A comparison of posterior capsular opacification after implantation of three different hydrophobic square edge intraocular lenses

Objective quantification of posterior capsule opacification after cataract surgery with swept-source optical coherence tomography

PURPOSE

To evaluate the application of swept-source optical coherence tomography (SS-OCT) and pentacam scheimpflug tomography in posterior capsule opacification (PCO) severity assessment.

METHODS

The posterior capsule image region segmentation and adaptive threshold algorithm are used to process the SS-OCT scanned image to obtain the posterior capsule thickness (PCT). Scheimpflug tomography reconstructed and analysized by image J software can obtain the average gray value and evaluate the effectiveness with the two methods.

RESULT

One hundred sixty-two IOL eyes of 101 patients were divided into two groups, laser group (65 eyes) with the mean PCT was 8.0 ± 2.7 pixel unit and the mean gray value of the eyes was 66 ± 33 pixel unit. However, these figures in the control group (97 eyes) were 5.0 ± 0.9 and 11 ± 17. The sensitivity, specificity and area under curve(AUC) of SS-OCT PCT were 85%, 74% and 0.942,the sensitivity, specificity and AUC of Pentacam gray value were 91%, 76% and 0.947, respectively. After using the multivariable model of generalized estimation equation to corrected the dependence of subjects' eyes, it was found that SS-OCT PCT, Pentacam gray value, low vision quality of life questionnaire (LVQ questionnaire) for distance vision, and mobility and lighting dimension were significantly correlated with the PCO score (P = 0.012, P = 0.001, P = 0.005, respectively).

CONCLUSION

The region segmentation and adaptive threshold algorithm of posterior capsule image will accurately quantify the posterior capsule. Computer aided quantifications of posterior capsule are of great significance in the early surgical decision-making of PCO. The average occurrence time of most PCO was around 34 months, and the severity of PCO worsened with increasing postoperative time.

Should We Abandon Hydrophilic Intraocular Lenses?

PURPOSE

To characterize the features of hydrophilic intraocular lenses (IOLs) important in the clinical context of expected prolonged duration time of the IOL within the eye.

DESIGN

Perspective.

METHODS

Discussion includes possible factors and mechanisms associated with hydrophilic IOLs' susceptibility to calcification and posterior capsule opacification (PCO) formation.

RESULTS

Results of recently reported studies show that particular surgeries, such as pars plana vitrectomy, Descemet stripping (automated) endothelial keratoplasty, and Descemet membrane endothelial keratoplasty with intraocular gas or air injection, might predispose the calcification process of hydrophilic IOLs, leading to a significant decrease in visual quality and possibly explantation of the IOL. Hydrophilic IOLs are more susceptible than hydrophobic IOLs to PCO formation, which is the most common of late postoperative complications that are associated with significant side effects.

CONCLUSIONS

We believe that all patients should be informed about the higher risk of calcification and PCO associated with hydrophilic IOLs. We also recommend limiting the use of hydrophilic acrylic IOLs during cataract surgery, especially when it is combined with pars plana vitrectomy or endothelial keratoplasty, and in patients with endothelial diseases who will probably require operation on it in the future.

Posterior capsular vacuuming to avoid PCO formation

AIM

To retrospectively evaluate the effectiveness of the capsular vacuuming technique in reducing posterior capsule opacification (PCO).

METHODS

Group 1 of the study consisted of 2752 eyes of 2752 patients with a cataract who had undergone phacoemulsification and IOL implantation surgery with anterior, equatorial, and posterior capsular polishing between January 2010 and December 2014. Group 2 consisted of 2761 eyes of 2761 patients with a cataract who had undergone phacoemulsification and IOL implantation surgery with anterior, equatorial, and posterior capsular polishing as well as posterior capsular vacuuming between January 2010 and December 2014.

RESULTS

The mean patient age was 63.45 ± 12.23 years (range, 43-89) in Group 1 and 64.02 ± 13.36 years (range, 40-91) in Group 2. The two groups did not significantly differ with respect to age, sex, preoperative and postoperative uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and intraocular pressure (IOP) measurements (p > 0.05). At the 5-year follow-up, 253 eyes (9.19%) in Group 1 developed PCO requiring Nd:YAG laser capsulotomy, whereas 24 eyes (0.86%) in Group 2 developed PCO requiring Nd:YAG laser capsulotomy (p < 0.001). During capsular vacuuming, posterior capsule rupture was observed in the shape of a hole in only 2 eyes in Group 2. But the IOLs were implanted in the capsular bag in all eyes in both groups.

CONCLUSION

PCO is the most common complication of cataract surgery; therefore, surgical technique is important in preventing PCO formation. We recommend posterior capsular vacuuming together with anterior, equatorial, and posterior capsular polishing, as this method significantly reduced the PCO rate.

The Influence of Inflammation in Posterior Capsule Opacification Development

Cataract represents the reduction of the transparency of the crystalline lens. Cataract surgery is the most commonly performed surgical procedure worldwide. One of the most common postoperative complication of successfully performed cataract surgery is a development of posterior capsule opacification (PCO). In the postoperative period, lens epithelial cells (LECs) undergo proliferation, migration and differentiation, which is clinically manifested by the development of PCO. Inflammation has a central role in these processes. Cytokines, such as transforming growth factor β, fibroblast growth factor, interleukin 1, interleukin 6, matrix metalloproteinases have a huge effect on the activity of LECs. Understanding these processes can find a great usage in clinical practice. By prescribing anti-inflammatory therapy in the early postoperative period, the incidence of PCO can be significantly reduced.

Long-Term Clinically Significant Posterior Capsular Opacification Development Pattern in Eyes Implanted with an Aspheric Monofocal Intraocular Lens with a Square Optic Edge

Purpose

To analyse the posterior capsular opacification (PCO) development pattern in the long term in eyes implanted with a monofocal intraocular lens (IOL) with a square edge all around the optic.

Methods

Longitudinal retrospective study is data analyzed from a total of 7059 eyes from 4764 patients (mean age: 75.8 years) undergoing cataract surgery with implantation of an aspheric monofocal IOL (Bi-Flex HL 677AB/677P, Medicontur, Budapest, Hungary). These data were retrospectively collected using the electronic medical record of the hospitals involved. Nd : YAG capsulotomy rates were calculated per year during a follow-up of more than 10 years. The Kaplan–Meier analysis was used to establish the transparent capsule survival rate.

Results

The Nd : YAG capsulotomy rate increased from 1.1% at 1 year postoperatively to 17.2% at 5 years after surgery. No significant differences were found between eyes with and without capsulotomy in terms of age (p = 0.202), gender (p = 0.061), type of anaesthesia used (p = 0.128), and presence of conditions such as hard cataract (p = 0.111) or pseudoexfoliation (p = 0.137). IOL power was significantly lower in those eyes of patients requiring Nd : YAG capsulotomy during the follow-up (p < 0.001). Significantly more eyes implanted with the preloaded model of the IOL required capsulotomy (p < 0.001). Mean survival time and rate were 9.38 years and 85.9%, respectively.

Conclusions

Most eyes undergoing cataract with implantation of the Bi-Flex IOL do not develop a clinically significant PCO requiring Nd : YAG capsulotomy in the long term. IOL material and design may be the main factors accounting for this finding.

Anterior segment OCT application in quantifying posterior capsule opacification severity with varied intraocular lens designs

AIM

To evaluate the application of anterior segment-optical coherence tomography (AS-OCT) in posterior capsule opacification (PCO) severity assessment and analyse the relationship between PCO severity and intraocular lens (IOL) characters.

METHODS

PCO patients were prospectively recruited. Cross-sectional images of the anterior segment at horizontal and vertical meridians were acquired with AS-OCT. The area of the IOL-PC (posterior capsular) space and PCO severity (area, thickness, and density at 3 mm and 5 mm IOL optic regions) were measured. The relationship between PCO severity and visual acuity, comparisons of PCO severity and IOL-PC space using varied IOL designs were analysed.

RESULTS

One hundred PCO eyes were enrolled. IOL-PC space, PCO thickness and area were positively correlated with axial length. In addition, PCO area and thickness were positively correlated with visual acuity when it was ≤0.52 logMAR. The cut-off level of visual acuity should be 0.52 logMAR. With varied IOL designs, 3-piece C haptic IOL showed a smaller PCO area and thickness than the 1-piece 3 haptic IOL and 1-piece 4 haptic IOL. PCO area and thickness values for an IOL with a diameter ≤11.0 mm was greater than for an IOL with a diameter of 12.5 mm, and the differences were statistically significant. PCO area and thickness increased when IOL haptic angulation increased (from 0 to 12 degrees).

CONCLUSION

In PCO eyes, cut-off level of visual acuity is 0.52 logMAR. With more severe PCO, visual acuity maybe not enough to describe the visual function impairment. PCO severity and IOL-PC space are significantly correlated with axial length and IOL design and material.