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Comparison of objective and subjective refractive surgery screening parameters between regular and high-resolution
J Bradley Randleman1, Jihan Akhtar1, Michael J Lynn1
1From the Department of Ophthalmology (Randleman, Akhtar) and the Department of Biostatistics and Bioinformatics (Lynn), Rollins School of Public Health, Emory University, and Emory Vision (Randleman, Akhtar), Emory Eye Center, Atlanta, Georgia, the Cleveland Clinic Cole Eye Institute (Dupps, Krueger), the Department of Biomedical Engineering (Dupps), the Lerner Research Institute and the Transplant Center (Dupps), Surgery Institute, Cleveland Clinic, the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, Ohio, the Department of Ophthalmology (Klyce), Mount Sinai School of Medicine, New York, New York, USA; Instituto de Olhos Renato Ambrósio (Ambrósio), Rio de Janeiro Corneal Tomography and Biomechanics Study Group (Ambrósio), Rio de Janeiro, the Department for Ophthalmology of the Federal University of São Paulo (Ambrósio), São Paulo, Brazil.
Purpose:
To compare objective and subjective metrics from regular and high-resolution Scheimpflug devices (Pentacam) to determine their equivalence and interchangeability for refractive surgery screening.
Setting:
Emory Vision at Emory University, Atlanta, Georgia, USA.
Design:
Retrospective comparative case series.
Methods:
Eyes of consecutive screened refractive surgery patients were evaluated with high-resolution and regular Scheimpflug devices. Objective parameters evaluated included keratometry (K) values, central corneal thickness (CCT), and device-generated keratoconus screening indices. Masked expert reviewers subjectively graded images as normal, suspicious, or abnormal.
Results:
One hundred eyes of 50 patients were evaluated. The mean K values were not significantly different (anterior K: high resolution 1.21 diopters [D] ± 1.13 (SD) versus regular 1.15 ± 1.16 D, P = 0.73; posterior K: 0.34 ± 0.23 D versus regular 0.35 ± 0.23 D, P = .67). The mean CCT was significantly thinner in the high-resolution group (514.7 ± 26.6 μm versus 527.6 ± 27.6 μm (P < .0001) with limits of agreement of -12.9 to +17.5 μm. Most keratoconus screening indices were more suspicious with the high-resolution device than with the regular device except the indices of height asymmetry and height deviation. Subjectively, 60% of cases received the same score, high resolution was more suspicious in 28% of cases, and regular was more suspicious in 12% of cases; there was only slight subjective agreement between technologies (κ = 0.26 to 0.31).
Conclusions:
Regular and high-resolution Scheimpflug imaging devices generated different objective values and significantly different subjective interpretations with poor inter-reviewer agreement. The high-resolution device provided a more conservative overall output. For refractive surgical screening, the 2 devices are not interchangeable.
Financial Disclosure:
Proprietary or commercial disclosures are listed after the references.
