Risk Factors for Intraoperative and Early Postoperative Complications in Extracapsular Cataract Surgery

A Computational Framework for Intraoperative Pupil Analysis in Cataract Surgery

Purpose

Pupillary instability is a known risk factor for complications in cataract surgery. This study aims to develop and validate an innovative and reliable computational framework for the automated assessment of pupil morphologic changes during the various phases of cataract surgery.

Design

Retrospective surgical video analysis.

Subjects

Two hundred forty complete surgical video recordings, among which 190 surgeries were conducted without the use of pupil expansion devices (PEDs) and 50 were performed with the use of a PED.

Methods

The proposed framework consists of 3 stages: feature extraction, deep learning (DL)-based anatomy recognition, and obstruction (OB) detection/compensation. In the first stage, surgical video frames undergo noise reduction using a tensor-based wavelet feature extraction method. In the second stage, DL-based segmentation models are trained and employed to segment the pupil, limbus, and palpebral fissure. In the third stage, obstructed visualization of the pupil is detected and compensated for using a DL-based algorithm. A dataset of 5700 intraoperative video frames across 190 cataract surgeries in the BigCat database was collected for validating algorithm performance.

Main Outcome Measures

The pupil analysis framework was assessed on the basis of segmentation performance for both obstructed and unobstructed pupils. Classification performance of models utilizing the segmented pupil time series to predict surgeon use of a PED was also assessed.

Results

An architecture based on the Feature Pyramid Network model with Visual Geometry Group 16 backbone integrated with the adaptive wavelet tensor feature extraction feature extraction method demonstrated the highest performance in anatomy segmentation, with Dice coefficient of 96.52%. Incorporation of an OB compensation algorithm improved performance further (Dice 96.82%). Downstream analysis of framework output enabled the development of a Support Vector Machine-based classifier that could predict surgeon usage of a PED prior to its placement with 96.67% accuracy and area under the curve of 99.44%.

Conclusions

The experimental results demonstrate that the proposed framework (1) provides high accuracy in pupil analysis compared with human-annotated ground truth, (2) substantially outperforms isolated use of a DL segmentation model, and (3) can enable downstream analytics with clinically valuable predictive capacity.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Adaptive Tensor-Based Feature Extraction for Pupil Segmentation in Cataract Surgery

Cataract surgery remains the only definitive treatment for visually significant cataracts, which are a major cause of preventable blindness worldwide. Successful performance of cataract surgery relies on stable dilation of the pupil. Automated pupil segmentation from surgical videos can assist surgeons in detecting risk factors for pupillary instability prior to the development of surgical complications. However, surgical illumination variations, surgical instrument obstruction, and lens material hydration during cataract surgery can limit pupil segmentation accuracy. To address these problems, we propose a novel method named adaptive wavelet tensor feature extraction (AWTFE). AWTFE is designed to enhance the accuracy of deep learning-powered pupil recognition systems. First, we represent the correlations among spatial information, color channels, and wavelet subbands by constructing a third-order tensor. We then utilize higher-order singular value decomposition to eliminate redundant information adaptively and estimate pupil feature information. We evaluated the proposed method by conducting experiments with state-of-the-art deep learning segmentation models on our BigCat dataset consisting of 5,700 annotated intraoperative images from 190 cataract surgeries and a public CaDIS dataset. The experimental results reveal that the AWTFE method effectively identifies features relevant to the pupil region and improved the overall performance of segmentation models by up to 2.26% (BigCat) and 3.31% (CaDIS). Incorporation of the AWTFE method led to statistically significant improvements in segmentation performance (P < 1.29  ×  10-10 for each model) and yielded the highest-performing model overall (Dice coefficients of 94.74% and 96.71% for the BigCat and CaDIS datasets, respectively). In performance comparisons, the AWTFE consistently outperformed other feature extraction methods in enhancing model performance. In addition, the proposed AWTFE method significantly improved pupil recognition performance by up to 2.87% in particularly challenging phases of cataract surgery.

Perioperative Management of Antithrombotic Therapy: An American College of Chest Physicians Clinical Practice Guideline

BACKGROUND

The American College of Chest Physicians Clinical Practice Guideline on the Perioperative Management of Antithrombotic Therapy addresses 43 Patients-Interventions-Comparators-Outcomes (PICO) questions related to the perioperative management of patients who are receiving long-term oral anticoagulant or antiplatelet therapy and require an elective surgery/procedure. This guideline is separated into four broad categories, encompassing the management of patients who are receiving: (1) a vitamin K antagonist (VKA), mainly warfarin; (2) if receiving a VKA, the use of perioperative heparin bridging, typically with a low-molecular-weight heparin; (3) a direct oral anticoagulant (DOAC); and (4) an antiplatelet drug.

METHODS

Strong or conditional practice recommendations are generated based on high, moderate, low, and very low certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology for clinical practice guidelines.

RESULTS

A multidisciplinary panel generated 44 guideline recommendations for the perioperative management of VKAs, heparin bridging, DOACs, and antiplatelet drugs, of which two are strong recommendations: (1) against the use of heparin bridging in patients with atrial fibrillation; and (2) continuation of VKA therapy in patients having a pacemaker or internal cardiac defibrillator implantation. There are separate recommendations on the perioperative management of patients who are undergoing minor procedures, comprising dental, dermatologic, ophthalmologic, pacemaker/internal cardiac defibrillator implantation, and GI (endoscopic) procedures.

CONCLUSIONS

Substantial new evidence has emerged since the 2012 iteration of these guidelines, especially to inform best practices for the perioperative management of patients who are receiving a VKA and may require heparin bridging, for the perioperative management of patients who are receiving a DOAC, and for patients who are receiving one or more antiplatelet drugs. Despite this new knowledge, uncertainty remains as to best practices for the majority of perioperative management questions.

Development of a reliable preoperative risk stratification system for phacoemulsification

PURPOSE

To present a statistically validated risk classification system for intraoperative complications in cataract surgery.

SETTING

2nd Department of Ophthalmology, Aristotle University of Thessaloniki, Thessaloniki, Greece.

DESIGN

Prospective observational study.

METHODS

All patients underwent phacoemulsification surgery by experienced, high-volume surgeons for cases with intraoperative complications. The presence of several risk factors was statistically assessed with the help of multiple correspondence analysis to determine the more reliable rank categorization for severity and to calculate a total risk score.

RESULTS

This study included 1572 consecutive patients. The proposed system had 3 risk groups and a no-risk group and had high statistical reliability. A comparison of this system against a previously asserted empirical system showed higher internal reliability.

CONCLUSIONS

Previous efforts to construct a risk classification system for intraoperative complications in cataract surgery have been empirically defined and tested against practice-as-usual. The system in this study quantified risk more accurately and provided an experienced clinician with a reliable means of assessing the preoperational likelihood of intraoperative complications.

Outcomes in resident-performed cataract surgeries with iris challenges: Results from the Perioperative Care for Intraocular Lens study

PURPOSE

To assess the outcomes of resident-performed cataract surgeries with iris challenges and to compare these outcomes with similar surgeries performed by attending surgeons.

SETTING

Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA.

DESIGN

Retrospective chart review.

METHODS

All cases of cataract extraction by phacoemulsification with intraocular lens implantation, performed by comprehensive ophthalmologists between January 1 and December 31, 2014, were reviewed. Cases with preoperative or intraoperative miosis, iris prolapse, and intraoperative floppy iris syndrome, were included for analysis. Visual outcomes and the rate of perioperative adverse events were compared between resident and attending surgeon cases. Factors predicting adverse events were also assessed.

RESULTS

In total, 1931 eye cases of 1434 patients were reviewed, and 65 resident cases and 168 attending surgeon cases were included. The mean logarithm of the minimum angle of resolution corrected distance visual acuity was better in the resident group 1 month after surgery (0.051 ± 0.10 [SD] versus 0.132 ± 0.30, P = .03); however, the difference was eliminated when controlling for macular disease. The mean operative time was 43.8 ± 26.5 minutes and 30.9 ± 12.6 minutes for cases performed by resident surgeons and attending surgeons, respectively (P  .0001). Residents utilized supplemental pharmacologic dilation or retraction more frequently than attending surgeons (98% versus 87% of cases, P = .008). The overall rate of adverse events was no different between residents and attending surgeons (P = 0.16). Dense nuclear sclerosis predicted adverse events in cataract cases with iris challenges (adjusted odds ratio, 1.86; 95% confidence interval, 1.17-2.94; P = .001).

CONCLUSION

Although requiring longer operative times and more surgical manipulation, residents who performed cataract surgeries with iris challenges achieved outcomes comparable to those performed by attending surgeons, and residents should be given the opportunity to operate on these eyes.

Mydriatic insert and intracameral injections compared with mydriatic eyedrops in cataract surgery: controlled studies

Mydriatic eyedrops are the standard method for pupil dilation in cataract surgery, but their limitations have prompted a search for alternative techniques. Two alternatives-an ophthalmic insert containing phenylephrine and tropicamide and intracameral injections of various combinations of lidocaine, cyclopentolate, and phenylephrine, with or without epinephrine in the irrigating solution-have been assessed in prospective controlled studies, including randomized controlled trials (RCTs). We reviewed the safety and efficacy of mydriatic ophthalmic inserts and intracameral mydriatic injections compared with the safety and efficacy of mydriatic eyedrops using a systematic PubMed search (1963 to 2014). We identified 9 prospective studies (7 RCTs, 637 patients) of the mydriatic ophthalmic insert and 15 prospective studies (14 RCTs, 1020 patients) of intracameral mydriatic injections; 7 of the RCTs compared intracameral mydriatic injections and mydriatic eyedrops and 7 RCTs studied the optimum intracameral mydriatic injection protocol. The latter showed that a lidocaine and phenylephrine-based solution, without irrigating epinephrine, was optimum for intracameral mydriatic injections. The mydriatic ophthalmic insert and intracameral mydriatic injections were consistently shown to be safe and as effective as mydriatic eyedrops. Each method has distinct advantages and limitations.

FINANCIAL DISCLOSURE

Dr. Behndig has received fees from Théa Pharma GmbH as a member of the European Team for the Prophylaxis of Infection in Cataract Surgery group. Dr. Korobelnik has received consultancy fees from Alcon Surgical, Inc.; Allergan, Inc.; Alimera, Inc.; Bayer HealthCare AG; Carl Zeiss Meditec AG; Novartis Corp.; Roche Innovatis AG; and Théa Pharma GmbH.

Pupil dilation using drops vs gel: a comparative study

Purpose

To compare the efficacy in pupil dilation and degree of discomfort between topical instillation of mydriatic drops and gel.

Methods

The study included 60 patients with no previous ocular history of trauma and surgery. One eye was dilated with two drops (tropicamide 0.5% and phenylephrine 10%), and the other with one drop of gel (tropicamide 0.5%+phenylephrine 5%). Pupil size was measured by a Colvard pupillometer at baseline and 5, 15, 30, and 45 min following instillation. Pain upon instillation was measured by visual analog scale (VAS).

Results

There was no difference in pupil size at baseline. Use of the gel achieved greater mydriasis than drops (P=0.01), and was also associated with lower pain scores (P=0.003). In diabetic patients, pupil size was smaller at baseline and following instillation of drops and gel. Use of the gel achieved an even greater degree of pupil dilation in this subset of patients than drops (P=0.019).

Conclusions

Gel formulation achieved significantly greater pupil dilation than drops, despite a lower concentration of phenylephrine, and was also associated with significantly lower patient discomfort. This study is the first report of improved mydriatic efficacy in diabetic patients.

Perioperative management of antithrombotic therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This guideline addresses the management of patients who are receiving anticoagulant or antiplatelet therapy and require an elective surgery or procedure.

METHODS

The methods herein follow those discussed in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines article of this supplement.

RESULTS

In patients requiring vitamin K antagonist (VKA) interruption before surgery, we recommend stopping VKAs 5 days before surgery instead of a shorter time before surgery (Grade 1B). In patients with a mechanical heart valve, atrial fibrillation, or VTE at high risk for thromboembolism, we suggest bridging anticoagulation instead of no bridging during VKA interruption (Grade 2C); in patients at low risk, we suggest no bridging instead of bridging (Grade 2C). In patients who require a dental procedure, we suggest continuing VKAs with an oral prohemostatic agent or stopping VKAs 2 to 3 days before the procedure instead of alternative strategies (Grade 2C). In moderate- to high-risk patients who are receiving acetylsalicylic acid (ASA) and require noncardiac surgery, we suggest continuing ASA around the time of surgery instead of stopping ASA 7 to 10 days before surgery (Grade 2C). In patients with a coronary stent who require surgery, we recommend deferring surgery > 6 weeks after bare-metal stent placement and > 6 months after drug-eluting stent placement instead of undertaking surgery within these time periods (Grade 1C); in patients requiring surgery within 6 weeks of bare-metal stent placement or within 6 months of drug-eluting stent placement, we suggest continuing antiplatelet therapy perioperatively instead of stopping therapy 7 to 10 days before surgery (Grade 2C).

CONCLUSIONS

Perioperative antithrombotic management is based on risk assessment for thromboembolism and bleeding, and recommended approaches aim to simplify patient management and minimize adverse clinical outcomes.

Antiplatelet therapy in the perioperative period

The current practice of withdrawing aspirin 7-10 days preoperatively may be dangerous in certain groups of patients. The risk of cardiovascular events increases 3-fold after aspirin withdrawal. The average time between aspirin withdrawal and the manifestation of acute coronary syndrome is 8 to 11 days. The withdrawal of clopidogrel earlier than 4-6 weeks after bare metal stent implantation or less than 12 months after drug-eluting stent implantation is very risky and poses a high risk of stent thrombosis and high perioperative mortality. Continuing aspirin perioperatively leads to a 1.5-fold increase in perioperative bleeding complications but it does not lead to a higher severity of bleeding complications or higher mortality. The article analyzes current European and American guidelines for perioperative antiplatelet treatment and suggests an algorithm based on the guidelines to help make clinical decisions.

Pupil dilation using a standard cataract surgery regimen alone or with atropine 1.0% pretreatment: prospective comparative evaluation

PURPOSE

To compare the amount of pupil dilation produced by a set of commonly used preoperative mydriatic agents for cataract surgery, with the same regimen preceded by topical administration of atropine 1.0%.

SETTING

Department of Ophthalmology, Loma Linda University, Loma Linda, California, USA.

METHODS

In this prospective unmasked study, the baseline pupil size in eyes of volunteers was measured. Pupil size was then measured 30 minutes after instillation of the institution's standard dilation regimen for cataract surgery, which included phenylephrine 2.5%, tropicamide 1.0%, and cyclopentolate 1.0%. Several days later, the subjects returned for repeat measurements after pretreating the study eye(s) with atropine 1.0% 3 times a day the day previously and once on the morning of repeat dilation and measurements. Pupil size was again measured after administration of the standard regimen.

RESULTS

The study included 72 eyes of 54 patients. A paired t test showed a statistically significant difference in mean pupil dilation between the standard regimen alone and the standard regimen with atropine 1.0% pretreatment. The mean pupil dilation was 7.3 mm +/- 1.2 (SD) with the standard regimen alone and 6.9 +/- 1.2 mm with the standard regimen with atropine pretreatment; the difference was statistically significant (P<.001).

CONCLUSION

The addition of atropine 1.0% 1 day before administration of a standard preoperative dilating regimen for cataract surgery resulted in a smaller dilated pupil diameter than administration of the standard set of preoperative mydriatic agents alone.

FINANCIAL DISCLOSURE

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

Hemorrhagic complications from glaucoma surgery in patients on anticoagulation therapy or antiplatelet therapy

PURPOSE

To determine the incidence of and risk factors for hemorrhagic complications in patients on anticoagulation (ACT) or antiplatelet therapy (APT) having glaucoma surgery.

DESIGN

Retrospective case-control study.

METHODS

Medical records of patients who had glaucoma surgery between July 1, 1998 and March 31, 2005 were reviewed. Patients who either used ACT/APT continuously throughout the perioperative period or discontinued its use prior to surgery were compared to case-matched control patients who were not on such therapies. Patients on ACT/APT who experienced postoperative hemorrhagic complications were compared to those who did not. Outcome measures included hemorrhagic complications and thromboembolic events.

RESULTS

Three hundred and forty-seven patients (eyes) who were on ACT or APT prior to glaucoma surgery had a higher rate of hemorrhagic complications than 347 control patients (10.1% vs 3.7%, respectively, P = .002). Patients on ACT had a higher rate of hemorrhagic complications than patients on APT (22.9% vs 8.0%, respectively, P = .003). Patients who continued ACT during glaucoma surgery had the highest rate of hemorrhagic complications (31.8%) when compared to patients who discontinued ACT prior to surgery or patients who used APT alone (P = .001). Hemorrhagic complications following glaucoma surgery were more frequently associated with preoperative ACT, arrhythmia, and higher preoperative and postoperative intraocular pressures (IOP).

CONCLUSION

Chronic ACT/APT was associated with a statistically significant increase in the rate of hemorrhagic complications, and perioperative ACT and a high preoperative IOP are potential risk factors for hemorrhagic complications in patients undergoing glaucoma surgery.

ANTICOAGULATION WITH WARFARIN IN VITREORETINAL SURGERY

PURPOSE

To describe the clinical course of patients undergoing vitreoretinal procedures while receiving systemic anticoagulation with warfarin.

METHODS

We reviewed patient demographics, ocular findings, and clinical courses for 25 patients receiving systemic anticoagulation with warfarin who subsequently underwent vitreoretinal surgery.

RESULTS

Patient ages ranged from 49 years to 81 years (median, 69 years). Indications for anticoagulation included atrial fibrillation, cerebrovascular disease, deep vein thrombosis, prosthetic heart valves, and hypercoagulable state. Follow-up ranged from 4 months to 36 months (median, 19.5 months). The international normalized ratio ranged from 1.5 to 3.1 (median, 2.0). Final vision after surgery ranged from 20/20 to 20/400 (median, 20/100). One patient who underwent scleral buckling and external drainage of subretinal fluid had an intraoperative subretinal hemorrhage associated with the drainage procedure. In all other patients, no intraoperative complications occurred.

CONCLUSION

Cessation of therapy with warfarin may not be necessary in patients receiving anticoagulation who are undergoing vitreoretinal procedures. Successful visual and anatomical results may be achieved after vitreoretinal surgery for patients receiving anticoagulation with warfarin. The management of anticoagulation should occur in conjunction with the patient's internist to allow a clear understanding of the potential systemic risks of cessation of warfarin treatment preoperatively.

Discontinuation of perioperative antiplatelet and anticoagulant therapy in stroke patients

Growing evidence suggests that perioperative withdrawal of ASA for secondary stroke prevention increases thromboembolic risk without the associated benefit of decreased bleeding complications. ASA maintenance is acceptable in many procedures, including invasive ones. Many procedures, in particular ophthalmologic, dermatologic, and dental surgeries, also are safe while continuing oral AC. Warfarin has been continued successfully even in some surgeries that have high bleeding risk. When the risk is too high, temporary bridging therapy with LWMH is safe in many populations. Although the exact thromboembolic risks associated with temporary cessation of AP and AC are unknown and likely low, morbidity and mortality associated with thromboembolism are high. Further studies investigating the risks and benefits of maintaining AP and AC during procedures, particularly invasive ones, are needed. Meanwhile, it is critical that physicians understand the risks and benefits of perioperative AP and AC and the variety of procedures in which these agents can be safely continued.

Results of combined phacoemulsification and trabeculectomy with mitomycin C in pseudoexfoliation versus non-pseudoexfoliation glaucoma

BACKGROUND

This study was conducted to evaluate the rate of intraoperative and postoperative complications and the outcome of combined phacoemulsification (phaco) with posterior chamber (PC) intraocular lens (IOL) and trabeculectomy in patients with pseudoexfoliation (PXF) versus non-pseudoexfoliation (non-PXF) glaucoma.

METHODS

One hundred and four eyes of 88 patients with combined phaco, PC IOL and trabeculectomy with mitomycin C (MMC) were included in the study. MMC 0.02% was applied for 1 min in all cases. Main outcome measures were rate of intraoperative and postoperative complications, intraocular pressure (IOP) and visual acuity (VA). Success rates were determined via Kaplan-Meier survival analysis. Surgical success for both groups was defined as IOP being less than 21 mmHg with no treatment or less than 16 with one topical pressure-reducing agent allowed.

RESULTS

The PXF group included 55 (52.9%) eyes and the non-PXF group 49 (47.1%) eyes. Transition to extracapsular cataract extraction (ECCE) occurred in 12.7% of the PXF group, and in 6.1% of the non-PXF group (P=0.16). The occurrence of vitreous loss did not differ significantly between the groups. Patients of both groups had a significant IOP reduction after surgery (P=0.0001). At the end of postoperative follow-up, the success rate approached 83.6% in the PXF group and 83.7% in the non-PXF group. The most common postoperative complications were hyphema (14.5%) in the PXF group and fibrin (14.3%) in the non-PXF group.

CONCLUSIONS

Although transition to ECCE was more frequent in the PXF than in the non-PXF group, there was no significant difference in the rate of complications between PXF and non-PXF eyes.

Objective Assessment of Skills in Intraocular Surgery (OASIS)

OBJECTIVE

To establish an objective ophthalmic surgical evaluation protocol to assess residents' surgical competency and improve residents' surgical outcomes.

PARTICIPANTS

Eight experts in resident education from comprehensive ophthalmology, cornea, glaucoma, and retina services; 2 chief residents (postgraduate year 5 [PGY5]); and resident representatives from PGYs 2, 3, and 4 participated in the development of an objective assessment tool of skills in resident cataract surgery.

METHODS

Analysis of all resident cataract surgeries performed at our service from July 2001 to July 2003 led to the development of a 1-page objective evaluation form to assess residents' skills in cataract surgery. A panel of surgeons at the Massachusetts Eye and Ear Infirmary reviewed the database and the evaluation form and provided constructive feedback.

RESULTS

Development of a unique database of all resident cataract cases and constructive feedback by experts in resident teaching assisted in creating a 1-page evaluation form entitled Objective Assessment of Skills in Intraocular Surgery (OASIS).

CONCLUSIONS

OASIS has face and content validity and can be used to assess, objectively, surgical events and surgical skill. We believe the OASIS evaluation form and database will be a valuable tool for assessing ophthalmology residents' surgical skills at other residency programs as well.

Low-dose aspirin for secondary cardiovascular prevention - cardiovascular risks after its perioperative withdrawal versus bleeding risks with its continuation - review and meta-analysis

OBJECTIVES

Low-dose aspirin given for secondary prevention of cardiovascular disease is frequently withdrawn prior to surgical or diagnostic procedures to reduce bleeding complications. This may expose patients to increased cardiovascular morbidity and mortality. Aim of the study was to review and quantify cardiovascular risks because of periprocedural aspirin withdrawal and bleeding risks with the continuation of aspirin.

METHODS

We screened MEDLINE (January 1970-October 2004) with additional manual cross-referencing for clinical studies, surveys on the opinions of doctors and guidelines.

RESULTS

Studies reporting the relative risk of acute cardiovascular events after aspirin withdrawal when compared with its continuation were not found. However, retrospective investigations revealed that aspirin withdrawal precedes up to 10.2% of acute cardiovascular syndromes. The time interval between discontinuation and acute cerebral events was 14.3 +/- 11.3 days, 8.5 +/- 3.6 days for acute coronary syndromes, and 25.8 +/- 18.1 days for acute peripheral arterial syndromes (P < 0.02 versus acute coronary syndromes). On aspirin-related bleeding risks, we obtained 41 (12 observational retrospective, 19 observational prospective, 10 randomized) studies, reporting on 49 590 patients (14 981 on aspirin). Baseline frequency of bleeding complications varied between 0 (skin lesion excision, cataract surgery) and 75% (transrectal prostate biopsy). Whilst aspirin increased the rate of bleeding complications by factor 1.5 (median, interquartile range: 1.0-2.5), it did not lead to a higher level of the severity of bleeding complications (exception: intracranial surgery, and possibly transurethral prostatectomy). Surveys amongst doctors on the management of this problem demonstrate wide variations. Available guidelines are scarce and in part contradictory.

CONCLUSIONS

Only if low-dose aspirin may cause bleeding risks with increased mortality or sequels comparable with the observed cardiovascular risks after aspirin withdrawal, it should be discontinued prior to an intended operation or procedure. Controlled clinical studies are urgently needed.

Risks and benefits of anticoagulant and antiplatelet medication use before cataract surgery

OBJECTIVE

To estimate the risks and benefits associated with continuation of anticoagulants or antiplatelet medication use before cataract surgery.

DESIGN

Prospective cohort study.

PARTICIPANTS

Patients 50 and older scheduled for 19,283 cataract surgeries at nine centers in the United States and Canada between June 1995 and June 1997.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Intraoperative and postoperative (within 7 days) retrobulbar hemorrhage, vitreous or choroidal hemorrhage, hyphema, transient ischemic attack (TIA), stroke, deep vein thrombosis, myocardial ischemia, and myocardial infarction.

RESULTS

Before cataract surgery 24.2% and 4.0% of patients routinely used aspirin and warfarin, respectively. Among routine users, 22.5% of aspirin users and 28.3% of warfarin users discontinued these medications before surgery. The rates of stroke, TIA, or deep vein thrombosis were 1.5/1000 among those who did not use aspirin or warfarin and 3.8/1000 surgeries among routine users of aspirin and warfarin who continued their medication before surgery. The rate was 1 event per 1000 surgeries among those who discontinued aspirin use (relative risk = 0.7, 95% confidence interval = 0.1-5.9). There were no events among warfarin users who discontinued use. The rates of myocardial infarction or ischemia were 5.1/1000 surgeries (aspirin) and 7.6/1000 surgeries (warfarin) among routine continuous users and no different from those of routine users who discontinued use.

CONCLUSIONS

The risks of medical and ophthalmic events surrounding cataract surgery were so low that absolute differences in risk associated with changes in routine anticoagulant or antiplatelet use were minimal.

A comparison of anterior chamber and posterior chamber intraocular lenses after vitreous presentation during cataract surgery: the Department of Veterans Affairs Cooperative Cataract Study

PURPOSE

To compare the efficacy and safety of anterior chamber (AC) intraocular lenses (IOLs) and posterior chamber (PC) IOLs implanted after vitreous presentation during extracapsular cataract extraction (ECCE).

DESIGN

The study was a prospective, long-term, randomized clinical trial conducted at 19 Department of Veterans Affairs medical centers across the United States.

METHODS

There were 438 eyes (438 patients) that met preliminary eligibility criteria, suffered vitreous presentation during ECCE (phacoemulsification or classical extracapsular technique), and had sufficient capsular support for a PC IOL without sutures after anterior vitrectomy randomized to either a PC IOL (230 patients) or an AC IOL (208 patients). Patients were examined at 3, 6, and 12 months post-surgery and yearly thereafter. Minimum follow-up was 1 year. The primary outcome measure of best-corrected visual acuity at 1 year was obtained by a masked certified examiner.

RESULTS

More PC IOL patients (91%) achieved visual acuity of 20/40 or better at 1 year than AC IOL patients (79%), a highly significant difference (P =.003). There was no significant difference between the two groups for patient's rating of vision or adverse events. Over 84% of the PC IOL patients and over 77% of the AC IOL patients rated their vision as good or better at 1 year as opposed to only 7% giving such ratings before surgery. For at least one rating period during the first year, 13.2% of the combined study patients had cystoid macular edema, 8.5% had posterior capsule opacification, 5.7% had glaucoma, and 3.7% had retinal detachment.

CONCLUSION

In the presence of sufficient capsular support, a PC IOL should be implanted after vitreous presentation during ECCE.

Macular translocation with 360 degree retinotomy for management of age-related macular degeneration with subfoveal choroidal neovascularization

PURPOSE

The aim of this study is to evaluate the functional outcome in a group of patients treated with full macular translocation (FMT) with 360-degree retinotomy for treatment of age-related macular degeneration (ARMD) with subfoveal choroidal neovascularization.

DESIGN

Consecutive interventional case series.

METHODS

Fifty consecutive eyes (50 patients) with ARMD and subfoveal neovascularization who underwent a FMT in our department from January 1999 to July 2000 are included in this study. Compensatory muscle surgery, as described by Eckardt and associates, was performed on all the eyes. The median follow-up is 21 months (range, 12 to 36; SD, 5.4).

RESULTS

The best-corrected postoperative visual acuity (BCVA) was improved by 2 or more Snellen lines in 33 eyes (66%) and remained stable (+/-1 line) in 14 eyes (28%). Only 3 eyes (6%) experienced a deterioration of the BCVA of 2 or more lines. The final BCVA was 20/50 or better in 32% of the cases; only 8 eyes (16%) had a final BCVA < 20/200. Thirty-four (68%) patients are able to read newspaper print (3.3/10) with normal (+3 diopters to +4 diopters) or increased (+5 diopters to +8 diopters) reading ads. Other patients are able to read with magnifying systems. Complications included proliferative vitreoretinopathy (PVR) in 9 eyes (18%), recurrent choroidal neovascularization in 5 eyes (10%), diplopia in 3 eyes (6%), choroidal hemorrhage in 2 eyes (4%), macular hole in 1 eye, and temporary hypotony in 1 eye.

CONCLUSIONS

As 68% of the patients in the study group regained reading vision with reading glasses, FMT can be considered an effective approach in cases of subfoveal choroidal neovascularization. Further investigations are necessary to determine which patients will have the most benefit from this complex therapeutic method.

The early complications of cataract surgery: is routine review of patients 1 week after cataract extraction necessary?

OBJECTIVE

This study sought to define the nature and frequency of complications present 1 week after cataract surgery, to determine whether these complications are predictable, and to ascertain if patients undergoing cataract surgery require routine review at this time.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

One thousand consecutive patients undergoing cataract removal by either phacoemulsification or extracapsular extraction at a large teaching hospital between January 1996 and May 1998. Patients with both complicated and uncomplicated histories and surgeries were included.

MAIN OUTCOME MEASURES

Nature and frequency of complications present 1 week after cataract surgery.

RESULTS

At the routine 1-week visit, postoperative complications were observed in 41 of 1000 patients (4.1%). Twenty-one (51%) of these patients had a completely unremarkable history to that point, and whereas only four (19%) were symptomatic, 20 (95%) required a change to their postoperative management. The most significant unexpected complications were uveitis (seven cases), cystoid macular edema (four cases), and vitreous to the wound, exposed knots, and loose suture (one case of each). Complications were present in 20 of 257 (7.8%) patients with a preoperative or surgical risk factor, and there was a significant relationship between preoperative (P = 0.02), and combined preoperative and intraoperative risk factors (P = 0.001), and complications present at the 1-week review. The relationship between surgical risk factors and 1-week complications was not significant (P = 0.07). There were coexistent pathologic features in 19% of all eyes. Registrars performed 38% of surgeries, and 96% of cataracts were removed by phacoemulsification. Operative complications occurred in 6.7% of patients, most commonly a posterior capsule tear (4.4% of all cases). Complications were observed in 10% of eyes on the first postoperative day. Raised intraocular pressure was the complication in 88% of these patients.

CONCLUSIONS

This study provides an overview of modern cataract surgery in a large teaching hospital and indicates that abandonment of routine 1-week review may result in the failure to detect significant postoperative complications.

Anticoagulation and cataract surgery: a review of the current literature

The anticoagulated patient presenting for cataract surgery presents many dilemmas for anaesthetist and surgeon alike. Current evidence suggests that warfarin therapy significantly improves prognosis in patients with atrial fibrillation with coexisting cerebrovascular disease, and those with non-tissue prosthetic heart valves. Inadequate anticoagulation in these groups exposes them to higher risk of systemic embolic complications, which are frequently devastating. Warfarin is an extremely complex drug. Attempted cessation and recommencement of warfarin therapy may not only reverse anticoagulation for unpredictable periods of time but may also expose patients to a transient yet dangerous hypercoagulable state. In most instances this state represents an additive risk to the untreated disease for which warfarin is being prescribed. It is difficult to accurately measure risks of local anaesthetic blockade in anticoagulated patients as techniques are not standardized. Smaller needles and single injections appear safer with deep eye blocks, while sub-Tenon's block and topical techniques appear safer still, and acceptable provided patients and surgeons are happy with the conditions so created. Retrobullbar haemorrhage appears to occur more frequently in anticoagulated patients who have their anticoagulation continued up to the time of cataract surgery. Retrobulbar haemorrhage is also more frequent in this same group even when anticoagulation is ceased prior to surgery when compared to non-anticoagulated patients. Prognosis for visual acuity with retrobulbar haemorrhage is generally good, given an experienced surgeon is present to rapidly decompress the eye.

Exfoliation syndrome

Exfoliation syndrome (XFS) is an age-related disease in which abnormal fibrillar extracellular material is produced and accumulates in many ocular tissues. Its ocular manifestations involve all of the structures of the anterior segment, as well as conjunctiva and orbital structures. Glaucoma occurs more commonly in eyes with XFS than in those without it; in fact, XFS has recently been recognized as the most common identifiable cause of glaucoma. Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma. There is increasing evidence for an etiological association of XFS with cataract formation, and possibly with retinal vein occlusion. XFS is now suspected to be a systemic disorder and has been associated preliminarily with transient ischemic attacks, stroke, systemic hypertension, and myocardial infarction. Further ramifications await discovery. Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS. The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated. Whereas the classic picture of manifest XFS has been often described, the early stages of beginning exfoliation have not been well defined. Next to the lens, exfoliation material is most prominent at the pupillary border. Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS. Despite extensive research, the exact chemical composition of exfoliation material (XFM) remains unknown. An overproduction and abnormal metabolism of glycosaminoglycans have been suggested as one of the key changes in XFS. The protein components of XFM include both noncollagenous basement membrane components and epitopes of the elastic fiber system such as fibrillium. Regardless of etiology, typical exfoliation fibers have been demonstrated electron microscopically in close association with the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium, the iris pigment epithelium, the corneal endothelium, the trabecular endothelium, and with almost all cell types of the iris stroma, such as fibrocytes, melanocytes, vascular endothelial cells, pericytes, and smooth muscle cells. The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction. Heightened awareness of this condition and its associated clinical signs are important in the detection and management of glaucoma, and preoperative determination of those patients at increased risk for surgical complications.

Risk factors for vitreous loss in cataract surgery

PURPOSE

To evaluate the risk factors for posterior capsule rupture with or without vitreous loss (PCR +/- VL) in extracapsular cataract extraction (ECCE).

METHODS

The charts of 2794 consecutive patients who had ECCE with or without intraocular lens implantation between January 1992 and December 1997 were reviewed retrospectively. Probable risk factors included age, sex, operated eye (right or left), presence of diabetes mellitus, systemic hypertension, history of vitreous loss in the other eye (if operated), type of cataract, axial length of the eye, preoperative visual acuity, glaucoma, presence of pseudoexfoliation, preoperative shallow anterior chamber and experience of surgeon (resident, general ophthalmologist, cataract surgeon). We compared 192 patients who had PCR +/- VL with complete data and 275 randomly selected patients who had no complications, using multiple logistic regression analysis.

RESULTS

Two hundred and fifty-four patients (9.09%) had PCR and 197 (7.05%) had PCR + VL. The surgeon's experience (p < 0.0005), glaucoma (p < 0.005), type of cataract (p < 0.005), presence of pseudoexfoliation (p < 0.05) and systemic hypertension (p < 0.05) were significant risk factors.

CONCLUSIONS

Patients with risk factors such as glaucoma, pseudoexfoliation, traumatic cataract and systemic hypertension should be operated by experienced surgeons.

Effect of aspirin intake on bleeding during cataract surgery

PURPOSE

To study the association between chronic intake of aspirin and intraoperative bleeding during cataract surgery and the effect of discontinuing the medication before surgery.

SETTING

Department of Ophthalmology, Meir Hospital, Sapir Medical Center, Kfar-Saba, Israel.

METHODS

Sixty-one patients having cataract surgery and receiving aspirin to prevent thromboembolic events were divided into 3 groups: Group A, continuation of the medication; Group B, cessation of aspirin intake for 2 to 5 days before surgery; Group C, cessation of medication for 7 to 10 days before surgery. Blood tests of coagulation parameters, a detailed questionnaire, and 1 day and 1 week follow-up were evaluated.

RESULTS

There were no significant differences in blood tests and the amount and incidence of intraoperative bleeding among the 3 groups. Diathermy was used somewhat more in Group A; however, there was no difficulty stopping the bleeding in any case and discontinuation of the medication had no effect on the intraoperative course or postoperative outcome.

CONCLUSIONS

Aspirin intake was not associated with significant intraoperative bleeding; thus, discontinuation of aspirin is usually not indicated. Clear corneal phacoemulsification is advantageous in patients receiving antiplatelet therapy.

Cataract surgery in a Swedish population: observations and complications

PURPOSE

To describe relevant clinical conditions at cataract surgery in a defined Swedish population, examine variables and their influence on the operative procedure, and estimate the risk of complications at surgery.

SETTING

Department of Ophthalmology, Lund University Hospital, Sweden.

METHODS

Using the Cataract Analysis System, data were prospectively collected on 5878 consecutive cataract surgeries performed in a single Swedish health care district from 1986 to 1990. Patients younger than 15 years were not included. The study population was complete enough to represent all cataract surgeries in the referral region of the Lund Health Care District during this period. The incidence of zonular or lens capsule rupture at surgery was used as a measure of surgical complications and assessed as a function of other preoperative and surgical parameters. A logistic regression model was used to assess the probability of complications at surgery.

RESULTS

Glaucoma was the highest statistically significant preoperative risk factor for capsular or zonular rupture at surgery, with or without vitreous loss, with a relative risk of 2.7 (i.e., a 2.7-fold increase in risk over patients without glaucoma). Surgeons performing fewer than 40 operations in 5 years had a relative risk of zonular or capsular rupture of approximately 2.9 (i.e., a 2.9-fold increase in risk over high-volume surgeons). The overall risk was 2.5%.

CONCLUSION

Cataract patients with glaucoma have an increased risk of complications at surgery. Surgeons performing few operations tended to have more capsular or zonular ruptures.