Surgically Induced Astigmatism after Manual Extracapsular Cataract Extraction or after Phacoemulsification Procedure

Results and complications of surgeons-in-training learning bimanual microincision cataract surgery

PURPOSE

To evaluate visual outcomes and complications of bimanual microincision cataract surgery performed by surgeons in training.

SETTING

Institute of Ophthalmology, University of Modena and Reggio Emilia, Modena, Italy.

DESIGN

Prospective case series.

METHODS

The corrected distance visual acuity (CDVA), astigmatism, corneal pachymetry, and endothelial cell count were evaluated before and 7 and 30 days after bimanual MICS performed by surgeons in training. Intraoperative and postoperative complications were also recorded.

RESULTS

Three surgeons in training performed bimanual MICS in 150 eyes of 131 patients. There were 18 intraoperative complications (12.0%) (10 iris traumas [6.6%]; 4 capsule ruptures without vitreous loss [2.7%]; 3 capsule ruptures with vitreous loss [2.0%]; 1 intraocular lens [IOL] implantation in the sulcus due to zonular laxity [0.7%]). There were 5 postoperative complications (3.3%) (2 iris prolapses [1.3%]; 1 IOL loop malposition [0.7%]; 1 narrowing of anterior chamber [0.7%]; 1 capsulorhexis phimosis [0.7%]). Thirty days postoperatively, the mean CDVA improvement was 0.53 ± 0.20 (Snellen decimal) (P < .05), the mean decrease in astigmatism was 0.09 ± 0.54 diopter (P = .29), and the mean increase in corneal pachymetry was 7.42 ± 22.01 μm (P = .12). There was statistically significant endothelial cell loss (mean 496.50 ± 469.66 cells/mm(2)) (P < .05).

CONCLUSIONS

Bimanual MICS performed by surgeons in training was safe and effective. Visual outcomes and complication rates were similar to those reported for coaxial cataract surgery performed by surgeons in training.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Phacoemulsification with posterior chamber intraocular lens versus extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens for age-related cataract

BACKGROUND

Age-related cataract is one of the leading causes of blindness worldwide. Therefore, it is important to establish the most effective surgical technique for cataract surgery.

OBJECTIVES

The aim of this review is to examine the effects of two types of cataract surgery for age-related cataract: phacoemulsification and extracapsular cataract extraction (ECCE).

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2013), EMBASE (January 1980 to May 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to May 2013), Web of Science Conference Proceedings Citation Index - Science (CPCI-S) (January 1970 to May 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 13 May 2013.

SELECTION CRITERIA

We included randomised controlled trials of phacoemulsification compared to ECCE for age-related cataract.

DATA COLLECTION AND ANALYSIS

Two authors independently selected and assessed all studies. We defined two primary outcomes: 'good functional vision' (presenting visual acuity of 6/12 or better) and 'poor visual outcome' (best corrected visual acuity of less than 6/60) at three and 12 months after surgery. We also collected data on intra and postoperative complications, and the cost of the procedures.

MAIN RESULTS

We included 11 trials in this review with a total of 1228 participants, ranging from age 45 to 94. The studies were generally at unclear risk of bias due to poorly reported trial methods. No study reported presenting visual acuity, so we report both uncorrected (UCVA) and best corrected visual acuity (BCVA). Studies varied in visual acuity assessment methods and time frames at which outcomes were reported. Participants in the phacoemulsification group were more likely to achieve UCVA of 6/12 or more at three months (risk ratio (RR) 1.81, 95% confidence interval (CI) 1.36 to 2.41, two studies, 492 participants) and one year (RR 1.99, 95% CI 1.45 to 2.73, one study, 439 participants). People in the phacoemulsification group were also more likely to achieve BCVA of 6/12 or more at three months (RR 1.12, 95% CI 1.03 to 1.22, four studies, 645 participants) and one year (RR 1.06, 95% CI 0.99 to 1.14, one study, 439 participants), but the difference between the two groups was smaller. No trials reported BCVA less than 6/60 but three trials reported BCVA worse than 6/9 and 6/18: there were fewer events of this outcome in the phacoemulsification group than the ECCE group at both the three-month (RR 0.33, 95% CI 0.20 to 0.55, three studies, 604 participants) and 12-month time points (RR 0.62, 95% CI 0.36 to 1.05, one study, 439 participants). Three trials reported posterior capsule rupture: this occurred more commonly in the ECCE group than the phacoemulsification group but small numbers of events mean the true effect is uncertain (Peto odds ratio (OR) 0.56, 95% CI 0.26 to 1.22, three studies, 688 participants). Iris prolapse, cystoid macular oedema and posterior capsular opacification were also higher in the ECCE group than the phacoemulsification group. Phacoemulsification surgical costs were higher than ECCE in two studies. A third study reported similar costs for phacoemulsification and ECCE up to six weeks postoperatively, but following this time point ECCE incurred additional costs due to additional visits, spectacles and laser treatment to achieve a similar outcome.

AUTHORS' CONCLUSIONS

Removing cataract by phacoemulsification may result in a better visual acuity compared to ECCE, with a lower complication rate. The review is currently underpowered to detect differences for rarer outcomes, including poor visual outcome. The lower cost of ECCE may justify its use in a patient population where high-volume surgery is a priority, however, there are a lack of data comparing phacoemulsification and ECCE in lower-income settings.

Phacoemulsification versus extracapsular extraction: governmental costs

PURPOSE

To evaluate the governmental costs of patients undergoing phacoemulsification and extracapsular cataract extraction at a public hospital in a developing country.

METHODS

A prospective study was conduced with 205 patients. The subjects were randomized for cataract surgery using either phacoemulsification or extracapsular cataract extraction techniques.

RESULTS

Of the 205 patients, 101 patients were submitted to phacoemulsificationand 104 patients were submitted to extracapsular cataract extraction. Brazilian Health Care System expenditures for the surgery and the postoperative period were US$ 95.49 more in the phacoemulsification group than in the extracapsular cataract extractiongroup. If we take into account Social Security expenditures, then we estimate that the average difference for the total direct cost for the government for the surgery and the postoperative period for both procedures was US$ 50.91 or approximately half of the initial difference in cost for the phacoemulsification surgery. The total cost of cataract surgery for the government (excluding social security) was estimated at US$ 258.79 for extracapsular cataract extraction and US$ 309.70 for phacoemulsification per patient. Focusing only on working patients, the total cost was US$ 342.21 for phacoemulsification and US$ 587.71 for extracapsular cataract extraction, a difference of US$ 245.50. This difference can be considered monetarily and socially justifiable when the benefits of the surgical technique are evaluated.

CONCLUSION

Under the conditions of this study, we observed that phacoemulsification was an efficient procedure with regard to the impact on public health care system, when all costs are assessed comprehensively, mainly for subjects with regular jobs.

Bimanual microphacoemulsification versus coaxial miniphacoemulsification: Prospective study

PURPOSE

To compare the outcomes of bimanual microphacoemulsification and coaxial miniphacoemulsification and assess the potential advantages of the former over the latter.

SETTING

Institute of Ophthalmology, University of Modena, Modena, Italy.

METHODS

In a controlled prospective clinical trial, 100 eyes of 50 patients with nuclear or corticonuclear cataract of grade 2 to 4 on the Lens Opacities Classification System III had phacoemulsification. Fifty eyes were randomized to have surgery by the bimanual technique and 50, by the coaxial technique. All surgeries were performed by the same surgeon using the same machine (Sovereign WhiteStar, American Medical Optics). In all cases, the incision was made superiorly in clear cornea and a hydrophobic acrylic flexible intraocular lens (Acri. Smart 48 S, Acri.Tec) was implanted. Intraoperative parameters were mean phacoemulsification time, total phacoemulsification percentage, effective phacoemulsification time (EPT), total volume of balanced salt solution (BSS) used, total surgical time, and final size of the corneal incision. Postoperative parameters were visual acuity, astigmatism changes by vector analysis, corneal thickness, endothelial cell count, and presence of flare and cells in the anterior chamber.

RESULTS

The only statistically significant difference between the 2 groups was the total volume of the BSS used (P = .004) and total surgical time (P = .045).

CONCLUSIONS

Both techniques were safe and effective for cataract surgery. With bimanual microphacoemulsification, significantly less BSS was used and the total surgical time was significantly shorter than with the coaxial method.

The effect of incisions for cataract on corneal curvature

PURPOSE

To determine the magnitude and duration of change on the horizontal and vertical meridians of the cornea after five different incisions for cataract.

DESIGN

Retrospective comparative interventional study of five commonly used incisions for cataract surgery: extracapsular cataract extraction (ECCE), 6-mm superior scleral tunnel (6Sup), 3-mm superior scleral tunnel (3Sup), 3-mm temporal scleral tunnel (3Temp), and 3-mm temporal corneal incision (3Cor).

PARTICIPANTS

A total of 662 cases with preoperative regular astigmatism, measured with keratometry.

METHODS

The mean net change on each meridian was computed at 1 day, 1 week, 2 weeks, 1 month, 1.5 months, 2 months, 4 months, 6 months, and 12 months and at succeeding 6-month intervals after surgery. Best-fit parameters were calculated for the observed changes in the horizontal and vertical keratometry values after each incision. To determine when the cornea stabilized, average change on the horizontal and vertical meridians was compared with an estimate of the accuracy of keratometry measurement.

MAIN OUTCOME MEASURES

The pattern of change on the horizontal and vertical meridians and time for the cornea to stabilize after each incision.

RESULTS

The initial and final net changes after a superior incision decrease with length. A sigmoid equation describes the course of the changes on the horizontal and vertical meridians after the superior incisions. The changes after the temporal incisions depend linearly on time after surgery. Considering the uncertainty of keratometry, the corneal meridians stabilized 4.5 months after ECCE, 1.2 months after 6Sup, and 0.3 months after 3Sup. No significant change was detected on the horizontal and vertical meridians after 3Temp and 3Cor.

CONCLUSIONS

The magnitude and the duration of keratometric change on the horizontal and vertical meridians of the cornea depend on the length and location of the incision. Within the limits of measurement error, no significant change in corneal curvature was detected after either small temporal incision.