Corneal collagen crosslinking using riboflavin and ultraviolet-A light for keratoconus

Grewal, Dilraj S.; Brar, Gagandeep; Jain, Rajeev; Sood, Vardaan; Singla, Mohit; Grewal, Satinder Pal Singh

doi:10.1016/j.jcrs.2008.11.046

Cited by 171 publications

(146 citation statements)

References 33 publications

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“…Our findings show that the lower resistance to deformation in keratoconus group is not due only to thinning, because the groups were matched by thickness. Additionally, higher corneal resistance after collagen cross-linking is often accompanied by thinning (28)(29) . Therefore, corneal rigidity and resistance to deformation are likely affected by unknown factors in addition to corneal thickness (12) .…”

Section: Discussionmentioning

confidence: 99%

Corneal biomechanical evaluation in healthy thin corneas compared with matched keratoconus cases

Fontes¹,

Ambrósio²,

Velarde³

et al. 2011

Arq. Bras. Oftalmol.

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Purpose: To evaluate and compare corneal hysteresis (CH) and corneal resistance factor (CRF) in healthy eyes with a central corneal thickness (CCT) ≤ 505 μm with CH and CRF in gender-, age-, and CCT-matched keratoconus cases, and to estimate the sensitivity and specificity of these parameters for discriminating between the two groups. Methods: Prospective, comparative case series. In total 46 eyes from 30 healthy patients with CCT ≤ 505 μm, and 42 eyes from 30 CCT-, gender-and age-matched keratoconus cases were enrolled. Biomechanical metrics (CH and CRF) were measured using the Ocular Response Analyzer (ORA) and then compared. A receiver operating characteristic (ROC) curve was used to identify cut-off points to maximize the sensitivity and specificity for discriminating between the groups. Results: The CCT was 485.96 ± 17.61 μm (range, 438 -505) in healthy thin corneas and 483.64 ± 16.19 μm (range, 452 -505) in keratoconus; p=0.5225. CH was 8.63 ± 1.23 mmHg (range, 5.95 -12.2) and 8.07 ± 1.17 mmHg (range, 4.9 -9.85), respectively; p=0.0312. CRF was 8.43 ± 1.29 mmHg (range, 5.45 -11.10) and 7.22 ± 1.34 mmHg (range, 4.7 -9.45), respectively; p<0.001. ROC curve analysis showed a poor overall predictive accuracy of CH (cut-off, 8.95 mmHg; sensitivity, 63%; specificity, 23.8%; test accuracy, 44.30%) and CRF (cut-off, 7.4 mmHg; sensitivity, 28.3%; specificity, 40.5%; test accuracy, 34.12%) for detecting keratoconus in the eyes studied. Conclusion: CH and CRF were statistically lower in keratoconus than in healthy thin corneas. However, CH and CRF offered very low sensitivity and specificity for discriminating the groups.Keywords: Cornea/physiology; Keratoconus; Corneal diseases; Biomechanics/physiology; Diagnostic techniques, ophthalmological RESUMOObjetivo: Avaliar e comparar a histerese corneana (CH) e o fator de resistência corneano (CRF) em olhos saudáveis com espessura corneana central (CCT) ≤ 505 μm com os resultados de CH e CRF em pacientes com ceratocone pareados por sexo, idade e CCT, além de estimar a sensibilidade e especificidade destes parâmetros na diferenciação dos grupos. Métodos: Estudo prospectivo, do tipo série de casos comparativa. No total, 46 olhos de 30 pacientes saudáveis com CCT ≤ 505 μm, e 42 olhos de 30 pacientes com ceratocone pareados por sexo, idade e CCT foram incluídos. Os parâmetros biomecânicos (CH e CRF) foram obtidos através do equipamento Ocular Response Analyzer (ORA) e depois comparados. Curvas ROC (Receiver operating characteristic) foram utilizadas para identificar o melhor valor de corte que apresentasse a maior sensibilidade e especificidade na discriminação entre ceratocone e córneas finas saudáveis para cada dado estudado. Resultados: A CCT encontrada foi 485,96 ± 17,61 μm (de 438 a 505) no grupo de córneas finas saudáveis e 483.64 ± 16,19 μm (de 452 a 505) no grupo ceratocone; p=0,5225. CH 8,63 ± 1,23 mmHg (de 5,95 a 12,2) e 8,07 ± 1,17 mmHg (de 4,9 a 9,85), respectivamente; p=0,0312. CRF 8,43 ± 1,29 mmHg (de 5,45 a 11,10) e 7,22 ± 1,34 mmHg (de 4,7 a 9,45), resp...

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Section: Discussionmentioning

confidence: 99%

Corneal biomechanical evaluation in healthy thin corneas compared with matched keratoconus cases

Fontes¹,

Ambrósio²,

Velarde³

et al. 2011

Arq. Bras. Oftalmol.

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“…5,6,15 Numerous clinical studies agreed that CXL treatment provides significant improvements in visual acuity and maximum keratometry as well as halting the progression of keratoconus. 7,8,16,17 However, it is still unclear whether baseline demographic and topographic characteristics influence postoperative outcomes. Therefore, we sought effects of age, gender, preoperative CDVA, preoperative maximum K, topographic cone location, and preoperative thinnest corneal pachymetry on improvements in CDVA and maximum K at 1 year after CXL treatment.…”

Section: Eyementioning

confidence: 99%

Factors affecting outcomes of corneal collagen crosslinking treatment

Toprak

Yaylalı

Yıldırım

2013

Eye

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Purpose To assess the effects of preoperative patient characteristics on clinical outcomes of corneal crosslinking (CXL) treatment in patients with progressive keratoconus. Methods This retrospective study comprised 96 eyes of 96 patients who had unilateral CXL treatment for progressive keratoconus. All patients underwent a complete ophthalmological examination and corneal topography at baseline and 1 year. Subgroup analyses were performed according to the age (o30 andZ30 years), gender, preoperative corrected distance visual acuity (CDVA, o0.3 and Z0.3 logMAR (log of the minimum angle of resolution)), preoperative maximum keratometry (K, o54 and Z54 D), baseline topographic cone location (central, paracentral, and peripheral), and preoperative thinnest pachymetry (o450 and Z450 mm) to determine the associations between preoperative patient characteristics and outcomes (changes in visual acuity and maximum keratometry) of CXL treatment. Results In the entire study population, mean CDVA and maximum K significantly improved after CXL treatment (Po0.001). Patients with a preoperative CDVA of 20/40 Snellen equivalent or worse (Z0.3 logMAR) experienced more visual improvement after CXL treatment (Po0.001). However, an age Z30 years and a baseline thinnest pachymetry less than 450 mm were found significantly associated with more flattening in maximum keratometry (P ¼ 0.024, P ¼ 0.005 respectively). Gender, preoperative maximum K, and baseline topographic cone location did not show significant effect on postoperative visual acuity and maximum keratometry (P40.05). Conclusions In patients with progressive keratoconus, age, baseline visual acuity, and baseline thinnest pachymetry seem to affect the success of the CXL treatment.

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“…Specifically, K max became flatter by 0.58 ± 1.37 D (p = 0.02), which is similar to multiple other studies. 12,14,16,17,[21][22][23][24][25][26][27] The trend is for significant flattening of the central steeper curvature. Of interest, the peripheral keratometry measurements found the inferior and temporal cornea to become flatter, with superior and nasal cornea becoming steeper.…”

Section: Discussionmentioning

confidence: 97%

“…By comparison, Grewal et al found no change in central posterior curvature at one year. 21 Vinciguerra et al assessed the posterior surface using elevation maps and found no significant difference at one year. The central corneal pachymetry measurements were significantly thinner at 6 months, with a rebound to be similar readings at the one year mark compared to preoperative levels.…”

Section: Discussionmentioning

confidence: 99%

The Effects of Epithelium-off Corneal Collagen Cross-linking on Peripheral Corneal Keratometry, Pachymetry as well as Scheimpflug Imaging Calculated Corneal Indices in Keratoconus

Muzychuk¹,

Penner²,

Rocha³

et al. 2014

International Journal of Keratoconus and Ectatic Corneal Diseases

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Purpose: To utilize Scheimpflug imaging to describe corneal changes in keratoconic patients undergoing collagen crosslinking.Study type: Case series. Study design:Retrospective chart review at two sites: Calgary, Alberta and Brandon, Manitoba, Canada. All patients were diagnosed with keratoconus and had undergone corneal collagen crosslinking. All patients had pre-and post-procedure imaging done with Oculus Pentacam.Results: Sixty-one eyes of 48 patients with 6 months followup and 36 eyes of 27 patients with one year follow-up were included. Average age was 27 ± 12 years (15-48 years). Fiftyone males and 10 females were studied. At 1 year follow-up, all Pentacam indices were found to improve: ISV -4.44 ± 18.6 (p = 0.16), IVA -0.07 ± 0.27 (p = 0.12), KI -0.009 ± 0.082 (p = 0.49), CKI -0.012 ± 0.027 (p = 0.01), IHA -3.87 ± 23.3 (p = 0.33) and IDH -0.062 ± 0.308 (p = 0.24). Keratometry measurements were flatter at the pupil centre by 0.87 ± 2.53 D (p = 0.05). K max and K min were flatter by 0.58 ± 1.37 D (p = 0.02) and 0.33 ± 1.70 D (p = 0.25) respectively. Pupil center pachymetry was thinner by 12.9 ± 21.1 µm (p = 0.0006) at 6 months, as were the corneal apex and thinnest local by 12.9 ± 22.3 µm (p = 0.001) and 21.8 ± 54.6 µm (p = 0.05) respectively. However, all central pachymetry readings were not statistically different from baseline at the one year measurements. Peripheral corneal measurements at 6 mm diameter were no different from baseline at 6 months, however, were significantly thicker at the 1 year follow-up. Conclusion:The data, in this study, points to a more uniform cornea post corneal collagen crosslinking. The inferior cornea becomes flatter and superior cornea steeper with less variation when comparing the corneal curvatures. The peripheral cornea becomes thicker at 1 year post-procedure. Collagen crosslinking stabilizes the cornea.

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Corneal collagen crosslinking using riboflavin and ultraviolet-A light for keratoconus

Cited by 171 publications

References 33 publications

Corneal biomechanical evaluation in healthy thin corneas compared with matched keratoconus cases

Corneal biomechanical evaluation in healthy thin corneas compared with matched keratoconus cases

Factors affecting outcomes of corneal collagen crosslinking treatment

The Effects of Epithelium-off Corneal Collagen Cross-linking on Peripheral Corneal Keratometry, Pachymetry as well as Scheimpflug Imaging Calculated Corneal Indices in Keratoconus

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