Early Postoperative Capsular Block Syndrome Following Cataract Surgery With Trifocal Iol Implantation: A Case Report

Achieving a predictable refractive outcome is of major importance in the context of modern cataract surgery, more so with the use of trifocal intraocular lenses (IOLs). Although rare, refractive surprises are particularly troublesome when spectacle independence is expected. The aim of this case report is to describe the occurrence and management of early postoperative capsular block syndrome in a 51-year-old woman submitted to phacoemulsification with posterior chamber trifocal IOL implantation.

Department of Ophthalmology, Unidade Local de Saúde de Matosinhos, Portugal

A previously healthy 51-year-old woman was diagnosed with progressive bilateral posterior subcapsular cataracts. Due to severe visual impairment - the preoperative best-corrected visual acuity (BCVA) was logMAR 1.0 OU -, she underwent uneventful phacoemulsification with subsequent insertion of a +16.0D RayOne Trifocal (Rayner, Worthing, UK) IOL in her left eye. Of note, optical biometry (IOL Master 700, Carl Zeiss, Jena, Germany), revealed an axial length (AL) of 25.28 mm and 25.49 mm in her right and left eye, respectively. On the postoperative day, she complained of near-sightedness. Slit-lamp examination revealed an anterior shift of the IOL-bag complex (ACD 3.40mm), as well as an anterior position of the IOL within an abnormally distended bag. BCVA was logMAR 0.1 with -2.00D. We opted for a watchful waiting approach during the first two weeks, after which there was no meaningful clinical improvement. Accordingly, we performed Nd:YAG posterior capsulotomy, with immediate egress of clear capsular fluid towards the vitreous cavity and a posterior shift of the IOL within the bag (ACD 4.37mm). The patient reported immediate improvement of distance VA (logMAR 0.2) following the procedure. Three weeks post-capsulotomy, the patient reported no visual complaints and achieved a distance uncorrected VA of logMAR 0.0, as well as near uncorrected VA of logMAR 0.1. 

Early postoperative capsular block syndrome, a rare complication of phacoemulsification, involves anteriorization of the IOL with retrolenticular fluid accumulation and bag distension. Clinically, the abnormal anterior lens position is responsible for a myopic refractive surprise. Factors such as above-average AL (i.e., larger bag), coupled with the hydrophilic nature of the IOL might have contributed to this outcome. Besides, despite thorough aspiration, we cannot completely exclude the existence of residual viscoelastic retained behind the lens. This condition can be effectively managed through Nd:YAG posterior capsulotomy, with release of accumulated fluid into the vitreous cavity, producing an almost immediate repositioning of the IOL.