The elasticity and rigidity of the outer coats of the eye

Asejczyk-Widlicka, Magdalena; Pierscionek, Barbara K.

doi:10.1136/bjo.2008.140178

Cited by 66 publications

(62 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In other research, porcine corneas within the physiologic range of intraocular pressures (12-25 mm Hg) have shown negligible changes in corneal curvature or surface distention. 54 Even with a uniform excimer ablation and 70% of the corneal thickness remaining, we have seen no significant changes in curvature or surface expansion, which agrees with the prior study. These findings provide evidence that the asphericity induced with excimer ablation is not related to a mechanical weakening of the central cornea.…”

Section: Discussionsupporting

confidence: 82%

Corneal Surface Asphericity, Roughness, and Transverse Contraction after Uniform Scanning Excimer Laser Ablation

McCafferty

Schwiegerling

Enikov

2012

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

PURPOSE.To examine the interaction between the excimer laser and residual tissue. METHODS. Ten cadaveric porcine eyes with exposed corneal stroma and plastic test spheres underwent uniform 6-mm ablation with a scanning excimer laser. Corneal profilometry of the central 3 mm was measured with submicrometer resolution optical interferometry, before and after uniform excimer ablation. Eleven surface-marked eyes were photomicrographed before and after excimer ablation. Images were superimposed, and mark positional changes were measured. RESULTS. Uniform scanning excimer laser ablation of the corneal stroma produces a significant central steepening and peripheral flattening in the central 3-mm of the diameter. The central 1-mm corneal curvature radius (r) decreased from r ϭ 10.07 Ϯ 0.44 (95% CI) to 7.22 Ϯ 0.30 mm, and the central 2-mm radius decreased from r ϭ 10.16 Ϯ 0.44 to 8.10 Ϯ 0.43 mm. Q values, measuring asphericity in the 2-mm radius of the central cornea, were significantly lower before than after ablation (Ϫ5.03 Ϯ 4.01 vs. Ϫ52.4 Ϯ 18.7). Surface roughness increased significantly from 0.65 Ϯ 0.06 to 1.75 Ϯ 0.32 m after ablation. The central 2 mm of the stromal surface contracted by 2.21% Ϯ 0.80% at a sustained temperature of 5°C. Ablation of plastic spheres produced no significant change. CONCLUSIONS. The excimer laser interacts with the nonablated residual stromal surface in a characteristic fashion not seen with isotropic, inorganic material. Increases in asphericity, surface roughness, surface contraction, and stromal morphologic changes are supportive of this interaction. The surface changes demonstrated may be indicative of temperature-induced transverse collagen fibril contraction and stress redistribution, or the ablation threshold of the stromal surface may be altered. This phenomenon may be of increased importance using lasers with increased thermal load. (Invest Ophthalmol Vis Sci.

show abstract

Section: Discussionsupporting

confidence: 82%

Corneal Surface Asphericity, Roughness, and Transverse Contraction after Uniform Scanning Excimer Laser Ablation

McCafferty

Schwiegerling

Enikov

2012

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

show abstract

“…There are a number of previous reports of measurements of the mechanical properties of the sclera (Battaglioli and Kamm, 1984;Downs and Suh et al, 2003;Asejczyk-Widlicka and Pierscionek, 2008;Schultz and Lotz et al, 2008). From these various experiments the elastic moduli appear to be of the order of 500 kPa although the data cover a wide range of values, techniques and uncertainties.…”

Section: Introductionmentioning

confidence: 80%

Surface characterisation and biomechanical analysis of the sclera by atomic force microscopy

Grant

Thomson

Savage

et al. 2011

Journal of the Mechanical Behavior of Biomedical Materials

View full text Add to dashboard Cite

“…22,23 However, DCT tips are accurate at specified radii of curvature and therefore would not work on the sclera, which has a radius of curvature that varies significantly with IOP. 24,25 Additionally, even if the scleral radius of curvature does not vary with changes in IOP, the larger radius of curvature of the sclera would require the use of DCT tips that produce large deviations and are considered inaccurate. 2 Our study has several limitations.…”

Section: Discussionmentioning

confidence: 98%

Correlation Between Corneal and Scleral Pneumatonometry: An Alternative Method for Intraocular Pressure Measurement

Kapamajian¹,

Cruz²,

Hallak³

et al. 2013

American Journal of Ophthalmology

View full text Add to dashboard Cite

The elasticity and rigidity of the outer coats of the eye

Cited by 66 publications

References 17 publications

Corneal Surface Asphericity, Roughness, and Transverse Contraction after Uniform Scanning Excimer Laser Ablation

Corneal Surface Asphericity, Roughness, and Transverse Contraction after Uniform Scanning Excimer Laser Ablation

Surface characterisation and biomechanical analysis of the sclera by atomic force microscopy

Correlation Between Corneal and Scleral Pneumatonometry: An Alternative Method for Intraocular Pressure Measurement

Contact Info

Product

Resources

About