Clinical and experimental study of late postoperative opacification of hydrophilic acrylic intraocular lenses

Objective: To analyze the cause of late postoperative opacification of hydrophilic acrylic intraocular lenses (IOLs) and the effect of IOL replacement surgery. Methods: This retrospective case series study comprised 15 eyes of 15 patients who were diagnosed as late postoperative opacification of hydrophilic acrylic IOLs from January 2019 to June 2020 at Qingdao Eye Hospital of Shandong First Medical University. The clinical data of patients were reviewed, and two IOLs were examined by scanning electron microscopy and energy dispersive X-ray spectroscopy. The intraoperative and postoperative complications of IOL replacement surgery were evaluated, and best corrected visual acuity was compared before and after surgery. Preoperative and postoperative data were compared using the paired t test. Results: The interval between the first IOL implantation and the detection of IOL opacification in 15 patients was (27.3±5.9) months. All the 15 patients had unilateral IOL opacification, and 9 patients had hypertension. Glycosylated hemoglobin A1c was significantly higher than the normal value in 4 of the 10 patients who underwent cataract surgery at our hospital. Confocal microscopy disclosed coralliform deposits on the superficial IOL optic. Scanning electron microscopy and energy dispersive X-ray spectroscopy showed the presence of calcium and phosphorus crystals in the opacification region of IOLs. Visual acuity in all 13 eyes receiving IOL exchange was significantly improved from 1.03±0.64 (logarithm of the minimum angle of resolution) to 0.39±0.21 (P<0.05). Posterior capsule rupture (4 eyes), new IOL implanted in the ciliary sulcus (3 eyes) and zonule breaking (1 eye) occurred during IOL replacement. Conclusions: IOL opacification is related with the IOL material and calcium ion concentration on the IOL surface. IOL replacement surgery can improve visual acuity safely and effectively. (Chin J Ophthalmol, 2021, 57: 512-518).