The Effect of Fractal Contact Lenses on Peripheral Refraction in Myopic Model Eyes

Purpose: To test multizone contact lenses in model eyes: Fractal Contact Lenses (FCLs), designed to induce myopic peripheral refractive error (PRE). Methods: Zemax ray-tracing software was employed to simulate myopic and accommodation-dependent model eyes fitted with FCLs. PRE, defined in terms of mean sphere M and 90–180 astigmatism J180, was computed at different peripheral positions, ranging from 0 to 35 in steps of 5, and for different pupil diameters (PDs). Simulated visual performance and changes in the PRE were also analyzed for contact lens decentration and model eye accommodation. For comparison purposes, the same simulations were performed with another commercially available contact lens designed for the same intended use: the Dual Focus (DF). Results: PRE was greater with FCL than with DF when both designs were tested for a 3.5 mm PD, and with and without decentration of the lenses. However, PRE depended on PD with both multizone lenses, with a remarkable reduction of the myopic relative effect for a PD of 5.5 mm. The myopic PRE with contact lenses decreased as the myopic refractive error increased, but this could be compensated by increasing the power of treatment zones. A peripheral myopic shift was also induced by the FCLs in the accommodated model eye. In regard to visual performance, a myopia under-correction with reference to the circle of least confusion was obtained in all cases for a 5.5 mm PD. The ghost images, generated by treatment zones of FCL, were dimmer than the ones produced with DF lens of the same power. Conclusions: FCLs produce a peripheral myopic defocus without compromising central vision in photopic conditions. FCLs have several design parameters that can be varied to obtain optimum results: lens diameter, number of zones, addition and asphericity; resulting in a very promising customized lens for the treatment of myopia progression.This research was supported by the Ministerio de Economia y Competitividad (grant FIS2011-23175), the Generalitat Valenciana (grant PROMETEO2009-077) and the Universitat Politecnica de Valencia (grant INNOVA SP20120569), Spain.Rodríguez Vallejo, M.; Benlloch Fornés, JI.; Pons Martí, A.; Monsoriu Serra, JA.; Furlan, WD. (2014). The Effect of Fractal Contact Lenses on Peripheral Refraction in Myopic Model Eyes. Current Eye Research. 39(12):1-10. https://doi.org/10.3109/02713683.2014.903498S110391

Extended depth of focus contact lenses vs. two commercial multifocals: Part 1. Optical performance evaluation via computed through-focus retinal image quality metrics

© 2017 Spanish General Council of Optometry Purpose To compare the computed optical performance of prototype lenses designed using deliberate manipulation of higher-order spherical aberrations to extend depth-of-focus (EDOF) with two commercial multifocals. Methods Emmetropic, presbyopic, schematic eyes were coupled with prototype EDOF and commercial multifocal lenses (Acuvue Oasys for presbyopia, AOP, Johnson & Johnson & Air Optix Aqua multifocal, AOMF, Alcon). For each test configuration, the through-focus retinal image quality (TFRIQ) values were computed over 21 vergences, ranging from −0.50 to 2.00 D, in 0.125 D steps. Analysis was performed considering eyes with three different inherent aberration profiles: five different pupils and five different lens decentration levels. Results Except the LOW design, the AOP lenses offered ‘bifocal’ like TFRIQ performance. Lens performance was relatively independent to pupil and aberrations but not centration. Contrastingly, AOMF demonstrated distance centric performance, most dominant in LOW followed by MED and HIGH designs. AOMF lenses were the most sensitive to pupil, aberrations and centration. The prototypes demonstrated a ‘lift-off’ in the TFRIQ performance, particularly at intermediate and near, without trading performance at distance. When compared with AOP and AOMF, EDOF lenses demonstrated reduced sensitivity to pupil, aberrations and centration. Conclusion With the through focus retinal image quality as the gauge of optical performance, we demonstrated that the prototype EDOF designs were less susceptible to variations in pupil, inherent ocular aberrations and decentration, compared to the commercial designs. To ascertain whether these incremental improvements translate to a clinically palpable outcome requires investigation through human trials

Association between multifocal soft contact lens decentration and visual performance

© 2016 Fedtke et al. 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

Association between multifocal soft contact lens decentration and visual performance

Cathleen Fedtke,1 Klaus Ehrmann,1,2 Varghese Thomas,1 Ravi C Bakaraju1,2 1The Brien Holden Vision Institute, Clinical Trial Research Centre, 2School&nbsp;of Optometry and Vision Science, The University of New South Wales, Sydney, NSW, Australia 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 &gt;40&nbsp;years, near add &ge;+1.25&nbsp;D) and non-presbyopic (age &ge;18 years, no near add requirements, spherical equivalent &le;-0.50&nbsp;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&rsquo;s correlation, r) with MFCL decentration. Results: A total of 17 presbyopic (55.1&plusmn;6.9&nbsp;years) and eight non-presbyopic (31.0&plusmn;3.3&nbsp;years) participants completed the study. All lenses displayed a temporal&ndash;inferior decentration (x=-0.36&plusmn;0.29&nbsp;mm, y=-0.28&plusmn;0.28&nbsp;mm, mean &plusmn; SD). Compared to the control, a significant inferior decentration was found for the Proclear&reg; MFCL Near lens in both groups (ypresbyopic =-0.26&nbsp;mm, ynon-presbyopic =-0.70&nbsp;mm) and for the Proclear&reg; MFCL Distance lens in the non-presbyopic group (ynon-presbyopic =-0.69&nbsp;mm). In both groups, lens-induced vertical coma (C(3, -1)) was, by at least tenfold, significantly more positive for the Proclear&reg; MFCL Distance lens and significantly more negative for the Proclear&reg; MFCL Near lens. In the presbyopic group, the correlation of total MFCL decentration with vision variables was weak (r&lt;|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 &shy;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. Keywords: vision, multifocal contact lenses, decentration, higher-order aberration

Visual performance with multifocal soft contact lenses in non-presbyopic myopic eyes during an adaptation period

Cathleen Fedtke,1 Klaus Ehrmann,1,2 Varghese Thomas,1 Ravi C Bakaraju,1,2 1The Brien Holden Vision Institute, Clinical Trial Research Centre, 2School of Optometry and Vision Science, The University of New South Wales, Sydney, NSW, Australia Purpose: Multifocal soft contact lenses (MFCLs) have been proposed and used for controlling the rate of myopia progression; however, little is known on the performance and adaptation with MFCLs in non-presbyopes. This study aims to evaluate the visual performance of four commercially available MFCLs in non-presbyopic myopic eyes during an adaptation period. Methods: Fifty-two experienced myopic contact lens wearers (67% female; mean age 21.4&plusmn;2.0 years) were enrolled in this trial and 40 completed the trial. Twenty-six participants (Group 1) wore Lotrafilcon B single vision (SV, control), Omafilcon A MFCL center-distance (D) and center-near (N) and the other 26 participants (Group 2) wore Lotrafilcon B SV, Lotrafilcon B MFCL N, and Balafilcon A MFCL N. Lens order was randomized. Participants wore each allocated lens for a minimum of 8 days over four scheduled visits (dispensing and three follow-up visits) with a 1-week washout period between the lens types. At each visit, high-contrast visual acuity (HCVA) (in logarithm of the minimum angle of resolution [logMAR]) and seven subjective performance variables (via questionnaire) were obtained. Power profiles of each lens type, pupil size, and contact lens centration, with lens placed on the eye, were measured. Results: The SV control outperformed the MFCLs in all variables (P&lt;0.05). There were no significant differences in HCVA over time, with the exception of monocular HCVA with Omafilcon A MFCL N, which at the end of the adaptation period had significantly (P&lt;0.05) improved by 0.10 logMAR. No differences were found between visits for any subjective variables. Subjectively, Lotrafilcon B MFCL N performed best and was the only lens that did not decenter significantly compared to the SV control. Conversely, Omafilcon A MFCL N was the worst performing and most decentered lens (P&lt;0.05, y=&minus;0.39 mm), with the greatest plus area under the power profile. Conclusion: MFCLs with greatest power variation across the optic zone, a greater plus area under the distance labeled power profile, and/or lenses that were significantly decentered resulted in the lowest subjective ratings. Over time, quality of vision with MFCLs did not change in non-presbyopic myopic participants, with the exception of Omafilcon A MFCL N, which showed some adaptation effects. Keywords: multifocal contact lenses, visual performance, contact lens centration, power profiles, non-presbyope

Visual performance with multifocal soft contact lenses in non-presbyopic myopic eyes during an adaptation period

© 2016 Fedtke et al. Purpose: Multifocal soft contact lenses (MFCLs) have been proposed and used for controlling the rate of myopia progression; however, little is known on the performance and adaptation with MFCLs in non-presbyopes. This study aims to evaluate the visual performance of four commercially available MFCLs in non-presbyopic myopic eyes during an adaptation period. Methods: Fifty-two experienced myopic contact lens wearers (67% female; mean age 21.4±2.0 years) were enrolled in this trial and 40 completed the trial. Twenty-six participants (Group 1) wore Lotrafilcon B single vision (SV, control), Omafilcon A MFCL center-distance (D) and center-near (N) and the other 26 participants (Group 2) wore Lotrafilcon B SV, Lotrafilcon B MFCL N, and Balafilcon A MFCL N. Lens order was randomized. Participants wore each allocated lens for a minimum of 8 days over four scheduled visits (dispensing and three follow-up visits) with a 1-week washout period between the lens types. At each visit, high-contrast visual acuity (HCVA) (in logarithm of the minimum angle of resolution [logMAR]) and seven subjective performance variables (via questionnaire) were obtained. Power profiles of each lens type, pupil size, and contact lens centration, with lens placed on the eye, were measured. Results: The SV control outperformed the MFCLs in all variables (P<0.05). There were no significant differences in HCVA over time, with the exception of monocular HCVA with Omafilcon A MFCL N, which at the end of the adaptation period had significantly (P<0.05) improved by 0.10 logMAR. No differences were found between visits for any subjective variables. Subjectively, Lotrafilcon B MFCL N performed best and was the only lens that did not decenter significantly compared to the SV control. Conversely, Omafilcon A MFCL N was the worst performing and most decentered lens (P<0.05, y=-0.39 mm), with the greatest plus area under the power profile. Conclusion: MFCLs with greatest power variation across the optic zone, a greater plus area under the distance labeled power profile, and/or lenses that were significantly decentered resulted in the lowest subjective ratings. Over time, quality of vision with MFCLs did not change in non-presbyopic myopic participants, with the exception of Omafilcon A MFCL N, which showed some adaptation effects

Association between multifocal soft contact lens decentration and visual performance

© 2016 Fedtke et al. 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

Effect of cylinder power and axis changes on vision in astigmatic participants

J Sha,1 C Fedtke,1,2 D Tilia,1,2 N Yeotikar,1 M Jong,1,2 J Diec,1 V Thomas,1 RC Bakaraju1,2 1Brien Holden Vision Institute, Sydney, NSW, Australia; 2School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia Purpose: To ascertain the impact of altering cylinder (cyl) power and axis on vision in astigmatism. Methods: In a prospective, randomized, participant-masked, crossover clinical trial, 28 astigmatic participants were tested for the following conditions on different days: full sphero-cyl correction and undercorrection by 0.25, 0.50, and 0.75 DC while maintaining spherical equivalence. Axis was also misaligned between &ndash;30&deg; and +30&deg;, in 10&deg; steps. For each configuration, monocular high- and low-contrast visual acuities (HCVA, LCVA) were measured at 6 m, and participants rated vision clarity (1&ndash;10), vision satisfaction (1&ndash;10), and vision acceptability (yes/no). Linear mixed models were used to compare visual performance in the overall group and in low, medium, and high cyl subgroups. Results: Undercorrecting cyl power affected all groups equally (P&ge;0.073). Undercorrection by 0.75 DC was significantly different to full cyl power for all variables (P&le;0.007), while 0.25 DC undercorrection did not cause any significant decreases (P&gt;0.05). Undercorrection by 0.50 DC was significantly different to full cyl power for HCVA (P=0.006, however not clinically significant) and vision acceptability (P=0.034). Axis misalignment affected the cyl groups differently (P&lt;0.001), with the greatest impact in the high cyl group, followed by the medium then the low-cyl group. Misalignment by &plusmn;30&deg; caused significant decreases in almost all cases (P&le;0.003), while misalignments by &plusmn;10&deg; or &plusmn;20&deg; caused significant decreases for some cyl groups and test variables. Conclusion: Undercorrection of cyl by &le;0.50 DC while maintaining spherical equivalence has no significant effect on HCVA, LCVA, vision clarity, and vision satisfaction, while the amount of axis misalignment that can be tolerated is dependent on the cyl power. These results may have practical ophthalmic applications, such as reducing the total number of stock keeping units of toric contact lenses. Keywords: astigmatism, toric, sensitivity, misalignment, visual performanc

Effects of relative negative spherical aberration in single vision contact lens visual performance

© 2018 Kho et al. Objective: The study aimed to compare the visual performance of contact lenses with and without negative spherical aberration (SA) over 5 days of wear. Methods: At baseline, 32 myopic participants (aged 18-33 years) were fitted in a randomized order with two lenses (test lens with minimal or no SA and 1-Day Acuvue Moist designed with negative SA) for 5 days (minimum 6 hours wear/day). Participants returned for a follow-up visit. This consisted of on-axis SA measurements; high-and low-contrast visual acuities at 6 m; highcontrast acuities at 70 and 40 cm; low-illumination, low-contrast acuity at 6 m; stereopsis at 40 cm; horizontal phorias at 3 m and 33 cm; and ±2.00 D monocular accommodative facility at 33 cm. Participants also rated (1-10 scale) vision quality (clarity and lack of ghosting for distance, intermediate, near, driving vision and vision stability during day-and night-time), overall vision satisfaction, ocular comfort, and willingness to purchase (yes/no response). Results: 1-Day Acuvue Moist induced significantly (p0.05) in acuity, binocular vision, and all subjective metrics except vision stability between lenses where the test lens was rated to provide more stable vision (p<0.05). Conclusion: Contrary to expectations, incorporating negative SA in single vision soft contact lenses did not improve visual performance in non-presbyopic adult myopes

Effects of relative negative spherical aberration in single vision contact lens visual performance

Danny Kho,1 Cathleen Fedtke,1,2 Daniel Tilia,1,2 Jennie Diec,1 Jennifer Sha,1 Varghese Thomas,1 Ravi C Bakaraju1,2 1Brien Holden Vision Institute, Clinical Trial Research Centre, Sydney, NSW, Australia, 2School of Optometry and Vision Sciences, University of New South Wales, Sydney, NSW, Australia Objective: The study aimed to compare the visual performance of contact lenses with and without negative spherical aberration (SA) over 5 days of wear. Methods: At baseline, 32 myopic participants (aged 18&ndash;33 years) were fitted in a randomized order with two lenses (test lens with minimal or no SA and 1-Day Acuvue Moist designed with negative SA) for 5 days (minimum 6 hours wear/day). Participants returned for a follow-up visit. This consisted of on-axis SA measurements; high- and low-contrast visual acuities at 6 m; high-contrast acuities at 70 and 40 cm; low-illumination, low-contrast acuity at 6 m; stereopsis at 40 cm; horizontal phorias at 3 m and 33 cm; and &plusmn;2.00 D monocular accommodative facility at 33 cm. Participants also rated (1&ndash;10 scale) vision quality (clarity and lack of ghosting for distance, intermediate, near, driving vision and vision stability during day- and night-time), overall vision satisfaction, ocular comfort, and willingness to purchase (yes/no response). Results: 1-Day Acuvue Moist induced significantly (p&lt;0.05) more negative SA at distance (∆=0.078 &mu;m) and near (∆=0.064 &mu;m) compared to the test lens, for a 6 mm pupil. There were no significant differences (p&gt;0.05) in acuity, binocular vision, and all subjective metrics except vision stability between lenses where the test lens was rated to provide more stable vision (p&lt;0.05). Conclusion: Contrary to expectations, incorporating negative SA in single vision soft contact lenses did not improve visual performance in non-presbyopic adult myopes. Keywords: soft contact lens, spherical aberration, power profile, visual acuit