Biomechanical Analysis of Subclinical Keratoconus With Normal Topographic, Topometric, and Tomographic Findings

Koç, Mustafa; Aydemır, Emre; Tekin, Kemal; İnanç, Merve; Kösekahya, Pınar; Kızıltoprak, Hasan

doi:10.3928/1081597x-20190226-01

Cited by 43 publications

(30 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our results in topometric indices showed conflicting information because almost all of the topometric indices except Rmin usually increase in keratoconic eyes 10. According to our results, KI and CKI statistically decreased, whereas ISV, IVA, IHA, IHD and Rmin statistically increased after the procedure.…”

Section: Discussioncontrasting

confidence: 62%

<p>Topometric Indices And Corneal Densitometry Change After Corneal Refractive Surgery Combined With Simultaneous Collagen Crosslinking</p>

Piyacomn

Kasetsuwan

Puangsricharern

et al. 2019

OPTH

View full text Add to dashboard Cite

PurposeTo show the alteration of tomography, topometric indices and corneal densitometry after corneal refractive surgery combined with collagen crosslinking.Patients and methodsAll medical records of patients undergoing corneal refractive surgery with simultaneous collagen crosslinking during April 2015 and August 2018 were retrospectively reviewed. Corneal tomography, higher-order aberrations (HOA), topographic indices and corneal densitometry were evaluated. All the data at 1 month, 3 months and 6 months were compared to baseline value. All complications were noted. P value less than 0.05 was considered statistically significant.ResultsMedical records of fourteen patients (twenty-five eyes) were reviewed. HOA increased at all time points (p < 0.05). Keratoconus index and central keratoconus index decreased, whereas index of surface variance, index of vertical asymmetry, index of height decentration and the minimum of radius of curvature increased at all time points (p < 0.05). Index of height asymmetry increased at 3 and 6 months (p < 0.05). Corneal densitometry at anterior layer of 0–10 mm zone and center layer of 0–6 mm zone increased at 1 and 3 months (p < 0.05). At 6 months, the densitometry at 0–6 mm zone returned to baseline level. However, at 6 months, at anterior and center layer of 6–10 mm zone, the densitometry values were still more than preoperative values (p < 0.05). There was one case of bacterial keratitis.ConclusionAfter the corneal refractive surgery combined with collagen crosslinking, the HOA and corneal densitometry increased. Topographic indices showed conflicting results.

show abstract

Section: Discussioncontrasting

confidence: 62%

<p>Topometric Indices And Corneal Densitometry Change After Corneal Refractive Surgery Combined With Simultaneous Collagen Crosslinking</p>

Piyacomn

Kasetsuwan

Puangsricharern

et al. 2019

OPTH

View full text Add to dashboard Cite

show abstract

“…Corneal biomechanical decompensation is considered to be a key trigger for collapse of the structural stability especially in eyes with post-LASIK ectasia [ 5 ]. It has been reported that alteration in corneal biomechanical parameters precedes the changes in corneal topography [ 6 – 8 ].…”

Section: Introductionmentioning

confidence: 99%

“…Thus far, corneal topography and corneal biomechanical analysis are the mainstream methods for diagnosis of corneal ectasia. An anterior segment analyser (Pentacam HR; Oculus Optikgeräte, Wetzlar, Germany) combined with a corneal biomechanical analyser (Corvis ST; Oculus Optikgeräte) demonstrated high sensitivity and specificity for early detection of both post-LASIK ectasia and primary keratoconus [ 8 – 11 ]. Biomechanical weakness has been reported in post-LASIK ectasia and primary keratoconus [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Corneal Biomechanical Properties between Post-LASIK Ectasia and Primary Keratoconus

Zhao

Shen

Jian

et al. 2020

Journal of Ophthalmology

View full text Add to dashboard Cite

Purpose. To compare the corneal biomechanical properties between post-LASIK ectasia and primary keratoconus. Methods. A total of 42 eyes of 42 patients with matching age and central corneal thickness (CCT) were divided into two groups according to diagnosis of post-LASIK ectasia (PLE group; n = 21; age range: 22–47 years) and primary keratoconus (KC group; n = 21; age range: 21–47 years). The corneal biomechanical properties were assessed using Scheimpflug-based technology (Corvis ST; Oculus Optikgeräte, Wetzlar, Germany). The paired t-test and linear regression analysis were performed. Results. The PLE group had significantly higher mean stiffness parameter at the first applanation (SP-A1; 76.65 ± 21.66 vs 52.72 ± 13.65, p ≤ 0.001 ) and mean stress-strain index (SSI) (SSI: 0.78 ± 0.16 versus 0.64 ± 0.12, p = 0.001 ) than the KC group. SP-A1 was positively correlated with CCT in the PLE group (Pearson’s r = 0.816, p ≤ 0.001 ), but not in the KC group (Pearson’s r = −0.014, p = 0.952 ). No statistical correlation was observed between SSI and CCT in either group (Pearson’s r = 0.292, p = 0.199 , and Pearson’s r = 0.004, p = 0.985 , respectively). Conclusions. In our case series, KC manifested more severe than PLE in biomechanical properties. Since SSI measurements were independent of corneal thickness, it can be used for corneal biomechanical assessment.

show abstract

“…Our results indicated that the Scheimp ug-derived morphological and biomechanical examinations were very useful to accurately distinguish normal from abnormal corneas (including both clinical and potential ectatic eyes). Previous studies using these measuring instruments reported similar outcomes that the combined parameters, especially TBI, was more effective [17][18][19][20]24] . In this study, we found that TBI had the highest diagnostic capacity in detecting corneal ectasia (AUC 0.966, Youden index 0.872), in accordance with many previous studies which found TBI was very accurate and valuable index to detect ectasia with high sensitivity and speci city in European, Middle East, South American, even…”

Section: Discussionmentioning

confidence: 64%

“…Considering that previous studies mostly focused on non-Chinese population [16][17][18][19][20] , the purpose of the current study is to evaluate the accuracy of KC and subclinical KC detection in Chinese patients by comparing the morphological and biomechanical parameters between frank KC, subclinical KC (FFKC) and normal eyes.…”

Section: Introductionmentioning

confidence: 99%

Application of Scheimpflug-Based Biomechanical Analyzer and Tomography in Early Detecting of Subclinical Keratoconus in Chinese Patients

Liu

Chen

2020

Preprint

View full text Add to dashboard Cite

PurposeTo evaluate the value of Scheimpflug-based biomechanical analyzer combined with tomography in detecting early keratoconus by distinguishing normal eyes from frank keratoconus (KC) and forme frusta keratoconus (FFKC) eyes in Chinese patients. MethodsThis study included 31 bilateral frank keratoconus patients, 27 unilateral clinical manifest keratoconus patients with very asymmetric eyes, and 79 control subjects with normal corneas. Corneal morphological and biomechanical parameters were measured using the Pentacam HR and Corvis ST (OCULUS, Wetzlar, Germany). The diagnostic capacity of computed parameters reflecting corneal biomechanical and morphological traits [including Belin-Ambrósio deviation index (BAD_D), Corvis biomechanical index (CBI) and tomographic and biomechanical index (TBI)] was determined using receiver operating characteristic (ROC) curves and compared by DeLong test. Additionally, the area under the curve (AUC), the best cutoff values, and Youden index for each parameter were reported. The novel corneal stiffness parameter (Stress-Strain Index or SSI) was also compared between KC, FFKC and normal eyes.ResultsEvery morphological and biomechanical index analyzed in this study was significantly different between KC, FFKC and normal eyes (p=0.000). TBI was most valuable for detecting subclinical keratoconus (FFKC eyes) with an AUC of 0.928 (P=0.000), and any forms of corneal ectasia (FFKC and frank KC eyes) with an AUC of 0.966 (P=0.000). The sensitivity and specificity of TBI for detecting FFKC was 97.5% and 77.8%, for detecting any KC was 97.5% and 89.7%, with a cut-off value of 0.375. Morphological index BAD_D and biomechanical index CBI were also very useful in distinguishing any KC eyes from normal eyes with an AUC of 0.965 and 0.934, respectively. SSI was significantly different between KC, FFKC and normal eyes (P=0.000), indicating an independent decrease in corneal stiffness in KC eyes.Conclusion Combination of Scheimpflug-based biomechanical analyzer and tomography could increase the accuracy of detecting early keratoconus in Chinese patients. TBI was the most valuable index for detecting subclinical keratoconus with high sensitivity and specificity. Evaluation of corneal biomechanical property in refractive surgery candidates is helpful to recognize potential keratoconic eyes and increase surgical safety.

show abstract

Biomechanical Analysis of Subclinical Keratoconus With Normal Topographic, Topometric, and Tomographic Findings

Cited by 43 publications

References 22 publications

<p>Topometric Indices And Corneal Densitometry Change After Corneal Refractive Surgery Combined With Simultaneous Collagen Crosslinking</p>

<p>Topometric Indices And Corneal Densitometry Change After Corneal Refractive Surgery Combined With Simultaneous Collagen Crosslinking</p>

Comparison of Corneal Biomechanical Properties between Post-LASIK Ectasia and Primary Keratoconus

Application of Scheimpflug-Based Biomechanical Analyzer and Tomography in Early Detecting of Subclinical Keratoconus in Chinese Patients

Contact Info

Product

Resources

About