Kelly D. Schweitzer

Myopic shift after combined phacoemulsification and vitrectomy with gas tamponade.

BACKGROUND Combination surgery of vitrectomy and phacoemulsification is a common procedure. The present study was undertaken to determine whether gas tamponade plays a role in the myopic shift that has been found previously after this type of surgery. METHODS The study compared 26 subjects undergoing combined procedures without gas tamponade and 28 subjects undergoing the same combined procedures with gas tamponade. The preoperative anticipated refraction was compared with the postoperative measured refraction. RESULTS The difference (Delta) between the predicted preoperative refraction and the resulting refractive status 2 months postoperatively was significantly different (t = 2.66, df = 48, p < 0.01) in eyes undergoing the combined procedure with gas tamponade (mean Delta = -0.30 D, SD = 0.66) compared with those eyes not receiving gas tamponade (mean Delta = 0.16 D, SD = 0.55). A difference in final refraction between the 2 groups of -0.46 D was found. INTERPRETATION Patients undergoing combined procedures with gas tamponade show a statistically significant myopic shift compared with those patients not receiving gas tamponade. Ophthalmologists performing combined procedures with gas tamponade should be aware of this shift in order to select the appropriate intraocular lens and to secure the best visual outcome postoperatively.

Nerve fibre layer changes in highly myopic eyes by optical coherence tomography.

OBJECTIVE The purpose of this study was to investigate any correlations that may exist between retinal nerve fibre layer (RNFL) thickness and high myopia by optical coherence tomography (OCT). DESIGN Case-control study. PARTICIPANTS Ten patients (20 eyes) with high myopia and 10 control patients (20 eyes) matched for age and sex were recruited from a database search of 1 vitreoretinal practice in Regina, Sask. METHODS The RNFL thickness of 10 highly myopic patients and 10 control patients matched for age and sex from a clinical practice was determined using the Stratus OCT. All 10 highly myopic patients selected for the study had a spherical equivalent of > or = -10.0 D OU and an intraocular pressure <21 mm Hg OU, and failed to display glaucomatous changes such as disc hemorrhages and glaucomatous cupping in either eye. None of the patients included in the study had evidence of concomitant ophthalmic disease and none had had previous refractive surgery. Axial length measurements were done on all patients using the IOL Master. RESULTS The mean (SD) RNFL thicknesses in the control and myopic groups were 108.8 (10.6) microm and 80.0 (18.6) microm, respectively, with t = 6.0 and p < 0.001. A negative correlation -0.712 with p < 0.001 was found between RNFL thickness and axial length. CONCLUSIONS When interpreting the RNFL thickness of highly myopic patients by OCT, careful attention must be given to the inherently thinner RNFL to avoid a false glaucoma diagnosis.

Predicting retinal tears in posterior vitreous detachment

OBJECTIVE The purpose of this study is to determine whether patients with acute posterior vitreous detachment (PVD) who develop delayed retinal tears within the first 6 weeks after initial presentation have predictive characteristics. DESIGN Prospective cohort study. PARTICIPANTS All patients presenting to the Hotel Dieu Hospital Emergency Eye Clinic between September 2008 and July 2009 diagnosed with acute PVD were offered enrollment. METHODS At the initial visit, patients were given the previously validated Queens University Posterior Vitreous Detachment Patient Diary to record their daily symptoms for 6 weeks. Two or 6 weeks later, patients were reexamined in detail, and their diaries were collected and analyzed. Exact logistic regression was used to establish characteristics predictive of delayed retinal tears. RESULTS In our study population of 99 patients, 2 developed delayed retinal tears. One had retinal hemorrhages and the other had a cloud-like floater at initial presentation. Vitreal or retinal hemorrhage, large number of floaters at initial presentation, and high floater frequency at initial presentation indicated a high risk of delayed retinal tear formation, yielding a median unbiased estimated odds ratio of 36.18 with p value 0.009. No other presenting risk factors or symptomatology followed daily over the first 6 weeks after acute PVD were predictive of delayed retinal tear formation. CONCLUSIONS PVD patients with retinal or vitreal hemorrhage, a significant number of floaters or a cloud like appearance to the floaters, or high floater frequency are at higher risk of developing delayed retinal tears.

Oculoleptomeningeal amyloidosis in 3 individuals with the transthyretin variant Tyr69His.

OBJECTIVE To describe 3 cases of oculoleptomeningeal amyloidosis (OLMA). DESIGN Descriptive case series. PARTICIPANTS Three siblings who presented with floaters and decreased visual acuity. METHODS A complete ophthalmologic examination, magnetic resonance imaging, cytological, and genetic studies were carried out in clinical practice. Each sibling was treated by means of pars plana vitrectomy. Vitreous samples stained with Congo Red revealed apple-green birefringence when viewed under polarized light. RESULTS In each case, visual acuity improved greatly after pars plana vitrectomy. A Tyr69His mutation in the transthyretin (TTR) gene was genetically confirmed in 2 of the siblings. CONCLUSIONS This report adds to the literature regarding OLMA and its association with a Tyr69His mutation in the TTR gene. Despite no proven therapy at this time, symptomatic treatment with pars plana vitrectomy appears to be beneficial.

Punctal Plug Retention Rates for the Treatment of Moderate to Severe Dry Eye: A Randomized, Double-Masked, Controlled Clinical Trial

PURPOSE To compare retention rates of Super Flex (Eagle Vision, Memphis, Tennessee, USA; Softplug-Oasis Medical Inc, Glendora, California, USA) vs Parasol (Odyssey Medical, Memphis, Tennessee, USA; Beaver Visitec International, Waltham, Massachusetts, USA) punctal plugs. DESIGN Randomized, double-masked, interventional controlled clinical trial. METHODS Institutional study at Hotel Dieu Hospital (Queens University) of 50 eyes, from patients with moderate to severe dry eye. Each eye from eligible patients was separately randomized to receive Super Flex or Parasol punctal plugs. The main outcome measure was plug retention at 6 months. Secondary outcome measures included objective tests of Schirmer I (mm), tear meniscus height (mm), tear break-up time (s), inferior fluorescein corneal staining (National Eye Institute [NEI] scale), and average lissamine green conjunctival staining (NEI scale). RESULTS Punctal plug retention was significantly different at 6 months (P = .011). Sixty-eight percent of Parasol plugs were retained compared to 32% of Super Flex plugs. Parasol plugs required less frequent artificial tear use at 6 months (P = .024). There was a statistically significant improvement in all secondary outcome measures (Schirmer, tear meniscus height, tear break-up time, fluorescein corneal staining) at 6 months within plug groups except conjunctival staining. There were no additional significant differences between groups and no plug complications reported. CONCLUSIONS Punctal plugs improve symptoms of moderate to severe dry eye; however, retention rates differ significantly. These data will allow us to guide patient decision making for the safe and effective treatment of punctal plugs for moderate to severe dry eye.

Quality of life amongst American vs. Canadian patients with retinal diseases.

Purpose of review To compare health-related quality of life (HRQoL) in American vs. Canadian populations suffering from retinal diseases. Recent findings A search of Medline was conducted according to a strategy that combined the MeSH heading ‘retinal diseases’ with either of ‘quality of life’ as a MeSH or ‘utility’ as a keyword. We included studies of American or Canadian patients using any of the National Eye Institute 25-item visual functioning questionnaire (NEI-VFQ-25), visual function index (VF-14), short form health survey (SF-36), or utility to assess HRQoL. A total of 22 studies with American patients and five with Canadian patients were found. There was no significant HRQoL difference found between the American and Canadian patients for any of the HRQoL instruments (P = 0.14–0.80); however, for all instruments mean HRQoL correlated positively with mean visual acuity in the better-seeing eye (P < 0.001). Summary On the basis of a review of the currently published literature, we were unable to detect significant differences in HRQoL between American and Canadian patients. Further research into the topic is necessary.

Visual function analysis in acute posterior vitreous detachment

OBJECTIVE To determine whether the visual function of patients with posterior vitreous detachment (PVD)changes between the initial visit and a 6-week follow-up visit, and to compare their visual function with that of patients with macular degeneration, cataract, glaucoma, low vision, cytomegalovirus (CMV) retinitis, or diabetic retinopathy and a reference population. DESIGN Prospective cohort study. PARTICIPANTS All patients presenting to the Hotel Dieu Hospital Emergency Eye Clinic between September 2008 and June 2009 who were diagnosed with acute PVD were offered enrollment in the study. METHODS Patients were administered the National Eye Institute Visual Function Questionnaire NEI VFQ-25 at two points in time. The composite scores from the initial and the 6-week visits were compared. The scores were also compared with established normative data and 6 ophthalmologic diagnoses. RESULTS The NEI VFQ-25 composite score for patients with acute PVD (n = 84) at baseline was 93.26 ± 5.59 (mean ± SD). After 6 weeks and a second ocular examination, there was no statistical difference in the composite score of 93.47 ± 6.20 (mean ± SD). (1-sided paired t-test, t = 0.57; P = 0.28). CONCLUSIONS The visual function of patients with acute PVD remains stable over the first 6 weeks after diagnosis. It is significantly higher than that of patients with 6 other ophthalmologic conditions but comparable to that of a normal population.

Practice patterns of Canadian vitreoretinal specialists in diabetic macular edema treatment

OBJECTIVE To establish the practice patterns of Canadian vitreoretinal (VR) specialists in the treatment of diabetic macular edema (DME). DESIGN A survey was mailed, faxed, e-mailed, and published online for access by all Canadian VR specialists. PARTICIPANTS All VR specialists identified from the Canadian Ophthalmology Society directory and the Canadian Retina and Vitreous Society directory. METHODS A 19-item survey investigating treatment of DME was mailed to all VR specialists. A reminder fax and e-mail was sent with the survey attached. In all correspondence, physicians were given information regarding an available online version of the survey. The survey data was descriptively analyzed with the Statistical Package for the Social Sciences. RESULTS With clinically significant macular edema (CSME) that is either away from the foveal avascular zone (FAZ) or diffuse, the most common first-line treatment option was macular photocoagulation 48 (78.8%) and 33 (54.1%), respectively. For microaneurysms within the FAZ, 33 (54.1%) of respondents chose intravitreal antivascular endothelial growth factor agents as their first-line treatment. In all, 51 respondents (83.6%) felt that vitrectomy played a role in the management of treatment-resistant CSME. Before utilizing intravitreal triamcinolone acetonide (IVT) injections, 34 (55.7%) of respondents did use a topical steroid trial to look for raised intraocular pressure whereas 16 (26.2%) of respondents did not use IVT injections at all. CONCLUSIONS This survey provides valuable practical information on how DME is currently being treated in Canada and may serve as a baseline to assess how these patterns evolve over time.

Design and Validation of a Training Simulator for Laser Capsulotomy, Peripheral Iridotomy, and Retinopexy

BACKGROUND AND OBJECTIVES Ophthalmology trainees commonly learn laser procedures on live patients. A simulator for learning peripheral iridotomy (PI), posterior capsulotomy, and retinopexy may improve patient outcomes. MATERIALS AND METHODS A model eye with artificial tissues was designed. The tissues reacted to laser similarly to human tissues. Inexperienced (n = 6; first- to third-year residents) and experienced (n = 7; fourth- to fifth-year residents and staff) ophthalmic personal were compared on performance of the above laser procedures. RESULTS The inexperienced group required more shots (P = .04) and caused more lens markings (P = .04) during capsulotomy and had more incomplete retinopexy results (P = .04) than the experienced group. The groups did not differ in total shots for PI, average power for retinopexy, or the total time required for any of the procedures. CONCLUSION Our model effectively simulates common ophthalmic laser procedures and is practical for the training of ophthalmology residents. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:56-61.].

Value of subjective visual reduction in patients with acute-onset floaters and/or flashes

OBJECTIVE To quantify the association between subjective visual reduction (SVR) and retinal pathology in patients with acute-onset monocular floaters or flashes, or both. DESIGN, SETTING, AND PARTICIPANTS Prospective cohorts study involving all new patients referred for acute-onset floaters or flashes, or both, to a tertiary care emergency eye clinic in Kingston, Ontario, between July 1, 2011, and June 29, 2012 (n = 333). METHODS All patients were evaluated for the presence of SVR in a standardized fashion, as well as other known risk factors for retina pathology including a family history of retinal tear or retinal detachment, a personal history of retinal tear or detachment, high myopia, and ocular trauma. Our major outcome was urgent retinal pathology, defined as retina pathology requiring a same-day referral to a retina specialist for evaluation, management, or both. RESULTS SVR was strongly associated with retinal pathology (likelihood ratio 7.9, 95% CI 5.2-12.1). CONCLUSIONS Patients with SVR are at increased risk for urgent retinal pathology and should be triaged for urgent ophthalmologic examination.