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Yu-Cherng Chang, Florence Cabot, Siobhan Williams, Giovanni Gregori, Marco Ruggeri, Sonia H Yoo, Jean-Marie A Parel, Fabrice Manns; Pre-operative Prediction of Post-cataract Surgery IOL Position Using Anterior Chamber Depth and Lens Thickness Determined with Extended-depth OCT. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2717.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the precision of post-cataract surgery IOL position prediction using anterior chamber depth (ACD) and lens thickness (LT) as determined with extended depth Optical Coherence Tomography (OCT)
Five eyes from four patients (34, 64, 77, and 79 years old) undergoing cataract surgery were imaged before and 1 month after the procedure using a custom-built extended depth OCT system which produces whole eye images ranging in depth from the cornea to retina (Ruggeri et al, Biomed Opt Express 3:1506-1520; 2012) (8.6 frames/s, 400 A-lines/B-scan, 8 µm axial resolution; Figure 1). Pre- and post-operative anterior chamber depth (ACD) and pre-operative lens thickness (LT) were determined along the A-line passing through the corneal apex. A linear regression was performed to model the relationship between pre-operative ACD and LT, and post-operative IOL position (post-operative ACD) according to the formula: post-operative ACD = pre-operative ACD + C x LT, where C is an empirically-derived constant (T Olsen and Hoffmann, J Cat Ref Surg 40:764-773; 2014). The prediction error was quantified by comparing the predicted and measured post-operative IOL position.
Average pre-operative ACD, LT and post-operative ACD were 2.76 ± 0.59, 4.68 ± 0.44, and 4.24 ± 0.55 mm, respectively. The value of the C-constant derived from the five eyes was 0.315 ± 0.012. The residual error of the linear regression was less than 85 µm for all eyes (average of 45.4 ± 27.8 µm; Figure 2) corresponding to a refractive error of less than 0.2 D in a hyperopic eye.
Pre-operative ACD and LT derived from extended-depth OCT can be used with the C-constant method to predict post-cataract surgery IOL position.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
Figure 1: Example pre- (left) and post-operative (right) OCT images from the 79 year old subject.
Figure 2: Scatter plot of measured post-operative IOL position (post-operative measured ACD) and prediction error for each eye.
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