Observational studyCornea2018
Effect of Cataract Surgery on the Refractive Index of the Cornea Estimated by Optical Pachymetry.
Observational study in Cornea, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
2 citing papers in PubMed.
- The influence of routine uncomplicated phacoemulsification on the orthogonality of the cornea.Indian journal of ophthalmology · 2021Article
- The Impact of Changes in Corneal Back Surface Astigmatism on the Residual Astigmatic Refractive Error following Routine Uncomplicated Phacoemulsification.Journal of ophthalmology · 2020Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
purposeTo noninvasively estimate the refractive index (RI) of the central cornea along the antero-posterior direction before and after routine phacoemulsification.
methodsUsing 2 setups for a standard optical pachymeter, the ratio of observed optical section widths (OSWs) is a function of the RI. Thus, the corneal RI could be estimated using a calibration equating OSW ratios with known RI values. The OSW was measured by 2 observers for 1) normal subjects for estimating interoperator errors and effects of sex and age on the RI and 2) before and after patients underwent routine phacoemulsification.
resultsFirst, the average interoperator difference (ΔRI) was +0.0005 (SD = ±0.0044, 95% confidence limit, -0.0002 to +0.0012). The root mean square difference between measurements obtained by the observers was 0.0032. There was a significant correlation between the ΔRI and the mean of each pair of measured values (r = -0.172, n = 153, P = 0.003). The mean RI (±SD) was 1.435 (±0.005, n = 82) for females and 1.429 (±0.005, n = 71) for males. There was no significant between-sex difference or association between the RI and age (mean age, ±SD, and range, 44.31, 20.38, and 19-88 years, respectively). Second, the difference (y) between the preoperative (x) and postoperative RI was, y = 0.844x - 1.203 (r = 0.694, n = 31, P ≤ 0.001) according to observer 1 and according to observer 2, y = 0.755x - 1.108 (r = 0.681, n = 31, P ≤ 0.001).
conclusionsThe RI of the human cornea along the antero-posterior axis can be estimated using a modified application of traditional optical pachymetry. The average values for the corneal RI were higher compared with those reported in previous reports. The change in the RI after phacoemulsification could be predicted from the preoperative value.
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