Custom Print Megnetic Levator Prosthesis Pilot Comparison

Extensive description of the study protocol is provided in the Research Strategy (R), but key components are summarized and justified here. This is a prospective, interventional, single-arm, single-group open label study. Because the primary objective of this study is to perform prototyping in the interest of developing and determining the feasibility of our novel approach, randomization to treatment or control is not necessary or appropriate at this stage. All participants will have ptosis and will be fitted with the experimental custom adjustable force MLP. Determining if the custom MLP is superior to the non-custom MLP is beyond the scope of this phase I SBIR project.

The primary outcome is custom MLP fitting success defined as 8mm interpalpebral fissure size or greater, patient desire to engage in a 20-min trial, and comfort rated greater than 5 out of 10 after the 20 minute trial (all criteria must be met). These criteria may be met at any one visit in the prototyping process. Therefore, one prototype may fail but if subsequent prototypes succeed, the case will be rated as a success. Selection of the criteria was based on a desire to have both objective and subjective metrics. Eye opening of 8mm was selected because it is a functional amount of eye opening found to be useful to patients in prior studies (note that these patients do not have inferior lid malposition). We have used interpalpebral fissure as a primary outcome as opposed to Marginal Reflex Distance (distance from the corneal reflection to upper lid) in order to allow enrollment of bilateral and severe cases, and to provide a common outcome for both eye opening and closing on the blink. Desire to engage in a 20-minute trial was selected as a criteria because it provides some information on the patient's opinion of the device. Comfort greater than 5 out of 10 indicates better than neutral, and was selected as a minimum goal for success (median comfort in our prior study was 8 out of 10).

The statistical analysis method for the primary outcome will be an exact binomial test of one proportion to determine which condition is met for more than half of patients. If the prototype approach is successful for greater than half of patients after 20 minutes of wear there will be a large enough sample for a phase II study to warrant continued development.

Sample Size Calculation for primary outcome: With 10 subjects we will have 80% power to show that the success rate significantly exceeds 50% with a one-sided alpha=0.05 exact binomial test of one proportion when the success rate is 8/10 or greater, meaning 8 would have to succeed to reach significance. With 15 subjects the success rate would need to be 11 to reach significance.