Raeba Mathew

Treatment of proliferative diabetic retinopathy with anti-VEGF agents.

Proliferative diabetic retinopathy (PDR) is the most common cause of severe visual loss in people with diabetes. Although panretinal photocoagulation (PRP) remains the gold standard of care to date, several combinations of new treatment modalities have emerged. These approaches can be used to increase the extent of treatment, expedite the effect of laser treatment and provide alternate measures when laser delivery is difficult or impossible, especially in patients with vitreous haemorrhage. Currently, most of the research in this field is focussed on inhibitors of vascular endothelial growth factor (VEGF), referred to herein as anti‐VEGF agents. Although limited by their short‐lived effects and a lack of established protocols, anti‐VEGF agents are widely available, especially for the treatment of aggressive PDR. This review analyses published studies using anti‐VEGF agents alone or as an adjunct to other therapies in the treatment of PDR.

Spectral domain optical coherence tomography in patients with sickle cell disease

Aim To evaluate spectral domain optical coherence tomography (SD-OCT) changes in central retina and choroid in patients with sickle cell disease (SCD). Methods Data on visual acuity, severity of sickle cell retinopathy, macular volume scans and choroidal thickness on SD-OCT were analysed from 208 eyes of 107 consecutive patients referred for screening for SCD. The retinal and choroidal thickness of eyes with SCD were also compared with age and ethnicity matched controls. Results 44% of the eyes of patients with SCD showed discrete areas of retinal thinning in the temporal macular area. Proliferative sickle cell retinopathy was more prevalent in these eyes compared with SCD eyes with normal macular morphology (67% vs 48%; p=0.0017). The temporal total and inner retinal thickness, macular volume and choroidal thickness were significantly lower in patients with SCD compared with age, gender and ethnicity matched controls. Macular splaying (widening of the macular contour) was noted in 30% of eyes in both groups. The choroidal and retinal thickness values showed good intergrader reliability using weighted κ statistics (0.550–0.9). Conclusions Quantitative and qualitative changes on SD-OCT are present in asymptomatic SCD eyes. Proliferative retinopathy is more prevalent in eyes with discrete areas of macular thinning.

Predictive Value of Spectral-Domain Optical Coherence Tomography Features in Assessment of Visual Prognosis in Eyes With Neovascular Age-Related Macular Degeneration Treated With Ranibizumab

PURPOSE To determine whether pretreatment (baseline) optical coherence tomography (OCT) features can be used as predictors of visual acuity outcome at 12 months in eyes with neovascular age-related macular degeneration treated with intravitreal ranibizumab and to assess whether baseline OCT features can predict a change in visual acuity from baseline to 12 months. DESIGN Retrospective, observational study. METHODS We retrospectively evaluated the serial cross-sectional images of the macula obtained using the Spectralis OCT (HRA+OCT; Heidelberg Engineering) in 100 eyes of 94 patients attending a single center and undergoing treatment with intravitreal ranibizumab for neovascular age-related macular degeneration. The baseline OCT characteristics and visual acuity were correlated to the final visual acuity (Early Treatment Diabetic Retinopathy Study letters) and change in visual acuity after 12 months of monitoring and treatment. Univariate and multivariate analyses were carried out to correlate these morphologic features with the final visual acuity and the change in visual acuity. RESULTS Intact ellipsoid zone (P = .0001) and external limiting membrane in the subfoveal area (P < .0001) at baseline were the only 2 independent good prognostic indicators of final visual acuity at 12 months. However, none of the morphologic features at baseline could predict the change in visual acuity by 12 months. CONCLUSIONS The results suggest that integrity of the outer retinal layers at baseline is crucial for determining final visual acuity at 12 months in eyes undergoing treatment with ranibizumab for neovascular age-related macular degeneration.

Autofluorescence and high-definition optical coherence tomography of retinal artery occlusions

Background The purpose of this study is to illustrate the fundus autofluorescence and high-definition optical coherence tomography (HD-OCT) features of acute and long-standing retinal artery occlusions. Design Retrospective case series. Participants Patients with acute and chronic retinal and cilioretinal artery occlusions are included in this series. Methods A detailed clinical examination, color fundus photographs, autofluorescence, and HD-OCT of the subjects were performed. Results HD-OCT demonstrates the localized and well-demarcated thickening of the inner retina in the acute phase of arterial occlusions that correlates with the areas of blocked autofluorescence caused by the cloudy swelling of the retina. The areas of blocked autofluorescence disappear with chronicity of the disease and this corresponds to the thinning of the inner retinal layers on HD-OCT. Conclusion Heidelberg OCT and autofluorescence are useful tools to assess retinal arterial occlusions especially in subjects with unexplained visual field loss.

Determinants of Fixation in Eyes With Neovascular Age-Related Macular Degeneration Treated With Intravitreal Ranibizumab

PURPOSE To correlate the anatomic features of the macula with functional parameters like location and stability of fixation in patients with neovascular age-related macular degeneration treated with intravitreal ranibizumab injections. DESIGN Retrospective analysis. METHODS The location and stability of fixation were determined in 41 eyes of 41 patients treated with ranibizumab for neovascular age-related macular degeneration for at least 12 months. All patients underwent 3 injections of ranibizumab 1 month apart and were retreated according to predefined criteria. The fixation parameters measured with microperimetry were correlated to visual acuity, qualitative measures on optical coherence tomography, and patterns of autofluorescence. RESULTS The location of fixation was predominantly central in 68.29%, poor central in 2.4%, and predominantly eccentric in 29.27%. The fixation was stable in 80.5%, relatively unstable in 7.3%, and unstable in 12.2%. The factors that determined central and stable location of fixation were better visual acuity (P = .004), absence of subretinal thickening (P = .003), intact subfoveal third hyperreflective band (P = .006), and intact external limiting membrane (P = .036). Autofluorescence pattern within the 4-degree circle of fovea did not correlate with fixation characteristics. However, complete absence of autofluorescence in this area was a poor prognostic indicator for central fixation. CONCLUSIONS Anatomic characteristics of the macula determine fixation patterns in patients with neovascular age-related macular degeneration treated with intravitreal ranibizumab injections. Further studies focused on eyes with complete absence of autofluorescence in the central 4-degree circle of fovea may help to define the disease characteristics in this group.

Correlation of Fundus Fluorescein Angiography and Spectral-Domain Optical Coherence Tomography in Identification of Membrane Subtypes in Neovascular Age-Related Macular Degeneration

Aims: To assess the sensitivity and specificity of spectral-domain optical coherence tomography (SDOCT) for the determination of choroidal neovascularization (CNV) subtypes in neovascular age-related macular degeneration (AMD) compared to fundus fluorescein angiography (FFA) and also the agreement between the two procedures. Design: This was a retrospective, observational study. Methods: We evaluated and compared the CNV subtypes on FFA and OCT in 100 eyes initiated on ranibizumab for neovascular AMD. Results: SDOCT showed high sensitivity (85.7-98.3%) and specificity (84.2-100%) compared to FFA in the diagnosis of the CNV subtype. The area under the receiver-operating characteristic curve ranged from 0.9 to 0.93 (p value <0.0001) for the different CNV subtypes. Weighted kappa statistics showed a near-perfect agreement of 0.85 between the procedures. Conclusion: SDOCT is a reliable tool for the diagnosis of CNV subtypes in neovascular AMD obviating the need for an invasive procedure such as FFA.

Agreement between Time-Domain and Spectral-Domain Optical Coherence Tomography in the Assessment of Macular Thickness in Patients with Idiopathic Macular Telangiectasia Type 2

Purpose: To estimate the conversion factors to transpose macular thickness measurements on time-domain (TD) to various spectral-domain (SD) optical coherence tomography (OCT) machines in patients with macular telangiectasia type 2a (MacTel). Procedures: Macular scans on TD- and SD-OCT were performed on patients at the same visit. The retinal thickness values in various ETDRS subfields and macular volume were compared between different OCT machines. Results: The macular thickness and volume were significantly greater (p < 0.0001, r = 0.678-0.822) on SD-OCT. The mean differences in macular thickness between TD Stratus and SD-OCT by Spectralis, Cirrus and Topcon were 62, 41 and 20 μm, respectively. The conversion factor of macular thickness from TD-OCT to Spectralis, Cirrus and Topcon were +65, +39 and +25 μm, respectively. Conclusion and Message: The estimates of conversion of macular thickness from TD- to SD-OCT using simple mean differences between machines and those by linear regression were similar suggesting that the former may be used for the longitudinal follow-up of MacTel patients.

Advances in the diagnosis of sickle cell retinopathy

ABSTRACT Introduction: Sickle cell disease (SCD) is an occlusive vascular disease that affects the vasculature of any part of the body including retina. Although the proliferative form of sickle cell retinopathy (SCR) may be more potentially damaging leading to visual impairment, non-proliferative forms too manifest changes in macula and peripheral retina. Advances in management of systemic complications of SCD have improved patient survival into adulthood with better quality of life leading to increased frequency of all ocular complications. Hence regular screening and early diagnosis of SCR is important to forestall visually significant complications of the same. Areas covered: This article gives a review of recent advances in structural and functional diagnostic imaging modalities such as spectral domain optical coherence tomography (OCT), wide-field retinal fundus photography/angiography, OCT angiography, microperimetry, electroretinography, and multimodal imaging in assessment of SCR. A literature search was conducted on PubMed on diagnostic modalities in SCR. Considering rarity of the condition, large population studies are not available therefore articles on small studies and case series are also included. Expert opinion: Multimodal imaging allows a comprehensive evaluation of the central and peripheral features of SCR. This helps in early diagnosis of complications and timely intervention for effective management.