How Abnormal Is the Noncorneal Biometry of Keratoconic Eyes?

Rozema, J.; Zakaria, Nadia; Hidalgo, I.; Jongenelen, Sien; Tassignon, Marie-José; Koppen, Carina

doi:10.1097/ico.0000000000000802

Cited by 8 publications

(8 citation statements)

References 35 publications

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“…18 In their study with KC patients, Rozema et al presented that the changes in VD and AL became significant when they removed ametropes from the control groups and left only the emmetropic eyes. 19 As in these studies that differentiate the control group from emmetropia, we measured AL as 24.94 ± 0.7 mm and 23.88 ± 0.96 mm, respectively, in the myopic group and KC group, and it was higher in favour of the myopic control group (p < 0.001). LT and VD were also higher in the myopic group.…”

Section: Discussionmentioning

confidence: 87%

Evaluation of ocular biometric parameters in keratoconic eyes relative to healthy myopic eyes

Kanra¹,

Uslu²

2021

European Journal of Ophthalmology

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Objective To assess the biometric features of keratoconic eyes using the Lenstar LS900 and Pentacam systems relative to healthy myopic eyes. Materials and Methods Seventy-three eyes of keratoconic subjects and 83 eyes of control subjects were enrolled. To evaluate the reproducibility of the Lenstar and Pentacam devices’ measurements, keratometric readings [in flattest meridian (Kf), in steepest meridian (Ks), and mean (Km)], central corneal thickness (CCT), and anterior chamber depth (ACD) were obtained using both systems. Axial length and lens thickness (LT) were measured by the Lenstar. The compatibility between the two devices was investigated using the Bland-Altman statistical method. Results Axial length was longer in the myopic group than in eyes with keratoconus (24.94 ± 0.7 and 23.88 ± 0.96 mm, respectively, p < 0.001). LT and vitreous depth were also higher in the myopic group, although ACD values were similar. Compared to the Lenstar, the Pentacam measured the ACD and CCT values higher in the myopia group [with a difference of 0.07 ± 0.12 mm ( p <0.001) and 4.47 ± 11.33 µm ( p = 0.001), respectively] and measured the CCT values higher in the keratoconus group. Pentacam found all keratometry values significantly lower than Lenstar in the keratoconus group. Conclusions Axial length was longer in the myopic eyes due to the differences starting from the lens and extending to the posterior segment. Lenstar and Pentacam can be used interchangeably for Km, Kf, and ACD in the myopic group and only for ACD in the keratoconus group.

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Section: Discussionmentioning

confidence: 87%

Evaluation of ocular biometric parameters in keratoconic eyes relative to healthy myopic eyes

Kanra¹,

Uslu²

2021

European Journal of Ophthalmology

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“…Thin steep cornea and high, often extreme, asymmetric irregular astigmatism are inherent features of keratoconus; keratoconic eyes tend to have deeper anterior chamber depth measurements and higher spherical aberrations and HOAs, including coma and trefoil. 9,10,12,23 Abnormal corneal topography of both the anterior and posterior surfaces of the cornea showing higher than normal and irregular astigmatism and axial myopia and deep anterior chamber values impact IOL power calculation in keratoconic eyes. 1 Using conventional lens power calculation formulas often results in a hyperopic refractive outcome.…”

Section: Discussionmentioning

confidence: 99%

“…4,5,7,8 Different IOL calculation formulas perform well in average eyes; however, biometric values in eyes with keratoconus not only are characterized by extreme steep anterior keratometry readings with asymmetric irregular high astigmatism but also present with long axial length, steep posterior corneal power and curvature, thin central corneal thickness, and deep anterior chamber. [8][9][10][11][12] These measurements affect the estimated effective lens position (ELP) and may compromise the prediction of postoperative refraction in eyes with unusual ocular parameters. 4 Holladay and Kane have recommended specific modifications within their formulas for IOL power calculation in keratoconus.…”

mentioning

confidence: 99%

Toric intraocular lens power calculation in cataract patients with keratoconus

Ton

Barrett

Kleinmann

et al. 2021

J Cataract Refract Surg

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“…lens asphericity, that are difficult to obtain directly in a clinical setting. Given that it was recently demonstrated that keratoconic eyes only differ from normal eyes in their corneal shapes and anterior chamber depth, using lens parameters from a healthy eye model should not introduce any substantial errors. Once filled in, the model can be used to calculate the associated wavefronts, as well as the refraction in the form of spherical equivalent S.E., and Jackson power vectors J 0 and J 45 .…”

Section: Methodsmentioning

confidence: 99%