Comparability of retinal thickness measurements using different scanning protocols on spectral-domain optical coherence tomography.

Retinal thickness measurements obtained using optical coherence tomography (OCT) play an essential role both in multi-center clinical trials and in normal clinical practice. Different scanning protocols are available on most OCT devices, and it is important to ascertain whether the retinal thickness measurements obtained from these are comparable. This study aimed to compare retinal thickness measurements between raster and radial scanning protocols using spectral-domain OCT (SD-OCT). In a prospective study, 32 healthy subjects were scanned sequentially using raster and radial protocols from a SD-OCT device. For both the raster and radial OCT scans, retinal thicknesses were measured manually subfoveally and at 12 other points at 0.5 mm intervals temporally and nasally on the horizontal OCT B-scan passing through the fovea. The retinal thickness measurements were compared using intraclass correlation (ICC) and Bland-Altman plots. Subfoveal retinal thickness was 227.0 µm when measured on the raster scan and 229.2 µm on the radial scan, with a mean difference of 2.2 µm (P = 0.141).The ICC for agreement was 0.889 (95 % confidence interval 0.818-0.933). Similar results were observed for retinal thickness measurements at all other points, with mean differences ranging from -3.37 to 2.59 µm, and ICC values ranging from 0.837 to 0.972. The retinal thickness measurements obtained by the raster and radial scans of the same SD-OCT device are comparable, with differences of less than 4 µm. This is of relevance when measurements made using different OCT scan protocols are compared.

The Humira in Ocular Inflammations Taper (HOT) Study.

PURPOSE: To assess factors that impact the risk of relapse in patients with noninfectious uveitis (NIU) who undergo adalimumab tapering after achieving remission. DESIGN: Retrospective study. METHODS: In this multicenter study, patients with NIU were treated with adalimumab and subsequently tapered. Patient demographics, type of NIU, onset and duration of disease, the period of inactivity before tapering adalimumab, and the tapering schedule were collected. The primary outcome measures were independent predictors of the rate of uveitis recurrence after adalimumab tapering. RESULTS: Three hundred twenty-eight patients were included (54.6% female) with a mean age of 34.3 years. The mean time between disease onset and initiation of adalimumab therapy was 35.2 ± 70.1 weeks. Adalimumab tapering was commenced after a mean of 100.8 ± 69.7 weeks of inactivity. Recurrence was observed in 39.6% of patients at a mean of 44.7 ± 61.7 weeks. Patients who experienced recurrence were significantly younger than those without recurrence (mean 29.4 years vs 37.5 years, P = .0005), and the rate of recurrence was significantly higher in younger subjects (hazard ratio [HR] = 0.88 per decade of increasing age, P = .01). The lowest rate of recurrence was among Asian subjects. A faster adalimumab taper was associated with an increased recurrence rate (HR = 1.23 per unit increase in speed, P < .0005). Conversely, a more extended period of remission before tapering was associated with a lower rate of recurrence (HR = 0.97 per 10-weeks longer period of inactivity, P = .04). CONCLUSIONS: When tapering adalimumab, factors that should be considered include patient age, race, and duration of disease remission on adalimumab. A slow tapering schedule is advisable.

Incidence of COVID-19 Vaccination-Related Uveitis and Effects of Booster Dose in a Tertiary Uveitis Referral Center.

Background: We report vaccine and booster-related uveitis in Singapore, a country with high vaccination and booster rates to highlight the differences and potential role of prophylactic treatment for sight-threatening infectious uveitis. Methods: Clinical data extracted from the de-identified uveitis database in Singapore National Eye Center. Six patients (eight eyes) developed uveitis within 14 days after undergoing COVID-19 vaccination (primary and/or booster). Results: All patients received two doses of COVID-19 vaccination, and 1.39% (6/431) developed COVID-19 vaccine-related uveitis. Fifty-percent% (3/6) with non-infectious anterior uveitis (NIAU) presented with a non-granulomatous anterior uveitis (AU). The remaining (3/6) presenting with a granulomatous AU were diagnosed with reactivation of cytomegalovirus, varicella-zoster virus and toxoplasma chorioretinitis, respectively. All the patients responded to definitive treatment specific to their diagnosis. The mean visual acuity at presentation was 0.36 ± 0.20 logMAR and improved to 0.75 ± 0.09 (p = 0.009). Mean time from vaccination to uveitis was 9.7 (range: 3-14) days. All patients developed uveitis after second vaccination dose. 16.67% (1/6) patients had a recurrence after the third booster dose. None of the three patients with infectious uveitis developed recurrence but had received maintenance therapy up to or during the booster. Conclusion: Uveitis after COVID-19 vaccination is uncommon. In our series, a higher rate of reactivations of latent infections was seen. With definitive treatment, all cases were self-limited without systemic sequelae. Prophylactic treatment during booster vaccine may prevent reactivation of sight-threatening infections and reduce morbidity although risk-benefits should be considered for individual patients given the low rate of occurrence.

Comparative Study of Long-term Graft Survival Between Penetrating Keratoplasty and Deep Anterior Lamellar Keratoplasty.

PURPOSE: Endothelial failure and immunological graft rejection remain long-term complications leading to late graft failure in penetrating keratoplasty (PK). Deep anterior lamellar keratoplasty (DALK) has emerged as a viable alternative that enables preservation of the host's endothelial cells to eliminate risks of endothelial rejection and failure. The aim of this study was to compare long-term graft survival between PK and DALK. DESIGN: Retrospective clinical cohort study. METHODS: All consecutive primary grafts of DALKs (n = 362) and PKs (n = 307) performed for optical indications in a tertiary eye center from the ongoing, prospective Singapore Corneal Transplant Study. Ten-year graft survival outcomes were compared. Cases in which endothelial pathologies were diagnosed were excluded, as DALK was not performed for such cases. Main outcome measurements were mean graft survival rate. RESULTS: The survival rate for PK was 94.4%, 80.4%, and 72.0% at 1, 5, and 10 years, respectively; and 95.8%, 93.9%, and 93.9% at 1, 5, and 10 years, respectively, for DALK (P = .001). Patients who underwent PK developed more complications of glaucoma (29.3% vs. 11.6%, respectively; P < .001), allograft rejection (16.6% vs. 1.7%, respectively; P < .001), epithelial problems (10.4% vs. 5.5%, respectively; P = .018), and nonimmunological failure (7.8% vs. 1.9%, respectively; P < .001), compared to DALK. Rates of graft failure attributable to rejection (36.7% vs. 5.9%, respectively; P = .015) and endothelial failure (36.7% vs. 5.9%, respectively; P = .015) were lower in DALK. CONCLUSIONS: The 10-year graft survival for primary DALK was superior to that for PK for corneal pathologies with functional endothelium. Primary DALK resulted in fewer post-operative complications and lower rates of graft rejection and failure. This study strengthens the case in favor of performing DALK over PK when possible.

Optimising graft survival in endothelial keratoplasty for endothelial failure secondary to cytomegalovirus endotheliitis.

BACKGROUND: There is limited information regarding Descemet stripping automated endothelial keratoplasty (DSAEK) for endothelial failure secondary to cytomegalovirus (CMV) endotheliitis. Treatment is difficult with high recurrence rates. We describe a case when systemic valganciclovir therapy is directed by aqueous CMV-DNA levels, leading to good graft survival. FINDINGS: A 59-year-old male with bilateral CMV endotheliitis despite antiviral therapy developed endothelial failure and underwent DSAEK. Prior to surgery, aqueous polymerase chain reaction (PCR) for CMV was repeatedly performed, where CMV-positive episodes were treated with systemic valganciclovir. Monthly aqueous analysis was performed until CMV-DNA was undetectable before DSAEK was performed. Post-operative prophylactic systemic valganciclovir treatment was instituted and switched to topical valganciclovir treatment when aqueous samples were negative for CMV. CONCLUSION: Targeted aqueous sampling for CMV-DNA perioperatively guides antiviral therapy and ensures adequacy of treatment, minimising the duration of systemic valganciclovir therapy to reduce adverse effects of long-term treatment.

Effects of low and moderate refractive errors on chromatic pupillometry.

Chromatic pupillometry is an emerging modality in the assessment of retinal and optic nerve disorders. Herein, we evaluate the effect of low and moderate refractive errors on pupillary responses to blue- and red-light stimuli in a healthy older population. This study included 139 participants (≥50 years) grouped by refractive error: moderate myopes (>-6.0D and ≤-3.0D, n = 24), low myopes (>-3.0D and <-0.5D, n = 30), emmetropes (≥-0.5D and ≤0.5D, n = 31) and hyperopes (>0.5D and <6.0D, n = 54). Participants were exposed to logarithmically ramping-up blue (462 nm) and red (638 nm) light stimuli, designed to sequentially activate rods, cones and intrinsically-photosensitive retinal ganglion cells. Pupil size was assessed monocularly using infra-red pupillography. Baseline pupil diameter correlated inversely with spherical equivalent (R = -0.26, P < 0.01), and positively with axial length (R = 0.37, P < 0.01) and anterior chamber depth (R = 0.43, P < 0.01). Baseline-adjusted pupillary constriction amplitudes to blue light did not differ between groups (P = 0.45), while constriction amplitudes to red light were greater in hyperopes compared to emmetropes (P = 0.04) at moderate to bright light intensities (12.25-14.0 Log photons/cm²/s). Our results demonstrate that low and moderate myopia do not alter pupillary responses to ramping-up blue- and red-light stimuli in healthy older individuals. Conversely, pupillary responses to red light should be interpreted cautiously in hyperopic eyes.

Measuring the precise area of peripheral retinal non-perfusion using ultra-widefield imaging and its correlation with the ischaemic index.

OBJECTIVE: To determine the calculated, anatomically correct, area of retinal non-perfusion and total area of visible retina on ultra-widefield fluorescein angiography (UWF FA) in retinal vein occlusion (RVO) and to compare the corrected measures of non-perfusion with the ischaemic index. METHODS: Uncorrected UWF FA images from 32 patients with RVO were graded manually for capillary non-perfusion, which was calculated as a percentage of the total visible retina (uncorrected ischaemic index). The annotated images were converted using novel stereographic projection software to calculate precise areas of non-perfusion in mm(2), which was compared as a percentage of the total area of visible retina ('corrected non-perfusion percentage') with the ischaemic index. RESULTS: The precise areas of peripheral non-perfusion ranged from 0 mm(2) to 365.4 mm(2) (mean 95.1 mm(2)), while the mean total visible retinal area was 697.0 mm(2). The mean corrected non-perfusion percentage was similar to the uncorrected ischaemic index (13.5% vs 14.8%, p=0.239). The corrected non-perfusion percentage correlated with uncorrected ischaemic index (R=0.978, p<0.001), but the difference in non-perfusion percentage between corrected and uncorrected metrics was as high as 14.8%. CONCLUSIONS: Using stereographic projection software, lesion areas on UWF images can be calculated in anatomically correct physical units (mm(2)). Eyes with RVO show large areas of peripheral retinal non-perfusion.

Factors affecting visual outcome of myopic choroidal neovascularization treated with verteporfin photodynamic therapy.

AIM: To evaluate the visual outcomes of choroidal neovascularization (CNV) secondary to pathological myopia and the impact of novel risk factors affecting the final visual outcome. METHODS: Interventional case series of 18 consecutive patients with pathological myopia treated with photodynamic therapy (PDT). Inclusion criteria were spherical equivalent -6D or worse or features of pathological myopia on retinal examination. The main outcome measure was final best-corrected visual acuity (BCVA). RESULTS: Of 18 eyes, 13 (72.2%) avoided moderate visual loss (≥3 lines of LogMAR BCVA) and 5 eyes (27.8%) improved by at least 1 line after 1 year. Patients with LogMAR BCVA ≤0.3 (Snellen equivalent 20/40) at one year were younger than those with BCVA >0.3 (mean age 39.0 vs 61.6 years, P=0.001). A higher proportion of eyes with greatest linear dimension (GLD) of ≤1000µm avoided moderate visual loss (100% vs 50%, P=0.026). Among patients who were treated within 2 weeks of visual symptoms, 88.9% avoided the loss of 3 or more lines compared to 55.6% for those who presented later. The mean improvement in LogMAR BCVA of those with GLD ≤1000µm was +0.12 compared to a loss of 0.55 LogMAR units for those with GLD >1000µm (P=0.02). Visual outcomes were not associated with gender or refractive error. CONCLUSION: Good visual outcome in myopic CNV is associated with younger age, smaller lesion size and earlier initiation of treatment. These factors are relevant for ophthalmologists considering treatment options for myopic CNV.