Quantitative analysis of retinal microvascular changes in macular telangiectasia type 2 using optical coherence tomography angiography

Evaluation of Optic Disc, Retinal Vascular Structures, and Acircularity Index in Patients with Idiopathic Macular Telangiectasia Type 2

BACKGROUND

We aimed to compare the retinal, optic disc vascular density (ODVD) values, and acircularity index (AI) of patients with idiopathic macular telangiectasia type 2 (IMT) and healthy individuals using the optical coherence tomography angiography (OCTA) device.

METHODS

The study included 39 patients with IMT and 37 healthy controls. The OCTA findings of the patients and controls were examined.

RESULTS

The total, parafoveal and perifoveal vascular density of the superficial capillary plexus, choriocapillaris blood flow, inside-disc ODVD, retinal nerve fiber layer (RNFL), and retinal thicknesses were found to be statistically significantly lower, and the foveal avascular zone value was statistically significantly higher in the IMT group compared to the control group (p = 0.001, p = 0.01, p = 0.02, p = 0.01, p = 0.009, p = 0.002, p = 0.02, respectively). There was a statistically significant negative correlation between best-corrected visual acuity (BCVA) and AI (p = 0.02), and a statistically significant positive correlation between peripapillary vascular density and BCVA (p = 0.04).

CONCLUSIONS

We consider that the lower retinal, choriocapillaris, ODVD values, and retinal and RNFL thicknesses in the patients with IMT compared to the controls were due to vascular damage, remodeling, fibrosis, proliferation, and Müller cell damage. Ellipsoid zone defect, AI, and peripapillary vascular density are important indicators in the evaluation of visual acuity in these patients.

Use of OCT Angiography to Diagnose and Manage Atypical Presentations of Macular Telangiectasia Type 2

Macular telangiectasia Type 2 (MacTel) is a bilateral acquired retinal disease characterized by both vascular changes and atrophy of the retina. The purpose of this case series is to highlight the use of optical coherence tomography angiography (OCTA) as a non-invasive imaging modality to distinguish atypical MacTel from other macular conditions with similar presentations. We performed a retrospective review of patients referred to our academic retinal practice with unconfirmed or misdiagnosed MacTel between July 2017 and July 2021. Patients’ OCTA imaging findings were reviewed to guide the appropriate diagnosis and management of atypical MacTel. Fifteen eyes from eight patients were included in this study. Six patients were referred with previous diagnoses of either full-thickness macular hole, lamellar hole, vitreomacular traction (VMT), postoperative cystoid macular edema (CME), or diabetic macular edema (DME). Two patients were referred to us to confirm the diagnosis of MacTel. OCTA revealed telangiectatic vessels in the temporal parafovea of all 15 eyes. OCTA also highlighted previously undiagnosed subretinal neovascularization (SRNV) in seven eyes. OCTA imaging is a valuable imaging modality to distinguish MacTel from other macular conditions, whose treatment courses vary substantially. Due to its ease of use, it holds immense potential in the future as treatments for non-proliferative MacTel emerge.

Visual function correlates with foveal slope, retinal and choroidal thickness on optical coherence tomography in type 2 Macular Telangiectasia

PURPOSE

To correlate the foveal slope angle (FSA), retinal (RT) and choroidal (CT) thickness measured using optical coherence tomography (OCT) across different stages of type 2 macular telangiectasia (MacTel) with best-corrected visual acuity (BCVA).

METHODS

A cross-sectional study of 182 gradable quality macular OCT images of 49 patients with type 2 MacTel was carried out. RT was measured on the Spectralis OCT machine from ETDRS (Early Treatment Diabetic Retinopathy Study) retinal thickness map and later used for calculating FSA. RT and CT were measured at 500-µm intervals up to 1500 µm from foveal centre manually. The change in RT, CT and FSA across five stages of type 2 MacTel was assessed. The measurements were correlated with BCVA.

RESULTS

The FSA, RT and CT were calculated quadrantwise and stagewise. The FSA and RT showed a significant negative correlation with disease stage and BCVA (p < .05) in all four quadrants. No significant correlation was noted between CT and BCVA. Multivariate linear regression analysis identified the temporal FSA to correlate best with BCVA.

CONCLUSION

BCVA correlates best with temporal FSA. Smaller the temporal FSA, poorer the vision.

Long-term Clinical Course of Korean Patients Diagnosed with Macular Telangiectasia Type 2

Purpose: To evaluate long-term visual prognosis and changes in the retinal microstructure in patients with macular telangiectasia type 2.Methods: Retrospective analysis of medical records were performed for 61 eyes (32 patients) diagnosed with macular telangiectasia type 2. The visual acuity at diagnosis was compared with that at the final visit. In addition, cases were classified into three grades based on optical coherence tomography (OCT) findings: grade 1, inner retinal cavities only; grade 2, outer retinal cavities with ellipsoid zone disruption; and grade 3, ellipsoid zone disruption with proliferation of retinal pigment epithelium. Change in the grade during the follow-up was verified. In addition, visual acuities were compared between eyes with and without a change in grade.Results: The mean follow-up period was 41.5 ± 33.2 months. Visual acuity had deteriorated significantly from the mean logarithm of the minimal angle of resolution 0.23 ± 0.26 at diagnosis to a mean of 0.31 ± 0.31 at the final visit (p < 0.001). When classified using OCT, 65.6%, 22.9%, and 11.5% were grades 1, 2, and 3, respectively, at diagnosis and 47.5%, 36.1%, and 16.4% at the final visit. Progression of grade was noted in 22.9%. A higher degree of visual deterioration was noted in eyes showing progression than in eyes without (p = 0.002).Conclusions: During the long-term follow-up period, visual deterioration was noted in patients with macular telangiectasia type 2. However, the degree of deterioration was not high. Progression in the disruption of the retinal microstructure was the likely cause of visual deterioration.