Journal of Peking University(Health Sciences) >
Examination and discriminant analysis of corneal biomechanics with CorVis ST in keratoconus and subclinical keratoconus
Received date: 2017-09-06
Online published: 2019-10-24
Supported by
Supported by the National Natural Science Foundation of China(11372011)
Objective: To compare the corneal biomechanical properties among keratoconus, subclinical keratoconus and normal corneas by using CorVis ST, and to estimate the effect of these biomechanical indices in discriminating keratoconus and subclinical keratoconus from normal. Methods: A total of 76 eyes of 67 subjects were enrolled and divided into three groups. Keratoconus group included 24 eyes from 17 patients, subclinical keratoconus group included 12 eyes from 12 patients and normal group included 40 normal eyes from 40 subjects.All the eyes were assessed with CorVis ST and ten biomechanical para-meters, intraocular pressure (IOP) and central corneal thickness (CCT) were obtained from this machine. The discrimination of biomechanical characteristic of the three groups based on the all indices was reflected by discriminant analysis and the Fisher discriminant function was established. Results: The values of corneal biomechanics of keratoconus, subclinical keratoconus, normal eyes were increased in sequence, except for three indices: the second applamation time (A2T), time taken to reach highest concavity (HCT) and maximum corneal velocity during the first applanation (Vin). Three sets of data were among a statistically significant difference (P<0.05). There were statistically significant differences (P<0.05) between any two groups by comparing with such two indices: radius value of central concave curvature at highest concavity (HCR) and CCT. The grades of the three groups were obvious, evaluated by the discriminant function. The accuracy of reevaluation was 85% by validation method. The biggest contribution of indices in discriminant function was given by such four indices in sequence: CCT, HCR, maximum deformation amplitude of highest concavity (HCDA) and maximum corneal velocity during the second applanation (Vout). Conclusion: The corneal biomechanical properties of keratoconus and subclinical keratoconus were decreased compared with normal eyes. The biomechanical parameters based on CorVis ST showed a good performance for discriminating among keratoconus, subclinical keratoconus and normal corneas.
Key words： Keratoconus; Biomechanics; Discrimination analysis
Yuan WU , Xiao-li LI , Song-lin YANG , Xiao-ming YAN , Hai-li LI . Examination and discriminant analysis of corneal biomechanics with CorVis ST in keratoconus and subclinical keratoconus[J]. Journal of Peking University(Health Sciences), 2019 , 51(5) : 881 -886 . DOI: 10.19723/j.issn.1671-167X.2019.05.015
| [1] | Gomes JA, Tan D, Rapuano CJ , et al. Global consensus on keratoconus and ectatic diseases[J]. Cornea, 2015,34(4):359-369. |
| [2] | Edmund C . Corneal elasticity and ocular rigidity in normal and keratoconic eyes[J]. Acta Ophthalmol (Copenh), 1988,66(2):134-140. |
| [3] | Labiris G, Giarmoukakis A, Gatzioufas Z , et al. Diagnostic capacity of the keratoconus match index and keratoconus match pro-bability in subclinical keratoconus[J]. J Cataract Refract Surg, 2014,40(6):999-1005. |
| [4] | Maguire LJ, Lowry JC . Identifying progression of subclinical keratoconus by serial topography analysis[J]. Am J Ophthalmol, 1991,112(1):41-45. |
| [5] | Rabinowitz YS . Keratoconus[J]. Surv Ophthalmol, 1998,42(4):297-319. |
| [6] | Tummanapalli SS, Potluri H, Vaddavalli PK , et al. Efficacy of axial and tangential corneal topography maps in detecting subclinical keratoconus[J]. J Cataract Refract Surg, 2015,41(10):2205-2214. |
| [7] | Hon Y, Lam AK . Corneal deformation measurement using Scheimpflug noncontact tonometry[J]. Optom Vis Sci, 2013,90(1):e1-e8. |
| [8] | Savini G, Barboni P, Carbonelli M , et al. Repeatability of automatic measurements by a new Scheimpflug camera combined with Placido topography[J]. J Cataract Refract Surg, 2011,37(10):1809-1816. |
| [9] | Holland DR, Maeda N, Hannush SB , et al. Unilateral keratoconus. Incidence and quantitative topographic analysis[J]. Ophthalmology, 1997,104(9):1409-1413. |
| [10] | Lee LR, Hirst LW, Readshaw G . Clinical detection of unilateral keratoconus[J]. Aust N Z J Ophthalmol, 1995,23(2):129-133. |
| [11] | Li X, Rabinowitz YS, Rasheed K , et al. Longitudinal study of the normal eyes in unilateral keratoconus patients[J]. Ophthalmology, 2004,111(3):440-446. |
| [12] | Saad A, Gatinel D . Subclinical keratoconus: the need for an objective classification system[J]. Ophthalmology, 2013,120(8):e56-e57. |
| [13] | Shirayama-Suzuki M, Amano S, Honda N , et al. Longitudinal analysis of corneal topography in suspected keratoconus[J]. Br J Ophthalmol, 2009,93(6):815-819. |
| [14] | Saad A, Gatinel D . Topographic and tomographic properties of forme fruste keratoconus corneas[J]. Invest Ophthalmol Vis Sci, 2010,51(11):5546-5555. |
| [15] | Baum J . On the location of the cone and the etiology of keratoconus[J]. Cornea, 1995,14(2):142-143. |
| [16] | Hassan Z, Modis L Jr, Szalai E , et al. Examination of ocular biomechanics with a new Scheimpflug technology after corneal refractive surgery[J]. Cont Lens Anterior Eye, 2014,37(5):337-341. |
| [17] | Bak-Nielsen S, Pedersen IB, Ivarsen A , et al. Dynamic Scheimpflug-based assessment of keratoconus and the effects of corneal cross-linking[J]. J Refract Surg, 2014,30(6):408-414. |
| [18] | Nemeth G, Hassan Z, Csutak A , et al. Repeatability of ocular biomechanical data measurements with a Scheimpflug-based noncontact device on normal corneas[J]. J Refract Surg, 2013,29(8):558-563. |
| [19] | Steinberg J, Katz T, Lucke K , et al. Screening for keratoconus with new dynamic biomechanical in vivo Scheimpflug analyses[J]. Cornea, 2015,34(11):1404-1412. |
/
| 〈 |
|
〉 |