Anterior capsule opacification and lens epithelial outgrowth on the intraocular lens surface after curettage

Impact of anterior capsule polishing on capsule opacification and capsule bend after age-related cataract surgery

PURPOSE

To investigate the effect of anterior capsule polishing on postoperative capsule opacification and capsular bend in patients with age-related cataract displaying normal axial length.

SETTING

Eye Hospital of Wenzhou Medical University at Hangzhou.

DESIGN

Prospective self-controlled trial.

METHODS

Patients with age-related cataracts aged 56 to 84 years displaying normal axial length were enrolled. Before surgery, a coin-toss method was used to randomly select 1 eye for intraoperative 360 degrees anterior capsule polishing (polishing group); the contralateral eye received no treatment (control group). Capsular bend index (CBI), anterior capsule opacification (ACO), posterior capsule opacification (PCO), and anterior capsule opening area (ACOA) were recorded at 1 week, 1 month, 3 months, 6 months, and 12 months postoperatively using swept-source optical coherence tomography and slitlamp examination.

RESULTS

21 patients (42 eyes) were enrolled. Within-group comparisons showed that both groups had significant differences in CBI between 1 week and 1 month postoperatively, and between 6 months and 12 months postoperatively ( P < .05). Between-group comparisons revealed a significant difference in CBI at 1 week postoperatively ( P < .05); at 12 months postoperatively, there was a significant difference in ACOA ( P < .05). There were no significant between-group differences regarding ACO or PCO at any timepoint ( P > .05).

CONCLUSIONS

For patients with age-related cataracts and normal axial length, 360 degrees anterior capsule polishing can delay early capsular bag deformation without increasing the risks of ACO and PCO. This approach can also limit contraction of the anterior capsule opening.

MiR-22-3p inhibits fibrotic cataract through inactivation of HDAC6 and increase of α-tubulin acetylation

OBJECTIVES

Fibrotic cataract, including posterior capsule opacification (PCO) and anterior subcapsular cataract (ASC), renders millions of people visually impaired worldwide. However, the underlying mechanism remains poorly understood. Here, we report a miRNA-based regulatory pathway that controls pathological fibrosis of lens epithelium.

MATERIALS AND METHODS

Expression of miR-22-3p and histone deacetylase 6 (HDAC6) in normal and PCO patient samples were measured by qPCR. Human lens epithelial explants were treated with TGF-β2 in the presence or absence of miR-22-3p mimics or inhibitor. Cell proliferation was determined by MTS assay, and migration was tested by transwell assay. Expression of HDAC6 and EMT-related molecules were analysed by Western blot, qPCR and immunocytochemical experiments.

RESULTS

We identify miR-22-3p as a downregulated miRNA targeting HDAC6 in LECs during lens fibrosis and TGF-β2 treatment. Mechanistically, gain- and loss-of-function experiments in human LECs and lens epithelial explants reveal that miR-22-3p prevents proliferation, migration and TGF-β2 induced EMT of LECs via targeting HDAC6 and thereby promoting α-tubulin acetylation. Moreover, pharmacological targeting of HDAC6 deacetylase with Tubacin prevents fibrotic opaque formation through increasing α-tubulin acetylation under TGF-β2 stimulated conditions in both human lens epithelial explants and the whole rat lenses.

CONCLUSIONS

These findings suggest that miR-22-3p prevents lens fibrotic progression by targeting HDAC6 thereby promoting α-tubulin acetylation. The 'miR-22-HDAC6-α-tubulin (de)acetylation' signalling axis may be therapeutic targets for the treatment of fibrotic cataract.

Advances in the Study of Lens Refilling

The ultimate goal of cataract surgery is to restore the accommodation while restoring distance visual acuity. Different kinds of accommodative intraocular lens (IOLs) and surgical techniques have been suggested to apply during the surgery, but they showed poor postoperative accommodation. It is possible to achieve this goal by refilling the lens with an injectable polymer. We present a summary of the existing materials, methods, results, and some obstacles in clinical application that remain of lens refilling for restoration of accommodation. Two main problems have restricted the clinical application of this technique. One was the formation of postoperative secondary capsule opacification and the other was the different accommodative power after surgery.

Proliferative Status in the Aqueous Humor of Eyes With Congenital Cataract

PURPOSE

To measure the concentrations of growth factors in the aqueous humor of patients with congenital cataract and to investigate the biological effects of a selected cytokine (fibroblast growth factor 4 [FGF4]) on cell proliferation, migration, and transformation.

METHODS

In the aqueous humor obtained from 55 eyes with congenital cataract and 55 eyes with age-related cataract, 40 growth factors were screened and selected cytokines were confirmed with enzyme-linked immunosorbent assays. After the addition of various concentrations of FGF4 (0, 2.5, 15, or 50 ng/mL) to the incubation medium, cellular functions were evaluated.

RESULTS

The concentration of FGF4 was significantly higher in the aqueous humor of patients with congenital cataract than in that of patients with age-related cataract. The human SRA01/04 lens epithelial cell line was treated with FGF4 and the cell proliferation increased significantly both dose- and time-dependently. The wound healing assay and Transwell migration assay revealed a significant increase in the migration capacity of the SRA01/04 cell line treated with 15 or 50 ng/mL of FGF4 compared with that of control cells. The intensity of immunofluorescent staining for α-smooth muscle actin increased significantly in the SRA01/04 cell line when treated with FGF4. Cytoskeletal protein (F-actin) staining showed that changes of cell morphology were induced in primary lens epithelial cells by FGF4.

CONCLUSIONS

This study provides a comprehensive profile of growth factors in congenital cataract. FGF4 induced cellular changes, and may have utility as a biomarker to predict the formation of visual axis opacification. [J Pediatr Ophthalmol Strabismus. 2020;57(3):159-168.].

Effect of anterior capsule polish on visual function: A meta-analysis

PURPOSE

To investigate the relationship between anterior capsule polish and visual function.

METHODS

Data were obtained from Pubmed, Embase, Web of Science, WanFang, VIP and CNKI up to the end of May 2018, without any date or language restrictions for trials. The modified Jadad scale and the newcastle-ottawa scale were used to assess the quality of included studies. Uncorrected visual acuity (UCVA) and posterior capsule opacification (PCO) were used as outcome variables. Data on anterior capsule polish were pooled using weighted, random-effect meta-analysis.

RESULTS

One randomized controlled trial and 4 observational cohort studies involving 2533 patients were included in the analyses. There was a statistically significant difference of UCVA (OR 1.92, 95% CI 1.41-2.61) between the polish group and the control group, indicating that anterior capsule polish improved UCVA. Further studies with continuous data also suggested that anterior capsule polish was associated with good UCVA (MD 0.11, 95% CI 0.06-0.16). Posterior capsule opacification rate for 1-year or longer follow-up were extracted for 2561 eyes in 3 studies. Posterior capsule opacification rate was lower in the anterior capsule polish group according to summary odds ratio on PCO rate (OR 0.42 95% CI 0.24-0.73).

CONCLUSIONS

Anterior capsule polish prevents complication of modern cataract surgery and benefits on visual function in short term follow-up period.

Killing two birds with one stone: dual blockade of integrin and FGF signaling through targeting syndecan-4 in postoperative capsular opacification

The most common complication after cataract surgery is postoperative capsular opacification, which includes anterior capsular opacification (ACO) and posterior capsular opacification (PCO). Increased adhesion of lens epithelial cells (LECs) to the intraocular lens material surface promotes ACO formation, whereas proliferation and migration of LECs to the posterior capsule lead to the development of PCO. Cell adhesion is mainly mediated by the binding of integrin to extracellular matrix proteins, while cell proliferation and migration are regulated by fibroblast growth factor (FGF). Syndecan-4 (SDC-4) is a co-receptor for both integrin and FGF signaling pathways. Therefore, SDC-4 may be an ideal therapeutic target for the prevention and treatment of postoperative capsular opacification. However, how SDC-4 contributes to FGF-mediated proliferation, migration, and integrin-mediated adhesion of LECs is unclear. Here, we found that downregulation of SDC-4 inhibited FGF signaling through the blockade of ERK1/2 and PI3K/Akt/mTOR activation, thus suppressing cell proliferation and migration. In addition, downregulation of SDC-4 suppressed integrin-mediated cell adhesion through inhibiting focal adhesion kinase (FAK) phosphorylation. Moreover, SDC-4 knockout mice exhibited normal lens morphology, but had significantly reduced capsular opacification after injury. Finally, SDC-4 expression level was increased in the anterior capsule LECs of age-related cataract patients. Taken together, we for the first time characterized the key regulatory role of SDC-4 in FGF and integrin signaling in human LECs, and provided the basis for future pharmacological interventions of capsular opacification.

Biocompatibility of intraocular lens materials

PURPOSE OF REVIEW

To provide an update on currently available materials used in the manufacture of intraocular lenses, as well as new materials under development, especially with regard to their uveal and capsular biocompatibility.

RECENT FINDINGS

The biocompatibility of intraocular lens materials should be assessed in terms of uveal biocompatibility, related to the inflammatory foreign-body reaction of the eye against the implant, as well as in terms of capsular biocompatibility, determined by the relationship of the intraocular lens with remaining lens epithelial cells within the capsular bag. This situation may result in different entities, e.g. anterior capsule opacification, interlenticular opacification (between piggyback intraocular lenses), posterior capsule opacification and lens epithelial cell ongrowth. Reports on intraocular lens opacification suggest that the potential to calcify should also be taken into consideration when evaluating the long-term biocompatibility of a new material.

SUMMARY

Intraocular lenses are being progressively implanted in much earlier stages of life (refractive lens exchange, pediatric implantation) and are expected to remain in the intraocular environment for many decades. Materials used in intraocular lens manufacture should, therefore, insure long-term uveal and capsular biocompatibility, as well as ultimate transparency after implantation.

Low-intensity ultraviolet A irradiation of the lens capsule to remove lens epithelial cells during cataract surgery

PURPOSE

To assess the effectiveness and safety of low-intensity ultraviolet A (UVA) irradiation in removing lens epithelial cells (LECs) during cataract surgery and compare them with those of mechanical polishing and no treatment.

SETTING

Eyecove Ophthalmology Clinics, Pune, India.

METHODS

This prospective randomized double-masked study consisted of preoperative screening of 36 patients, of which 30 met the inclusion criteria and were recruited. The patients had routine cataract surgery. A bean-shaped capsulorhexis was performed. After the nucleus and cortex were removed, the capsular bag was irradiated from inside with low-intensity UVA in 1 group. A second group had mechanical polishing, and a third group was not treated. A small flap of the anterior capsule was removed in each patient. The flap was stained and mounted in a Fuchs-Rosenthal chamber. For estimation of effectiveness, the area of capsule covered with epithelial cells was estimated by examination under a light microscope. One day postoperatively, an examination was performed to assess the safety of each technique.

RESULTS

The area of the capsule from which the LECs were removed was significantly larger in the UVA-irradiation group than in the mechanical-polishing group (P = .001) and the no-treatment group (P = .001). There was no significant difference between the mechanical-polishing and no-treatment groups (P>.05). The area of the capsule flap that was covered with LECs was significantly less in the UVA-irradiation group than in the mechanical-polishing group (P = .017) and the no-treatment group (P = .001). The mechanical-polishing group and no-treatment group were not significantly different from each other (P>.05). Corneal edema was significantly less in the UVA-irradiation group than in the mechanical-polishing group (P<.001) and no-treatment group (P = .012). No patient in the UVA-irradiation group had postoperative lid edema; 8 patients in each of the other 2 groups had lid edema. The difference was statistically significant (P<.0001). Pupil size was significantly larger in the UVA-irradiation group than in the mechanical-polishing group and no-treatment group; the difference was significant (both P = .0001). There was no significant difference in pupil size in the mechanical-polishing group and no-treatment group. No significant difference was observed between the 3 groups in visual acuity, conjunctival edema, anterior chamber flare, and intraocular pressure.

CONCLUSION

Ultraviolet A irradiation of the capsular bag was effective and safe in removing LECs from the anterior capsule during cataract surgery.

Effect of lens epithelial cell aspiration on postoperative capsulorhexis contraction with the use of the AcrySof intraocular lens

PURPOSE

To determine whether aspiration of lens epithelial cells (LECs) from under the anterior capsule reduces postoperative contraction of the capsulorhexis aperture.

SETTING

Stoke Mandeville Hospital, Aylesbury, Buckinghamshire, United Kingdom.

METHODS

This prospective randomized observer-masked study comprised 100 patients who had routine phacoemulsification by the same surgeon at a district general hospital in the United Kingdom. The postoperative changes in capsulorhexis apertures and anterior capsule opacification (ACO) between Group A (aspiration of LECs) and Group B (control) were compared. Digital retroillumination images of the capsulorhexis aperture were taken 1 week and 3 months postoperatively. The area of capsulorhexis aperture was determined with computer software, and capsule opacification was graded subjectively.

RESULTS

Three months postoperatively, the mean decrease in capsulorhexis aperture was 1.9% in Group A and 5.6% in Group B (P = .02). The ACO at 3 months was grade 2 in 44% of eyes in Group A and in 61% in Group B (P = .13).

CONCLUSION

Aspiration of LECs from the anterior capsule was a safe procedure that reduced capsulorhexis aperture contraction 3 months after cataract surgery.

Lens epithelial cell ongrowth: Comparison of 6 types of hydrophilic intraocular lens models

PURPOSE

To compare the ongrowth of lens epithelial cells (LECs) on the anterior surface of 6 different hydrophilic intraocular lenses (IOLs).

SETTING

Medical University of Vienna, Department of Ophthalmology and Optometry, Vienna, Austria.

METHODS

Six models of hydrophilic IOLs were compared in this prospective study: Visionflex A-100 (Distra Softcryl), Rayner Centerflex 570H (Rayner), Collamer CC4204BF-IOL (Staar), Injectacryl F 3000 (Distra), Hydroview H60M (Bausch & Lomb), and MemoryLens (ORC). Postoperative biomicroscopic examinations were performed 1, 3, 7, 30, 90, 180, and 365 days after surgery. Lens epithelial cells in each quadrant of the anterior capsule-free lens surface were graded. The product with the highest density and the number of quadrants with this density were used to measure LEC ongrowth.

RESULTS

The Hydroview and Visionflex IOLs showed significantly more LECs than the other IOLs starting on day 7 after surgery (P < .028). There was a statistically significant difference in LEC ongrowth on the Memory IOL compared with all other IOLs from day 30 onward (P < .001). The Rayner, Collamer and Injectacryl IOLs had the fewest LECs on the anterior surface compared with all other IOLs from day 7 until the final examination.

CONCLUSIONS

The findings show that LEC ongrowth on the IOL surface is material dependent. The findings suggest that the material of the recently developed hydrophilic IOLs induces less LEC ongrowth than older models.

Removal of lens epithelial cells and the effect on capsulorhexis size

PURPOSE

To assess the long-term effects of lens epithelial cell (LEC) removal on capsulorhexis opening size.

SETTING

Dorset County Hospital, Dorchester, United Kingdom.

METHODS

This prospective randomized control study included 39 eyes of 38 patients. Twenty eyes were selected randomly for removal of LECs from the anterior capsule as part of routine cataract operation comprising phacoemulsification with intraocular lens (IOL) implantation. The other 19 eyes were used as controls in which the LECs were not removed. All surgeries were performed by 1 surgeon (A.T.). All patients had silicone IOL (Allergan SI-40) implantation. The capsulorhexis opening size was determined immediately after surgery and 2 weeks and 6 months after surgery. Data on treatment outcome of the cataract surgery were analyzed statistically.

RESULTS

Six months postoperatively, the size of the capsulorhexis had statistically significant increased in the study group that had LECs removed (mean increase 1.07 +/- 1.70 mm(2); paired Student t test P=.01), whereas the capsulorhexis size had statistically significant decreased in the control group (mean decrease -3.38 +/- 2.37 mm(2); paired Student t test, P<.0001). The difference in changes in the capsulorhexis areas between the 2 groups was also highly statistically significant (independent-sample Student t test, P<.0001).

CONCLUSION

Removal of anterior subcapsular LECs by aspiration helped maintain the size of the capsulorhexis opening and thus can help prevent capsule contraction syndrome.