Sayuri Ninomiya

Light scattering and optical aberrations as objective parameters to predict visual deterioration in eyes with cataracts

Purpose: To predict the visual deterioration of eyes with cortical (CC) or nuclear (NC) cataract from objective data on ocular higher‐order aberration (HOA) and forward (FLS) and backward light scattering (BLS). Setting: Osaka University Medical School, Osaka, Japan. Methods: Twenty‐two eyes with mild NC, 41 eyes with mild CC, and 11 normal eyes were examined. Higher‐order aberrations were calculated with the Zernike polynomials up to the fourth order from the values obtained by wavefront analysis using the Hartmann‐Shack aberrometer. Forward light scattering was calculated from the size of the aberrometer spot images for the central 4 mm, and backward light scattering (BLS) was calculated from the optical density of the Scheimpflug images. The relationship between the area under the log contrast sensitivity function (AULCSF) curve and HOAs, FLS, and BLS was examined. Results: Area under the log contrast sensitivity function was moderately correlated with the HOAs, FLS, and BLS. Multiple linear regression analysis revealed that the AULCSF was predicted by the linear combination of these variables (R2=.484, P<.001). Area under the log contrast sensitivity was predicted by BLS and HOA (R2=.555) in the NC group and by FLS and HOAs (R2=.540) in the CC group. Conclusions: Loss of contrast sensitivity was predominantly due to BLS and HOA in eyes with NC and FLS and HOA in eyes with CC. Higher‐order aberrations, FLS, and BLS, variables that are obtained objectively, can be used to predict quantitatively the visual deterioration in cataractous eyes.

Effect of Aging on Ocular Light Scatter and Higher Order Aberrations

PURPOSE To study the effect of aging on ocular light scatter and higher order aberrations in humans. METHODS Seventy-six eyes of 76 normal subjects who had refractive errors but no ocular disease were studied. Their age ranged from 4 to 69 years (mean 34.8 +/- 5.8 yr). Both light scatter and total higher order aberrations were simultaneously and quantitatively measured by a Hartmann-Shack sensor for the central 4-mm-diameter pupil. Higher order aberrations were calculated from the Zernike polynomials up to the 4th order. The amount of light scatter was estimated by using the diameter of the point spread functions (PSFs) of the Hartmann images. A correction was made for the effect of the aberrations on the width of the images. Linear regression analysis was performed to investigate the effect of aging on light scatter and total higher order aberrations. RESULTS A significant correlation was found between scatter and age (Spearman rank correlation coefficient, r = 0.501, P = .001). Also, the total higher order aberrations increased significantly with age (r = 0.323, P = .005). The total higher order aberration and scatter index were not statistically significantly correlated (r = 0.184, P = .112). CONCLUSIONS These results indicate that scatter was better correlated with age than higher order aberrations.

Comparison of ocular higher-order aberrations and visual performance between photorefractive keratectomy and laser in situ keratomileusis for myopia

The purpose was to compare the ocular higher-order aberrations and the visual performance between photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). Ocular aberrations and visual performance were measured after PRK in 26 eyes, after LASIK in 39 eyes, and in 29 normal myopic control eyes. Ocular aberrations were measured with a Hartmann-Shack aberrometer. Visual performance was evaluated with grating contrast sensitivity, high and low contrast visual acuity, and letter contrast sensitivity under full correction with spectacles. The results were that the root mean square (RMS) values of ocular higher-order aberrations after PRK or LASIK were significantly greater than that of normal controls for both 4-mm and 6-mm zones (PRK; 0.22 ± 0.09 and 0.85 ± 0.24µm, LASIK; 0.20 ± 0.06 and 0.82 ± 0.24µm, normal; 0.10 ± 0.03 and 0.33 ± 0.11µm. P < 0.05 between PRK and normal, LASIK and normal, One Way ANOVA on Ranks). There were no significant differences between PRK and LASIK. The ocular higher-order aberrations increased in proportion with the attempted refractive correction by PRK and LASIK. The ocular higherorder aberrations correlated better with grating contrast sensitivity, low contrast visual acuity, and letter contrast sensitivity than with high contrast visual acuity. There was no difference among normal, PRK and LASIK in all the visual function tests, except between normal and PRK, or between normal and LASIK with letter contrast sensitivity. In conclusion, there was no difference in both ocular higher-order aberrations and visual performance between PRK and LASIK. The result suggests that surgeons can choose refractive procedures according to the corneal conditions or daily activities of patients.

Tear Film Break-up Time Evaluated by Real-Time Hartmann-Shack Wavefront Sensing

PurposeTo develop a novel method for measuring tear break-up time (BUT) by continuously measuring higher order wavefront aberrations using a Hartmann-Shack (H-S) aberrometer.MethodsWavefront aberrations up to the sixth order for a 4-mm pupil were measured in six eyes of six normal subjects using an H-S aberrometer. The aberrometry was performed once every second for up to 50 s under topical anesthesia. The sequence of the points was divided into two stages, and the BUT was defined as the wavefront border of the stages (WFBUT). The WFBUT was compared with the BUT by the conventional fluorescein method (FLBUT) or by the disruption of placid-ring images (PLBUT).ResultsIn three eyes, the WFBUT (average, 10.9 ± 1.1 s) was shorter than the PLBUT (average, 17.5 ± 2.5 s), while in the other three eyes the WFBUT (average, 21.5 ± 2.2 s) was longer than PLBUT (average, 8.1 ± 2.2 s). The FLBUT was shorter than WFBUT or PLBUT in most cases.ConclusionsThe tear break-up time measured by H-S aberrometer may be used as a practical measure of tear break-up. Jpn J Ophthalmol 2006;50:85–89

Wavefront analysis in Eyes With Accommodative Spasm

PURPOSE To investigate changes of spherical aberration in eyes with accommodative spasm. DESIGN Case reports. METHODS Four eyes of two patients with accommodative spasm were studied. Ocular spherical aberration was measured with a Hartmann-Shack wavefront aberrometer for the central 4-mm zone. RESULTS The root mean square values of spherical aberration were negative (-0.086 +/- 0.026 microm root mean square). However, when the spasm of accommodation was cured or treated with a cycloplegic agent, the value shifted toward positivity (0.025 +/- 0.004 microm root mean square). CONCLUSIONS Excessive accommodative tone is manifested objectively by negative spherical aberration in eyes with accommodative spasm.

Optical Quality of the Eye Degraded by Time-Varying Wavefront Aberrations with Tear Film Dynamics

PurposeWavefront aberrations (WFAs) of the eye vary with time because of the tear film dynamics. We investigated, using a simulation method, the variation of optical quality with time-varying wavefront measurements of 13 eyes with different refractions.MethodsWFAs of 13 normal eyes of 13 subjects were measured every second for 10 s. First, we simulated WFAs with conventional corneal laser refractive surgery by subtracting the second-order aberrations of the least aberrated measurement from measured consecutive WFAs. Second, we simulated customized refractive surgery by subtracting the second- to sixth-order aberrations of the least aberrated measurement from measured consecutive WFAs. We calculated Strehl ratios and retinal images from these corrected consecutive WFAs.ResultsIn one eye, the root mean square (RMS) values of WFAs with a second-order correction were sometimes smaller than those of WFAs with a second- to sixth-order correction, when these were compared at the same time point after a blink. However, in the other 12 eyes, the RMS values with second- to sixth-order corrections were smaller than those with only a second-order correction. In eight eyes, the Strehl ratios with second- to sixth-order corrections were larger than those with second-order corrections. In the remaining five eyes, Strehl ratios with second- to sixth-order corrections were sometimes smaller than those with second-order corrections.ConclusionsIn a simulation, the correction of time-invariant higher order aberrations usually reduced RMS values, but it did not always result in higher Strehl ratios than those obtained with only second-order corrections. Jpn J Ophthalmol 2007;51:258–264 @ Japanese Ophthalmological Society 2007

Effect of low-addition soft contact lenses with decentered optical design on myopia progression in children: a pilot study.

Purpose To investigate the effect of low-addition soft contact lenses (CLs) with decentered optical design on the progression of myopia in children in a pilot study. Subjects and methods Twenty-four Japanese children age 10–16 years with baseline myopia of −0.75 to −3.50 D sphere and ≤1.00 D cylinder were studied. The new CLs were designed to have a nasal decentration with the optical center centered on the line of sight, and with progressive-addition power of +0.5 D peripherally. Monofocal soft CLs were used as controls. A pair of new CLs or control CLs was randomly assigned to the children, and they wore the lenses for 12 months during the first phase. Then, the type of CLs was changed, ie, a crossover design, and the children were observed for another 12 months during the second phase. The end points were changes in axial length and refractive error (spherical equivalent) under cycloplegia. Results The change of axial length in the new-CL and control-CL groups was not different between 12 months and baseline, the change of axial length between 12 months and 1 month in the new-CL group (0.09±0.08 mm) was significantly smaller (47%) than that in the control-CL group (0.17±0.08 mm, P<0.05). During the same period, the change of refractive error in the new-CL group was not significantly different from that in the control group. Neither the change in axial length nor refractive error in the new-CL group was significantly different from those in the control-CL group in the second phase. Conclusion This pilot study suggests that low-addition soft CLs with decentered optical design can reduce the degree of axial elongation in myopic children after an initial transient phase of CL wear. The reduction of the progression of myopia by low-addition soft CLs warrants further investigations.