Evaluation of the Foveal Avascular Zone in Familial Exudative Vitreoretinopathy Using Optical Coherence Tomography Angiography.

PURPOSE: To evaluate the foveal avascular zone (FAZ) and retinal structure in familial exudative vitreoretinopathy (FEVR). PATIENTS AND METHODS: Eighteen eyes with stage 1 or 2 FEVR and 20 control eyes were evaluated. The central retinal thickness (CRT), foveal inner retinal thickness (IRT), surface retinal vessel density (SRVD), and deep retinal vessel density (DRVD) were measured using optical coherence tomography. The FAZ area was calculated using ImageJ software. The equivalent spherical value (SE) and axial length (AL) were measured. RESULTS: The CRT (232.5±3.086 vs 211±12.6325 µm; p=0.003) and foveal IRT (15.83±13.95 vs 0.9±4.02 µm; p=0.002) were thicker in the FEVR group than in the control group. The surface FAZ area (0.265±0.08 vs 0.364±0.09 mm2; p=0.004) and the deep FAZ area (0.364±0.1 vs 0.484±0.11 mm2; p=0.03) were smaller in the FEVR group than in the control group. The SRVD values did not differ among the sectors, but the DRVD was higher in the FEVR group except for the inferior sector (superior, p=0.027; inferior, p=0.88; temporal, p=0.035; nasal, p=0.027). The SE and AL did not differ between the two groups. There were no correlations between the surface and deep layer FAZ area and age, CRT, SE, and AL. The surface, deep FAZ area, and foveal IRT were correlated negatively (surface, r = -0.47, p=0.033; deep layer FAZ area, r = -0.46, p=0.037). CONCLUSION: Eyes with FEVR have a smaller FAZ because the vascular structure in the inner retina remained in the fovea.

Optical coherence tomography findings in unilateral peripheral cone dysfunction syndrome: a case report.

INTRODUCTION: To report a case of unilateral peripheral cone dysfunction syndrome and evaluate the associated clinicopathological changes using swept-source optical coherence tomography (SS-OCT). CASE PRESENTATION: A 39-year-old Japanese woman reported a visual field defect of 2-years duration in the right eye. The patient underwent visual field testing, full-field electroretinography (ff-ERG), SS-OCT, and a routine ophthalmologic examination. The best-corrected visual acuity was 20/20 bilaterally. The funduscopy examination was normal bilaterally. Visual field testing showed a relative paracentral scotoma in the right eye. SS-OCT scans showed an unclear interdigitation zone (IZ) throughout the posterior pole except for the foveal zone in the right eye. SS-OCT macular analysis showed thinning of the ganglion cell layer (GCL) and inner plexiform layer (IPL) corresponding to the region of the IZ defect. ff-ERG showed almost normal flash ERGs and normal rod responses bilaterally. The cone response and flicker ERG response were decreased markedly only in the right eye. CONCLUSION: To the best of our knowledge, this is the first case report of unilateral peripheral cone dysfunction syndrome in which SS-OCT showed pathological changes in the GCL and IPL. The OCT findings corresponded well to the ERG changes and visual field abnormality. Because foveolar cone photoreceptor cells are connected in a one-to-one correspondence to retinal ganglion cells without connection to the horizontal cells or amacrine cells, the GCL and IPL were not present in the fovea. Based on this analysis, we speculated that the primary lesion of peripheral cone dysfunction syndrome is not in the cone photoreceptor cells but in the horizontal cells and/or amacrine cells. The clinicopathological changes in the ganglion cells and cone photoreceptor cells might be the subsequent pathologies in the horizontal cells in peripheral cone dysfunction syndrome.

Effects of mydriasis and miosis on kinetic perimetry findings in normal participants.

PURPOSE: To evaluate the effects of pharmacologically induced mydriasis and miosis on kinetic perimetry findings in normal participants. METHODS: Thirty-eight eyes of 38 healthy young participants underwent kinetic perimetry (Octopus 900 perimeter) with III4e, I4e, I3e, I2e, and I1e stimuli. For each participant, 24 predetermined meridians with 15° intervals were automatically tested with a velocity of 3°/s under normal, mydriatic, and miotic conditions. Mydriasis and miosis were induced by one drop of 0.4 % tropicamide and 2 % pilocarpine hydrochloride, respectively. The isopter area and kinetic sensitivity were compared between the three pupil conditions. RESULTS: The average pupil size in the normal condition was 5.6 ± 0.9 mm, and it significantly increased to 8.5 ± 0.7 mm after mydriasis (p < 0.01) and decreased to 3.4 ± 0.8 mm after miosis (p < 0.01). Compared to the normal pupil, the isopter area of the dilated pupil was not significantly different under the III4e stimulus; however, it significantly decreased under the I4e, I3e, I2e, and I1e stimuli (p < 0.01). Compared to the normal pupil, the isopter area of the constricted pupil significantly decreased (p < 0.01) with the III4e stimulus and significantly increased with the I3e and I2e stimuli (p < 0.05). CONCLUSIONS: For both pupil conditions, kinetic sensitivity at each meridian showed a similar trend to the isopter area under each stimulus. The isopter area of the dilated pupil generally decreased, whereas the isopter area of the constricted pupil showed various findings. Therefore, careful attention should be paid to changes in the isopter area associated with changes in the pupil size.