Related Experiment Video
Updated: Feb 3, 2026

Author Spotlight: Advancements and Challenges in Surgical Treatments for Postamputation Pain
Published on: March 8, 2024
Subconjunctival 0.1% epinephrine versus placebo in maintenance of mydriasis during vitrectomy: a randomized
Rafael B de Araújo1, Breno M S Azevedo2, Thais S Andrade2
11Division of Ophthalmology, Hospital Universitário Onofre Lopes, Universidade Federal do Rio Grande do Norte, Rua Mipibu, 741 apt 1402A, Natal, RN 59014-480 Brazil.
Background:
Pupil dilation and mydriasis maintenance throughout vitreoretinal surgeries are important to allow satisfactory fundus visualization and reduce risk of complications. The purpose of this study is to evaluate the role of subconjunctival epinephrine 0.1% injection in mydriasis maintenance during vitrectomy.
Methods:
Ninety-nine consecutive patients undergoing vitrectomy were enrolled. All subjects were preoperatively dilated with tropicamide 1%. Each patient was randomly allocated either in the epinephrine or placebo group. In epinephrine group, patients were submitted to a 0.2 cc subconjunctival injection of a 0.1% epinephrine solution just before first incisions. In placebo group, the same procedure was performed with 0.2 cc of saline 0.9%. Horizontal pupil diameter was measured with calipers before and in the end of the procedure.
Results:
Patients in the epinephrine group showed a significantly larger mean pupil diameter in the end of the surgery compared to placebo. There was a significant increase of mean pupil diameter from the beginning to the end of the surgery in such patients. Blood pressure was significantly higher in the epinephrine group than in placebo group. No other adverse effects were noted.
Conclusion:
Subconjunctival epinephrine is effective for maintaining and increasing pupil size during vitrectomy, compared to placebo. Caution should be taken regarding intraoperative blood pressure levels.
Trial Registration:
RBR; RBR-3qzhvg; Registered 8 May 2018-Retrospectively registered, http://www.ensaiosclinicos.gov.br/rg/RBR-3qzhvg/.
More Related Videos
Related Concept Videos
The Placebo Effect
Clinical Trials: Overview
Trial and Error and Algorithm
Clinical Trials
There are four phases in a clinical trial. A phase one...
Random Error
Random Variables
Uppercase letters such as X or Y denote a random variable. Lowercase letters like x or y denote the value of a random variable. If X is a random variable, then X is written in words, and x is given as a number.
For example, let X = the...

