Vitreous wick syndrome--a potential cause of endophthalmitis after intravitreal injection of triamcinolone through the pars plana

Feasibility demonstration of a device for vitreous liquid biopsy incidental to intravitreal injection

PURPOSE

VitreoDx is an experimental device enabling push-button collection of a neat vitreous liquid biopsy incidental to an intravitreal injection. We explored the ability of the device to collect a sample usable for proteomic biomarker discovery and testing.

DESIGN

Pilot study using ex vivo human eyes.

METHODS

Non-vitrectomized, human eyes from nine donors 75-91 years of age were refrigerated in BSS and used within 5 days of death. Four VitreoDx devices fitted with 25G needles, and four staked needle insulin syringes with 30G needles, were inserted at equal intervals through the pars plana of each eye and held in place by a fixture. The sampling mode of each VitreoDx device was triggered to attempt to acquire a liquid biopsy up to 70 μL. The plunger of each insulin syringe was retracted to attempt to obtain a liquid biopsy with a maximum volume of 50 μL. Samples acquired with the VitreoDx were extracted to polypropylene cryovials, refrigerated to -80 ºC, and sent for offsite proteomic analysis by proximity extension assay with a focus on panels containing approved and pipelined drug targets for neovascular disease and inflammatory factors.

RESULTS

Of the attempted liquid biopsies with the novel 25G VitreoDx, 92% (66 of 72) resulted in successful acquisition (>25 μL) while 89% (64 of 72) attempted by a traditional 30G needle resulted in a successful acquisition. Sample volume sufficient for proteomics array analysis was acquired by the VitreoDx for every eye. Detectable protein was found for 151 of 166 unique proteins assayed in at least 25% of eyes sampled by VitreoDx.

CONCLUSIONS

The high acquisition rate achieved by the prototype was similar to that achieved in previous clinical studies where a standard syringe was used with a 25G needle to biopsy vitreous fluid directly prior to standard intravitreal injection. Successful aspiration rates were likewise high for 30G needles. Together, these suggest that it is possible to routinely acquire liquid vitreous biopsies from patients who typically receive intravitreal injections with an injection device using a standard size needle without a vitreous cutter. Protein analysis shows that proteins of interest survive the sampling mechanism and may have potential to direct care in the future.

Self-sealing hyaluronic acid-coated 30-gauge intravitreal injection needles for preventing vitreous and drug reflux through needle passage

Self-sealing hyaluronic acid (HA)-coated self-sealing 30-gauge needles exhibiting instant leakage prevention of intravitreal humor and injected drug were developed in this study. Ninety New Zealand rabbits were used in this study. We assessed dye regurgitation in intravitreal ICG dye injections using HA-coated needles (HA needle group) and conventional needles (control group). Vitreous humor levels of anti-vascular endothelial growth factor (VEGF) were compared between groups one, three, and seven days after intravitreal bevacizumab (0.016 mL) injections. Expression levels of inflammatory cytokines in the aqueous humor and vitreous humor, including prostaglandin E₂ (PGE₂), interferon-γ, tumor necrosis factor-α, interleukin (IL)-1β, IL-4, IL-6, IL-17, and IL-8, were compared between HA needle, control, and normal (in which intravitreal injection was not performed) groups following 12 intravitreal injections over a period of one week. In the HA needle group, HA remained at the injection site and blocked the hole after intravitreal injection. Dye regurgitation occurred significantly less frequently in the HA needle group (16.7%) than the control group (55.6%) after intravitreal ICG dye injection. Meanwhile, vitreous anti-VEGF levels were markedly higher in the HA needle group than the control group one and three days after intravitreal bevacizumab injections. After 12 intravitreal injections, expression levels of aqueous and vitreous IL-8 significantly increased in the control group compared to the HA needle and normal groups. Conversely, there were no significant differences in the expression of the other seven cytokines among the three groups. Intravitreal injections using HA-coated self-sealing 30-gauge needles can block the outflow of vitreous humor and drugs through the needle passage.

[Postoperative endophthalmitis-a review of literature]

Postoperative endophthalmitis is one of the most feared complications for ophthalmologists, and the number of infections after intraocular procedures have been increasing. Nonetheless, a prompt intervention can result in the recovery of vision. In the past, endophthalmitis after cataract surgery was accountable for the majority of cases but is becoming less frequent due to the progress of surgical techniques and demographic developments with a steadily increasing number of intravitreal injections. In this article, the different forms of postoperative endophthalmitis are assessed in terms of pathophysiology and their specific characteristics depending on their etiology.

Acute Bacterial Tenonitis and Conjunctivitis following Intravitreal Injection

A 73-year-old man presented 3 days after intravitreal injection (IVI) with bevacizumab for treatment of neovascular age-related macular degeneration with pain and redness around the injection site. Examination showed conjunctival edema and injection around the injection site and a central infiltrate at the injection site consistent with infection of Tenon's capsule and the conjunctiva. Infection of a vitreous wick was considered, but vitreous inflammation was not present. Acute bacterial tenonitis and conjunctivitis were diagnosed, and the patient was prescribed topical antibiotic drops. The patient's symptoms were resolved within 48 h following the use of topical antibiotic drops, so a culture was not performed. The patient did not develop endophthalmitis. To our knowledge, this is the first reported case of acute bacterial tenonitis and conjunctivitis of the injection site following IVI. Even with the use of betadine, infection of Tenon's capsule and the conjunctiva may occur after IVI and must be differentiated from other causes of postinjection ocular redness such as chemical irritation of the ocular surface, corneal abrasions, and endophthalmitis.

Vitreous Reflux Frequency and Intraocular Pressure After First-Time Intravitreal Aflibercept Injections: Comparison of 30- and 32-Gauge Needles

Purpose

To compare the effects of 30-gauge versus 32-gauge needles on vitreous reflux (VR) frequency and intraocular pressure (IOP) following first-time intravitreal aflibercept injections.

Materials and Methods

Overall, 116 patients (116 eyes) who received intravitreal injections using 30-gauge needles and 104 patients (104 eyes) who received the same injection using 32-gauge needles were reviewed. The medical records of 116 patients who each received an intravitreal injection using a 30-gauge needle (median age: 67.5 ± 13.9 years) and 104 patients who each received the same injection using a 32-gauge needle (median age: 66. 3 ± 10.6 years) from January 2015 to June 2019 were compared.

Results

No significant difference in the frequency of VR was observed between patients injected using 30-gauge needles (38/116) and patients injected using 32-gauge needles (31/104, P = 0.64). There were no significant differences in the VR rates of patients with phakic and pseudophakic eyes between those injected using 30-gauge (P = 0.94) or 32-gauge needles (P = 0.77). Axial length did not significantly differ between patients with and without VR when injected using 30-gauge (P = 0.89) and with 32-gauge needles (P = 0.69). IOP immediately after injection was significantly higher in patients injected using 30-gauge needles than in patients injected using 32-gauge needles (P < 0.01).

Conclusion

VR frequency was not correlated with needle size, lens status, or axial length. Patients receiving injections using 30-gauge needles had higher IOP immediately after intravitreal injection.

Preoperative estimation of distance between retinal break and limbus with wide-field fundus imaging: Potential clinical utility for conventional scleral buckling

OBJECTIVE

Accurate scleral marking of retinal breaks is essential for successful scleral buckling. This study aimed to investigate the use of wide-field fundus images obtained with an Optos for preoperative estimation of the distance from the limbus to the retinal breaks.

METHODS AND ANALYSIS

This is a retrospective review of 29 eyes from 26 patients with rhegmatogenous retinal detachment who received scleral buckling with anatomically successful repair. They underwent wide-field fundus photography with Optos California. In the pre- and postoperative fundus images, we measured distances from the macula to the retinal tears (TM), to the center of the vortex veins (VM), to the optic disc (DM), and to the posterior edge of the scleral buckle (BM).

RESULTS

(BM-VM) / DM was significantly correlated with the distance from the limbus to the posterior edge of the scleral buckle that had been determined intraoperatively. (r = 0.705; p<0.001) We applied a regression line derived from this correlation with the value of (TM -VM) / DM in order to calculate estimated distances between retinal breaks and the limbus. The calculated distances were all within the range of distances from the limbus to the anterior and posterior edges of the scleral buckles.

CONCLUSION

Preoperative analysis of Optos images may be useful for estimating the distance from the limbus to retinal breaks, which might aid scleral marking during scleral buckling surgery.

Complications of Intravitreous Injections in Patients with Diabetes

Intravitreous injections are presently the second most frequently performed ophthalmic procedure and the most common vitreoretinal procedure. In diabetic patients, intravitreous injections are frequently performed for the treatment of center-involved diabetic macular edema, proliferative diabetic retinopathy, or other co-existing retinal vascular disease. Diabetic patients may be at higher risk of adverse events compared to non-diabetic individuals, given frequent systemic comorbidities, such as cardiovascular and renal disease and increased susceptibility to infection. This review highlights the potential complications and safety considerations in intravitreous injections in patients with diabetes.

Prospective Evaluation of Intravitreal Triamcinolone Acetonide Injection in Macular Edema Associated with Retinal Vascular Disorders

Purpose

To evaluate the effect of intravitreal triamcinolone acetonide on visual acuity and macular thickness using optical coherence tomography (OCT) in macular edema associated with various retinal vascular disorders.

Methods

This prospective nonrandomized clinical interventional study included 81 eyes (76 patients) comprised of Group I, 57 eyes (51 patients) with diabetic macular edema; Group II, 10 eyes (10 patients) with branch retinal vein occlusion; and Group III, 13 eyes (13 patients) with central retinal vein occlusion. All eyes received an intravitreal injection of 4 mg triamcinolone acetonide (with the solvent) in the operation theater under sterile conditions.

Results

Mean preinjection central macular thickness was 531.84±132 μm in Group I, 458.4±149 μm in Group II, and 750.81±148 μm in Group III. All groups showed a statistically significant decrease in mean central macular thickness at 1 month (300.7±119 μM in Group I, 218.2±99 μm in Group II, and 210.5 ±56 μm in Group III) and 3 months (253.19±109 μm in Group I, 187±47 μm in Group II, and 182±50 μm in Group III) after injection (p<0.05). Mean follow-up was 22±2.4 weeks. Mean visual acuity increased in all three groups (preoperative visual acuity in Group I, 1.2±0.4 logMAR units; Group II, 1.24±0.5 logMAR units; Group III, 1.1 ±0.4 logMAR units; 1 month postinjection in Group I, 0.88±0.3 logMAR units; Group II, 0.67±0.3 logMAR units; Group III, 0.86±0.4 logMAR units; 3 months postinjection in Group I, 0.84±0.4 logMAR units; Group II, 0.59±0.3 logMAR units; Group III, 0.82±0.5 logMAR units) (p<0.05). Forty-one eyes completed 6 months and 20 eyes completed 9 months follow-up. Twelve of 20 (41%) eyes in Group I, 2/6 (33%) eyes in Group II, 3/6 (50%) eyes in Group III, and 8/15 (53%) eyes in Group I, 1/3 (33%) eyes in Group II, and 2/2 (100%) eyes in Group III developed recurrence of macular edema with worsening of visual acuity at 6 and 9 months, respectively. Thirty-three (40.7%) eyes developed IOP elevation (at least one reading > 24 mmHg). One eye developed infective endophthalmitis.

Conclusions

Intravitreal injection of triamcinolone acetonide may be considered as an effective treatment for reducing macular thickening due to diffuse diabetic macular edema, venous occlusion associated macular edema, and may result in increase in visual acuity at least in the short term. Further follow-up and analysis is required to demonstrate its long-term efficacy.

SCLEROTOMY LEAKAGE IN TRANSCONJUNCTIVAL SMALL-GAUGE PARS PLANA VITRECTOMY: Effect of Removing the Cannula Over the Light Pipe

PURPOSE

To determine the effect of cannula removal over the light pipe on the incidence of sclerotomy leakage and to evaluate other factors that may influence the incidence of sclerotomy leaks and hypotony on conclusion of small-gauge transconjunctival pars plana vitrectomy.

METHODS

Retrospective, interventional clinical study of consecutive patients who underwent small-gauge transconjunctival pars plana vitrectomy at a single academic center. Eyes were divided into a group in which cannulae were removed over the light pipe (Group L) and a group in which cannulae were simply pulled out (Group N). The primary comparison was the comparison in requirement for suturing of sclerotomies between Groups L and N.

RESULTS

Forty-eight eyes of 48 patients were included in the study (Group L: 21 eyes; Group N: 27 eyes). In Group L, 14/42 (33%) superior sclerotomies required suturing compared with 7/54 (13%) sclerotomies in Group N (P = 0.024). Superior sclerotomy leaks were also more common in Group L (28/42, 67%) compared with Group N (23/54, 43%, P = 0.024). Similarly, more eyes had hypotony after cannula removal in Group L (11/21; 52%) compared with Group N (5/27; 19%, P = 0.03). There were no differences in any of these measures when comparing fluid-filled to air- or gas-filled eyes.

CONCLUSION

Removing the cannula over the light pipe results in a greater frequency of leaking, including leaking that results in hypotony or that requires suturing. The technique of cannula removal affects the risk of leakage and the risk of requiring suturing of a sclerotomy.

Postoperative Endophthalmitis: A Review of Risk Factors, Prophylaxis, Incidence, Microbiology, Treatment, and Outcomes

Postoperative endophthalmitis is one of the most feared complications of intraocular surgery. The most common types of intraocular surgeries performed worldwide are cataract extraction, glaucoma drainage implants/trabeculectomy, and pars plana vitrectomy. This review will focus on the clinical features, risk factors, prophylaxis, and treatment of endophthalmitis in these three main intraocular surgeries.

Acute bacterial endophthalmitis after scleral buckling surgery with chandelier endoillumination

Purpose

The non-contact wide-angle viewing system (WAVS) with chandelier endoillumination is being used more commonly during scleral buckling surgery for rhegmatogenous retinal detachments although its safety has not been established. We report our findings in a case of bacterial endophthalmitis that developed after scleral buckling surgery with WAVS and chandelier endoillumination.

Observations

A 42-year-old man underwent scleral buckling surgery for a rhegmatogenous retinal detachment in his right eye using a WAVS with chandelier endoillumination. Three days after the surgery, the patient noticed a marked decrease in his vision with ocular pain. Slit-lamp examination showed dense infiltration in the anterior chamber and vitreous body. Pars plana vitrectomy with antibiotic irrigation was done immediately, and Staphylococcus epidermidis was detected in the vitreous fluid. After vancomycin 6/day for 4 weeks, the inflammation gradually subsided, and the visual acuity recovered to 20/20 in 3 months.

Conclusions and importance

Acute bacterial endophthalmitis can develop after scleral buckling surgery performed with WAVS and chandelier endoillumination.

Survey of intravitreal injection techniques among retina specialists in Israel

Purpose

The purpose of this study was to describe antivascular endothelial growth factor intravitreal injection techniques of retinal specialists in order to establish a cornerstone for future practice guidelines.

Methods

All members of the Israeli Retina Society were contacted by email to complete an anonymous, 19-question, Internet-based survey regarding their intravitreal injection techniques.

Results

Overall, 66% (52/79) completed the survey. Most (98%) do not instruct patients to discontinue anticoagulant therapy and 92% prescribe treatment for patients in the waiting room. Three quarters wear sterile gloves and prepare the patient in the supine position. A majority (71%) use sterile surgical draping. All respondents apply topical analgesics and a majority (69%) measure the distance from the limbus to the injection site. A minority (21%) displace the conjunctiva prior to injection. A majority of the survey participants use a 30-gauge needle and the most common quadrant for injection is superotemporal (33%). Less than half routinely assess postinjection optic nerve perfusion (44%). A majority (92%) apply prophylactic antibiotics immediately after the injection.

Conclusion

The majority of retina specialists perform intravitreal injections similarly. However, a relatively large minority performs this procedure differently. Due to the extremely low percentage of complications, it seems as though such differences do not increase the risk. However, more evidence-based medicine, a cornerstone for practice guidelines, is required in order to identify the intravitreal injection techniques that combine safety and efficacy while causing as little discomfort to the patients as possible.

Endophthalmitis following intravitreal anti-vascular endothelial growth factor (VEGF) injection: a comprehensive review

The purpose of this review is to report and summarize previously reported studies and assess many of the individual steps of the intravitreal injection procedure's possible effect on the prevention of endophthalmitis. The pooled endophthalmitis rate from 20 large retrospective case series of anti-VEGF injections was 144/510,396 (0.028%; 1/3,544). Injections may be performed in an office-based location or in an operating room (OR) and low rates of endophthalmitis can be achieved in either location with careful attention to asepsis. Pre- or post-injection topical antibiotics have not been shown to be effective, and could select for more virulent microorganisms. Povidone-iodine prior to injection is accepted as the gold-standard antiseptic agent, but aqueous chlorhexidine may be an alternative. Antisepsis before and after gel or subconjunctival anesthetic is suggested. The preponderance of Streptococcal infections after intravitreal injection is discussed, including the possible role of aerosolization, which can be minimized by using face masks or maintaining silence. As with other invasive procedures in medicine, the use of sterile gloves, following adequate hand antisepsis, may be considered. Control of the eyelashes and lid margin is required to avoid contamination of the needle, but this can be achieved with or without a speculum. Techniques to minimize vitreous reflux have not been shown to reduce the risk of endophthalmitis. Same day bilateral injections should be performed as two separate procedures, preferably using drug from different lots, especially when using compounded drugs.

Endophthalmitis following pars plana vitrectomy: a literature review of incidence, causative organisms, and treatment outcomes

Endophthalmitis following pars plana vitrectomy is a very uncommon cause of endophthalmitis. Cases reported over the last decade show a decrease in incidence over time. To optimize visual outcome, early diagnosis and treatment are essential. In this review we report a summary of the incidence of endophthalmitis following vitrectomy, various risk factors for their occurrence, the microbiological profile and the visual outcomes post treatment.

Survey of intravitreal injection techniques and treatment protocols among retina specialists in Canada

OBJECTIVE

To describe intravitreal injection (IVI) techniques and treatment protocols by retina specialists in Canada from August 1, 2012, to October 1, 2012.

DESIGN

Cross-sectional survey.

PARTICIPANTS

All fellowship-trained retina specialists across Canada, as identified from the Canadian Ophthalmological Society directory and the Canadian Retina and Vitreous Society directory.

METHODS

An anonymous 28-question survey was sent to 125 retina specialists across Canada by email. Reminder letters were sent by email, mail, and fax as necessary.

RESULTS

A total of 75 (63%) retina specialists responded to the survey. Most IVIs were performed in the office. Most surgeons did not use gloves (61%), sterile draping (91%), or surgical mask (71%). Antisepsis was used on conjunctiva by 100% and on periocular skin by 48%. Nearly all specialists used a sterile lid speculum (91%). Common anaesthetics included topical proparacaine or lidocaine drops (90%), topical lidocaine gel (25%), topical pledget (23%), and subconjunctival lidocaine injections (23%). Most (83%) dilate the pupil before IVI. Prophylactic topical antibiotics were used by 43%; 50% of these were started immediately after IVI. Injection location was estimated by visualization by 45%. A majority (63%) inject inferotemporally. Anterior chamber paracentesis was performed routinely by 5%. Optic nerve perfusion was formally assessed by 48%. The most common treatment protocol for age-related macular degeneration was treat and extend. For both diabetic and retinal vein occlusion-related macular edema, the most common protocol was 3 initial monthly injections with PRN follow-up.

CONCLUSIONS

A wide variety of IVI practice patterns exist in terms of aseptic technique, anaesthetics, prophylactic antibiotics, postinjection monitoring, and treatment protocol.

Influence of the source of incisional vitreous incarceration on sclerotomy closure competency after transconjunctival sutureless vitrectomy

PURPOSE

To evaluate the influence that the origin of incisional vitreous incarceration may have on the presence of postoperative conjunctival blebs over sclerotomies after transconjunctival sutureless vitrectomy (TSV). Blebs are formed by incisional leakage due to incompetent closure.

METHODS

Twenty-three-gauge TSV was performed in 83 cadaveric pig eyes. Once each vitrectomy was finished, ultrasound biomicroscopy (UBM) was used to assess the presence of postoperative conjunctival blebs over the sclerotomy sites, as well as the existence of vitreous incarcerated in incisions. Vitreous strands may come from the perisclerotomy area, running parallel to the sclera toward the inner hole of the sclerotomies, or may radiate from the core of the vitreous cavity.

RESULTS

Vitreous entrapment was found in 73.9% of the sclerotomies; 43.4% of the incisions showed vitreous strands coming parallel to the sclera (12.9% of them showed conjunctival bleb), 19.7% of the wounds presented vitreous aiming toward the core of the vitreous cavity (2% of them had conjunctival bleb) and 10.8% of the entrances presented both vitreous incarceration sources (none of them showed bleb). Incisions with vitreous entrapment parallel to the sclera were associated with a significantly greater sclerotomy leakage rate.

CONCLUSIONS

Sclerotomies with vitreous incarceration coming from the core of the vitreous cavity showed a greater incisional closure competency than that observed in incisions with vitreous entrapment coming from the pericannular area; if these results were confirmed in humans, different postoperative suture rates may be expected on sclerotomies according to the vitrectomy degree performed in different areas of the vitreous cavity.

Intraoperative endoscopic observation of sclerotomy site after cannula removal for 23-gauge vitrectomy

BACKGROUND

The purpose of this study was to determine the incidence of vitreous incarceration in sclerotomy after cannula removal during 23-gauge vitrectomy.

METHODS

Thirty-seven eyes underwent 23-gauge sutureless vitrectomy. Oblique sclerotomies were made parallel to the limbus and tangentially to the sclera. Once past the trocar sleeve, the angle was changed to 90 degrees perpendicular to the surface and the trocar and cannula inserted. Vitreous gel was removed until the intraocular edge of the infusion cannula was free from the gel. The cannula was extracted with insertion of a light probe. The sclerotomy site was evaluated endoscopically through another cannula in 32 eyes; in five eyes, another infusion tube was inserted into the cannula to maintain intraocular pressure, the original infusion was removed, and the sclerotomy site observed.

RESULTS

No vitreous incarceration occurred in 30 (94%) eyes when one cannula was removed with insertion of a light probe, and minimal incarceration occurred in two (6%) eyes. No incarceration occurred in five eyes with observation of the infusion site.

CONCLUSION

The incidence of vitreous incarceration is low when a light probe or vitreous cutter is inserted. Inserting the light probe through the cannula during its removal and creating an oblique sclerotomy may reduce vitreous incarceration.

Endophthalmitis Associated with Intravitreal Anti-Vascular Endothelial Growth Factor Injections

The use of anti-vascular endothelial growth factor (VEGF) agents has led to a dramatic increase in the number of intravitreal injections. Endophthalmitis remains a rare but potentially vision-threatening complication of intravitreal injections. Recent large series have estimated this risk to be about one in 3,000 injections or less. Bevacizumab, which is generally prepared by a compounding pharmacy, is associated with additional risks of contamination. Although endophthalmitis cannot be prevented in all cases, certain risk reduction strategies have been proposed, including the use of an eyelid speculum, povidone iodine, avoidance of needle contact with the eyelid margin or eyelashes, and avoidance of routine post-injection antibiotics. Despite these precautions, some patients will develop endophthalmitis following intravitreal anti-VEGF injections, and outcomes may be poor despite prompt and appropriate therapy.

Influence of sclerotomy use on vitreous incarceration in an experimental model of vitrectomized eye

PURPOSE

To evaluate the influence of sclerotomy use during vitrectomy (vitreous cutter, illumination probe, or infusion-line entrance) on postoperative vitreous incarceration using an experimental model of vitrectomized eye.

MATERIALS AND METHODS

Experimental, randomized, and observer-masked study in which 23-gauge transconjunctival sutureless vitrectomy was performed in cadaveric pig eyes. Postoperative incisional vitreous entrapment was evaluated by direct visualization. No vitreous incarceration was classified as grade 0 (G0), thin vitreous entrapment was classified as grade 1 (G1), and thick vitreous strands as grade 2 (G2).

RESULTS

A total of 46 eyes were included. Vitreous incarceration was detected in 91.3% (43.5% G1, 47.8% G2) of the sclerotomies used by the vitreous cutter probe, 95.7% (45.7% G1, 50% G2) of the illumination-pipe entrances, and 93.5% (45.7% G1, 47.8% G2) of the infusion-line incisions. No statistical differences were found when comparing incisional vitreous incarceration after vitrectomy according to sclerotomy use.

CONCLUSION

Different manipulation of the sclerotomies, depending on their use, does not seem to influence postvitrectomy vitreous entrapment in our experimental model.

[Bacterial contamination of needles after intravitreal injection in Paraguay]

PURPOSE

The study was designed to prospectively evaluate the bacterial contamination of needles used for intravitreal injection during surgery.

MATERIAL AND METHODS

Between December 2007 and December 2010, 549 eyes of 413 patients were treated with intravitreal injections of 1.25 mg bevacizumab. Of the patients 322 received a single injection and 91 multiple injections. Preoperatively the periorbital skin of all patients was treated with 10% povidone iodine (PVI) and the conjunctival sac was irrigated with 1% PVI. No pre-injection antibiotics were administered. Immediately after the injection the needles were rinsed 3 times in thioglycolate broth which was then cultured at 37°C for 5 days. As a negative control 73 sterile unused needles were treated in the same way.

RESULTS

Out of the 549 needle points tested 8 (1,45%) were found to be contaminated after intravitreal injections. The isolated bacteria were coagulase negative Staphylococcus (n = 7), Propionibacterium acnes (n = 1) and Klebsiella pneumoniae (n = 1) (co-contamination in one case).

CONCLUSION

Contamination of needles is minimal after prophylactic povidone iodine irrigation before intravitreal injections. Therefore, this prophylaxis technique is recommended before intravitreal injections in order to prevent postoperative infections.

Exogenous endophthalmitis in diabetic patients: a systemic review

Diabetes mellitus is a systemic disease that increases the risk of infections. Exogenous endophthalmitis is an inflammatory disease to which diabetic patients are more predisposed to than nondiabetic patients undergoing any intraocular intervention. This might be because of the change in the immune and inflammatory factors that intervene in wound healing and in the bacterial flora of the ocular adnexa. We conducted a literature review to assess the risk of exogenous endophthalmitis in diabetic patients undergoing cataract extraction, pars plana vitrectomy, and intravitreal injections and to check whether its treatment differ from in non-diabetics. We found that diabetic patients are more predisposed to virulent organisms and that the incidence of ophthalmic symptoms was not substantially different in diabetic versus nondiabetic patients. Regarding treatment, all patients with light perception should receive pars plana vitrectomy, while those with hand motion and better vision should be given an intravitreal antibiotics injection. Some authors recommend vitrectomy to diabetic patients with even counting figure vision.

Effect of interposition maneuver during cannula removal on vitreous incarceration rate in vitrectomized eyes measured by ultrasound biomicroscopy

PURPOSE

To evaluate the influence of the cannula removal maneuver on the postoperative incisional vitreous incarceration using an experimental model of vitrectomized eye.

METHODS

Prospective, experimental, randomized and observer-masked experimental study in which 23-gauge transconjunctival sutureless vitrectomy was performed through oblique sclerotomies in cadaveric pig eyes. Once the vitrectomy was finished, one of the superior cannulas was removed with the light probe introduced through it, and the other cannula was extracted with the cannula plug inserted. Postoperative incisional vitreous incarceration was evaluated by ultrasound biomicroscopy (UBM).

RESULTS

60 eyes included. Considering the 60 superior sclerotomies whose cannulas were extracted with the light pipe inserted, vitreous incarceration was observed in 35% of them. On the other hand, 71.6% of the incisions whose cannulas were removed with the cannula plug inserted showed vitreous incarceration (p = 0.00013).

CONCLUSIONS

Interposing the light probe through the cannula when it is removed seems to reduce the postoperative wound vitreous incarceration rate in our experimental model.

Incidence of damage to the crystalline lens during intravitreal injections

PURPOSE

To report the incidence of traumatic lens injuries as a complication of intravitreal injection at 5 high-volume academic centers.

METHODS

We determined in a retrospective, interventional, multicenter case series the consecutive number of the injections between January 5, 2006 and December 22, 2008 from the injection log books. All injections were performed under sterile conditions in a laying position, 3.5-4.0 mm behind the limbus in an oblique fashion. The main outcome measure was the incidence of lens damage.

RESULTS

A total of 32,318 intravitreal injections were performed, and 3 cases of iatrogenic lens damage were reported during 36 consecutive months. All affected eyes were hyperopic. The overall incidence rate of lens injury was 0.006% (2/32,318) for intravitreal injections and 1 during a paracentesis 0.003 (1/32,318). The rate of phakic eyes determined was 67%, and thus, the incidence rate of lens damage in phakic eyes was 0.009% (2/21,653) (95% confidence interval, 0.00%-0.05%).

CONCLUSIONS

Although there is no agreement regarding the proper intravitreal injection technique, the incidence of traumatic injuries to the crystalline lens was very low in a large series of injected patients in a community setting. The incidence compares favorably with that reported in clinical trials in which much more extensive preinjection preparation was mandated. A good preparation of the surgical incision with proper anesthesia and detailed information of the patient, as well as good anatomical skills of the treating physician, are mandatory to prevent this rare adverse event.

Survey of intravitreal injection techniques among retinal specialists in the United States

PURPOSE

To describe the intravitreal injection technique practice patterns of retinal specialists in the United States from April 8, 2010 to April 21, 2010.

DESIGN

Questionnaire survey.

METHODS

All members of the American Academy of Ophthalmology who self-categorized as "Retinal/Vitreous Surgery" were contacted by e-mail to complete an anonymous, 20-question, internet-based survey.

RESULTS

A total of 765 retinal specialists (44%) responded to the survey. Most respondents wear gloves (58%) and use an eyelid speculum (92%) when performing an intravitreal injection. More than 99% use povidone-iodine preinjection. The majority measure the injection site from the limbus (56%) and inject straight into the vitreous cavity (96%). Most do not displace the conjunctiva (83%). Seventy-two percent routinely assess postinjection optic nerve perfusion, primarily by gross visual acuity measurement (32%). While nearly one third of participants use prophylactic topical antibiotics preinjection, more than two thirds use topical antibiotics postinjection. Forty-six percent perform bilateral simultaneous intravitreal injections. The majority of respondents use a 30-gauge needle for the injection of ranibizumab (78%) and bevacizumab (60%). However, respondents use both a 27- and 30-gauge needle for the injection of triamcinolone acetonide.

CONCLUSIONS

Retinal specialists in the United States participate in a range of techniques for the care before, during, and after intravitreal injections. Further study is needed to elucidate best practice patterns.

[Three-dimensional visualization of sclerotomies with ultrasound biomicroscopy. Comparison of 20 and 23 gauge incisions on the porcine eyeball]

BACKGROUND

When pars plana vitrectomy is performed, the sizes of the sclerotomy cannula vary between 20 and 23 gauge. We examined the morphology of the scleral tunnels by ultrasound biomicroscopy additionally taking into account the incision angle.

MATERIAL AND METHODS

In each of 16 enucleated porcine eyes three 20 or 23 gauge sclerotomies with varying angles between 30 and 90° to the horizontal level were performed. The vertical 20 gauge sclerotomies were additionally sealed by 7.0 vicryl cross-stitching. The resulting scleral channels were analysed by 3-D ultrasound biomicroscopy.

RESULTS

The sclerotomies were echographically detectable in all cases. Analysis revealed that the sutured straight 20 gauge tunnels were hyporeflective in only some parts while the other incisions showed continuous hyporeflectivity along the complete channel in many cases. The smaller the instruments used and the flatter the scleral angles chosen, the smaller were the measured widths of the incision tunnels.

CONCLUSION

Imaging sclerotomies ex vivo by ultrasound biomicroscopy is reliably reproducible. In the echographic pictures straight 20 gauge incisions appeared to be safely sealed by the sutures while the nonsealed tunnels often showed continuous patency. By choosing small instruments and flat incision angles the width of the resulting scleral channels can be reduced.

Bacterial contamination of needles used for intravitreal injections: a prospective, multicenter study

PURPOSE

To determine the incidence of bacterial contamination of needles used for intravitreal injections.

METHODS

Patients undergoing intravitreal injections were enrolled prospectively. No pre-injection antibiotics were administered. Following povidone-iodine irrigation, conjunctival cultures were taken and the injection was performed. The needle was cultured. A dry control needle was exposed to the surgical field and cultured.

RESULTS

No patients developed endophthalmitis. Eighteen injection needles (18%) yielded positive bacterial growth. The most commonly encountered organisms were Propionibacterium acnes (n = 8) and Staphylococcus epidermidis (n = 6). Four control needles showed positive growth, in 2 cases with the same organism as a matching positive used needle. The difference between contamination rates of used and control needles was significant (p = .002, McNemar's test).

CONCLUSIONS

Bacterial contaminants are present on a substantial proportion of needles. Since the needle contacts both the ocular surface and the vitreous, it is possible that inoculation of the vitreous cavity occurs in such cases.

Antibiotic resistance of conjunctiva and nasopharynx evaluation study: a prospective study of patients undergoing intravitreal injections

PURPOSE

To determine the baseline antibiotic susceptibility patterns of conjunctival and nasopharyngeal flora isolated from patients undergoing intravitreal (IVT) injections for choroidal neovascularization (CNV).

DESIGN

Prospective, observational study.

PARTICIPANTS

Forty-eight eyes of 24 patients undergoing unilateral IVT injections for CNV.

METHODS

Bilateral conjunctival and unilateral nasopharyngeal cultures on the treatment side were taken before application of any topical medications.

MAIN OUTCOME MEASURES

Bacterial isolates were identified and tested for antibiotic susceptibility to 16 different antibiotics using the Kirby-Bauer disc diffusion technique.

RESULTS

A total of 57 bacterial isolates were obtained from the conjunctiva of 48 eyes. Coagulase-negative staphylococci (CNS) accounted for 37 of the 57 isolates (65%). The most common CNS organisms were Staphylococcus epidermidis and Staphylococcus lugdunensis accounting for 73% and 11% of CNS isolates, respectively. More than half of S. epidermidis isolates demonstrated some level of resistance to ofloxacin and levofloxacin, and 33% and 37% of isolates showed some level of resistance against gatifloxacin and moxifloxacin, respectively. Some 60% and 30% of CNS isolates were resistant to ≥ 3 and ≥ 5 antibiotics, respectively. Among the 24 nasopharyngeal cultures, 8 (33%) grew Staphylococcus aureus, and 1 of the 8 isolates (13%) was resistant to all penicillin, cephalosporin, macrolide, and fluoroquinolone antibiotics tested.

CONCLUSIONS

Our results demonstrate subtantial levels of resistance to third- and fourth-generation fluoroquinolones and multiresistance among ocular CNS isolated from patients undergoing IVT injections for CNV.

The effects of injection site on the reflux following intravitreal injections

BACKGROUND

This study aimed to investigate the effects of injection site on the reflux after intravitreal injection.

METHODS

One hundred and eighty eyes undergoing intravitreal injection including 0.1 ml of triamcinolone acetonide or bevacizumab or pegaptanib were divided to six groups (30 patients in each group) to compare the vitreal reflux after injection using superotemporal versus inferotemporal quadrant. The amount of intraoperative reflux was estimated by measuring the width of the subconjunctival bleb. An interventional, prospective, comparative clinical trial was applied.

RESULTS

The mean bleb width as the reflux amount after injection of three drugs was statistically less after the inferotemporal injection (1.50 ± 0.94 mm for triamcinolone acetonide, p < 0.001; 1.60 ± 1.07 mm for bevacizumab, p < 0.001; and 1.77 ± 0.94 mm for pegaptanib, p = 0.001) than those in eyes undergoing the superotemporal injection (3.20 ± 1.63 mm for triamcinolone acetonide; 3.07 ± 1.53 mm for bevacizumab; and 2.80 ± 1.32 mm for pegaptanib).

CONCLUSIONS

The injection through inferotemporal quadrant provides statistically significant less vitreal reflux for intravitreal drug injection.

KEYWORDS

Intravitreal injection; Injection site; Reflux.

[Intravitreal injection. Monitoring to avoid postoperative complications]

Intravitreal injection is generally regarded as safe. Many of the potential complications caused by this procedure are extremely rare and can be avoided by careful inspection beforehand and proper performance of the injection. In rare cases, however, the administered drugs may cause various pharmacological side effects. This article summarizes the safety profiles of Macugen and Lucentis from the drug approval studies and describes initial findings on possible or observed side effects after intravitreal administration of Avastin. In addition, important points to observe in order to avoid intra- and postoperative complications are provided.

Vitreous wicking syndrome as a complication of extracapsular cataract extraction

BACKGROUND

Vitreous wicking syndrome is most commonly associated with cataract surgery. This is a phenomenon whereby the vitreous prolapses through a corneal or scleral wound forming a "wick" on the extraocular surface. Multiple complications have been associated with vitreous wicking, including endophthalmitis, cystoid macular edema, and pupillary block glaucoma.

CASE REPORT

This article presents 2 cases of vitreous wicking, both after extracapsular cataract extraction. The first case represents a more typical presentation, whereas the second case represents an associated complication.

CONCLUSION

With optometrists more involved in postoperative care, associated complications such as vitreous wick syndrome after intraocular surgery must be recognized, and management of these cases must be handled appropriately to prevent vision-threatening complications.

Conjunctival necrosis following intravitreal injection of triamcinolone acetonide

PURPOSE

To report a case of localized conjunctival necrosis following intravitreal injection of triamcinolone acetonide (TA).

DESIGN

Single observational case report.

METHODS

A 63-year- old man presented with inferotemporal branch retinal vein occlusion and macular edema in his left eye (OS). He underwent pars plana vitrectomy combined with arteriovenous sheathotomy. Postoperatively, as the macular edema persisted, he underwent an uneventful intravitreal injection of TA.

RESULTS

Ten days following the intravitreal injection, he presented with an area of localized conjunctival necrosis overlying the scleral entry site. Gram stain showed a few white blood cells and no organisms. The conjunctival swab showed no growth on culture. The area of conjunctival necrosis responded well to intense topical antibiotic therapy.

CONCLUSIONS

Conjunctival necrosis is a rare anterior segment complication of intravitreal injection of TA. With the increased usage of intravitreal TA for various posterior segment disorders, the treating physician should be aware of this complication.

National survey of the technique of intravitreal triamcinolone injection in the United Kingdom

OBJECTIVES

Intravitreal injection of steroids is a rapidly evolving treatment option for a variety of retinal pathologies. There is wide variation among ophthalmologists regarding dose of steroid and the technique of injection. Through this survey we aim to describe the current practice of injection of intravitreal steroid among ophthalmic consultants in the United Kingdom and review the literature.

METHODS

A postal questionnaire was sent to all the 901 ophthalmic consultants in the United Kingdom. The questions covered frequency of intravitreal steroid injections, subspecialty interest, dosage and volume of steroid, patient preparation, surgeon preparation, and postoperative management.

RESULTS

The response rate to the questionnaire was 63%. A total of 24.7% perform intravitreal steroid injections regularly with 90% of users performing five or fewer injections per month. In all, 94% use a dose of 4 mg. Among surgeons, 38% do not prescribe postoperative antibiotics or steroids and 59% check intraocular pressure either on the same or the next day.

CONCLUSION

The relatively short experience with this technique has not yet allowed a clear picture to emerge of indications, complications or best practice administration. Published descriptions of intravitreal steroid injection techniques vary widely and variations are not evidence based. Observed UK practice is diverse.