Abstract
Purpose :
Treatment of severe microphthalmia/ anophthalmia (MICA) is aimed at creating facial symmetry often using orbital implants increasing in size to stimulate orbit and palpebral fissure growth in growing children. However, current treatments are not well-evaluated and often require invasive procedures. We developed a personalized conformer design based on images obtained from Magnetic Resonance Imaging (MRI) with the aim to treat patients with well-designed orbital implants which can be placed non-invasively and changed for a larger size at home. We performed a preliminary cohort study to test the treatment efficacy of these novel conformers.
Methods :
A cohort of four mixed gender babies was treated with a series of conformers. The subjects were selected based on their MICA diagnosis and their affected left orbits were analyzed. All subjects had a MRI simultaneously with an impression made to design a series of conformers of increasing size, which was made of NextDent Ortho Rigid, a biocompatible (Class IIa) poly-methyl methacrylate material, using a stereo-lithography printer (Rapid Shape). After placement of the first conformer by the ocularist, a set of conformers of increasing size was given to the parents. They were taught to replace the conformer for a larger one as soon as it would fit in the orbit. Treatment efficacy of these conformers was assessed by analysis of socket and eye cavity (socket and eye together) volumes, and horizontal palpebral fissure length (HPF).
Results :
Early evaluation showed that socket volumes of the treated eyes increased on average with 205% (up to 376% longer follow up) over time during treatment, indicating that socket expansion occurred. After treatment with conformers eye cavity volumes were on average 35% of reference eye volumes corrected for age whereas no treatment would have resulted in only 7.6%. The average HPF at the start of treatment was 50.9% of the reference value in the 5th percentile, whereas the last average measured HPF was 74.6% (up to 91% longer follow up) of the reference value, which may indicate that the conformer stimulates HPF growth. The conformers were well-tolerated by the subjects.
Conclusions :
Our study showed that our 3D-printed conformers are well-tolerated and noninvasively stimulate socket expansion and palpebral fissure growth. Therefore these conformers may successfully be used for the treatment of children with congenital MICA.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.