The procedures used today to duplicate the anatomy of the ocular orbit are exact replicas with a direct alginate impression. Any movement in the ocular orbit is transferred to the prosthetic eye with this method.
The wax form duplicating the parameters of the ocular orbit is fabricated and placed on the mold once the trial fitting is accepted after the trial fitting in the ocular orbit.
The mold of the ocular orbit is replicated in stone and the wax form is invested for a final curing mold.
The wax form is removed and replaced with acrylic (methyl-methacrylate), and heat cured to form a hard rigid form, that becomes the integral part of the final finished prosthesis. All proper cosmetics are applied and cured.
The finished product will sit on the face of the implant that was surgically imbedded in the ocular orbit; this implant will have encompassed around it the movement muscles and covered with the conjunctiva tissues. When the eyes move in conjunction with each other, the implanted orbit will follow the movement. With the prosthetic eye sitting upon the face of the implant, it will be pushed in the directions that are initiated by the natural eye. This is how the prosthetic eye gets its movement.
Movement is determined by the position and motility of the implant. This is only possible when the impression of the ocular orbit is correct and the wax form is properly seated to make a mold that replicates the natural ocular orbit.
MOVEMENT can only be ATTAINED WHEN AN IMPLANT IS PROPERLY POSITIONED IN THE OCULAR ORBIT BY THE OPERATING PHYSCIAN.
When an eye maker follows protocol in the manufacturing of a Prosthetic Eye as mentioned in the above technique, he will get MAXIMUM movement transferred to the Prosthesis.
Artificial Eyes (Prosthetic Eye) have for many years prior to the advent of WW 11 been constructed of glass by artisans from Europe. These eyes were made from silica (glass) and fire formed such as a light bulb. They were virtually a vacuum that was fragile and would etch from body acid, causing replacement much more often than a plastic (Prosthetic Artificial Eye).
After WW11 the availability of silica from Europe became very difficult to obtain. Other materials and methods became necessary to fabricate the Prosthetic Artificial Eye. This instituted 3 teams from the Military Dental Departments to develop and solve this problem. These teams consisted of personnel who were experienced in the prosthetic field in working with plastics and art forms. They were chosen from the Dental Prosthetic Schools of Bethesda Naval Training Center and Walter Reed Army Hospital in Washington D.C. They collaborated in their development of the modern day Prosthetic Artificial Eye. This decision was made due to the eye loses of our military at that time. These methods were passed on to the civilian industry by persons who gained this expertise while in the military.
The present day Prosthetic Artificial Eyes are made from (methyl –methacrylate) commercially known as ACRYLIC. This is a synthetic compound that is in two parts. Monomer (liquid) and (Polymer (powder), they are mixed to produce a putty like consistency, then packed in a compression mold to be cured to solidity. This forms the base for the application of the cosmetic duplication of the natural eye. All applications are in a vehicle of the same material, so that they have the same chemical bonding capability. This makes a totally solid product that is resistant to breakage and is malleable enough to allow adjustments and not alter the consistency of the material.
This product when properly cured and finished has proven to (be totally inert) and will not subject the contacting tissue to be affected in any way. This material over a period of time (normally 3 to 5 years) will absorb body fluid that can become adverse to the tissues they contact. This fluid can contain bacteria and acids that will cause irritations and discomfort to the affected area. Replacements are necessary to correct this so as to eliminate these symptoms, and regain a healthy ocular orbit.
Through proper notifications to our patients, this clinic advises these patients to maintain proper hygiene and maintenance, to prevent any problems that can arise from complacency and neglect . They are reminded that the prosthesis must and I say must have their prosthesis cleaned –pumiced and polished every 3 to 6 months to remove accumulated Plaque (protein that builds up on the tissue bearing surfaces).This Plaque is the main cause of irritation to the tissues, such as excessive excreta, soreness, and possible infections.
My advice is that: “Proper Periodical Maintenance will save you a lot of physical and mental discomfort”.
These products are not permanent, they must be replaced periodically.