SD OCT Research Articles

A study on correlation between automatedperimetry and optical coherence tomography findings in glaucoma suspects

To evaluate the correlation between optic disc and retinal nerve fiber layer (RNFL) parameters of SD OCT scan of optic disc, and, visual field indices of Humphrey visual field analyzer. This is a prospective, cross-sectional study of 47 patients who are glaucoma suspects. They have been screened for glaucoma by comprehensive ophthalmic examination including visual field testing by automated perimetry and optic nerve head and retinal nerve fiber layer thickness changes assessment by optical coherence tomography. Mean age of the glaucoma suspects was 54.35 ± 10.6 years. Women were having higher (58.7%) mean age as compared to men (41.3%). Mean IOP in glaucoma suspects was 17.97 mmHg. The mean CD ratio was measured as 0.66 ± 0.11 and with significant negative correlation between the mean MD and CD ratio values (p<0.05) and similarly between MD and Vertical CDR. PSD showed significant positive correlation with CDR and also with Vertical CDR. Correlation is noted between MD and average RNFL, with significant positive correlation between MD and superior RNFL. Spectral domain OCT, when used in combination with automated perimetry helps in early diagnosis of glaucoma.SD OCT of Optic disc alone can detect changes of RNFL in patients with normal discs and visual fields. Optic Disc OCT plays a vital role in diagnosing preperimetric glaucoma patients.

Optic nerve head and retinal nerve fiber layer changes by spectral domain optical coherence tomography in glaucoma suspects at tertiary care hospital

Introduction: Glaucoma is a progressive optic neuropathy characterized by functional loss or optic nerve dysfunction which is one of the leading causes of irreversible but preventable blindness. The aim of the study was to determine which of the retinal nerve fiber layer and optic nerve head parameters are reliable markers of optic nerve damage in glaucoma suspects. Methods: Observational cross-sectional study of 250 patient’s including147 glaucoma suspect eyes, 103 normal eyes. All subjects underwent complete eye examination and imaging with the spectral domain optical coherence tomography (SD-OCT) cirrus-TM OCT (Carl Zeiss Meditec, Dublin, CA). Retinal nerve fiber layer (RNFL) and optic nerve head (ONH) OCT protocols were used to evaluate all study participants. The main outcome measures were the difference in OCT parameters among groups. Results: Study shows statistically significant difference in the average RNFL thickness, superior, nasal, inferior, temporal quadrants, rim area, cup volume, average cup to disc ratio (CDR), vertical CDR with P value <0.001 between the two groups. Average CDR, vertical CDR and cup volume had significantly greater AROC values (ROC: 0.99, 0.98, 0.95) than RNFL parameters for discriminating glaucoma suspects from normal eyes. Conclusion: Assessment of RNFL, macular and ONH damage with SD-OCT has been proven useful for diagnosing the disease at different levels of severity, as well as for quantifying risk in glaucoma suspects. In our study ONH measurements, as provided by the SD OCT, have more diagnostic value than RNFL parameters in the diagnosis of glaucoma suspects from normal. Keywords: glaucoma suspects; optic nerve head; retinal nerve fiber layer; optical coherence tomography

Visual Outcomes in Malignant Hypertensive Retinopathy Cases: A Clinical and Spectral Domain Optical Coherence Tomography Study.

Objective The objective is to correlate visual outcomes in malignant hypertensive retinopathy with changes in systemic causative factors and spectral domain optical coherence tomography (SD OCT) morphologic parameters. Materials and methods This is a prospective observational study including patients presenting within two weeks of acute rise of systolic blood pressure (SBP) ≥ 180 mm Hg or diastolic blood pressure (DBP) ≥ 120 mm Hg and with posterior segment involvement in both eyes. Baseline SBP, DBP, mean arterial pressure (MAP), best corrected visual acuity (BCVA), and SD OCT parameters such as central macular thickness (CMT), subfoveal choroidal thickness (SCT), and sub-retinal fluid (SRF) height were measured at presentation and followed monthly up to three months. These variables at baseline and three months were compared and correlated. Results Thirty-three patients (66 eyes) having malignant hypertension were included in the study. Diverse clinical presentations noted among patients were optic disc edema, hard exudates in the macula, peripapillary splinter hemorrhage, cotton wool spots, Elschnig spots, exudative retinal detachment, optic neuropathy, and severe exudative retinopathy. SD OCTshows hyperreflective dots and intraretinal fluid with or without SRF.At three months, the mean SBP, DBP, MAP, CMT, SRF, and SCT all decreased significantly from baseline (p<0.001). Changes in SBP, DBP, MAP, and SCT correlated significantly with changes in BCVA (p<0.001). Conclusion In malignant hypertensive retinopathy, macular edema with SRF is the major cause of mild-to-moderate decrease BCVA at presentation, but macular ischemia, exudative RD, and optic neuropathy can cause a significant decrease in vision. A decrease in SBP, DBP, MAP, and SCT correlatesignificantly with visual outcomes.

Improved accuracy of spectral-domain optical coherence tomography and optical coherence tomography angiography for monitoring myopic macular neovascularisation activity

Background/aimsTo evaluate the diagnostic accuracy of spectral-domain optical coherence tomography (SD OCT) combined with OCT angiography (OCTA) for myopic myopic macular neovascularisation (MNV) activity.MethodsBoth eyes of patients with myopic MNV...

Comparison of focal loss volume, global loss volume, retinal nerve fiber layer thickness, and corneal epithelial thickness in eyes with glaucoma and suspicious optic discs

Abstract: PURPOSE: The purpose of this study was to study the role of the focal loss volume (FLV), global loss volume (GLV), and other spectral-domain optical coherence tomography (SD-OCT) parameters in early diagnosis of glaucomatous damage. METHODS: A retrospective study included records of 34 eyes with early glaucoma (Group A) and 17 eyes with suspicious optic discs (Group B). Retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), and corneal thickness parameters were assessed by the SD OCT (RTVue SD-OCT). These included the FLV, GLV, in addition to RNFL thickness, cup/disc ratio, GCC thickness, and anterior segment OCT for assessment of central corneal thickness and central corneal epithelial thickness. Data from both groups were subjected to statistical analysis. RESULTS: The FLV and GLV had the highest areas under the receiver operating characteristic curve in Group A eyes. FLV had higher (97.2%) specificity and was the earliest parameter to be affected by glaucomatous damage, followed by GLV. Moreover, Group A eyes had significant thinning of the RNFL (91.59 μm) compared to Group B (118.18 μm), and GCC thickness was also significantly thinner in Group A (92.07 μm) than in Group B (110.54 μm). Interestingly, Group A eyes had thinner corneal epithelium (nonsignificant) than Group B. CONCLUSION: FLV and GLV were of the greatest value in the assessment of early glaucomatous GCC degeneration.

Remodelling of the lamina cribrosa thickness in proliferative diabetic retinopathy as a pathogenetic factor of retrolaminar migration of silicone oil after vitrectomy

Aims/Purpose: to analyse the relationship of lamina cribrosa (LC) thickness in patients with proliferative diabetic retinopathy (PDR) after vitrectomy with SiO tamponade with retrolaminar migration of intraocular silicone oil (SiO).Methods: This retrospective study included 35 patients with PDR after vitrectomy with SiO tamponade who underwent unenhanced head computed tomography for various clinical indications. All images were visually evaluated for subretinal and retrolaminar migration of SiO involving the anterior visual pathway (optic nerve, optic chiasm, and optic tract) and the ventricular system. LC thickness was measured with spectral domain optical coherent tomography (SD OCT) using LC_Thickness_programm.m and main_low_noise_filters_programm.m, based on the adaptive compensation algorithm for eliminating a high‐level noise in the deep layers of optic nerve and improving the visualization of the LC posterior border, as well as for processing B‐scan with a set of 3 digital filters: Butterworth Low‐pass Filter inverion image, Wavelet Low‐pass Filter Analysis Daubechies original and inversion image.Results: In our patients with PDR the average LC thickness was 697 ± 35 μm (589 to 768 μm), that was 1.9 times higher than in healthy people (p &lt; 0.001). We detected subretinal and retrolaminar silicone oil migration in 10 of the 35 patients (28.57%), noting silicone oil at the optic nerve head (n = 2), retrolaminar optic nerve (n = 4), optic chiasm (n = 2), optic tract (n = 1) and in the lateral ventricles (n = 3). 3 patients had migration to 2 locations each (1 – in retrolaminar optic nerve and optic chiasm, 2 – in retrolaminar optic nerve and lateral ventricle). We compared the LC thickness of patients without and with subretinal and retrolaminar SiO migration. It was established that LC thickness of patients with subretinal and retrolaminar SiO migration was significantly less (589 to 658 μm) than in patients without SiO migration (673 to 768 μm). It should be noted that the number of cases positive for migration was small, limiting the statistical power and accuracy of the prevalence.Conclusions: A direct correlation between scleral LC thickness and retrolaminar migration of SiO in patients with PDR after vitrectomy with SiO tamponade was revealed.

Short-term Detection of Fast Progressors in Glaucoma: The Fast Progression Assessment through Clustered Evaluation (Fast-PACE) Study

To evaluate the performance of an intensive, clustered testing approach in identifying eyes with rapid glaucoma progression over 6 months in the Fast-PACE (Progression Assessment through Clustered Evaluation) study. Prospective cohort study. 125 eyes from 65 primary open-angle glaucoma (POAG) subjects. Subjects underwent two sets of 5 weekly visits (clusters) separated by an average of 6 months, then were followed with single visits every 6 months for an overall mean follow-up of 25 months (mean of 17 tests). Each visit consisted of testing with standard automated perimetry (SAP) 24-2 and 10-2, and spectral-domain optical coherence tomography (SD OCT). Progression was assessed using trend analyses of SAP mean deviation (MD) and retinal nerve fiber layer (RNFL) thickness. Generalized estimating equations were applied to adjust for correlations between eyes for confidence interval (CI) estimation and hypothesis testing. Diagnostic accuracy of the 6-month clustering period to identify progression detected during the overall follow-up. 19 of 125 eyes (15%, CI: 9%-24%) progressed based on SAP 24-2 MD over the 6-month clustering period. 14 eyes (11%, CI: 6%-20%) progressed on SAP 10-2 MD, and 16 (13%, CI:8%-21%) by RNFL thickness, with 30 of 125 eyes (24%, CI:16%-34%) progressing by function, structure, or both. Of the 35 eyes progressing during the overall follow-up, 25 had progressed during the 6-month clustering period, for a sensitivity of 71% (CI: 53%-85%). Of the 90 eyes that did not progress during the overall follow-up, 85 also did not progress during the 6-month period, for a specificity of 94% (CI: 88% - 98%). Of the 14 eyes considered fast progressors by SAP 24-2, 10-2 or SD OCT during the overall follow-up, 13 were identified as progressing during the 6-month cluster period, for a sensitivity of 93% (CI: 66% - 100%) for identifying fast progression with a specificity of 85% (CI: 77% - 90%). Clustered testing in the Fast-PACE study detected fast-progressing glaucoma eyes over six months. The methodology could be applied in clinical trials investigating interventions to slow glaucoma progression and may also be of value for short-term assessment of high-risk subjects.

Effect of pan retinal photocoagulation on macular ganglion cell - inner plexiform layer and peripapillary retinal nerve fibre layer thickness

: To determine the effect of pan retinal photocoagulation (PRP) on spectral domain optical coherence tomography (SD OCT) morphologic parameters like macular ganglion cell-inner plexiform layer (GCIPL), peripapillary retinal nerve fibre layer (RNFL) thickness and central macular thickness (CMT) in diabetic retinopathy cases. This is a retrospective study including 52 eyes with severe non-proliferative to proliferative diabetic retinopathy without macular oedema who required PRP. Macular GCIPL, CMT and peripapillary RNFL thickness measured at baseline and at 1-, 6-, 12- and 18-months post PRP with SD OCT. CMT, Macular GCIPL and peripapillary RNFL thickness increased significantly at 1 month (p&amp;#60;0.05), thereafter a decreasing trend noted at 6, 12 and 18 months. At 18 month CMT, GCIPL and RNFL thickness are higher than baseline but not statistically significant except temporal RNFL and Average GCIPL (p&amp;#60;0.05). A significant correlation found between changes in temporal RNFL and average GCIPL thickness (Pearson Correlation coefficient r= 0.652, 0.557, 0.782, 0.624 at 1, 6, 12 and 18 months respectively. P&amp;#60;0.05 for all values) CMT, macular GCIPL and peripapillary RNFL thickness increase following PRP; peaking at month 1 and stabilizing through next 18 months. Macular GCIPL thickness could be a reproducible indicator of temporal RNFL.

Comparison of the Short-Term Effect of Coffee, Energy Drink, and Water on the Eyes in Young Healthy Subjects.

We aim to compare the short-term effects of energy drink (ED), coffee, and water on the eyes of young healthy male subjects. The right eyes of 30 healthy male subjects were included in this study. We measured the intraocular pressure (IOP), mean arterial pressure (MAP), retinal thickness (RT), choroidal thickness (CT), and retinal nerve fiber layer (RNFL) thickness using spectral domain optical coherence tomography (SD OCT). The measurements for RT and CT were taken at the fovea as well as 1,500 µm nasal and temporal to the fovea.The measurements of the subjects were performed on the first day before water consumption and at 30 minutes and 60 minutes following intake of 250 mL of water. Measurements were repeated at the same regime on the second day after drinking 250 mL of coffee containing an equal concentration of caffeine in ED (37.5 mg) and on the third day after drinking 250 mL of ED. Repeated measures one-way analysis of variance test was used for statistical analysis. No significant difference was found for ocular perfusion pressure (OPP), MAP, RT, and IOP between the measurements taken on three consecutive days (p>0.05 for all). The CT values for the central, nasal, and temporal segments were significantly reduced in 0-30 and 0-60 minutes following coffee and ED intake (the range of p-value was <0.001-0.027). Both coffee and ED intake caused acute and significant decreases in CT that persisted for one hour in young healthy male subjects. The impactof ED intake on CT was attributed mainly to its caffeine content.

Angular Sign of Henle Fiber Layer Hyperreflectivity in Purtscher and Purtscher like Retinopathy.

Angular Sign of Henle Fiber Layer Hyperreflectivity (ASHH) is a marker of Henle Fibre layer ischemia. Our aim is to describe ASHH as a novel OCT sign in Purtscher and Purtscher like retinopathy. Here we present 3 Cases, one classical Purtscher Retinopathy and 2 Purtscher like Retinopathy who had ASHH on SD OCT imaging. Modalities like Colour fundus photography, cross-sectional OCT, OCT angiography (OCTA) and fluorescein angiography were used. Presence ASHH in Purtscher Retinopathy and Purtscher like retinopathy points towards a deep capillary plexus insult and has prognostic implications.

Understanding pseudopapilledema on spectral domain optical coherence tomography.

Optic nerve head drusen (ONHD), peripapillary hyperreflective ovoid mass-like structures (PHOMS), and horizontal hyperreflective lines (HHL) are commonly seen in eyes with pseudopapilledema on enhanced depth imaging (EDI) spectral domain optical coherence tomography (SDOCT). The objective of this study is to assess the frequency of ONHD, PHOMS, and HHL on spectral domain OCT in the eyes diagnosed to have pseudopapilledema. A retrospective case-control study included patients diagnosed as pseudopapilledema and had EDI SD OCT imaging of the optic nerve head (n = 48 eyes) and controls (n = 20 eyes). OCT scans through the optic nerve head were studied to diagnose ONHD, HHL, and PHOMS. One proportion z test was used to find the difference in proportions. Forty eight eyes of 27 subjects were studied. ONHD as described by the optic disc drusen Studies consortium was noted in 19 eyes (39.48%), P value-0.032, PHOMS in 31 eyes (64.6%), P value 0.043, HL in 19 eyes (39.48%), P value 0.032, and none of the normals had ONHD, PHOMS, and HHL. PHOMS are more frequently seen than ONHD and HHL in eyes with pseudopapilledema.

Novel surgical technique for macular holes with basal diameter &gt;1000 μ

Abstract: Closure rate of full-thickness macular holes (FTMHs) with basal diameter &gt;1000 μ is known to be poor. Patients presenting with FTMH having a minimum basal diameter of &gt;1000 μ without any coexistent retinal morbidity were offered vitrectomy, internal limiting membrane peeling, retinal massage, and aspiration of subretinal fluid from the MH. Visual acuity (VA) and spectral-domain optical coherence tomography (SD OCT) assessments were performed at baseline, week 1 after surgery and at postoperative months 1, 3, 6, and 12. VA, type of hole closure, presence of ellipsoid zone, and external limiting membrane defect were monitored. The primary endpoint was type 1 anatomical hole closure. Secondary outcome measure was a change in VA from baseline to 6-month follow-up and persistent hole closure at the final follow-up of 12 months. The mean age was 67.1 ± 9.1 years. Seven eyes were pseudophakic, and two underwent combined phacoemulsification with MH surgery. The mean minimum basal diameter of FTMH was 1162.4 ± 161 μ. The mean duration of visual loss was 11.3 ± 1.93 months. Type 1 closure of FTMH was seen in all patients on SD OCT, on the 7th postoperative day. The mean presenting VA was 1.06 ± 0.1 Logarithm of the minimum angle of resolution (logMAR). Best-corrected visual acuity improved to 0.91 ± 0.09 logMAR at 1-month follow-up (P = 0.005) (95% confidence interval [CI]: 0.061–0.251), 0.63 ± 0.1 logMAR (P &lt; 0.001) (95% CI 0.339–0.527) at 3 months, and 0.55 ± 0.05 logMAR (P &lt; 0.001) (95% CI 0.414–0.609) at 6 months. All holes were found closed at the final follow-up of 12 months. This novel technique can help achieve better outcomes and raise the primary anatomical success rate of FTMH with basal diameter &gt;1000 μ.

Pseudo optic disc duplication in association with posterior staphyloma

We report a case of 67 years old female diagnosed with pseudo-duplication of the optic nerve in association with posterior staphyloma. Her best corrected visual acuity in the right eye was finger counting close to face and 6/9 in the left eye. The anterior segment findings were normal however in the left eye; a vertically oval and excavated lesion was present nasally, with vessels dipping in the excavation similar to the optic disc. SD OCT of the pseudo-disc in the left eye revealed an excavation corresponding to the pseudo-disc, whereas the right eye was normal. Orbit MRI did not reveal any true duplication of the optic nerve or associated pathology. The pseudo-optic disc does not require any treatment as it does not impair visual acuity and patients are usually asymptomatic.

A comparative study of macular thickness measurements using spectral domain-optical coherence tomography before and after cataract surgery in patients with diabetes mellitus and their age matched controls

Patients with diabetes mellitus who undergo cataract surgery can be prone for macular edema post-operatively.Aimof this study wasto compare macular thickness in diabetics and non-diabetics, pre and post cataract surgery using SD-OCT. A Cohort study of 50 diabetic and 50 non-diabetic cataract patients who presented to ophthalmology out patient department, aged 50–70 years underwent macular thickness assessment using SD–OCT pre and post cataract surgery.The macular thickness showed a steady increase with time in non-diabetics and diabetics seen at baseline, 1 week post operative and 6 weeks post op. But the mean difference in diabetics was higher with a statistical significance(p&amp;#60;0.05).OCT is a noninvasive investigation which can differentiate between diabetic macular edema and postoperative cystoid macular edema. Preoperative assessment of macular thickness will be useful in the management of macular edema in both conditions, thus improving visual prognosis post cataract surgery.

ROLE OF ANTERIOR SEGMENT SPECTRAL DOMAIN OCT VS GONIOSCOPY IN DETECTING PRIMARY ANGLE CLOSURE IN A TERTIARY CARE CENTER IN UPPER ASSAM.

Objective- To evaluate anterior chamber angle to detect primary angle closure using anterior segment SD OCT vs Gonioscopy in a Tertiary Care Centre in upper assam. 30 eyes of 20 patients were examined. All patients unde Materials and methods- rwent comprehensive ocular examination, which included best corrected visual acuity, slit lamp examination, dilated fundus examination, intraocular pressure (IOP) measurement by Goldmann applanation tonometer, and gonioscopy. Consecutive patients fullling the inclusion and exclusion criteria were selected . After this, AS SD OCT was performed. Results A total of 30 eyes of 20 patients were examined over a period of six months. The mean age was found to be 50.75 ± 12.05 years. Out of 120 quadrants examined, primary angle closure was found in 75 quadrants in the gonioscopy (PTM not visible) and in 85 quadrants in the anterior segment OCT (Iridotrabecular contact). Overall sensitivity was found to be 95%, and specicity was found to be 70%. The mean trabecular iris angle and angle opening distance at 500 μm were found to be 10 degrees and 185 μm respectively. Conclusion Anterior segment SD OCT is a very sensitive tool that can act as a good screening tool for detecting angle closure

Intraocular Pressure and Rates of Macular Thinning in Glaucoma

To evaluate the effect of intraocular pressure (IOP) on the rates of macular thickness (ganglion cell layer [GCL] and ganglion cell-inner plexiform layer [GCIPL]) change over time measured by spectral-domain (SD) OCT. Retrospective cohort study. Overall, 451 eyes of 256 patients with primary open-angle glaucoma. Data were extracted from the Duke Ophthalmic Registry, a database of electronic medical records of patients observed under routine clinical care at the Duke Eye Center, and satellite clinics. All records from patients with a minimum of 6 months of follow-up and at least 2 good-quality Spectralis SD-OCT macula scans were included. Linear mixed models were used to investigate the relationship between average IOP during follow-up and rates of GCL and GCIPL thickness change over time. The effect of IOP on the rates of GCL and GCIPL thickness loss measured by SD-OCT. Eyes had a mean follow-up of 1.8 ± 1.3 years, ranging from 0.5 to 10.2 years. The average rate of change for GCL thickness was-0.220 μm/year (95% confidence interval [CI],-0.268 to-0.172 μm/year) and for GCIPL thickness was-0.231 μm/year (95% CI,-0.302 to-0.160 μm/year). Each 1-mmHg higher mean IOP during follow-up was associated with an additional loss of-0.021 μm/year of GCL thickness (P= 0.001) and-0.032 μm/year of GCIPL thickness (P= 0.001) after adjusting for potentially confounding factors, such as baseline age, disease severity, sex, race, central corneal thickness, and follow-up time. Higher IOP was significantly associated with faster rates of GCL and GCIPL loss over time measured by SD-OCT, even during relatively short follow-up times. These findings support the use of SD-OCT GCL and GCIPL thickness measurements as structural biomarkers for the evaluation of the efficacy of IOP-lowering therapies in slowing down the progression of glaucoma. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Optical biopsy – Optical coherence tomography guided excision of ocular surface squamous neoplasia

: To report the role of optical biopsy where the preoperative spectral domain optical coherence tomography (SD OCT) features were used for surgical margin clearance in ocular surface squamous neoplasia (OSSN) excision.In this prospectiveinterventional studypatients with clinically diagnosed OSSNundergopreoperative SD OCT and mass was excised with 3mm clearance with respect to the extent on OCT. Corneal, conjunctival margins and lamellar sclera was evaluated histopathologically. Twelve eyes of 11 patients with mean age of 59.2 ± 12.2 were studied. Hyper reflective epithelium, increased thickness, abrupt transition of corneal epithelium and increase back shadow were the features of OSSN noted. The mean functional epithelial thickness and epithelial thickness were 137.5± 60.6µm and 58.5±10.8 µm respectively. The histopathology confirmed as squamous cell carcinoma (SCC) (n=4, 33.3%), carcinoma in situ (CIN) (n=8, 66.6%). In CIN 2 eyes were severe dysplasia and 6 were moderate dysplasia. Corneal clearance was noted as 100 %. Of 36 conjunctival margins, the positive margin noted in 6 eyes (50%). Nasal margin (n=3) and temporal (n=3) were the common margins. There was no difference in clearance between CIN (50%) or SCC (50%) on conjunctival side. Two eyes with recurrence required and revision excision subsequent topical chemotherapyOptical biopsy by SD OCT though is an effective method for OSSN removal. Corneal margins showed better margin clearance than conjunctival.

Structural changes in the retina after implantation of subretinal three-dimensional implants in mini pigs.

The retinal structural changes after subretinal implantation of three-dimensional (3D) microelectrodes were investigated in a mini pig. Three types of electrode were implanted into the subretinal spaces of nine mini pigs: 75-μm-high 3D electrodes on a 200-μm-thick right-angled polydimethylsiloxane (PDMS) substrate (group 1); a 140-μm-thick sloped PDMS substrate without electrodes (group 2); and a 140-μm-thick sloped PDMS substrate with 20-μm-high 3D electrodes (group 3). One mini pig was used as a control. Spectral domain–optical coherence tomography (SD–OCT) images were obtained at baseline and 2, 6, and 12 weeks post-surgery. Retinal specimens were immunostained using a tissue-clearing method 3 months post-implantation. The 75-μm-high 3D electrodes progressively penetrated the inner nuclear layer (INL) and touched the inner plexiform layer (IPL) 2 weeks post-surgery. At 6 weeks post-operatively, the electrodes were in contact with the nerve-fiber layer, accompanied by a severe fibrous reaction. In the other groups, the implants remained in place without subretinal migration. Immunostaining showed that retinal ganglion and bipolar cells were preserved without fibrosis over the retinal implants in groups 2 and 3 during the 12-week implantation period. In summary, SD–OCT and immunohistology results showed differences in the extent of reactions, such as fibrosis over the implants and penetration of the electrodes into the inner retinal layer depending on different types of electrodes. A sloped substrate performed better than a right-angled substrate in terms of retinal preservation over the implanted electrodes. The 20-μm-high electrodes showed better structural compatibility than the 75-μm-high 3D electrodes. There was no significant difference between the results of sloped implants without electrodes and 20-μm-high 3D electrodes, indicating that the latter had no adverse effects on retinal tissue.

Intravitreal Dexamethasone Implant (IDI) Alone and Combined with Navigated 577 nm Subthreshold Micropulse Laser (SML) for Diabetic Macular Oedema.

Background: The anatomical and functional changes after intravitreal dexamethasone implant (IDI) alone and combined with navigated subthreshold micropulse laser (NSML) in diabetic macular oedema (DMO) were compared. Methods: Patients with a clinically confirmed diagnosis of non-proliferative diabetic retinopathy (NPDR) and DMO were enrolled in this prospective study and were randomly assigned to two different treatment groups: thirty patients were treated with IDI (IDI group), and the other 30 patients received IDI combined with NSML treatment (combined IDI/NSML group). All patients during a 6-month follow-up underwent best corrected visual acuity (BCVA) evaluation and spectral domain optical coherence tomography (SD OCT). The main outcome measures were: BCVA, central macular thickness (CMT); (3) choroidal vascularity index (CVI), subfoveal choroidal thickness (SCHT); and time to retreatment between IDI at baseline and the second implant in both groups. Results: BCVA, CMT, and SCHT significantly decreased starting from the 1-month follow-up and CVI from 3 months in both groups. The between-group differences were significantly different from 1-month follow-up for BCVA, from 5-month follow-up for CMT and SCHT, and from 4-month follow-up for CVI. The Needed to Treat analysis indicated that six patients would have to be treated with SML after IDI in order for just one person to receive a benefit. Conclusions: the combined treatment showed good anatomical and functional outcomes for the treatment of DMO. In addition, IDI/SML seems to reduce injection frequency over time, improving patients’ quality of life and reducing the socio-economic burden.

A STUDY TO COMPARE THE RETINAL NERVE FIBER LAYER (RNFL) MEASUREMENTS USING THE TD OCT 'STRATUS' AND THE SD OCT 'RTVUE' IN HEALTHY PARTICIPANTS AND GLAUCOMA PATIENTS

Background: To compare the RNFL measurements using the conventional Time Domain Optical Coherence Tomography (TD-OCT) 'Stratus' and the Spectral Domain Optical Coherence Tomography (SD OCT) 'RTVue' in healthy participants and glaucoma patients. ThisMethods: prospective cross-sectional study included 50 eyes in each of the two study groups as, healthy eyes and eyes of established glaucoma patients. Peripapillary RNFL thickness was measured by both machines in random order by the same operator on the same day with pupils uniformly dilated to over 5.0 mm. Three separate fast RNFL Scans were acquired with Stratus OCT, from which the most reliable scan was chosen for comparison. For RTVue, “RNFL3.45” scan protocol was used, which consists of four sets of 1024 “A-scans” along a 3.45 mm-diameter circle centered on the optic disc. There was a signicant difference in RNFL measurements between the two methods ,which was maximum in the superiorResults: quadrant and minimum in the nasal quadrant in both the groups In both the groups, RTVue RNFL measurements are thicker as. Conclusion: compared to that of Stratus with maximum quadrant mean RNFL measurement in the inferior quadrant and minimum in the nasal quadrant. Maximum difference in RNFL measurement between the two machines was at superior quadrant in both the groups.