A tooth to restore sight

A team in Marseille restored partial sight to blind patients, thanks to a complex and rare surgical technique known as the osteo-odonto-keratoprosthesis.

The osteo-odonto-keratoprosthesis is a mixed bone-tooth-Plexiglas prosthesis. The idea is to use the patient's tooth structure to support an artificial ocular prosthesis, a Plexiglas cylinder that works as a fixed focus lens. The prosthesis enables light to reach the retina and therefore serves to restore sight.

The first step involves removing a tooth, usually a canine, associated with a part of the jawbone, and to prepare the tooth in order to obtain a flat side. The Plexiglas used as a lens is inserted into the tooth and the mixed prosthesis thus obtained is implanted in the patient's mouth in order to promote vascularisation and fibrosis. Three months later, the prosthesis is extracted from its temporary location in order to be permanently implanted into the eye. The operation is performed in two 3-hour sessions.

In total, three patients from hospitals in Marseilles benefitted from this highly complex and advanced surgical technique conducted by Pr. Louis Hoffart of the la Timone ophtalmology department and Pr. Laurent Guyot of the hôpital Nord's maxillofacial department. 

The patients, who were between the ages of 50 and 60, had bilateral corneal blindness and had previously received corneal transplants that were unsuccessful because the ocular surface was too severely damaged. They have now partially recovered their sight. Two of the patients who could previously only perceive light now have a visual acuity of 1/10th.
"On average, the patients gain 4/10ths of visual acuity" stated Pr. Hoffart. According to certain publications, patients could gain up to 7/10ths of visual acuity.

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