Corneal Asphericity and Apical Curvature in Children: A Cross-sectional and Longitudinal Evaluation

Davis, William R.; Raasch, Thomas W.; Mitchell, G. Lynn; Mutti, Donald O.; Zadnik, Karla

doi:10.1167/iovs.04-0558

Cited by 61 publications

(68 citation statements)

References 33 publications

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“…[11][12][13] Currently, the most commonly accepted value in a young adult population is approximately -0.23 ± 0.08. 14 As the asphericity can be considered as one of markers of quality of vision, 15 turning it closer to normal or at least reducing the excess of prolateness usually found in keratoconus, could be a predictor of improvement of vision.…”

Section: Discussionmentioning

confidence: 99%

Correlation of Anterior Segment Parameters in Keratoconus Patients

Torquetti¹,

Ferrara²,

Ferrara³

et al. 2012

International Journal of Keratoconus and Ectatic Corneal Diseases

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Purpose: To evaluate the corneal asphericity, volume, thickness and keratometry and the correlation among these variables in keratoconus patients. Materials and methods:A total of 1,071 eyes of 810 patients diagnosed with keratoconus were evaluated with a Pentacam (Oculus Optikgerate GmbH). Results: Sixty-six eyes had very mild keratoconus, 269 had mild keratoconus, 465 had moderate keratoconus, 233 had severe keratoconus and 38 had very severe keratoconus. As the severity of disease increases, there is an increment in K and CV values and reduction of Q and TCT. There was a statistically significant difference in values for all parameters, except the CV. The Pearson correlation index showed an inverse correlation between the degree of keratoconus and the asphericity (Q), i.e. the more severe the keratoconus the more negative the Q-value. Only in the very severe group there was no statistically significant correlation between K and Q. There was no correlation between severity of keratoconus and CV. There was an inverse correlation between keratoconus grade and TCT; the more advanced the disease the less the TCT value. Only in the very mild group there was no correlation between K and TCT. Conclusion:The corneal asphericity and pachymetry are inversely correlated to keratometry in keratoconus patients. There is no correlation between CV and severity of keratoconus.

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Section: Discussionmentioning

confidence: 99%

Correlation of Anterior Segment Parameters in Keratoconus Patients

Torquetti¹,

Ferrara²,

Ferrara³

et al. 2012

International Journal of Keratoconus and Ectatic Corneal Diseases

View full text Add to dashboard Cite

show abstract

“…It should be considered that the geometry of the anterior corneal surface of the human cornea can be adjusted to a conical section that is characterized by an asphericity (Q) and a specific value for the radius of the apical curvature (r 0 ). 41,42 The Q characterizes the gradual curvature change in the corneal surface from center to periphery. [42][43][44] The most commonly accepted value for Q in young adult patients is À0.23 G 0.08 (prolate ellipsoid).…”

Section: Corneal Asphericitymentioning

confidence: 99%

“…41,42 The Q characterizes the gradual curvature change in the corneal surface from center to periphery. [42][43][44] The most commonly accepted value for Q in young adult patients is À0.23 G 0.08 (prolate ellipsoid). 41,45 Positive values of Q would denote the presence of an oblate surface (ie, corneas after myopic ablation with the excimer laser or orthokeratology treatments), and a null value (Q Z 0) would represent a completely spherical surface.…”

Section: Corneal Asphericitymentioning

confidence: 99%

Characterization of corneal structure in keratoconus

Piñero¹,

Nieto²,

López-Miguel³

2012

Journal of Cataract and Refractive Surgery

142

113

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“…18 Some studies agree that the human cornea Q (asphericity) values range from -0.01 to -0.80. 19 However, in our studies, we observed that if we adopted such values as a reference we would have 56% of the patients within 'normality' with a mean visual acuity of 0.79 LogMAR before ICRS, i.e. completely outside of normality.…”

Section: Discussionmentioning

confidence: 67%

Intrastromal Corneal Ring Segments Implantation in Patients with Mild Keratoconus

Rodrigues¹,

Dias²

2014

International Journal of Keratoconus and Ectatic Corneal Diseases

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Purpose: The purpose of this study is to evaluate the topographic, topometric and visual changes after implantation of Ferrara intrastromal corneal ring segments (ICRS) in grades I and II keratoconus patients. Materials and methods:The chart records of 50 consecutively operated keratoconus patients were reviewed. The patients were operated on by the same surgeon, with the manual technique. All patients were preoperatively and postoperatively evaluated with the Pentacam (OCULUS Optikgeräte, Wetzlar, Germany). The studied parameters were: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry, corneal asphericity and corneal volume.Results: Fifty eyes of 42 patients (26 males and 16 females) were analyzed. The mean preoperative UDVA was 0.91 ranging from LogMAR 0.10 to 1.30. The mean postoperative CDVA was 0.19 ranging from 0.00 to 0.54 LogMAR. The postoperative CDVA was equal or better than 0.18 in 37 cases (74%). The mean K1 decreased from 45.80D (±2.52) preoperatively to 44.27D (± 2.10) postoperatively and the mean K2 value, from 49.06D (± 2.09) to 46.22D (±1.89). The mean asphericity increased from -0.71 preoperatively to -0.29 postoperatively. The average preoperative corneal volume was 56.89 ± 3.11 mm 3 while the average postoperative corneal volume was 57.64 ± 3.05 mm 3 . Conclusion:The study supports the early indication of implantation of Ferrara ICRS in mild to moderate keratoconus cases in order to achieve good visual, keratometric and ashpericity outcomes.

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Corneal Asphericity and Apical Curvature in Children: A Cross-sectional and Longitudinal Evaluation

Cited by 61 publications

References 33 publications

Correlation of Anterior Segment Parameters in Keratoconus Patients

Correlation of Anterior Segment Parameters in Keratoconus Patients

Characterization of corneal structure in keratoconus

Intrastromal Corneal Ring Segments Implantation in Patients with Mild Keratoconus

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