Capsular Outcomes After Pediatric Cataract Surgery Without Intraocular Lens Implantation: Qualitative Classification and Quantitative Measurement

Reopening the capsular bag by removing the capsular proliferative membrane to enable secondary in-the-bag intraocular lens implantation in pediatric aphakic eyes

PURPOSE

To present a surgical technique for reopening the capsular bag in pediatric aphakia.

SETTING

Zhongshan Ophthalmic Center, Guangzhou, China.

DESIGN

Case series study.

METHODS

Consecutive pediatric patients with bilateral aphakia requiring secondary intraocular lens (IOL) implantation between July 2021 and June 2022 were included. The diameter of the capsular proliferative membranous ring (PMR) and position of IOL implantation were documented. Various parameters of capsular bag opening during primary cataract removal and secondary surgery were also analyzed.

RESULTS

48 eyes were included with a mean follow-up of 8.1 ± 4.4 months. Using the surgical technique developed in this study, the capsular bag was successfully reopened with in-the-bag (ITB) implantation in 43 eyes (89.6%). ITB implantation was accomplished in all eyes with an outer diameter of PMR ≤5.5 mm and in 3 of 8 eyes (37.5%) with an outer diameter of PMR >5.5 mm. A positive correlation was observed between the primary and secondary anterior capsular opening diameters (ACODs) ( r = 0.422, P = .007) and the primary and secondary posterior capsular opening diameters (PCODs) ( r = 0.619, P < .001). The inner diameter of PMR was found to be positively correlated with secondary PCOD ( r = 0.728, P < .001) and the outer diameter with secondary ACOD ( r = 0.669, P < .001).

CONCLUSIONS

This was a safe and effective surgical technique for pediatric secondary IOL implantation with maximum preservation of the peripheral capsule. Aphakic eyes with an outer diameter of PMR ≤5.5 mm are preferred for secondary ITB implantation.

Capsulotomy opening diameter outcomes in aphakic eyes after primary congenital cataract removal and its association

Aim

To observe the change of capsulotomy opening diameter (COD) in aphakic eyes after primary congenital cataract removal and investigate its influencing factors.

Methods

Ocular parameters, including corneal diameter (CD), axial length (AL), anterior and posterior COD (ACOD, PCOD), and age at surgery were recorded at primary congenital cataract removal and secondary intraocular lens implantation. The concentrations of 15 kinds of cytokines in aqueous humor samples collected at the primary surgery were detected. The change (Δ) of COD between two surgeries were described, and its association was analyzed.

Results

Fifty eyes from 33 patients with congenital cataract who underwent primary and secondary surgery were enrolled. The changes in ACOD and PCOD were not statistically significant on the whole. ΔACOD was positively correlated with ΔCD and the concentrations of PDGF-AA, VEGF and TGF-β1. The concentration of FGF-2 and the interval between two surgeries showed negative correlations with ΔACOD and ΔPCOD.

Conclusion

COD in aphakic eyes kept changing after primary surgery. The positive correlation between ΔACOD and ΔCD manifested the enlargement of ACOD was influenced by lateral eye growth. Meanwhile, ΔACOD was also associated with cytokines, indicating postoperative inflammation promoted the ACOD constriction.

Posterior Capsular Outcomes of Pediatric Cataract Surgery With In-The-Bag Intraocular Lens Implantation

AIM

To investigate the change of posterior capsular outcomes of pediatric cataract surgery with primary in-the-bag intraocular lens (IOL) implantation.

METHODS

We conducted a case series of pediatric cataract children who underwent cataract extraction with primary in-the-bag IOL implantation, posterior capsulorhexis or vitrectorhexis, and limited anterior vitrectomy at the Eye Hospital of Wenzhou Medical University between 2016 and 2019. Digital retro-illumination photographs of pediatric eyes were obtained at baseline and 6 months, 12 months, and the last visit postoperatively. Capsular outcomes of the posterior capsular opening area (PCOA) and lens reprolifration area at those time points were compared. Correlations between the PCOA and influential factors, such as age at surgery, axial growth, and follow-up duration, were analyzed. The study was registered at register.clinicaltrials.gov (NCT04803097).

RESULTS

Data of 23 patients (27 eyes) were used in the final analysis. During follow-up, the PCOA enlarged at a rate of 0.29-0.32 mm²/month during the first six months postoperatively and 0.05-0.08 mm²/month over the next 1-2 years. Six months postoperatively, the PCOA enlargement statistically and positively correlated with the follow-up duration and axial growth. The area of lens reprolifration was 0.46 ± 1.00 mm² at six months postoperatively and then remained stable.

CONCLUSION

The PCOA enlarged rapidly within the first six months after the pediatric cataract surgery with primary IOL implantation. Six months postoperatively, the enlargement of PCOA was positively correlated with follow-up duration and axial growth. Posterior capsulorhexis or capsulectomy should be performed with a diameter of 3.0 to 4.0 mm for good visual axis transparency and the protection of in-the-bag IOL.

Lens regeneration in humans: using regenerative potential for tissue repairing

The crystalline lens is an important optic element in human eyes. It is transparent and biconvex, refracting light and accommodating to form a clear retinal image. The lens originates from the embryonic ectoderm. The epithelial cells at the lens equator proliferate, elongate and differentiate into highly aligned lens fiber cells, which are the structural basis for maintaining the transparency of the lens. Cataract refers to the opacity of the lens. Currently, the treatment of cataract is to remove the opaque lens and implant an intraocular lens (IOL). This strategy is inappropriate for children younger than 2 years, because a developing eyeball is prone to have severe complications such as inflammatory proliferation and secondary glaucoma. On the other hand, the absence of the crystalline lens greatly affects visual function rehabilitation. The researchers found that mammalian lenses possess regenerative potential. We identified lens stem cells through linear tracking experiments and designed a minimally invasive lens-content removal surgery (MILS) to remove the opaque lens material while preserving the lens capsule, stem cells and microenvironment. In infants with congenital cataract, functional lens regeneration in situ can be observed after MILS, and the prognosis of visual function is better than that of traditional surgery. Because of insufficient regenerative ability in humans, the morphology and volume of the regenerated lens cannot reach the level of a normal lens. The activation, proliferation and differentiation of lens stem cells and the alignment of lens fibers are regulated by epigenetic factors, growth factors, transcription factors, immune system and other signals and their interactions. The construction of appropriate microenvironment can accelerate lens regeneration and improve its morphology. The therapeutic concept of MILS combined with microenvironment manipulation to activate endogenous stem cells for functional regeneration of organs in situ can be extended to other tissues and organs with strong self-renewal and repair ability.