## 2 Materials and Methods
### Calibration Lenses  
Since we were unable to find calibration intraocular lenses, we measured the accuracy of the instrument with three precision calibration lenses, with high positive power, to verify that the nominal power matches the labeling and complies with ISO standards. These three calibration lenses were plano-convex lenses fabricated from RoHS-compliant N-BK7 glass (Thorlabs Inc., Germany, (THORLABS)) and they possessed a high positive power comparable to the usual power of an intraocular lens to be implanted in an eye under normal conditions. All lenses had a diameter of 12.7 mm. The LA1207 lens had a focal length of 99.7 mm, center thickness of 2.2 mm, and power in air of +10.00 D; the LA1213 lens had a focal length of 49.8 mm, center thickness of 2.6 mm, and dioptric power in air of +20.00 D; and the LA1289 had a focal length of 29.9 mm, center thickness of 3.2 mm, and power in air of +33.33 D.  
The manufacturer of the three high-power calibration lenses provides the necessary data (radius of curvature, thickness, index of refraction, etc.) to compute the power profile using Zemax Optics Studio (Zemax Corporation, Version 22.3 (2022)). These physical characteristics of the calibration lenses were incorporated into the NIMO to perform the measurements. To check the precision of the NIMO TR1504, we computed the power profiles of the calibration lenses and compared them to the ones measured with the NIMO. We also checked the repeatability of the power profiles by measuring the power profile of each calibration lens and several intraocular ones ten times in a row. To measure the power profile, we followed the same methodology for each calibration lens. We measured the average power profile ten times using the NIMO. To ensure concentration, we employed a custom mount designed and manufactured at the Universidad Complutense de Madrid (UCM) workshop. This allowed us to completely remove the lens and place it again on the sample platform for the next measurement without significantly changing the lens centration. As a consequence, all subsequent measurements showed accurate lens centering, eliminating any systematic errors due to centering. Additionally, we computed the theoretical power profile using the \"pupil map\" tool in the ray tracing software Zemax Optics Studio (Zemax Corporation, Version 22.3 (2022)). Applying a standard set of tolerances, in accordance with the lens manufacturer's specifications, we also computed the tolerance limits, which indicated the maximum change in the theoretical profile when small random errors were introduced in the constitutive parameters of the lens. From the theoretical and measured power profiles, we have estimated the systematic and random error of the NIMO for the calibration lenses. The random error is defined [21; 22] as  
\[\sigma_{P}=\left(\frac{1}{N-1}{\sum_{i=1}^{N}}\frac{1}{2a}{\int_{-a}^{a}{(P_{i}(x )-P_{m}(x))^{2}dx}}\right)^{\frac{1}{2}} \tag{1}\]  
where \(N\) is the number of measurements, \(P_{i}(x)\) is the \(i\)-th profile measured, \(P_{m}(x)=\sum_{i=1}^{N}P_{i}(x)\) is the average of the measured profiles (represented as a continuous blue line in Figure 1), and a is the aperture radius. The systematic error is defined as  
\[\delta P=\frac{1}{2a}{\int_{-a}^{a}{(P_{m}(x)-P_{l}(x))dx}} \tag{2}\]  
Figure 1: Power profiles for three ophthalmic calibration lenses of +10.00, +20.00, and +33.33 D. (**A–C**) show the power profile from the center to the periphery. (**D–F**) show the power profiles in the central area amplified for better visualization. Dashed blue lines indicate the confidence interval of the measurement. Dashed red lines represent the tolerance limits. Black dashed lines indicate the extension of the central zone of the lens within a circle of 0.50 mm diameter. Notice that the maximum aperture radius for (**C**) is lower than that of (**A**,**B**) due to the limitations of the NIMO TR1504.