Liu W, Liu Q, Zhou F, Feng B, Wu WL. Effect of capsule treatment on visual acuity and quality after phacoemulsification lens implantation in myopic patients with cataract. World J Clin Cases 2024; 12(19): 3882-3889 [PMID: 38994309 DOI: 10.12998/wjcc.v12.i19.3882]
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Author contributions: Liu W, Feng B and Wu WL designed this research; Liu W and Liu Q performed this research; Liu W and Zhou F analyzed the data; Liu W, Feng B and Wu WL wrote the manuscript.
Institutional review board statement: This study was approved by the institutional review board of Ganzhou Aier Ophthalmology Hospital.
Informed consent statement: The informed consent has been obtained form each participant.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: The data are available from the corresponding author.
CONSORT 2010 statement: The authors have read the CONSORT 2010 statement, and the manuscript was prepared and revised according to the CONSORT 2010 statement.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Received: April 10, 2024 Revised: May 10, 2024 Accepted: May 20, 2024 Published online: July 6, 2024 Processing time: 79 Days and 22 Hours
Abstract
BACKGROUND
Cataracts pose a significant clinical burden due to their complex pathogenesis. In recent years, an increase in cataracts coexisting with myopia has heightened the incidence of retinopathy and posterior vitreous detachment. Additionally, symptoms of ocular axis elongation, lens nucleus hardening, and vitreous liquefaction have become more prevalent. While conventional extracapsular cataract extraction is commonly employed, it often yields suboptimal visual outcomes. Subsequent advancements in cataract phacoemulsification and lens implantation surgeries have gained widespread acceptance for their ability to improve refraction and significantly improve uncorrected visual acuity.
AIM
To investigate the effect of capsular treatment after phacoemulsification lens implantation in myopic patients with cataract.
METHODS
We selected 110 patients (with 134 eyes) with myopia and cataracts treated. These patients were categorized into two groups: an observation group (57 patients with 70 eyes) and a control group (53 patients with 64 eyes). The control group underwent cataract phacoemulsification and lens implantation, while the observation group received a refined capsular treatment based on the control group’s procedure. We assessed the differences in visual acuity and quality between the two groups before and after surgery.
RESULTS
At six months post-operation, the observation group exhibited significantly improved far vision, intermediate vision, near vision, lower objective scattering index, higher Modulation transfer function cut-off frequency, and overall vision metrics at different contrast levels (100%, 20% and 9%) compared to the control group (P < 0.05). The total score of the National Eye Institute Visual Function Questionnaire in the observation group at 6 months after operation was significantly higher than that in the control group (P < 0.05). No significant difference in the incidence of adverse reactions was observed between the observation group and control group (P > 0.05).
CONCLUSION
Capsular treatment demonstrates efficacy in improving visual acuity and quality after phacoemulsification lens implantation in myopic patients with cataracts, warranting its clinical application.
Core Tip: This study attempted to observe the application value of capsular membrane treatment in myopia with cataract phacoemulsification crystal implantation. The observation indicators included patients' visual acuity and visual quality, and the preliminary study results found that it had certain clinical application value.
Citation: Liu W, Liu Q, Zhou F, Feng B, Wu WL. Effect of capsule treatment on visual acuity and quality after phacoemulsification lens implantation in myopic patients with cataract. World J Clin Cases 2024; 12(19): 3882-3889
Cataracts pose a significant clinical burden due to their complex pathogenesis[1]. In recent years, an increase in cataracts coexisting with myopia has heightened the incidence of retinopathy and posterior vitreous detachment. Additionally, symptoms of ocular axis elongation, lens nucleus hardening, and vitreous liquefaction have become more prevalent[2,3]. While conventional extracapsular cataract extraction is commonly employed, it often yields suboptimal visual outcomes[4,5]. Subsequent advancements in cataract phacoemulsification and lens implantation surgeries have gained widespread acceptance for their ability to improve refraction and significantly improve uncorrected visual acuity[6,7].
However, recent studies have identified postoperative complications, such as changes in intraocular lens (IOL) position, eccentric lens displacement, and posterior capsule clouding, associated with residual lens epithelial cells on the capsule membrane[8,9]. Despite clinical consideration given to removing lens epithelial cells to improve these complications, a critical gap remains in understanding the optical approach for effective capsular membrane treatment. This knowledge gap necessitates further exploration to refine capsular membrane treatment through meticulous anterior and posterior capsular membrane polishing[10,11]. This study aims to perform capsular membrane treatment during conventional phacoemulsification and lens implantation surgery. Our objective is to investigate the effectiveness of this approach in treating patients with myopia and cataracts by observing its effects on visual acuity and quality and potential adverse effects to provide a basis for the clinical selection of the optimal solution for enhancing visual outcomessuch cases.
MATERIALS AND METHODS
General information
We selected 110 patients with 134 eyes diagnosed with myopia and cataracts treated at our hospital from January 2020 to January 2022. The inclusion criteria were: (1) Patients with an eye axis length ≥ 26 mm and diopter ≥ -6.0 D; (2) corneal astigmatism ≤ 1.00 D and Kappa angle < 0.4 mm; (3) cataract nuclear hardness conforming to grades II to IV in Emery’s classification[12]; and (4) Informed consent from both patients and family members. The exclusion criteria were as follows: (1) Traumatic cataract, congenital cataract; (2) previous history of ocular surgery; (3) other ocular diseases such as retinal detachment, macular degeneration, and uveitis; and (4) concurrent serious diseases such as combined malignant tumours, liver and kidney diseases, and other important organ diseases. Patients were grouped by envelope method and divided into an observation group with 57 cases and 70 eyes and a control group with 53 cases and 64 eyes. Both groups' comparative clinical general information is presented in Table 1, indicating comparability. The study was approval by the hospital ethics committee.
Table 1 Comparison of clinical general data between the observation group and control group.
Group
Cases
Sex
Age (yr)
Body mass index (kg/m2)
Axial length of eyeball (mm)
Diopter (D)
Emery grade (number of eyes)
Male
Female
II
III
IV
Observation group
57
32 (56.14)
25 (43.86)
65.59 ± 9.92
22.19 ± 2.04
26.76 ± 1.21
-4.20 ± 0.88
10 (14.29)
34 (48.57)
26 (37.14)
Control group
53
33 (62.26)
20 (37.74)
64.40 ± 9.17
22.04 ± 2.31
26.80 ± 1.09
-4.12 ± 0.90
8 (12.50)
31 (48.44)
25 (39.06)
t/χ2
0.426
0.652
0.362
-0.182
-0.471
0.112
P value
0.514
0.516
0.718
0.856
0.638
0.946
Treatment and follow-up method
Both groups underwent cataract phacoemulsification and lens implantation treatment. The control group underwent routine surgery without capsule treatment, while the observation group underwent refined capsule treatment during the therapy.
In the observation group, a 2.8 mm long clear corneal incision was made at 11:00, and an appropriate amount of viscoelastic was injected into the anterior chamber with promethaine hydrochloride used for surface anesthesia. A lateral incision of 1 mm in length was made at the 3:00 position. After adequate water separation, a continuous circular tear of approximately 5.5 mm diameter was performed using capsular tear forceps. Phacoemulsification was then conducted by placing the ultrasonic emulsification needle in the center of the capsular bag to complete the emulsification of the nuclear mass and aspirate cortex while immobilizing the needle. An IOL was implanted into the capsular bag, and a small amount of viscoelastic material was injected into the bag to bulge the posterior capsular membrane. The posterior capsule was polished using an IF-8208 capsule polisher to remove any remaining lens epithelial cells on the capsule. The IOL forms a symmetrical extension within the capsular bag, straining the posterior capsule and increasing the contact between the IOL optical surface and the posterior capsule, creating a mechanical “barrier” between them. The anterior chamber and capsular bag were filled with viscoelastic materialand the 360°anterior capsular membrane was polished through the main and lateral incisions, respectively. The Tecnis ZMB00 IOL was implanted in the capsular bag, and the residual viscoelastic material was aspirated from the anterior chamber.
Inspection method
The following assessments were conducted 6 months postoperatively: (1) Visual acuity assessment[13]: The naked eye visual acuity was measured at distances 5 m (far), 80 cm (middle), and 40 cm (near) using an international standard visual acuity chart. A lower measured value indicates better visual acuity; and (2) Objective visual quality examination[14]: The modulation transfer function cut-off frequency (MTF cut-off), objective scattering index (OSI), and OQAS value (OV) at three contrast levels (100%, 20%, and 9%), were measured using the OQAS II system.
Postoperative IOP elevation and accidental rupture of the capsular membrane were also observed.
Evaluation tool
The Chinese version of the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) was used to assess the vision-related quality of life of the patients. It encompasses items on general health, general vision, eye pain, near work, and distance work, with a total score of 100, with lower scores indicating poorer vision-related quality of life[15].
Statistical treatment
The data were analyzed using SPSS software version 22.0. Measurement data included age, body mass index, and ocular axis length, were expressed as mean ± SD. The t-test was used to analyze the differences in indicators between groups. Sex and Emery classification, expressed by n (%), were considered as count data, while the chi-square was used to analyze the difference in indicators between groups. Statistically significant was set at P < 0.05 for comparing indicators between groups.
RESULTS
Comparison of visual acuity before and after surgery
Both groups' visual acuity improved six months after surgery compared to before surgery (P < 0.05). Additionally, the far vision, middle vision, and near vision in the observation group at six months after surgery were lower than those in the control group (P < 0.05) (Table 2).
Table 2 Comparison of visual acuity between the two groups before and after operation.
Comparison of objective visual quality between both groups before and after surgery
The objective visual quality at six months postoperatively improved in the observation and control groups compared with the preoperative period (P < 0.05). Specifically, the OSI at six months postoperatively in the observation group was significantly lower than that in the control group (P < 0.05), while the MTF cut-off, 100% OV, 20% OV, and 9% OV were significantly higher than those in the control group (P < 0.05) (Table 3).
Table 3 Comparison of objective visual quality between the two groups before and after operation.
Comparison of the NEI-VFQ-25 scale scores between the two groups before and after surgery
The total score of the NEI-VFQ-25 scale and the scores of each item were higher in the observation group and the control group 6 months after surgery than before surgery (P < 0.05); the total score of NEI-VFQ-25 scale in the observation group at six months after surgery was significantly higher than in the control group (P < 0.05) Additionally, the scores of each item of NEI-VFQ-25 scale in the observation group at six months after surgery were significantly higher than those in the control group (P < 0.05) (Table 4).
Table 4 Comparison of scores of 25-item National Eye Institute Visual Functioning Questionnaire before and after operation between the two groups.
Comparison of complication rates between the two groups
Two cases of postoperative IOP elevation and one case of accidental rupture of the capsule occurred in the observation group. In comparison, four cases of postoperative IOP elevation occurred in the control group. There was no statistical difference in the incidence of complications between the two groups (c2 = 0.010, P = 0.921 > 0.05).
DISCUSSION
Myopia and cataracts interact with each other, as shown by the long myopic eye axis, which leads to cataracts, lens degeneration, and hardening of the lens nucleus, resulting in refractive changes and myopia[16-18]. The symptoms of cataracts comorbid with myopia are more complicated, and the standard approach involves phacoemulsification combined with IOL implantation, which is often used to improve visual quality and reduce dependence on corrective glasses[19,20]. Studies have shown that[21,22] IOL implantation may lead to capsular bag collapse and increase α-smooth muscle actin expression if the lens epithelium remains in the anterior part of the capsule, leading to anterior capsule contraction. Furthermore, fibrosis of the lens epithelium behind the capsule may further affect the visual quality, underscoring the importance of capsule management[23-25].
In this study, patients with myopia accompanied by cataracts were included: the control group received conventional cataract phacoemulsification combined with IOL implantation treatment. In contrast, the observation group received refined capsular treatment based on the control group. At 6 months after surgery, the observation group's improvement in distance, middle, and near vision was more significant than in the control group. This indicates that capsule treatment is beneficial for visual acuity recovery. Continuous circumferential capsular tearing and polishing after phacoemulsification combined with IOL implantation may prevent asymmetric contraction of the capsular bag while removing the lens epithelium when treating the capsular membrane can effectively stabilise the IOL and enhance visual acuity recovery.
The OSI is a quantitative visual quality assessment, with higher values indicating greater intraocular scatter[26,27]. The MTF cut-off essentially denotes the spatial frequency at the maximum resolution of the human eye and is positively correlated with visual quality[28]. OV refers to image contrast at a specific spatial frequency[29]. These metrics allow quantitative evaluation of the visual quality of the patients. The results of this study showed that six months after surgery, the OSI of the observation group was significantly lower than that of the control group. At the same time, the MTF cut-off, 100% OV, 20% OV, and 9% OV were higher than those of the control group. This study suggests that the improvement in visual quality in the observation group was more significant than that in the control group, and treatment with the capsule membrane in the observation group during phacoemulsification and lens implantation significantly improved the visual quality of patients. The patient’s capsular bag is prone to contraction and laxity of the suspensory ligament; these pathological changes are often asymmetrical and can cause IOL displacement. Viscoelastic injection in the capsule membrane prevents retinal detachment and stabilizes the capsular bag, reducing asymmetric contraction and movement and ultimately stabilizing the lens. After capsular membrane treatment, the IOL adhered well to the posterior capsular membrane, which further secured the stability of lens cell migration toward the visual axis region, thus improving visual quality in the observation group protocol[30].
The NEI-VFQ-25 questionnaire used in this study was modified and developed according to the characteristics of the domestic population to reflect changes in the vision-related quality of life in patients with eye disease[31,32]. The results of this study showed that the total score in the observation group was significantly higher than that in the control group six months after surgery, indicating improved vision-related quality of life. Focused capsular membrane management during phacoemulsification combined with lens implantation can improve difficulties and mental stress caused by visual impairment in patients. Fine treatment of the capsular membrane was implemented by fine polishing the anterior and posterior capsular membranes, improving the treatment results. The patients also showed a significant improvement in visual quality after surgery. Vision-related quality of life also improves when the visual quality improves.
Finally, the complication rate did not differ significantly between the groups, suggesting that capsular membrane treatment did not increase the risk of complications. Notably, Placing the ultrasonic emulsification needle at the center of the capsular bag during surgery minimized ultrasound energy usage, enhancing procedural safety.
In this study, vision-related quality of life indicators were also included to provide more comprehensive information in addition to assessing changes in visual acuity and complications. This was done to evaluate the efficacy of capsule treatment-assisted phacoemulsification combined with lens implantation for myopia with cataracts.
While, this study has some limitations, such as the limited sample size and follow-up period. And a larger and more extensive study could be the next step.
CONCLUSION
In conclusion, capsule treatment demonstrates clinical utility by restoring visual acuity and quality of life after myopia with cataract phacoemulsification combined with lens implantation.
Footnotes
Provenance and peer review: Unsolicited article; Externally peer reviewed.
Peer-review model: Single blind
Specialty type: Ophthalmology
Country of origin: China
Peer-review report’s classification
Scientific Quality: Grade C
Novelty: Grade C
Creativity or Innovation: Grade B
Scientific Significance: Grade B
P-Reviewer: Kayapanda M, India S-Editor: Gong ZM L-Editor: A P-Editor: Zheng XM
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