Influences of Tropicamide on Anterior Segment Parameters with Pentacam in Healthy Individuals Melis Palamar, Zerrin Alkan, Sait Egrilmez, and Ayse Yagci Abstract Background: This study aims to investigate the effects of tropicamide 1% on the main numerical parameters of anterior segment with the Pentacam rotating Scheimpflug camera in healthy individuals. Methods: Pentacam measurements of 50 (25 female and 25 male) healthy individuals before and after 25 min of tropicamide 1% instillation were performed and compared. For comparison of the test parameters, paired t-test was used in the groups. Results: Mean age in the study group was 28.40 – 4.58 years (range 18–35 years). Measurements between 2 sessions were significantly different for the parameters of anterior chamber depth (ACD) and anterior chamber volume (ACV) (P < 0.05). Conclusions: Tropicamide 1% instillation leads to a significant increment in ACD and ACV measurements. Effects of tropicamide on these parameters for Pentacam measurements should be considered to ensure exact clinical interpretation in ophthalmologic practice. Introduction E valuation of anterior segment parameters is an im- portant component of ophthalmic examination. Imaging of the anterior segment has traditionally been carried out with slit-lamp biomicroscopy, but objective quantitative as- sessment of anterior segment parameters was limited. Also direct visualization of the anterior chamber angle (ACA) could only be carried out with the help of diagnostic con- tact lenses. However, new developed devices such as the Pentacam rotating Scheimpflug camera (Oculus Optikgera ¨te GmbH, Wetzlar, Germany) promises quantitative informa- tion and qualitative imaging of the anterior and posterior surfaces of the cornea, anterior chamber depth (ACD), ACA, iris, and lens. 1 The assessment of the anterior segment parameters may enable important information that helps our knowledge and understanding of ocular pharmacokinetics, aqueous humor dynamics, primary open-angle glaucoma, and pigmentary glaucoma. Additionally, quantitative documentation of alter- ations in anterior segment parameters may provide useful in- formation for accurate intraocular lens (IOL) power calculation, piggyback IOL implantation, and IOL exchange surgeries. Tropicamide is a medication that is almost routinely used in ophthalmologic examination to provide temporary mid- riasis. It is a tropic acid derivative endowed with short du- ration of antimuscarinic activity. It is available in 0.5% and 1% ophthalmic solutions. Its maximum effect is achieved in about 20–25 min and lasts about 20 min, with complete re- covery being in *6 h. 2,3 The effects of tropicamide on cor- neal thickness in myopic patients, the effects of intraocular pressure, and anterior segment parameters in children were studied earlier. 4,5 In this prospective study, we aimed to investigate the in- fluences of tropicamide 1% instillation on ACD, anterior chamber volume (ACV), ACA width, central corneal thick- ness (CCT), mean astigmatism, and keratometry in healthy individuals. To the best of our knowledge, the alterations in these parameters in healthy adult population have not been previously reported. Methods A total of 50 healthy individuals (25 male and 25 female) with no refractive errors (emetropic) with the mean age of 28.40 – 4.58 years (range 18–35 years) were enrolled. None of the individuals had corneal pathology, glaucoma, uveitis, posterior segment pathology, history of previous eye surgery or trauma, history of using topical/systemic medications or systemic diseases, which could interfere with the eye struc- ture. None of the individuals had the history of contact lens use for any reasons (refractive, cosmetic, etc.). All cases were evaluated before and 30 min after instilla- tion of one drop of tropicamide 1% with the Pentacam. The Department of Ophthalmology, Faculty of Medicine, Ege University, Izmir, Turkey. JOURNAL OF OCULAR PHARMACOLOGY AND THERAPEUTICS Volume 29, Number 3, 2013 ª Mary Ann Liebert, Inc. DOI: 10.1089/jop.2012.0145 349