Immediate response to intravitreal treatment for macular edema due to diabetes and retinal vein occlusion.

PURPOSE: To objectively assess the immediate response to intravitreal treatment for macular edema and compare it across different agents. METHODS: This retrospective, comparative study included patients with macular edema due to diabetic retinopathy (DME) or vein occlusion who were treated with intravitreal injections of either steroids (triamcinolone acetonide or dexamethasone sustained release implant) or anti-vascular endothelial growth factor antibodies (VEGF). The central retinal thickness (CRT) and the best corrected visual acuity (BCVA) were measured 1 day after the injection and compared with immediate pre-injection values. RESULTS: There were 79 eyes (57 patients) including 51 eyes with DME, 18 with branch retinal vein occlusion edema (BRVO-ME), and 10 eyes with central retinal vein occlusion edema (CRVO-ME). The intravitreal agents were triamcinolone acetonide (TA)(n = 15), dexamethasone sustained release implant (DEX)(n = 22), ranibizumab (n = 19), and bevacizumab (n = 23). Statistically significant improvement in CRT was seen in all injection groups (p < 0.05) while improvement in mean BCVA was significant only in the TA group (p = 0.009). The mean change in CRT was maximum with steroids than with anti-VEGFs; viz. 159.47 µ in TA, 115.45 µ in DEX, 86.10 µ in ranibizumab, and 78.78 µ in bevacizumab group. Least amount of change was noted in the spongy type of macular edema (18.73 µ) while improvement in mean BCVA was statistically significant only in the cystoid group (p = 0.01). CONCLUSIONS: Comparatively, steroid agents showed better immediate response to therapy than anti-VEGFs. Maximum reduction in central retinal thickness was seen following triamcinolone acetonide injection. Cystoid edema showed better immediate response than spongy retinal thickening.

Quantitative analysis of retinal microvascular changes in prediabetic and diabetic patients.

PURPOSE: To evaluate and correlate retinal microvascular changes in prediabetic and diabetic patients with functional and systemic parameters. METHODS: Optical coherence tomography angiography (OCTA) was performed on all subjects after medical evaluation and laboratory investigations for blood sugar, glycosylated hemoglobin, and others. Automated quantification of vascular indices of the superficial plexus were analyzed. RESULTS: Hundred and eleven persons (222 eyes) were grouped into prediabetic (PDM) (60 eyes), diabetic without retinopathy (NDR) (56 eyes), diabetic with retinopathy (DR) (66 eyes), and healthy controls (CTR) (40 eyes). The superficial retinal capillary plexus showed no significant changes in the prediabetic and NDR groups; however, central foveal thickness (CFT) was significantly reduced in PDM (P = 0.04). The circularity of the foveal avascular zone (FAZ) (P = 0.03) and the vessel density (VD) (P = 0.01) showed significant reduction from PDM to NDR. All vascular parameters were significantly reduced in DR and correlated with disease severity. The CFT correlated significantly with FAZ area. The VD and perfusion density were seen to correlate significantly with HbA1c and contrast sensitivity. The visual acuity was significantly correlated with the FAZ. Logistic regression revealed VD [OR 20.42 (7.9-53)] and FAZ perimeter [OR 9.8 (4.2-23.2)] as the strongest predictors of DR. CONCLUSION: The changes in OCTA can help predict onset of DR. FAZ changes are seen in early stages and are correlated well with systemic parameters, making it an easy target to monitor and screen for severity of DR. Significant reduction in the CFT in PDM suggests that neuronal damage precedes vascular changes.

Early structural and functional neurovascular changes in the retina in the prediabetic stage.

PURPOSE: This study was undertaken to investigate the neurovascular changes in the retina of prediabetic subjects. METHODS: Subjects enroled in a prospective study were separated into prediabetic and normal control groups based on their glycosylated haemoglobin (HbA1C) levels, fasting and postprandial blood sugar levels and glucose tolerance test. All the subjects underwent detailed ophthalmic evaluation, which included fundus examination, fundus photography, optical coherence tomography angiography (OCTA), and multifocal electroretinogram (mfERG). Comparisons were done between the groups using the Wilcoxon signed rank test. RESULTS: The median age was 48 years for the normal controls (n = 40), and 49.5 years for prediabetic subjects (n = 45) (p = 0.306). There was no difference in the vision, contrast sensitivity, thickness of the ganglion cell complex or the foveal avascular zone parameters between the groups. But the central foveal thickness and subfoveal choroidal thickness were significantly reduced in prediabetics (p < 0.01). The mfERG showed significant differences in the amplitude. The average amplitude was 35 ± 12 nv/deg2 in the normals and 29 ± 11 nv/deg2 in the prediabetics (p = 0.003). A weak positive correlation was noted between the mfERG and vascular parameters in the prediabetic group. CONCLUSIONS: The prediabetic stage reveals earliest functional neuronal changes in the retina. The neuronal function seems to be affected much earlier than clinically appreciable structural changes in the ganglion cell complex and precedes vascular changes in the retina.

Efficacy and safety of intravitreal dexamethasone implant in treatment naïve eyes with diabetic macular edema: Real world experience.

PURPOSE: To evaluate the efficacy and safety of intravitreal dexamethasone implant in treatment naïve eyes with diabetic macular edema (DME). METHODS: A retrospective analysis of treatment naïve eyes with DME which received intravitreal dexamethasone implant between January 2016 and March 2018 was done. Demographic details of the patients, ocular examination findings at baseline and on follow up visits were noted. Morphological features of DME and central macular thickness were noted on optical coherence tomography at each visit. The details regarding additional treatment for macular edema on follow up were noted. RESULTS: Sixty five eyes were included in the study. The mean age was 59.14 ± 9.59 years. The follow up ranged from 6 to 48 months. Psuedophakic eyes showed visual improvement whereas the phakic eyes showed stable vision. The central foveal thickness showed significant reduction (p = 0.05) in all the eyes. The best corrected visual acuity at final follow up (+0.65 logMAR) was slightly less as compared to baseline (+0.62 logMAR). Retreatment was needed in 37% eyes and antiglaucoma medications in 8% eyes. Cataract progression was noted in 24 eyes (37%); 17 eyes (26.1%) underwent surgery. Notably, 27 eyes (41.5%) had some degree of macular ischemia at baseline. And five eyes (7.7%) showed progression of retinopathy leading to vitreous hemorrhage. CONCLUSION: Dexamethasone implant is helpful in reducing the macular thickness and stabilizing the vision in treatment naïve DME; requiring less number of treatment sessions. However, it does not prevent progression of diabetic retinopathy. The visual improvement may be affected by cataract and macular ischemia.

Macular function assessment by multifocal electroretinogram and microperimetry in macular hole and correlation with visual acuity.

BACKGROUND: Functional outcome of macular hole (MH) surgery can be better assessed with multifocal electroretinogram (mfERG) and microperimetry (MP). It might provide better assessment than the Snellen visual acuity alone. OBJECTIVES: To evaluate macular function with mfERG and microperimetry, and assess their correlation with visual acuity in MH. MATERIALS AND METHODS: A prospective study was done in patients with unilateral,idiopathic full thickness MH. Standard surgery with vitrectomy, internal limiting membrane peeling and gas tamponade was done. Snellen and logMAR visual acuity, mfERG, microperimetry and optical coherence tomography were done pre and postoperatively. RESULTS: Twenty six patients with unilateral macular hole and twenty five age matched controls were included. The mean age of patients was 59.92±9.39 years (range: 40 to 74 years). All the holes were closed after surgery (two required second surgery). The mean visual acuity improved from 0.77±0.34 logMAR to 0.43±0.36 (p =0.03). The mfERG amplitudes differed ring wise, but the average amplitude changed from 26.31±8.82 to 20.52±7.11 (p =0.03). The mean retinal sensitivity changed from 12.98±2.59 to 13.42±2.53 (p =0.11). There was significant correlation between visual acuity and mfERG amplitudes and retinal sensitivity. Regression equations to predict visual outcome could be derived. CONCLUSIONS: In MH, mfERG and microperimetry show reduced responses, delay in recovery of function. They show a strong correlation with visual acuity. It is possible to predict vision after surgery with the help of mfERG and MP. Improved ability to predict visual outcome can increase the utility of anatomic success predictors.

Vascular changes precede tomographic changes in diabetic eyes without retinopathy and improve artificial intelligence diagnostics.

The purpose of this study was to evaluate early vascular and tomographic changes in the retina of diabetic patients using artificial intelligence (AI). The study included 74 age-matched normal eyes, 171 diabetic eyes without retinopathy (DWR) eyes and 69 mild non-proliferative diabetic retinopathy (NPDR) eyes. All patients underwent optical coherence tomography angiography (OCTA) imaging. Tomographic features (thickness and volume) were derived from the OCTA B-scans. These features were used in AI models. Both OCT and OCTA features showed significant differences between the groups (P < .05). However, the OCTA features indicated early retinal changes in DWR eyes better than OCT (P < .05). In the AI model using both OCT and OCTA features simultaneously, the best area under the curve of 0.91 ± 0.02 was obtained (P < .05). Thus, the combined use of AI, OCT and OCTA significantly improved the early diagnosis of diabetic changes in the retina.

A multifocal electroretinography study to evaluate risk of developing macular hole in the fellow eye of patients suffering with unilateral macular hole.

BACKGROUND: Visual outcome of eyes has often been found to be unsatisfactory even after successful closure of a macular hole, owing to factors like persistent metamorphopsia, scotoma, and reduced sensitivity. Therefore, it becomes critical to evaluate and study the probability and risk of developing a macular hole in the fellow eyes of the patient. This study analyzed the multifocal electroretinographic responses to help predict the risk of macular hole development in fellow eyes. METHODS: In total 26 fellow eyes, 26 eyes with macular hole, and 50 eyes of 25 controls were enrolled prospectively. The retinal responses from the different rings were compared in the three groups. Optical coherence tomography was done to rule out macular pathology or vitreomacular traction in the fellow eyes. RESULTS: All the fellow eyes under observation showed significantly reduced mean amplitudes of retinal response densities, in all rings as compared with controls (31.45 ± 10.38 versus 48.87 ± 7.55, p = 0.00). Three of the fellow eyes developed a macular hole during the 24 months observation period. The prevalence of fellow eye involvement was 11.5%. Relative risk of developing macular hole in the fellow eye ranged from 25 to 75. CONCLUSION: All the fellow eyes, including those that did not develop a macular hole, showed significantly reduced responses on multifocal electroretinogram. This indicates that macular hole may not be a focal disease. It may have widespread functional deficit which is bilateral in nature and suggestive of a degenerative or ischemic insult.

Interchangeability of retinal perfusion indices in different-sized angiocubes: An optical coherence tomography angiography study in diabetic retinopathy.

Purpose: To evaluate the differences in vascular indices in different scan sizes of optical coherence tomography angiography (OCTA) images in normal persons versus persons with diabetic retinopathy. Methods: OCTA scans of diabetic patients and age-matched controls were performed by a single operator. Automated quantification of vascular indices of the superficial plexus was analyzed in two angiocubes of 3 × 3 mm and 6 × 6 mm, respectively. The agreement was analyzed with the intraclass correlation coefficient (ICC) and Bland-Altman plots. Results: Forty-eight eyes with DR, 36 eyes with no diabetic retinopathy (No DR), and 26 eyes of age-matched normals were scanned. The foveal avascular zone (FAZ) area and perimeter were highly reliable and interchangeable in both angiocubes of the healthy eyes (ICC 0.94, 0.75), No DR (ICC 0.92, 0.85), and DR eyes (ICC 0.97, 0.89). The vessel density (VD) and perfusion density (PD) showed excellent agreement in normal (ICC 0.89, 0.80) and No DR eyes (ICC 0.92, 0.81). But, only fair ICC was observed in DR eyes (0.56, 0.42). Conclusion: The FAZ area and perimeter showed excellent reproducibility. The macular perfusion parameters are not interchangeable despite automated estimation. The variability is more with changes in the vascular network like DR. This variability should be considered while comparing different scans.

Retinal vascular abnormalities in Sturge-Weber syndrome.

Sturge-Weber syndrome (SWS) includes facial, leptomeningeal and choroidal hemangioma. The retinal vasculature is essentially normal. Rare cases of retinal vascular tortuosity and arterio-venous malformations have been reported. We report two cases with rare concomitant retinal vascular abnormalities along with SWS. Both the patients had nevus flammeus, hemifacial hypertrophy, and choroidal hemangioma. In one case, retinal cavernous hemangioma was seen in the affected eye. The other case revealed retinal neovascularization secondary to proliferative diabetic retinopathy in the eye with choroidal hemangioma.

Enhanced S-cone syndrome: Clinical spectrum in Indian population.

PURPOSE: Enhanced S-cone syndrome (ESCS), a rare disorder, is often misdiagnosed as other forms of retinal degenerations, which have a poorer prognosis than ESCS. The aim of this study is to report the varied clinical features of ESCS and distinguish it from other similar disorders. METHODS: We retrospectively scrutinized the records of patients with confirmed diagnosis of ESCS and analyzed the findings. RESULTS: We included 14 patients (age range 4-39 years) who were confirmed to have ESCS according to pathognomonic electroretinography (ERG) showing reduced photopic, combined responses, and 30 Hz flicker with reduced L, M cone responses and supernormal S cone responses. The disease presented in the 1st decade with night blindness and was almost stationary or minimally progressive. Mid-peripheral fundus changes in form of nummular pigmentary alterations, yellow punctate lesions, and macular schisis were noted. The vision ranged from 6/6 to 6/36 with follow-up ranging from 1month to 22 years. CONCLUSION: ESCS shows varied clinical features ranging from unremarkable fundus to pigment clumping and atrophic lesions. It has good prognosis with patients mostly maintaining their vision. ERG is diagnostic. More awareness and knowledge about this entity can help to differentiate it from other forms of night blindness.

Visual rehabilitation using microperimetric acoustic biofeedback training in individuals with central scotoma.

BACKGROUND: Patients with central scotoma have poor fixation stability and poor visual acuity. Acoustic biofeedback training can be an effective way to train such patients to eccentrically fixate. This study analyses the mean retinal sensitivity, saccadic velocity, and fixation stability after acoustic biofeedback training and shows correlation with age and scotoma size. METHODS: Patients with irreversible central scotoma in both the eyes secondary to macular diseases were selected. After undergoing comprehensive low vision assessment, 19 patients who were willing were recruited for the acoustic biofeedback training to the better eye in 10 sessions, using the MP-1 Microperimeter. Mean retinal sensitivity, saccadic velocity, fixation stability before and after the acoustic biofeedback were recorded. RESULTS: There were 17 men and two women. Ages ranged from 19-94 years (mean 54.63 ± 24.66). The scotoma size ranged from four to 20 degrees. Ten patients had age-related macular degeneration, four had Stargardt disease, three had traumatic macular scar, two had scarred myopic choroidal neovascular membrane, and one had myopic macular degeneration. The vision improved from 1.06 ± 0.36 to 0.86 ± 0.33 logMAR (p < 0.0001). The mean retinal sensitivity improved from 2.1 ± 2.9 dB to 2.7 ± 3.1 dB (p = 0.01), with negative correlation with age (p = 0.01) and scotoma size (p = 0.02). Fixation stability improved with reduction in the bivariate contour ellipse area (p = 0.01). It showed negative correlation with age (p = 0.02) and scotoma size (p = 0.10). The saccadic velocity reduced from 0.34°/second to 0.26°/second but was not significant (p > 0.99). The majority (58 per cent) had their preferred retinal locus superior to the fovea. There was good agreement between bivariate contour ellipse area and MP-1 Microperimeter inbuilt fixation parameters. The effect was maintained at six months with slight reduction in fixation stability. CONCLUSION: Acoustic biofeedback can improve fixation behaviour, visual acuity and retinal sensitivity in patients with central scotoma. The results are better with younger age and smaller scotoma size.

Factors influencing the choice of low-vision devices for visual rehabilitation in Stargardt disease.

BACKGROUND: Stargardt disease is the most common cause of juvenile macular degeneration leading to early central visual loss. Dispensing of correct low-vision devices based on the residual visual function and specific visual requirements of a patient can result in a positive outcome. It is important to know the factors involved in the selection of these devices. This study was undertaken to assess these factors. METHODS: Patients with Stargardt disease referred to a low-vision clinic underwent evaluation of visual status, disease stage, visual requirements and lifestyle. They were evaluated for suitability for successful use of various low-vision devices. Their education level and occupation were noted. They were counselled regarding the proper use of the devices and lifestyle modifications. For patients with extensive use of computers, modifications related to contrast, font size and audio software were explained. RESULTS: Among the 97 patients in the study (age range 7-66 years, mean 23.7 ± 13.1), there were 49 (50.5 per cent) students, 36 (37.1 per cent) employed, eight (8.2 per cent) unemployed, and four (4.2 per cent) homemakers. Except for seven patients (7.2 per cent), all were literate, with education ranging from primary school to college graduation. The presenting visual acuity for distance was 0.10-1.47 (0.79 ± 0.28), and for near was N4-N40 (N9.95 ± 6.65). This acuity showed positive correlation with age (p < 0.0001, R2 = 0.16) and with magnification required (p < 0.0001, R2 = 0.26). Patients above 40 years preferred higher adds and half-eye glasses, whereas younger patients preferred dome magnifiers. The occupation also influenced the choice. Disease stage was seen to affect the choice with advanced stages requiring higher magnifiers (p = 0.03, R2 = 0.11). Duration of disease and the magnification of low-vision devices showed a positive correlation (p = 0.03, R2 = 0.049). CONCLUSIONS: Age, presenting visual acuity, disease stage, duration, education and occupation influenced the choice of low-vision devices in patients with Stargardt disease. However, they appear to be interdependent and a larger, controlled study is required to provide information on the individual effect.