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.

Resistance of ocular flora to gatifloxacin in patients undergoing intravitreal injections.

OBJECTIVE: To compare gatifloxacin resistance in a population of ophthalmology patients who had received intravitreal injections (IVIs) with prophylactic topical gatifloxacin use to resistance in a similar population of patients who had not received IVI. DESIGN: Nested case-control study. PARTICIPANTS: Fifty eyes of 50 patients who received prior IVI were enrolled, as were 50 control eyes. METHODS: Each patient had a conjunctival swab performed on the study eye, which underwent microbial identification and testing for gatifloxacin resistance using the ellipsoid test to determine a minimum inhibitory concentration (MIC) value for each isolate. The primary outcome was susceptibility to gatifloxacin, as measured by the MIC of each isolate. RESULTS: A total of 111 bacterial isolates were obtained from 60 eyes; the remainder was culture negative. There were no significant differences in bacterial species or culture positivity rate between case and control eyes (50% in cases vs. 66% in controls, p = 0.16). The most common organism was coagulase-negative staphylococcus, comprising 64% of all isolates. Resistance to gatifloxacin was observed in 76% of the bacterial isolates and 38% of patients in the case group, as compared with 3% of bacterial isolates and 4% of patients in the control group, a result that was statistically significant (p = 0.0002 and 0.0008, respectively). The mean gatifloxacin MIC was also significantly higher in the case group. CONCLUSIONS: Topical gatifloxacin prophylaxis in those who receive IVI is associated with an increased rate of gatifloxacin resistance among conjunctival isolates.

Using patient positioning to promote resorption of subretinal fluid in rhegmatogenous retinal detachment before pneumatic retinopexy.

PURPOSE: The purpose of this study was to determine if the volume of subretinal fluid in patients with acute rhegmatogenous retinal detachment may be reduced through patient positioning before pneumatic retinopexy. METHODS: This was a prospective, masked nonrandomized cohort study examining the change in subretinal fluid volume in patients with rhegmatogenous retinal detachment before and after a 1-hour period of specific head positioning, as measured using B-scan ultrasonography. A series of B-scans, each 2 mm apart in the sagittal plane, were acquired for each eye both before and after the positioning period with the patient lying in a supine position. RESULTS: Ten patients with acute unilateral rhegmatogenous retinal detachment were enrolled. All patients experienced a reduction in subretinal fluid volume, from a mean prepositioning volume of 0.89 ± 0.63 mL to a mean postpositioning volume of 0.45 ± 0.43 mL. The mean relative reduction in subretinal fluid measured as a percentage of prepositioning subretinal fluid volume was 55.4% ± 20%, ranging from 35.3% to 93.5%. CONCLUSION: In patients with acute rhegmatogenous retinal detachment that fall within the classic indications for pneumatic retinopexy, significant reduction of subretinal fluid volume may be obtained through a 1-hour period of patient positioning in a retinal break-dependent manner.

Impact of colour in the assessment of potential visual acuity in patients with age-related macular degeneration.

OBJECTIVE: To compare chromatic and achromatic potential visual acuity (PVA) in patients with bilateral low vision caused by age-related macular degeneration (AMD). DESIGN: Prospective, nonrandomized, observational case series. PARTICIPANTS: Fifty-five patients, representing a consecutive series of patients all presenting with bilateral AMD. METHODS: Best-corrected visual acuity of each eye was measured using an Early Treatment in Diabetic Retinopathy Study (ETDRS) chart with appropriate near correction. Included were cases with visual acuity of 0.4 logMAR (20/50) or worse in both eyes. Achromatic and chromatic PVA were measured in each eye using white on black and red on yellow flooding E charts at 50 cm in controlled lighting conditions. RESULTS: One hundred and seven eyes from 55 patients were included in the analysis. Mean achromatic and chromatic PVA were 0.69 ± 0.26 and 0.65 ± 0.22 logMAR, respectively. Overall, patients had a significantly higher chromatic than achromatic PVA, with a median difference of 0.1 logMAR (p<0.05). Patients with ETDRS visual acuity worse than 0.9 logMAR also had a significantly higher chromatic than achromatic PVA, with a median difference of 0.1 logMAR (p<0.05). Patients with ETDRS visual acuity between 0.4 and 0.9 logMAR had a trend toward a higher chromatic than achromatic visual acuity that was not significant, with a median difference of 0.1 logMAR (p = 0.8539). CONCLUSIONS: Patients with low vision caused by AMD can discern smaller targets when a red on yellow colour scheme is used than when using achromatic white on black charts.

Bilateral pseudohypopyon as a presenting feature of recurrent diffuse large B-cell lymphoma.

A 55-year-old man with Gaucher disease and B-cell lymphoma developed a white meniscus along the inferior portion of the anterior chamber of both eyes. In one eye, the meniscus was also temporal, reflecting the fact that he had just been lying on his left side. Aspiration of aqueous fluid confirmed that the meniscus was made up of lymphoma cells, indicating that it was a pseudohypopyon. (A true hypopyon is made up of reactive white blood cells.) Despite intensive chemotherapy, the patient expired within 14 weeks of the discovery of the pseudohypopyon. This is the first report of binocular pseudohypopyon confirmed as lymphomatous by flow cytometric immunophenotyping analysis in a patient with diffuse large B-cell lymphoma.

Indications for penetrating keratoplasty in a tertiary referral centre in Canada, 1996-2004.

BACKGROUND: The leading indications for penetrating keratoplasty (PKP) have changed over recent years. This study examined the leading indications for PKP and their trends, comparing these with recently published data from other studies, including a report from our centre examining indications from 1986 through 1995. METHODS: A retrospective chart review was conducted of all patients who underwent PKP in a single practice at the University Health Network, Toronto Western Hospital, between July 1, 1996, and June 30, 2004. RESULTS: A total of 617 patients underwent 794 PKP operations during the 8-year study period. Sufficient documentation was available to include 777 surgeries from 600 patients in this study. Specific indications for PKP were reported and grouped into 16 categories. The leading indication categories for PKP were regraft (209 cases, 26.9%), pseudophakic bullous keratopathy (PBK) (193 cases, 24.8%), primary corneal endotheliopathies including Fuchs' endothelial dystrophy (101 cases, 13.0%), anterior keratoconus (93 cases, 12.0%), and viral or postviral causes (41 cases, 5.3%). Regraft, keratoconus, and Fuchs' endothelial dystrophy each displayed a nonsignificant decreasing trend from 1996 to 2004, and PBK, herpes simplex virus, and mechanical trauma each displayed a nonsignificant increasing trend (p > 0.05 for all). INTERPRETATION: Regraft was the leading indication for PKP at our centre, followed by PBK; these findings were in agreement with data reported in recent literature. The frequency of regraft had increased since a previous study from our centre (1986-1995), and the frequency of PBK had decreased.

Demographics of corneal transplantation in Canada in 2004.

BACKGROUND: Penetrating keratoplasty (PKP) is the most frequently performed transplant surgery, and one of the most successful, yet no national study on the demographics of corneal transplantation in Canada has been published to date. The objectives of this study were to determine demographics of Canadian corneal transplant surgeons, donor tissue availability and waitlist length for each province, and limiting factors for the number of PKPs performed in Canada. METHODS: An anonymous voluntary survey of all Canadian corneal transplant surgeons was conducted between June and September 2004, with a concurrent voluntary survey of all eye banks in Canada. RESULTS: In 2004, there were 76 corneal transplant surgeons distributed as follows: British Columbia 17.1%, Alberta 11.8%, Saskatchewan 3.9%, Manitoba 7.9%, Ontario 36.8%, Quebec 17.1% and the Atlantic provinces 5.3%. The response rate of the Canadian corneal transplant surgeon survey was 69.7%. On average, each respondent performed 1 (SD 1) PKP/week, 40 (33) PKPs/year, and had a waitlist of 50 (63) patients. The mean wait time from date of referral to initial consultation was 10 (SD 7) weeks and from time of diagnosis to PKP was 51 (32) weeks. The most significant contributing factor to PKP waitlist selected by respondents in all provinces except Ontario was donor tissue shortage (64.7%); Ontario respondents (81.0%) believed that insufficient operating room time was the main factor. Ontario was the only province where all corneal transplant surgeons scheduled PKP electively and where surplus corneal tissue was regularly exported. INTERPRETATION: Recommendations include standardizing the criteria for acceptable donor tissue across all eye banks in Canada to increase efficiency of distribution, introducing and properly implementing mandatory referral and request legislation to increase donor rates, and increasing availability of operating room time for corneal transplant surgeons, especially in Ontario.