To rebuild the eye socket after removal of a blind eye
Orbital Implants are usually used to replace either the entire eye or to fill an eviscerated eye. Think of the normal eyeball as an inflated balloon, once the eye had been enucleated or eviscerated, it looks like a deflated balloon and requires an implant to be placed in the coats of the eyeball or eye socket to restore volume. Rarely, when there is severe shortage of conjunctival lining and volume (e.g. secondary to an exposed ball implant) a dermis fat graft is recommended (harvested from your buttock or abdomen)
Four to six weeks after surgery, a prosthetic or artificial eye (which looks like a big contact lens), is placed over the implant. When the muscles of the eye socket move, the artificial eye moves too.
Types of Orbital implants
Integrated implants are made of a permeable material , which allows the tissue in the eye socket to grow into it, thus making it part of the body. The commonly used integrated implant has been developed from coral, which is processed to match human bone and is called Hydroxyapatite (HA), another variety is Medpor.
Integrated implants are more expensive than other types of implant and may not be suitable for all patients (whose sockets have been damaged by radiotherapy or post extensive trauma and loss/shortage of the lining of eyeball).
Non-integrated implants are made of a solid material, such as polymethylmethacrylate (PMMA), which is a type of acrylic plastic. When a non-integrated implant is fitted into the eye socket, it is either placed within the coats of the eyeball (after an evisceration) or wrapped in a mesh, to which the muscles are attached (post enucleation), reducing the risks of migration or extrusion.
After healing, the artificial eye (or prosthesis) is fitted and inserted. The artificial eye can also be pegged on to the orbital implant, which allows them to have a larger range of movement than they otherwise would. Pegging is generally carried out approximately a year after implant has been inserted.
Frequently Asked Questions
What are the potential risks & complication of Enucleation/ Evisceration, Orbital Implants & wearing an Artificial Eye?
After Enucleation or Evisceration, there is a tendency of the lining of the eye socket (conjunctiva) to shrink over time. This can be controlled/ reduced to a significant extent by wearing an artificial eye constantly. In addition, the tissues of the eye socket can undergo shrinkage, causing the upper and lower lid sulcus/fold to look deep and hollow (called post enucleation socket syndrome)
1. Contracted left socket due to erratic artificial eye wear, with resultant upper & lower lid entropion and inability to retain artificial eye
2. 2 months post left socket reconstruction (using lining of the mouth), patient now able to retain artificial eye and no entropion.
Although wearing a larger prosthesis can reduce this appearance, the associated increase in weight can cause the lower lid to sag (ectropion). This can also present as instability of the prosthesis (falls out easily) or drooping of the eyelid (ptosis). As a result a few patients ask for additional surgery to improve the aesthetic appearance by either, correcting the ptosis, tightening the lower lid or improving the volume (removal of old implant & insertion of larger implant, placement of a orbital floor implant or injection of fillers). Your surgeon will discuss the best options for you.
The artificial eye or prosthesis has certain inherent issues related to movement, never achieving full range of movement as a normal eye. Range of movement can be improved by pegging or by reducing the size of the artificial eye at the inner & outer corners.
Some patients develop an allergic response to the artificial eye, causing chronic discharge, which can be avoided by annual ultrasonic cleaning of the prosthesis.
After insertion of an orbital implant, there is a low risk of extrusion, migration or infection of the implant.
Pegging of the implant can occasionally result in infection and extrusion of implant, and a clicking noise when the eye moves.
Procedure of Removal of an Eye & insertion of an Orbital Implant
The procedure is performed in an operating theater as day surgery under general anesthetic.
The procedure takes approximately 60-90 minutes. The contents or entire eyeball is removed and an appropriate size orbital implant is placed in the eye socket, and tissues are closed over it.
A temporary clear plastic shell (conformer) is fitted on top of the implant for a month after surgery to prevent the socket shrinking and give some shape while the socket heals.
The eye is padded shut for the first 48 hrs and on removal, when you open your lids, you will see the moist pink lining of the socket (like the inside of your mouth). The conformer will look like a clear plastic shell with a hole in the center, which allows for instillation of the eyedrops. This conformer will stay in place until you are fitted with an artificial eye in 4-6 weeks. During this period the pink colour of the lining will change to white.
The ocular prosthetist will create a detailed artificial eye to match the natural eye, this process can take up to a few days or weeks to perfect.