To compare the progression of posterior capsule opacification (PCO) in patients who required Nd:YAG laser capsulotomy following either combined cataract surgery with pars plana vitrectomy (PPV; C-CV), sequential cataract surgery after PPV (S-CV), or cataract surgery alone (CA). The medical records of 321 patients (408 eyes) who underwent Nd:YAG capsulotomy were retrospectively evaluated. The CA group had a significantly longer time interval from cataract surgery to capsulotomy than that of both the CV group
Cataract formation and progression are common postoperative complications after pars plana vitrectomy (PPV) for a variety of vitreoretinal diseases, including epiretinal membrane and macular hole in phakic patients [
Posterior capsule opacification (PCO) is the most common complication after cataract surgery [
Between January 2000 and December 2012, the medical records of 321 patients (408 eyes) who underwent Nd:YAG laser capsulotomies at the Department of Ophthalmology, Dongsan Medical Center, Keimyung University, Daegu, Korea, were retrospectively evaluated. Patients were divided into two primary groups to investigate whether vitreous removal could influence the progression of PCO; there were 212 eyes from 150 patients in the CA group and 196 eyes from 171 patients in the cataract surgery either with or after PPV group (CV group). 62 patients of CA and 25 patients of CV were enrolled in both eyes. For evaluating capable correlation of outcomes on eyes from same patients, we adopted the point biserial correlation coefficients method. The coefficient of correlation was very low, so we included both eyes of the same patients in this study (data not shown). The CV group was subdivided into two secondary groups: 80 eyes from 71 patients in the combined cataract surgery with PPV group (C-CV group) and 116 eyes from 100 patients in the sequential cataract surgery after PPV group (S-CV group). Patients with a history of uveitis, primary aphakia after cataract extraction, glaucoma filtration surgery, repeated vitrectomy after cataract surgery, intraoperative posterior capsule rupture, combined extracapsular cataract extraction with PPV, and extracapsular fixation of the intraocular (IOL) were excluded. Furthermore, cases who were lost to follow-up for more than 1 year were also excluded to avoid overestimation of the interval to capsulotomy.
Data collection included age at cataract surgery, gender, history of diabetes mellitus (DM), and laterality of surgery. The patient demographics are shown in Table
Patient demographics.
Parameter | Group |
|
|||
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CA | CV | ||||
C-CV | S-CV | ||||
Eyes, |
212 (150) | 196 (171) | |||
80 (71) | 116 (100) | ||||
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|||||
Gender (M/F) | 51/99 | 71/100 | 0.179* | ||
35/36 | 36/64 | 0.093* | |||
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|||||
Age (y) | 65.1 ± 10.5 | 57.1 ± 9.0 |
| ||
57.2 ± 9.6 | 57.0 ± 8.5 |
|
|||
|
|||||
Laterality (OD/OS) | 101/111 | 101/95 | 0.488* | ||
41/39 | 60/56 | 0.747* | |||
|
|||||
DM/non-DM | 43 : 169 | 113 : 83 |
| ||
54 : 62 | 59 : 21 |
|
Note. CA: cataract surgery alone; CV: cataract surgery with or after pars plana vitrectomy (PPV); C-CV: combined cataract surgery with PPV; S-CV: sequential cataract surgery after PPV; DM: diabetes mellitus.
*Fisher’s exact test.
**Independent
†One-way ANOVA test.
All surgeries were performed by one experienced surgeons (KKS) using retrobulbar anesthesia. From 2000 to 2010, conventional 20-gauge, 3-port PPVs were used (Premiere DP 3672 200, Storz, USA, and Millennium Phaco Vitrectomy A/P CX3173, Bausch Lomb, USA) and after October 2011, 23-gauge, 3-port PPVs were used (Millennium Phaco Vitrectomy A/P CX3173). Cataract surgeries were performed with Ten Thousand 10,000 Phacoemulsifier/Aspirator (Alcon Laboratories, USA) from 2000 to 2005 and Millennium Phaco Vitrectomy A/P CX3173 (Bausch Lomb, USA) from 2005 to 2013. Combined cataract and PPV surgeries were performed with continuous curvilinear capsulotomy followed by phacoemulsification and an irrigation/aspiration procedure through the scleral tunnel incision. The PPV was performed without implantation of an IOL. After the PPV, the IOL was implanted in the capsular bag. Routinely, cataract surgeries were performed under retrobulbar anesthesia using a standard clear corneal temporal incision. In a small proportion of cataract surgeries, a scleral tunnel incision method was used. After incision, a continuous curvilinear capsulorhexis was performed, followed by hydrodissection and hydrodelineation. The lens nucleus was removed by phacoemulsification, and the cortical fibers were irrigated and aspirated. The IOL was implanted in the capsular bag and stromal hydration was used for sealing the incision.
The mean age and incidence of diabetes were significantly different between the CA and CV groups (Table
Of 321 patients, there were 122 men and 199 women. The mean age at cataract surgery was 61.2 ± 0.5 years (range: 31 to 98 years). The mean age of the CA, CV, S-CV, and C-CV groups was 65.1 ± 10.5 years (range: 31 to 98 years), 57.1 ± 9.0 years (range: 38 to 81 years), 57.2 ± 9.6 years (range: 38 to 81 years), and 57.0 ± 8.5 years (range: 40 to 78 years), respectively. The mean age at cataract surgery of the CV group was significantly younger than that of the CA group (
The mean time interval from cataract surgery to Nd:YAG capsulotomy was significantly longer in the CA group than in the CV group (36.3 ± 26.4 versus 29.1 ± 23.1 months;
Age-matched comparison of the mean time interval from cataract surgery to Nd:YAG capsulotomy.
Parameter | Group |
|
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---|---|---|---|---|
CA | CV | |||
Mean time interval (M) | 36.3 ± 26.4 | 29.1 ± 23.1 |
| |
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CA | C-CV | S-CV | ||
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Mean time interval (M) | 36.3 ± 26.4 | 29.5 ± 24.4 | 28.8 ± 22.2 |
|
Time interval differences from cataract surgery to Nd:YAG capsulotomy within subgroups.
Group |
|
||
---|---|---|---|
Matching of subgroup | CA | C-CV |
|
CA | S-CV |
| |
C-CV | S-CV | 0.321* |
Comparisons of mean time interval from cataract surgery to Nd:YAG capsulotomy in each group (gray bars). The CV group had a shorter time interval than the CA group ((a),
Considering the IOL materials of silicone, hydrophobic acrylic, hydrophilic acrylic, and polymethyl methacrylate (PMMA), there were no differences in Nd:YAG capsulotomy free survival times between material types for the CV group (
Comparison of the mean time interval within the IOL subgroup in cataract surgery with or after vitrectomy and cataract surgery alone.
Subgroup |
|
||||
---|---|---|---|---|---|
Silicone | Hydrophobic acrylic | Hydrophilic acrylic | PMMA | ||
Mean time interval (M) | |||||
CV | 30.7 ± 29.3 | 29.1 ± 21.6 | 25.8 ± 19.9 | 27.1 ± 20.7 | 0.838* |
CA | 36.4 ± 25.3 | 35.5 ± 22.1 | 22.6 ± 8.7 | 32.8 ± 15.9 | 0.066* |
|
0.084** |
|
0.909** | 0.378** |
Note. IOL: intraocular lens; PMMA: polymethyl methacrylate.
*Kruskal-Wallis test.
**Mann-Whitney
†Independent
Comparisons of mean time intervals from cataract surgery to Nd:YAG capsulotomy within IOL subgroups. (a) Means comparison of IOL subgroup in the CV group, and (b) means the comparison of the CA group. Within the CV and CA groups, the IOL subgroup showed no difference in the mean time interval to Nd:YAG capsulotomy (
There were no differences in Nd:YAG capsulotomy free survival times between DM and non-DM patients in either the CA group or the C-CV and S-CV subgroups. Nd:YAG capsulotomy free survival time was not correlated with diabetes history (Table
Comparisons of the mean time interval from cataract surgery to Nd:YAG capsulotomy within the PPV subgroup.
Parameter | Subgroup | ||
---|---|---|---|
CA | C-CV | S-CV | |
Mean time interval (M) | |||
DM | 29.7 ± 22.7 | 32.0 ± 22.8 | 27.6 ± 22.6 |
non-DM | 28.2 ± 23.8 | 26.0 ± 21.6 | 34.7 ± 29.0 |
|
0.654* | 0.152* | 0.323* |
Age-matched partial correlation between the time interval between the PPV and cataract surgeries and the time interval between the cataract surgery and capsulotomy (
The survival curves for each group are shown in Figure
Cox proportional hazards model. Surgical option was identified as a risk factor that influenced the time interval from cataract surgery to capsulotomy. The CV group had a higher risk of a shorter Nd:YAG capsulotomy free survival time than the CA group ((c), hazard ratio (HR) = 1.337; 95% confidence interval (CI) 1.100–1.625;
Several previous studies have investigated factors associated with PCO. From biochemical investigations, various growth factors, extracellular matrices, integrins, and matrix metalloproteinases are related to lens epithelial cell (LEC) proliferation, migration, and transdifferentiation. Postoperative inflammation in the anterior chamber due to surgical trauma, the IOL design, and surgical technique contribute to PCO formation with progression in cataract surgery [
We retrospectively evaluated Nd:YAG capsulotomy free survival times in patients over an extended period, whereas previous studies only focused on the PCO value and rate of laser capsulotomy after sequential or combined surgery. However, the postoperative PCO free duration is also important for patients and ophthalmologists who need to plan post-PPV PCO and vitreoretinal pathology treatments, such as laser photocoagulation or intravitreal injections. The long-term analysis of PCO data should enable an understanding of factors that relate to its progression after cataract surgery with or after PPV.
Toda et al. [
Theoretically, loss of compression of the vitreous body after PPV may cause early PCO formation in sequential and combined surgeries. Nishi et al. [
It is also possible that there is a change of vitreous circulation after vitrectomy. In the nonvitrectomized state, vitreous circulation of oxygen is limited by the vitreous body, which maintains a relatively low oxygenation state around the lens. Elevated oxygen tension after vitrectomy induces a relatively higher concentration of oxygen distribution near the lens [
Our study was retrospective in nature, and there were numerous improvements in surgical materials and techniques over the 14-year review period, leading to potential differences in outcomes between the early and late study periods. Furthermore, in present study, there were a thousand or more cases with past history of laser capsulotomy; we decided to include selective cases that could identify at least one-year follow-up observation in medical records. However, with these exclusions, selection bias could occur because the patients who were attended to our Ophthalmology Department would have specific problems like diabetes, concomitant vitreoretinal disease, and other medical disorders. Particularly, patients with vitreoretinal disease would have chronicity of vision problems and would be enthusiastic to regular follow-up observations. Actually, the majority of exclusion was lost to follow-up; their distributions were higher in simple cataract surgery patients. However, our study provides some comprehensive indicators of the pathophysiology of PCO after cataract surgery with or after PPV. It should also be noted that the ages and proportion of patients with DM were different in each group. As age and diabetes may be related to the rate of PCO after phacovitrectomy or cataract surgery only [
We found that the progressions of PCO are more rapid in patients who underwent combined or sequential cataract surgery and vitrectomy than in patients undergoing CA. For cataract surgery with or after vitrectomy, the formation of postoperative PCO must be considered and appropriate patient counseling and follow-up management should be provided.
The authors declare that there is no conflict of interests regarding the publication of this paper.