Lawrence P. Iu

The inner segment/outer segment junction: what have we learnt so far?

Purpose of review The advancement of optical coherence tomography has improved the resolution of in-vivo images of the retina. This has led to a wealth of novel knowledge regarding the microstructures of the photoreceptor layer and its relationship with visual functions under different pathological diseases. Recent findings Identification of the hyperreflective lines in the photoreceptor layer has been made possible by spectral domain optical coherence tomography. The inner segment/outer segment junction, external limiting membrane, cone outer segment tips, and the retinal pigment epithelium were thought to be the origins of the four hyperreflective lines seen in the photoreceptor layer. Integrity of these lines has been linked with visual functions in various retinopathies, and has been suggested to carry prognostic implications. Recovery of initially interrupted lines has been documented following successful treatment. Summary Identification of these hyperreflective lines may have clinical implications as visual function was found to correlate closely with their integrity. Restoration of these lines may indicate treatment response and potential visual recovery.

Sequential therapy with ranibizumab and dexamethasone intravitreal implant is better than dexamethasone monotherapy for macular oedema due to retinal vein occlusion

Purpose To evaluate the efficacy and safety of sequential therapy with ranibizumab followed by dexamethasone intravitreal implant compared with dexamethasone monotherapy for macular oedema (MO) secondary to retinal vein occlusion (RVO). Methods In this retrospective interventional study, the medical records of subjects with MO due to RVO who received either ranibizumab followed by dexamethasone intravitreal implant (Group 1) or dexamethasone-implant monotherapy (Group 2) were included. Primary outcome was the proportion of subjects who exhibited best-corrected visual acuity (VA) gain and resolution of MO within 6 months. Results Thirty-three eyes were included (17 in Group 1, 16 in Group 2). More subjects in Group 1 exhibited a VA gain of at least 0.5 (LogMAR units hereafter) than Group 2 (29% vs 0%, p=0.044). The speed of VA gain was greater in Group 1 (1.4±0.8 months vs 2.7±1.4 months, p=0.020). MO was controlled in more subjects in Group 1 at all measured time intervals, and this difference was statistically significant at 3 months and 4 months. Subjects with branch RVO experienced VA gain more rapidly if they were from Group 1 (p=0.023). Conclusions Sequential therapy was found to be more effective than dexamethasone monotherapy in treating MO due to RVO.

En-face optical coherence tomography in the diagnosis and management of age-related macular degeneration and polypoidal choroidal vasculopathy

Optical coherence tomography (OCT) is a noninvasive imaging modality providing high-resolution images of the central retina that has completely transformed the field of ophthalmology. While traditional OCT has produced longitudinal cross-sectional images, advancements in data processing have led to the development of en-face OCT, which produces transverse images of retinal and choroidal layers at any specified depth. This offers additional benefit on top of longitudinal cross-sections because it provides an extensive overview of pathological structures in a single image. The aim of this review was to discuss the utility of en-face OCT in the diagnosis and management of age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV). En-face imaging of the inner segment/outer segment junction of retinal photoreceptors has been shown to be a useful indicator of visual acuity and a predictor of the extent of progression of geographic atrophy. En-face OCT has also enabled high-resolution analysis and quantification of pathological structures such as reticular pseudodrusen (RPD) and choroidal neovascularization, which have the potential to become useful markers for disease monitoring. En-face Doppler OCT enables subtle changes in the choroidal vasculature to be detected in eyes with RPD and AMD, which has significantly advanced our understanding of their pathogenesis. En-face Doppler OCT has also been shown to be useful for detecting the polypoid lesions and branching vascular networks diagnostic of PCV. It may therefore serve as a noninvasive alternative to fluorescein and indocyanine green angiography for the diagnosis of PCV and other forms of the exudative macular disease.

1-year results of combined half-dose photodynamic therapy and ranibizumab for polypoidal choroidal vasculopathy

BackgroundTo evaluate the efficacy and safety of half-dose photodynamic therapy (PDT combined with ranibizumab for polypoidal choroidal vasculopathy (PCV). PCV is commonly treated with a combination of anti-vascular endothelial growth factor and standard-dose photodynamic therapy (PDT). Choroidal ischemia and visual loss can be resulted from the standard-dose PDT. Half-dose PDT has proved to produce similar results and safety profile in treating central serous chorioretinopathy. Half-dose PDT may offer an alternative for PCV cases where the damage to choroidal vasculature maybe less. Here, we report the efficacy of treating PCV cases with combination of ranibizumab and half-dose PDT.MethodsIn this prospective, non-comparative, interventional case series, 19 treatment-naive eyes were treated with combined half-dose PDT and ranibizumab. All subjects were followed up for 12 months with measurement of best-corrected visual acuity (BCVA), central foveal thickness (CFT) by optical coherence tomography. Indocyanine green angiogram (ICG) was performed every 3-monthly, and subjects assessed in terms of polyp regression rates, changes in vision and central foveal thickness, need to repeat half-dose PDT. Subgroup analysis was performed based on ICG features.ResultsThe mean logMAR BCVA improved from 0.64 at baseline to 0.41 at 12 months. The mean CFT improved from 459.6mum at baseline to 384.2mum at 12 months. The difference between baseline BCVA and CFT and that at 12 months were statistically significant (both P = 0.03). Polyp regression rate after one half-dose PDT was 42.1 %. This was 61.5 % in the polyp-only group, while that in the branching-vascular-network (BVN) group was 0 % (P = <0.01).ConclusionHalf-dose PDT combined with intravitreal ranibizumab was able to induce high polyp regression rate in PCV cases that had one single polyp.

Screening for retinopathy of prematurity and treatment outcome in a tertiary hospital in Hong Kong.

INTRODUCTION Studies on the prevalence and severity of retinopathy of prematurity in the local population are scarce. This study aimed to evaluate the prevalence, screening, and treatment outcome of retinopathy of prematurity in a tertiary hospital in Hong Kong. METHODS This cross-sectional study with internal comparison was conducted at Queen Mary Hospital, Hong Kong. The study evaluated 89 premature infants who were born at the hospital and were screened for retinopathy of prematurity, in accordance with the 2008 British Guidelines, between January 2013 and December 2013. The prevalences of retinopathy of prematurity and severe retinopathy requiring treatment were studied. RESULTS The mean (± standard deviation) gestational age at birth was 30+2 weeks ± 16.5 days (range, 24+1 to 35+5 weeks). The mean birth weight was 1285 g ± 328 g (range, 580 g to 2030 g). A total of 15 (16.9%) infants developed retinopathy of prematurity and three (3.4%) required treatment. In a subgroup analysis of extremely-low-birth-weight infants of <1000 g, 70.6% developed retinopathy of prematurity and 17.6% required treatment. Multivariate logistic regression analysis suggested low birth weight and patent ductus arteriosus were significantly associated with development of retinopathy of prematurity (P<0.001 and P=0.035, respectively). Among the three infants who received treatment for severe retinopathy of prematurity, all regressed successfully after one laser treatment. CONCLUSIONS Retinopathy of prematurity is a significant problem among premature infants in Hong Kong, especially those with extremely low birth weight. Our screening service for retinopathy of prematurity was satisfactory and treatment results were good. Strict adherence to international screening guidelines and vigilance in infants at risk are key to successful management of retinopathy of prematurity.

Successful treatment of intraocular post-transplant lymphoproliferative disorder with intravenous rituximab.

We reported a rare case of intraocular post‐transplant lymphoproliferative disorder (PTLD) arising in a 3‐year‐old liver transplant recipient who had a prior history of systemic PTLD. The first PTLD entered remission after treatment with intravenous rituximab and withdrawal of immunosuppressants. One year after remission, she presented with granulomatous uveitis and iris nodules in the right eye. Iris biopsy confirmed recurrence of intraocular PTLD, which resolved completely after a second course of intravenous rituximab. Pediatr Blood Cancer 2015;62:169–172.

One-year Results Of Half- Versus Standard-dose Photodynamic Therapy Combined With Ranibizumab For Polypoidal Choroidal Vasculopathy

Purpose: To explore the efficacy of half-dose verteporfin photodynamic therapy (hd-PDT) and standard-dose photodynamic therapy (sd-PDT), when combined with ranibizumab in the treatment of polypoidal choroidal vasculopathy. Methods: Subjects were allocated to either the hd-PDT arm or the sd-PDT arm. All subjects received an injection of ranibizumab and PDT treatment (dosage according to allocation) at baseline. Subjects were followed up monthly for 12 months, and re-treatment were given at each visit if criteria were met. Results: There were 26 subjects in the hd-PDT arm and 32 in the sd-PDT arm. Overall mean age was 69.3 ± 9.4 years. Baseline demographics and ocular features did not differ significantly between the two arms. Improvement in vision and reduction in central retinal thickness were similar between the two arms. When presenting, visual acuity was better than 20/50 (logarithm of the minimum angle of resolution 0.4), or when there were three or less polyps angiogram, those treated with hd-PDT tended to perform better than those treated with sd-PDT. Conclusion: In general, hd-PDT was able to produce similar results as sd-PDT. Subgroup analysis revealed superior results with hd-PDT when baseline vision was 20/50 or better, or when there were three or less polyps on indocyanine green angiography.

Serial Spectral-Domain Optical Coherence Tomography Findings in Acute Retinal Pigment Epitheliitis and the Correlation to Visual Acuity

PURPOSE To evaluate the features of acute retinal pigment epitheliitis (ARPE) at onset and in the course of recovery by serial spectral-domain optical coherence tomography (SD OCT) and the correlation to visual acuity (VA). DESIGN Retrospective cohort study. PARTICIPANTS Consecutive patients with ARPE. METHODS A review of medical records was performed. MAIN OUTCOME MEASURES Integrity of SD OCT retinal bands at onset and in the course of disease, time required to achieve each retinal band restoration, corresponding VA change, and final VA. RESULTS Four patients were included. Initial SD OCT showed a dome-shaped hyper-reflective lesion at the photoreceptor outer segment layer disrupting the ellipsoid zone (EZ) and interdigitation zone (IZ) (100%). In the early phase, there was also upward displacement of the external limiting membrane (ELM) and mild transient thickening of the retinal pigment epithelium (RPE)/Bruchs complex (Bc). Acute retinal pigment epitheliitis resolved in a sequence of (1) a decrease in height of SD OCT hyper-reflective lesion and the upwardly displaced ELM returning to its normal position with irregularity; (2) complete disappearance of the hyper-reflective lesion; (3) restoration of ELM; (4) restoration of EZ; and (5) restoration of IZ. The average time to restore ELM, EZ, and IZ was 4.3±5.2, 7.3±7.2, and 12.5±12.4 weeks, respectively, and the corresponding logarithm of the minimum angles of resolution (logMAR) VAs were 0.24±0.23, 0.09±0.07, and 0.05±0.06, respectively. Visual acuity improved when IZ was restored. CONCLUSIONS Early SD OCT revealed an inflammatory lesion in the photoreceptor outer segment layer displacing ELM. The RPE was involved only mildly and transiently. Recovery occurred in a sequence of ELM, EZ, and IZ restoration, and VA improved when the IZ was restored. These features suggested that the IZ (i.e., the contact between photoreceptors and RPE) is the primary site of inflammation in ARPE.