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G. Cleary, T. Ong, C. Jenkins; Astigmatic Shift From Subtenon Anaesthesia Related Ocular Rotation . Invest. Ophthalmol. Vis. Sci. 2005;46(13):781.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To quantify the effect of subtenon anaesthesia on ocular rotation and thus astigmatic shift preoperatively. Setting: Ear, Eye and Mouth Unit, Maidstone Hospital, Maidstone, Kent, United Kingdom. Methods: This prospective study included patients (n=31) who underwent subtenons local anaesthesia preoperatively. Eyes were marked at the inferior limbus then photographed in the primary position, both before and 5 minutes after subtenons local anaesthesia. Using Adobe Photoshop©, these photographs were analysed to calculate ocular rotation from the centre of the cornea; rotation was measured at the marked inferior limbus, and at distinctive iris markings and conjunctival vessels. Results: The mean absolute ocular rotation was 3.24° (Range 15.87°, Std. Deviation 3.2°). Incyclotorsion was observed in 68% of eyes, the remainder excyclotorting. 23% of eyes demonstrated rotation of 4° or more. There was no significant difference between the measurements obtained at different ocular landmarks. Conclusions: The degree of ocular rotation after subtenons anaesthesia is usually small; however the possibility of larger rotations must be taken into account when planning on–axis incisions to reduce preoperative astigmatism. We recommend marking preoperatively when refractive surgery is performed.
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