Simon Sheung Man Fung

Repeatability and Reproducibility of Choroidal Vessel Layer Measurements in Diabetic Retinopathy Using Enhanced Depth Optical Coherence Tomography

PURPOSE To describe novel segmentation protocols for choroidal layers, Sattlers medium and Hallers large vessel layers, using enhanced depth imaging optical coherence tomography (EDI-OCT), and to examine the repeatability and reproducibility of these measurements in eyes with diabetic retinopathy. METHODS Fifty-one patients with Type 2 diabetes mellitus were imaged using custom EDI scanning protocols. Detailed segmentation was performed to quantify the retina, choroid, Hallers large, and Sattlers medium vessel layers in the total macular circle (TMC) and foveal central subfield (FCS). The coefficient of repeatability (CR) and intraclass correlation coefficient (ICC) were used as a measure of repeatability and relative reliability within graders. Reproducibility or interobserver variability was assessed using Bland-Altman plots and 95% limits of agreement (LoA). RESULTS Intragrader CR of the retina, choroid, Sattlers, and Hallers layers for thickness measurements were 19.2, 26.9, 35.2, and 29.2 μm, respectively. Intergrader 95% LoA were 27.9, 41.5, 38.6, 31.1 μm (thickness), respectively. Choroidal sublayer measurements showed good intraobserver reliability (ICC 0.78-0.98). Interobserver variability for retinal and choroidal measurements was not significantly different (P > 0.45). Measurements from the TMC showed slightly better repeatability and agreement compared with the FCS alone. Mean intergrader differences were reduced after training, and were most apparent in choroidal sublayers. CONCLUSIONS The choroidal vascular sublayers can be quantified with good reliability, repeatability, and reproducibility. Accurate quantitative assessment of these sublayers may provide new insights into the role of the choroid in visual loss in patients with diabetic retinopathy, and prove useful for future clinical trials.

Are practical recommendations practiced? A national multi-centre cross-sectional study on frequency of visual field testing in glaucoma

Aim To estimate current clinical practice for frequency of visual field (VF) monitoring in glaucoma in England. Methods A cross-sectional review of all patients with chronic open angle glaucoma (COAG) attending specialist glaucoma clinics at six hospitals in England was performed. The number of VF tests undertaken prior to the study date and during the first 2 years since diagnosis were recorded and compared with European Glaucoma Society (EGS) guidelines for newly-diagnosed patients. Clinician-requested monitoring intervals were compared with intervals from the National Institute of Clinical Excellence (NICE) guidelines, and the relationships with disease severity, intraocular pressure (IOP) and glaucoma progression status were reviewed. Results One-hundred and four patients with COAG were included. 73 patients had at least 2 years of follow-up. Median (IQR) total number of VF tests and in the first 2 years of diagnosis were 4 (2–7) and 2 (2–3), respectively. No patients met EGS guidelines, but 87% of patients had their monitoring intervals requested in accordance with NICE guidelines. These intervals were not related to disease severity or VF stability (Kruskal–Wallis test, p=0.25) but shortened significantly when IOP control was inadequate or when the overall clinical impression was disease progression (p<0.001). Conclusions Most newly-diagnosed COAG patients receive less than three VFs in the first 2 years following diagnosis and an average of 0.7 VF per year over the duration of follow-up.

Altered Patterns of Fungal Keratitis at a London Ophthalmic Referral Hospital: An Eight-Year Retrospective Observational Study.

Purpose In previous studies of fungal keratitis (FK) from temperate countries, yeasts were the predominant isolates, with ocular surface disease (OSD) being the leading risk factor. Since the 2005–2006 outbreak of contact lens (CL)-associated Fusarium keratitis, there may have been a rise in CL-associated filamentary FK in the United Kingdom. This retrospective case series investigated the patterns of FK from 2007 to 2014. We compared these to 1994–2006 data from the same hospital. Design Retrospective observational study. Methods All cases of FK presenting to Moorfields Eye Hospital between 2007 and 2014 were identified. The definition of FK was either a fungal organism isolated by culture or fungal structures identified by light microscopy (LM) of scrape material, histopathology, or in vivo corneal confocal microscopy (IVCM). Main outcome measure was cases of FK per year. Results A total of 112 patients had confirmed FK. Median age was 47.2 years. Between 2007 and 2014, there was an increase in annual numbers of FK (Poisson regression, P = .0001). FK was confirmed using various modalities: 79 (70.5%) by positive culture, 16 (14.3%) by LM, and 61 (54.5%) by IVCM. Seventy-eight patients (69.6%) were diagnosed with filamentary fungus alone, 28 (25%) with yeast alone, and 6 (5.4%) with mixed filamentary and yeast infections. This represents an increase in the proportion of filamentary fungal infections from the pre-2007 data. Filamentary fungal and yeast infections were associated with CL use and OSD, respectively. Conclusions The number of FK cases has increased. This increase is due to CL-associated filamentary FK. Clinicians should be aware of these changes, which warrant epidemiologic investigations to identify modifiable risk factors.

Femtosecond laser-assisted lock-and-key shaped penetrating keratoplasty

The advent of the femtosecond laser in ophthalmology allows precise and customised corneal graft configurations at the graft-host junction. Recent studies have yielded a variety of wound shapes, all of which increase the surface area at the graft-host junction, resulting in better wound approximation, faster healing and earlier suture removal with comparable or reduced astigmatism.1–5 Among them, the mushroom and top hat configurations have been shown to be mechanically more stable than the traditional penetrating keratoplasty (PK) and other wound shapes when sutures were applied.5 This enhanced stability was attributed to the peripheral flange that acts as a valve and prevents wound leakage. In this study, we developed a novel ‘lock-and-key’ configuration for PK …

Mobile femtosecond laser platform for pediatric cataract surgery

Purpose: To describe the use of a mobile femtosecond laser platform in assisting paediatric cataract surgery. Methods: A mobile femtosecond laser was brought into the operating room and calibrated on the day of the surgery. After general anesthesia is induced, the femtosecond laser was docked onto the eyes with a liquid-filled interface, without any perioperative adaptations or additional surgical procedures. An anterior capsulotomy was created with the femtosecond laser, followed by conventional cataract extraction and intraocular lens implantation. Results: Five eyes of 3 children with congenital cataracts were treated with this technique. Docking and capsulorhexis were successful in all cases. No perioperative or intraoperative complications were noted in any of the cases. At median follow-up of 15 months (range 6-18 months), all patients had improved best-corrected visual acuity. Conclusions: Using the mobile femtosecond laser platform, a perfectly sized anterior capsulotomy could be created with high precision and accuracy in paediatric cataract cases, while ensuring that perioperative care for the children undergoing the procedure was not compromised.

Ophthalmomyiasis interna masquerading as orbital cellulitis

Ophthalmomyiasis interna posterior is a rare condition caused by the invasion of the ocular posterior segment by the larval form of certain flies in the order Diptera. The main clinical features are reduced visual acuity, intense posterior uveitis, and neuroretinitis. Treatment of this condition is predominantly surgical, including argon laser photocoagulation for subretinal larva and pars plana vitrectomy for intravitreal infection. We report a case of ophthalmomyiasis interna posterior in a 12-year-old girl that masqueraded as orbital cellulitis and was successfully treated with Nd:YAG laser photodisruption.

Authors’ response to laboratory model of bursting pressures of femtosecond laser-assisted penetrating keratoplasty wounds using novel pattern designs

We read with interest the article ‘Laboratory model of bursting pressures of femtosecond laser-assisted penetrating keratoplasty wounds using novel pattern designs’ by Gilmer et al .1 We would like to congratulate their work in demonstrating the stability of different wound designs in femtosecond laser-assisted keratoplasties, particularly regarding their Bolt shape wound interface design. In addition, we would also like to bring their attention to …