in children, who are still growing, they have to be replaced more often. In the meantime, patients must look after them carefully and have them polished regularly.

Very often, patients who have just lost their eye, or who are awaiting a custom-made prosthetic, are fitted with a temporary eye from Moorfields' stock. These eyes are supplied in half-sphere forms, resembling half a table-tennis ball, and must be ground down and shaped with great precision, if they are to fit the patient ideally. Moorfields uses a Scotch-Brite EXL Unitised Wheel XL-UW for this purpose, too.

Novel use
David Carpenter, Chief Ocularist at Moorfields Eye Hospital, appreciates that ocular prosthetics represent a novel use for the Scotch-Brite Wheel, which is most frequently used to deburr metal parts. However, he is quick to explain why he favours this particular product.

Carpenter has used 3M Grinding Wheels in his medical work for many years, but recently discovered that the 3M abrasive he used most often had been discontinued. That led to a conversation with his 3M representative, who sent David various sample 3M wheels to try and, when the decision had been made, located a supplier. 

The Scotch-Brite EXL Unitised Wheel XL-UW is made of a compressed, non-woven fibre that gives it a uniform grain distribution, leading to consistent results. The EXL material is very tough, with an aggressive cutting action and is therefore ideal for deburring edges and corners without causing any damage to the part. The wheels are available in a range of sizes and with fine, medium and coarse grades, and are particularly suited for work with all types of metal.

Ideal solution
For Carpenter, the advantages of the 3M product are clear. The wheels are available in sizes that are ideal for the application, which gives operatives great control, and the wheels come in a range of grades that allow the action to be fitted precisely to the purpose. They also complete the task efficiently and much more quickly than the alternative option of using tungsten carbide burrs. 

In an acute medical setting where speed, precision and aesthetics are all very important, the ability of the Scotch-Brite EXL Unitised Wheel XL-UW to achieve a precise finish without leaving any trace of its own action on the prosthetic represent huge advantages over other forms of abrasion, trimming and finish.

For many of the patients at Moorfields Eye Hospital, their custom-made prosthetic eye represents a huge leap forward in terms of quality of life, self confidence and social integration. For children, in particular, a well fitting prosthetic can offer vital support to facial features, allowing them to grow into and maintain an appropriate form for the rest of that patient's life.


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