| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[11] Fixed-dose combination therapy: Cox JA, Mollan SP, Bankart J, Robinson R. Efficacy of antiglaucoma fixed combination therapy versus unfixed components in reducing intraocular pressure: a systematic review. Br J Ophthalmol. 2008;92(6):729‐734. https://pubmed.ncbi.nlm.nih.gov/18460539/
Fixed-dose combination therapy: Olthoff CM, Schouten JS, van de Borne BW, Webers CA. Noncompliance with ocular hypotensive treatment in patients with glaucoma or ocular hypertension an evidence-based review. Ophthalmology. 2005;112(6):953‐961. https://pubmed.ncbi.nlm.nih.gov/15885795/
Fixed-dose combination therapy: Chrai SS, Makoid MC, Eriksen SP, Robinson JR. Drop size and initial dosing frequency problems of topically applied ophthalmic drugs. J Pharm Sci. 1974;63(3):333‐338. https://pubmed.ncbi.nlm.nih.gov/4820359/
Fixed-dose combination therapy: Serle JB, Toor A, Fahim MM, Polikoff LA, Ellison J. The Effect of Varying Dosing Interval on the Efficacy of Intraocular Pressure Lowering Drugs. Invest Ophthalmol Vis Science 2004;45(5):971 https://iovs.arvojournals.org/article.aspx?articleid=2406778
Fixed-dose combination therapy: Pisella PJ, Pouliquen P, Baudouin C. Prevalence of ocular symptoms and signs with preserved and preservative free glaucoma medication. Br J Ophthalmol. 2002;86(4):418‐423. https://pubmed.ncbi.nlm.nih.gov/11914211/