ZERNIKE ASTIGMATISM AND VISUAL PERFORMANCE IN MYOPIC EYES BY RIGID GAS PERMEABLE CONTACT LENSES WEAR

To investigate the effects of rigid-gas-permeable contact lens(RGP-CL)wear on Zernike astigmatism and visual performance in myopic eyes.Methods:A wavefront sensor was used to evaluate Zernike astigmatism for 21 eyes with minimum astigmatism and 18 eyes with moderate astigmatism under three different modes of refractive correction:the RGP-CL,spectacle lens correcting spherical equivalent(SL)and spectacle lens fully correcting spherical error and astigmatism(fSL).Contrast visual acuity was assessed with a VA tester at four contrast levels and two luminance backgrounds.Results:Compared to the SL wear,RGP-CL wear changed the main axis astigmatism(Z_(2)^(2))from
0:09-0:34 to 0.34-0.22 for the minimum astigmatism group,while the contrast VA was improved about 0.05 LogMAR(F=8:06,p<0:01).For the group with moderate astigmatism,significant reduction in Z_(2)^(2)was found for both fSL wear(t=4:78,p<0:001)and RGP-CL wear(t=6:29,p<0:0001).The changes in astigmatism were significantly correlated between the fSL and RGP-CL wears(r=0:897,p<0:0001 for Z_(2)^(-2);and r=0:643,p=0:004 for Z_(2)^(2)).Contrast VA was significantly improved for both fSL and RGP-CL wears and the improvements were significantly correlated between each other for all four contrast levels and two backgrounds.Conclusion:RGP-CL wear induces astigmatism for the eyes with minor astigmatism probably due to a correction of corneal astigmatism and thus a manifesting of the lens astigmatism.For the astigmatic eyes,RGP-CL wear has similar effect on correcting astigmatism as the spectacle lens wear with spherical-cylinder correction and also produces similar visual improvement.

Visual quality of juvenile myopes wearing multifocal soft contact lenses

Background:It is unclear whether multifocal soft contact lenses(MFSCLs)affect visual quality when they are used for myopia control in juvenile myopes.The aim of this study was,therefore,to investigate the effect of MFSCLs on visual quality among juvenile myopia subjects.Methods:In a prospective,intervention study,thirty-three juvenile myopes were enrolled.Visual perception was assessed by a quality of vision(QoV)questionnaire with spectacles at baseline and after 1 month of MFSCL wear.At the one-month visit,the high(96%)contrast distance visual acuity(distance HCVA)and low(10%)contrast distance visual acuity(distance LCVA)were measured with single vision spectacle lenses,single vision soft contact lenses(SVSCLs)and MFSCLs in a random order.Wavefront aberrations were measured with SVSCLs,with MFSCLs,and without any correction.Results:Neither distance HCVA(p>0.05)nor distance LCVA(p>0.05)revealed any significant difference between MFSCLs,SVSCLs and single vision spectacle lenses.The overall score(the sum of ten symptoms)of the QoV questionnaire did not show a statistically significant difference between spectacles at baseline and after 1 month of MFSCL wear(p=0.357).The results showed that the frequency(p<0.001),severity(p=0.001)and bothersome degree(p=0.016)of halos were significantly worse when wearing MFSCLs than when wearing single vision spectacle lenses.In contrast,the bothersome degree caused by focusing difficulty(p=0.046)and the frequency of difficulty in judging distance or depth perception(p=0.046)were better when wearing MFSCLs than when wearing single vision spectacle lenses.Compared with the naked eye,MFSCLs increased the total aberrations(p<0.001),higher-order aberrations(p<0.001),trefoil(p=0.023),coma aberrations(p<0.001)and spherical aberrations(SA)(p<0.001).Compared with the SVSCLs,MFSCLs increased the total aberrations(p<0.001),higher-order aberrations(p<0.001),coma aberrations(p<0.001)and SA(p<0.001).The direction of SA was more positive(p<0.001)with the MFSCLs and more negative(p=0.001)with the SVSCLs compared with the naked eye.Conclusions:Wearing MFSCLs can provide satisfactory corrected visual acuity(both distance HCVA and distance LCVA).Although the lenses increased the aberrations,such as total aberrations and higher-order aberrations,there were few adverse effects on the distance HCVA,distance LCVA and visual perception after 1 month of MFSCL use.

Visual quality of juvenile myopes wearing multifocal soft contact lenses

Background:It is unclear whether multifocal soft contact lenses(MFSCLs)affect visual quality when they are used for myopia control in juvenile myopes.The aim of this study was,therefore,to investigate the effect of MFSCLs on visual quality among juvenile myopia subjects.Methods:In a prospective,intervention study,33 juvenile myopes were enrolled.Visual perception was assessed by a quality of vision(QoV)questionnaire with spectacles at baseline and after one month of MFSCL wear.At the one month visit,the high(96%)contrast distance visual acuity(distance HCVA)and low(10%)contrast distance visual acuity(distance LCVA)were measured with single-vision spectacle lenses,single-vision soft contact lenses(SVSCLs)and MFSCLs in a random order.Wavefront aberrations Were measured with SVSCLs,MFSCLs and,without anycorrection.Results:Neither distance HCVA(P>0.05)nor distance LCVA(P>0.05)revealed any significant difference between MFSCLs,SVSCLs and single-vision spectacle lenses.The overall score(the sum of ten symptoms)of the QoV questionnaire did not show a statistically significant difference between spectacles at baseline and after one month of MFSCL wear(P=0.357).The results showed that the frequency(P<0.001),severity(P=0.001)and bothersome degree(P=0.016)of halos were significantly worse when wearing MFSCLs than when wearing single-vision spectacle lenses.In contrast,the bothersome degree caused by focusing difficulty(P=0.046)and the frequency of difficulty in judging distance or depth perception(P=0.046)were better when wearing MFSCLs than when wearing single-vision spectacle lenses.Compared with the naked eye,MFSCLs increased the total aberrations(P<0.001),higher-order aberrations(P<0.001),trefoil(P=0.023),coma aberrations(P<0.001)and spherical aberrations(SA)(P<0.001).Compared with the SVSCLs,MFSCLs increased the total aberrations(P<0.001),higher-order aberrations(P<0.001),coma aberrations(P<0.001)and SA(P<0.001).The direction of SA was more positive(P<0.001)with the MFSCLs and more negative(P=0.001)with the SVSCLs compared with the naked eye.Conclusions:Wearing MFSCLs can provide satisfactory corrected visual acuity(both distance HCVA and distance LCVA).Although the lenses increased the aberrations,such as total aberrations and higher-order aberrations,there were few adverse effects on the distance HCVA,distance LCVA and visual perception after one month of MFSCL Wear.