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Supriya Dabir,1 Mohan Rajan,1 Liji Parasseril,1 Vaidehi Bhatt,2 Preetam Samant,3 CAB Webers,4 TTJM Berendschot4 1Department of Retina, Rajan Eye Care Pvt Ltd, Chennai, India; 2Rajiv Gandhi Medical College, Thane, India; 3Department of Retina, PD Hinduja Hospital and Medical Research Center, Mumbai, India; 4University Eye Clinic, Maastricht, the NetherlandsCorrespondence: Supriya DabirRajan Eye Care Hospital Pvt. Ltd, No. 5, Vidyodaya East 2nd Street, T. Nagar, Chennai, Tamil Nadu 600017, IndiaTel +919900974800Email supriad@gmail.comPurpose: Diabetic macular oedema (DME) is a vision-threatening complication of diabetic retinopathy. Spectral domain optical coherence tomography angiography (OCTA) is useful for assessing DME. We performed serial OCTA measurements before and after 3 monthly intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections to understand its relationship with best corrected visual acuity (BCVA), central macular thickness (CMT) and vascular indices.Methods: OCTA assessment consisting of 6 × 6 mm scans centred on fovea and en-face retinal angiograms were obtained. Scans were done at baseline and at 1 month following each of the 3 intravitreal injections of anti-VEGF (ranibizumab, Lucentis®).Results: Our prospective study included 24 eyes of 24 subjects, aged 63.0 ± 5.0 years. There was a mean gain of 0.07 LogMAR (3 letters) and reduction of CMT, vessel density (VD) and perfusion density (PD) by end of 3rd month. CMT was independently associated with improvement in BCVA. There were significant reductions in FAZ area, VD and PD over 3 months from baseline.Conclusion: At three months, intravitreal anti-VEGF therapy is associated with visual function recovery in DME, with reduction in CMT being the most reliable predictor of response. OCTA shows a reduction in VD and PD respectively suggestive of reduced macular perfusion in the short term. Simultaneous reduction in FAZ size can be due to reversal of manual displacement of the retinal capillaries resulting from resolution of intraretinal oedema.Keywords: diabetic macular oedema, superficial capillary plexus, vascular density, perfusion density, foveal avascular zone, optical coherence tomography angiography, macular ischemia

Ophthalmology is a technology-driven medical speciality with rapid advances in imaging science, both in hardware and software. This thesis aims to study the structure and function of the retina, the nerve layer of the eye. We discuss two modalities in this thesis, namely adaptive optics (AO) to study the neural network and optical coherence tomography angiography (OCTA) to analyse the blood vessels of the retina. These advances in retinal imaging have allowed for better understanding of the eye in health and disease and may be a surrogate marker for systemic health.

Purpose To compare the characteristics of eyes that had manual vs. automated segmentation of choroidal neovascular membrane (CNVM) using optical coherence tomography angiography (OCTA). Methods All patients with CNVM underwent OCTA using the Zeiss Angioplex Cirrus 5000. Slabs of the avascular outer retina, outer retina to choriocapillaris (ORCC) region and choriocapillaris were generated. Manual segmentation was done when there were significant segmentation artifacts. Presence of activity of CNVM was adjudged by the presence of subretinal fluid (SRF) on structural OCT and was compared to activity detected on en face OCTA slabs based on well-defined criteria. Results Eighty-one eyes of 81 patients were recruited of which manual segmentation was required in 46 (57%). Eyes with automated segmentation had significantly more CNVM in the ORCC (75%) whereas those with manual segmentation had deeper CNVM (sub-RPE = 22%, intra-PED = 22%) (p Conclusions Manual segmentation of OCTA is required in more than 50% eyes with CNVM and this progressively increases with increasing depth of CNVM location from the ORCC to below the RPE. There is moderate concordance between OCTA and structural OCT in determining CNVM activity.

To assess the safety and efficacy of a single session of subthreshold micropulse (SM) yellow laser (577 nm) in the treatment of chronic central serous chorioretinopathy (CSCR).This was a retrospective analysis of 15 eyes of 13 patients with CSCR of3 months duration who had been treated with SM yellow laser (577 nm). All patients had been treated using multiple spots of laser with a duty cycle of 10% over areas of focal and diffuse leak, as seen on fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA). Reduction in subretinal fluid height on spectral domain optical coherence tomography (SD-OCT) was used to measure the response to treatment.The mean follow-up was at 8 weeks (4-19 weeks). All eyes responded to treatment. The mean subretinal fluid height pre and post treatment was 232 and 49 μm, respectively, showing a 79% average reduction (P0.001) in fluid height. There was no evidence of retinal pigment epithelium or retinal damage on SD-OCT, FFA, or fundus autofluorescence. Median visual improvement was one line on Snellen's visual acuity chart (P=0.015). Microperimetry was performed in eight eyes of which six eyes (75%) showed an improvement in the threshold values post treatment.SM yellow laser is an effective treatment option for chronic CSCR.

Optical coherence tomography (OCT) has revolutionized imaging of ocular structures and various disease conditions. Though it has been used in the clinic for some decades, the OCT has only recently found its way into the operating theater. Early attempts at intraoperative OCT, hand-held and microscope mounted, have already improved our understanding of the surgical pathology and the role it might play in surgical decision-making. The microscope-integrated OCT now allows seamless, high-resolution, real-time imaging of surgical maneuvers from the incision to wound closure. Visualization of instruments and intraoperative tissue manipulation are possible with this in vivo modality and, therefore, help improve the outcome of surgery. In this article, we describe the advantages it offers during various vitreoretinal procedures.

Introduction: Diabetic macular edema (DME) is a vision-threatening complication of diabetic retinopathy. The current practice of management is a" trial and error "method of using intravitreal antivascular endothelial growth factor (VEGF)'' or steroids to treat the patient and watch the response. However, if the patient's genetic profile helps us choose appropriate medicine, it would help customize treatment option for each patient. This forms the basis of our study. Materials and Methods: A case-control, prospective, observational series, where DME patients were treated with bevacizumab and subclassified as treatment naive, treatment responders, and treatment nonresponders. Blood samples of 20 subjects were studied, with five patients in each of the groups (nondiabetic-group 1, treatment naive-group 2, treatment responder-group 3, and treatment nonresponder-group 4). Whole blood RNA extraction followed by labeling, amplification and hybridization was done, and microarray data analyzed. Genes were classified based on functional category and pathways. Results: The total number of genes upregulated among all three experimental groups was 5, whereas 105 genes were downregulated. There were no common genes upregulated between the responders and nonresponders. There was only one gene upregulated between the diabetic and diabetic responders posttreatment. There were 19 genes upregulated and 8 genes downregulated in the inflammatory pathway in group 2 versus group 1. There were no downregulated genes detected in vascular angiogenesis and transcription group. There were identical numbers of genes up-and downregulated in the inflammatory pathway. Seventeen genes were upreguated and 11 genes downregulated in receptor activity, which remained the predominant group in the group classification. Discussion: In summary, this study would provide an insight into the probable signaling mechanisms for disease pathogenesis as well as progression. This type of study eventually would aid in developing or improvising existing treatment modules with a rational approach towards personalized medicine, in future addressing the differential responses to treatment.

We report a 56-year-old male patient, complaining of metamorphopsia in his left eye nevertheless visual acuity, slit lamp, and fundus examinations were within normal limits. Microperimetry (MAIA, Centervue, Italy) revealed central field loss and spectral domain optical coherence tomography (Spectralis, Heidelberg, Germany) showed disrupted cone outer segment tip layer. The patient had a diagnosis of cutaneous melanoma in his foot for which an excision biopsy with lymph node dissection was performed 5 months earlier. Our clinical diagnosis was melanoma-associated retinopathy. Electrophysiology confirmed the diagnosis. Adaptive optics retinal imaging (Imagine eyes, Orsay) was performed to assess the cone mosaic integrity across the central retina. This is the first report on the investigation of autoimmune retinopathy using adaptive optics ophthalmoscopy. This case highlights the viability of innovative diagnostic modalities that aid early detection and subsequent management of vision threatening retinal.

Purpose: To evaluate visual outcome and factors affecting visual outcome in herpes zoster ophthalmicus (HZO). Methods: A prospective, longitudinal, observational study was undertaken in 64 consecutive patients with HZO presenting within 72 h of rash onset. Patients underwent detailed ophthalmological and dermatological examinations at presentation, with follow up at first, second and fourth weeks and third and sixth months. All patients received both systemic and topical acyclovir. The main outcome measure was best-corrected visual acuity at 6 months' follow up. Local and systemic factors were correlated with visual outcome using univariate and multivariate analyses. Results: Overall visual outcome was good, with 36/64 (56.3%) patients having a visual acuity of 6/6 or better. Mild visual loss occurred in 22/64 (34.3%), moderate loss in 3/64 (4.7%) and severe loss in 3/64 (4.7%); moderate to severe visual loss was due to severe uveitis (2), neurotrophic keratitis (1) and cataract (3). Increasing age (P = 0.04), positive Hutchinson sign (P = 0.001), absent corneal sensation (P = 0.01), corneal epithelial lesions (P = 0.03) and uveitis (P

Introduction Herpes zoster ophthalmicus (HZO) is characterized by a typical vesicular eruption affecting the distribution of the ophthalmic division of the trigeminal nerve which can be of varying severity. The correlation of eruption severity and ocular involvement and subsequent visual loss is still to be established. In this prospective longitudinal study we evaluated the correlation of eruption severity with ocular complications, visual outcome and postherpetic neuralgia. Methods Patients with HZO underwent detailed ophthalmological and dermatological examination at presentation and follow-up on 1st , 2nd and 4th week and 3rd and 6th month. Eruption severity was graded as mild, moderate and severe based on the number of vesicles. The correlation of eruption severity and distribution with ocular complications, visual outcome and postherpetic neuralgia was statistically evaluated. Results Severe eruption was seen in 14(28%), moderate eruption in 21(42%) and mild eruption in 15(30%). Severe eruption was significantly associated with increased incidence and severity of ocular involvement (p = 0.04 and p = 0.04 respectively), occurrence of uveitis (p = 0.004), reduced visual outcome (p = 0.002) and the occurrence of PHN (p = 0.05). Lacrimal nerve involvement was also associated with increased incidence (p = 0.03) and severity (p = 0.02) of ocular complications and visual loss (p = 0.01). Conclusion Increasing eruption severity is a good predictor of occurrence of ocular complications and subsequent visual loss in HZO. Presence of a severe eruption is an indication for early ophthalmic intervention. Nasociliary nerve and lacrimal nerve involvement are also good predictors of ocular complications.

We report the case of a 25-year-old male patient who presented with complaints of redness, photophobia, and decreased vision in the right eye of a week's duration. Slit-lamp biomicroscopic examination revealed a cream-colored, irregular elevated inferior iris mass, extending on to the anterior lens surface. Differential diagnoses of a fungal granuloma, a medulloepithelioma, and an amelanotic melanoma were considered. An excisional biopsy of the mass was performed through a superior clear corneal incision. Polymerase chain reaction analysis of the aqueous humor showed a positive pan fungal genome. Histopathology of the biopsied mass showed a giant cell granuloma with surrounding numerous branching, septate hyphae. Culture growth revealed Aspergillus fumigatus We report this case because of the rarity of Aspergillus iris granuloma as a primary presentation of endogenous Aspergillosis and review the relevant literature. Absence of a significant systemic history compounded the diagnostic dilemma in our patient. Definitive differentiation of this rare entity from a foreign body, amelanotic melanoma, and other inflammatory conditions such as sarcoidosis and tuberculosis, may be possible only on microbiological and histo-pathological evaluation.

To study whether there exists a relationship between retinal nerve fiber layer thickness and oxygen saturation and to identify whether perivascular thickness (pRNFL) or quadrant thickness (qRNFL) has a stronger correlation.Patients without any detectable ocular abnormality on complete ophthalmic evaluation underwent non-invasive photo-spectrometric retinal oximetry on the Oxymap T1 retinal oximeter (Oxymap hf, Reykjavik, Iceland) and spectral-domain optical coherence tomography to determine if the pRNFL (Spectralis, Heidelberg, Germany) and the qRNFL (RtVue, Optovue) correlated with the measured light intensities and the calculated retinal oxygen saturations.30 eyes of 30 patients (120 arterioles, 120 venules) were included in the study. The mean arteriolar saturations (%) were temporal: 84.5 (95% CI 82.7-86.3) and nasal: 93.5 (95% CI 91.0-95.8); venous saturations were temporal: 54.4 (95% CI 52.9-55.9) and nasal: 59.9 (95% CI 58.3-61.4). The mean pRNFL thickness (µm) around arterioles was temporal: 153.1 (95% CI 146-159) and nasal: 109.4 (95% CI 103-115); around venules it was temporal: 147.4 (95% CI 140-154) and nasal: 101.2 (95% CI 95-107). The oxygen saturations correlated significantly with pRNFL (arteriolar r = -0.514; p0.001 and venous r = -0.513; p0.001) but did not show a significant correlation with qRNFL values.This relationship between perivascular RNFL could be physiological or artifactual. If physiological, it would explain and form the basis of altered oxygen saturation in a multitude of diseases. If artifactual, it would necessitate the incorporation of a pRNFL correction. However, the results of this study enable us to expect increased saturation in areas of thinner RNFL or vice versa with the current methodology of retinal vessel oximetry as obtained by dual-wavelength photo-spectrometric fundus imaging.

Optical Coherence Tomography (OCT) is a noninvasive technique and depth-resolved imaging modality which is a prominent ophthalmic diagnostic tool. In this paper, an automated segmentation algorithm to detect few intra-retinal layers which are important for Edema detection present in Spectral Domain Optical Coherence Tomography (SDOCT) images is presented. An algorithm for accurate segmentation of intra-retinal layers for normal subjects and patients with edema is discussed. The layers segmented are Inner Limiting Layer (ILM) and Retinal Pigment Epithelium (RPE) layer. The thickness is measured and then based on the thickness the image is classified as edema or non-edema. The accuracy of the algorithm is found to be more than that of the standard edge based segmentation techniques which are more prone to detection of false and disjoint edges. The graph based segmentation is solely based on pixel intensity variation and distance between neighbour pixels. Using the weighing scheme and shortest path search, it eases the task by identifying the neighbourhood pixel having same or similar intensity value and connects it by the path having the least weight. This segmentation method is less prone to noise and the preprocessing step can be considered as optional.

Objective To study the oxygen saturation profile in normal Asian Indian eyes. Design A cross sectional prospective study. Subjects Ninety eight consecutive patients presenting to our hospital with best corrected distance visual acuity (BCVA) of 20/20 and a normal ophthalmic examination were included in the study. Patients having any ocular or systemic disease were excluded from the study. Materials and Methods Oximetry was performed on all subjects with the Oxymap T1 retinal oximeter (Oxymap hf, Reykjavik, Iceland). Main Outcome Measures The images were analysed for oxygen saturation and diameter. Results The mean age was 33 years (Range: 18-63; SD: 12.4). The average arteriolar saturation was 90.3 ± 6.6% and the venous saturation was 56.9% ± 6.3. The average A-V (arterio-venous) difference was 33.2% ± 5.2. There was an increase in arteriolar (R2 = 0.264; p=0.001) and venous saturation (R2 = 0.151; p=0.001) with age. There was no significant change in the arterio-venous saturation difference (AVSD). The inferotemporal quadrant had the lowest saturations. Age correlated positively with ocular perfusion pressure (OPP)(R2 = 0.07; p=0.007). OPP correlated positively with global arteriolar saturation (R2=0.057, p=0.018). Conclusion This study provides the normative database for an Indian population and is comparable to previous studies. Age, vessel diameter and OPP were the significant factors that influenced the saturation. Arteriolar and venous saturations increased with age while the AVSD did not change significantly.

To describe the parafoveal cone arrangement in emmetropic subjects and its variations with eccentricity, meridians and change in axial length in Indian eyes.We imaged 25 subjects using compact adaptive optics (AO) retinal camera prototype, the rtx1. Imaging was done at 1, 2, and 3° eccentricity from the fovea in four meridians: nasal, temporal, superior, and inferior.A statistically significant drop in the cone packing density was observed from 2 to 3° (2° eccentricity=25 350/mm(2) (5300/mm(2), 8400-34 800/mm(2)) 3° eccentricity=20 750/mm(2) (6000 mm(2), 9000-33 670/mm(2))) P0.05. The spacing correspondingly increased with increase in distance from the fovea (2° eccentricity=6.9 μm (0.70 μm, 5.95-11.6 μm)) and 3°eccentricity=7.80 μm (1.00 μm, 6.5-13.5 μm) P0.05. As the axial length increases, the cone density significantly decreases. Interocular variations were noted.With the advent of AO, visualization at the cellular level is now possible. Understanding the photoreceptor mosaic in the parafoveal space in terms of its density, spacing, and arrangement is crucial so as to detect early pathology and intervene appropriately. Newer therapeutic modalitites that are targeted at the cellular level like yellow micropulse laser, stem cells, gene therapy and so on may be better monitored in terms of safety and efficacy.

To evaluate visual outcome and factors affecting visual outcome in herpes zoster ophthalmicus (HZO).A prospective, longitudinal, observational study was undertaken in 64 consecutive patients with HZO presenting within 72 h of rash onset. Patients underwent detailed ophthalmological and dermatological examinations at presentation, with follow up at first, second and fourth weeks and third and sixth months. All patients received both systemic and topical acyclovir. The main outcome measure was best-corrected visual acuity at 6 months' follow up. Local and systemic factors were correlated with visual outcome using univariate and multivariate analyses.Overall visual outcome was good, with 36/64 (56.3%) patients having a visual acuity of 6/6 or better. Mild visual loss occurred in 22/64 (34.3%), moderate loss in 3/64 (4.7%) and severe loss in 3/64 (4.7%); moderate to severe visual loss was due to severe uveitis (2), neurotrophic keratitis (1) and cataract (3). Increasing age (P = 0.04), positive Hutchinson sign (P = 0.001), absent corneal sensation (P = 0.01), corneal epithelial lesions (P = 0.03) and uveitis (P0.001) were significantly associated with visual loss. Uveitis was found to be the best predictor of visual loss in HZO on multivariate analysis.The overall visual outcome is good in HZO patients receiving antiviral therapy. Hutchinson's sign and anterior uveitis were found to be strong predictors of visual loss in HZO. Presence of these predictors calls for close monitoring.

The purpose was to study the disruption of the inner segment (IS) and outer segment (OS) junction associated with suboptimal visual outcome after successful retinal detachment surgery with an otherwise normal foveal contour and thickness.A comparative study of 2 groups, i.e., group I-suboptimal visual outcome (visual acuity20/40) and group II-optimal visual outcome (visual acuityor =20/40), with 7 eyes of 7 patients in each group rhegmatogenous retinal detachment surgery with an otherwise normal foveal contour and thickness on spectral domain-optical coherence tomography was evaluated for disruption of the IS and OS junction at 6 weeks using the crosshair protocol through the fovea. A 5 x 5-mm grid raster protocol (E MM5)imaged 256 squares of retina and the number of squares with IS and OS junction disruption was correlated with best-corrected visual acuity.Disruption of the IS and OS junction was seen in all 7 eyes of group I (100%)compared with 2 eyes in group II (28%), which was an obvious statistical difference (P =0.021). Also, a statistically significant correlation existed (r = 0.84, P0.05) when best-corrected visual acuity was plotted against the number of squares with IS and OS disruption. There was a statistically insignificant (P = 0.09) trend noted toward greater IS and OS junction disruption in eyes with prior macula off rhegmatogenous retinal detachments on univariate analysis.Disruption of the IS and OS junction could be a surrogate measure of the structural and functional health of the photoreceptors and can explain poor visual outcome in postsuccessful retinal detachment surgery with an otherwise normal foveal contour and thickness.

Correction to: Eye (2014) 28, 1488–1493; doi:10.1038/eye.2014.229; published online 3 October 2014 Since the online publication of the above article, it has been noted that the name of the fifth author was published incorrectly. The correct name is given above. This error has now been rectified, andthe corrected article appears in this issue.