The role of intraocular lenses in anterior chamber contamination during cataract surgery

Post photorefractive keratectomy (PRK) infectious keratitis; six-year experience of a tertiary eye hospital

BACKGROUND/OBJECTIVES

As an essential development in the new century, surface ablation procedures have attracted increasing attention. There exists a concern regarding the risk of infectious keratitis. Hence, we aimed to investigate the rate and predisposing factors of infectious keratitis after photorefractive keratectomy (PRK).

SUBJECTS/METHODS

This retrospective study was designed in two phases. First, the rate of post-PRK keratitis of Farabi Eye Hospital was investigated. In other words, the targeted population was the patients who developed keratitis after performing procedure at Farabi Eye Hospital. In the second phase, all the patients with the diagnosis of post-PRK keratitis were studied regardless of the centre where surgery was performed. Patients with the diagnosis of infectious keratitis between 2014 and 2020 were enrolled and following information was analyzed: demographics, presentation time after surgery, perioperative medications, culture results, risk factors, medical treatment, complications, and final visual acuity.

RESULTS

The total number of PRK procedures in our centre was 24,986 (13,253 patients), in which 6 eyes of 5 patients developed keratitis. Beside these 5 patients, 24 referred patients (24 eyes) from the other centres were enrolled. Finally, a total number of 29 patients (30 eyes) were included. Our analysis revealed that manipulation of contact lens, dry eye, and blepharitis were the essential predisposing factors for keratitis development.

CONCLUSION

The overall post-PRK keratitis occurrence rate of our study was 0.02%. Our observation highlighted the importance of preoperative examination and treatment of the lids and dry eye disease.

The Prevalence of Infectious Keratitis after Keratorefractive Surgery: A Systematic Review and Meta-Analysis Study

BACKGROUND

The keratorefractive surgeries (KRS) are one of the most common ocular surgeries. One of the dangerous complications of these surgeries is infectious keratitis (IK), which is the second cause of blindness after cataract surgery. The purpose of this study was to estimate the prevalence of IK after KRS in different parts of the world.

METHODS

In order to obtain relevant studies, all national and international databases including IranMedex, SID, Magiran, IranDoc, Medlib, ScienceDirect, PubMed, Scopus, Cochrane, Embase, Web of Science, and Google Scholar were searched using standard keywords.

RESULTS

IK prevalence after KRS was 0.000496% (0.000145% for the left eye and 0.000149% for the right eye). IK prevalence after KRS in the United States, Europe, and Asia was 0.000667%, 0.000473%, and 0.000045%, respectively, in all of which the common microorganisms were Staphylococci. Meta-regression showed no significant association between IK after KRS and either sample size or publication year of the studies. IK prevalence after KRS in the right eye was more than that in the left one. Also, the probability of IK incidence after LASIK surgery was more than PRK and LASEK. In the evaluation of continents, IK after KRS in the United States was more frequent compared with Europe and Asia.

CONCLUSIONS

This study provided data as to the overall prevalence of IK following KRS and its variations according to the types of eye, surgery, pathogenic microorganism, and geographical location.

Risk factors for endophthalmitis following cataract surgery-our experience at a tertiary eye care centre in India

AIM

To determine the risk factors for acute endophthalmitis after cataract extraction in a tertiary care centre in India.

METHODS

We performed a nested case control study within a retrospective cohort. The surgical records of all patients with clinically diagnosed endophthalmitis within one month after cataract surgery, performed between January 2006 and December 2009, were reviewed. These were compared with randomly selected age and gender-matched controls, from patients having routine cataract surgery within ±1wk of the endophthalmitis case. Univariable and multivariable analysis were performed to identify risk factors for endophthalmitis.

RESULTS

Of the total 33 856 cataract surgeries performed during this period, there were 57 cases of postoperative acute endophthalmitis that met our study criteria. Thus, the overall incidence of endophthalmitis in our cohort was 1.6 per 1000 cataract extractions performed. Mean age of cases was 55.9y (SD: 10.9y) and for controls was 55.6y (SD: 9.8y). Thirty-five cases (61.4%) and 133 controls (59.6%) were males. Median time of onset of endophthalmitis was 4d (IQR 2-9d; range: 1-30d). Thirty-nine cases (68.4%) presented within 7d and 27 cases (47.4%) were culture positive. Two hundred and twenty-three age and gender matched controls were selected. In multivariate analysis, endophthalmitis was associated with posterior capsular rupture (PCR) during surgery (OR 6.98, 95%CI: 2.22-21.98), phacoemulsification via scleral incision with a foldable intraocular lens (IOL) implantation (OR 3.02, 95%CI: 1.13-8.04) and ocular co-morbidity (OR 2.32, 95%CI: 1.11-4.87).

CONCLUSION

PCR, presence of ocular co-morbidity, and phacoemulsification via scleral incision with foldable-IOL were found to be independent risk factors for acute endophthalmitis.

An 8-year retrospective study of cataract surgery and postoperative endophthalmitis: injectable intraocular lenses may reduce the incidence of postoperative endophthalmitis

BACKGROUND/AIMS

Postoperative endophthalmitis (POE) is a rare but potentially devastating complication of modern cataract surgery. We examine whether the use of injectable intraocular lenses (IOLs) is associated with a lower rate of POE after cataract surgery compared with forceps-inserted foldable IOLs.

METHODS

A single-centre retrospective cohort study of 25 410 cataract operations was performed over an 8-year period when standard practice in cataract surgery changed from the use of forceps-inserted foldable IOLs to injectable IOLs. Cases of POE were identified and the rates compared between the two groups.

RESULTS

Twelve cases of POE were identified in the study period. The rate of POE was significantly lower in the injectable IOL group compared with the forceps-inserted foldable IOL group (0.008% vs 0.081%, p=0.008). This difference remained significant when controlling for posterior capsular rupture and lens material.

CONCLUSIONS

This study, the largest of its kind to date, supports the use of injectable IOLs over forceps-inserted foldable IOLs as a significant measure in reducing the risk of POE.

Infectious keratitis in 18,651 laser surface ablation procedures

PURPOSE

To evaluate the incidence, culture results, risk factors, treatment strategies, and visual outcomes of infectious keratitis after surface ablation.

SETTING

Multicenter study in Spain.

DESIGN

Case series.

METHODS

The medical records of patients who had surface ablation between January 2003 and December 2009 were reviewed to identify cases of infectious keratitis. The incidence, risk factors, clinical course, days to diagnosis, medical and surgical treatment, and visual outcome were recorded. Main outcome measures were incidence of infectious keratitis after surface ablation, culture results, response to treatment, and visual outcomes.

RESULTS

The study reviewed the records of 9794 patients (18,651 eyes). Infectious keratitis after surface ablation was diagnosed in 39 eyes of 38 patients. The onset of infection was early (within 7 days after surgery) in 28 cases (71.79%). Cultures were positive in 13 of 27 cases in which samples were taken. The most frequently isolated microorganism was Staphylococcus species (9 cases). The final corrected distance visual acuity (CDVA) was 20/20 or better in 23 cases (58.97%), 20/40 or better in 36 cases (92.30%), and worse than 20/40 in 3 cases (7.69%).

CONCLUSIONS

The incidence of infectious keratitis after surface ablation was 0.20%. Infectious keratitis is a potentially vision-threatening complication. Prompt and aggressive management with an intensive regimen of fortified antibiotic agents is strongly recommended. Proper management can preserve useful vision in most cases.

FINANCIAL DISCLOSURE

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

Infectious keratitis in 204 586 LASIK procedures

PURPOSE

To investigate the incidence, culture results, risk factors, and visual outcomes of infectious keratitis after LASIK, and examine treatment strategies.

DESIGN

Retrospective study.

PARTICIPANTS

We included 107 613 patients who underwent LASIK at Clínica Baviera (Instituto Oftalmológico Europeo, Spain) from September 2002 to May 2008.

METHODS

The medical records of post-LASIK patients (204 586 eyes) were reviewed to identify cases of infectious keratitis. Incidence, risk factors, clinical course, days to diagnosis, medical and surgical treatment, and final visual outcomes were recorded.

MAIN OUTCOME MEASURES

Incidence of post-LASIK infectious keratitis, culture results, response to treatment, and visual outcome.

RESULTS

Post-LASIK infectious keratitis was diagnosed in 72 eyes from 63 patients. Onset of infection was early (within 7 days after surgery) in 62.5% of cases. Cultures were positive in 21 of 54 cases in which samples were taken. The most frequently isolated microorganism was Staphylococcus epidermidis (9 cases). Immediate flap lifting and irrigation with antibiotics was performed in 54 eyes; late flap lifting was subsequently required in 10 out of 18 cases initially treated with topical antibiotics alone. One case required flap amputation owing to flap necrosis. Final best spectacle-corrected visual acuity (BSCVA) was >or=20/20 in 38 cases (52.7%) and >or=20/40 in 67 cases (93.05%); final BSCVA was <20/40 in 5 cases (6.94%).

CONCLUSIONS

The incidence of post-LASIK infectious keratitis was 0.035% per procedure. Infectious keratitis after LASIK is a potentially vision-threatening complication. The appearance of infections in asymptomatic patients highlights the need for a proper schedule of follow-up appointments. Prompt and aggressive management of this LASIK complication with early flap lifting, scraping, culture, and irrigation with antibiotics is strongly recommended. Proper management can result in preserving useful vision.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Corneal interface contamination during laser in situ keratomileusis

PURPOSE

To measure the rate of corneal interface contamination during laser in situ keratomileusis (LASIK), determine probable sources of the contamination, and evaluate how the cornea reacts to the contamination.

SETTING

Department of Ophthalmology, Baqyatallah Hospital, Baqyatallah University, Tehran, Iran.

METHODS

In this case series, 200 eyes were evaluated for the corneal interface contamination at the end of LASIK. Cultures were taken from the upper and lower eyelid margins and the inferior fornices before surgery and from the corneal interface and the instrument at the end of surgery. Media were cultured at 37 degrees C for 14 days under aerobic and anaerobic conditions. Bacteria from positive cultures were isolated and identified by biochemical procedures to determine the species of the organisms.

RESULTS

The rate of contamination was 24.5%. The most common retrieved organism was Staphylococcus epidermidis (43 cases, 87.7%). None of the contaminated or noncontaminated cases developed corneal ulcers; however, 2 eyes developed diffuse lamellar keratitis.

CONCLUSION

The corneal stroma has the ability to clear introduced microorganisms during LASIK.

MINIMIZING THE RISK OF ENDOPHTHALMITIS FOLLOWING INTRAVITREOUS INJECTIONS

PURPOSE

To review techniques that are important in preventing endophthalmitis following intravitreous injections based on the available evidence.

METHODS

A review of the literature regarding existing evidence that is relevant to post-injection endophthalmitis prophylaxis.

RESULTS

The available evidence regarding endophthalmitis prophylaxis is largely based on intraocular surgery, particularly cataract surgery. Despite the controversy and the paucity of evidence regarding endophthalmitis prophylaxis for intravitreous injections, it is recommended that povidone-iodine should be used prior to intravitreous injections to minimize or eliminate the presence of ocular surface bacteria. Administration of topical antibiotics may also be considered before and after the intravitreous injections. Strict adherence to aseptic techniques, including the use of an eyelide speculum is also important.

CONCLUSION

Endophthalmitic can occur following intravitreous injections. Prophylaxis with topical povidone-iodine, and possibly antibiotics, as well as adherence to aseptic technique may minimize the risk of post-injection endophthalmitis.

A model for the management of an atypical endophthalmitis outbreak

PURPOSE OF STUDY

To present a model for the assessment, investigation, and management of an atypical outbreak of infectious endophthalmitis of indeterminate aetiology.

METHODS

A published statistical model was used to determine when the case-load constituted an outbreak. Intraocular surgery was discontinued and a multidisciplinary infection control team was formed aimed at identifying potential causative factors among the following categories: environment around theatre, preoperative preparation, intraoperative theatre practices, intraoperative surgical practices, postoperative practices, equipment maintenance guidelines, cleaning/sterilization practices, and microbiological screening.

RESULTS

Five cases of postoperative endophthalmitis developed following uncomplicated phacoemulsification cataract surgery by different surgeons over a 7-month period. Despite full investigation no single focus of infection could be determined. Four out of five cases were culture positive. Three grew Streptococcus viridans of different strains. The fourth culture grew Staphylococcus aureus. In the absence of a single causative factor, it was postulated the combined effect of multiple potential factors may have led to an increased bacterial load and subsequent infection rate. Improved practices were initiated including new cleaning protocols to combat the build-up of debris on phacoemulsification instruments. Cataract surgery was resumed with 3-monthly microbiological monitoring. There have been no further cases in the 12 months following the changes.

CONCLUSION

Outbreaks of endophthalmitis typically present over a short time period and could often be attributed to a single infective cause. We present our experience of detecting and managing this cluster and recommend a 'ground-up' multidisciplinary model to manage future outbreaks of this devastating condition.

Anterior chamber irrigation with an ozonated solution as prophylaxis against infectious endophthalmitis

PURPOSE

To assess the validity of anterior chamber irrigation with an ozonated solution as prophylaxis against endophthalmitis.

SETTING

Department of Ophthalmology, Nippon Medical School, Tokyo, Japan.

METHODS

Viability of human corneal endothelium in culture was assessed by the WST-8 assay, lactate dehydrogenase (LDH) release assay, and trypan blue exclusion assay after exposure to a 4 to 40 parts per million (ppm) solution for 10 to 60 seconds. The in vivo effect was observed 1 week after irrigation of a 4 ppm solution in the rabbit anterior chamber by trypan blue exclusion assay. Bactericidal efficacy of the anterior chamber irrigation with the 4 ppm solution was examined by bacterial colony count of the aqueous humor following methicillin-resistant Staphylococcus aureus (MRSA) contaminated intraocular lens implantation in the porcine eye.

RESULTS

The WST-8 assay revealed no significant reduction of viability with 10-second exposure to a 4 ppm solution. Lactate dehydrogenase release and trypan blue exclusion assays similarly demonstrated little damage after 60-second exposure to a 4 ppm solution. In the rabbit cornea 1 week after treatment, damage caused by 30-second exposure to a 4 ppm solution was not significant. The MRSA colony count documented almost complete bactericidal action with 5-second exposure to the 4 ppm solution when no ophthalmic viscosurgical device existed in the anterior chamber.

CONCLUSION

Limited damage to the corneal endothelium after 10-second exposure and potent bactericidal action with 5-second exposure suggests the validity of anterior chamber irrigation with a 4 ppm ozonated solution as prophylaxis against endophthalmitis.

Three-day application of topical ofloxacin reduces the contamination rate of microsurgical knives in cataract surgery

PURPOSE

To determine the rate of contamination of microsurgical knives during cataract surgery and the benefit of a 3-day versus a 1-hour preoperative application of topical ofloxacin in reducing the contamination rate.

DESIGN

Prospective, randomized controlled trial.

PARTICIPANTS

Seventy-eight eyes of 75 patients were randomly assigned to control (39 eyes) or study groups (39 eyes).

METHODS

All patients from both groups received 0.3% topical ofloxacin 1 hour before surgery, 5% povidone-iodine (PVI) scrub of the periorbital area, and 2 drops of PVI onto the ocular surface preoperatively. The patients in the study group also received ofloxacin 4 times a day for 3 days before surgery.

MAIN OUTCOME MEASURES

Microsurgical knives were placed in blood culture broth media immediately after the incision had been made. The number of positive cultures and types of bacteria isolated were determined.

RESULTS

Ten of 39 knives (26%) in the control group were found to be positive for bacterial growth compared with only 2 of 39 (5%) in the study group (P = 0.028).

CONCLUSIONS

The initial paracentesis incision frequently results in contamination of the microsurgical knife and may serve as a mechanism for introducing bacteria from the ocular surface into the anterior chamber. The application of topical ofloxacin for 3 days before surgery significantly reduces the contamination rate of the microsurgical knives, compared with a preoperative application of ofloxacin given 1 hour before surgery.

The challenge of determining aqueous contamination rate in anterior segment intraocular surgery

PURPOSE

To determine aqueous contamination rate in anterior segment intraocular surgery using two different techniques of obtaining aqueous fluid and to assess whether a 3-day application of topical 0.3% ofloxacin reduces this contamination rate compared with a 1-hour application.

DESIGN

Randomized clinical trial.

METHODS

One hundred and thirty-three eyes of 130 patients undergoing anterior segment intraocular surgery were randomized to either control (64 eyes received topical ofloxacin 1 hour before surgery) or study groups (69 eyes received topical ofloxacin four times a day for 3 days before surgery in addition to 1 hour preoperatively). Eyes in both groups received a periorbital iodine scrub and two drops of topical 5% iodine. Aqueous fluid was obtained at the beginning and conclusion of surgery using a cannula passed through a paracentesis or a needle passed through clear cornea. The aqueous, cannula, and needles were inoculated in blood culture media broth and bacterial growth was identified.

RESULTS

Overall, eight of 89 aqueous samples (9%) obtained using a cannula at the beginning of surgery were culture-positive. Similarly, six of 41 aqueous samples (15%) obtained through a needle through clear cornea at the beginning of surgery showed contamination. At the conclusion of surgery, nine of 112 samples (8%) showed positive cultures. There was no difference in the aqueous contamination rates between the control and study groups.

CONCLUSIONS

Despite the use of a needle to obtain aqueous fluid at the beginning of surgery before creating a paracentesis, the aqueous contamination rate remained higher than that found at the conclusion of surgery. A 3-day application of topical ofloxacin before surgery did not reduce the anterior chamber aqueous contamination rate relative to a 1-hour application.

A 10 year retrospective survey of cataract surgery and endophthalmitis in a single eye unit: injectable lenses lower the incidence of endophthalmitis

AIM

To study the incidence of endophthalmitis following cataract surgery over a 10 year period, and to examine ways in which this may be related to changes in surgical technique.

METHODS

All cases of endophthalmitis occurring over a 10 year period within a single ophthalmic unit in the United Kingdom were reviewed, and possible risk factors identified.

RESULTS

During the study period, as the technique of extracapsular cataract surgery was replaced by phacoemulsification, there was a commensurate reduction in the incidence of endophthalmitis. Injectable IOLs were associated with the lowest risk of postoperative endophthalmitis (0.028%).

CONCLUSIONS

Injectable intraocular lenses do not make contact with the ocular surface and this may result in the observed lower rate of endophthalmitis. This, and the ease with which they can be inserted through small incisions, support their use as the first line method of lens insertion.

Topical anaesthesia: a risk factor for post-cataract-extraction endophthalmitis?

PURPOSE

To investigate if the incidence of postoperative endophthalmitis in temporal clear corneal cataract surgery is influenced by the use of topical anaesthesia compared to retrobulbar anaesthesia.

METHODS

A retrospective study was conducted of one surgeon's cataract surgery between October 1997 and October 2001.

RESULTS

Between October 1997 and May 2000, there were 633 cataract extractions performed with 219 patients operated under topical anaesthesia and 414 under retro-bulbar injection. The selection criteria were that surgically easier cases underwent topical anaesthesia. There were five patients who suffered postoperative endophthalmitis in their first week, of which four cases were under topical anaesthesia. This was shown to be borderline significance of P = 0.05 using the Fischer exact 2-tailed test. There was a complicated case, operated under retrobulbar anaesthesia, who had a low-grade endophthalmitis in the second postoperative week. The four topical cases and the case from the second week all grew Staphylococcus epidermidis. The retrobulbar case developing endophthalmitis in the first week grew alpha haemolytic Streptococcus. After May 2000, there was a change to performing all cataract surgery under retrobulbar anaesthesia and the next 453 cases had no incidence of endophthalmitis.

CONCLUSION

Topical anaesthesia techniques in temporal clear corneal cataract extraction may be a factor in endophthalmitis.

Bacterial adhesion to rigid and foldable posterior chamber intraocular lenses: in vitro study

PURPOSE

To determine the in vitro bacterial adherence to intraocular lenses (IOLs) routinely used at 1 center.

SETTING

University Hospital of Vienna, Vienna, Austria.

METHODS

Four types of rigid IOLs (hydrophobic poly[methyl methacrylate] [PMMA] and hydrophilic heparin-surface-modified PMMA) and 5 types of foldable intraocular lenses (hydrophobic silicone, hydrophobic acrylic, and hydrophilic acrylic) were used in the experiment. Under standardized conditions, the IOLs were contaminated with 2 strains of Staphylococcus epidermidis. A sonication method and impression method were used for quantification. The mean bacterial density per lens type (colony forming units/mm(2)) was compared.

RESULTS

With both germs and both quantification methods, more bacteria was found on hydrophobic lenses than on IOLs with hydrophilic surfaces (P =.001). The Alcon AcrySof and Askin UV80F IOLs had the greatest and the Corneal Acrygel and Bausch & Lomb Hydroview IOLs the least affinity to these microorganisms.

CONCLUSION

The data suggest that hydrophilic IOLs can help reduce the rate of postoperative endophthalmitis as a result of their surface properties.

Single-action implantation of a 3-piece acrylic intraocular lens with an injector

We report a method to insert a 3-piece AcrySof MA30BA acrylic foldable intraocular lens (IOL) (Alcon) in a single action using a Monarch II (Alcon) injector. The technique was used in 134 eyes. The incision widths ranged from 3.00 to 3.75 mm. The IOLs were successfully inserted in the capsular bag. Complications included cracks in the IOL optic in 3 eyes (3%), haptic damage in 3 eyes (3%), and inadequate self-sealing of the incision in 18 eyes (13%).