Biomedical Engineering Reference
In-Depth Information
Table 1
Clinical outcome measures relevant to ophthalmology (
16
)
Endpoint
Notes
Best corrected visual
acuity (BCVA)
Repeated measurements over time to a prespecified primary time point
(often 12 months) should be made. Providing data from a single time
point might be considered questionable, although a specific time point
should be indicated as the primary endpoint.
% of patients who gained
15 letters BCVA
Common primary outcome measure. Often referred to as “responders.”
Needs to be backed up by other secondary visual outcome measures
because dichotomizing a continuous variable will result in a loss of
information.
% of patients with gain/
loss/no change
Valuable secondary outcome measures. A change of
10 letters is often
considered the minimally clinically relevant improvement that can be
perceived by patients and may be used to define visual gain/loss/no
change. Loss of BCVA should be included in definition of treatment
failure.
Mean BCVA
May be acceptable as primary outcome if suitable secondary outcome
measures are included.
Mean change in BCVA
Common secondary outcome measure. May be acceptable as primary
outcome if suitable secondary outcome measures included. May be
preferred as the primary outcome in noninferiority studies.
Visual fields
Rarely proposed as primary endpoint, but has been accepted as such in
some cases if supported by test-retest reliability, sensitivity, and
feasibility in the actual patient group as well as information to support
the clinical relevance of any changes seen.
Contrast sensitivity
Generally a secondary outcome measure.
Automatic perimetry
Generally a secondary outcome measure.
Anatomical assessments
Generally secondary outcome measures. Example: macular thickness.
Patient-reported outcomes Generally secondary or exploratory outcome measures. Need to be well
validated to be accepted by regulatory agencies.
identifying clinically relevant changes (the minimal improvement
that can be perceived by patients or has an impact on vision-related
tasks). The definition of clinically relevant improvement should be
prospectively defined. A list of potential specific endpoints is
provided in Table
1
[
16
].
Patient-reported outcome measures (PROs) should be used
with care in phase III clinical trials. Patient-reported outcomes are
of increasing interest to physicians because, if well-designed, these
outcomemeasures can provide an important measure of both patient
satisfaction with their treatment and the impact of the disease and its
treatment on patient's daily lives. Regulatory agencies, however,
