Mutsumi Fuchihata

Corneal topographic analysis by 3-dimensional anterior segment optical coherence tomography after endothelial keratoplasty.

PURPOSE To investigate the characteristics of the corneal topography with three-dimensional (3-D) anterior segment optical coherence tomography (AS-OCT) following Descemets stripping automated endothelial keratoplasty (DSAEK). METHODS Thirty-four eyes of 33 patients following DSAEK were studied. In addition to conventional topographic maps, the elevation map of the intrastromal interface and pachymetric maps of the host and graft were obtained by corneal topographic analysis using 3-D AS-OCT. The coefficient of variation of the corneal power (CV-Pa, CV-Pp) and root mean squares of the corneal elevation (RMS-Ea, RMS-Ep) of the anterior and posterior corneal surfaces were determined. Based on the combination of the regularity and irregularity of the anterior and posterior surfaces, subjects were classified into four types: type 1, regular/regular; type 2, irregular/regular; type 3, regular/irregular; and type 4, irregular/irregular. RESULTS The average graft decentration was 0.59 ± 0.23 mm. The proportion of types 1, 2, 3, and 4 were 59%, 9%, 24%, and 9 %, respectively. The CV-Pa (25.8 ± 8.9) and CV-Pp (-73.9 ± 18.0) of the type 1 corneas were significantly better than that of type 2 and type 3 corneas, respectively. The RMS-Ea (5.1 ± 1.3) and RMS-Ep (26.0 ± 7.3) of the type 1 corneas were significantly better than that of type 2 and type 3 corneas. CONCLUSIONS An OCT-based corneal topographer might be useful in determining the factors associated with optical quality of the cornea following DSAEK by analyzing the topographic characteristics of host and donor separately.

Quantitative Evaluation of the Natural Progression of Keratoconus Using Three-Dimensional Optical Coherence Tomography.

PURPOSE We quantified the chronologic progression of keratoconus using anterior segment optical coherence tomography (AS-OCT). METHODS A total of 217 eyes from 113 patients with keratoconus, keratoconus suspect, or forme fruste keratoconus were evaluated by corneal tomography using swept-source OCT. Age-dependent changes in the radius of the posterior best-fit sphere (Rpost), minimum corneal thickness (Tmin), and distance from the thinnest point to the corneal vertex (Dmin) were examined over follow-up periods of up to 5.79 years and were analyzed using generalized estimating equation (GEE) nonlinear regression model. RESULTS Annual changes in Rpost (mean, -0.017 mm) and Tmin (-2.69 μm) were significantly higher in younger patients (P < 0.01, GEE nonlinear regression) and in patients with higher maximal K value (Kmax; P < 0.01, GEE nonlinear regression), whereas no changes were observed in Dmin. Even in patients 30 years or older, 14% of eyes revealed remarkable progression in Rpost. In eyes with acute hydrops, annual changes in Rpost (-0.22 mm) and Tmin (-33.8 μm) before acute corneal hydrops were more than 10 times faster than those in other eyes (P < 0.001, GEE nonlinear regression). CONCLUSIONS Chronologic measurements of corneal tomography in keratoconus demonstrated that the progression of steepening at posterior corneal surface was found not only in patients under 30 years but also in older patients, particularly in advanced keratoconus. The rate of progression can be measured by mapping of corneal curvature and thickness using OCT, and the risk of progression was greater in younger patients with steeper Kmax.

Corneal topographic analysis of patients with Mooren ulcer using 3-dimensional anterior segment optical coherence tomography.

Purpose: To investigate the corneal topography and visual function of patients with Mooren ulcer using 3-dimensional anterior segment optical coherence tomography (3-D AS-OCT). Methods: Fourteen eyes of 9 patients with Mooren ulcer were studied. Pachymetric and axial power maps were obtained by 3-D AS-OCT. The axial power maps were classified into 3 patterns by visual inspection. The distribution of the corneal dioptric power was analyzed by Fourier harmonic expansion. The magnitudes of the spherical component, asymmetry, regular astigmatism, higher-order irregularity, and radial distance from the corneal vertex to the thinnest point of the lesion were determined. Results: The axial power maps of 9 eyes were classified into arcuate patterns, 4 into crab-claw patterns, and 1 eye into an intermediate pattern. The radial distance from the corneal vertex to the thinnest point of the lesion was significantly shorter in the crab-claw pattern group than in the arcuate pattern group (P = 0.007). The magnitudes of asymmetry, regular astigmatism, and higher-order irregularity of the crab-claw pattern group were significantly greater than those of the arcuate pattern group (P = 0.017, P = 0.011, and P = 0.030, respectively). Conclusions: Three-dimensional AS-OCT is able to evaluate the corneal topography of opacified peripheral lesions in eyes with Mooren ulcer, and the results showed that irregular astigmatism is higher when the lesion is closer to the center of the cornea.

Visual Performance and Optical Quality of Standardized Asymmetric Soft Contact Lenses in Patients With Keratoconus

Purpose To evaluate the visual performance and optical quality of a standardized asymmetric soft contact lens (SCL) used for correction of higher-order aberrations (HOAs) in eyes with keratoconus. Methods We included 30 eyes (26 patients) with keratoconus (average K: 45.7 ± 2.3 diopters [D]). The patients were subjected to corneal tomography, aberrometry, measurements of manifest refraction and visual acuity (VA), and visual analog scale (VAS) assessments. The study lenses were made using a molding method and consisted of six standardized types, in which an asymmetric power distribution of approximately 2 to 12 D (2-D step) was used to correct HOAs. The lens type suitable for each eye was selected based on the corneal tomography and aberrometry data. The on-eye performance of the lens was evaluated using aberrometry (4-mm pupil), over refraction, VA, and VAS. Results The standardized asymmetric SCL improved the best spectacle-corrected VA from -0.07 ± 0.09 to -0.11 ± 0.08 logMAR (P < 0.05) and the mean VAS score from 66.2 ± 21.8 to 75.4 ± 20.5 (P < 0.05). Vertical coma decreased significantly (-0.50 ± 0.36 μm without SCL; -0.36 ± 0.34 μm with SCL; P < 0.01). In subgroup analysis, subjects in the high VAS group (score ≥ 75) accounted for 70% of all subjects, and this was the group in which the vertical coma decreased significantly from the level without the lens. Conclusions A standardized asymmetric SCL can reduce HOAs and improve vision quality when compared with spectacles in patients with keratoconus who wear rigid gas-permeable lenses.

Evaluation of corneal biomechanics in patients with keratectasia following LASIK using dynamic Scheimpflug analyzer

PurposeTo investigate the corneal biomechanics in eyes with keratectasia following LASIK using a dynamic Scheimpflug analyzer.DesignCase–Control study.MethodThe subjects in the study included 12 eyes with keratectasia after LASIK (KE), 24 eyes with keratoconus (KC), 17 eyes without keratectasia after LASIK (LASIK), and 34 eyes with normal corneas (Normal). Corneal biomechanics of the four groups were evaluated using a dynamic Scheimpflug analyzer.ResultsCompared with Normal (7.06 ± 0.54), the radius at the highest concavity (radius, mm) of LASIK (5.96 ± 0.76), KE (4.93 ± 0.61) and KC (5.39 ± 1.02) were significantly small. The Deflection Amplitude (HCDLA, mm) of Normal (0.94 ± 0.07) was significantly lower than those of KE (1.11 ± 0.10) and KC (1.06 ± 0.16), and was not significantly different from that of LASIK (0.98 ± 0.07). There were significant differences between LASIK and KE in radius and HCDLA (P < 0.05), whereas KE and KC had no differences in these parameters.ConclusionsCorneal biomechanical features evaluated using the dynamic Scheimpflug analyzer suggest that biomechanical properties in eyes with keratectasia, keratoconus, and LASIK are different from those of normal eyes. Although the biomechanics in eyes with keratectasia differs from that in eyes with LASIK, it is similar to that in eyes with keratoconus.