Causes of hyperopic shift of late-onset capsular block syndrome presenting with posterior capsule opacification

Abstract

Objective To investigate the clinical causes of hyperopic shift of late-onset capsular block syndrome(CBS) presenting with posterior capsule opacification (PCO).Methods Eight cases (9eyes) of late-onset CBS presenting with PCO were studied,who accepted Nd:YAG laser capsulotomy.Before and after laser surgery,all patients were examined by auto-refractometer,comprehensive optometry,A/B scan,ultrasound biomicroscope (UBM) and slit-lamp biomicroscopy of anterior eye segment.The central anterior chamber depth was determined by UBM.Results All eyes showed moderate to high hyperopia with average diopter(4.86 ± 1.77) D,and the average central anterior chamber depth was (3.48 ± 0.44) mm.During the Nd:YAG laser posterior capsulotomy procedure,the milk liquid spreaded diffusely and mixed into the vitreous body.After Nd:YAG capsulotomy,all cases showed light myopic to light hyperopic condition with average diopter(0.11 ± 0.67)D and the central anterior chamber depth increased to (4.21 ± 0.27)mm.Conclusion The milk liquid in capsule bag of late-onset CBS with PCO has refractive power,and that can counteract myopic shift produced by preposition of intraocular lens and cause hyperopic condition. Key words: Syndrome, capsular block; Opacification, posterior capsular; Shift, hyperopic ; Shift,myopic