Measurement of the visual axis through two different methods: quantification and differences for measuring chord μ

Abstract

To compare the differences between the apparent and actual chord μ. Methods: In this prospective, comparative, non-randomized, and non-interventional study, imaging examinations using Pentacam and the HD Analyzer were performed in the same room under the same scotopic conditions. The inclusion criteria were patients aged 21-71 years, able to provide informed consent, myopia up to 4D, and anterior topographic astigmatism up to 1D. Patients using contact lenses, those with previous eye diseases or surgeries, corneal opacities, corneal tomographic changes, or suspected keratoconus were excluded. Results: Altogether, 116 eyes of 58 patients were analyzed. The patients' mean age was 30.69 (±7.85) years. In the correlation analyses, Pearson's correlation coefficient of 0.647 indicates a moderate positive linear relationship between apparent and actual chord μ. The mean actual and apparent chord μ were 226.21 ± 128.53 and 278.66 ± 123.90 μm, respectively, with a mean difference of 52.45 μm (p=0.01). The analysis of mean pupillary diameter resulted in 5.76 mm using the HD Analyzer and 3.31 mm using the Pentacam. Conclusions: We found a correlation between the two measurement devices, and even though we found considerable differences, both can be used in daily practice. Given their differences, we should respect their peculiarities as well.

Repeatability and Agreement of Chord Mu between Scheimpflug Tomography and Swept-Source Optical Coherence Tomography

“…Given that pupil size decreases with age [ 29 ], differences in its value between previous studies [ 25 , 28 ] and our study may rise from the different age of cohorts. Previous studies included younger participants (30.69 ± 7.85 years [ 25 ] and 40.3 ± 16.9 years [ 28 ]) than in our study (mean, 67.2 ± 11.2 years). In addition, the devices use different principles.…”

“…There was a statistically significant difference (1.8 ± 1.2 mm, p < 0.01) between the measurements of the two devices for healthy eyes. Rodrigues et al [ 25 ] reported that Pentacam showed a shorter pupil diameter (3.31 mm; range, 1.87 to 5.23 mm), than the HD analyzer (5.76 mm; range, 2.50 to 8.60 mm).…”

Comparison of Visual Outcomes of Bilateral Dual-Technology Diffractive IOL versus Blended Enhanced Monofocal with Dual-Technology IOL

“…In addition, the lens' anterior surface is configured with a negative spherical aberration to counterbalance the cornea's positive spherical aberration. 15,16,[20][21][22][23][24][25][26][27][28][29][30] The advantages associated with the utilization of the TECNIS Synergy IOL in both eyes (hereinafter referred to as the ZFR00V IOL) and the potential enhancement of patient outcomes associated with the combined utilization of the TECNIS Eyhance and TECNIS Synergy IOLs (from now on referred to as ZFR00V/ICB00) remain unaddressed because of the lack of substantial evidence. 15,16,[20][21][22] Thus, we aimed to compare the clinical results associated with the use of ZFR00V in both eyes with those associated with the use of ZFR00V/ICB00.…”