Here is the design of a clinical trial:

Official Title: Cataract Online Refraction Evaluation: A Multi Center Randomized Controlled Trial

Included conditions:
- Cataract

Study Armgroups:
- {'label': 'Telemonitoring', 'type': 'OTHER', 'description': 'Subjects in the telemonitoring group will have post-operative follow-up measurements involving teleconsultations, remote eye exams and health questionnaires.', 'interventionNames': ['Other: remote monitoring after cataract surgery']}
- {'label': 'Usual care', 'type': 'NO_INTERVENTION', 'description': 'Subjects in the usual care group will receive regular post-operative care, mostly involving in-hospital consultations.'}

Interventions:
- {'type': 'OTHER', 'name': 'remote monitoring after cataract surgery', 'description': 'remote monitoring after cataract surgery', 'armGroupLabels': ['Telemonitoring']}

Primary Outcomes:
- {'measure': 'Cost-effectiveness', 'description': 'The main outcome measure will be Incremental cost-effectiveness ratio (ICER), defined as euros per QALY, and compared between the two groups.', 'timeFrame': 'pre-operative until 3 months after surgery'}

Please estimate the sample size based on the assumption: 
A standard deviation of 0.30 logMAR, an α of 0.05, a power of 90%, 20% loss to follow-up, and using a one-sided, one sample t-test.
Study population and sample size calculation
        Patients planned for bilateral cataract surgery without visual acuity influencing comorbidities are eligible for study participation. The surgical procedures can be performed on the same day (i.e. immediate sequential) or on two different days. Exclusion criteria are: cataract surgeries combined with other procedures (including keratoplasty, vitrectomy, glaucoma filter implants), presence of ocular comorbidities that negatively influence post-operative visual acuity (such as amblyopia, age-related macular degeneration, diabetic retinopathy, glaucoma or uveitis), insufficient command of the Dutch, German or English language, no access to a smartphone and computer/tablet, and inability to successfully perform the demo version of the web-based eye exam.
        The sample size calculation is based on determining the validity of the web-based eye exam since calculations based on cost-effectiveness and safety were not feasible. We aim to assess whether the corrected distance visual acuity obtained with the web-based refraction is not significantly worse than the visual acuity obtained with the manifest refraction. We assume no difference between the measurements and consider a difference up to 0.10 logMAR to be non-inferior. With a standard deviation of 0.30 logMAR (a commonly used SD in power calculations on visual acuity [29â31]), an Î± of 0.05, a power of 90, 20% loss to follow-up and using a one-sided, one sample t-test, 94 eyes are then required in the telemonitoring group (so 47 participants, as all measurements will be performed bilaterally). This results in a total study population of 94 participants (188 eyes) for both study groups.