Approach to inherited retinal diseases

Inherited retinal diseases (IRDs) are a group of phenotypically diverse disorders with varied genetic mutations, which result in retinal degeneration leading to visual impairment. When a patient presents to a clinician who is not an IRD expert, establishing a correct diagnosis can be challenging. The patient and the family members are often anxious about further vision loss. They are eager to know the prognosis and chance of further worsening of the vision. It is important for every eye specialist to educate himself/herself about the basics of IRD. It would help to familiarize oneself about how to approach a patient with an IRD. An early and accurate diagnosis can help predict the vision loss and also help the patient plan his/her education and choose appropriate career choices. An updated knowledge about the genetic mutations, mode of inheritance, and possible therapies would empower the eye specialist to help his/her patients. This article gives a broad plan of how to approach a patient with IRD with regards to characterization and diagnosis of the disorder, visual rehabilitation, and possible therapy.

Structural and functional phenotypic features and molecular analysis of Indian patients with Bietti crystalline dystrophy

Purpose:

Bietti crystalline dystrophy (BCD) is a rare retinal dystrophy, uncommon in Indians. This study describes the various phenotypic features seen in the Indian population.

Methods:

In this retrospective, descriptive case series, records of patients with either clinical or molecular diagnosis of BCD from 2009 to 2020 were perused. Phenotypic and genotype information was collected and analyzed.

Results:

This study included 58 patients of BCD (31 males) aged 21–79 years (mean: 47 ± 14 years). The age at onset ranged from 7 to 41 years (mean: 28.8 ± 5.1 years). Vision ranged from 20/20 to counting fingers. There were 18 (31%) patients with stage 1 with crystals and mild retinochoroidal atrophy, 22 (38%) with stage 2 with atrophy extending beyond arcades, and 18 (31%) with absent crystals and extensive atrophy of stage 3. Choroidal neovascular membrane was seen in four patients. The optical coherence tomography showed retinochoroidal thinning (84.6%), outer retinal tubulations (71.8%), and paradoxical foveal thickening with interlaminar bridges (7.7%). Electrophysiology and visual fields showed reduced responses in advanced retinochoroidal changes. Molecular confirmation was available in five patients; five mutations were seen in the CYP4V2.

Conclusion:

A wide variation is seen in the phenotypic picture of BCD. A molecular diagnosis is helpful in differentiating from other retinal dystrophies. The OCT shows the peculiar feature of the interlaminar bridge in early cases with photoreceptor loss. Further investigations into this OCT feature may provide insights into the pathogenesis of BCD. A genotype–phenotype correlation could not be done.

Diagnosis and Management of Post Traumatic Recurrent Unilateral Accommodative Spasm-A Case Report

Spasm of accommodation refers to constant contraction of the ciliary muscles of the eye, which fail to relax. Neurological issues, head injury, and psychogenic factors can lead to spasm of accommodation, which is generally bilateral. This case report describes the clinical presentation of traumatic, unilateral accommodative spasm in an army person. A 26-year-old male presented with complaints of diminution of near vision in the left eye noticed accidentally. History revealed a blunt injury in the eyebrow region of the left eye two months back. His best corrected visual acuity was 6/6, 0.8 M (N6) in the right eye and 6/9, 2.5 M (N18) in the left eye. Accommodative response was documented using an open-field autorefractometer that showed asymmetry in the accommodation response and pupillary diameter between the two eyes. One percent Atropine sulfate eye ointment - twice a day for 3 days - was prescribed. On the fourth day, the spasm was resolved in the left eye. Pre- and post-Atropine administration, lens thickness measurements were documented, which showed significant changes. Accommodative facility exercise was initiated after the pharmacological management. Unilateral accommodative spasm is rare and needs careful investigations. Objective assessment of accommodative response and lens thickness measurement play a vital role in confirming the diagnosis.

Comparison Between Ranibizumab Biosimilar, Innovator Ranibizumab and Bevacizumab in a Real-World Situation

Introduction

To analyze the efficacy of biosimilar ranibizumab compared to innovator ranibizumab and bevacizumab.

Methods

We retrospectively analyzed consecutive patients treated with biosimilar ranibizumab for wet age-related macular degeneration (AMD) and macular edema (ME) (due to diabetes and vein occlusion) and compared them with ranibizumab- and bevacizumab-treated patients.

Results

Of 202 patients, 67 (33.2%) received biosimilar ranibizumab (BSR), 69 (34.2%) ranibizumab (RBZ) and 66 (32.7%) bevacizumab (BEV). All patients received three consecutive injections followed by pro re nata dosing. The follow-up ranged from 3 to 24 months. The mean numbers of injections were 6.68 for RBZ, 6.4 for BEV and 4.7 for BSR. At 3 months, nAMD (n = 115, 56.9%) and ME (n = 87, 43.1%) groups showed significant improvement in vision and central foveal thickness (CFT) across all three agents. After ≥ 6 months, the effects were maintained in the AMD group but not in the ME group. Maximum effect was seen at 1 month. At no point in time was a significant difference noted among the three anti-vascular endothelial growth factor (anti-VEGF) agents. No major safety concerns were noted.

Conclusions

Biosimilar ranibizumab is comparable to innovator ranibizumab and bevacizumab in efficacy and safety.

A Delphi method based consensus statement for surgical management of proliferative diabetic retinopathy in India

Purpose

To derive consensus statements for surgical management of proliferative diabetic retinopathy (PDR) for vitreoretinal (VR) surgeons.

Methods

Thirteen prolific VR surgeons representing all regions of India were invited to participate in a 42-point questionnaire based on the Delphi methodology describing various surgical scenarios commonly encountered in PDR. Consensus was derived using predefined robust analytics. Scenarios that returned a moderate consensus in round 1 were taken to round 2 as per the Delphi methodology. After considering all inputs, the final consensus criteria were developed.

Results

A strong consensus was derived about waiting for 4 weeks before considering vitrectomy. In treatment-naïve eyes with fresh vitreous hemorrhage (VH), the wait time was slightly shorter for extramacular tractional retinal detachment (2-4 weeks) and longer (4-6 weeks) for eyes treated previously with laser or anti-VEGF agents. The expert panel recommended using preoperative anti-VEGF only in eyes with large membranes requiring extensive dissection. For post vitrectomy VH, while a conservative approach was recommended for the first episode of VH, experts recommended immediate vitreous lavage for recurrent episodes of VH. In eyes with iris neovascularization, the panel recommended immediate anti-VEGF injection followed by early vitreous lavage in nonresponsive eyes. A strong consensus was derived for stopping antiplatelet agents before surgery, while there was only a moderate consensus for performing vitrectomy for recalcitrant macular edema unresponsive to anti-VEGF injections in the absence of traction.

Conclusion

This study provides valuable consensus on managing the different scenarios encountered during surgical management of PDR and should help guide the VR surgeons in clinical decision-making.

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.

Proteomics-based approach for differentiation of age-related macular degeneration sub-types

Purpose:

Age-related macular degeneration (AMD) is one of the leading causes of irreversible central vision loss in the elderly population. The current study aims to find non-invasive prognostic biomarkers in the urine specimens of the AMD patients.

Methods:

Peripheral blood and urine samples were collected from 23 controls and 61 AMD patients. Genomic DNA was extracted from the buffy coat of peripheral blood. Allele specific PCR was used to assay SNPs in complement factor H (CFH), complement component 3 (C3). Comparative proteomic analysis of urine samples from early AMD, choroidal neovascular membrane (CNVM), geographic atrophy (GA), and healthy controls was performed using isobaric labelling followed by mass spectrometry. Validation was performed using enzyme-linked immunosorbent assay (ELISA).

Results:

Comparative proteomic analysis of urine samples identified 751 proteins, of which 383 proteins were found to be differentially expressed in various groups of AMD patients. Gene ontology classification of differentially expressed proteins revealed the majority of them were involved in catalytic functions and binding activities. Pathway analysis showed cell adhesion molecule pathways (CAMs), Complement and coagulation cascades, to be significantly deregulated in AMD. Upon validation by ELISA, SERPINA-1 (Alpha1 antitrypsin), TIMP-1 (Tissue inhibitor of matrix metaloprotease-1), APOA-1 (Apolipoprotein A-1) were significantly over-expressed in AMD (n = 61) patients compared to controls (n = 23). A logistic model of APOA-1 in combination with CFH and C3 polymorphisms predicted the risk of developing AMD with 82% accuracy.

Conclusion:

This study gives us a preliminary data on non-invasive predictive biomarkers for AMD, which can be further validated in a large cohort and translated for diagnostic use.

Safety and efficacy of Razumab™ (world's first biosimilar ranibizumab) in wet age-related macular degeneration: a post-marketing, prospective ASSET study

Background

Razumab™ (world’s first biosimilar ranibizumab) is approved for several macular disorders including wet age-related macular degeneration (AMD). We evaluated the safety and efficacy of biosimilar ranibizumab in wet AMD.

Methods

This prospective, multicentre, rAnibizumab bioSimilar Safety Efficacy postmarkeTing (ASSET) study enrolled patients aged ≥ 50 years with wet AMD having best-corrected visual acuity (BCVA) between 20/40 and 20/320. The patients received intravitreal biosimilar ranibizumab 0.5 mg every 4 weeks for 24 weeks. Safety endpoints included the incidence of adverse events (AEs), serious AEs (SAEs), and immunoreactivity after 6 months. The efficacy endpoints were the proportion of patients who lose fewer than 15 letters, increase in BCVA, change in central retinal thickness (CRT), and change in Visual Function Questionnaire-25 (VFQ-25) score, from baseline to 24 weeks.

Results

Of the 126 enrolled patients, majority (95.24%) of the patients received all 6 doses of biosimilar ranibizumab (total 3 mg). Nineteen AEs were reported (n = 16; 12.7%); majority (78.9%) were mild. There were no serious AEs reported, except one AE of death which was unrelated to the study drug. None of the patients discontinued the study due to an AE. The most common ocular AE was increase in intraocular pressure (4 events) and non-ocular AE was pyrexia (5 events). A total of 7.9% (10/126) patients prior to dosing and 7.1% (9/126) patients post-treatment were positive for anti-ranibizumab antibodies. No AEs suggestive of immunogenicity were noted. At 24-weeks, 97.60% patients in the intent-to-treat (ITT) population (N = 125) and 97.41% patients in the per-protocol (PP) population (N = 116) lost < 15 letters from baseline visual acuity. In the ITT and PP populations, 31.20% and 32.76% patients, respectively, showed improved visual acuity by ≥ 15 letters. Significant improvements in BCVA (mean difference: 8.8, 9.2, p < 0.001 for ITT, PP) and VFQ-25 (8.5, 9.2, p < 0.001 for ITT, PP) were seen; CRT reduced significantly (125 µm, 119.3 µm, p < 0.001 for ITT, PP).

Conclusion

Razumab™ (world’s first biosimilar ranibizumab) was well-tolerated without new safety concerns and significantly improved visual acuity in wet AMD patients.

Trial registration CTRI/2016/03/006739. Registered 18 March 2016—Prospectively registered, http://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=13141&EncHid=&userName=2016/03/006739

Supplementary Information

The online version contains supplementary material available at 10.1186/s40942-021-00293-w.

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.

Multilayered retinal pigment epithelial detachment: an optical coherence tomography angiography perspective

A new entity termed multilayered pigment epithelial detachment is seen to occur with the use of multiple intravitreal anti-VEGF agents. A distinct appearance of a spindle-shaped elevation with bands of hyporeflective and hyperreflective tissue is seen on optical coherence tomography. We describe a novel finding on optical coherence tomography angiography which includes a large type 1 choroidal neovascular membrane underlying this elevation. A large vascular network is seen. It is thought to be protective in nature and may prevent further degeneration.

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.

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.

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.

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.

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.