Microbiologic analysis of aqueous humor in phacoemulsification.

PURPOSE: This study was designed as a microbiologic survey of the fluids aspirated from the anterior chamber at the end of cataract extraction performed by phacoemulsification, and to correlate the contamination rate of the anterior chamber to the surgical technique used. METHODS: One hundred and one consecutive patients (126 eyes) who underwent cataract extraction by phacoemulsification and posterior chamber intraocular lens implantation were included in the study. Microscopical examination, culture, and determination of the number of colonies were carried out on the bacteria and fungi in the anterior chamber fluids aspirated at the end of surgery, before final suture placement. RESULTS: Anterior chamber fluids yielded positive cultures in nine specimens (8.14%), six of which were identified as coagulase-negative staphylococci. Quantification disclosed colony counts ranging between 2-10 and 10-40 per mL. CONCLUSIONS: Preliminary results in a small population show that the contamination of the aqueous humor is significantly less frequent if the cataract extraction is performed by phacoemulsification.     

Bacterial contamination: epidemiology in cataract surgery

PURPOSE: To evaluate anterior chamber (AC) bacterial contamination at the end of cataract surgery in a large series of patients, to determine the influence of operative technique on ocular contamination. METHODS: Retrospective study of 2,624 patients undergoing cataract extraction, 354 extracapsular cataract extraction (ECCE) and 2,270 phacoemulsification. Anterior chamber aspirates were performed on completion of surgery for microbiological studies. RESULTS: One hundred and thirty two patients (5%) had culture-positive anterior chamber aspirates. Coagulase-negative Staphylococcus, Propionibacterium sp. and Corynebacterium sp. were the most commonly isolated organisms. The AC contamination rates during ECCE (5.6%) and phacoemulsification (4.7%) were not statistically different. There was a statistically significantly higher risk of AC contamination in eyes receiving an intraocular lens (IOL) with polypropylene haptics (9.9%) than in eyes receiving the same IOL with polymethylmethacrylate haptics (4.4%). CONCLUSION: Surgical technique had no statistically significant effect on ocular contamination. Polypropylene haptics IOLs were associated with a higher risk of bacterial contamination.     

Bacterial contamination of the anterior chamber during phacoemulsification cataract surgery

PURPOSE: To determine the incidence of bacterial contamination of the anterior chamber after phacoemulsification cataract surgery with intraocular lens (IOL) implantation. SETTING: Department of Ophthalmology, Royal Prince Alfred Hospital, Sydney, Australia. METHODS: Ninety-eight consecutive eyes of 96 patients having phacoemulsification cataract surgery with IOL implantation were included in this prospective study. Two intraoperative anterior chamber aspirates were obtained from each patient, 1 taken at the start and the other at the conclusion of surgery. In addition, preoperative and postoperative conjunctival swabs were acquired. The 4 specimens were cultured using direct culturing techniques under aerobic and anaerobic conditions for 14 days. No preoperative antibiotics were used. RESULTS: The incidence of intraoperative anterior chamber contamination was 0% (95% confidence interval, 0%-3.7%) as all intraoperative anterior chamber samples proved culture negative. Sixty-five percent of the preoperative conjunctival swabs were positive for growth, with corynebacteria, coagulase-negative staphylococci, and Propionibacterium acnes being the most frequently cultured organisms. Sixteen percent of the postoperative conjunctival swabs were positive for growth, with corynebacteria and coagulase-negative staphylococci being the most common bacteria. One patient developed culture-positive postoperative endophthalmitis; using pulsed-field gel electrophoresis for further typing, the implicated Staphylococcus epidermidis was indistinguishable from that isolated from the patient's preoperative conjunctival swab. CONCLUSIONS: The bacterial contamination rate of the anterior chamber after phacoemulsification and IOL implantation was extremely low. Additional findings support the conjunctiva as being a primary source of bacteria causing postoperative endophthalmitis as well as the ability of povidone-iodine to reduce the conjunctival bacterial load.     

Prospective evaluation of external ocularmicrobial growth and aqueous humor contamination during cataract surgery

Purpose:To analyze the route of aqueous humor contamination leading to thedevelopment of postoperative endophthalmitis.Setting:Department of Ophthalmology, University of Helsinki, Finland.Methods:Forty-nine eyes of 49 patients (31 having phacoemulsification and 18 extracapsularcataract extraction [ECCE]) participated in the study. Four bacterial cultures were taken: preoperative conjunctival swab, lid margin culture, intraoperative lacrimal lake sample, and immediate postoperative anterior chamber fluid sample.Results:Preoperative lid margin cultures were positive in 59.2% of eyes, conjunctival cultures in 69.4%, and lacrimal lake cultures in 24.9%. Four aqueous humor samples (8.2%) showed bacterial growth in the anterior chamber aspirate: 3 in the phacoemulsification and 1 in the ECCE group. The bacteria isolated in this study, Staphylococcus epidermidis and Propionibacterium acnes (2 positive isolates each) were sensitive to the preoperative topical antibiotics used. No aqueous humor sample or any from other locations showed gram-negative microbe growth. The most frequently recovered microbes in all samples collected from the 3 other sources were S epidermidis and other coagulase-negative staphylococcus species, followed by P acnes and other propionibacterium species, Staphylococcus aureus, and diptheroids.Conclusion:The ocular surface significantly contributed fo the transmission ofmicrobes into the eye during cataract surgery. These microbes could not be eradicated by topical preoperative antibiotics. However, no patient developed postoperative endophthalmitis. Natural defense mechanisms appear to fend off a minor inoculum with these microbes of relatively low pathogenicity.     

Bacterial contamination of anterior chamber during IOL surgery

PURPOSE: To study the nature and frequency of bacterial contamination during cataract surgery. METHODS: The preoperative smears from the conjunctiva and anterior chamber (AC) fluid aspirates during extra-capsular cataract surgery (ECCE) with posterior chamber intraocular lens (PCIOL) implantation in 40 eyes were analysed for aerobic and anaerobic bacteria. Any change in the bacterial strains isolated before and after cataract surgery was also studied. RESULTS: AC fluid aspirates were positive for bacteria in 15 eyes (37.5%). Coagulase-negative Staphylococcus was the most common aerobe (39.4%) and Propionibacterium acnes the most common anaerobe. Of the 15 cases with positive AC fluid cultures, 6 showed an organism in the AC aspirate different from the conjunctival smear. CONCLUSION: Clinically there was no endophthalmitis in any of the eyes. Factors such as preoperative antibiotic use, the antibacterial properties of aqueous, or low inoculum size could explain this. The preoperative conjunctival smear may not be useful in predicting the AC fluid contamination or outcome of cataract surgery.     

Intraocular contamination during extracapsular cataract extraction with intraocular lens implantation

Ocular bacterial contamination has been studied in 45 eyes that underwent cataract surgery. The following samples were taken: (1) eyelid margin swab; (2) conjunctival swab; (3) aqueous humor after initial anterior chamber penetration; (4) anterior capsule fragment after capsulorrhexis or capsulotomy; (5) cortical lens material; (6) anterior chamber fluid after lens implantation. The percentages of contaminated samples were 15.5, 13.3, 0.0, 11.1, 13.3 and 6.6, respectively. There was a significant difference between the incidence of positive cultures in the aqueous humor at the time of incision and in subsequent intraocular samples. Positive cultures were found in 13 out of 45 eyes, only gram-positive organisms were recovered and coagulase-negative staphylococci were the most common (78.5% of the isolates). These results confirm previous reports on intraocular contamination during cataract surgery.     

Microbial contamination of the anterior chamber during phacoemulsification

PURPOSE: To study the nature and frequency of anterior chamber contamination during phacoemulsification. SETTING: Department of Ophthalmology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India. METHODS: Eighty eyes of 80 patients having routine phacoemulsification cataract surgery were recruited into this prospective study. Bacterial cultures from the intraoperative anterior chamber aspirates from the patients were assessed. RESULTS: Anterior chamber fluid aspirates were positive for bacteria in 37 eyes (46.25%). Coagulase-negative Staphylococcus was the most common aerobe and Propionibacterium acnes, the most common anaerobe. CONCLUSION: Results indicate that phacoemulsification has no proven advantage over conventional extracapsular cataract extraction in reducing intraoperative bacterial contamination.     

Anterior chamber aspirate cultures after uncomplicated cataract surgery

We cultured anterior chamber aspirates of 30 patients who had uncomplicated extracapsular cataract extraction or phacoemulsification. The aspirate was obtained at the time of wound closure. Of 30 patients, 13 (43%) had culture-positive anterior chamber aspirates. The total number of organisms recovered was 18, with three patients having multiple organisms identified. The most commonly isolated organisms were coagulase-negative Staphylococcus sp., occurring in eight of 18 isolates (44%). No eyes in our study developed endophthalmitis, even though almost one half had viable organisms growing from the anterior chamber aspirates. Inoculum sizes were extremely small (10 to 20 colony-forming units/ml). This study suggests that in humans, the anterior chamber is capable of clearing a low inoculum of bacteria after cataract surgery without the development of endophthalmitis.     

兔眼后房型人工晶体置入后房水内丙二醛测定

应用ＴＢＡ荧光法检测了兔眼单纯晶体囊外摘除后和晶体囊外摘除并后房型人工晶体置入后房水内丙二醛含量，这二种手术后房水内丙二醛含量比正常眼显著增高（Ｐ＜０．００５，Ｐ＜０．００１）。结果提示前房内发生了脂质过氧化反应，这一发现有利于对眼内后房型人工晶体表面细胞反应及前膜形成进一步认识。     

糖尿病白内障人工晶状体植入术临床分析

目的分析基层医院开展糖尿病白内障摘出联合后房型人工晶状体植入术的临床疗效。方法我们对46例(46眼)糖尿病白内障行现代囊外摘出联合后房型人工晶状体植入术，并设46例(46眼)老年性白内障患者行现代囊外摘出联合后房型人工晶状体植入术为对照。结果糖尿病白内障术后角膜内皮水肿、房水浑浊、纤维素样渗出、瞳孔后粘连、后囊浑浊等眼前段手术并发症发生率高于老年性白内障，但经正确有效处理，总体预后两组并无显著差异。结论糖尿病患者空腹血糖控制在8．0mmol／L以下，行白内障摘出后房型人工晶状体植入是安全的。     

Peroperative microbial contamination of anterior chamber aspirates during extracapsular cataract extraction and phacoemulsification

BACKGROUND—The normal conjunctival flora is one of the main sources of intraocular contamination during cataract surgery. The theory that the positive anterior chamber (AC) pressure during phacoemulsification (phaco), and the smaller wound utilised, might reduce the rate of contamination was studied.
METHODS—The peroperative AC aspirates of 210 consecutive patients undergoing cataract surgery were assessed. In group 1, 100 patients underwent a standard extracapsular cataract extraction (ECCE). In group 2, 110 patients underwent phacoemulsification of the crystalline lens through a scleral tunnel. AC aspirates from the Simcoe irrigation/aspiration cannula (group 1) and phaco probe (group 2) were collected and microbiological studies performed after direct and enrichment cultures.
RESULTS—There were 29 (29%) positives in the ECCE group compared with 22 (20%) positive cultures from AC aspirates in the phaco group. Coagulase negative staphylococcus (CNS) was the commonest contaminant in both groups.
CONCLUSION—Although there was a higher rate of AC contamination during ECCE, the difference was not statistically significant (p> 0.10, χ²=2.31).

     

后囊缺陷性白内障超声乳化术的临床观察

目的:探讨后囊缺陷性白内障手术方式,比较超声乳化技术和囊外摘除技术的安全性和效果。方法:回顾性分析后囊缺陷性白内障患者33例40眼的手术效果,囊外摘除手术组(ECCE组)10例12眼、超声乳化手术组(Phaco组)23例28眼。结果:后囊破裂+玻璃体脱出:ECCE组为3眼(25%),Phaco组为3眼(11%),两组比较有显著性差异(P<0.05)。术后矫正视力提高≥2行者:ECCE组为10眼(83%),Phaco组为26眼(93%),两组比较有显著性差异(P<0.05)。结论:对于后囊缺陷性白内障患者,超声乳化手术的安全性和效果优于囊外手术。超声乳化手术中,始终保持前房的稳定,不行水分离、在低流量、低负压、低能量下进行,正确处理后极部皮质与后囊膜的关系是手术成功的关键。     

Anterior chamber inflammation following cataract surgery in patients with non-insulin-dependent diabetes mellitus

PURPOSE: The aim of the study was to estimate the early breakdown of the blood-aqueous barrier (BAB) following uneventful cataract surgery in patients with non-insulin dependent diabetes mellitus. MATERIAL AND METHODS: Aqueous flare was estimated in 54 diabetic eyes before and after cataract surgery. Fifteen eyes underwent uneventful ECCE (extracapsular cataract extraction with "can opener" capsulotomy) and 39 phacoemulsification with continuous curvilinear capsulorhexis. All procedures were performed by experienced surgeons. Fifty six eyes of age-matched healthy patients undergoing uncomplicated cataract surgery served, as control. Anterior chamber flare was quantified preoperatively, 1 and 3 days postoperatively, using laser-flare meter (Kowa FM-500). Laser flare values were expressed in photon counts/millisecond. RESULTS: Mean preoperative anterior chamber flare in diabetes type 2 was as follows: normal fundus--6.7, background retinopathy--8.6 and proliferative retinopathy--14.1 (p < 0.01 vs NF group). Significantly lower anterior chamber flare measurements following phacoemulsification (25.0-1 day, 17.8-3 days post surgery), than after ECCE (63.7 and 45.6, respectively) (p < 0.01) were observed in diabetic eyes. In phaco group, we noted lower flare values in eyes without retinopathy; 25.2-1 day, 14.0-3 days post surgery, than in proliferative retinopathy (31.5 and 28.4, respectively) (p < 0.05 vs no retinopathy group). CONCLUSIONS: Phacoemulsification, as a less traumatising technique produces less BAB breakdown and seems to be more suitable than ECCE in diabetic eyes. Following phacoemulsification, eyes with proliferative retinopathy had significantly higher flare values than eyes without retinopathy.     

Microbiological profile of anterior chamber aspirates following uncomplicated cataract surgery

Anterior chamber aspirate cultures were done for 66 patients who underwent either an uncomplicated intracapsular cataract extraction, extracapsular cataract extraction with posterior-chamber intraocular lens implantation, or phacoemulsification with posterior-chamber intraocular lens implantation. The aspirate was obtained at the time of wound closure. The aspirates were immediately transferred to the microbiology laboratory where one drop of the aspirate was placed on a glass slide for gram stain, and the remainder was unequally divided and inoculated into blood agar, chocolate agar and thioglycolate broth. The cultures were incubated at 37 degrees C with 5% CO2 and held for 5 days. Of 66 patients 4 (6%), had smear-positive anterior chamber aspirates. None of the aspirates showed any growth on any of the 3 culture media used. None of the eyes in the study developed endophthalmitis. This study concludes that there is no contamination of the anterior chamber by viable bacteria after cataract surgery, irrespective of the mode of intervention.     

Postoperative inflammation: extracapsular cataract extraction versus phacoemulsification.

PURPOSE: To quantitatively compare postoperative inflammation after extracapsular cataract extraction (ECCE) with that after phacoemulsification in an Asian population. SETTING: Singapore National Eye Center, Singapore. METHODS: In this prospective, randomized, double-masked clinical trial, patients having cataract surgery were randomized to receive ECCE (n = 16) or phacoemulsification (n = 18). Diabetics were excluded. Two surgeons performed both types of surgery and implanted a 6.0 mm optic intraocular lens. Inflammation was assessed qualitatively by slitlamp grading of cells and flare and quantitatively using the Kowa flare meter. One independent postoperative investigator performed the slitlamp examination and laser flare meter readings. RESULTS: The ECCE and phacoemulsification groups were comparable (P > .05) in age, sex, ethnicity, and preoperative flare levels. The combined slitlamp inflammatory scores (anterior chamber cells and flare) and mean laser flare meter readings showed the ECCE group had significantly higher mean flare measurements than the phacoemulsification group at days 4 (P = .0012), 8 (P = .0013), 15 (P = .0013), 30 (P = .0004), and 60 (P = .0164). Flare levels in the ECCE group returned to preoperative values by the second month; the phacoemulsification group achieved preoperative levels by 1 month. The clinical inflammatory assessment score correlated closely to the flare level readings. CONCLUSION: Phacoemulsification induced less inflammation than ECCE, with the difference most marked in the first month after surgery.     

兔晶状体摘除和人工晶状体植入术后房水细胞因子水平和一氧化氮含量与眼内炎性反应的关系

目的：探讨晶状体摘除和人工晶状体植入术后房水中白细胞介素（interleukin,IL）-2、肿瘤坏死因子（tumour necrosis factor,TNF）-α水平及一氧化氮（nitric oxide,NO）含量与眼内炎性反应严重程度之间的关系。方法：将18只新西兰白兔随机分成3组,每组6只兔。Ⅰ组为正常对照组,Ⅱ组行囊外晶状体摘除术,Ⅲ组行囊外晶状体摘除及人工晶状体囊袋内植入术。分别于术后0、1、3、7、14及30d检查各组动物角膜水肿及前房渗出情况,抽取房水做房水细胞计数及分类,同时测定房水中细胞因子IL-2和TNF-α水平及NO2^-/NO3^-含量,并观察其变化。结果：Ⅲ组术后7-14d,前房渗出程度最严重,房水中单核/巨噬细胞数目最多。术后1-14dⅢ组房水中IL-2、TNF-α和NO2^-/NO3^-含量均明显高于Ⅰ、Ⅱ组,并于术后3-7d达高峰,2周后逐渐降低。各组房水IL-2、TNF-α、NO2^-/NO3^-含量和眼内炎性反应的严重程度变化规律基本一致,即炎性反应重时含量高。结论：人工晶状体植入术后眼内炎性反应的严重程度与房水细胞因子IL-2和TNF-α水平及NO含量变化有密切关系。     

Does surgical technique influence cataract surgery contamination?

PURPOSE: To compare cataract surgery contamination rates in large-incision extracapsular cataract extraction (ECCE) and phacoemulsification (PE), we studied 65 cases prospectively. METHODS: Thirty-five cases were operated by large-incision ECCE (Group I) and 30 by PE (Group II). Conjunctival swab cultures were taken immediately before surgery and anterior chamber aspirate was taken for culture upon completion of surgery for each case. RESULTS: Anterior chamber cultures were positive in 22.8% of the cases in group I and 23% in Group II. Frequencies of contamination in each group were no different (x2: 0.22, p>0.05). When the contaminations were evaluated in relation to operating time, prolongation of the operating time raised the contamination rate in Group I (p<0.05) but not in Group II (p>0.05). Silicone and PMMA intraocular lenses (IOL) were tested to see whether they had any additional risk of contamination. The frequencies of contaminated silicone IOL implanted cases (6/26) and contaminated PMMA IOL implanted cases (8/39) were similar (x2: 0.36, p>0. 05). CONCLUSIONS: Although the architecture of the incision and irrigation dynamics provided an advantage to the PE technique as the operating time became longer, routine PE was not superior to classical ECCE with respect to contamination when performed in the same circumstances. Prolonging the operating time raised the contamination rate in classical ECCE.     

Evaluation of bacterial contamination rate of the anterior chamber during phacoemulsification surgery using an automated microbial detection system

AIM:To assess the incidence of anterior chamber bacterial contamination during phacoemulsification surgery using an automated microbial detection system (BacT/Alert).METHODS:Sixty-nine eyes of 60 patients who had uneventful phacoemulsification surgery, enrolled in this prospective study. No prophylactic topical or systemic antibiotics were used before surgery. After antisepsis with povidone-iodine, two intraoperative anterior chamber aqueous samples were obtained, the first whilst entering anterior chamber, and the second at the end of surgery. BacT/Alert culture system was used to detect bacterial contamination in the aqueous samples.RESULTS: Neither aqueous samples obtained at the beginning nor conclusion of the surgery was positive for microorganisms on BacT/Alert culture system. The rate of bacterial contamination during surgery was 0%. None of the eyes developed acute-onset endophthalmitis after surgery.CONCLUSION:In this study, no bacterial contamination of anterior chamber was observed during cataract surgery. This result shows that meticulous surgical preparation and technique can prevent anterior chamber contamination during phacoemulsification cataract surgery.     

超声乳化吸出先天性白内障

目的:观察超声乳化在先天性白内障的应用。方法:对32例49眼行先天性白内障超声乳化吸出及人工晶状体植入,术中应用隧道切口和连续环形撕囊技术,低能量超声乳化或I/A系统清除晶状体核和皮质,囊袋内植入折叠式人工晶状体。并与同期相同条件的病例行ECCE PMMA人工晶状体植入术41例59眼相对比,观察术后视力及并发症。结果:术后1a时2组病例脱残率和并发症发生率有显著差异(P<0.01),其中后发性白内障发生率,超声乳化组6%,对照组76%。结论:本组病例中超声乳化吸出先天性白内障,有良好的前房稳定性,彻底清除晶状体皮质,术后并发症少。     

Ultrasound biomicroscopy examination of intraocular lens haptic position after phacoemulsification with continuous curvilinear capsulorhexis and extracapsular cataract extraction with linear capsulotomy.

PURPOSE: Intraocular lens (IOL) haptic position in 35 eyes that had undergone cataract surgery was examined with ultrasound biomicroscopy (UBM). METHODS: In a prospective randomized study the patients were operated by phacoemulsification using continuous curvilinear capsulorhexis (CCC) (group I) or by extracapsular cataract extraction (ECCE) using linear capsulotomy (group II). Ultrasound biomicroscopy was used to localize both haptics of the implanted intraocular lenses and to measure anterior chamber depth (ACD), iris thickness and anterior chamber angle. The inflammatory reaction in the anterior chamber was assessed with laser flare photometry. Slit lamp examination was performed. RESULTS: Both IOL haptics were found in the lens capsule in all 18 eyes in group I. In group II one of the haptics was located out of the capsule in 7 of 17 eyes (41%). The difference is statistically significant (p=0.01). Postoperatively mean ACD measured with the UBM was 4.06+/-0.30 mm in group I and 3.64+/-0.24 mm in group II (p=0.00025). CONCLUSION: The UBM examinations indicate that phacoemulsification with continuous curvilinear capsulorhexis is a more reliable technique than ECCE with linear capsulotomy to achieve implantation of the intraocular lens haptics in the capsular bag.