Factors influencing the reliability of measurements in eyes with full-thickness macular holes: are we measuring incorrectly?

PURPOSE: The calliper function is used for manual measurements of full thickness macular holes (FTMHs). We aimed to investigate whether a reproducible difference could be detected beyond interobserver variability between two commonly used manufacturers in their manual calliper facility in spectral domain optical coherence tomography (OCT) for metrics related to FTMH. METHODS: This is a non-interventional, retrospective, observational study. Two independent observers examined 8 eyes (16 OCT) scans and 128 measurements (minimal linear diameter (MLD), basal diameter and hole height on both sides) of FTMHs, taken on Heidelberg Spectralis and Topcon Triton (OCT machines). The interobserver agreement and OCT machine agreement of measurements were analysed by Bland-Altman plots and intraclass correlation coefficient (ICC) analysis. Spectralis and Triton had 125 µm and 50 µm horizontal b-scan spacing, respectively. RESULTS: Overall, we report high absolute agreement in interobserver (ICC 0.991 (95% CI 0.985 to 0.995, p<0.001)) and OCT machine (ICC 0.993 (95% CI 0.987 to 0.996, p<0.001)) variability. Lower horizontal resolution in Triton compared with Spectralis leads to interobserver variability, in smaller horizontal measurements. Lower horizontal scanning density in Spectralis lead to relatively large interobserver variation if different reference scans were chosen, and consistently smaller MLD measurements than Triton. Vertical measurements without 1:1 scaling lead to inaccurate exaggerated oblique vertical measurements. Calliper function appears otherwise identically calibrated. CONCLUSIONS: We report excellent interobserver and OCT machine agreement in measurements. However, the paper shows several factors that could influence the reliability of measurements acquired in eyes with FTMHs, such as the dimension of the hole as well as different image resolution, density scanning protocols or vertical scaling of the OCT machines viewing platform.

Novel Method to Measure Volumes of Retinal Specific Entities.

Objectives: The aim of this study is to describe and validate an optical-coherence-tomography (OCT)-based method to easily calculate specific volumes, addressing the limitations of current OCT software in automating volumetric analysis for specific entities in retinal pathologies. Methods: After manually drawing the specific entity on linear OCT scans using the calliper function and automated measurement of its area, the following formula was used for volumetric calculation: Volume [mm3] = ∑area [mm2] × OCT-scan distance [mm]. Retinal volume (RV) was measured by two independent observers in eyes with a normal foveal profile (NFP) and was compared with the automated measurements performed by the OCT software (Engineering GmbH, Heidelberg, Germany); the same process was repeated for the volume of the foveal cavity (FC) or foveoschisis (FS) in eyes with lamellar macular holes (LMHs). Power calculations were conducted to ensure adequate sample size. The measurements were re-acquired after six weeks. Intra- and inter-observer variability as well as comparison to automated RV calculations were analysed. Results: This study included a total of 62 eyes divided into two groups: the NFP (30 eyes) and LMH (32 eyes) groups. The Bland-Altman plots showed a high degree of agreement in both groups for inter-observer and intra-observer agreement. In addition, in the NFP group, a high degree of agreement was demonstrated between human observers and the OCT software (Spectralis). Conclusions: An easy, reliable, and widely applicable method to calculate volumes is described and validated in this paper, showing excellent inter- and intra-observer agreement, which can be applied to any entity requiring a specific study in the context of retinal pathologies.

Dislocated 4-haptic intraocular lens rescue with Gore-tex suture scleral re-fixation.

BACKGROUND: Dislocated IOL exchange conventionally involves manipulation within the anterior chamber which risks secondary injury to anterior chamber structures. We describe and evaluate a 4-haptic IOL rescue technique that avoids entering the anterior chamber and thus minimizes post operative inflammation, astigmatism and recovery time relative to conventional IOL explantation and replacement techniques. METHODS: Retrospective, non-randomized, interventional study of all patients undergoing 4-haptic IOL rescue performed by two independent vitreoretinal surgeons at a single UK centre over two years. SURGICAL TECHNIQUE: A limited peritomy is performed with four 25-gauge scleral ports placed to enable use of two forceps, an infusion and a chandelier. A further four 27-gauge sclerotomies are symmetrically placed on the nasal and temporal sclera at 3 mm from the limbus with a 5 mm vertical separation on either side. A pars plana vitrectomy is performed followed by chandelier illuminated, bimanual cleaning of the dislocated IOL using 27-gauge serrated forceps. Gore-tex sutures are threaded through the IOL islets within the vitreous cavity and externalized through the sclerotomies for scleral re-fixation followed by conjunctival closure. RESULTS: Seven patients underwent IOL recycling with Gore-Tex suture scleral re-fixation. All procedures were successful in repositioning the IOLs, with all patients satisfied with post-operative outcome. Mean (standard deviation) time to IOL dislocation was 13 (3) years. Median visual acuity significantly improved post-operatively from 0.85 logMAR (Interquartile Range [IQR]: 0.2-2.1) to 0.07 (0.02-0.60) logMAR (p = 0.02). No significant post-operative complications were noted apart from persistent cystoid macular oedema in one patient non-compliant with post-operative treatment. CONCLUSIONS: Transscleral refixation using Gore-Tex suture is an effective, safe and practical approach in the management of dislocated 4-piece IOLs.

Volumetric Biomarkers of Visual Outcome after Surgical Repair in Lamellar Macular Holes.

BACKGROUND: We investigate novel OCT parameters, based on the volumetric analysis of lamellar macular holes (LMHs), as prognostic indicators for visual outcomes after surgery. METHODS: LMHs were divided into degenerative LMHs (D-LMHs) and ERM-foveoschisis (ERM-FS). Pre-operative clinical, OCT linear and volumetric parameters were collected. Volumes were obtained using the OCT automatic segmentation, such as central retinal volume (CRV) and outer nuclear layer (ONL) volume, or using a novel method to calculate volumes of specific LMH entities like epiretinal proliferation (ERP), foveal cavity (FC) in D-LMH and schitic volume (SV) in ERM-FS. Univariate and multivariate linear regression analysis evaluated the factors predictive for post-operative best-corrected visual acuity (BCVA). RESULTS: We included 31 eyes of 31 patients (14 D-LMH,17 ERM-FS). A pre-operative BCVA ≤ 0.48 logMAR was a predictor for achieving ≤0.30 logMAR at final follow-up. A lower pre-operative BCVA (p = 0.008) and the presence of ERP (p = 0.002) were associated with worse visual outcomes post-surgery. Moreover, novel pre-operative OCT parameters significantly associated with worse post-operative BCVA, such as increased FC volume (p = 0.032) and lower CRV (p = 0.034) in the D-LMH subtype and lower CRV (p < 0.001) and ERP volume (p < 0.001), higher SV (p < 0.001) and foveal ONL volume (p < 0.001) in the ERM-FS subtype. CONCLUSIONS: Novel volumetric OCT parameters can be prognostic indicators of visual outcome following surgery in LMHs.

SF 6 COMPARED WITH C 2 F 6 FOR INFERIOR RHEGMATOGENOUS RETINAL REPAIR : The Manchester Pseudophakic Retinal Detachment Study.

PURPOSE: To compare SF 6 relative with C 2 F 6 in the anatomical and functional outcomes following pars plana vitrectomy for uncomplicated primary pseudophakic rhegmatogenous retinal detachment with inferior causative breaks. METHODS: This is a retrospective, comparative study on eyes with pseudophakic rhegmatogenous retinal detachment with inferior causative breaks that had small-gauge pars plana vitrectomy repair using SF 6 and C 2 F 6 tamponade between 2011 and 2020 at a tertiary centre in the United Kingdom. Primary outcome was single surgery anatomical success, and the secondary outcome was best-corrected visual acuity. Propensity score matching, using preoperative findings as covariates to account for relevant confounders, was performed. RESULTS: From 162 pseudophakic rhegmatogenous retinal detachment eyes with inferior causative breaks, the median (interquartile range) follow-up was 82 (52-182) days. The single surgery anatomical success was 156 (96.3%) overall: 47 of 47 (100.0%) and 109 of 115 (94.8%) in the SF 6 and C 2 F 6 groups, respectively ( P = 0.182). Relative to the SF 6 group, the C 2 F 6 group had a higher mean number of tears (SF 6 : 3.1[2.0], C 2 F 6 : 4.5[2.7], P = 0.002) and greater retinal detachment extent (SF 6 : 5.3[2.9], C 2 F 6 : 6.2[2.6] clock hours, P = 0.025). Following propensity score matching analysis, 80 eyes were matched with 40 in each group to homogenize preoperative factors. No significant difference was found in single surgery anatomical success and best-corrected visual acuity between the groups following propensity score matching. CONCLUSION: Primary pars plana vitrectomy with gas tamponade leads to a high single surgery anatomical success rate in uncomplicated pseudophakic rhegmatogenous retinal detachment with inferior causative breaks with no additional benefit associated with long-acting tamponade when comparing C 2 F 6 with SF 6 .

THE LONG-TERM RECOVERY OF VISION IN PSEUDOPHAKIC MACULA-OFF RHEGMATOGENOUS RETINAL DETACHMENTS.

PURPOSE: To assess the long-term visual recovery in uncomplicated macula-off pseudophakic rhegmatogenous retinal detachment treated with pars plana vitrectomy and gas tamponade in the absence of other visual comorbidities. METHODS: Single-center retrospective longitudinal study on eyes with macula-off pseudophakic rhegmatogenous retinal detachment successfully treated with pars plana vitrectomy between 2011 and 2020 and with at least 2 follow-ups (FU), first gas-free FU (first-FU) and a final-FU, were included. Patients with subsequent ocular surgery or comorbidities affecting best-corrected visual acuity were excluded. The duration between operation date and final-FU was calculated (total days FU) and split into total days quintiles-1: ≤57, 2: >57 and ≤77, 3: >77 and ≤152, 4: >152 and ≤508, and 5: >508 days. Multivariable regression was performed with logMAR gain between the first and the final-FU as the dependent variable. RESULTS: In 209 eyes, the authors report association with increase of logMAR gain between the first and the final-FU, with reducing clock hours of pseudophakic rhegmatogenous retinal detachment ( P = 0.041) and relative to the total days Quintile 1. Mean (SD) logMAR gain between the first and the final-FU was 0.02 (0.07) in the first quintile, increasing to 0.14 (0.13) ( P < 0.001) by the fifth quintile on multivariable regression. For patients not achieving 0.30 logMAR at the first-FU, this was attained at the final-FU with a sensitivity of 51.9% and specificity of 95.5% at a cut off ≤0.58 logMAR at the first-FU (area under the curve 0.756 [95% confidence interval 0.664-0.848], P < 0.001). CONCLUSION: The authors report a significant time-dependent visual improvement after uncomplicated pars plana vitrectomy with gas tamponade for macula-off pseudophakic rhegmatogenous retinal detachment without visual confounders and provide important quantitative data for counselling patients with macula-off repair.

Global warming impact of fluorinated gases in ophthalmic surgeries at a tertiary eye center in India.

PURPOSE: Global warming is one of the greatest health threats of the 21 st century. The ophthalmic sector contributes to the emission of greenhouse gases, thus altering the natural environment. There is currently no data on global emissions of fluorinated gases in ophthalmic surgery. This retrospective study from 2017 to 2021 aims to report the carbon dioxide (CO 2 ) equivalence of sulfur hexafluoride (SF 6 ), hexafluoroethane (C 2 F 6 ), and octafluoropropane (C 3 F 8 ) at a tertiary eye center. METHODS: Data collected from 1842 surgical procedures that used injections of fluorinated gases were analyzed. Environmental impact (global warming potential over 100 years) was calculated by converting milliliters to grams by using modified ideal gas law at standard temperature and pressure for the canisters and then to their CO 2 equivalence. RESULTS: Though 70% of surgeries used C 3 F 8 , the least greenhouse effect causing fluorinated gas, the total carbon emission was 1.4 metric tons. The most common indication was macular hole surgery (36.86%). CONCLUSION: This study paves a step toward analyzing the problem statement, thus awakening us to contemplate options to make ophthalmic surgeries greener.

Cytokines in Immune-mediated "Non-infectious" Uveitis.

Uveitis is a significant cause of ocular morbidity and accounts for approximately 5 - 10% of visual impairments worldwide, particularly among the working-age population. Infections are the cause of ~ 50% cases of uveitis, but it has been suggested that infection might also be implicated in the pathogenesis of immune-mediated "non-infectious" uveitis. There is growing evidence that cytokines (i.e., interleukins, interferons, etc.) are key mediators of immune-mediated "non-infectious" uveitis. For example, activation of the interleukin-23/interleukin-17 signalling pathway is involved in immune-mediated "non-infectious" uveitis. Studies in animal models have been important in investigating the role of cytokines in uveitis. Recent studies of clinical samples from patients with uveitis have allowed the measurement of a considerable array of cytokines even from very small sample volumes (e.g., aqueous and vitreous humour). The identification of complex patterns of cytokines may contribute to a better understanding of their potential pathogenetic role in uveitis as well as to an improved diagnostic and therapeutic approach to treat these potentially blinding pathologies. This review provides further insights into the putative pathobiological role of cytokines in immune-mediated "non-infectious" uveitis.

Unilateral retinal neovascularization associated with recurrent vitreous hemorrhage in a patient with gyrate atrophy.

BACKGROUND/PURPOSE: To describe the first case of unilateral peripheral retinal neovasularization associated with recurrent vitreous hemorrhage and localised tractional retinal detachment in a patient with gyrate atrophy (GA). METHODS: Interventional case report. RESULTS: A 23-year-old man with confirmed diagnosis of gyrate atrophy presented with vitreous hemorrhage and history of stable peripheral inferior tractional retinal detachment in the left eye. After three months, the vitreous hemorrhage partially reabsorbed and peripheral retinal vascular abnormalities with focal neovascularization were detected with associated tractional retinal detachment and confirmed on fluorescein angiography. Cryotherapy was performed to prevent any further bleeding. Twelve months later, the left eye remained stable and no further vitreous bleeding occurred. CONCLUSIONS: The combination of peripheral retinal neovascularization, localised tractional retinal detachment and recurrent vitreous hemorrhage can be a unilateral complication of gyrate atrophy. In similar cases, cryotherapy may represent a valuable therapeutic option to prevent recurrent bleeding.

The Role of Subretinal Injection in Ophthalmic Surgery: Therapeutic Agent Delivery and Other Indications.

Subretinal injection is performed in vitreoretinal surgery with two main aims, namely, the subretinal delivery of therapeutic agents and subretinal injection of fluid to induce a controlled and localized macular detachment. The growing interest in this technique is mainly related to its suitability to deliver gene therapy in direct contact with target tissues. However, subretinal injection has been also used for the surgical management of submacular hemorrhage through the subretinal delivery of tissue plasminogen activator, and for the repair of full-thickness macular holes, in particular refractory ones. In the light of the increasing importance of this maneuver in vitreoretinal surgery as well as of the lack of a standardized surgical approach, we conducted a comprehensive overview on the current indications for subretinal injection, surgical technique with the available variations, and the potential complications.

Long-Term Safety and Efficacy of Pars Plana Vitrectomy for Uveitis: Experience of a Tertiary Referral Centre in the United Kingdom.

AIM: To evaluate the effectiveness of pars plana vitrectomy (PPV) without macular intervention on uveitis eyes with persistent vitreous inflammation/opacities in terms of visual acuity (VA), intraocular inflammation and macular profile. METHODS: We carried out a single-center retrospective study of patients with uveitic eyes that underwent PPV without intervention on the macula due to persistent vitreous inflammation/opacities. The primary outcome measures were best-corrected visual acuity (BCVA), intraocular inflammation and macular profile at 3, 12 and 24 months after surgery. RESULTS: Twenty-seven eyes of twenty-six patients were analyzed. Overall, 77.8% had an improvement of VA (55% by 0.3 LogMAR or more); 62.5% of patients had no intraocular inflammation, and the number of patients on systemic steroids and second-line immunosuppressives was reduced by 26% at 12 months; 87.5% of patients had resolution of macular oedema at 12 months. CONCLUSION: PPV for persistent vitreous inflammation/opacities is safe and effective, showing beneficial outcomes in terms of improvement of BCVA and the reduction in inflammation.

Expansile gas concentration in primary pseudophakic retinal detachment repair, effect on intraocular pressure and outcomes; the Manchester Pseudophakic Retinal Detachment Study.

PURPOSE: To investigate the effect of isovolumetric and expansile gas tamponade concentrations on single surgery anatomical success (SSAS) and day 1 intraocular pressure (IOPD1) following pars plana vitrectomy (PPV) for mild-moderate complexity primary pseudophakic rhegmatogenous retinal detachment (PRD). METHODS: We conducted a single-centre retrospective continuous and comparative study on eyes that had undergone small-gauge PPV using isovolumetric versus expansile gas for PRD repair between 2011 and 2020 at a single tertiary vitreoretinal centre in UK. We performed propensity score matching (PSM) using preoperative findings as covariates to account for relevant confounders. Significant risk factors such as proliferative vitreoretinopathy C or giant retinal tears were excluded. RESULTS: From 456 eyes, PSM analysis matched 240 eyes with 120 in each group. The median (interquartile range) follow-up was 96 (59 to 218) days. The SSAS was 229/240 (95.8%) overall; 115/120 (95.8%) and 114/120 (95.0%) in isovolumetric and expansile groups, respectively (p = 1.000). Relative to the isovolumetric group, the expansile group had lower proportion of eyes with IOP ≤ 21 mmHg (odds ratio, 95% confidence interval, 0.40 [0.23-0.68], p < 0.001); but significantly higher number of eyes with IOP ≥ 22 mmHg (2.53 [1.48-4.34], p < 0.001), ≥ 25 mmHg (2.77 [1.43-5.33], p < 0.001), ≥ 30 mmHg (2.90 [1.28-6.58], p = 0.006) and ≥ 40 mmHg (p = 0.029, isovolumetric: 0 [0%] vs expansile group: 6 [5%]). There was only one case of hypotony (≤ 5 mmHg) 1/240 (0.4%) which occurred in the expansile group. CONCLUSIONS: Expansile gas concentration does not impact SSAS but is associated with significantly raised IOPD1 with no reduction in hypotony rates following PPV for primary PRD.

Unexplained visual loss in retinal detachment repair: comparing gas, silicone oil and heavy silicone oil by multivariable regression.

PURPOSE: To measure the proportion of unexplained and all causes of visual loss following primary rhegmatogenous-retinal-detachment (RRD) repair, comparing gas tamponade (SF6, C2F6, C3F8), silicone oil (SO, 1000cs and 5000cs) and heavy silicone oil (Densiron). METHODS: Retrospective, continuous, comparative study from 01/1/2017-31/5/2021. All primary RRDs were included after successful removal of SO and Densiron. Primary failures were excluded. Visual loss was defined as reduction of ≥0.30 logMAR units. Multivariable binary-logistic and linear regression models to compare tamponade, and all cases of unexplained visual loss and logMAR gain were performed. Covariates included age, ocular co-morbidities, pre-op vision, macula-status, high-myopia, giant-retinal-tear (GRT), perfluorocarbon-use, combined buckle/PPV, PVR-C, retinectomy, tamponade agent and post-operative lens status. RESULTS: Of 1,012 primary RRDs, we found an incidence of unexplained visual loss in 15/1012 (1.5%, SF6:1/341[0.3%], C2F6:4/338[1.2%], C3F8:2/239[0.8%], Densiron:0/33[0.0%], SO-1000cs:5/43[11.6%] and SO-5000cs:3/18[16.7%]), and visual loss of all causes in 57/1012 (5.6%, SF6:13/341[3.8%], C2F6:14/338[4.1%], C3F8:15/239[6.3%], Densiron:2/33[6.1%], SO-1000cs:9/43[20.9%] and SO-5000cs:4/18[22.2%]). On multivariable binary-logistic regression, we report that macula-on RRD (Odds-Ratio[OR]5.7,95% Confidence-interval[CI]1.2-28.2, p=0.032), GRT (OR35.0,CI 2.0-617.3, p=0.015), combined buckle/PPV (OR37.7,CI 2.0-711.4, p=0.015), SO1000cs (OR86.6,CI 5.6-1,348.0), p=0.001) and 5000cs (OR37.2,CI 1.3-1,101.5, p=0.036) (Reference-tamponade:SF6) were associated with unexplained visual loss. Duration of oil tamponade was not linked to increase in unexplained visual loss (p=0.569). CONCLUSIONS: Correlation between SO in detachment repairs and unexplained visual loss has been established, however incidence with HSO has not been compared to other agents. This study demonstrates that although SO was linked with risk-adjusted increased unexplained visual loss relative to gas tamponade, no such association was found for Densiron, on multivariable analysis.

The impact of 360-laser barricade on outcomes of vitrectomy for pseudophakic retinal detachment; The Manchester Pseudophakic Retinal Detachment Study.

PURPOSE: To investigate the anatomical and functional outcomes and specifically, the effect of 360-degree barrier-laser, in pars plana vitrectomy (PPV) for primary pseudophakic rhegmatogenous retinal detachment (PRD). METHODS: We conducted a single-centre retrospective, continuous and comparative study on eyes that had undergone PPV with focal-retinopexy (laser or cryotherapy) versus 360-laser for PRD repair between 2011-2020 at a single tertiary vitreoretinal centre in the UK. Primary outcomes were single surgery anatomical success (SSAS) rate and final postoperative visual acuity (VA). Multivariable regression covariates for primary re-detachment included age, gender, onset-of-detachment, pre-operative VA, ocular co-morbidities, macula-status, majority inferior (vs superior) PRD, number-of-tears and PRD extent (in clock-hours), 360-laser barricade, and perfluorocarbon liquid (PFCL) use. For VA gain, primary re-detachment was added as a covariate. RESULTS: We included 467 eyes with a mean follow-up of 388 (161) days. The SSAS was 444/467 (95.1%) overall, and 351/370 (94.9%) and 93/97 (95.9%) in focal-retinopexy and 360-laser groups, respectively (p = 0.798). Compared to the focal-retinopexy group, the 360-laser group had significantly worse post-operative VA but similar logMAR gain (p = 0.812). A multivariable binary logistic regression found that only PFCL use was linked with increased primary re-detachment (OR:5.32 [p = 0.048]) and 360-laser did not contribute to increased SSAS. A multivariable linear regression analysis showed that poor logMAR gain was significantly associated with better pre-operative logMAR, ocular co-morbidities, greater PRD extent, use of 360-laser and primary re-detachment. However, when excluding macula-off RD (n = 211), 360-laser was no longer significant (p = 0.088). CONCLUSIONS: Prophylactic 360-laser does not seem to impact on SSAS and functional outcomes following PPV for primary PRD.

PREDICTION OF MACULAR HOLE SIZE PROGRESSION BASED ON BASELINE OPTICAL COHERENCE TOMOGRAPHY FINDINGS.

PURPOSE: To quantify the rate of idiopathic macular hole progression from presentation and identify factors that may influence stratification and urgency for surgical listing based on the initial optical coherence tomography scans. METHODS: The minimal linear diameter (MLD), base diameter (BD), and hole height on nasal and temporal sides of idiopathic macular hole were measured on spectral domain optical coherence tomographies, on initial presentation and just before surgery. Mean hole height, hole height asymmetry (absolute difference between nasal and temporal height), MLD/BD, and MLD change per day (MLD/day) were calculated for each patient. Multivariable linear regression analysis with MLD/day as the dependent variable was performed to identify significant risk factors for MLD progression. Minimal linear diameter was grouped to quintiles: 1: ≤290 µ m, 2: >290 µ m and ≤385 µ m, 3: >385 µ m and ≤490 µ m, 4: >490 µ m and ≤623 µ m, and 5: >623 µ m. RESULTS: In 161 eyes (157 patients), we report significant associations with MLD/day: 1) MLD/BD ( P = 0.039) (i.e., wide BD relative to MLD lead to faster progression of MLD), 2) hole height asymmetry ( P = 0.006) (larger absolute difference between nasal and temporal hole height lead to faster progression), and 3) days between scans ( P < 0.001) (longer duration between scans had reduced MLD/day, indicating more rapid increase initially then plateaux), and relative to MLD Quintile 1, MLD Quintile 3 ( P = 0.002) and MLD Quintile 4 ( P = 0,008), and MLD Quintile 5 ( P < 0.001) all lead to a reduced MLD/day rate on multivariable regression. CONCLUSION: In addition to finding that the previously reported initial smaller MLD is a risk factor for rapid MLD progression, we report two novel findings, large hole height asymmetry and a low MLD/BD (wide base relative to MLD), that represent significant risk factors. These factors should be taken into consideration on presentation to stratify timing of surgery.

The use of fluorinated gases and quantification of carbon emission for common vitreoretinal procedures.

PURPOSE: To report the contribution to carbon dioxide equivalent mass [CO2EM] of various types of VR surgery performed across three tertiary referral centres, according to their indication and fluorinated gas used. We secondarily reported on the difference in tamponade choice, and CO2EM between the different centres. MATERIALS: Retrospective, continuous, comparative multicentre study of all procedures using fluorinated gases between 01/01/17-31/12/20 at the Manchester Royal Eye Hospital and Birmingham and Midland Eye Centre, and between 01/01/19-31/12/2020 at the University Hospitals Coventry and Warwickshire. RESULTS: Across 4877 procedures, the use of fluorinated gases produced 284.2 tonnes (71.2 tonnes annually) CO2EM; an annual consumption of 30,330 l of gasoline. Rhegmatogenous-retinal-detachment (RRD) and macular hole repair had the highest CO2EM by indication, accounting for 191.4 tonnes CO2EM (67.3%) and 28.6 tonnes CO2EM (10.1%); a mean 60.0 kg and 32.0 kg of CO2EM produced per surgery respectively. The use of fluorinated gases and their respective CO2EM contributions were significantly different across all three centres (p < 0.001) for all indications. SF6, despite being used in 1883 procedures (38.6%), contributed to 195.5 tonnes CO2EM (68.8%). Relative to C2F6, procedures using C3F8 and SF6 produced 1.9 and 4.4 times more CO2EM. CONCLUSION: We demonstrated that SF6 causes significantly higher carbon emissions relative to C2F6 and C3F8 with RRD and macular hole repair having the greatest environmental impact. We also reported large variations between different large VR centres in fluorinated gas use, and therefore in carbon emission contributions depending on indications for surgery. Evidence-based protocols might help in making VR surgery "greener".

Sustained impact of COVID-19 on primary retinal detachment repair in a tertiary eye hospital from March to December 2020.

Purpose: To review the sustained effect of COVID-19 on rhegmatogenous retinal detachment (RRD) baseline characteristics and outcomes. Methods: This was a retrospective consecutive case series at the Birmingham and Midlands Eye Centre including patients undergoing primary RRD repair between 23 March and 31 December 2017-2019 (Group 1) and 2020 (Group 2). The deciles of indices of multiple deprivation (IMD) were determined by postcode to group patients into least deprived (IMD1-5) and most deprived (IMD6-10). Results: In total we reviewed 1310 patients, 1003 in Group 1 and 307 in Group 2. Relative to 2017-2019, during the first lockdown, we observed (a) a reduction in the number of patients with RRD, (b) an increase in macula-off detachments, (c) an increase in RRD primary failure, and (d) that the least deprived had proportionately higher primary failure than the most deprived (p = 0.049) with a higher detachment rate than the pre-COVID-19 period (p = 0.010) and increased presentations of macula-off detachment. During the second lockdown, these differences were not observed. Conclusion: The previously observed findings of lower presentation rates of RRD during the beginning of the first lockdown and the decreased number of macula-on RRD were not sustained over a longer period of observation or found to recur after a second national lockdown. Patients from areas with the least socioeconomic deprivation seemed to be more negatively affected by the first lockdown, with later presentation and higher rates of re-detachments compared with the most deprived during the first lockdown. Our findings offer reassurance that patient behaviour and health services had adapted to the pandemic by the second national lockdown. Supplementary Information: The online version of this article (10.1007/s00717-022-00521-0) contains supplementary material, which is available to authorized users.

Evaluating the quality and readability of online information on keratoconus treatment.

OBJECTIVE: This study aims to evaluate the quality and readability of online resources on keratoconus treatment. METHODS: A Google.com search was conducted on August 9, 2020; 32 web sites were selected for analysis. Popularity was assessed by Google and Alexa rank. The quality of web sites was analyzed using the quality criteria for consumer health information (DISCERN) tool, the Journal of the American Medical Association (JAMA) benchmark, and the Health On the Net Code of Conduct Certification (HONcode). The readability of the web sites was assessed using the Fleschwebr hea Reading Ease, the Automated Readability Index, and the Fleschted Readability RESULTS: The JAMA benchmark scores, unlike the DISCERN scores, were correlated with the Google and Alexa rank. One web site (3.1%) met all the JAMA benchmark criteria, and 3 (9.3%) others had HONcode certification. The median DISCERN score was 33 (range, 29.6-43.1; maximum possible, 80). Rnib.org.uk scored the highest at 57 (71.0%). The mean Flesch-Kincaid Reading Ease score (52.9 ± 7.1) corresponded to uk" n DIdifficult to read." Thirty-one web sites (96.8%) had a Flesch-Kincaid Grade higher than the American Medical Association recommendation of sixth grade level. The median Automated Readability Index score was 7 (range, 6.2-7.3). CONCLUSION: The majority of online information currently available on keratoconus treatment is complex and highly variable. Rnib.org.uk is the best currently available source. Clinicians should inform patients on how to assess the credibility of online information and recommend suitable information sources.

"Comparing outcomes of advanced nurse practitioners to ophthalmologists performing posterior YAG capsulotomy, a six-year study of 6308 eyes".

PURPOSE: To primarily report the baseline characteristics and visual acuity (VA) outcomes of advanced nurse practitioners (ANP) compared to ophthalmologists following YAG posterior capsulotomy (YAGPC). We secondarily looked to characterise the risk factors that lead to a repeated YAGPC. METHOD: Retrospective consecutive case series of 6,308 eyes attending the Birmingham and Midlands Eye Centre. RESULTS: ANPs performed 33.1% of YAGPC compared to 66.9% ophthalmologists. Compared to ophthalmologists, ANPs performed YAGPC in lower proportion of patients with ocular co-morbidities (p < 0.001) and had lower proportion of patients requiring further YAGPC compared to ophthalmologists (p < 0.001). Median pre, post-operative and LogMAR gain in VA of 0.48 (IQR 0.30-0.78), 0.18 (IQR 0.10-0.40) and 0.30 (0.08-0.48) LogMAR units, respectively. Multivariate regression showed that ANPs had a significantly lower rate of repeat YAGPC compared to ophthalmologists even when adjusting for age, ethnicity, training grade and ocular co-morbidities. No difference in visual outcomes was found between operator grade and ethnicity on multivariate analysis. CONCLUSION: YAGPC leads to excellent visual outcomes. ANPs can deliver safe and effective YAGPC.