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

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.

Acupuncture treatment for optic atrophy: A protocol for systematic review

BACKGROUND

Optic atrophy (OPA) is a very tricky disorder. Presently, no effective management is available for this condition. Previous studies have reported that acupuncture may be effective for the treatment of OPA. However, its effectiveness is still inconclusive. Thus, this study will aim to assess the effectiveness and safety of acupuncture for OPA.

METHODS

A comprehensive literature search for relevant studies will be performed from the databases of PUMBED, EMBASE, CINAHI, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Cochrane Library, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, and other literature sources from inception up to the present. No language limitations will be applied to all literature searches. We will consider all randomized controlled trials (RCTs) and case-controlled trials (CCTs) for assessing the effectiveness and safety of acupuncture for OPA. The primary outcomes include the rates of vision improvement and visual field improvement. The secondary outcomes consist of the increased visual field average sensitivity, pattern visual evoked potential (PVEP) amplitude, and shortened PVEP latency, as well as any expected and unexpected adverse reactions. Risk of bias assessment will be performed by Cochrane risk of bias for RCTs and Newcastle-Ottawa Scale for CCTs.

RESULTS

In this study, we will outline details of the aims and methods on the effectiveness and safety of acupuncture for the treatment of OPA.

CONCLUSION

The results of this study will summarize the most current evidence of acupuncture for the treatment of patients with OPA.

DISSEMINATION AND ETHICS

The results of this study are expected to be published on peer-reviewed journals. This is a literature-based study; therefore, no ethical approval is necessary.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019135785.

Dominant optic atrophy: updates on the pathophysiology and clinical manifestations of the optic atrophy 1 mutation

PURPOSE OF REVIEW

Review recent advances in clinical and experimental studies of dominant optic atrophy (DOA) to better understand the complexities of pathophysiology caused by the optic atrophy 1 (OPA1) mutation.

RECENT FINDINGS

DOA is the most commonly diagnosed inherited optic atrophy, causing progressive bilateral visual loss that begins early in life. During the past 25 years, there has been substantial progress in the understanding of the clinical, genetic, and pathophysiological basis of this disease. The histopathological hallmark of DOA is the primary degeneration of retinal ganglion cells, preferentially in the papillomacular bundle, which results temporal optic disc pallor and cecocentral scotomata in patients with DOA. Loss of OPA1 protein function by OPA1 gene mutations causes mitochondrial dysfunction because of the loss of mitochondrial fusion, impaired mitochondrial oxidative phosphorylation, increases in reactive oxygen species, and altered calcium homeostasis. These factors lead to apoptosis of retinal ganglion cells by a haploinsufficiency mechanism.

SUMMARY

Improved understanding of the pathophysiology of DOA provides insights that can be used to develop therapeutic approaches to the DOA.

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.