Robert G. Devenyi

Incidence of Endophthalmitis and Use of Antibiotic Prophylaxis after Intravitreal Injections

PURPOSE To report the incidence of endophthalmitis in association with different antibiotic prophylaxis strategies after intravitreal injections of anti-vascular endothelial growth factors and triamcinolone acetonide. DESIGN Retrospective, comparative case series. PARTICIPANTS Fifteen thousand eight hundred ninety-five intravitreal injections (9453 ranibizumab, 5386 bevacizumab, 935 triamcinolone acetonide, 121 pegaptanib sodium) were reviewed for 2465 patients between January 5, 2005, and August 31, 2010. The number of injections was determined from billing code and patient records. METHODS The indications for injection included age-related macular degeneration, diabetic macular edema, central and branch retinal vein occlusion, and miscellaneous causes. Three strategies of topical antibiotic prophylaxis were used by the respective surgeons: (1) antibiotics given for 5 days after each injection, (2) antibiotics given immediately after each injection, and (3) no antibiotics given. MAIN OUTCOME MEASURES The primary outcome measures were the incidence of culture-positive endophthalmitis and culture-negative cases of suspected endophthalmitis. RESULTS Nine eyes of 9 patients with suspected endophthalmitis after injection were identified. Three of the 9 cases had culture-positive results. The overall incidence of endophthalmitis was 9 in 15 895. The incidence of culture-negative cases of suspected endophthalmitis and culture-proven endophthalmitis after injection was 6 in 15 895 and 3 in 15 895, respectively. Taking into account both culture-positive endophthalmitis and culture-negative cases of suspected endophthalmitis, the incidence per injection was 5 in 8259 for patients who were given antibiotics for 5 days after injection, 2 in 2370 for those who received antibiotics immediately after each injection, and 2 in 5266 who received no antibiotics. However, if considering culture-proven endophthalmitis alone, the use of topical antibiotics, given immediately or for 5 days after injection, showed lower rates of endophthalmitis compared with those without postinjection antibiotics. The risk of endophthalmitis after intravitreal injection varied among agents that were used. Among the 9 cases of clinically suspected endophthalmitis, regardless of prophylactic strategies used, the incidence of endophthalmitis per injection was 2 in 935 for triamcinolone acetonide, 3 in 9453 for ranibizumab, and 4 in 5386 for bevacizumab. CONCLUSIONS The overall rate of intravitreal injection-related endophthalmitis is greater with the use of topical antibiotics, given immediately or for 5 days after the injection, compared with no antibiotics.

Risk Factors for Acute Endophthalmitis after Cataract Surgery: A Population-based Study

OBJECTIVE To identify risk factors for suspected acute endophthalmitis after cataract surgery. DESIGN Population-based retrospective cohort. PARTICIPANTS Administrative data from more than 440,000 consecutive cataract surgeries in Ontario, Canada, from April 1, 2002, to March 31, 2006. METHODS Consecutive physician billing claims for cataract surgery and specific intraoperative and postoperative procedures related to complications of cataract surgery were identified. Acute endophthalmitis was defined using surrogate markers for intraocular infection, including vitrectomy, vitreous injection, or aspiration procedures not in combination with air/fluid exchange or dislocated lens extraction, performed 1 to 14 days after cataract surgery. Anterior vitrectomy performed on the day of surgery was used as a surrogate marker for capsular rupture. MAIN OUTCOME MEASURES Overall rates of endophthalmitis were calculated and grouped by patient demographics, surgical facility, season, year, and association with capsular rupture. RESULTS There were 617 suspected acute endophthalmitis cases of 442,177 cataract surgeries over the 4 years. The overall unadjusted and adjusted rates of suspected acute endophthalmitis were both 1.4 per 1000 cataract surgeries. Men had higher rates than women (1.70 vs. 1.19/1000 surgeries, P<0.0001) with an adjusted odds ratio of 1.40 (95% confidence interval, 1.19-1.64).The oldest age group (>or= 85 years) had the highest rate (2.18/1000), and the youngest group (20-64) had the second highest rate (1.76/1000). The endophthalmitis rates for these age groups were significantly different from those aged 65 to 84 years. The endophthalmitis rate was approximately 10-fold higher in those with capsular rupture compared with those without (13.11 vs. 1.34/1000, P<0.0001), with an adjusted odds ratio of 9.56 (95% confidence interval, 6.43-14.2). CONCLUSIONS The overall rates of suspected acute endophthalmitis are low but significantly higher in certain patient groups. Our population-based analysis can be used as a benchmark for quality-improvement initiatives and can assist clinicians in educating their patients regarding the risks associated with cataract surgery. Future work is required to address the higher rate of endophthalmitis in men, those with capsular rupture, and the oldest patients undergoing cataract surgery.

TREAT-AND-EXTEND REGIMENS WITH ANTI-VEGF AGENTS IN RETINAL DISEASES: A Literature Review and Consensus Recommendations.

Purpose: A review of treat-and-extend regimens (TERs) with intravitreal anti–vascular endothelial growth factor agents in retinal diseases. Methods: There is a lack of consensus on the definition and optimal application of TER in clinical practice. This article describes the supporting evidence and subsequent development of a generic algorithm for TER dosing with anti–vascular endothelial growth factor agents, considering factors such as criteria for extension. Results: A TER algorithm was developed; TER is defined as an individualized proactive dosing regimen usually initiated by monthly injections until a maximal clinical response is observed (frequently determined by optical coherence tomography), followed by increasing intervals between injections (and evaluations) depending on disease activity. The TER regimen has emerged as an effective approach to tailoring the dosing regimen and for reducing treatment burden (visits and injections) compared with fixed monthly dosing or monthly visits with optical coherence tomography–guided regimens (as-needed or pro re nata). It is also considered a suitable approach in many retinal diseases managed with intravitreal anti–vascular endothelial growth factor therapy, given that all eyes differ in the need for repeat injections. Conclusion: It is hoped that this practical review and TER algorithm will be of benefit to health care professionals interested in the management of retinal diseases.

Combined Scleral Buckle and Pars Plana Vitrectomy as a Primary Procedure for Pseudophakic Retinal Detachments

BACKGROUND AND OBJECTIVE Pseudophakic and aphakic retinal detachments are associated with a lower percentage of successful primary repair with standard scleral buckling surgery, than phakic retinal detachments. The objective of this study was to determine whether a combined scleral buckle and vitrectomy, as a primary procedure, offers any advantage over conventional scleral buckling in primary pseudophakic and aphakic retinal detachments, without proliferative vitreoretinopathy. MATERIALS AND METHODS This was a prospective, non-randomized clinical study. Ninety-four consecutive pseudophakic and aphakic retinal detachments were included in the study. All patients were operated upon by the same surgeon. Each patient underwent a combined scleral buckle and pars plana vitrectomy with perfluorocarbon injection and air-fluid exchange. Each patient was followed by the operating surgeon for a minimum of 6 months. Patients were followed with respect to anatomic reattachment, visual acuity improvement, and surgical complications. RESULTS All eyes were anatomically reattached after a single operation. All demonstrated an increase in their visual acuity, and there were no complications attributable to the vitrectomy procedure. CONCLUSIONS We conclude that such a combined approach to primary pseudophakic and aphakic retinal detachments offers significant benefits to scleral buckling alone. We believe that the improved success rate is a function of vitrectomy contributing to both an improved peripheral visibility, resulting in fewer missed peripheral breaks, and a lower likelihood of proliferative vitreoretinopathy. We recommend this combined surgical approach for all primary pseudophakic and aphakic retinal detachments.

A Comparison of Peribulbar and Retrobulbar Anesthesia for Vitreoretinal Surgical Procedures

OBJECTIVE To compare the efficacy of retrobulbar and peribulbar anesthetic techniques for vitreoretinal surgical procedures. DESIGN Prospective, randomized, double-blind study. SETTING A large university teaching hospital. PARTICIPANTS One hundred sixteen consecutive patients who were scheduled for vitreoretinal surgical procedures. METHODS Patients who were undergoing vitreoretinal surgical procedures were divided into four separate groups, depending on the type of surgical procedure planned. Equal numbers of patients in each group of patients who were undergoing a surgical procedure were randomly assigned to either the retrobulbar or peribulbar block-treated group. Anesthesia, akinesia, need for block supplementation, and patient acceptance were measured. RESULTS Both retrobulbar and peribulbar anesthetic techniques provided equal levels of akinesia and analgesia, with each requiring intraoperative supplementation in 32%. CONCLUSION Peribulbar block can be expeditiously and efficiently used for a full range of vitreoretinal surgical procedures.

Supraciliary Effusions and Ciliary Body Thickening after Scleral Buckling Procedures

PURPOSE The purpose of the study was to use ultrasound biomicroscopy to identify and quantity changes in anterior segment parameters after scleral buckling procedures. METHODS Ultrasound biomicroscopy was used to examine 15 patients with retinal detachment within 1 week before and after surgery. Quantitative measurements were performed of anterior chamber depth, supraciliary effusion depth, ciliary body thickness, and angle opening. RESULTS Supraciliary fluid was present after surgery in 12 patients (80%). Average supraciliary fluid depth was 0.16 +/- 0.13 mm. Ciliary body thickness measurements at a point 2-mm posterior to the scleral spur increased after surgery in all patients an average of 0.15 +/- 0.10 mm. There was a strong correlation between ciliary fluid levels and change in ciliary body thickness (r = 0.742, P < 0.01). Anterior chamber depth decreased after surgery in 14 patients (93%). A decrease of angle opening of greater than 5 degrees was noted in 11 patients (73%). In all of these 11 patients, the ciliary body and iris root were considered to be rotated anteriorly. Six (55%) of 11 of these patients showed anterior bowing of the iris, indicating pupillary block. Complete angle closure occurred over one to three quadrants in three patients, but none of these patients had complete angle closure or glaucoma. CONCLUSIONS Supraciliary effusions and ciliary body thickening are common after scleral buckling procedures and can produce conditions conducive to angle closure. Angle narrowing occurs through a combination of direct anterior iris rotation and induced pupillary block.

An assessment of intraocular pressure rise in patients with gas-filled eyes during simulated air flight

PURPOSE To investigate the safety of aircraft flight for patients with small volumes of residual postoperative intraocular gas. DESIGN Nonrandomized comparative trial. PARTICIPANTS Seventeen eyes (nine gas filled and eight control eyes) of nine patients and one eye of one control subject were tested. METHODS Patients with postoperative intraocular gas and the control subject were tested in the controlled environment of a hypobaric chamber to simulate the cabin depressurization associated with a typical commercial aircraft flight. Before, during, and after a simulated flight, the intraocular pressure (IOP) in the gas-containing and contralateral eyes was tested using the Perkins (Edinburgh, UK) and Tono-Pen XL (Jacksonville, FL) tonometers. MAIN OUTCOME MEASURES The absolute and percentage change in IOP with varied cabin pressurization. RESULTS Of the nine patients with intraocular gas, seven had 10% to 15% gas volume and two had 20% gas volume. In the 10% to 15% gas volume group, the IOP rose by an average of 109% from baseline during ascent to an average cabin altitude of 7429 feet above sea level. The IOP dropped to an average of 30% above baseline IOP during the cruise phase and further decreased to an average of 38% below baseline IOP on return to baseline altitude. In the 20% gas volume group, the IOP rose by an average of 84% from baseline during ascent to an average cabin altitude of 3400 feet above sea level. The IOP dropped to an average of 42% below baseline IOP on return to baseline altitude. The IOP in the contralateral control eyes did not vary with altitude changes. No patient experienced pain or visual loss during the experiments. CONCLUSIONS Our results demonstrate that IOP may rise significantly in gas-filled eyes during simulated air flight, supporting the current conservative recommendation against air travel for most patients with intraocular gas bubbles. Further testing is warranted to develop a more objective measure of intraocular gas volume estimation and to define better the tolerability of aircraft flight for patients with intraocular gas.

Reproducibility of Topographic Measurements of the Macula with a Scanning baser Ophthalmoscope

BACKGROUND The Heidelberg retina tomograph, a scanning laser ophthalmoscope that uses confocal optics to provide high resolution of images, is able to scan the retina in three dimensions to obtain quantitative topographic measurements. The authors evaluated its usefulness for measuring macular lesions by determining the reproducibility of its topographic measurements at the macula. METHODS For each of ten healthy patients, the authors took five images with the patients right eye undilated and five with the eye cyclopleged and dilated. As a measure of reproducibility, the standard deviation of height measurements for the same location at the macula was calculated for each patient and then the pooled standard deviation for all patients was calculated. The authors performed similar calculations for the mean depth within a contour line. RESULTS The pooled standard deviation for height measurements was 47.4 microns in undilated eyes and 36.0 microns in cyclopleged, dilated eyes. The authors obtained an extremely low standard deviation of 2.2 microns when the software calculated relative differences between measurements, such as the mean depth within a contour line. When the average of three height measurement values on 1 day was compared with the average of the three values on another day, the 95% confidence interval was +/- 58.7 microns for mean height values and +/- 3.7 microns for mean depth values within a contour line. CONCLUSIONS The authors obtained good reproducibility for height measurements with the Heidelberg retina tomograph and excellent reproducibility when the instrument calculated relative differences in height measurements. The authors recommend that patients, especially young patients, be dilated and cyclopleged to obtain lower variability of measurements. The scanning laser ophthalmoscope could potentially be used to quantify small changes in retinal lesions.

Re-operation of idiopathic full-thickness macular holes after initial surgery with internal limiting membrane peel

Background/aims A retrospective consecutive case series to evaluate the efficacy of re-operation in patients with persistent or recurrent idiopathic full-thickness macular hole after initial surgery with internal limiting membrane peel (ILM). Methods 491 patients underwent surgery for full-thickness macular hole from January 2004 to November 2007. Fifty-five patients either did not close or reopened during the follow-up period. Thirty patients with initial ILM peel underwent repeat surgery involving vitrectomy, enlargement of ILM rhexis and gas tamponade. Results Anatomical closure rate was 88.8% for primary surgery and 46.7% (14/30) for re-operation. There was a statistically significant improvement in overall best corrected visual acuity (BCVA) from re-operation baseline BCVA (p=0.02) within 1 year. For holes that did not close after the second surgery, visual acuity did not worsen. Conclusion Re-operation has a reduced success rate of anatomical closure. However, BCVA is statistically significantly improved from re-operation baseline, so even though we cannot return vision to pre-pathological baseline, re-operation can improve on this new baseline.

Retinal blood flow in response to an intravitreal injection of ranibizumab for neovascular age-related macular degeneration

Purpose:  To assess the hemodynamic response of retinal arterioles and venules following a single intravitreal injection of ranibizumab in neovascular age‐related macular degeneration (NV‐AMD) patients and to assess the influence of the number of prior injections on this response.