The enVista IOL label states that no glistenings of any grade were reported for any subject at any visit.13,14 However, published studies evaluating clinical outcomes (in particular, the incidence of PCO) with this lens are limited.
Consequently, we undertook a single-centre, prospective, observational clinical study to assess postoperative visual acuity and the incidence of PCO associated with this IOL in a group of pseudophakic patients.
Patients with against-the-rule or oblique astigmatism over 1.25 D, or with-the-rule astigmatism over 1.5 D, were implanted with a toric monofocal IOL. All other patients received an aspheric monofocal IOL.
In all cases, the IOL was implanted through a 2.2-mm clear corneal incision. All patients underwent at least four postoperative visits, at 24 hours, 1 week, 1 month and 12 months post-surgery.
Ninety-four eyes of 63 patients (mean age 74.5 ± 8.1 years) were included in the analysis. Of the 94 implanted lenses, 82 were aspheric monofocal and 12 were toric monofocal IOLs.
At a mean follow-up of 555.20 ± 34.04 days, there were statistically significant improvements in mean corrected distance visual acuity (CDVA) and spherical equivalent (all patients, P=0.000 and P=0.027, respectively). Overall, 92% of patients reached a postoperative CDVA of 0.1 logMAR (20/25 Snellen) or better. In the toric and aspheric groups, respectively, 100% and 88.6% of patients had a visual acuity of 0.1 logMAR (20/25 Snellen) or better.
Glistenings were not observed via slit lamp imaging or following an analysis of retroillumination images in any of the implanted lenses in any patient or at any follow-up visit. Capsulotomy was performed when vision was insufficient for patients and following image analyses.
Overall, 5.3% eyes implanted with the lens required Nd:YAG laser posterior capsulotomy. Of these patients, 80% reported a progressive loss of vision, whereas 20% reported no symptoms but chose to undergo capsulotomy due to the presence of Elschnig pearls in the visual axis. Nd:YAG capsulotomy was required at 9 months postoperatively in 20% of eyes and at 18 months postoperatively in 40% of eyes; 40% of eyes showed opacification at 25 months postoperatively and were treated with Nd:YAG at this time.
The mean CDVA (logMAR) in patients requiring Nd:YAG laser posterior capsulotomy was 0.10 ± 0.08 (range 0.05–0.22) before the procedure and 0.01 ± 0.04 (range 0.0–0.09) after the procedure – a statistically significant improvement in visual acuity (P=0.0021).
The toric lens also had good rotational stability: the mean rotation of the toric IOL during the first 24 hours post-surgery (versus preoperative calculated IOL position) was 2.0 ± 1.3Ë (range 0–5). The mean IOL rotation was 2.1 ± 1.03Ë (range 0–4) and 2.0 ± 0.95Ë (range 0–4) 1 week and 30 days post-surgery, respectively.