Corneal tomographic changes during corneal rigid gas-permeable contact lens wear in keratoconic eyes

Association Between Family History and the Corneal Characteristics of Keratoconus in Japan

PURPOSE

The aim of this study was to determine the association between family history and corneal characteristics of keratoconus in Japan.

METHODS

The clinical records of patients with keratoconus who were interviewed regarding family history of keratoconus were retrospectively reviewed. Corneal indices derived from anterior segment optical coherence tomography were compared between the positive and negative family history groups using multiple linear regression analysis adjusted with age, sex, and history of atopy and eye rubbing.

RESULTS

A total of 2,701 eyes, including 122 eyes with positive family history, were enrolled. Based on the adjusted multiple linear regression analysis, no significant differences were found between groups with and without a family history except for paracentral and mid-peripheral corneal thickness. The adjusted mean differences in paracentral and mid-peripheral corneal thicknesses between the two groups were -10.33 (95% confidence interval -20.29 to -0.37 P -value <0.05) and -9.78 (95% confidence interval -16.70 to -2.85, P -value <0.01), respectively.

CONCLUSIONS

There was no significant association between family history and corneal indices in Japanese patients with keratoconus, except for paracentral and mid-peripheral corneal thicknesses. A Japanese patient with keratoconus who had a family history showed significantly lower paracentral and mid-peripheral corneal thicknesses than those with no family history.

Effects of Custom-Designed Soft Contact Lenses on Irregular Astigmatism Correction in Patients with Keratoconus

Purpose

To evaluate the efficacy of YOUSOFT soft contact lenses in correcting irregular astigmatism and prescription results of patients with keratoconus.

Patients and Methods

The retrospective observational study included 55 eyes (mean age, 32.2 ± 10.6 years; 36 men and 6 women) of 42 patients with keratoconus who tried YOUSOFT for rigid gas permeable (RGP) lens intolerance. Average keratometry, corneal astigmatism, and maximum keratometry were 49.4 ± 5.2 diopters (D), 3.7 ± 2.1 D, and 57.3 ± 8.2 D, respectively. Patients were divided into YOUSOFT prescription and non-prescription cases, wherein the prescription rates were calculated. YOUSOFT visual acuity was compared with spectacle-corrected distance visual acuity (CDVA) and RGP lens-CDVA.

Results

YOUSOFT was prescribed to 28 out of 42 patients (prescription rate 67%). In the YOUSOFT prescription cases, YOUSOFT-CDVA (logMAR -0.04; 95% confidence interval [CI]: -0.08 to 0.00) was significantly better than spectacle-CDVA (logMAR 0.23; 95% CI: 0.08 to 0.38; P < 0.0001), whereas YOUSOFT-CDVA (logMAR -0.03; 95% CI: -0.08 to 0.03) did not significantly differ from the RGP lens-CDVA (logMAR -0.02; 95% CI: -0.08 to 0.04; P = 0.856).

Conclusion

YOUSOFT was effective in correcting irregular corneal astigmatism, suggesting that it is highly effective in patients with RGP lens intolerance.

Regular and irregular astigmatism of bullous keratopathy using Fourier harmonic analysis with anterior segment optical coherence tomography

Bullous keratopathy (BK) is known to present with corneal edema and Descemet's folds, which can cause corneal astigmatism. However, no report quantitatively evaluated BK astigmatism by separating it into regular and irregular astigmatism. This study investigated the regular and irregular astigmatism of the anterior and posterior corneal surface with Fourier harmonic analysis and anterior segment optical coherence tomography. Preoperative data from 43 eyes of 41 BK patients who received corneal endothelial transplantation were compared with the data from 43 eyes of 43 subjects without corneal disease. Anterior and posterior cylinder power, central corneal thickness (CCT) and thinnest corneal thickness were significantly greater in BK. With Fourier harmonic analysis, BK eyes were found to have significantly larger anterior and posterior regular astigmatism, asymmetry component and higher-order irregularity. Asymmetry component and higher-order irregularity that accounted for the posterior irregular astigmatism increased as CCT increased in BK. Higher-order irregularity in the posterior cornea also positively correlated with worsening best corrected visual acuity. Subgroup analysis found significant correlations between CCT and posterior higher-order irregularity for intraocular surgery and laser iridotomy, but not Fuchs endothelial corneal dystrophy. This study has significance in that it revealed the characteristics of the corneal posterior irregular astigmatism of BK.

Fourier analysis on irregular corneal astigmatism using optical coherence tomography in various severity stages of keratoconus

PURPOSE

To investigate the diagnostic capability of Fourier indices in detecting clinical or subclinical keratoconus (KC).

DESIGN

Prospective cross-sectional study METHODS: : The study included 126 eyes with clinical KC (50 KC without any corneal scar, 50 KC with anterior corneal scar, and 26 KC with posterior scar having a history of acute corneal hydrops), 50 with topographic KC (without clinical signs), 50 with pre-topographic KC (normal topography without clinical signs), and 50 controls. Corneal tomographic data were obtained using anterior segment optical coherence tomography (OCT). Fourier analysis decomposed dioptric data from both anterior and posterior corneal surface into spherical, regular astigmatism, asymmetry, and higher-order irregularity components. The discriminating ability of the Fourier indices of pre-topographic KC, topographic KC, and clinical KC from controls were assessed after quantitative Fourier analysis of irregular corneal astigmatism.

RESULTS

Posterior asymmetry and higher-order irregularity components were significantly greater in pre-topographic KC eyes than those in controls (p<0.001 for both), with the highest area under the receiver operating characteristic curve (AUROC) of 0.778 and 0.709, respectively. The same was true for anterior asymmetry, posterior asymmetry, and posterior higher-order irregularity components in topographic KC (AUROC of 0.945, 0.941, and 0.893, respectively), whereas it was >0.948 for all Fourier components in clinical KC.

CONCLUSIONS

Fourier analysis using OCT can evaluate anterior and posterior corneal irregular astigmatism of various KC stages, from very mild to advanced, including severe cases with corneal scar. Irregular astigmatism indices from the posterior corneal surface showed the highest AUROC values in discriminating early KC stages.

Evaluation of the Relationship Between the Changes in the Corneal Biomechanical Properties and Changes in the Anterior Segment OCT Parameters Following Customized Corneal Cross-Linking

Purpose

Patients and Methods

Results

Conclusion