Effect of operative field irrigation on intraoperative bacterial contamination and postoperative endophthalmitis rates in 25-gauge vitrectomy

Evaluation of the Possible Influence of Povidone Iodine (PVI) Solution and Polyhexanide (PHMB) on Wound Healing in Corneal Epithelial Regeneration

This study investigates the possible toxic effects of the preoperative antiseptic substances povidone iodine (PVI) and polyhexanide (PHMB; Serasept® 2) on wound healing in ophthalmology. To assess this impact, human telomerase-immortalized corneal epithelial (hTCEpi) cells and human telomerase-immortalized conjunctival epithelial (hCjE) cells were exposed to 1% and 5% PVI or 0.04% PHMB for different periods to evaluate the cytotoxicity of these two antiseptics. Furthermore, the toxicity of these antiseptics was investigated in a human tissue-specific corneal epithelial construct and porcine eye culture model. The results reveal the high cytotoxicity of PVI and PHMB in the hTCEpi and hCjE in monolayer cell culture models, independent of the incubation time and concentration of these substances. However, after hTCEpi cell differentiation into a tissue-specific corneal epithelial construct, contact with these antiseptics for the relevant preoperative time did not alter cPARP1 or Ki67 expression. Furthermore, the wound-healing process in the porcine cornea was not significantly influenced after incubation with these antiseptics. In summary, corneal and conjunctival epithelial cell lines are very sensitive to PVI and PHMB, whereas no significant alterations were found in intact tissue-specific corneal epithelial constructs or porcine corneas. Therefore, we could not identify PVI and PHMB as reasons for postoperative eye irritation.

Doctor I Have an Iodine Allergy

Ophthalmologists frequently face patients who refuse asepsis protocols involving povidone-iodine (PI) due to claims of an allergy to iodine. Such patients usually base this claim on previous reactions to shellfish consumption or to imaging procedures that used iodine-based contrast agents. Allergy to iodine, however, is biologically impossible, and iodine deficiency causes severe developmental problems, including mental retardation. Furthermore, shellfish allergy is due to tropomyosins in muscle tissue, and reactions to intravascular contrast dyes are due to hyperosmolar solutions; neither “allergy” is due to iodine. PI, which contains 9–12% iodine, is the preferred antiseptic for ophthalmic procedures. Experience shows that PI can be administered safely to patients claiming iodine allergy. True allergy to PI is rare and, if indicated, skin patch testing can be performed prior to surgery. Patients who react adversely to highly concentrated (5–10%) PI usually experience toxicity to the corneal and conjunctival epithelium after topical administration. Dilute (0.1–0.25%) PI kills microbes quicker than higher concentrations but for shorter periods of time because the total dose of iodine is smaller. Repeated administration (every 20–30 s) of dilute PI effectively kills microbes for as long as necessary with little risk of epithelial toxicity.

Comparative Evaluation of Bandage Contact Lenses and Eye Patching after Bilateral Cataract Surgery

Purpose

To comparatively evaluate the safety and satisfaction of bandage contact lens (BCL) and eye patching in patients after cataract surgery.

Methods

Sixteen (32 eyes) patients who planned to undergo bilateral cataract surgery were recruited. The two eyes of each patient were randomly divided into 2 groups. Group A and Group B were instructed to wear BCLs immediately at the end of the surgery until one week and eye patch immediately after surgery until one day, respectively. Visual analog scales of ten specific symptoms, Visual Function Index (VF-14) questionnaire, and best-corrected visual acuity (BCVA) were conducted on the first day before the surgery and Day 1 and Day 7 after surgery. Oculus keratography was conducted on the first day before surgery and on Day 7. Patient satisfaction was determined on Day 1. Moreover, bacterial species in the conjunctival sac, meibomian gland secretions, and BCLs were subsequently identified using 16S rRNA gene sequencing.

Results

The patient satisfaction scores of Group A were higher than Group B. Group A were more motivated to choose the same treatment and were more likely to recommend BCLs to others. No statistically significant differences were found in bacterial culture positivity between the groups. The differences in ocular signs and symptoms between the two groups were not statistically significant. There were no significant differences in the BCVA and VF-14 between the groups at any time point.

Conclusions

BCLs could be safely and effectively used in patients after cataract surgery.

INCIDENCE OF ENDOPHTHALMITIS AFTER VITRECTOMY: A Systematic Review and Meta-analysis

PURPOSE

The purpose of this study was to review the literature reporting rates of postoperative endophthalmitis after pars plana vitrectomy and investigate whether modern microincision vitrectomy surgery (MIVS) increases the postoperative endophthalmitis rate, compared with traditional 20-gauge (20 G) vitrectomy.

METHODS

A comprehensive literature search was performed to identify studies describing the incidence of post-pars plana vitrectomy endophthalmitis. A meta-analysis of comparative studies reporting the endophthalmitis rates after MIVS versus 20 G vitrectomy was also conducted.

RESULTS

A total of 31 studies reported 199 endophthalmitis cases in 363,544 participants (0.05%). The incidence of endophthalmitis after 20 G vitrectomy was 0.04% (88/229,435), compared with 0.03% (8/27,326) after 23 G and 0.11% (33/29,676) after 25 G. The meta-analysis demonstrated that the incidence of endophthalmitis was higher after MIVS (23 G/25 G) compared with 20 G vitrectomy (odds ratio = 3.39, 95% confidence interval, 1.39-8.23). In a subgroup analysis, we also found an increased risk of endophthalmitis after 25 G compared with 20 G vitrectomy (odds ratio = 4.09, 95% confidence interval, 2.33-7.18), but not for 23 G versus 20 G (odds ratio = 1.14, 95% confidence interval, 0.47-2.78).

CONCLUSION

The incidence of post-pars plana vitrectomy endophthalmitis was low, with no significant differences between 23 G MIVS and 20 G vitrectomy, but 25 G MIVS may result in a higher postoperative endophthalmitis rate.

The Effectiveness of 0.6% Povidone Iodine Eye Drops in Reducing the Conjunctival Bacterial Load and Needle Contamination in Patients Undergoing Anti-VEGF Intravitreal Injection: A Prospective, Randomized Study

The study purpose was to assess the efficacy of a preservative-free 0.6% povidone iodine eye drops as perioperative prophylactic treatment for reducing conjunctival bacterial load and the rate of needle contamination in patients undergoing intravitreal anti-vascular endothelial growth factor injection. Enrolled patients were randomized to either the study group (0.6% povidone iodine, three day-prophylactic treatment before the injection) or to the control group (placebo, three day-prophylactic treatment). Conjunctival swabs were obtained before and after the prophylactic treatment in both groups. Intravitreal injections were performed in a sterile fashion. The injection needle and a control needle were collected for microbiological culture. Data from 254 and 253 eyes in the study group and control group, respectively, were analyzed. Bacterial growth from conjunctival swab cultures was significantly lower after 0.6% povidone iodine prophylaxis compared to baseline and to placebo prophylaxis (p < 0.001), showing an 82% eradication rate in the study group. No injection needle showed bacterial contamination in the study group, whereas six needles were culture-positive in the control group (p = 0.015). No serious ocular and non-ocular adverse events were recorded. The 0.6% povidone iodine solution proved an effective treatment in reducing conjunctival bacterial load and risk of needle contamination.

Intravitreal Injection of 1.25% Povidone Iodine Followed by Vitrectomy Using 0.025% Povidone Iodine Irrigation for Treating Endophthalmitis

Purpose

To investigate the safety and effectiveness of intravitreal injection (IVI) of 1.25% povidone iodine (PI) followed by vitrectomy using 0.025% PI irrigation for treating endophthalmitis.

Methods

Prospective case series study. Nine eyes of 8 patients with postoperative or endogenous endophthalmitis treated at the Nihon University Hospital between April 2015 and October 2017 were studied. First, IVI of 0.1 mL/1.25%PI was conducted, followed by anterior chamber irrigation and vitrectomy using 0.025%PI irrigation solution. Corneal epithelial damage, anterior chamber inflammation, and vitreous inflammation were assessed and fundus examinations were performed, using a slit-lamp microscope and indirect ophthalmoscopy. A specular microscope, Goldmann perimetry, and electroretinography (ERG) were also used.

Results

In all but case 7, endophthalmitis resolved rapidly and good visual acuity was maintained. No adverse events were noted. Furthermore, the perioperative ERG showed improvements in the oscillatory potentials amplitudes on ERG and flicker ERG, as well as in the implicit time of the a-wave, suggesting functional recovery in the retinal outer and inner layers after therapy.

Conclusions

IVI of PI followed by vitrectomy was thought to be a safe and effective treatment for endophthalmitis.

Translational Relevance

We succeeded in proving the clinical safety of IVI of PI followed by vitrectomy with PI irrigation as well as previous experimental reports. PI is available in world widely, therefore this method will be optimal treatment for endophthalmitis.

Preoperative preparation of eye with chlorhexidine solution significantly reduces bacterial load prior to 23-gauge vitrectomy in Swedish health care

Background

Bacteria in the conjunctiva present a potential risk of vitreous cavity infection during 23-gauge pars plana vitrectomy (PPV). Current preoperative procedures used in Sweden include irrigation with chlorhexidine solution (CHX) 0.05% only and no iodine solutions. We evaluated the bacterial diversity and load before and after this single antibacterial measure.

Methods

In a prospective, consecutive cohort we investigated bacterial growth in samples from 40 eyes in 39 consecutive individuals subjected to vitrectomy. A conjunctival specimen was collected from each preoperative patient before and after irrigating of eye with CHX, 0.05% solution. Iodine was not used during any part of the surgery. One drop of chloramphenicol was administered prior to surgery. Samples from vitreous cavity were collected at the beginning and end of vitrectomy. All conjunctival specimens were cultured for different species and quantified using colony forming units (CFU).

Results

There was a significant 82% reduction in the total number of CFUs for all bacteria in all eyes (P < 0.0001), and 90% reduction for coagulase negative staphylococci (CoNS) alone (P = 0.0002). The number of eyes with positive bacterial growth in conjunctival samples decreased from 33 to 18 after irrigation with CHX (P = 0.0023). The most common bacteria prior to surgery were CoNS (70%), Propionibacterium acnes (55%) and Corynebacterium species (36%). No case of post-vitrectomy endophthalmitis was reported during mean follow-up time, which was 4.6 ± 2.3 (range; 1.5 to 9) months.

Conclusions

Patients undergoing PPV harbored bacteria in conjunctiva capable of causing post-vitrectomy endophthalmitis. Preoperative preparation with CHX significantly reduced the bacterial load in the conjunctival samples subsequently leading to very low inoculation rates in recovered vitreous samples. Thus, CHX used as a single disinfectant agent might be an effective preoperative procedure for eye surgery in Sweden. This is a relatively small study but the results could be a reference for other intraocular surgeries.

The use of povidone-iodine in ophthalmology

PURPOSE OF REVIEW

Povidone-iodine (PVI) is a disinfectant and antiseptic agent used for preoperative preparation of the skin and mucous membranes, as well as for the treatment of contaminated wounds. Currently regimens for prophylaxis against postsurgical endophthalmitis are being modified, including a total withdrawal of antibiotics in intravitreal injections. The aim of this study was to evaluate the use of PVI in ophthalmology.

RECENT FINDINGS

As a result of its broad spectrum of microbicidal activity, PVI is routinely used in ophthalmic surgery. However, various protocols are applied worldwide and within different procedures. Additional indications include prophylaxis against ophthalmia neonatorum, acute conjunctivitis, adenoviral conjunctivitis, bacterial keratitis or corneal ulcer, endophthalmitis, giant fornix syndrome, and antimicrobial prophylaxis in patients with Boston type I keratoprosthesis.

SUMMARY

Despite the introduction of new antiseptics in surgery, PVI is still the preeminent antiseptic measure in ophthalmology. Its use is economically reasonable. There have been no reports of resistance to PVI or anaphylaxis with topical ophthalmic use. Furthermore, it does not induce resistance or cross-grztance to antibiotics. With these advantages the range of indications for topical use of antibiotics might decrease, with PVI as the sole perioperative antiseptic measure. Additional studies are required to assess the optimal timing, concentration and exposure time within different ophthalmic procedures.

Evaluation of the vitreous microbial contamination rate in office-based three-port microincision vitrectomy surgery using Retrector technology

Background

To perform a microbiological contamination analysis of the vitreous during office-based micro-incision vitrectomy surgery (MIVS) assessing whether the bacteria detected correlated with patient's ocular conjunctival flora.

Methods

This is a prospective, interventional, nonrandomized case series of patients undergoing office-based MIVS, anti-VEGF, and dexamethasone intravitreal injections (triple therapy) for the treatment of wet age-related macular degeneration (AMD) and diabetic macular edema (DME).

All patients were operated at a small procedure room in an ambulatory clinic of the Department of Ophthalmology, University of Montreal, Quebec, Canada. Conjunctival samples were done before placing the sclerotomies. The MIVS was done with a 23-gauge retractable vitrector, a 27-gauge infusion line, and a 29-gauge chandelier. Undiluted and diluted vitreous were collected for aerobic, anaerobic and fungal cultures. Outcomes measured were bacterial species identification within samples collected from the conjunctiva and the vitreous.

Results

Thirty-seven patients (37 eyes) were recruited and completed over 17 months of follow-up. Twenty-eight had wet AMD and nine had DME. There were 13 men and 24 women, with a mean age of 78 years. Eighteen patients (46%) had culture positive conjunctival flora. Twenty-six bacterial colonies were tabulated in total from the conjunctival swabs. All bacteria detected were gram-positive bacteria (100%), most commonly: Staphylococcus epidermitis in 11 (42%) and Corynebacterium sp. in 6 (23%). Only 1/18 patients had more than 3 species isolated, 6/18 patients had 2 species and 11/18 patients had 1 species identified on the conjunctival swab. Only 1 of the 37 undiluted midvitreous samples was culture positive, equating to a contamination rate of 2.7%. None of the diluted vitreous samples were culture positive. All cultures were negative for fungus. No serious postoperative complications occurred, including bacterial endophthalmitis, choroidal detachment, and retinal detachment.

Conclusion

This preliminary study of office-based MIVS gives us insights on the ocular surface microbial profile and vitreous contamination rate of performing such procedures outside the OR-controlled environment. Our initial results seem to indicate that there is little risk of bacterial translocation and contamination from the conjunctiva into the vitreous. Therefore, if endophthalmitis occurs post-operatively, the source may likely arise after the procedure. Larger studies are needed to confirm our data.

Reduction of vitreous contamination rate after 25-gauge vitrectomy by surface irrigation with 0.25% povidone-iodine

PURPOSE

To examine whether repeated ocular surface irrigation with 0.25% povidone-iodine, which is highly bactericidal and nonoculotoxic, reduces bacterial contamination of the vitreous during 25-gauge vitrectomy.

METHODS

Overall, 4,407 eyes undergoing 25-gauge vitrectomy were studied; of these, 2,801 were irrigated with infusion fluid (group A) and 1,606 with 0.25% povidone-iodine (group B). In each group (A and B), 103 eyes were studied bacteriologically, using ocular surface fluid samples after placing lid speculum (S1), after operative field irrigation (S2), and in vitreous samples at the beginning (V1) and at the completion of vitrectomy (V2).

RESULTS

Bacterial contamination rate in S1 did not differ significantly between the groups A (5.5%) and B (6.8%). However, the contamination rates in S2, V1, and V2 were apparently lower in group B (0%, 0%, and 0%, respectively) than in group A (2.0%, 1.0%, and 2.0%, respectively). Incidence of endophthalmitis was 0 of 2,801 eyes in group A and 0 of 1,606 eyes in group B.

CONCLUSION

In 25-gauge vitrectomy, repeated operative field irrigation with 0.25% povidone-iodine reduced bacterial contamination in vitreous to extremely low level.

Four cases of endophthalmitis after 25-gauge pars plana vitrectomy

We report our recent experience with four cases of endophthalmitis (one male, three females) after 25-gauge pars plana vitrectomy (PPV). One was a case of persistent cystoid macular edema caused by branch retinal vein occlusion, whereas the remaining three were cases of epiretinal membrane. Preoperative antibiotics before the first PPV procedure were not administered in three of the four cases. Endophthalmitis occurred 2-4 days after the first procedure in all cases, for which ceftazidime 2.0 mg/0.1 mL and vancomycin 1.0 mg/0.1 mL were injected into the vitreous cavity. This was followed by emergent 20-gauge PPV and intraocular lens removal using an infusion fluid containing ceftazidime and vancomycin. After the second PPV procedure, progress was good in three cases while retinal detachment occurred in the remaining case one month after surgery; this case required a third PPV procedure. Final best-corrected visual acuity ranged from 20/100 to 20/25 for the four cases. Bacterial cultures were negative after the second PPV procedure in all cases. In conclusion, postoperative endophthalmitis occurred in four of 502 cases (0.80%) that underwent 25-gauge PPV at our hospital. It is important to minimize the incidence of endophthalmitis after 25-gauge PPV.

Reduction of anterior chamber contamination rate after cataract surgery by intraoperative surface irrigation with 0.25% povidone-iodine

PURPOSE

To prove the hypothesis that during cataract surgery, repeated irrigation of the operative field with povidone-iodine of 0.25% reduces the anterior chamber bacterial contamination rate at completion of operation.

DESIGN

Prospective, interventional case series.

METHODS

In 404 consecutive eyes, the operative field was irrigated with infusion fluid in 202 eyes (group A) and with 0.25% povidone-iodine in 202 eyes (group B). Bacteriologic culture was performed using the following samples: ocular surface fluid after lid speculum placement and anterior chamber fluid at the completion of surgery. Anterior chamber fluid samples were collected at the beginning and completion of surgery for iodide ion concentration measurement. Corneal endothelial cell density was measured using a specular microscope before surgery and on day 7 after surgery.

RESULTS

Bacterial detection rate in ocular surface fluid was not significantly different between group A (5.5%) and group B (6.0%), but the rate in anterior chamber fluid was significantly (P = .0017) reduced in group B (0%) compared with group A (5.0%). Iodide ion concentrations at the start and end of surgery were 7.5 ± 0.7 μg/mL and 3.5 ± 0.7 μg/mL, respectively, in group B and less than 0.1 μg/mL both at the start and end of surgery in group A. Corneal endothelial cell densities were not significantly difference between groups A and B before surgery (2614 ± 233/mm² vs 2534 ± 173/mm²; P = .2254) and 7 days after surgery (2463 ± 269/mm² vs 2338 ± 204/mm²; P = .4044).

CONCLUSIONS

In cataract surgery, repeated irrigation of the operative field with povidone-iodine at a concentration of 0.25% achieved an extremely low bacterial contamination rate in the anterior chamber at the completion of surgery.