Ĭonsidering that iTrace, IOLMaster, and Pentacam are commonly used keratometry devices and Barrett toric calculator is a relatively good toricity calculator in a clinical setting, we aimed to compare the differences in toricity calculated on the basis of the data obtained by the aforementioned three devices and the Barrett toric calculator in this study. Moreover, a recent study demonstrated that astigmatism prediction errors with and without posterior corneal curvature measured and calculated using the updated Barrett toric calculator showed similar results. Many toric IOL calculation methods have been reported, but studies demonstrated that the Barrett toric calculator showed better performance than did the other calculators. Considering that iTrace and IOLMaster 500 measure corneal curvature using data centered on the apex, the Pentacam-measured anterior axial keratometry data on the 3âmm-diameter ring centered on the corneal apex were used in this study. Anterior corneal astigmatism data, as computerized values focused on the anterior 3.0âmm-diameter region of the cornea, can be centered on the corneal apex or pupil. Furthermore, it can image and perform automated measurement of the anterior and posterior corneal surfaces. The Pentacam Scheimpflug imaging system (OCULUS, Wetzlar, Germany) can capture 25â50 images by rotating 360° in one examination. IOLMaster 500 (Carl Zeiss Meditec, Germany) measures anterior corneal astigmatism and curvature by analyzing the real position of each pair of reflection spots (six spots of light arranged in a hexagonal pattern) from the anterior surface of the cornea with an approximately 2.3â2.5âmm-diameter ring. ITrace ray-tracing aberrometry (Tracey TM Technologies, Texas, USA), on the basis of corneal topography, can provide simulated keratometry (SimK) and astigmatism data with a 3.0âmm-diameter ring centered on the anterior corneal apex. Different types of keratometers (ray-tracing aberrometry, partial coherence interferometry, and Scheimpflug imaging system) may provide different corneal astigmatism values for the same eye, which might provide different toricity choices for toric IOLs, even with use of the same formula. Currently, there is no standard device for measuring corneal astigmatism and calculating toric IOL in a clinical setting. Rational surgical planning (toric intraocular lens (IOL), clear corneal incision at the steepest axis, peripheral corneal relaxing incisions, etc.) plays an important role in astigmatism correction. IntroductionÄ«ecause postoperative visual quality of patients with cataract is affected by both surgically induced astigmatism (SIA) and preoperative corneal astigmatism, the use of optimal size and location for clear corneal incision and measurement of precise preoperative corneal astigmatism should both be considered for improving postoperative visual quality in patients undergoing cataract surgery. Differences in toric IOL power and toricity calculated using anterior keratometry data from iTrace, IOLMaster 500, and Pentacam should be noted in clinical practice. There were differences in toricity calculated using data from the three devices ( ). The toric IOL power calculated using data from the three devices showed the following trend: iTraceâ>âIOLMaster (0.49â±â0.36, ) and Pentacam (0.39â±â0.42, ) and Pentacam was agreement for measurement and calculation was assessed using a paired sample t-test and a nonparametric test. Toricity and toric IOL power were calculated using the online Barrett toric calculator. The main outcome measures were corneal cylinder power, axis of astigmatism, and keratometry values. The analysis included 101 eyes (101 subjects) with regular astigmatism. To investigate the interdevice agreement for differences in toric power calculated using data on anterior corneal astigmatism obtained with corneal topography/ray-tracing aberrometry (iTrace), partial coherence interferometry (IOLMaster 500), and Scheimpflug imaging (Pentacam).
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