Comparison of breath-guards and face-masks on droplet spread in eye clinics.

INTRODUCTION: COVID-19 has impacted ophthalmic care delivery, with many units closed and several ophthalmologists catching COVID-19. Understanding droplet spread in clinical and training settings is paramount in maintaining productivity, while keeping patients and practitioners safe. OBJECTIVES: We aimed to assess the effectiveness of a breath-guard and a face mask in reducing droplet spread within an eye clinic. METHODS: We performed a randomised trial of droplet spread using a fluorescein-based cough model to assess the efficacy of a 'breath-guard' and 'face-mask' to prevent the spread of droplets. The 'cough' spray was collected on calibrated paper targets. The sheets were photographed under blue light, with an orange filter on the camera; the position and size of the spots was measured with software originally developed for astronomy. We performed 44 randomised coughs; 22 controls with no breath-guard or face-mask, 11 using breath-guard only and 11 with combined breath-guard and face-mask. We compared both the number of droplets detected and the area of drops on paper targets. RESULTS: The average number of droplets in the controls was 19,430 (SE 2691), the breath-guard group 80 (SE 19) droplets (P < 0.001); in the combined In the group the count was 5 (SE 2), a significant drop from shield only (P = 0.008). The mean areas of each target covered by spots for each group were 5.7 ± 0.857% (95% CI), 0.004 ± 0.000104% (95% CI) and 0.001 ± 0.0000627% (95% CI) respectively. CONCLUSION: These results show that the breath-guard alone reduced the droplet count by 99.93%. Combining the breath-guard with a face-mask reduced the droplet count by over 99.98%. Breath-guards are widely used in clinics and this trial demonstrates that breath-guards with face-masks effectively block droplet spray.

Detection of dental fomites using topical fluorescein.

Background Thorough disinfection of dental facilities is of paramount importance during the COVID-19 pandemic. Patients, clinicians, students and nurses can all be infected by aerosols and dental droplets bearing COVID-19. However, droplets are transparent and often microscopic, so are difficult to detect in clinical practice.Methods To better understand the spread of dental droplets, we stained the dental irrigant with fluorescein and performed a series of procedures on a dental manikin. We then viewed droplets and fomite spread around the dental chair, with and without an ultraviolet (UV) light.Results Observations without the UV light showed minimal or no fluid spread. However, using UV light, we detected fluorescein on the dentist, chairs and the handpiece, as well as splatter on the floor and on the instrument tray. This was of educational value to the staff, who were reminded how far droplets had spread.Conclusion Fluorescein facilitates the detection of droplet spread and helps clinical staff to see high-risk areas that require in-depth cleaning. As clinical grade fluorescein is cheap and widely available, this technique may be useful for dental practices to train staff in the thorough decontamination of the clinical environment.

The use of aerosol generating procedures (AGPs) during the COVID-19 pandemic in the diagnosis of lung cancer: a narrative review.

OBJECTIVE: In this article we discuss the current evidence for these concerns and highlight where further work is required to understand the risk from these procedures and how it can be mitigated for. BACKGROUND: The COVID-19 (coronavirus-19 or SARS-CoV-2) pandemic has impacted on many aspects of patient care both for those with the virus and those with other illnesses. Of particular concern has been the risk to staff and patients from the spread of the virus in health care settings. This has led to changes in guidelines and practice in community and hospital settings that has implications on patient diagnostic pathways in lung cancer, with a specific emphasis on aerosol generating procedures (AGPs). METHODS: A literature search was carried out and 44 abstracts were initially found. Given the novel status of COVID-19, we included severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS) in our search. Five papers were selected for further analysis. An additional paper was highlighted during our research and therefore included in our review. CONCLUSIONS: The papers selected assessed the risk of transmission during AGPs. The six articles selected assessed the risk of aerosol transmission during various AGPs (bronchoscopy, pleural procedures and pulmonary function tests) and each found that the risk of viral transmission via aerosol was low. As mentioned above, at the time the paper was written, there was a paucity of evidence regarding AGPs in the era of COVID-19. There is emerging evidence that our understanding of these procedures may be outdated and the risk of transmission maybe lower than previously anticipated. However, we need further reliable evidence to change practice going forward.

Retinal Displacement Following Pneumatic Retinopexy vs Pars Plana Vitrectomy for Rhegmatogenous Retinal Detachment.

Importance: Retinal displacement following rhegmatogenous retinal detachment repair may have consequences for visual function. It is important to know whether surgical technique is associated with risk of displacement. Objective: To compare retinal displacement following rhegmatogenous retinal detachment repair with pneumatic retinopexy (PR) vs pars plana vitrectomy (PPV). Interventions or Exposures: Fundus autofluorescence images were assessed by graders masked to surgical technique. Design, Setting, and Participants: A multicenter retrospective consecutive case series in Canada and the UK. A total of 238 patients (238 eyes) with rhegmatogenous retinal detachments treated with PR or PPV who underwent fundus autofluorescence imaging from November 11, 2017, to March 22, 2019, were included. Main Outcomes and Measures: Proportion of patients with retinal displacement detected by retinal vessel printings on fundus autofluorescence imaging in PR vs PPV. Results: Of the 238 patients included in the study, 144 were men (60.5%) and 94 were women (39.5%); mean (SD) age was 62.0 (11.0) years. Of the 238 eyes included in this study, 114 underwent PR (47.9%) and 124 underwent PPV (52.1%) as the final procedure to achieve reattachment. Median time from surgical procedure to fundus autofluorescence imaging was 3 months (interquartile range, 1-5 months). Baseline characteristics in both groups were similar. The proportion of eyes with retinal vessel printing on fundus autofluorescence was 7.0% for PR (8 of 114) and 44.4% for PPV (55 of 124) (37.4% difference; 95% CI, 27.4%-47.3%; P < .001). Analysis based on the initial procedure found that 42.4% (42 of 99) of the eyes in the PPV group vs 15.1% (21 of 139) of the eyes in the PR group (including 13 PR failures with subsequent PPV) had displacement (27.3% difference; 95% CI, 15.9%-38.7%; P < .001). Among eyes with displacement in the macula, the mean (SD) displacement was 0.137 (0.086) mm (n = 6) for PR vs 0.297 (0.283) mm (n = 52) for PPV (0.160-mm difference; 95% CI, 0.057-0.263 mm; P = .006). Mean postoperative logMAR visual acuity was 0.31 (0.32) (n = 134) (Snellen equivalent 20/40) in eyes that initially underwent PR and 0.56 (0.42) (n = 84) (Snellen equivalent 20/72) in eyes that had PPV (-0.25 difference; 95% CI, -0.14 to -0.35; P < .001). Among eyes with displacement, mean postoperative logMAR visual acuity was 0.42 (0.42) (n = 20) (Snellen equivalent 20/52) in those that initially underwent PR and 0.66 (0.47) (n = 33) (Snellen equivalent 20/91) in those that initially underwent PPV (-0.24 difference; 95% CI, -0.48 to 0.01; P = .07). Conclusions and Relevance: These findings suggest that retinal displacement occurs more frequently and is more severe with PPV vs PR when considering the initial and final procedure used to achieve retinal reattachment. Recognizing the importance of anatomic integrity by assessing retinal displacement following reattachment may lead to refinements in vitreoretinal surgery techniques.

Macular pseudohaemorrhage secondary to Allen Dot artefact.

A 34-year-old highly myopic (-11.00 D) woman presented to eye clinic with a 3 day history of right eye paracentral blurring. Visual acuities were 6/6 bilaterally. Clinical examination was normal. Fundus photography showed the classic appearance of a macular haemorrhage. This is a recognised complication of high myopia and would have accounted for the patient's symptoms. However, further photography showed that the haemorrhage seemed to 'jump' around the fundus and was even present in the fellow eye. The apparent haemorrhage was revealed to be an imaging artefact. The 'Allen Dot' is a 6 mm black mask incorporated into retinal cameras to reduce reflection. Rarely, in highly myopic eyes, optical artefact can result. To the best of our knowledge, we are the first in the literature to report artefacts from the Allen Dot masquerading as ophthalmic disease. This case re-iterates the importance of clinical examination, especially in high myopes, given the current trend towards virtual clinics.

Changes in day 1 post-operative intraocular pressure following sutureless 23-gauge and conventional 20-gauge pars plana vitrectomy.

BACKGROUND/AIMS: The benefits associated with transconjunctival sutureless vitrectomy techniques are continuing to be defined. The purpose of this study was to compare the incidence of extreme changes in day 1 intraocular pressure (IOP) following 23-gauge sutureless vitrectomy compared with conventional 20-gauge vitrectomy. METHODS: Fifty consecutive 23-gauge and 50 consecutive 20-gauge cases were included; eyes with a history of previous vitreoretinal surgery were excluded. 23-gauge surgery was completed with passive fluid air exchange where no long acting tamponade was indicated. The surgery remained sutureless unless a leak was visible at the end of the procedure. Data were collected by retrospective case note review. Statistical analysis was carried out using Fisher's exact and chi-square tests. RESULTS: Twenty-two percent (11/50) of 23-gauge vitrectomies required suturing of one or more ports. On the first post-operative day hypotony (IOP<5mmHg) occurred in 1/50 eyes in the 20- and 23-gauge groups. Raised pressure (IOP>21mmHg) occurred in 30% (15/50) of eyes in the 20-gauge group and 8% (4/50) of eyes in the 23-gauge group; IOP>30mmHg only occurred in the 20-gauge group (3/50). CONCLUSION: Fluid air exchange following 23-gauge vitrectomy is associated with very low risk of day 1 hypotony. This predominantly sutureless technique appears to reduce the incidence and magnitude of early post-operative IOP elevation compared with conventional 20-gauge vitrectomy.

The ring sign in patients with pigment epithelial detachments.

Four patients with pigment epithelial detachment due to age-related macular degeneration underwent clinical examination and optical coherence tomography (OCT) scan. A ring-shaped pattern on the fast retinal thickness maps of the OCT was observed for all of these patients with little central retinal thickness but increasing retinal thickness at the edge of the pigment epithelial detachment. The authors have coined the term "ring sign" to describe this pattern typically seen on the OCT scan in patients with pigment epithelial detachment with or without underlying choroidal neovascularization.

A randomized comparison of parecoxib/valdecoxib and placebo for the prevention of cystoid macular edema after scleral buckling surgery.

AIMS: To assess the impact of valdecoxib on the incidence of macular edema, after scleral buckling surgery. METHODS: Prospective randomized double masked placebo controlled study. Patients undergoing scleral buckle surgery over 18 months were recruited and randomized to receive either oral valdecoxib or placebo. Patients also received two doses of either parecoxib (pro-drug of valdecoxib) intravenously 40 mg 6 hourly day one postoperative or identical placebo injection Patients underwent retinal examination, optical coherence tomography and retinal thickness analyzer scan of the macula preoperatively, and at 2 and 6 weeks postoperatively. Outcome measures were the incidence of macular edema, retinal thickness, visual acuity, contrast sensitivity and presence of persistent subretinal fluid. RESULTS: Interim analysis was performed with 116 patients were recruited, 58 to each treatment arm. The incidence of macular edema in all patients was 5% at visit 1 and 2.2% at visit 2 postoperatively. This incidence was much lower than the expected incidence used in the power calculation to determine study size. It was therefore apparent that a much larger study population would be required to test for an effect and that this was not achievable within the study time period. The study was therefore terminated early. There was no evidence of a difference between COX 2 inhibitor and placebo groups in the incidence of edema, retinal thickness or visual outcome. The presence of residual subretinal fluid at the macula was significantly reduced by COX 2 inhibitor treatment. CONCLUSIONS: The rate of cystoid macular edema after scleral buckling surgery is low and is not influenced by prophylactic use of valdecoxib. The rate of residual subretinal fluid was reduced by COX 2 inhibitor treatment. Enhanced antiinflammatory therapy has the potential to improve outcomes in scleral buckling surgery.

Diabetes and the tortuosity of vessels of the bulbar conjunctiva.

OBJECTIVES: Diabetes is associated with loss of capillaries and macrovessel dilation in the conjunctiva, similar to well-known vessel changes in the retina. However, little is known about the effect of diabetes on the tortuosity of vessels of the conjunctiva. The authors examined the tortuosity of conjunctival vessels in participants with and without diabetes. DESIGN: Case-control study. PARTICIPANTS AND CONTROLS: Fifty-three patients with diabetes (17 with type 1 diabetes, 36 with type 2 diabetes) and 60 controls (all aged 20-94 years). METHODS: Digital red-free images of conjunctivae were analyzed using an automated computer algorithm to identify vessel axes and to quantify vessel tortuosity. Differences in vessel tortuosity were adjusted for age, gender, blood pressure, and smoking status. MAIN OUTCOME MEASURES: Tortuosity was expressed in units of curve energy (the square of the radian angular change between subsequent locations identified by the algorithm, standardized by vessel length). RESULTS: A longer duration of diabetes was associated with a reduction in overall vessel tortuosity (-2.8%; 95% confidence interval [CI], -4.3% to -1.3% per decade). This inverse association was driven by changes in larger vessels (40 microm in width or more), whereas increased tortuosity was observed in capillary sized vessels (<25 microm, 4.0%; 95% CI, -0.2% to 8.2% per decade). Compared with controls, those with type 1 diabetes (median duration of disease, 26 years) showed a 17.9% increase (95% CI, 4.7% to -31.0%) in capillary tortuosity. Conversely, those with type 1 diabetes showed a 7% decrease (95% CI, -11.8% to -2.3%) in tortuosity among vessels 40 to 80 microm or less in size and a 26.8% decrease (95% CI, -66.2% to 12.7%) in the fewer number of vessels more than 80 microm in size compared with controls. Similar, but smaller differences were seen in those with type 2 diabetes with shorter duration of diabetes (median, 7 years). CONCLUSIONS: Macrovessel dilation associated with diabetes may result in vessel engorgement and straightening, especially among those with longer durations of disease. Increased tortuosity associated with diabetes among conjunctival capillaries mirrors established vessel changes observed in the retina. Conjunctival angiopathy associated with diabetes may contribute to susceptibility to anterior eye disease among patients with diabetes.

Can optical coherence tomography predict the outcome of laser photocoagulation for diabetic macular edema?

BACKGROUND AND OBJECTIVE: To assess the outcome of laser photocoagulation in patients with diabetic macular edema. PATIENTS AND METHODS: Forty-seven patients (51 eyes) with clinically significant macular edema (CSME) undergoing grid laser photocoagulation were included. Clinical examination and optical coherence tomography (OCT) were performed at baseline and 3 to 4 months after treatment. The central foveal thickness, mean inner macular thickness (average retinal thickness in fovea and inner macular circle), and mean macular thickness were calculated. Based on the greatest OCT thickness at baseline, patients were grouped according to mild (< 300 microm; Group 1), moderate (300 to 399 microm; Group 2), and severe (> or = 400 microm; Group 3) macular edema. RESULTS: Group 2 showed significant reductions in central foveal thickness (23 microm, P = .02), mean inner macular thickness (18 microm, P = .02), and mean macular thickness (9 microm, P = .04) with slight improvement in visual acuity. Groups 1 and 3 did not show any significant change in macular thickness values and there was a statistically insignificant worsening of visual acuity in these groups. CONCLUSIONS: Patients with moderate macular thickening of 300 to 400 microm benefit most from laser treatment. OCT may help in choosing the appropriate treatment for CSME based on the degree of macular thickening. Long-term studies are warranted to confirm these findings.

Combined phacovitrectomy for macular hole: long-term results.

BACKGROUND AND OBJECTIVE: To present the long-term results of patients undergoing combined phacovitrectomy surgery for idiopathic macular hole at a single center. PATIENTS AND METHODS: A retrospective review of the records for 57 eyes of 53 consecutive patients who underwent combined phacovitrectomy for idiopathic macular hole during an 18-month period was completed at the Southampton Eye Unit. RESULTS: In 45 of 57 eyes (78.9%), the macular hole closed after one surgical procedure. Forty-seven patients had a follow-up period of more than 12 months (mean = 22.1 months). In this group, the mean visual acuity (standard deviation) improved by 0.37 (+/- 0.46) logarithm of the minimum angle of resolution units. Thirty-two (68%) cases had improved visual acuity of 2 or more Snellen lines. Hole closure rate at the final follow-up examination was 87.2%. CONCLUSION: Combining phacoemulsification and vitrectomy for an idiopathic macular hole has many benefits. It is a safe procedure and produces long-term results that are comparable to previously published series.

Vascular response of the bulbar conjunctiva to diabetes and elevated blood pressure.

OBJECTIVE: Retinovascular changes associated with diabetes have been clearly documented; changes in vessels of the conjunctiva are less well described. We examined changes in conjunctival vessel morphologic features in participants with and without diabetes. DESIGN: Case-control study. PARTICIPANTS AND CONTROLS: Fifty-three patients with diabetes (17 with type 1 diabetes, 36 with type 2 diabetes) and 60 controls (all aged 20-94 years). METHODS: Digital red-free conjunctival images were captured and an automated computer algorithm was used to derive indices that describe the morphologic features of vessels of the conjunctiva. Percentage differences in vessel indices were adjusted for age, gender, blood pressure, and smoking status. MAIN OUTCOME MEASURES: Mean vessel diameter (micrometers) and vessel density (square millimeters of vessel per square centimeter of bulbar conjunctiva). RESULTS: A strong positive association between the duration of diabetes and overall mean vessel width was observed (P<0.001), resulting from changes in larger vessels (>80 mum in width). Conversely, the duration of diabetes showed a strong inverse association with vessel area (P<0.001) that appeared to be driven by the trend observed in smaller vessels (<40 mum in width). A 25% reduction (95% confidence interval [CI], -35% to -13%; P<0.001) in vessel density in those with type 1 diabetes and a 14% reduction (95% CI, -24% to -3%; P = 0.016) in those with type 2 diabetes, compared with controls, was observed. Mean vessel widths were 11% (95% CI, 4%-17%; P = 0.001) wider in type 1 and 5% (95% CI, 0%-10%; P = 0.073) wider in those with type 2 diabetes compared with controls. The difference in magnitude of effect for type 1 and type 2 diabetes compared with controls was explained by duration of diabetes. Grade of diabetic retinopathy and elevated blood pressure showed similar but less strong associations with vessel indices. CONCLUSIONS: Loss of capillaries and macrovessel dilation in the conjunctiva associated with diabetes compares with well-known vessel changes in the retina. Associations between morphologic changes in the conjunctiva and elevated blood pressure were similar but less strong; this may show that diabetic angiopathy predominates in those with both diabetes and elevated blood pressure.

Sudden visual loss after removal of silicone oil.

PURPOSE: Removal of silicone oil after vitreoretinal surgery reduces potential complications of glaucoma and cataract and improves visual function in 30% of patients. We report the clinical findings of a series of patients who experienced unexpected and permanent visual loss after removal of silicone oil. METHODS: Seven patients with visual loss after removal of silicon oil were investigated with best-corrected Snellen visual acuity (BCVA) assessment, fundus biomicroscopy, fluorescein angiography, optical coherence tomography, and electrophysiologic examination. RESULTS: Six men and one woman (average age, 42.8 years.) presented with profound BCVA loss, averaging 4.7 Snellen lines (SD 1.4), after silicon oil removal. No other complications associated with oil removal were noted. The retina remained attached in all cases, no patient developed cystoid macular edema or epiretinal membrane, and optical coherence tomographic and fluorescein angiographic findings remained normal. Electrodiagnostic testing showed a range of abnormalities, with the majority of patients showing severe macular dysfunction. CONCLUSIONS: We describe a new phenomenon of unexpected visual loss after oil removal in patients with good visual potential. The pathogenesis remains obscure.

Screening for sight-threatening diabetic retinopathy: comparison of fundus photography with automated color contrast threshold test.

PURPOSE: To compare tritan contrast threshold (TCT) with fundus photography in screening for sight-threatening diabetic retinopathy (STDR), before significant visual loss. DESIGN: Prospective, comparative study. METHODS: A total of 510 consenting diabetic patients attending a hospital-based photographic screening clinic were recruited over a 2-year period. Exclusion criteria included visual acuity of worse than 6/9, previous photocoagulation, and a history of previous eye disease known to affect color vision. The automated TCT test was performed using a computerized cathode ray tube-based technique. Retinal photography was performed using a Polaroid mydriatic fundus camera with a 45 degrees field. Grading of diabetic retinopathy was carried out by an ophthalmologist using slit-lamp biomicroscopy and a 78-diopters lens. Assessments of sensitivity, specificity, and predictive values for both fundus photography and the TCT test were made. RESULTS: Both the fundus photography and TCT test correlated significantly with the presence of STDR (P <.0001, chi(2) test). The TCT test yielded a sensitivity of 94% (95% confidence interval [CI], 73%- 100%) and a specificity of 95% (95% CI, 92%- 96%) for detection of STDR compared with a sensitivity of 88% (95% CI, 66%-97%) and a specificity of 95% (95% CI, 93%-97%) with fundus photography. Combined modality improved overall screening performance. CONCLUSION: The TCT assessment is an effective and clinically viable technique, in comparison with fundus photography, to screen for STDR among a diabetic population. Additionally, our results also showed that combining the TCT test with fundus photography greatly increases the performance of screening for STDR.

Large spot endolaser for retinal photocoagulation and transvitreal thermotherapy.

BACKGROUND AND OBJECTIVE: Diode laser transpupillary thermotherapy can be used for the treatment and choroidal tumors. A large spot endolaser probe was developed for endophotocoagulation and transvitreal thermotherapy. The aim of this study was to assess the probe's clinical performance for photocoagulation and transvitreal thermotherapy combined with macular elevation. MATERIALS AND METHODS: Endolaser with a divergent beam giving a 3 mm spot size on the retina was developed. Vitrectomy was performed on ten eyes of five Dutch Belted rabbits. Threshold for photocoagulation was determined for the diode (810 nm) laser in four eyes. In another six eyes, the retina was detached with balanced salt solution prior to laser irradiation. The tissue effects were monitored clinically and with photography and microscopy. RESULTS: Threshold photocoagulation was induced with 150 mW power, for 1 minute, in attached retina. Following retinal detachment, no coagulation occurred at 200 mW (suprathreshold) power for 1 minute. CONCLUSIONS: A large spot endolaser probe may be useful for endophotocoagulation. It generates more gradual photocoagulation than standard endolaser probes, giving a more controllable reaction over a larger area. This may be useful for treatment of large areas of the retina when treating retinal detachments or ischemic retinopathies. When detached retina was irradiated, no retinal damage occurred at suprathreshold power. This development may allow for intraoperative transvitreal thermotherapy of choroidal neovascularization while protecting the retina with intentional intraoperative detachment of the retina.