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Evaluation of corneal optical properties in subjects wearing hydrogel etafilcon A contact lenses and the effect of administering mannitol-enriched sodium hyaluronate ophthalmic solution
摘要： The purpose of this study was to evaluate the effect of daily administration of mannitol-enriched sodium hyaluronate ophthalmic solution on the corneal optical properties of subjects wearing low Dk hydrogel (etafilcon A) contact lenses (CLs). Forty-five subjects wearing etafilcon A CLs daily for more than 6 months were recruited into this pilot study. Fifteen of the subjects administered a 10% mannitol-enriched 0.05% sodium hyaluronate solution (study group) once daily and 30 subjects did not administer any ophthalmic solution (control group). The subjects were examined at baseline and one month after recruitment. Changes in central corneal thickness (CCT) and corneal light backscatter were evaluated by Scheimpflug imaging (Pentacam HR). Changes in corneal total high-order aberration, corneal spherical aberration, coma, and trefoil were evaluated using the OPD scan II. At one month, corneal light backscatter decreased significantly in the study group (#18.30 arbitrary units; P,0.05) and this was highly correlated with a decrease in CCT (R=0.81; P=0.04). The decrease in corneal total high-order aberration, spherical aberration, and coma was significantly higher in the study group than in the control group (P,0.05). No changes in corneal light backscatter or CCT were found in the control group during follow-up. Once-daily administration of a mannitol-enriched lubricant ophthalmic solution was effective for improving the corneal optical quality and reducing corneal swelling in subjects wearing low Dk hydrogel (etafilcon A) CLs during one month follow-up.
关键词： Scheimpflug imaging,corneal optical quality,corneal backscattering,corneal high-order aberrations,contact lens,hypertonic lubricant solution
更新于2025-09-09 09:28:46
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Association between multifocal soft contact lens decentration and visual performance
摘要： Purpose: The aim of this study was to assess the association between decentration of several commercial multifocal soft contact lenses (MFCLs) and various objective and subjective visual performance variables in presbyopic and non-presbyopic participants. Materials and methods: All presbyopic (age >40 years, near add ≥+1.25 D) and non-presbyopic (age ≥18 years, no near add requirements, spherical equivalent ≤-0.50 D) participants were each fitted bilaterally with six and two MFCLs (test lens), respectively, and with one single vision lens (control lens). Lens decentration, ie, the x- and y-differences between the contact lens and pupil centers, was objectively determined. Third-order aberrations were measured and compared. Visual performance (high- and low-contrast acuities and several subjective variables) was analyzed for any associations (Pearson’s correlation, r) with MFCL decentration. Results: A total of 17 presbyopic (55.1±6.9 years) and eight non-presbyopic (31.0±3.3 years) participants completed the study. All lenses displayed a temporal–inferior decentration (x=-0.36±0.29 mm, y=-0.28±0.28 mm, mean ± SD). Compared to the control, a significant inferior decentration was found for the Proclear? MFCL Near lens in both groups (ypresbyopic =-0.26 mm, ynon-presbyopic =-0.70 mm) and for the Proclear? MFCL Distance lens in the non-presbyopic group (ynon-presbyopic =-0.69 mm). In both groups, lens-induced vertical coma (C(3, -1)) was, by at least tenfold, significantly more positive for the Proclear? MFCL Distance lens and significantly more negative for the Proclear? MFCL Near lens. In the presbyopic group, the correlation of total MFCL decentration with vision variables was weak (r<|0.191|). Conversely, a moderate but significant correlation with total MFCL decentration was found in the non-presbyopic group for most of the vision variables, indicating a decrease in vision as decentration increased. Conclusion: Certain MFCLs decentered more than others; the same lens designs also induced significant amounts of third-order aberrations. An association between MFCL decentration and seven out of nine vision variables was found in the non-presbyopic group, ie, the group where lenses were most decentered, which had larger pupils and lower levels of inherent third-order aberrations.
关键词： vision,higher-order aberrations,multifocal contact lenses,decentration
更新于2025-09-09 09:28:46
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Impact of higher-order aberrations on depth-of-field
摘要： It is well known that depth-of-focus (DOF) is influenced by optical factors (such as pupil size and monochromatic aberrations). However, neural factors such as blur sensitivity and defocus adaptation may play an important role on the extent of DOF. A series of experiments were conducted to study if optical or neural factors are most pertinent in explaining the variability of DOF across subjects. An adaptive optics system with a black and white target, a 3.8-mm artificial pupil, and a subjective criterion (based on objectionable blur) were used to measure depth of field ([DOFi]; DOF computed in the object space) in 11 participants, after at least 6 min of adaptation. This was done under three conditions: (a) with their own higher order aberrations (HOA); (b) after correction of their monochromatic HOA; and (c) after altering the HOA pattern for some participants to reflect the HOA pattern measured for a different participant. Natural DOFi and DOFi after HOA correction were positively correlated (R2 ? 0.461), but a significant decrease in DOFi (21% on average) was found after HOA correction (p ? 0.042). Effect of HOA on the intersubject variability of DOFi was 3.9 times smaller than the effect of the image neural processing. This study shows that DOFi depends on both optical and neural factors, but the latter seems to play a more important role than the former.
关键词： depth of focus,visual optics,wavefront aberrations,depth of field,physiological optics
更新于2025-09-09 09:28:46
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Repeatability and Reproducibility of Anterior Segment Measurements in Normal Eyes Using Dual Scheimpflug Analyzer
摘要： Objectives: To assess the repeatability and reproducibility of anterior segment measurements including aberrometric measurements Materials and Methods: Three repeated consecutive measurements were taken by two independent examiners. The following were evaluated: total corneal power and posterior corneal power, corneal higher-order wavefront aberrations (6.0 mm pupil), pachymetry at the central, paracentral, and peripheral zones, and anterior chamber depth (ACD). Repeatability was assessed by calculating the within-subject standard deviation (Sw), precision (Pr), repeatability (Rep), and intraclass correlation coefficient (ICC). Reproducibility was evaluated by Bland-Altman analysis. Results: Thirty eyes of 30 patients were included. The best ICC values were for corneal pachymetry and ACD. For both observers, acceptable ICC was also achieved for the other parameters, the only exceptions being posterior corneal astigmatism and total high order aberration. The 95% LoA (Limits of Agreement) values for all measurements showed small variability between the two examiners. Conclusion: The Galilei system provided reliable measurements of anterior segment parameters. Therefore, the instrument can be confidently used for routine clinical use and research purposes.
关键词： wavefront aberrations,interobserver repeatability,Galilei,intraobserver
更新于2025-09-04 15:30:14
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Comparison of Keratometry and Corneal Higher Order Aberrations between Scout Videokeratoscope and Pentacam Scheimpflug Camera
摘要： Purpose: To investigate the correlations of keratometry and corneal high order aberrations (HOAs) between the Keratron Scout videokeratoscope and the Pentacam HR Scheimpflug camera. Methods: From December 2012 to February 2013, keratometry and corneal HOAs were determined using the Keratron Scout videokeratoscope and Pentacam HR Scheimpflug camera in 23 healthy individuals (46 eyes). Results: Average keratometry showed high correlation with 95% confidence interval -0.155 ± 0.37 between the Keratron Scout and Pentacam HR. When comparing HOAs of the Keratron Scout and total corneal HOAs of Pentacam HR, total root-mean-square (RMS), and spherical aberration were positively correlated between the 2 devices (r = 0.67, p < 0.001 and r = 0.74, p < 0.001, respectively). When comparing HOAs of Keratron Scout and anterior corneal HOAs of Pentacam HR, total RMS, spherical aberration and coma were positively correlated between the 2 devices (r = 0.62, p < 0.001, r = 0.81, p < 0.001, and r = 0.52, p = 0.047, respectively). Conclusions: Although the 2 devices are based upon different principles, the Keratron Scout videokeratoscope and Pentacam HR Scheimpflug camera showed positive correlations in keratometry, total RMS, spherical aberration, and coma. Both devices may be useful for clinical applications.
关键词： Pentacam HR Scheimpflug camera,Spherical aberration,Keratometry,Keratron Scout videokeratoscope,Higher order aberrations
更新于2025-09-04 15:30:14