To investigate the clinical features, surgical treatment and its effectiveness and of late-onset capsular block syndrome (LCBS).

A total of 12 patients (12 eyes) diagnosed with LCBS were enrolled from January 2007 to June 2022 at Department of Ophthalmology of Xijing Hospital, Air Force Medical University. All 12 cases (12 eyes) were detected and diagnosed by slit-lamp microscope after dilating pupils. In order to clarify the location of the capsular bag and intraocular lens (IOL), 8 cases (8/12) were performed by the ultrasound biomicroscopy. All the enrolled patients underwent releasing the adhesion of the anterior capsular ring combined with fluid aspiration in the capsular bag. The complete data of the patients were collected, including gender, age, laterality, onset time, clinical features, IOL type, and other ocular medical histories. The visual acuity, intraocular pressure (IOP) and refraction before and after surgery were examined and documented, and intraoperative and postoperative complications were recorded. All of the above clinical measurement data were described using frequencies and percentages. Age, axial length, postoperative time to capsular bag block syndrome, preoperative anterior chamber depth and distance between the posterior capsule and the IOL conformed to normal distribution through Shapiro-Wilk test, and were described by±s.

The onset of LCBS ranged from 2 to 10 years after cataract surgery, with an average period of (5.00±2.37) years. The visual acuity loss was the main symptom, with preoperative best corrected visual acuity (BCVA) ranging from countfigures to 0.8, with a median value of 0.2 (0.05, 0.55); the diopter of all patients was -5.00 D to + 2.75 D with a median value of -2.31(-3.50, 0.125)D. IOP of all patients ranged from 9 to 22 mmHg (1 mmHg=0.133 kPa), with an average value of (15.3±3.98) mmHg. Axial length was 20.8 to 32.63 mmwith an average value of (25.45±3.87) mm; and the anterior chamber depth ranged from 2.90 to 4.86 mm, with an average value of (3.36±0.69) mm. A total of 6 cases (6 eyes) were combined with high myopia before surgery, accounting for 50% (6/12). Nine cases (9 eyes) had three-piece foldable C-loop hydrophobic IOL and 3 cases (3 eyes) had two-loop or four-loop hydrophilic IOL without the angle to the posterior capsule, accounting for 75% (9/12) and 25% (3/12), respectively. There were 10 cases (10 eyes) with visual acuity improved on the 1^st postoperative day compared with the preoperative, and 2 cases (2 eyes) decreased after surgery, accounting for 83% (10/12) and 17% (2/12), respectively. Postoperative IOP ranged from 8 to 19 mmHg, with an average value of (15.0±3.03) mmHg. The changes of postoperative refraction were from -4.25 D to + 2.00 D, with a median value of -1.00 (-2.13, 0.563) D. There were not observed serious intraoperative or postoperative complications.

The onset of LCBS is insidious, and its primary clinical manifestation is mild visual acuity loss, with no apparent IOP increase and myopia shift. Patients with high myopia are prone to LCBS after cataract surgery, and LCBS can occur with IOLs of various designs and materials. Adhesion of anterior capsular ring releasing combined with fluid aspiration in the capsular bag is an effective and safe surgical treatment for severe LCBS.