Choriocapillaris flow deficit in Bietti crystalline dystrophy detected using optical coherence tomography angiography.

BACKGROUND/AIMS: This study aimed to evaluate blood flow in the choriocapillaris in patients with Bietti crystalline dystrophy (BCD) with CYP4V2 mutations using optical coherence tomography angiography (OCTA), and to explore the parameters associated with visual function. METHODS: This prospective case-series study included 13 eyes of 13 consecutive patients with BCD with CYP4V2 mutations and 20 healthy eyes. Using OCTA, we obtained en face images of blood flow in the choriocapillaris. The residual choriocapillaris area on en face images in a 10°×10° macular cube was manually measured and graded according to whether the choriocapillaris remained at the subfovea. We also investigated factors associated with visual acuity (VA) and the mean deviation (MD) value using a Humphrey field analyser with a 10-2 Swedish Interactive Threshold Algorithm standard program among OCTA-derived parameters. RESULTS: Choriocapillaris blood flow deficit was observed in 12 eyes (92%), whereas this was observed in none of healthy eyes. The adjusted residual choriocapillaris area was 2.47±1.79 mm2. The presence of the choriocapillaris at the subfovea was significantly correlated with VA and the MD value (P=0.006, r=0.71; P=0.04, r=-0.59, respectively). CONCLUSIONS: Using OCTA, choriocapillaris blood flow deficit could be observed in most patients with BCD with CYP4V2 mutations. The presence of the choriocapillaris at the subfovea was significantly correlated with visual function in these patients. Analysis of choriocapillaris blood flow using OCTA allows non-invasive assessment of the patient's state.

Multimodal Imaging for Differential Diagnosis of Bietti Crystalline Dystrophy.

PURPOSE: To evaluate the diagnostic usefulness of multimodal imaging in patients with Bietti crystalline dystrophy (BCD). DESIGN: Retrospective cross-sectional study. PARTICIPANTS: Patients with chorioretinal dystrophy accompanied by crystalline-like deposits. The right eyes of the patients were analyzed. METHODS: Fundus photograph, near-infrared reflectance (NIR), fundus autofluorescence (FAF), and OCT images were evaluated. Presence of hyperreflectivity on NIR, well-demarcated areas of decreased FAF, hyperreflective material at or on the retinal pigment epithelium-Bruch's membrane complex, and outer retinal tubulation were graded for each patient. All exons and franking introns of CYP4V2 were screened using Sanger sequencing. MAIN OUTCOME MEASURES: Sensitivity and specificity of the findings to discriminate patients with and without CYP4V2 mutation. RESULTS: In total, 33 patients were included in the study. Sanger sequencing revealed homozygous or compound heterozygous CYP4V2 mutations in 20 patients and heterozygous mutations in 2 patients. Among the investigated factors, hyperreflective appearance on NIR imaging yielded 100% sensitivity and 100% specificity in this cohort. The presence of outer retinal tubulation also was sensitive (95%), but specificity was moderate (45%). The revised diagnoses of patients without CYP4V2 mutations included retinitis pigmentosa, late-onset macular dystrophy, and central areolar choroidal dystrophy. CONCLUSIONS: Multimodal imaging, especially NIR imaging, is useful to differentiate BCD patients with CYP4V2 mutations from patients with other chorioretinal dystrophies accompanied by crystalline-like retinal deposits.

Choroidal Vasculature in Bietti Crystalline Dystrophy With CYP4V2 Mutations and in Retinitis Pigmentosa With EYS Mutations.

Purpose: We compare the choroidal vascular area between Bietti crystalline dystrophy (BCD) patients with CYP4V2 mutations, retinitis pigmentosa (RP) patients with EYS mutations, and normal controls, and investigate the correlation between choroidal vascular area and associated parameters. Methods: This prospective case-series study included consecutive nine eyes of nine BCD patients with CYP4V2 mutations (BCD group), 16 eyes of 16 RP patients with EYS mutations (EYS-RP group), and 16 eyes of 16 normal volunteers matched for age and axial length (control group). Using swept-source optical coherence tomography, we obtained en face images of the choroidal vasculature at the midpoint of the choriocapillaris layer-Sattler's layer (inner choroid) and Haller's layer (outer choroid). After binarization, we compared the inner and outer choroidal vascular areas among the three groups and identified associated factors. Results: The outer choroidal vascular area was 43.34 ± 5.76%, 53.73 ± 4.92%, and 52.80 ± 4.10% in the BCD, EYS-RP, and control groups, respectively. This value was significantly smaller in the BCD group than in the EYS-RP and control groups (P < 0.001 in both; no significant difference between the EYS-RP and control groups). In the BCD group, the outer choroidal vascular area was correlated strongly with the subfoveal inner choroidal thickness (P = 0.001, r = 0.91, respectively). The inner choroidal vasculature could not be identified in eight of nine eyes in the BCD group. Conclusions: The outer choroidal vascular narrowing might progress with the inner choroidal thinning in BCD, and the inner choroidal vasculature might be extinguished in advanced-stage BCD. Our findings may help to clarify the etiology of BCD.

Optical Coherence Tomography Angiography to Estimate Retinal Blood Flow in Eyes with Retinitis Pigmentosa.

Ophthalmologists sometimes face difficulties in identifying the origin of visual acuity (VA) loss in a retinitis pigmentosa (RP) patient, particularly before cataract surgery: cataract or the retinal disease state. Therefore, it is important to identify the significant factors correlating with VA. Nowadays, retinal blood flow in superficial and deep layers can be estimated non-invasively using optical coherence tomography angiography (OCTA). We estimated blood flow per retinal layer by using OCTA; investigated the correlation between VA and other parameters including blood flow and retinal thickness; and identified the most associated factor with VA in patients with RP. OCTA images in 68 of consecutive 110 Japanese RP patients were analysable (analysable RP group). Thirty-two age- and axial length-matched healthy eyes (control group) were studied. In the analysable RP group, the parafoveal flow density in superficial and deep layers was 47.0 ± 4.9% and 52.4 ± 5.5%, respectively, which was significantly lower than that in controls. Using multivariate analysis, we found that the parafoveal flow density in the deep layer and superficial foveal avascular area were the factors associated with VA. Non-invasive estimation of retinal blood flow per retinal layer using OCTA is useful for predicting VA in RP patients.

CHOROIDAL AND RETINAL ATROPHY OF BIETTI CRYSTALLINE DYSTROPHY PATIENTS WITH CYP4V2 MUTATIONS COMPARED TO RETINITIS PIGMENTOSA PATIENTS WITH EYS MUTATIONS.

PURPOSE: To compare atrophy of the choroid and retina between Bietti crystalline dystrophy (BCD) patients and EYS-related retinitis pigmentosa (RP) patients with a similar degree of central visual field defects, age, and axial length (AL). METHODS: Nine eyes of nine BCD patients with CYP4V2 mutations (BCD group) were examined. Moreover, we selected 10 eyes of 10 RP patients with EYS mutations matched for age, axial length, and mean deviation (measured with the 10-2 SITA standard program; EYS-RP group), and 10 eyes of 10 normal volunteers matched for age and axial length (control group). Macular thicknesses of the choroid and retina were measured via swept-source optical coherence tomography. RESULTS: The macular choroid was significantly thinner in the BCD group than in the EYS-RP and control groups, although the thickness did not significantly differ between the EYS-RP and control groups. The macular retina was significantly thinner in the BCD and EYS-RP groups than in the control group, although the thickness did not significantly differ between the BCD and EYS-RP groups at most sites. CONCLUSION: Bietti crystalline dystrophy patients with CYP4V2 mutations showed more severe macular choroid atrophy as compared to EYS-related RP patients. These different damage patterns suggest differences in choroidal expression between CYP4V2 and EYS.

Hyperreflective foci in outer retina predictive of photoreceptor damage and poor vision after vitrectomy for diabetic macular edema.

PURPOSE: To investigate the correlation between visual outcomes and preoperative hyperreflective foci in the outer retinal layers seen on spectral domain optical coherence tomography images in eyes that underwent vitrectomy for diabetic macular edema. METHODS: We retrospectively reviewed 32 consecutive eyes that underwent vitrectomy for diabetic macular edema. Ten eyes had accumulated or many hyperreflective foci in the outer retinal layers preoperatively; 22 eyes did not have the pathology. The logarithm of the minimum angle of resolution and the junction between inner and outer segments were studied in the groups. RESULTS: Logarithm of the minimum angle of resolution was significantly better in eyes without hyperreflective foci than in those with hyperreflective foci at 3 months and 6 months, and the last visit (P = 0.029, 0.010, and <0.001, respectively) compared with no differences at the baseline. Visual improvement was greater in eyes with no hyperreflective foci at the same time points. Seven eyes with hyperreflective foci had no junction between inner and outer segments at the final visit, whereas only 4 eyes with no foci had no junction between inner and outer segments (P = 0.004). However, the foveal thickness did not differ between the groups at any time. CONCLUSION: Preoperative hyperreflective foci in the outer retinal layers detected by spectral domain optical coherence tomography might predict the photoreceptor damage and a poorer prognosis after vitrectomy for diabetic macular edema.