IOLs, OCT and congenital cataracts

October 7, 2013

Review of the third day of ESCRS 2013.

Post-op IOL positioning independent of rhexis size and shape


Modern IOLs offer precise capsulotomy, with the postoperative capsular bag positioning, in terms of tilt, decentration and postoperative anterior chamber depth, appearing to be relatively independent of the shape and size of the capsulorhexis opening, reported Professor Oliver Findl (VIROS [Vienna Institute for Research in Ocular Surgery], Hanusch Hospital, Vienna, Austria) during a free paper session this morning.
Professor Findl and his team performed a continuous cohort study of 300 eyes undergoing cataract surgery performed by 9 different surgeons of varying levels of experience, who implanted 3 different models of modern, acrylic IOLs and then assessed eyes one hour and 3 months after surgery for anterior chamber depth, rhexis openings and (at 3 months only) tilt and decentration.
Preliminary results of the first 100 eyes showed a mean tilt and decentration of 3.8° (SD: 2.1) and 0.4 mm (SD: 0.2), respectively. Mean rhexis diameter 1 hour and 3 months postoperatively was 4.76 mm (SD: 0.5) and 4.89 mm (SD: 0.48), respectively. Mean rhexis shape factor (RSF; analysed using the rhexis mode of the AQUA software) was 0.27 mm (SD: 0.13) and 0.24 mm (SD: 0.10) at 1 hour and 3 months, respectively, which was a significant change (p=0.046); correlations between RSF and tilt, and between RSF and decentration, were weak, and tilt and decentration were not significantly different between normal cases and those in which no rhexis overlap with the IOL was observed (18 cases).
"This shows that the postoperative capsular bag positioning of these modern, acrylic IOLs is not significantly affected by the shape or size of the capsulorhexis opening," Professor Findl concluded.

Real time OCT advantageous in femtosecond cataract surgery


"Real-time OCT is very helpful during the fast and delicate femtosecond laser cataract surgery procedure, as it can allow the surgeon to detect, evaluate and (if necessary) adjust elements of the procedure or the patient's position, increasing surgeon comfort because it allows for real-time awareness of the surgical outcome," said Dr Roberto Bellucci (Hospital of Verona, Verona, Italy). "Although soft docking can minimize the negative effects of the laser on the cornea, it does not prevent small movements of the patient or the eye, meaning that potential problems in procedure efficacy and safety remain."
To address this, Dr Bellucci and his colleague Dr Miriam Cargnoni used periprocedural real-time OCT during cataract treatment of 50 eyes with the VICTUS femtosecond laser (Technolas Perfect Vision; Munich, Germany), recording intraoperative complications and inconveniences, as well as surgeon comfort. They found that real-time OCT allowed the surgeon to monitor the procedure more closely by being able to compare OCT images with camera images, and therefore potential problems were able to be addressed as the procedure progressed.
"In one eye, a small fluid bubble was noted before surgery between the corneal surface and the patient interface, suggesting re-docking," noted Dr Bellucci. "The peripheral fluid meniscus showed changes in two eyes during the procedure, and was corrected by lateral shifting of the bed."
"Patients were assessed at their 6-week postoperative visit for evidence of dry eye using SPK grading," said Mr Corkin.
Surgeons felt more comfortable because of this increased awareness of potential surgical complications and outcomes.

Careful surgical approach to congenital cataract gives good results


"Although treatment for congenital cataract in paediatric patients is challenging and can be associated with the development of deprivation amblyopia, strabismus, nystagmus and glaucoma, a careful surgical approach with primary IOL implantation, even in infants, has shown good intra- and postoperative results," Dr Catarina Pedrosa (Fernando Fonseca Hospital, Lisbon, Portugal) and colleagues reported this evening.
The team presented a series of paediatric eyes (age range: 8 weeks to 4 years) undergoing unilateral (n=7) or bilateral (n=3) micro-incision phacoemulsification. To increase the stability of the anterior chamber, anterior capsulorrhexis was performed before the main incision in all patients; primary posterior capsulotomy and anterior vitrectomy were also undertaken, to reduce the prevalence of posterior capsule opacification, and preservative-free triamcinolone acetonide was injected intracamerally, to reduce anterior segment inflammation and improve vitreous visualization. Corneal main incision and side-ports were closed with non-reabsorbable sutures.
In most cases, the primary implantation was of an acrylic, hydrophobic 3-piece posterior chamber IOL with optic capture. In 2 cases, the IOL was implanted in the ciliary sulcus because of insufficient capsular support in the bag. However, no other major intraoperative complications were reported.
The mean values of Pentacam automated and manual measurements were 11.77 mm (range: 10.6–12.6 mm) and 11.74 mm (range: 10.4–12.5 mm) the mean values of Orbscan automated and manual measurements were 11.68 mm (range: 10.4–13.0 mm) and 11.66 mm (range: 10.4–12.5 mm).
"Postoperative complications consisted of iris synechiae in 2 patients, one with the need of re-intervention for synechiolysis, and inflammatory reaction to the corneal suture in all cases, which resolved with the suture extraction. Intracameral triamcinolone injection intraoperatively did not affect intraocular pressure and no other adverse postoperative results were observed," said Dr Pedrosa. "This shows that such a careful approach to primary IOL implantation can produce good results, both intra- and postoperatively."

Customized IOLs can produce good VA


Customized IOLs can produce good visual acuity and high visual quality even in eyes with astigmatism, those with spherical aberration due to keratoconus or in those that have undergone previous surgical treatment for refractive issues. This was the conclusion of Dr G Parisi (University of Verona, Verona, Italy) and colleagues, who presented a free paper detailing their study of 16 eyes with either non-evolutive keratoconus (n=10) or previous refractive laser treatment (n=6).
Each of the eyes was implanted with an IOL customized to its specific spherical and toric power and spherical aberration. Follow-up examinations, which were performed 6 months postoperatively, assessed visual acuity (at near [40 cm] and distance), aberrometry and contrast sensitivity.
At follow-up, mean uncorrected visual acuity (UCVA) was 0.63±0.21 D and mean best-corrected visual acuity (BCVA) was 0.89±0.32 D, with a refractive error of -0.52±0.67 D compared with preoperative target. Near UCVA was 0.65±0.14 D, increasing to 0.97±0.19 D with correction. Contrast sensitivity was normal, and total spherical aberration was 0.01 µm.
"This shows that using an IOL customized to the patient’s exact eye can produce good visual outcomes even in patients that are not traditionally good candidates for this procedure, including those with astigmatism, keratoconus or previous refractive laser treatment," concluded Dr Parisi.