The effect of corneal crosslinking on the rigidity of the cornea estimated using a modified algorithm for the Schiøtz tonometer
Purpose: The aim of this study was to test a method for estimating corneal rigidity before and after cross-linking (CXL) using a Schiøtz tonometer. Methods: The study was performed in the Kyiv City Clinical Ophthalmological Hospital “Eye Microsurgical Center”, Ukraine. This was a prospective, consec...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Wolters Kluwer Medknow Publications
2021-01-01
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| Series: | Indian Journal of Ophthalmology |
| Subjects: | |
| Online Access: | http://www.ijo.in/article.asp?issn=0301-4738;year=2021;volume=69;issue=6;spage=1531;epage=1536;aulast=Tutchenko |
| _version_ | 1818621587743571968 |
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| author | Larysa Tutchenko Sudi Patel Mykhailo Skovron Olha Horak Oleksiy Voytsekhivskyy |
| author_facet | Larysa Tutchenko Sudi Patel Mykhailo Skovron Olha Horak Oleksiy Voytsekhivskyy |
| author_sort | Larysa Tutchenko |
| collection | DOAJ |
| description | Purpose: The aim of this study was to test a method for estimating corneal rigidity before and after cross-linking (CXL) using a Schiøtz tonometer. Methods: The study was performed in the Kyiv City Clinical Ophthalmological Hospital “Eye Microsurgical Center”, Ukraine. This was a prospective, consecutive, randomized, masked, case-by-case, clinical study. Corneal rigidity, indicated by the gradient (G) between lg applied weight and corresponding lg scale reading during Schiøtz tonometry, were obtained by increasing (A-mode) then reducing (D-mode) weights by two operators [A] in keratoconus, post-CXL and control subjects for estimation of (i) interoperator and (ii) intersessional errors, (iii) intergroup differences; [B] before and after CXL. Central corneal thickness CCT was measured by scanning slit pachymetry. ANOVA, t tests, linear regression were the statistical tools used. Results: Average interoperator difference (ΔG) was –0.120 (SD = ±0.294, 95%CI = –0.175 to –0.066). A significant correlation between ΔG and the mean of each pair of G values was found (r = –0.196, n = 112, P = 0.038). Intersessional differences in mean G values were insignificant (P > 0.05). There was a significant correlation between G at first session (X1) and difference between sessions (ΔG) [Operator 1, ΔG = 0.598x1–0.461, r = 0.601, n = 27, P = 0.009]. Significant intergroup differences in G were found (Operator 1, one-way ANOVA, F = 4.489, P = 0.014). The difference (Δ) between the pre-(X2) and post-CXL treatment G values was significantly associated with the pre-CXL treatment value (Operator 1, Δ = 1.970x2-1.622, r = 0.642, n = 18, P = <.001). G values were correlated with CCT in keratoconus and post-CXL. Conclusion: Corneal rigidity (G) estimated using the Schiøtz tonometer can be useful for detecting changes after CXL. However, G values are linked to CCT, can vary from time-to-time and the procedure is operator dependent. |
| first_indexed | 2024-12-16T18:11:39Z |
| format | Article |
| id | doaj.art-35f91dabb9574861815f1709e61f49e6 |
| institution | Directory Open Access Journal |
| issn | 0301-4738 1998-3689 |
| language | English |
| last_indexed | 2024-12-16T18:11:39Z |
| publishDate | 2021-01-01 |
| publisher | Wolters Kluwer Medknow Publications |
| record_format | Article |
| series | Indian Journal of Ophthalmology |
| spelling | doaj.art-35f91dabb9574861815f1709e61f49e62022-12-21T22:21:45ZengWolters Kluwer Medknow PublicationsIndian Journal of Ophthalmology0301-47381998-36892021-01-016961531153610.4103/ijo.IJO_1820_20The effect of corneal crosslinking on the rigidity of the cornea estimated using a modified algorithm for the Schiøtz tonometerLarysa TutchenkoSudi PatelMykhailo SkovronOlha HorakOleksiy VoytsekhivskyyPurpose: The aim of this study was to test a method for estimating corneal rigidity before and after cross-linking (CXL) using a Schiøtz tonometer. Methods: The study was performed in the Kyiv City Clinical Ophthalmological Hospital “Eye Microsurgical Center”, Ukraine. This was a prospective, consecutive, randomized, masked, case-by-case, clinical study. Corneal rigidity, indicated by the gradient (G) between lg applied weight and corresponding lg scale reading during Schiøtz tonometry, were obtained by increasing (A-mode) then reducing (D-mode) weights by two operators [A] in keratoconus, post-CXL and control subjects for estimation of (i) interoperator and (ii) intersessional errors, (iii) intergroup differences; [B] before and after CXL. Central corneal thickness CCT was measured by scanning slit pachymetry. ANOVA, t tests, linear regression were the statistical tools used. Results: Average interoperator difference (ΔG) was –0.120 (SD = ±0.294, 95%CI = –0.175 to –0.066). A significant correlation between ΔG and the mean of each pair of G values was found (r = –0.196, n = 112, P = 0.038). Intersessional differences in mean G values were insignificant (P > 0.05). There was a significant correlation between G at first session (X1) and difference between sessions (ΔG) [Operator 1, ΔG = 0.598x1–0.461, r = 0.601, n = 27, P = 0.009]. Significant intergroup differences in G were found (Operator 1, one-way ANOVA, F = 4.489, P = 0.014). The difference (Δ) between the pre-(X2) and post-CXL treatment G values was significantly associated with the pre-CXL treatment value (Operator 1, Δ = 1.970x2-1.622, r = 0.642, n = 18, P = <.001). G values were correlated with CCT in keratoconus and post-CXL. Conclusion: Corneal rigidity (G) estimated using the Schiøtz tonometer can be useful for detecting changes after CXL. However, G values are linked to CCT, can vary from time-to-time and the procedure is operator dependent.http://www.ijo.in/article.asp?issn=0301-4738;year=2021;volume=69;issue=6;spage=1531;epage=1536;aulast=Tutchenkocorneacxlrigidityschiøtz tonometer |
| spellingShingle | Larysa Tutchenko Sudi Patel Mykhailo Skovron Olha Horak Oleksiy Voytsekhivskyy The effect of corneal crosslinking on the rigidity of the cornea estimated using a modified algorithm for the Schiøtz tonometer Indian Journal of Ophthalmology cornea cxl rigidity schiøtz tonometer |
| title | The effect of corneal crosslinking on the rigidity of the cornea estimated using a modified algorithm for the Schiøtz tonometer |
| title_full | The effect of corneal crosslinking on the rigidity of the cornea estimated using a modified algorithm for the Schiøtz tonometer |
| title_fullStr | The effect of corneal crosslinking on the rigidity of the cornea estimated using a modified algorithm for the Schiøtz tonometer |
| title_full_unstemmed | The effect of corneal crosslinking on the rigidity of the cornea estimated using a modified algorithm for the Schiøtz tonometer |
| title_short | The effect of corneal crosslinking on the rigidity of the cornea estimated using a modified algorithm for the Schiøtz tonometer |
| title_sort | effect of corneal crosslinking on the rigidity of the cornea estimated using a modified algorithm for the schiotz tonometer |
| topic | cornea cxl rigidity schiøtz tonometer |
| url | http://www.ijo.in/article.asp?issn=0301-4738;year=2021;volume=69;issue=6;spage=1531;epage=1536;aulast=Tutchenko |
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