![]() 11 found a linear evolution in the optical quality (intraocular aberrations and ocular MTF) between eyes with clear lenses older than 40 years and eyes with a low grade of cataract. The MTF obtained from double-pass line spread function (LSF) is another parameter to measure the retinal image qualities objectively because LSF flattens as nuclear opalescence increases 10. In addition to optical aberration data, the iTrace provides the modulation transfer function (MTF) curves from 0–30 cycles/degree (cpd). The aberrations of the internal optics are directly measured by locating the spots on the retina within milliseconds 9. The iTrace (Tracey Technologies), which is a commercially available visual function analyzer that combines ray-tracing aberrometry and corneal topography, is able to sequentially projects 256 near-infrared laser beams into the eye in a specific scanning pattern 8. The isolation of aberrations that result from a crystalline lens is essential to determining the effects of crystalline lens opacities on wavefront aberration however, baseline wavefront data on isolated internal optics (lens) of the eye have not been fully investigated, because most aberrometers that used previous studies only measures the total ocular wavefront aberrations. It is also reported that a loss of contrast sensitivity closely relates to the density of nuclear cataract, as measured by Scheimpflug images 7. This decline in visual capability likely involves deterioration of retinal image qualities due to changes in higher-order aberrations of the crystalline lens 4, 5, 6. Contrast sensitivity declines with age, even in the absence of ocular pathologies, such as manifest cataract, glaucoma, or macular degeneration 3. In the early stages of cataract formation, patients may suffer from decreased visual quality (light scattering, polyopia, etc.), whereas visual acuity in standard conditions is still preserved 1.The deterioration of visual function in these patients cannot be entirely explained by spherical or cylindrical refractive errors 2. The accurate assessment of visual function interference by lens opacities can help ophthalmic surgeons choose the best time to perform cataract surgery. Understanding the wavefront optical properties of different crystalline lens opacities may help ophthalmic surgeons determine the optimal time to perform cataract surgery. Wavefront technology is useful for objective and quantitative analysis of retinal image quality deterioration in eyes with different early lenticular opacity types and densities. In the nuclear cataract group, nuclear lens density was negatively correlated with internal spherical aberrations ( r = −0.527, P = 0.005). Eyes with nuclear cataract had lower spherical-like aberrations than the other two groups in both entire eye and internal optics aberrations ( P < 0.001 and P < 0.001, respectively). Eyes with cortical cataracts showed significantly higher coma-like aberrations compared to the other two groups in both entire eye and internal optic aberrations ( P = 0.012 and P = 0.007, respectively). In each group, wavefront aberrations in the entire eye and in the internal optics and retinal image quality were measured using a raytracing aberrometer. ![]() Forty-one eyes with nuclear cataract, 33 eyes with cortical cataract, and 29 eyes with posterior subcapsular cataract were examined. To investigate wavefront aberrations in the entire eye and in the internal optics (lens) and retinal image qualities according to different lenticular opacity types and densities. ![]()
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