Renesto Ada C, Melo LA Jr, Sartori Mde F, Campos M Sequential topical riboflavin with or without ultraviolet a radiation with delayed intracorneal ring segment insertion for keratoconus. Am J Ophthalmol. 2012 May;153(5):982-993.e3. doi: 10.1016/j.ajo.2011.10.014. Epub 2012 Jan 20.
Schellini SA, Matai O, Igami TZ, Padovani CR, Padovani CP [Essential blepharospasm and hemifacial spasm: characteristic of the patient, botulinum toxin A treatment and literature review]. Arq Bras Oftalmol. 2006 Jan-Feb;69(1):23-6. Epub 2006 Feb 10. Review. Portuguese.
Scott AB, Kennedy RA, Stubbs HA Botulinum A toxin injection as a treatment for blepharospasm. Arch Ophthalmol. 1985 Mar;103(3):347-50.
Wollensak G, Spoerl E, Seiler T Riboflavin/ultraviolet-a-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. 2003 May;135(5):620-7.
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
