Eyes of Tomorrow: Osteo-Odonto-Keratoprosthesis Innovations

Aakanksha Pathania, B.Optom

Tutor, Vision Science Academy Learning Centre (VSALC)

Vision Science Academy Exclusive

The eyes are commonly known as the “windows to the soul,” and the cornea is often likened to the “front window of the eye.” Unfortunately, the loss of an eye is one of the most prevalent sensory organ impairments. Corneal disease ranks as the second leading cause of blindness globally, following cataracts. Its epidemiology is intricate, encompassing a variety of infectious and inflammatory eye conditions. ⁽¹⁾

Severe corneal disease often requires corneal graft surgery called penetrating keratoplasty. When the ocular surface is severely compromised, keratoprosthesis is the only option for restoring sight in these cases.  ⁽¹⁾

In 1963, Strampelli developed Osteo-Odonto-Keratoprostheses (OOKP) ^(1), which was later modified by Falcinelli (MOOKP). ⁽²⁾ This unique solution is designed for patients with bilateral corneal blindness and end-stage ocular surface disease that cannot be managed with other surgeries. ⁽³⁾ It is also used for autoimmune diseases and chemical injuries such as Stevens-Johnson syndrome, Toxic epidermal necrolysis, and others. ⁽³⁾

This keratoprosthesis procedure involves the removal of a tooth root and surrounding bone to create an osteo-odonto lamina, which is then fitted with an optical cylinder. It doesn’t only contain the autologous tooth but also alveolar bone with its ligament and periosteum, all covered by autologous oral mucosa. The procedure has shown success in treating severe cases of various eye conditions. However, it is a complex and time-consuming procedure that requires sacrificing oral structures. ⁽²⁾

The MOOKP is implanted in a complex physiological environment that depends partly on the patient’s medical history. The sides of the MOOKP support frame are in contact with the buccal mucous membrane graft. This allows integration because the soft tissue grows into the bone pores, improving implant fixation. The lower part of the support frame is in contact with the cornea and with aqueous humour, which could circulate around the posterior part of the optical cylinder. ⁽²⁾

However, the treatment is not for paediatric patients due to their undeveloped dental arches and higher risk of laminae resorption, as well as patients with Phthisis bulbi and no light perception, and those with retinal detachment and unrealistic expectations. Caution is advised for patients with defective light perception, mentally unstable patients, poor compliance or unreliable follow-up, and maxillofacial deformities. ^(3,5)

Although it is important to first assess the patient thoroughly, focusing on their eyes. This includes a comprehensive history and examination.

During the examination, it is crucial to measure the patient’s ability to see light and colours, and to measure the pressure inside their eyes. This helps to accurately diagnose glaucoma before any surgery, as it is the most common complication leading to vision loss in patients with MOOKP. ⁽³⁾

Before proceeding with dental surgery, the dentist will thoroughly examine your mouth and determine the best approach for treatment. It is important to use special mouthwashes and abstain from smoking before the surgery to ensure the best possible outcome. Additionally, the doctor will assess your face, neck, and airway to ensure the safest and most effective administration of medicine. ^(3,4)

The OOKP is the preferred artificial cornea for people with advanced corneal blindness. Modern OOKP surgery has shown it can help restore vision for people who are registered as blind, allowing them to read, recognise faces, and navigate unfamiliar places. Using a tooth as an eye implant could lead to new ways for eye doctors to work together and give the best care to patients. ⁽¹⁾

References:

1. Kaur, J. (2018). Osteo-odonto keratoprosthesis: Innovative dental and ophthalmic blending. The Journal of Indian Prosthodontic Society, 18(2), 89-95.
2. Viitala, R., Franklin, V., Green, D., Liu, C., Lloyd, A., & Tighe, B. (2009). Towards a synthetic osteo-odonto-keratoprosthesis. Acta biomaterialia, 5(1), 438-452.
3. Falcinelli, G., Falsini, B., Taloni, M., Colliardo, P., & Falcinelli, G. (2005). Modified osteo-odonto-keratoprosthesis for treatment of corneal blindness: long-term anatomical and functional outcomes in 181 cases. Archives of Ophthalmology, 123(10), 1319-1329.
4. Tan, A., Tan, D. T., Tan, X. W., & Mehta, J. S. (2012). Osteo-odonto keratoprosthesis: systematic review of surgical outcomes and complication rates. The ocular surface, 10(1), 15-25.