VISION Posterior Capsule Opacification (PCO) Cases at Lamongan Eye Clinic: Two Years of Retrospective Data

Introduction: Posterior capsular opacity (PCO) is the most common complication of cataract surgery. PCO is caused by the lens epithelial cells (LEC), which then proliferate in the capsular bag after surgery. Several complications can occur, such as increased intraocular pressure (IOP), cystoid macular edema (CME), retinal hemorrhage, retinal detachment, and implanted lens (IOL) damage. Capsule Nd:YAG laser is currently the standard procedure for treating PCO, with a success rate of 95%. Purpose: This study aimed to provide an overview of PCO incidence and the success rate of PCO handling in the eye clinic. Methods: This study was a retrospective observational study. Data was taken from medical records of patients diagnosed with PCO who came to the Lamongan Eye Clinic for two years (May 2018 to April 2020). Data regarding the profile of the subject was analyzed descriptively. The data distribution was tested using the Kolmogorov-Smirnov test. Results: From May 2018 to April 2020, 134 patients with PCO came to the Lamongan Eye Clinic. Mean pre-laser best-corrected visual acuity (BCVA) was 0.76 ± 0.44 (logMAR), post-laser was 0.40 ± 0.40 (logMAR). There was a significant difference in the mean refraction correction of the PCO patients before and after Nd:YAG laser capsulotomy, whereas the mean BCVA after undergoing YAG laser was higher than before. Mean pre-laser IOP was 15.00 ± 3.55 mmHg and post-laser was 14.20 ± 3.27 mmHg. The mean post-laser IOP was lower than the pre-laser IOP. The Nd:YAG laser capsulotomy significantly affected IOP. Conclusions: There is a statistically significant improvement in BCVA before and after capsulotomy. Capsulotomy had a significant effect on improving BCVA up to 7%; however, had no effect on IOP.


Introduction
Posterior capsular opacity (PCO) is the most common complication of cataract surgery, occurring in patients after phacoemulsification cataract surgery with intraocular lens (IOL) implantation. PCO is a secondary cataract or after cataract caused by the proliferation of lens epithelial cells (LEC) within the capsular bag after surgery, which then migrates to transform myofibroblasts and cause capsular opacification. Sinskey and Cain first reported a PCO incidence of 43% at 26 months of evaluation. [1] Schaumberg et al. [2] reported PCO incidence of 11.8% at one year, 20.7% after two years, and 28.5% after three years postoperatively.
PCO development is a dynamic process involving three basic phenomena: proliferation, migration, and differentiation of residual LEC. [3] Furthermore, PCO is classified into three types based on morphology and cell origin: fibrotic type and Elschnig pearls type, and the third type is Soemmering's ring type. [3] PCO can be managed by capsulotomy, and it is a non-invasive eye surgery done by making an incision in the clear glass-like capsule that wraps around the lens. A capsulotomy is performed using a Nd:YAG laser to open the posterior capsule. The success rate of the Nd:YAG laser capsulotomy procedure is up to 95%. [4] Nevertheless, complications such as increased intraocular pressure (IOP), cystoid macular edema (CME), retinal hemorrhage, retinal detachment, and implanted lens damage can occur. [5] https://e-journal.unair.ac.id/VSEHJ

Results
From May 2018 to April 2020, 134 posterior capsule opacification patients came to the Lamongan Eye Clinic. Table 1 showed that 46.3% of the patients were between 55-65 years old (prasenium phase), and 56.0% were male (Table 2). Table 3 showed the location of the eye surgery; 52.2% had been performed at Lamongan Eye Clinic. Table   4 showed patient's previous eye surgery history; 42.5% had eye surgery in the past year.         of up to 95%. [6] In this study, PCO was more prevalent in men (56.0%) than women (44.0%). Research by Raj et al. [3] and Wren et al. [7] suggested no correlation between PCO and gender.
Ayuningtyas et al. [8] also stated the same thing, while the study by Hashemi et al. [9] found that the incidence was higher in women.
In this study, most patients were in the age range between 55-65 years (46.3%), with a mean age of 63.55 ± 8.72 years. Previous research [4], [10] found that most patients were in the age range of 41 years to 80 years, and Ayuningtyas et al. [8] showed a median age of 65 years with a range of 42 years to 87 years.
In various studies [11], [12], [13], [14], [15], [16] , the period between patients who underwent cataract surgery and PCO formation has been reported to occur from five months to three years. In this study, PCO diagnosis was established after a median of 12 months, ranging from 8.2 months to 26.3 months after cataract extraction. Ayuningtyas et al. [8] found that the duration of the PCO diagnosis was established since surgery with a median of 21 months with a range from one month to 34 months, while Kwon et al. [17] found the duration of the PCO diagnosis was established in 16 months after surgery with a range of 6 to 18 months. It can be concluded that the results obtained in this study were following previous research.
The most common symptom in patients with PCO is blurred vision due to blockage of the visual axis caused by the migration and proliferation of lens epithelial cells from the equator to the visual axis, which causes reduced visual acuity several months years after cataract surgery. [8] It was also found in this study that the best visual acuity after refraction correction on arrival or at the time of PCO diagnosis was obtained with a median of 0.5 logMAR

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Vision Science and Eye Health Journal Suryani, Unari with a range of 0.00 logMAR to 2.80 logMAR. Similar findings were also found by Ayuningtyas et al. [8] , with the BCVA logMAR at the time of diagnosis being 0.50 ± 0.26.
BCVA pre and post-laser showed a significant increase.
The BCVA average before capsulotomy with Nd:YAG laser was 0.2673 ± 0.242; after capsulotomy with Nd:YAG laser, 147 patients had a BCVA average of 13.3078 ± 5.51.
The test results showed a significant difference (p < 0.05).
It followed a previous study by Ayuningtyas et al. [8] with an increased visual acuity after laser treatment with a visual acuity range of 0.7 to 1.00. Kumar et al. [18] also obtained similar results with increased visual acuity in 91.42% of cases. Until now, the most effective action for PCO management was capsulotomy with Nd:YAG laser.
The success rate was 95%, whereas visual clearance of the axis was performed by creating an opening in the central part of the opaque posterior lens capsule.
This study obtained a significant correlation (r = 0.264, p = 0.000) between increased BCVA and Nd:YAG laser capsulotomies in patients diagnosed with PCO. The regression test results also showed a significant effect between capsulotomy Nd:YAG laser with increased BCVA (p = 0.000 and R2 = 0.070 = 7%). In the following research by Bhargava et al. [19] , one of the things that played a role in the success of therapy with Nd:YAG lasers was the energy level used, in which each type of PCO required a different energy level. Posterior capsule opacification, which tends to be thicker, requires higher energy to clean the visual axis and improve visual acuity. [3] Capsulotomy with Nd:YAG laser was a fast, effective, and relatively safe procedure, however, it cannot be denied that it can still cause various complications, one of which was increased IOP. [5]  Similarly, Ramon et al. [20] reported that increased IOP al. [16] study an increase in IOP only occurred in 10% of cases. Recording patient data should be done with a better recording system for patients who come to Lamongan, Suryani, Unari Vision Science and Eye Health Journal Eye Clinic especially in the cataract and refractive surgery division, so that collected data is complete and can be used for further research.