ArticleBMC ophthalmology2026
Changes in chord µ and chord α after FS-LASIK and PRK in low-to-moderate myopia: a comparative study with vector analysis.
Article in BMC ophthalmology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
purposeTo comparatively evaluate changes in chord µ and chord α after photorefractive keratectomy (PRK) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) in eyes with low-to-moderate myopia using linear change (Δ) and displacement vector (DV) analysis.
methodsThis retrospective comparative case series was conducted at Istanbul University, Istanbul Faculty of Medicine. A total of 102 eyes from 56 patients who underwent PRK or FS-LASIK for myopia ± astigmatism were examined. Topographic measurements were performed using the Pentacam AXL preoperatively and at postoperative months 1 and 6. Changes in chord µ and chord α values were evaluated using Δ and DV analyses.
resultsAt 6 months, chord µ increased from 0.15 ± 0.10 mm to 0.23 ± 0.12 mm, and chord α from 0.35 ± 0.14 mm to 0.41 ± 0.14 mm, with Δ values of 0.08 ± 0.07 mm and 0.06 ± 0.13 mm, respectively (p = 0.013 and p = 0.020). The increases were greater in the PRK group (p = 0.044 and p = 0.018), whereas DV magnitudes did not differ between groups (p > 0.05). Δ chord α correlated positively with pupil diameter, whereas Δ chord µ correlated negatively with trefoil (0°) and vertical coma, and chord µ DV correlated negatively with horizontal coma.
conclusionSignificant increases in chord µ and chord α were observed after both PRK and FS-LASIK, with a greater increase in the PRK group. These findings may aid the interpretation of chord parameters in eyes that may later undergo multifocal intraocular lens implantation.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.