Assessment of Effects of Different Mydriatics on Choroidal Thickness by Examining Anterior Chamber Parameters

Background: Mydriatics drops have a broad range of applications in ocular examination and treatment. After administration, many changes can occur in the different parts of the eye including the choroidal layer which is a vascular layer localized between the outer sclera and inner retinal layers.

Purpose: To study effects of different mydriatics on choroidal thickness (CHT) by examining anterior chamber parameters (corneal thickness, corneal volume, corneal curvature, anterior chamber depth (ACD), anterior chamber volume (ACV) and anterior chamber angle (ACA).

Materials and methods: A total of 166 eyes of 83 students and employee aged 18-40 years old were enrolled in this crosssectional study. The participants were divided randomly into 3 groups based on application of drops (tropicamide group, phenylephrine group and cyclopentolate group). All subjects underwent a full ophthalmic examination involving; visual acuity and refraction, Slit- lamp biomicroscopy, Fundus examination, IOP measurement using noncontact tonometry, anterior chamber parameters measurement using Pentacam Rotating Scheimpflug Camera and the choroidal thickness measurement by Optical coherence tomography OCT.

Result: Decrease in the peri-temporal, inner-temporal, sub foveal, inner-nasal and peri-nasal choroidal thickness after drops instillation in all groups were found to be significant (𝑝 = 0.000, 𝑝 = 0.000, 𝑝 = 0.000, 𝑝 = 0.000 and 𝑝 = 0.000 respectively), while increase in the anterior chamber depth was found to be significant with all mydriatics (𝑝 = 0.00).

Conclusion: The study showed that while cyclopentolate, tropicamide, and phenylephrine cause a decrease in choroidal thickness, they also lead to increase in anterior chamber depth.

Keywords:Mydriatics; Choroidal thickness; Anterior chamber parameters; Pentacam; OCT

Abbrevations: Cht Peri_Tem_PRE, POST: Peri-Temporal Choroidal Thickness Pre-& Post Drop Instillation; Cht_Inner_Tem_PRE, POST: Inner-Temporal Choroidal Thickness Pre-& Post Drop Instillation; Cht_Subfoveal_PRE, POST: Sub Foveal Choroidal Thickness Pre-& Post Drop Instillation; Cht_Inner_Nas_PRE, POST: Inner-Nasal Choroidal Thickness Pre-& Post Drop Instillation; Cht_Peri_ Nas_PRE, POST: Peri-Nasal Choroidal Thickness Pre- &Post Drop instillation