Higher Order Aberrations Induced by Soft Contact Lenses in Normal Eyes with Myopia

Optical Quality and Visual Performance With Different Toric Contact Lens Designs

OBJECTIVES

To evaluate the optical quality of different toric contact lens (CL) designs and compare their on-eye visual correction performance.

METHODS

Twenty soft CL wearers aged 20 to 39 years were enrolled. Two daily disposable silicone-hydrogel toric CLs were tested: the "Eyelid Stabilized Design" (ESD-CL) and prism-ballast design (PB-CL); a spherical daily disposable silicone hydrogel CL (spherical CL) was used as a control. On-eye performance was compared for corrected distance visual acuity (CDVA), astigmatism, and ocular higher-order aberrations (HOAs); astigmatism and ocular HOAs were measured with a wavefront sensor. The subjective quality of vision, rated for "blurred vision" and "double vision," lens rotation, and fitting were also compared.

RESULTS

The ESD-CLs, PB-CL, and no-CL provided better CDVA than spherical CL ( P <0.05). Compared with spherical CL and no CL, PB-CL and ESD-CLs caused significantly lesser astigmatism ( P <0.05). Coma was significantly lesser with ESD-CLs than that with PB-CL ( P <0.05); total HOAs did not differ among the four conditions. The subjective ratings for blurred and double vision were significantly lower with ESD-CLs than those with spherical CL ( P <0.05).

CONCLUSIONS

Toric CLs provide a better CDVA than spherical CLs. However, differences in coma and subjective symptoms may occur because of the design of toric CLs.

Spherical aberrations and their role in modern ophthalmology

Spherical aberration is an imperfection of the optical system of the human eye. The role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation is reviewed. Spherical aberration is an imperfection of the optical system of the human eye. In most cases, due to well-developed neuroadaptation, it is insignificant for the perception of the image. Nevertheless, its role in modern ophthalmology is far from straightforward. On the one hand, there are clinical scenarios in which an excess of spherical aberration degrades the retinal image and leads to a high dissatisfaction rate among patients.©Recently, there is a growing interest in the modulation of spherical aberration in the clinical setting. Modern intraocular lenses as well as laser refractive procedures are aimed at interfering with spherical aberrations of the optical system in order to increase range of pseudoaccommodation. Here, we review the role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation.

Effects on Wavefront Aberration after Short-term Wear of Senofilcon A Photochromic Contact Lens

BACKGROUND

To assess the variability in wavefront aberrations with short-term wear of photochromic senofilcon A contact lenses in both its activated and inactive states.

METHODS AND MATERIAL

In this cross-sectional study, 20 participants who had previously used soft contact lenses were enrolled. Corneal aberrometry measurements were performed on each subject, without contact lenses, using Sirius Scheimpflug-Placido topography. The photochromic lenses were illuminated using a blue-violet light (λ max = 420 nm) so as to provoke an activated state, and measurements were taken with the lenses inserted, in both states. The root mean square (RMS) of the aberrations was calculated, and the higher- and lower-order aberrations, astigmatism, coma, spherical aberration, and trefoil measurements were evaluated using a 5.0-mm pupil diameter.

RESULTS

The average contact lens sphere power was - 2.33 ± 1.07 D. The mean refractive errors with contact lens wear were 0.07 ± 0.18 D for the sphere and - 0.26 ± 0.15 D for the cylinder. The mean RMS values for all the corneal aberrations showed no statistically significant differences with and without contact lenses (p > 0.05). In a bivariate correlation analysis, there was a positive correlation between contact lens sphere power and coma (vertical and horizontal) in the activated state (r = 0.455, p = 0.44 and r = 0.495, p = 0.27, respectively).

CONCLUSION

The photochromic contact lenses did not influence ocular aberration during short-term wear, even when the photochromatic additive was activated. This property may help to provide more comfortable vision with lens wear. This finding needs to be verified by further studies.

Biometry and corneal aberrations after cataract surgery in childhood

Background

To report long‐term biometric and refractive outcomes in a group of Danish children after surgery for childhood cataract.

Methods

Children between 7 and 18 years who had undergone uni‐ or bilateral cataract surgery at the Department of Ophthalmology, Rigshospitalet, Denmark, were examined in this cross‐sectional study. Swept source optical coherence tomography (OCT) based optical biometry (IOLmaster 700) and anterior tomography (Pentacam) was performed. Healthy fellow eyes from those with unilateral cataract were used as controls.

Results

We included 56 children in the study with a median age at surgery of 43.8 months (1.6–137.6). The amount of higher order aberrations was significantly increased in operated eyes (median root mean square 0.461 μm [range 0.264–1.484]) compared with non‐operated eyes (median root mean square 0.337 μm [range 0.162–0.498], p < 0.001). Younger age at surgery was positively associated with more higher order aberrations at follow‐up (p < 0.001), but we found no significant associations between the amount of higher order aberrations and visual acuity or contrast vision. Longer axial length was associated to glaucoma while shorter axial length was associated to strabismus (p < 0.001).

Conclusions

Eyes operated for childhood cataract have higher order aberrations compared with non‐operated eyes. Higher order aberrations are complex refractive errors that cannot be corrected by normal lenses and may contribute to poor visual outcomes for the children. We found an association between young age at surgery and higher order aberrations.

Refractive, visual, and subjective quality of vision outcomes for very high myopia LASIK from - 10.00 to - 13.50 diopters

Background

To evaluate laser-assisted in situ keratomileusis (LASIK) outcomes, subjective quality of vision (QoV) and patient satisfaction in eyes with very high myopia (VHM) above − 10.00 diopters (D).

Methods

Consecutive myopic and myopic-astigmatism eyes with spherical equivalent (SEQ) ranging between − 10.00 to − 13.50 D underwent LASIK with the WaveLight® Allegretto Wave® Eye-Q 400 Hz excimer laser. Treatment accuracy, efficacy, safety, stability, cylinder vectors, and higher-order aberrations were evaluated, together with subjective QoV and night vision disturbances (NVDs).

Results

114 eyes had a preoperative SEQ of − 11.02 ± 0.81 D, with a median follow-up of 24 months. A total of 72, 84, and 94% of eyes were within ± 0.50, ± 0.75 and ± 1.00 D of intended SEQ (R² = 0.71). The efficacy index was 0.93 ± 0.20, with 51 and 81% of eyes achieving 20/20 and 20/25. The astigmatism correction index was 0.95 ± 0.33. The safety index was 1.05 ± 0.12. The average myopic regression was − 0.51 ± 0.38 D. Preoperative QoV scores improved significantly postoperatively (7.5 ± 0.8 vs. 9.1 ± 0.7; P <  0.001), with less NVDs (P <  0.001). Total, spherical and coma root mean square (RMS) postoperative ocular higher-order aberrations were 1.07 ± 0.34, 0.67 ± 0.25, and 0.70 ± 0.40 μm.

Conclusions

Very high myopia LASIK between − 10.00 to − 13.50 D is safe and results in good visual outcomes, with high patient satisfaction and a significant improvement in patient-reported QoV after surgery. Appropriately selected patients within this very high myopia group can be included as LASIK candidates.

[Wavefront and accommodation parameters under different conditions of correction in myopia and hyperopia]

PURPOSE

To compare the wavefront and accommodation parameters without correction and in soft contact lenses (SCL) in natural and cycloplegic conditions in eyes with myopia and hyperopia.

MATERIAL AND METHODS

A total of 142 myopic (mean -5.6±1.4 D) and 48 hyperopic (mean +3.5±1.1 D) eyes were examined in 95 patients aged 5-32 years (mean age 16.9±0.9 years) to compare the wavefront aberrations without correction and with different SCL before and after cycloplegia (two drops of cyclopentolate hydrochloride 1%). The device was set up for 4 mm zone for both narrow and wide pupils. To compare the accommodation parameters under different correction conditions, 85 patients aged 8-23 years (mean age 14.9±0.6 years) with average myopia of (-)5.27±1.4D (123 eyes) and average hyperopia of +3.53±1.2 D (46 eyes) were chosen from the study group. Among the measured parameters are objective accommodative response (OAR), relative accommodation reserves (RAR), pseudoaccumulation amplitude (PA), higher-order aberrations: RMSHOAs, 6-9 Trefoil, 7-8 Coma, spherical aberration (SA).

RESULTS

In myopic eyes with SCL Coma 7 decreases, Coma 8 increases with transition to positive values, and Trefoil 9 increases. In hyperopic eyes, trefoil 6 decreases, Coma 7-8 go negative. In myopic or hyperopic eyes with SCL, SA goes from positive to negative. In both myopia and hyperopia, accommodation and PA rates are higher in SCL than in glasses.

CONCLUSION

SCL change certain wavefront parameters for myopia and hyperopia in different ways. The accommodation parameters in SCL are elevated in both myopia and hyperopia. The negative spherical aberration induced by contact lenses improves the accommodative response. The revealed features should be considered in the development of correction methods that target refractogenesis.

Topographic characteristics after Descemet's membrane endothelial keratoplasty and Descemet's stripping automated endothelial keratoplasty

PURPOSE

To investigate the topographic characteristics of the posterior corneal surface after Descemet's endothelial membrane keratoplasty (DMEK) and Descemet's stripping automated endothelial keratoplasty (DSAEK) and their effects on postoperative visual acuity.

METHODS

Nineteen eyes of 19 patients after DMEK, 23 eyes of 23 patients after DSAEK, and 18 eyes of 18 control subjects were retrospectively analyzed. Best spectacle-corrected visual acuity (BSCVA), aberration factors (higher-order aberrations [HOAs], spherical aberrations [SAs], and coma aberrations [Comas] at 6.0 mm) were evaluated preoperatively and at 1, 3, and 6 months postoperatively. The posterior refractive pattern of the topography map was classified into 5 grades (0-5) (posterior color grade) using anterior segment optical coherence tomography. Correlations between BSCVA and some factors (abbreviation factors, posterior color grade) were analyzed.

RESULTS

BSCVA was significantly better after DMEK than after DSAEK (P < 0.001). Posterior HOAs, SAs, and Comas after each type of endothelial keratoplasty were significantly greater compared to control (P < 0.01). Posterior HOAs, total/anterior/posterior SAs, and posterior color grade were significantly lower in the DMEK group than in the DSAEK group at 3 months (P < 0.024 [posterior HOAs], P = 0.047 [total SA], P < 0.001 [anterior SAs], P = 0.021 [posterior SAs], and P < 0.001 [posterior color grade]) and 6 months postoperatively (P = 0.034 [posterior HOAs], P < 0.001 [total SAs], P < 0.001 [anterior SAs], P = 0.013 [posterior SAs], and P = 0.004 [posterior color grade]). BSCVA was significantly correlated with HOAs, SAs, and posterior color grade (P < 0.001 for all except anterior HOAs [P = 0.004]).

CONCLUSIONS

High posterior color grades were associated with larger aberration factors and had a negative effect on visual function after endothelial keratoplasty. Rapid improvement of visual function after DMEK may be attributed to less change at the posterior surface.

Assessment of aberrations and visual quality differences between myopic and astigmatic eyes before and after contact lens application

OBJECTIVE:

To evaluate the aberration and visual quality differences between myopic and astigmatic eyes before and after contact lens application by using corneal aberrometer and low- contrast sensitivity chart.

METHODS:

Eighty eyes of 40 patients were included in this study. Patients were divided into two groups as myopic (40 eyes, n=20) and astigmatic groups (40 eyes, n=20). We used aspheric Balafilcon A (Purevision and Purevision Toric Bausch&Lomb, Rochester, USA) lenses for each group. Corneal aberrations and low-contrast sensitivity values were measured and compared for each patient in both groups.

RESULTS:

There were no statistically significant differences between myopic and astigmatic groups when we compared low-contrast sensitivity values for both on- and off-eyes. Mean total higher-order aberration (HOA) values for off-eye, were 0.29±0.10 μm, and 0.33±0.10 μm for on-eye in the myopic group, while they were 0.42±0.14 μm in off-eye and 0.37±0.23 μm in on-eye in the astigmatic group. Off-eye mean coma, irregular astigmatism and total higher-order aberration RMS (root-mean-square) values were significantly higher in the astigmatic group compared to the myopic group (p=0.006, p=0.001, p=0.001) but mean on-eye RMS values were not.

CONCLUSION:

Myopic and astigmatic patients differ in terms of high-order aberrations and these differences cannot be equalized after contact lens application, but visual quality can be improved in both patients by using contact lenses.

Visual and optical performance of silicone hydrogel contact lenses for moderate myopia

Purpose

To compare the short-term visual and optical performance of silicone hydrogel contact lenses for myopia ≥ −3.00D.

Methods

This was a short-term, non-dispense, double-masked, randomized study investigating Night&Day (ND), PureVision (PV), O2 Optix (O2), Biofinity (BF), Acuvue Advance (AA) and Acuvue OASYS for myopia ≥ −3.00D. Testing was conducted under scotopic conditions. Measures (one eye only) included: high- and low-contrast visual acuity (HCVA/LCVA), contrast sensitivity, subjective clarity of vision ratings (0-100 scale using reference images, with test image representing grade 50) and ocular aberrations (up to the 4th order, analyzed across individual scotopic pupil sizes).

Results

Three males and 27 females participated, with a mean (± SD) age of 24.9 ± 7.7 yrs (range 19 to 53 yrs), sphere of −5.30 ± 1.73D (range −3.00 to −10.75D) and cylinder −0.36 ± 0.23D (range 0 to −0.75D). Mean (± SEM) logMAR HCVA ranged from 0.06 (PV) to 0.10 (AA) (± 0.02), LCVA from 0.33 (BF) to 0.40 (AA) (± 0.02) and contrast sensitivity from 2.33 (BF) to 2.53 (ND) (± 0.15) (differences not statistically significant; all p > 0.05). Subjective ratings for the test image ranged from 59 (PV) to 64 (ND) (± 4) and 56 (AA) to 65 (ND) (± 4), for monochromatic and polychromatic reference images, respectively (all p > 0.05). There was a statistically significant impact on ocular aberrations with all study lenses compared to no lens. Between-lens differences were statistically significant for defocus (Z⁰₂), horizontal coma (Z ¹₃) and spherical aberration (Z⁰₄).

Conclusions

Despite some differences in ocular aberrations, there were no significant differences in HCVA, LCVA, contrast sensitivity or subjective ratings across lenses.

Higher-order aberrations when wearing sphere and toric soft contact lenses

PURPOSE

To determine the on-eye effect of spherical and toric contact lens design on higher-order aberrations (HOA).

METHODS

Thirty eyes (15 subjects) entered a masked, randomized, cross-over study. Each eye was fitted with the spherical and toric lens of the following brands in random order: Acuvue Advance, Biomedics 55, Frequency 55, and SofLens 66. HOAs were measured using the Zywave II Aberrometer over a 6-mm aperture up to fifth order. A linear model accounting for the fixed effect of lens type and random effects of subject and eye was created. Paired t-tests were completed between lens brands within the spherical and toric lenses and between the spherical and toric lens within each brand. Best-corrected visual acuity (VA) was measured and compared.

RESULTS

No clinically meaningful differences in total HOAs were found between brands or between the spherical and toric lens within a brand. Positive spherical aberration (SA) was reduced by all spherical and toric lenses compared to wearing no lens by 0.07 to 0.23 microm (p < 0.0001). Frequency toric induced the greatest change in SA. The thin-zone design lens (Acuvue Advance for Astigmatism) had a statistically different amount of vertical coma (-0.04 microm) than the three prism-balast toric lenses (0.11 to 0.23 microm; p < 0.0001). SofLens toric had the greatest amount of vertical coma, but better VA than Acuvue Advance for Astigmatism and Frequency toric. With the exception of Acuvue Advance for Astigmatism, toric lenses had greater absolute magnitude of vertical coma than their sphere counterparts (all p < 0.002). No other significant HOA differences were observed.

CONCLUSIONS

Toric contact lenses with prism-ballast designs demonstrated more vertical coma, but better VA. Positive SA was reduced by spherical and toric contact lenses. The visual quality effect of lens design and material on induced HOAs warrants further investigation.

Effect of higher-order aberrations on visual function in keratoconic eyes with a rigid gas permeable contact lens

PURPOSE

To study the effect of higher-order aberrations (HOAs) on visual function in keratoconus with a rigid gas permeable (RGP) contact lens (CLs).

DESIGN

Retrospective nonrandomized study.

METHODS

Thirteen eyes of 10 subjects with keratoconus who wore a RGP CLs (KC-RGP group), 15 eyes of nine normal subjects (normal group), and 14 eyes of nine subjects who wore a RGP CLs (RGP group) who had no ocular diseases except for refractive errors and had 20/20 or better-corrected visual acuity were included in this study. The root-mean-square (RMS) of the third-, fourth-, fifth-, and sixth-order Zernike coefficients (total HOAs), the RMS of the third-order Zernike coefficients (S3) (coma-like aberration), the RMS of the fourth-order coefficients (S4) (spherical-like aberrations), and the area under the log contrast sensitivity function (AULCSF) were evaluated.

RESULTS

The AULCSF in the KC-RGP group was significantly lower than in the other two groups. The total HOAs, S3, and S4 in the KC-RGP group were significantly higher than in the other two groups. There were significant negative correlations between the area under the log contrast sensitivity function and the total HOAs, S3, and S4.

CONCLUSIONS

The visual performance in a keratoconic eye with a RGP CLs degrades compared with normal eyes with and without RGP CLs, even if the corrected VA is good. The degradation is assumed to be related to residual HOAs in a keratoconic eye with a RGP CLs.