Background: To evaluate the precision and accuracy of objective refraction measurement obtained with combinations of instrument design and technique. We also compared the performance of the instruments with subjective refraction measurements. Method and analysis: The objective refraction was measured in 71 subjects with three autorefractometers that have different designs and measurement principles (binocular with fogging, binocular without fogging, and monocular with fogging). Repeatability and reproducibility metrics were calculated for the objective refraction measurements. The agreement of the objective refraction measurements between the three instruments and the agreement with the subjective refraction measurements were evaluated. Results: All three autorefractometers had repeatability and reproducibility limits smaller than 0.70D. The smallest difference (0.10D) in the spherical equivalent was seen between the two binocular instruments. Compared with the subjective refraction, the binocular without fogging technique had the smallest mean difference in spherical equivalent (<0.20D) whereas the binocular fogging technique had the smallest limit of agreement interval (1.00D). For all comparisons, the mean difference and limit of agreement interval for the cylindrical components were lower than 0.10D and 0.75D, respectively. Conclusion: All three instruments evaluated had good repeatability and reproducibility. The binocular fogging technique provided the best agreement with subjective refraction.

Purpose: To assess the repeatability of individual and combined macula and optic disc volumetric analysis, and the agreement between both scan modes with optical coherence tomography (OCT) in glaucoma and healthy control eyes. Methods: 27 subjects with a previous diagnosis of glaucoma were included. The control group included 34 healthy subjects older than 50 years. Volumetric measurements of the macula and optic disc were performed with a spectral domain OCT. Two different scan protocols (individual and combined) were performed in each participant, and each scan mode was repeated three times. The retinal and ganglion cell complex thickness were analysed in nine and eight sectors respectively. The peripapillary retinal nerve fibre layer (pRNFL) thickness was analysed in 12 clock sectors from the optic disc area. The repeatability limit (Rlim) and agreement analysis were performed for each sector analysis. Results: For the retinal thickness, the differences in the Rlim between both scan modes was lower than 5 μm. The differences in the Rlim between the control and glaucoma groups were lower than 3 μm. The limits of agreement interval were lower than 20 μm for each population group. The ganglion cell complex measurements showed larger repeatability values for the combined scans for each group, and the limits of agreement intervals were lower than 13 μm. The differences in the Rlim between the control and glaucoma groups were lower than 3 μm. For the pRNFL thickness, the differences in the Rlim between both scan modes were lower than 10 μm. The control group showed lower repeatability values than the glaucoma group except on sectors 2 and 3. For both population groups, the horizontal sectors showed shorter limit of agreement intervals than the vertical sectors. Conclusions: Similar repeatability values were obtained between both scan modes in each population group. Both scan modes cannot be used interchangeable due to the wide limits of agreement.