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Agreement Between Pentacam and Handheld Auto-Refractor/Keratometer for Keratometry Measurement; [Concordancia Entre El Sistema Pentacam Y Un Auto-Refractometro/Queratometro Portatil Para La Medicion De Queratometria] Publisher Pubmed



Hashemi H1 ; Heydarian S2 ; Ali Yekta A3 ; Aghamirsalim M4 ; Ahmadipishkuhi M1 ; Valadkhan M1 ; Ostadimoghaddam H5 ; Amiri AA6 ; Khabazkhoob M7
Authors
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Authors Affiliations
  1. 1. Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
  2. 2. Department of Rehabilitation Science, School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran
  3. 3. Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
  4. 4. Eye Research Center, Tehran University of Medical Sciences, Tehran, Iran
  5. 5. Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
  6. 6. Department of Ophthalmology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
  7. 7. Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Source: Journal of Optometry Published:2019


Abstract

Objective: This study was conducted to evaluate the level of agreement in keratometry measurements between a rotating Scheimpflug imaging-based system (Pentacam) and a handheld auto-refractokeratometer (handheld NIDEK ARK-30). Method: This analytical cross-sectional study was conducted in the right eyes of 579 subjects. Keratometry measurements were conducted with the Pentacam and the handheld NIDEK ARK-30 systems. The SPSS Software version 22 and MedCalc V3 were applied to estimate descriptive statistics using paired t-test, Pearson correlation coefficient, 95% limits of agreement (LoA), and Bland–Altman plot. Results: In the total sample, the inter-device difference in the mean flat and steep keratometry values was −0.266 diopter (D) (P-value < 0.001) and 0.052 D (P-value = 0.093), respectively. There was a significant difference in mean flat keratometry between the two devices in all groups of refractive errors (paired difference <0.5 D and P-value < 0.001). The difference in mean steep keratometry was significant only in myopic subjects (P-value = 0.046). The 95% LoA between the two devices measurements was 2.51 D, 3.98 D, and 6.37 D for flat keratometry and 2.6 D, 3.2 D, and 3.9 D for steep keratometry in emmetropic, myopic, and hyperopic subjects, respectively. Conclusion: Our study showed relatively wide limits of agreement between handheld NIDEK ARK-30 and Pentacam; therefore, these devices cannot be used interchangeably for measuring corneal curvature. © 2019 Spanish General Council of Optometry