Purpose
To study the results of phacoemulsification cataract surgery complicated by anterior capsule tear.
Design
Retrospective interventional controlled case series.
Methods
Consecutive series of eyes suffering intraoperative anterior capsule tear and others with uneventful cataract surgery at Moorfields Eye Hospital were investigated. Biometric, intraoperative, and postoperative details were recorded. The exclusion criteria were combined surgical procedures, planned manual extracapsular cataract extraction, and history of previous intraocular surgery or eye trauma. The main outcome measures were intraoperative capsule complication rates, refractive and visual outcomes, and incidence of short-term postoperative complications. Two-sided Fisher exact and paired t tests were used for categorical and continuous data, respectively.
Results
The study and control groups included 239 and 212 eyes, respectively. In the study group, planned phacoemulsification was converted to manual extraction in 5 cases (2%); a concurrent posterior capsule rupture occurred in 58 eyes (24%) with a rate of nuclear lens material drop in the posterior segment of 5% (11 cases). Over 11% of eyes (n = 27) underwent unplanned secondary surgical procedures. Overall, the refractive outcomes were poor in 22.4% of eyes (postoperative refraction ≥1 diopter of target), and were statistically worse ( P < .0001). A significant visual improvement was observed in the majority of the study group eyes (71%); permanent visual loss occurred in 4 eyes (1.7%).
Conclusions
Anterior capsule tear can lead to additional intraoperative complications, with a relatively high incidence of secondary interventions. Overall, permanent visual loss can be observed and worse refractive outcomes are to be expected, particularly if the lens is being implanted out of the bag.
Since Gimbel and Neuhann first described their technique for obtaining a circular and continuous anterior capsulorrhexis, surgeons have appreciated the fundamental value of this surgical step for improving surgical outcomes in cataract surgery. In fact, a continuous circular capsulorrhexis might reduce the incidence of posterior capsule rupture, a complication potentially associated with a slower postoperative visual improvement and increased risk for further surgical interventions. As is well known, a permanent visual acuity deterioration is also possible following posterior capsule rupture. Additionally, a continuous capsulorrhexis limits the occurrence of significant postoperative intraocular lens (IOL) tilt and decentration that could lead to worse visual and refractive outcomes.
As a consequence, anterior capsule tear can potentially affect the quality of cataract surgery even more than posterior capsule rupture may do: it can cause a posterior capsule rupture, with longer rehabilitation, and it can also prevent an ideal lens fixation, with major postoperative refractive errors and patient dissatisfaction. Moreover, early secondary surgical intervention is required in cases of poor postoperative IOL fixation resulting from the inadequate capsule support attributable to the association of anterior and posterior capsule tears. In light of these considerations, it is somehow surprising to see how little evidence is available on anterior capsule tear.
Our study was planned with a view to observing the frequency of associated intraoperative complications and rate of secondary interventions, and to verifying whether a certain IOL type and fixation could be preferable when anterior capsule tear occurs.
Methods
Institutional review board approval (at Moorfields Eye Hospital in London, United Kingdom) was obtained for this retrospective study for the collection of preoperative, intraoperative, and postoperative data, and precautions were taken to protect the identity of the study patients. All research and data collection adhered to the tenets of the Declaration of Helsinki.
Electronic surgical notes of cataract surgery procedures performed at Moorfields Eye Hospital during the years 2012–2013 were examined to identify 250 consecutive cases complicated by anterior capsule tear for this retrospective consecutive interventional controlled case series. The adopted exclusion criteria were combined surgical procedures, planned manual extracapsular cataract extraction (ECCE), and previous intraocular surgery or eye trauma. The same exclusion criteria were also adopted in a previous internal clinical audit study, which investigated the surgical, refractive, and visual outcomes in routine cataract surgery performed at only 1 of the surgical sites of our institution in the time frame June 2012 through August 2012 (unpublished data; data presented at the internal clinical governance meeting in November 2012). The series consisted of 212 consecutive uncomplicated phacoemulsification cataract surgery procedures, and appeared to offer the ideal control group for this series: the same surgical instrumentation, wound size, lens type, and internal recommendations with regard to IOL power selection were used; in addition, no intraoperative complications had occurred in that series. Biometric, intraoperative, and postoperative details were available for eyes in both series. For the eyes in the study group, timing of the capsulorrhexis tear was noted whenever information was available in surgical records.
The Infinity phacoemulsification platform (Alcon Laboratories, Fort Worth, Texas, USA) was employed for all surgical procedures in both series, with a main corneal incision of 2.75 mm in width, and with implantation of Alcon IOLs (the single-piece Acrysof SN60WF and the 3-piece Acrysof MA60AC for posterior chamber fixation, and the angle-supported Kelman multiflex MTA-series IOLs for anterior chamber fixation; Alcon Laboratories). For the determination of the IOL power our institutional guidelines recommended use of the Hoffer Q IOL power prediction formula for eyes with axial length shorter than 22.0 mm and the SRK-T lens formula for all other axial lengths; if a sulcus fixation was chosen, the IOL power was reduced by 0.5 or 1.0 diopter for IOL powers lower or greater than 18 diopters, respectively. We confirmed that the described institutional recommendations had been followed in all cases. In this series, there were no eyes that had previously undergone corneal refractive surgery.
Standard preoperative biometry was performed by trained technicians with the IOL Master (versions 5.4 and 500) (Carl Zeiss Meditec, Dublin, California, USA). If a signal-to-noise ratio below 2.1 was obtained with optical biometry, contact A-scan ultrasound biometry was performed with the Accutome A-scan Plus (Accutome Inc, Malvern, Pennsylvania, USA). Cases with missing information regarding the postoperative refraction and those with a refraction obtained within 4 weeks of surgery were excluded from the refractive outcome analysis. Snellen visual acuity values were converted to logarithm of the minimal angle of resolution (logMAR) value equivalents to enable statistical analysis. Visual acuity of perception of light, hand motion, and counting fingers were set at 2.5, 2.3, and 1.85 logMAR, respectively. Visual and refractive outcomes observed in this study were compared with results observed in a consecutive series of 212 uncomplicated consecutive cases operated at the same institution, as described above.
Statistical Analysis
Continuous variables were described with the mean, standard deviation, and range of values. The Fisher exact tests were used for categorical data; paired t tests were used for continuous data. A P value of less than .05 was considered statistically significant; all tests were 2-sided and based on complete case analysis. All analyses were performed using SPSS software (version 20.0; SPSS Inc, Chicago, Illinois, USA).
Results
The study and control groups were similar in terms of axial length and anterior chamber depth ( P = .457 and P = .381, respectively), with mean axial lengths of 23.62 ± 1.68 mm and 23.73 ± 1.43 mm and mean anterior chamber depths of 3.08 ± 0.54 mm and 3.04 ± 0.41 mm.
After applying the selecting criteria, 239 eyes were included in the study. A concurrent posterior capsule rupture, as a result of a tear extending to the posterior capsule, occurred in 58 eyes (24%), with vitreous loss in 38 (16%), and with a rate of any nuclear lens material drop in the posterior segment of 5% (11 eyes) ( Table 1 ).
| Consultant | Fellow | Trainee | Total, n (%) | |
|---|---|---|---|---|
| Posterior capsule rupture | 11 | 33 | 14 | 58 (24%) |
| Vitreous loss | 9 | 21 | 8 | 38 (16%) |
| Nuclear lens material drop | 3 | 4 | 4 | 11 (5%) |
| Choroidal hemorrhage | 1 | 0 | 0 | 1 (0.4%) |
| Iris trauma | 4 | 14 | 4 | 22 (9%) |
| Distribution of cases among different surgical grades | 59 | 125 | 55 | 239 |
In 5 eyes (2%) the operating surgeon converted the planned phacoemulsification cataract surgery procedure to manual ECCE and none of these cases were complicated by nuclear fragment drop. Procedures conducted by lower-surgical-grade surgeons were not at increased risk of associated posterior capsule rupture ( P = .295) in this series. In 84 surgical records, information regarding the timing of the tear was reported, with 45 primary anterior capsule tears (54%). In relation to the timing of tear development, anterior capsule tear can be defined as primary or secondary; the former is intended to be defined as a tear that occurs early during the procedure, before phacoemulsification is commenced. The rates of posterior capsule rupture and vitreous loss did not differ in relation to the timing of the tear ( P = .416 and P = .327, respectively); instead, the differences reached the level of significance in relation to the IOL fixation type: endocapsular IOL fixation was obtained more frequently in cases of secondary tear (64.1% vs 33.3%; P = .008) and sulcus fixation was more often used in cases of primary anterior capsule tear (60.0% vs 30.8%; P = .009).
Critical patient safety incidents were observed in 27 cases requiring additional unplanned surgery (11%). In 10 patients vitreoretinal surgery for removal of lens material dislocated in the vitreous cavity was performed, with the fragment being larger than a lens quadrant in 8 of 10 cases. In the other 17 eyes further surgery was required to correct primary aphakia (11), for IOL dislocation repositioning or exchange (5), and in 1 instance of early rhegmatogenous macula-off retinal detachment. Details of postoperative complications are shown in Table 2 . Short-term complications such as cystoid macular edema, transient ocular hypertension, and prolonged anterior uveitis were overrepresented and resolved in the vast majority within 8 weeks from surgery; long-lasting complications included chronic cystoid macular edema (2), corneal decompensation (1), and chronic anterior uveitis (4). In the control series, a single case of severe postoperative complication (early retinal detachment in a highly myopic patient) occurred and required unplanned surgical readmission; in addition, there were 4 cases of prolonged uveitis and 2 cases of cystoid macular edema, which all resolved with medical treatment alone within 2 months after surgery.
| Number of Eyes (%) (N = 239) | |
|---|---|
| Severe postoperative complications | |
| Acute retinal detachment (within 1 month) | 1 (0.4%) |
| Chronic endothelial disease (requiring surgery within 3 months) | 1 (0.4%) |
| Cystoid macular edema | 8 (3.3%) |
| Chronic cystoid macular edema (reducing vision <logMAR 0.30) | 2 (0.8%) |
| Endophthalmitis | 0 |
| Other postoperative complications | |
| Prolonged anterior uveitis (requiring treatment for >6 weeks) | 25 (10.4%) |
| Early posterior capsule opacity (disturbing vision within 2 months) | 0 |
| Ocular hypertension | 17 (7.1%) |
| Critical patient safety incidents | |
| Unplanned surgical readmission | 27 (11.3%) |
| Expulsive hemorrhage during surgery | 0 |
| Pseudophakic endophthalmitis | 0 |
As expected, there was a diversity of intraocular lens fixation types, with implants placed in the capsular bag in only half of the cases. Of the 121 eyes with bag fixation, 38 were implanted with the Acrysof MA60AC (multi-piece IOL); none of these eyes presented with IOL dislocation or decentration in the early postoperative phases, which instead occurred with 2 single-piece IOLs implanted in the capsular bag and 3 multi-piece IOLs placed in the ciliary sulcus. All 5 of those patients required further surgery for either IOL repositioning or exchange. Primary aphakia occurred in 11 eyes, whereas 4 eyes were implanted with an anterior chamber angle-supported IOL at the time of the primary procedure. At final follow-up 1 eye was still aphakic; in the remaining cases, the IOL was placed in the bag (122 eyes), in the ciliary sulcus (108 eyes), and in the anterior chamber (8 eyes).
The refractive analysis was based on 187 eyes. Generally, the outcomes were slightly more myopic than intended, with a mean refractive error (MNE) of −0.24 ± 0.86 diopter (D) (range −2.92 D ∼ +2.54 D), and the refractive accuracy modest, with a mean absolute error (MAE) of 0.68 ± 0.57 D (range 0.00–1.75 D, median = 0.60 D).These results were compared to the refractive outcomes obtained by eyes in the control group implanted with the same 1-piece IOL in the capsular bag (the MNE and MAE were −0.09 ± 0.48 D and 0.39 ± 0.30 D, respectively). The difference in refractive outcomes between cases complicated by anterior capsule tears and routine uneventful cases in the control series was statistically significant ( P = .030 and P < .0001 for MNE and MAE, respectively). Overall, in the study group, 146 eyes (78.1%) were within 1.00 D of target, while only 79 eyes (42.2%) were within 0.50 D of intended postoperative refraction; these results were significantly worse than the outcomes observed in the control group of eyes with uneventful cataract surgery ( P < .0001). There were 9 eyes with a postoperative refraction of at least 2.00 D off the target (4%). Within the study group, patients implanted with a ciliary sulcus–fixated IOL had worse refractive outcomes than those receiving an endocapsular IOL in terms of number of eyes achieving a final refraction within 0.5 D of target ( P = .007) ( Table 3 ).
| ≤0.5 D of Target | ≤1.0 D of Target | ≤2.0 D of Target | >2.0 D of Target | Total | |
|---|---|---|---|---|---|
| Bag a | 51 (52.0%) | 79 (80.6%) | 93 (94.9%) | 5 (5.1%) | 98 |
| -1-piece IOL | 40 (55.6%) | 60 (83.3%) | 68 (94.4%) | 4 (5.6%) | 72 |
| -3-piece IOL | 11 (42.3%) | 19 (73.1%) | 25 (96.2%) | 1 (3.8%) | 26 |
| Sulcus a | 27 (31.8%) | 63 (74.1%) | 81 (95.3%) | 4 (4.7%) | 85 |
| Anterior chamber a | 3 (75%) | 4 (100%) | 4 (100%) | None | 4 |
| Uncomplicated controls (bag) | 150 (70.8%) | 202 (95.3%) | 212 (100%) | None | 212 |
| P values b | .183 | .235 | >.999 | ||
| P values c | <.001 | .374 | >.999 | ||
| P values d | .043 | <.0001 | .003 |
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