Quantitative Effects Of Posterior Capsule Opacification On Subjective And Objective Visual Quality

Objective: To evaluate the repeatability and stability of the posterior capsule opacification index measured by ARK-1s automatic computer optometry /corneal curvature instrument,and to quantitatively study the effect of posterior capsule opacification on the subjective and objective visual quality.Methods: Twenty-seven PCO patients who were about to undergo Nd:YAG laser posterior capsule resection were collected.After detailed eye examination,the pupils were fully dilated.ARK-1s was used to measure the posterior capsule opacity index(COI.H,COI.A,POI).The repeatability and stability were assessed using intra-group correlation coefficient(ICC)and variation coefficient(CV)as statistical indicators.At the same time,the uncorrected visual acuity(UCVA),best correct visual acuity(BCVA),objective scattering light index(OSI),log(S)value,total higher-order aberration,coma,spherical aberration,trefoil aberration,strehl ratio(SR),modulation transfer function cut off(MTF cutoff)under natural pupil and after dialated of all patients before and one week after operation were measured.To analyze the correlation between the changes of posterior capsular turbidity area and subjective and objective visual quality before and after posterior capsular resection with Nd:YAG laser.Results: 1.There was no significant difference in the results of the three measurements of COI.H,COI.A and POI(F=0.041,P>0.05;F = 0.378,P > 0.05;F=0.930,P>0.05),ICC was greater than 0.8,CV was less than 5%;2.After Nd:YAG laser surgery,? COI.A is corerelated with ? COI.H,? UCVA,? BCVA,? OSI,? SR(3 mm pupil),? SR(6 mm pupil),? MTF cutoff(3 mm pupil),? MTF cutoff(6 mm pupil),? log(S)value(3 mm pupil),? log(S)value(6 mm pupil),?HO Total aberrations(3 mm pupil),?HO Total aberrations(6 mm pupil),? coma(3 mm pupil),? coma(6 mm pupil),?spherical aberration(3 mm pupil),? spherical aberration(6 mm pupil),? trefoil aberrations(3 mm pupil),? trefoil aberrations(6 mm pupil)(?r?= 0.431 ~ 0.904,P <0.05).Among them,? COI.A is strongestly correlated with ? BCVA and ? OSI(r =0.904,P < 0.05;r = 0.891,P < 0.05),but has no correlation with ? POI(r = 0.231,P >0.05).Conclusion: 1.In the opacity index measured by ARK-1s automatic computer optometry/keratometer,COI.H and COI.A can assist in the clinical evaluation of PCO;2.Posterior capsule opacification area has an influence on UCVA(logMAR),BCVA(logMAR),OSI,log(S),HO Total aberration,coma,spherical aberration,trefoil aberration,SR,MTF cutoff,among which BCVA and OSI are mostly affected.The larger the turbidity area is,the smaller the SR and MTF cutoff are,the lower the UCVA and BCVA are,and the larger the high-order aberration and the intraocular scattering are.