Short Wavelength Automated Perimetry, Standard Automated Perimetry, and Optical Coherence Tomography in Dominant Optic Atrophy

Background: Blue-yellow axis dyschromatopsia is well-known in Autosomal Dominant Optic Atrophy (ADOA) patients, but there were no data on the correlation between retinal structure and short-wavelength automated perimetry (SWAP) values in this pathology. Methods: In this cross-sectional case-control study, we assessed the correlation between best corrected visual acuity (BCVA), standard automated perimetry (SAP), SWAP, and optical coherence tomography (OCT) parameters of 9 ADOA patients compared with healthy controls. Correlation analysis was performed between BCVA, mean deviation, pattern standard deviation (PSD), and fovea sensitivity (FS) values and the OCT thickness of each retinal layer and the peripapillary retinal nerve fiber layer (pRNFL). Results: The following significant and strong correlations were found: between BCVA and ganglion cell layer (GCL) and the global (G) pRNFL thicknesses; between SAP FS and GCL and the G-pRNFL thicknesses; between SWAP PSD and total retina, GCL, inner plexiform layer, inner nuclear layer, inner retinal layer and the temporal pRNFL thicknesses. We found a constant shorter duration of the SITA-SWAP compared with the SITA-STANDARD strategy. Conclusions: SWAP, SAP, and BCVA values provided relevant clinical information about retinal involvement in our ADOA patients. The perimetric functional parameters that seemed to correlate better with structure involvement were FS on SAP and PSD on SWAP.

Human retinal organoids with an OPA1 mutation are defective in retinal ganglion cell differentiation and function

Autosomal dominant optic atrophy (ADOA), mostly caused by heterozygous OPA1 mutations and characterized by retinal ganglion cell (RGC) loss and optic nerve degeneration, is one of the most common types of inherited optic neuropathies. Previous work using a two-dimensional (2D) differentiation model of induced pluripotent stem cells (iPSCs) has investigated ADOA pathogenesis but failed to agree on the effect of OPA1 mutations on RGC differentiation. Here, we use 3D retinal organoids capable of mimicking in vivo retinal development to resolve the issue. We generated isogenic iPSCs carrying the hotspot OPA1 c.2708_2711delTTAG mutation and found that the mutant variant caused defective initial and terminal differentiation and abnormal electrophysiological properties of organoid-derived RGCs. Moreover, this variant inhibits progenitor proliferation and results in mitochondrial dysfunction. These data demonstrate that retinal organoids coupled with gene editing serve as a powerful tool to definitively identify disease-related phenotypes and provide valuable resources to further investigate ADOA pathogenesis and screen for ADOA therapeutics.

Expanding SPG7 dominant optic atrophy phenotype: Infantile nystagmus and optic atrophy without spastic paraplegia

Spastic paraplegia is a neurodegenerative disorder characterized by progressive leg weakness and spasticity due to degeneration of corticospinal axons. SPG7 encodes paraplegin, and pathogenic variants in the gene cause hereditary spastic paraplegia as an autosomal recessive trait. Various ophthalmological findings including optic atrophy, ophthalmoplegia, or nystagmus have been reported in patients with spastic paraplegia type 7. We report a 15-year-old male patient with a novel heterozygous variant, c.1224T>G:p.(Asp408Glu) in SPG7 (NM_003119.3) causing early onset isolated optic atrophy and infantile nystagmus prior to the onset of neurological symptoms. Therefore, SPG7 should be considered a cause of infantile nystagmus with optic atrophy.

Vision-related quality of life and visual ability in patients with autosomal dominant optic atrophy

PURPOSE

The purpose of the study was to evaluate vision-related quality of life and visual ability in patients with OPA1 autosomal dominant optic atrophy (ADOA).

METHODS

This cross-sectional, observational study included 145 participants with a mutation in the OPA1 gene associated with ADOA, 63 mutation-free first-degree relatives and 92 healthy subjects unrelated to the families. Participants underwent a clinical eye examination, and adult participants completed the National Eye Institute Visual Function Questionnaire (NEI-VFQ-39), while children completed the Cardiff Visual Ability Questionnaire for Children (CVAQC).

RESULTS

In adults with ADOA, both mean visual acuity (VA) and mean contrast sensitivity (CS) were significantly inferior to both first-degree relatives and unrelated controls (p < 0.001). In children with ADOA, mean VA was significantly lower compared with first-degree relatives (p = 0.0052), whereas CS was not (0.127). Adults with ADOA scored lower than both comparator groups on composite score (p < 0.001), general health subscale (p = 0.0075) and all vision-related subscales (p < 0.001) except the ocular pain subscale (p = 0.2). In children with ADOA, the median CVAQC logit score was significantly lower compared with first-degree relatives (p = 0.037). The science lessons subscale was significantly lower for children with ADOA compared with first-degree relatives (p = 0.046), as well as the language lessons subscale (p = 0.038). For adults, composite score and subscale scores were significantly associated with both VA, CS and fixation status.

CONCLUSION

OPA1 mutation is associated with lower quality of life and visual ability in patients with ADOA compared with both first-degree relatives and unrelated controls. VA, CS and fixation status affect quality of life in patients with ADOA.

Optical coherence tomography angiography in the multimodal assessment of the retinal posterior pole in autosomal dominant optic atrophy

PURPOSE

To assess retinal vascular involvement in patients with autosomal dominant optic atrophy (ADOA) genetically confirmed by the presence of the OPA1 (Optic Atrophy 1) gene mutation using a multimodal protocol of investigation of retinal posterior pole.

METHODS

In this cross-sectional, case-control, observational study, both eyes of 13 patients with a genetic diagnosis of ADOA were compared with both eyes of 13 healthy controls (HCs). All subjects underwent full ophthalmological examination, spectral domain-optical coherence tomography (SD-OCT), fundus perimetry (FP) and OCT angiography (OCTA).

RESULTS

Vessel density (VD) of the superficial and deep macular vascular plexi and of the radial peripapillary capillary plexus were significantly decreased (p ≤ 0.001) in ADOA patients compared with HCs. The area under the receiver operating characteristics analysis also revealed high values of sensitivity and specificity of OCTA parameters in distinguish between patients and HCs. A strong correlation (Pearson Coefficient, r = 0.91) emerged between OCTA VD of the superficial retinal plexus and the average Ganglion Cell Layer (GCL) thickness as measured by SD-OCT; a slightly lower correlation (Pearson Coefficient, r = 0.89) was also found between VD of the deep plexus and the average GCL thickness of the same eyes in patients with ADOA. The correlation among values of differential light sensitivity (DLS) measured by FP with VD and GCL thickness parameters was also investigated. The correlation analysis among DLS and the VD parameters showed from low-to-moderate correlation (ranging from r = 0.29 for the deep fovea VD to r = 0.59 for the deep whole image VD). The correlation coefficient between the mean DLS and the average thickness of GCL was more significant (Pearson Coefficient, r = 0.75). A significant correlation emerged also between the VD and the visual acuity, in terms of LogMAR BCVA (best-corrected visual acuity), especially for the VD of the deep capillary plexus (Pearson Coefficient for the Deep whole Image VD and LogMAR BCVA r = -0.75; for the Deep parafovea VD and LogMAR BCVA r = -0.78).

CONCLUSION

Retinal microvascular assessment by OCTA angiography can provide relevant clinical information on retinal involvement in ADOA patients. In patients with genetically confirmed OPA1-related ADOA, there is a decrease in retinal vessel density associated with GCL thinning and DLS reduction.

Genetic Spectrum and Characteristics of Hereditary Optic Neuropathy in Taiwan

Hereditary optic neuropathy (HON) is a group of genetically heterogeneous diseases that cause optic nerve atrophy and lead to substantial visual impairment. HON may present with optic nerve atrophy only or in association with various systemic abnormalities. Although a genetic survey is indispensable for diagnosing HON, conventional sequencing techniques could render its diagnosis challenging. In this study, we attempted to explore the genetic background of patients with HON in Taiwan through capture-based next-generation sequencing targeting 52 HON-related genes. In total, 57 patients from 48 families were recruited, with 6 patients diagnosed as having Leber hereditary optic neuropathy through initial screening for three common variants (m.3460G>A, m.11778G>A, m.14484T>C). Disease-causing genotypes were identified in 14 (33.3%) probands, and OPA1 variants were the most prevalent cause of autosomal HON. Exposure to medications such as ethambutol could trigger an attack of autosomal dominant optic atrophy. WFS1 variants were identified in three probands with variable clinical features in our cohort. Hearing impairment could occur in patients with OPA1 or WFS1 variants. This is the first comprehensive study investigating the genetic characteristics of HON in Taiwan, especially for autosomal HON. Our results could provide useful information for clinical diagnosis and genetic counseling in this field.

Associations between OPA1, MFN1, and MFN2 polymorphisms and primary open angle glaucoma in Polish participants of European ancestry

BACKGROUND

Glaucomatous optic nerve damage is caused by selective death of retinal ganglion cells (RGCs). Another condition with underlying loss of RGCs is autosomal dominant optic atrophy (ADOA). Majority of ADOA patients have mutations in OPA1, gene responsible for mitochondrial fusion final steps. Clinical resemblance between the two diseases make genes involved in mitochondrial fusion good candidates as glaucoma genes. In this study, we investigated if selected polymorphisms of OPA1, MFN1, and MFN2 were associated with glaucoma in Polish population.

METHODS

Four OPA1 (rs166850, rs10451941, rs7624750, rs9851685), one MFN1 (rs2111534), and two MFN2 (rs873458, rs2295281) single nucleotide polymorphisms were investigated in 304 primary open angle glaucoma patients (204 with normal tension glaucoma, 100 with high-tension glaucoma) and 258 control subjects using RT-PCR method.

RESULTS

There was a significant difference in genotype frequencies of rs9851685 and rs2111534 polymorphisms between glaucoma patients and control subjects. Several genotype combinations comprising SNPs at OPA1 and MFN1 were significantly differently distributed in a three-way comparison between controls, patients with NTG and patients with HTG. None of the studied MFN2 polymorphisms was significantly associated with HTG or NTG.

CONCLUSIONS

In studied population, genotype CC and allele C of rs9851685 OPA1 polymorphism are NTG risk factors, whereas TT genotype and T allele of this polymorphism are protective factors against NTG. Genotype GA of rs2111534 MFN1 polymorphism is an HTG risk factor and AA genotype of this polymorphism is a protective factor against HTG. Several OPA1 and MFN2 genotype combinations are significantly associated with either increased or decreased risk of glaucoma in this population.

Colour-centred Release Hallucinations in a Patient with Early Parkinson's Disease and Unrecognised Autosomal Dominant Optic Atrophy

Visual hallucinations in Parkinson's disease (PD) are usually attributed to medications and dysfunction in higher order sensory processing as the disease progresses. However deficits in visual processing, including colour discrimination, have been reported in early, untreated PD and it is unclear how these, along with co-morbid conditions affecting vision, could contribute to hallucinations. This case describes a 66-year-old otherwise fully independent woman with early, mild PD who presented with discrete episodes of unusual vivid hallucinations centred on colour. She was later found to have a subclinical colour deficiency in excess of her PD and, after reporting a lifelong history of poor vision in her father, tested positive for autosomal dominant optic atrophy. This case illustrates how a lifelong extrinsic deficiency in colour vision can interact with the effects of visual changes in early stage PD and medication to provoke colour hallucinations. It therefore emphasises the importance of full ophthalmological work up in similar cases where hallucinations are atypical and unexpected for the severity and stage of PD.

Mutation Screening of mtDNA Combined Targeted Exon Sequencing in a Cohort With Suspected Hereditary Optic Neuropathy

Purpose

Leber hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (ADOA) are the two commonest forms of hereditary optic neuropathy. The aim of this study was to comprehensively investigate the incidence and spectrum of mutations in patients with suspected hereditary optic neuropathy by combining mitochondrial DNA (mtDNA) genome-wide and targeted exon sequencing.

Methods

A cohort of 1101 subjects were recruited to participate in the study, comprising 177 families (177 probands and their family members, a total of 537 subjects, including 254 patients) and 164 sporadic cases with suspected hereditary optic neuropathy, and 400 unrelated control subjects for genetic analysis: all subjects (including control subjects) underwent a comprehensive ophthalmologic examination and were subjected to sequencing analysis of mtDNA genome-wide and targeted exon. Overall, targeted exon sequencing was used to screen 792 genes associated with common hereditary eye diseases, and the mtDNA genome-wide were screened by next-generation sequencing.

Results

We found variants detected in 168 (40.2%, 168/418) of the 418 patients screened. Among these, 132 cases (78.6%, 132/168) were detected with known LHON disease-causing mtDNA variants; 40 cases (23.8%, 40/168) were detected with nuclear DNA (ntDNA) variants, which included 36 cases (21.4%, 36/168) with detected OPA1 mutations, 4 patients (2.4%, 4/168) with detected OPA3 mutations, and 2 patients (1.2%, 2/168) with detected TMEM126A homozygous mutation. Coexistence variation (mtDNA/mtDNA [n = 16], ntDNA/ntDNA [n = 4], mtDNA/ntDNA [n = 7]) was found in 27 patients (16.4%, 27/165), including mtDNA/ntDNA coexistence variation that was detected in seven patients. Among these ntDNA mutations, 38 distinct disease-causing variants, including autosomal recessive heterozygous mutations, were detected, which included 22 novel variants and two de novo variants. Total haplogroup distribution showed that 34.5% (29/84) and 28.6% (24/84) of the affected subjects with m.11778G>A belonged to haplogroup D and M, with a high frequency of subhaplogroups D4, D5, and M7.

Conclusions

The LHON-mtDNA mutations are the commonest genetic defects in this Chinese cohort, followed by the OPA1 mutations. To our knowledge, this is the first comprehensive study of LHON, ADOA, and autosomal recessive optic atrophy combined with mtDNA genome-wide and targeted exon sequencing, as well as haplogroup analysis, in a large cohort of Chinese patients with suspected hereditary optic neuropathy. Our findings provide a powerful basis for genetic counseling in patients with suspected hereditary optic neuropathy.

Translational Relevance

We applied mtDNA genome-wide sequencing combined with panel-based targeted exon sequencing to explore the pathogenic variation spectrum and genetic characteristics of patients with suspected hereditary optic neuropathy, providing a comprehensive research strategy for clinical assistant diagnosis, treatment, and genetic counseling.

Thickness mapping of individual retinal layers and sectors by Spectralis SD-OCT in Autosomal Dominant Optic Atrophy

PURPOSE

To assess layer- and location-specific retinal thickness deficits in autosomal dominant optic atrophy (ADOA) using Spectralis SD-OCT.

METHODS

This cross-sectional study included 41 ADOA patients with OPA1 exon 28 (2826delT) mutation [age, 8.6-83.5 years; best-corrected visual acuity (BCVA), 8-89 Early Treatment Diabetic Retinopathy Study (ETDRS) letters] and 55 mutation-free first-degree relatives as healthy controls (age, 8.9-68.7; BCVA, 80-99). Participants underwent routine examination and optical coherence tomography (OCT) with segmentation of the whole retina, inner retinal layers (IRL) and outer retinal layers (ORL). Individual segmentation was performed of the perifoveal retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retinal pigment epithelium (RPE) and the peripapillary RNFL. Combinations of layers and sectors were tested for their diagnostic significance. Only right eye data are presented. Statistical analysis was adjusted for age, gender, spherical equivalent, axial length and family clustering in a mixed model analysis.

RESULTS

The perifoveal RNFL, GCL, IPL and the peripapillary RNFL were all significantly thinner in ADOA patients than in healthy controls (p < 0.0001). No statistical difference was found for other layers. The most prominent and diagnostically most valuable deficit was found in the GCL (-49.9%) in the 'nasal inner macula' (NIM) sector (-63%). Attenuation of the peripapillary RNFL was most significant in the temporal sector (-58.4%).

CONCLUSION

In ADOA, retinal ganglion cells are most prominently reduced in the nasal perifoveal area of the GCL, which together with the temporal peripapillary RNFL area serves as the strongest diagnostic OCT marker.

The reduction of temporal optic nerve head microcirculation in autosomal dominant optic atrophy

PURPOSE

To evaluate the optic nerve head (ONH) microcirculation in autosomal dominant optic atrophy (ADOA) patients.

METHODS

This study comprised 22 eyes of 12 ADOA patients, diagnosed according to clinical findings including family history and the presence of mutations in the OPA1 gene. Twenty-four normal eyes of 24 age-matched subjects, with either the right or left eye randomly selected for use, served as controls. Circumpapillary retinal nerve fibre layer thickness (cpRNFLT) and mean blur rate (MBR) in the ONH were determined with optical coherence tomography (OCT) and laser speckle flowgraphy (LSFG), respectively. For each ONH quadrant (superior, temporal, inferior and nasal), the MBR and cpRNFLT ratio was also calculated by dividing tissue MBR in that quadrant by tissue MBR in the entire ONH and by dividing cpRNFLT in that quadrant by cpRNFLT in the entire ONH respectively.

RESULTS

Mean blur rate (MBR) in all quadrants was significantly lower in the ADOA patients than in the controls (p < 0.001 in each). The MBR ratio was significantly lower in the ADOA patients only in the temporal quadrant (p < 0.001). Similarly, cpRNFLT was lower in the ADOA patients in all quadrants (p < 0.001 in each), and the cpRNFLT ratio was lower in the temporal quadrant (p < 0.001).

CONCLUSION

Reduced blood flow in the temporal optic disc in ADOA patients is associated with reduced temporal cpRNFLT, suggesting that both are caused by damage to the papillomacular bundle. The anatomical characteristics of the papillomacular bundle may make it especially susceptible to mitochondrial dysfunction-induced damage, which occurs in ADOA.

Dissociation of Pupillary Post-Illumination Responses from Visual Function in Confirmed OPA1 c.983A > G and c.2708_2711delTTAG Autosomal Dominant Optic Atrophy

Purpose: To test whether the melanopsin-containing, intrinsically photosensitive retinal ganglion cells (ipRGCs), as evaluated by examination of the pupillary light reflex (PLR), are preserved in genetically confirmed autosomal dominant optic atrophy (ADOA).

Method: Twenty-nine patients with either the c.983A > G (n = 14) or the c.2708_ 2711delTTAG mutation (n = 15) were examined with monochromatic pupillometry, using isoluminant (300 cd/m²), red (660 nm) or blue (470 nm) light, optical coherence tomography, automated visual field analysis, and with determination of best corrected visual acuity (BCVA). Since we examined two different mutations, initially we compared all outcome variables between the two, and finding no statistically significant difference, pooled them.

Results: Despite a poor BCVA (56 letters, ETDRS) in the ADOA patients, their post-illuminatory pupil responses did not differ significantly from those of healthy controls (blue, p = 0.45, red, p = 0.49, t-test), and no statistically significant effect was noted of peripapillary retinal nerve fiber layer thickness, ganglion cell-inner plexiform layer thickness, or age.

Conclusion: The PLR to blue light of high luminance (300 cd/m²) was preserved in both c.983A > G and c.2708_2711delTTAG ADOA despite severe visual loss and optic nerve atrophy. The study confirms, in a large sample of two genetically homogenous groups, that the ipRGCs are spared in ADOA.

Retinal vessel diameters decrease with macular ganglion cell layer thickness in autosomal dominant optic atrophy and in healthy subjects

PURPOSE

To investigate retinal trunk vessel diameters in subjects with autosomal dominant optic atrophy (ADOA) and mutation-free healthy relatives.

METHODS

This cross-sectional study included 52 ADOA patients with the optic atrophy 1 (OPA1) exon 28 (c.2826_2836delinsGGATGCTCCA) mutation (age 8.6-83.5 years) (best-corrected visual acuity (BCVA) 8-94 Early Treatment Diabetic Retinopathy Study (ETDRS) letters) and 55 mutation-free first-degree healthy relatives (age 8.9-68.7 years, BCVA 80-99). Analysis of fundus photographs provided integrated magnification-corrected measures of retinal vessel diameters (central retinal artery equivalent, CRAE, and central retinal vein equivalent, CRVE). Statistical analysis was corrected for age, gender, spherical equivalent refraction, axial length and mean arterial blood pressure (MABP) in a mixed model analysis.

RESULTS

Retinal arteries and veins were thinner in ADOA than in healthy controls (CRAE (mean ± 2 standard deviations (SD)) 153.9 ± 41.0 μm and CRVE 236.1 ± 42.0 μm in ADOA, CRAE 172.5 ± 25.0 μm (p = 0.0004) and CRVE 254.2 ± 37.6 μm (p = 0.0019) in healthy controls). MABP was comparable in the two groups (p = 0.18), and in both groups, CRAE decreased with increasing MABP (p = 0.01 and p < 0.0001, respectively). In ADOA, CRAE and CRVE decreased with age (p = 0.011 and p = 0.020, respectively) and CRAE decreased with decreasing BCVA (p = 0.011). In patients with ADOA and in healthy controls, CRAE decreased with decreasing average macular ganglion cell-inner plexiform layer (GC-IPL) thickness (p = 0.0017 and p = 0.0057, respectively).

CONCLUSION

Narrow retinal arteries and veins were associated not only with the severity of ADOA but with ganglion cell volume in patients with ADOA and in healthy subjects. This suggests that narrow vessels are a consequence rather than the cause of inner retinal hypoplasia or atrophy, although longitudinal studies are needed to confirm this hypothesis.

Optic disc morphology of patients with OPA1 autosomal dominant optic atrophy

BACKGROUND/AIMS

Patients with autosomal dominant optic atrophy (ADOA) are genetically heterogeneous, but all have disc pallor. A degree of cupping in ADOA can make the distinction from normal tension glaucoma (NTG) clinically difficult. This study aimed to clarify the features of the optic nerve of patients with ADOA at the OPA1 locus.

METHODS

29 patients (58 eyes), from 12 families, were identified in a prospective observational study of patients with ADOA examined by a single observer between 1995 and 1998, in whom genetic analysis showed either evidence for linkage to chromosome 3q28 or mutations in the ADOA gene, OPA1. All of the patients had disc and fundal photographs available for retrospective analysis. Clinical data collected included disc appearance, intraocular pressure, Snellen visual acuity, Hardy-Rand-Rittler colour vision plates, and Humphrey 30-2 visual fields.

RESULTS

Mean age at time of examination was 37 years and mean visual acuity was 6/24. Disc morphology showed temporal disc pallor in 30 eyes (52%) and total disc pallor in 28 eyes (48%). At least one disc showed a cup to disc ratio of more than 0.5 in 18 patients (28 discs, 48%). The temporal neuroretinal rim always showed pallor and shallow shelving (or saucerisation) was seen in 46 eyes (79%). Only 12 discs (21%) had deep excavation and baring of blood vessels. All of the patients had normal intraocular pressure and no family history of glaucoma. There was a temporal grey, pigmentary crescent in 12 patients (18 eyes, 31%) and peripapillary atrophy in 20 patients (40 eyes, 69%), but disc margin haemorrhages were not seen. There was no maculopathy or retinopathy.

CONCLUSION

The optic disc morphology, described for the first time in this genetically homogeneous population of patients with OPA1 ADOA, shows a distinctive absence of a healthy neuroretinal rim and shallow saucerisation of the optic disc cup, with frequent peripapillary atrophy.