Further Enhancement of Intraocular Open-Capsule Devices for Prevention of Posterior Capsule Opacification

Influence of the CleaRing intraocular open capsule device on refractive predictability in cataract surgery

BACKGROUND

The marked improvement in cataract surgery and intraocular lens (IOL) quality has led to a decline in posterior capsular opacification (PCO) incidence; however, PCO remains a common complication of cataract surgery. The CleaRing intraocular capsule open device (IOCD) decreases PCO incidence. We aimed to investigate the influence of the CleaRing IOCD on refractive predictability in cataract surgery.

METHODS

We conducted this prospective pilot study at the Wolfson Medical Center, Holon, Israel. Ten eyes of patients who underwent cataract surgery and insertion of an IOL after IOCD implantation into the capsular bag were included. All patients completed 12 months of follow-up, including refraction, measurement of uncorrected (UDVA) and best-corrected distance visual acuity (CDVA), slit-lamp biomicroscopy, and ultrasound biomicroscopy.

RESULTS

All the surgeries were uneventful, with no postoperative complications. The IOL was centred in the device and bag in all cases. The mean prediction error at 1 and 12 months postoperatively was +0.28 ± 0.32 D and +0.50 ± 0.32 D, respectively. The mean UDVA was 0.17 ± 0.13 and 0.15 ± 0.11 logMAR, and the mean CDVA was 0.04 ± 0.10 and 0.04 ± 0.06 logMAR, respectively. The manifest refractive cylinders at 12 months postoperatively were compatible with corneal astigmatism.

CONCLUSIONS

Implantation of the IOCD resulted in a slight, predicted, and stable hyperopic shift with a low standard deviation. The standard deviation of the prediction error demonstrated excellent refractive accuracy and predictability using the IOCD, which was as low as 0.32 D at the 12-month follow-up.

Factors Affecting Posterior Capsule Opacification in the Development of Intraocular Lens Materials

Posterior capsule opacification (PCO) is the most common complication arising from the corrective surgery used to treat cataract patients. PCO arises when lens epithelial cells (LEC) residing in the capsular bag post-surgery undergo hyper-proliferation and transdifferentiation into myofibroblasts, migrating from the posterior capsule over the visual axis of the newly implanted intraocular lens (IOL). The developmental pathways underlying PCO are yet to be fully understood and the current literature is contradictory regarding the impact of the recognised risk factors of PCO. The aim of this review is firstly to collate the known biochemical pathways that lead to PCO development, providing an up-to-date chronological overview from surgery to established PCO formation. Secondly, the risk factors of PCO are evaluated, focussing on the impact of IOLs’ properties. Finally, the latest experimental model designs used in PCO research are discussed to demonstrate the ongoing development of clinical PCO models, the efficacy of newly developed IOL technology, and potential therapeutic interventions. This review will contribute to current PCO literature by presenting an updated overview of the known developmental pathways of PCO, an evaluation of the impact of the risk factors underlying its development, and the latest experimental models used to investigate PCO. Furthermore, the review should provide developmental routes for research into the investigation of potential therapeutic interventions and improvements in IOL design in the aid of preventing PCO for new and existing patients.

Posterior capsule opacification: What's in the bag?

Cataract, a clouding of the lens, is the most common cause of blindness in the world. It has a marked impact on the wellbeing and productivity of individuals and has a major economic impact on healthcare providers. The only means of treating cataract is by surgical intervention. A modern cataract operation generates a capsular bag, which comprises a proportion of the anterior capsule and the entire posterior capsule. The bag remains in situ, partitions the aqueous and vitreous humours, and in the majority of cases, houses an intraocular lens (IOL). The production of a capsular bag following surgery permits a free passage of light along the visual axis through the transparent intraocular lens and thin acellular posterior capsule. Lens epithelial cells, however, remain attached to the anterior capsule, and in response to surgical trauma initiate a wound-healing response that ultimately leads to light scatter and a reduction in visual quality known as posterior capsule opacification (PCO). There are two commonly-described forms of PCO: fibrotic and regenerative. Fibrotic PCO follows classically defined fibrotic processes, namely hyperproliferation, matrix contraction, matrix deposition and epithelial cell trans-differentiation to a myofibroblast phenotype. Regenerative PCO is defined by lens fibre cell differentiation events that give rise to Soemmerring's ring and Elschnig's pearls and becomes evident at a later stage than the fibrotic form. Both fibrotic and regenerative forms of PCO contribute to a reduction in visual quality in patients. This review will highlight the wealth of tools available for PCO research, provide insight into our current knowledge of PCO and discuss putative management of PCO from IOL design to pharmacological interventions.

Anti-inflammatory Medication After Cataract Surgery and Posterior Capsular Opacification

PURPOSE

To assess the role of anti-inflammatory medication following cataract surgery on the formation of posterior capsular opacification.

DESIGN

Cohort study.

METHODS

A retrospective registry analysis of 25,818 consecutive patients who underwent cataract surgery between the years 2014 and 2018 at Helsinki University Hospital in Finland. Nd:YAG laser capsulotomy rates were compared between patients treated postoperatively with topical steroids, nonsteroidal anti-inflammatory medications (NSAIDs), or their combination. Kaplan-Meier and Cox regression analyses were used. A single eye of each patient was included. Main outcomes were confirmed against a second independent dataset.

RESULTS

A total of 13,368 patients were included in the analysis, with a mean age of 73.2 ± 9.7 years; 61.7% were female. Pseudoexfoliation was noted in 10.1% of cases. The mean follow-up time was 22.8 ± 15.7 months. Patients were treated with steroid monotherapy (28.9% of cases), NSAID monotherapy (62.2%), or a combination of both (8.9%). Treatment with steroids resulted in significantly lower Nd:YAG capsulotomy rates compared to NSAIDs (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.62-0.93, P = .009). Treatment with combination therapy of steroids and NSAIDs showed no added benefit over steroid monotherapy (HR 1.11, 95% CI 0.68-1.80, P = .674). Cox regression analysis adjusted for patients' age, sex, pseudoexfoliation, and risk stratification remained significantly predictive for lower capsulotomy rates with steroid treatment over NSAIDs (HR 0.70, 95% CI 0.52-0.88, P = .001).

CONCLUSIONS

Postoperative treatment with steroids among patients undergoing uncomplicated cataract surgery was associated with lower rates of clinically significant posterior capsule opacification compared to treatment with NSAIDs alone. Combination therapy of steroids and NSAIDs had no added benefit over steroids alone.