Comparative evaluation of progression rate in keratoconus before and after collagen crosslinking

Posted Posted in cornea

progression, keratoconus, collagen, crosslinking

2017 Nov 9. pii: bjophthalmol-2017-311017. doi: 10.1136/bjophthalmol-2017-311017. [Epub ahead of print]

Comparative evaluation of progression rate in keratoconus before and after collagen crosslinking.

Abstract

PURPOSE:

To compare the rate of disease progression in keratoconus before and after corneal collagen crosslinking (CXL).

METHODS:

145 eyes were followed without CXL (no-CXL group) for a median duration of 31 months whereas 45 eyes were followed up for 41 months before (pre-CXL) and after (post-CXL) accelerated, epithelium-off crosslinking. Progression was defined based on significant slope found in linear mixed effect models against time. Swept-source optical coherence tomography was used for measurement of anterior steep keratometry, anterior flat keratometry (Ant Kf), anterior average keratometry (Ant Avg K); posterior steep keratometry, posteriorflat keratometry (Post Kf), posterior average keratometry (Post Avg K) and corneal thickness.

RESULTS:

The patients in pre-CXL group were significantly younger (26.3±5.48 years) compared with the patients in no-CXL group (32.7±10.24 years) (P=0.004). Significant differences were observed during baseline examination for all parameters (P≤0.035) between pre-CXL and no-CXL groups except Ant Cyl and Post Cyl. During observation period, statistically significant differences were noted between pre-CXL and no-CXL groups in the progression rate of Ant Kf, Ant Avg K, Post Kf and Post Avg K (P≤0.045). After CXL, the progression rate in post-CXL group was comparable to that in no-CXL group. All corneal parameters remained stable in no-CXL group throughout the follow-up period.

CONCLUSIONS:

Serial tomographic examination is useful to document disease progression before and after CXL. In our study, a decrease in progression rate of corneal parameters was noted after CXL. In cases with stable corneal parameters over time, careful monitoring can be considered instead of collagen crosslinking.

progression, keratoconus, collagen, crosslinking:

cornea; imaging; treatment other

PMID:
29122823
DOI:
10.1136/bjophthalmol-2017-311017

Tear biomarkers for keratoconus.

Posted Posted in cornea
Biomarkers, Keratoconus, Metabolites, Proteins, Tears
Eye Vis (Lond). 2016 Aug 4;3:19. doi: 10.1186/s40662-016-0051-9. eCollection 2016.

Tear biomarkers for keratoconus.

Author information

 Biomarkers, Keratoconus, Metabolites, Proteins, Tears

Abstract

Keratoconus is a progressive corneal thinning, ectatic condition, which affects vision. Recent advances in corneal topography measurements has helped advance proper diagnosis of this condition and increased research and clinical interests in the disease etiopathogenesis. Considerable progress has been achieved in understanding the progression of the disease and tear fluid has played a major role in the progress. This review discusses the importance of tear fluid as a source of biomarker for keratoconus and how advances in technology have helped map the complexity of tears and thereby molecular readouts of the disease. Expanding knowledge of the tear proteome, lipidome and metabolome opened up new avenues to study keratoconus and to identify probable prognostic or diagnostic biomarkers for the disease. A multidimensional approach of analyzing tear fluid of patients layering on proteomics, lipidomics and metabolomics is necessary in effectively decoding keratoconus and thereby identifying targets for its treatment.

KEYWORDS:

Biomarkers; Keratoconus; Metabolites; Proteins; Tears

Abstract

Keratoconus is a progressive corneal thinning, ectatic condition, which affects vision. Recent advances in corneal topography measurements has helped advance proper diagnosis of this condition and increased research and clinical interests in the disease etiopathogenesis. Considerable progress has been achieved in understanding the progression of the disease and tear fluid has played a major role in the progress. This review discusses the importance of tear fluid as a source of biomarker for keratoconus and how advances in technology have helped map the complexity of tears and thereby molecular readouts of the disease. Expanding knowledge of the tear proteome, lipidome and metabolome opened up new avenues to study keratoconus and to identify probable prognostic or diagnostic biomarkers for the disease. A multidimensional approach of analyzing tear fluid of patients layering on proteomics, lipidomics and metabolomics is necessary in effectively decoding keratoconus and thereby identifying targets for its treatment.

KEYWORDS:

Biomarkers; Keratoconus; Metabolites; Proteins; Tears

Keratoconus: The ABCD Grading System.

Posted Posted in cornea
Keratoconus, Grading System, astigmatism, aberration, ABCD grading
Klin Monbl Augenheilkd. 2016 Jan 20. [Epub ahead of print]

Keratoconus: The ABCD Grading System.

Abstract

Purpose: To propose a new keratoconus classification/staging system that utilises current tomographic data and better reflects the anatomical and functional changes seen in keratoconus. Method: A previously published normative database was reanalysed to generate both anterior and posterior average radii of curvature (ARC and PRC) taken from a 3.0 mm optical zone centred on the thinnest point of the cornea. Mean and standard deviations were recorded and anterior data were compared to the existing Amsler-Krumeich (AK) Classification. ARC, PRC, thinnest pachymetry and distance visual acuity were then used to construct a keratoconus classification. Results: 672 eyes of 336 patients were analysed. Anterior and posterior values were 7.65 ± 0.236 mm and 6.26 ± 0.214 mm, respectively, and thinnest pachymetry values were 534.2 ± 30.36 µm. The ARC values were 2.63, 5.47 and 6.44 standard deviations from the mean values of stages 1-3 in the AK classification, respectively. PRC staging uses the same standard deviation gates. The pachymetric values differed by 4.42 and 7.72 standard deviations for stages 2 and 3, respectively. Conclusion: A new keratoconus staging incorporates anterior and posterior curvature, thinnest pachymetric values, and distance visual acuity and consists of stages 0-4 (5 stages). The proposed system closely matches the existing AK classification stages 1-4 on anterior curvature. As it incorporates posterior curvature and thickness measurements based on the thinnest point, rather than apical measurements, the new staging system better reflects the anatomical changes seen in keratoconus.

Results: 672 eyes of 336 patients were analysed. Anterior and posterior values were 7.65 ± 0.236 mm and 6.26 ± 0.214 mm, respectively, and thinnest pachymetry values were 534.2 ± 30.36 µm. The ARC values were 2.63, 5.47 and 6.44 standard deviations from the mean values of stages 1-3 in the AK classification, respectively. PRC staging uses the same standard deviation gates. The pachymetric values differed by 4.42 and 7.72 standard deviations for stages 2 and 3, respectively. Conclusion: A new keratoconus staging incorporates anterior and posterior curvature, thinnest pachymetric values, and distance visual acuity and consists of stages 0-4 (5 stages). The proposed system closely matches the existing AK classification stages 1-4 on anterior curvature. As it incorporates posterior curvature and thickness measurements based on the thinnest point, rather than apical measurements, the new staging system better reflects the anatomical changes seen in keratoconus.

An analysis of factors influencing quality of vision after big-bubble deep anterior lamellar keratoplasty in keratoconus.

Posted Posted in cornea
Am J Ophthalmol. 2015 Nov 14. pii: S0002-9394(15)00706-0. doi: 10.1016/j.ajo.2015.11.018. [Epub ahead of print]

An analysis of factors influencing quality of vision after big-bubble deep anterior lamellar keratoplasty in keratoconus.

Abstract

PURPOSE:

To identify causes of reduced visual acuity and contrast sensitivity after big-bubble deep anterior lamellar keratoplasty (DALK) in keratoconus.

DESIGN:

Prospective interventional case series.

METHODS:

This study included 36 eyes in 36 patients with keratoconus who underwent DALK using the big-bubble technique. A bare Descemet membrane was achieved in all cases. Univariate analyses and multiple linear regression were used to investigate recipient-, donor-, and postoperative-related variables capable of influencing the postoperative quality of vision, including best-spectacle corrected visual acuity (BSCVA) and contrast sensitivity.

RESULTS:

The mean patient age was 27.7±6.9 years old, and the patients were followed for 24.6±15.1 months postoperatively. The mean postoperative BSCVA was 0.17±0.09 LogMAR. Postoperative BSCVA ≥ 20/25 was achieved in 14 eyes (38.9%), whereas a BSCVA of 20/30, 20/40, or 20/50 was observed in 15 eyes (41.7%), six eyes (16.6%), and one eye (2.8%), respectively. Preoperative vitreous length was significantly associated with postoperative BSCVA (β=0.02, P=0.03). Donor-recipient interface reflectivity significantly influenced scotopic (β=-0.002, P=0.04) and photopic (β=-0.003, P=0.02) contrast sensitivity. The root mean square of tetrafoil was significantly negatively associated with scotopic (β=-0.25, P=0.01) and photopic (β=-0.23, P=0.04) contrast sensitivity. Recipient age, keratoconus severity, donor-related variables, recipient trephination size, and graft and recipient bed thickness were not significantly associated with postoperative visual acuity or contrast sensitivity.

CONCLUSION:

Large vitreous length, higher-order aberrations, and surgical interface haze may contribute to poor visual outcomes after big-bubble DALK in keratoconus.

RESULTS:

The mean patient age was 27.7±6.9 years old, and the patients were followed for 24.6±15.1 months postoperatively. The mean postoperative BSCVA was 0.17±0.09 LogMAR. Postoperative BSCVA ≥ 20/25 was achieved in 14 eyes (38.9%), whereas a BSCVA of 20/30, 20/40, or 20/50 was observed in 15 eyes (41.7%), six eyes (16.6%), and one eye (2.8%), respectively. Preoperative vitreous length was significantly associated with postoperative BSCVA (β=0.02, P=0.03). Donor-recipient interface reflectivity significantly influenced scotopic (β=-0.002, P=0.04) and photopic (β=-0.003, P=0.02) contrast sensitivity. The root mean square of tetrafoil was significantly negatively associated with scotopic (β=-0.25, P=0.01) and photopic (β=-0.23, P=0.04) contrast sensitivity. Recipient age, keratoconus severity, donor-related variables, recipient trephination size, and graft and recipient bed thickness were not significantly associated with postoperative visual acuity or contrast sensitivity.

CONCLUSION:

Large vitreous length, higher-order aberrations, and surgical interface haze may contribute to poor visual outcomes after big-bubble DALK in keratoconus.

Copyright © 2015 Elsevier Inc. All rights reserved.