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. 2023 Mar;71(3):818-823.
doi: 10.4103/ijo.IJO_1175_22.

Effect of mydriatic eye drops (combined 0.8% tropicamide and 5% phenylephrine) on the measurements of corneal parameters using Pentacam

Pawan Prasher  1 , Vipan K Vig  2 , Brahmjot Singh  3 , Rajan Sharma  4 , Ashok Sharma  5
Affiliations

Effect of mydriatic eye drops (combined 0.8% tropicamide and 5% phenylephrine) on the measurements of corneal parameters using Pentacam

Pawan Prasher et al. Indian J Ophthalmol. 2023 Mar.

Abstract

Purpose: The purpose of the study is to investigate the effects of combined 0.8% tropicamide and 5% phenylephrine on the corneal parameters using Pentacam.

Methods: The study was performed on 200 eyes of 100 adult patients visiting the ophthalmology clinic for evaluation of refractive errors or cataract screening. Mydriatic drops (Tropifirin; Java, India) containing tropicamide 0.8%, phenylephrine hydrochloride 5%, and chlorbutol 0.5% (as a preservative) were instilled into the eyes of the patients three times every 10 minutes. The Pentacam was repeated after 30 minutes. The measurement data of various corneal parameters from different Pentacam displays (keratometry, pachymetry, densitometry, and Zernike analysis) was manually compiled on an Excel spreadsheet and analyzed using Statistical Package for the Social Sciences (SPSS) 20 software.

Results: Analysis of Pentacam refractive maps revealed a statistically significant increase (P < 0.05) in the values of radius peripheral (cornea front), pupil center Pachymetry, pachymetry apex, thinnest location Pachymetry, and cornea volume. However, pupil dilation did not affect the Q-value (asphericity). Analysis of the densitometry values revealed significant increase in all zones. Aberrations maps revealed statistically significant increase in the value of spherical aberration after the induction of mydriasis, but the values of Trefoil 0º, Trefoil 30º, Koma 90º, and Koma 0º were not affected significantly. We did not observe any untoward effect of the drug, except transient blurring of vision.

Conclusion: The current study showed that routine mydriasis in the eye clinics leads to a significant increase in various corneal parameters including corneal pachymetry, cornea densitometry, and spherical aberration as measured by Pentacam, which can influence the decision-making in the management of various corneal diseases. The ophthalmologists should be aware of these issues and make adjustments in their surgical planning accordingly.

Keywords: Cornea; Pentacam; corneal tomography; keratoconus; refractive surgery screening.

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Conflict of interest statement

None

Figures

Figure 1
Figure 1
Representative refractive maps of a patient showing various corneal parameters at baseline (a) and after mydriasis (b). Note the increase in pupil center pachymetry from 522 μm at baseline to 534 μm after mydriasis
Figure 2
Figure 2
Representative densitometry maps of a patient showing increase in various corneal densitometry values in different zones and different depths after mydriasis (b) from baseline (a)
Figure 3
Figure 3
Representative higher-order aberration maps of a patient showing various corneal aberrations at baseline (a) and after mydriasis (b). Note the change in spherical aberrations from 0.360 μm at baseline to 0.394 μm after mydriasis
See this image and copyright information in PMC

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