Abstract
Background: No previous study in South Africa has used optical coherence tomography (OCT) in assessing corneal thickness changes following the instillation of an anaesthetic.Aim: The purpose of this study was to investigate the short-term effects of oxybuprocaine 0.4% on corneal thickness.Setting: The study was conducted at a university eye clinic in Westville, KwaZulu-Natal.Methods: A total of 34 (N = 34) participants, of both genders, aged 18–25 years participated in the study. Data collection commenced once ethical clearance was obtained. Baseline measurements of central corneal thickness (CCT) (within 0 mm – 2 mm of the corneal apex) and mid-peripheral corneal thickness (MPCT) (within 2 mm – 5 mm of the corneal apex) were taken using the Optovue iVue 100 OCT. Measurements were obtained using the standard iVue 100 corneal pachymetry map. One drop of oxybuprocaine was then instilled using a sterile technique in the right eye (RE) of each participant. Central and MPCT measurements were obtained using the OCT at time intervals of 30 s for the first 2 min and then for 60-s intervals up until 5 min. Baseline central and MPCT were then measured for the left eye (LE) using the OCT. The effect of two drops of oxybuprocaine on CCT was also investigated on the left eye only using the same procedure as on the right eye.Results: There were minimal fluctuations of the CCT and MPCT in the 5 min following instillation of either one or two drops of oxybuprocaine. The fluctuation of both the CCT and MPCT was within 10 µm irrespective of dosage and returned to baseline thickness after 5 min.Conclusion: Clinically, short-term CCT and MPCT changes following the instillation of oxybuprocaine are not large enough to affect the accuracy of Goldmann applanation tonometry.
Highlights
The cornea serves as the primary refractive surface of the eye[1] and as a surface against which intraocular pressure measurements (IOP) can be taken, among other things
Central corneal thickness (CCT) has been shown to have a substantial effect on IOP readings obtained by GAT8,9,10, with previous studies demonstrating a positive correlation between CCT and IOP.[11,12]
Following instillation of one drop of oxybuprocaine HCL 0.4%, the CCT was observed to increase from the mean deviation of the baseline readings within the first 30 s
Summary
The cornea serves as the primary refractive surface of the eye[1] and as a surface against which intraocular pressure measurements (IOP) can be taken, among other things. Goldmann applanation tonometry (GAT) is widely accepted as the international gold standard for direct contact IOP measurements.[2] The accuracy of GAT measurements depends on many factors including corneal thickness, curvature and axial length.[3] It has been shown that an accurate reading of IOP using GAT is obtained with a corneal thickness of about 0.52 mm.[4] thicker corneas lead to an overestimation of IOP and thinner corneas to an underestimation of IOP.[4,5,6,7] Central corneal thickness (CCT) has been shown to have a substantial effect on IOP readings obtained by GAT8,9,10, with previous studies demonstrating a positive correlation between CCT and IOP.[11,12]. No previous study in South Africa has used optical coherence tomography (OCT) in assessing corneal thickness changes following the instillation of an anaesthetic
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
