Wai Ching Lam

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.

Retinopathy in chronic hepatitis C patients during interferon treatment with ribavirin

AIM To assess the ocular effect of interferon alfa 2b prescribed with ribavirin in patients undergoing therapy for chronic hepatitis C. METHODS 19 patients with chronic hepatitis C who satisfied the follow up criteria were assessed for ocular complications using slit lamp biomicroscopy and indirect ophthalmoscopy before, during, and after the treatment at regular intervals. RESULTS 8/19 patients, while on treatment, developed an asymptomatic retinopathy. Among these 3/8 were relapsers and 5/9 were non-responders to interferon monotherapy. All retinal changes faded, often while the patients continued the therapy. There was no significant association in occurrence of retinopathy with haematological and/or biochemical changes. CONCLUSION Retinopathy was more common in interferon monotherapy non-responders than relapsers when treated with interferon alfa 2b with the addition of ribavirin. The changes were transient, disappearing while the patients were still being treated.

Antibiotic Resistance of Ocular Surface Flora With Repeated Use of a Topical Antibiotic After Intravitreal Injection

IMPORTANCE Treatment with intravitreal (IVT) injections has increased during the last several years as evidence has accumulated demonstrating the efficacy of anti-vascular endothelial growth factor agents in the treatment of neovascular age-related macular degeneration (AMD) and various retinal vascular diseases. Although IVT injections are generally safe, infectious endophthalmitis is a rare but devastating complication, and the risk of morbidity and vision loss from endophthalmitis is high. OBJECTIVE To examine the change in antibiotic resistance of ocular surface flora with repeated prophylactic use of antibiotics after IVT injection for AMD. DESIGN AND SETTING Prospective, nonrandomized cohort study in 2 tertiary academic hospitals. PARTICIPANTS Patients 65 years and older with newly diagnosed AMD were recruited by 7 retinal specialists from July 1, 2010, through December 31, 2011. INTERVENTION The study group received topical moxifloxacin hydrochloride for 3 days after each monthly IVT injection. MAIN OUTCOME MEASURE Resistance to moxifloxacin and ceftazidime in cultured isolates at baseline and monthly for 3 months by change in minimal inhibitory concentration (MIC) of culture isolates was studied. RESULTS The study group consisted of 84 patients, and the control group had 94 patients. In the study group, the baseline adjusted MIC increased (from 1.04 to 1.25 μg/mL; P = .01) as did the MIC for 50% of isolates (MIC50) (from 0.64 to 1.00 μg/mL) and the MIC for 90% of isolates (MIC90) (from 0.94 to 4.00 μg/mL). In both groups, the culture-positive rate did not change significantly when adjusted for baseline. No significant change was found in the MIC level, culture-positive rate, MIC50 level, and MIC90 level in the control group. Subgroup analysis found diabetes mellitus to be noncontributory to both the MIC and culture-positive rate. No endophthalmitis or adverse events were reported. CONCLUSIONS AND RELEVANCE Repeated use of topical moxifloxacin after IVT injection significantly increases antibiotic resistance of ocular surface flora. We recommend that routine use of prophylactic antibiotics after IVT injection be discouraged. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01181713.

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.

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.

Deferoxamine-related ocular toxicity: Incidence and outcome in a pediatric population

Purpose: Deferoxamine (DFO) is a chelating agent used widely for the treatment of transfusional hemochromatosis. DFO-related ocular toxicity has been previously reported several times, and many institutions have adopted an ophthalmic screening protocol for patients treated with DFO despite little information regarding the rate of ocular toxicity. Our study aimed to determine the incidence of DFO toxicity at a major pediatric hospital that uses regular ophthalmic screening for all DFO-treated patients. Methods: A retrospective case series of all patients treated with DFO for transfusional hemochromatosis at The Hospital for Sick Children (Toronto, Ontario, Canada) between 1995 and 2005 inclusive. Results: A total of 84 patients received regular DFO treatment for transfusional hemochromatosis related to long-term hypertransfusion. A total of 421 ophthalmic screening examinations were performed (average, 5.0 examinations per patient). DFO-related ocular toxicity was found only in one patient (1.2%). This patient had central blurriness and retinal pigmentary changes shown by examination and decreased central responses shown by electroretinography, but these changes were all found to be completely reversible after a change from intravenous to subcutaneous therapy at a reduced dose. Conclusions: In this large pediatric center, DFO-related ocular toxicity has been a rare and mild finding. Regular ophthalmic screening should be carried out for patients receiving high-dose subcutaneous or intravenous therapy, because early detection of retinal toxicity may lead to optimization of the DFO dose and thus prevention of long-term visual sequelae.

The role of Frizzled-4 mutations in familial exudative vitreoretinopathy and Coats disease

Aim The aim of this study is to assess the role of Frizzled-4 (FZD4) in familial exudative vitreoretinopathy (FEVR) and Coats disease. Methods Tissue samples were collected for DNA extraction and automated DNA sequencing of the two coding exons of FZD4 in both directions. Cases carrying a FZD4 mutation and demonstrating extreme disease severity were selected for direct automated sequencing of all coding exons of LRP5, NDP and TSPAN12. Clinical data were obtained for the purpose of identifying genotype–phenotype correlations. Results 68 probands were diagnosed as having autosomal dominant or sporadic FEVR. Eleven FZD4 mutations (five missense, three deletions, one insertion, two nonsense) were identified. Six of these mutations are novel, and none were found in 346 control chromosomes. In 16 cases of Coats disease, one polymorphism combination was found in two samples: no mutations were detected. No genotype–phenotype correlation emerged. Three severely affected cases with FZD4 mutations failed to show additional mutations in the three other FEVR genes. Conclusion The authors identified 12 FEVR probands with FZD4 mutations. FZD4 mutation screening can be a useful tool especially in mild or atypical cases of FEVR. Germ-line mutations in FZD4 do not appear to be a common cause of Coats disease.

A screening strategy for the detection of sickle cell retinopathy in pediatric patients.

BACKGROUND Children with sickle cell hemoglobinopathy are referred routinely to detect retinopathy and thereby prevent vision-threatening complications. This study aimed to determine the prevalence and age of onset of clinically significant retinopathy in such patients, and to recommend a screening strategy for ophthalmologists. METHODS Two hundred sixty-three pediatric sickle cell patients to a maximum age of 18 years during the period of observation were reviewed for the onset of retinopathy, considering the influence of hemoglobin genotype, gender, and the presence of systemic manifestations. RESULTS Proliferative retinopathy (PR) was rare. Six cases (8.2%) of PR were seen in the SC genotype, 1 case (0.6%) in the SS genotype, and no cases in the SB-Thalassemia genotype. The age of onset of PR was a mean of 13.7 years (median 13, range 9-18) in the SC genotype and 16 years in the SS genotype. Neither gender nor the presence of systemic manifestations was predictive for the prevalence or age of onset of retinopathy. INTERPRETATION Screening for retinopathy may begin at age 9 years for SC genotype patients and at age 13 years for SS and SB-Thalassemia genotype patients. Serial examinations may be done biennially for eyes with normal findings. Patients with an abnormal examination should undergo fluorescein angiography and be followed as necessary.

Canadian Ophthalmological Society evidence-based clinical practice guidelines for the management of diabetic retinopathy

The objective of this document is to provide guidance to Canadian ophthalmologists regarding screening and diagnosis of diabetic retinopathy (DR), management of diabetes as it pertains specifically to DR, and surgical and nonsurgical approaches to the treatment of DR. These guidelines apply to all Canadians with type 1 or type 2 diabetes of all ethnic origins. Other health professionals involved in the care of people with diabetes may find this document helpful. These guidelines were systematically developed and based on a thorough consideration of the medical literature and clinical experience. These guidelines are not meant or intended to restrict innovation. Guidelines are not intended to provide a “cookbook” approach to medicine or to be a replacement for clinical judgment; rather, they are intended to inform patterns of practice. Adherence to these guidelines will not necessarily produce successful outcomes in every case. Furthermore, these guidelines should not be used as a legal resource, as their general nature cannot provide individualized guidance for all patients in all circumstances. Guidelines are not intended to define or serve as a legal standard of medical care. Standards of medical care are specific to all the facts or circumstances involved in an individual case and can be subject to change as scientific knowledge and technology advance, and as practice patterns evolve. There is no expectation that these guidelines be applied in a research setting. No comment is made on the financial impact of procedures recommended in these guidelines. Ideally, guidelines are flexible tools that are based on the best available scientific evidence and clinical information, reflect the consensus of professionals in the field, and allow physicians to use their individual judgment in managing their patients. These guidelines

Observations on the management of Coats' disease: less is more.

Background: In this article we share our experience of treating various severities of Coats’ disease and focus on optimal therapy for advanced disease. Methods: Retrospective chart review of 10 patients treated with varied techniques including intraocular surgery, cryopexy and/or laser photocoagulation. Results: Nine patients were male. At presentation the average age was 4.6 years (range 21 months–7 years), the average number of retinal quadrants involved with telangiectasia was 2.7 (range 1–4, median 3), eight of the 10 patients had retinal detachment, six of these being total, and all patients had macular involvement with either exudate or fibrosis. Average follow-up was 2.3 years (range 1–4.5 years). The best visual outcomes were observed in patients who presented with less severe disease. For example, the only four patients to maintain ambulatory vision all presented without total retinal detachment, two or fewer quadrants of retinal telangiectasia and a visual acuity better than light perception. No patient developed secondary angle closure glaucoma, and all patients have kept a cosmetically acceptable eye. Conclusion: In this limited series, visual outcomes in the setting of advanced Coats’ disease are largely dependent on disease severity and visual status at the time of presentation. Minimally invasive surgery with vitreous infusion through the pars plana, combined with external drainage of subretinal fluid together with cryotherapy and/or laser photocoagulation is sufficient to effect retinal re-attachment and prevent loss of the eye.