Filippo Tassi

Fundus autofluorescence imaging in hereditary ATTR amyloidosis with ocular involvement

Abstract Fundus autofluorescence (AF) is a non-invasive technique for the evaluation of intrinsic autofluorescence of the tissues within the eye. In recent years, autofluorescence has become an important diagnostic tool for the assessment of various ocular diseases. A previous study has found that ex vivo Aβ amyloid plaques in the retina of a transgenic mouse model appear hyper-autofluorescent (hyper-AF) under specific wavelengths (excitation at 830 nm, emission at 630). We report the first description of hyper-AF ocular findings in a case of transthyretin-related familial amyloid polyneuropathy (FAP) associated with ocular involvement using AF imaging. A 47-year-old woman from Italy presented to our institution with a history of early onset FAP with ocular involvement due to the rare amyloidogenic transthyretin Glu54Lys mutation. AF imaging showed hyper-AF amyloid deposits associated with retinal vessels in both eyes and a hyper-AF amyloid deposit anterior to the optic disk in the right eye. Conclusion and Relevance: Further studies in FAP patients with different types of genetic mutations and various disease-stages are needed to better establish if non-invasive AF imaging is useful in detecting ocular amyloidosis.

Hemifield pattern electroretinogram in ocular hypertension: comparison with frequency doubling technology and optical coherence tomography to detect early optic neuropathy

Background To assess the sensitivity and specificity of hemifield pattern electroretinogram (HF-PERG) for detecting early retinal ganglion cell (RGC) damage in ocular hypertensive (OH) patients. Methods Fifty-two OH patients (mean age 56±9.6 years) with an intraocular pressure (IOP) .21 mmHg were assessed. All subjects underwent HF-PERG, optical coherence tomography (OCT), and frequency doubling technology (FDT) visual field. Results OH patients showed a significant increase of peak-time of the N95 (P=0.027) compared to controls. The amplitude of the N95 of the lower and upper HF-PERG showed significant differences (P=0.037 and P=0.023, respectively) between the two groups. A significant intraocular (P=0.006) and interocular (P=0.018) asymmetry of N95 amplitude was found. Receiver operating characteristic (ROC) curve analysis revealed a sensitivity of 93% for the N95 of the lower HF-PERG, whereas full-field pattern electroretinogram (PERG) N95 peak-time had a sensitivity of 88%. In OH patients, we found a thinning of OCT - retinal nerve fiber layer (RNFL), especially in the superior and inferior quadrant, although not statistically significant, and a significantly higher FDT pattern standard deviation (FDT-PSD; P=0.001). In the OCT-RNFL inferior quadrant, a sensitivity of 82% was recorded. Finally, the sensitivity of the FDT-PSD was 92%. Conclusion Our study shows that HF-PERG is a very sensitive test for detecting early damage of the RGC.

Convergence, Accommodation, Fusion, and Stereopsis: What Keeps the Eyes Aligned in Intermittent Exotropia?

Purpose To investigate the relationships between angle of deviation, fusional convergence and divergence amplitude, AC/A ratio, near point of convergence (NPC), and myopia-phoria in intermittent exotropia (IXT). Methods 93 patients with IXT, divided into two groups, were recruited in the study. In Group A (73 patients), fusional convergence and divergence amplitudes, NPC, and AC/A ratio were studied and compared with a control group. In Group B (in 20 patients), myopia-phoria while switching from monocular to binocular view was studied with an infrared video retinoscopy and compared with a control group. Results In Group A, positive fusional amplitudes, NPC, and AC/A ratio of IXT patients did not differ from those of normals. Negative fusional amplitudes were significantly higher in the patient group than in the control group. In Group B, myopic shift was statistically significantly higher in the patient group and there was a statistically significant positive correlation between myopic shift and angle of strabismus. Conclusions Apart from the role of fusional convergence which accounts for myopia-phoria, that of the other binocular functions in the control at near of IXT and conversely their specific role in the pathogenesis of IXT remain unclear and the cause of divergent infantile strabismus is still unknown.

Pseudoamblyopia in Congenital Cyclotropia

Purpose To study the effect of surgery on amblyopia and suppression associated with congenital cyclovertical strabismus. Methods The fixation pattern was investigated with microperimetry before and soon after surgery in ten consecutive children operated for congenital superior oblique palsy at the S. Martino Hospital, Belluno, Italy, between September 2014 and December 2015. Changes in visual performance in terms of best-corrected visual acuity (BCVA) and stereopsis between the day before and one week after surgery were also evaluated. No other amblyopia treatment has been administered during the time study. Results Surgical correction of the excyclodeviation in congenital SO palsy determined monocular and binocular sensory consequences: monocularly, in the cyclodeviated amblyopic eye, BCVA (0.46–0.03 LogMAR; p < 0.0001) and the fixation pattern improved, as demonstrated by microperimetry examination. Binocularly, stereopsis improved or emerged while suppression at the Worth four-dot test disappeared. Conclusions In the absence of further amblyopic factors such as coexisting constant vertical and/or horizontal deviation and anisometropia, the amblyopia encountered in congenital SO palsy may resolve soon after the surgical alignment. Therefore, it may be considered and defined “pseudoamblyopia.”

Steady-state pattern electroretinogram and frequency doubling technology in anisometropic amblyopia

Background Steady-state pattern electroretinogram (PERG) and frequency doubling technology (FDT) perimetry can be used to selectively investigate the activity of the M-Y ganglion cells in adult anisometropic amblyopes. Methods Fifteen normal subjects (mean 27.8±4.1 years) and 15 adults with anisometropic amblyopia (mean 28.7±5.9 years) were analyzed using steady-state PERG and FDT. Results The amplitude of steady-state PERG was significantly different not only among the control group and both the amblyopic eye (P=0.0001) and the sound eye group (P=0.0001), but also between the latter two groups (P=0.006). The difference in FDT mean deviation was statistically significant not only between the control group and amblyopic eye group (P=0.0002), but also between the control group and the sound eye group (P=0.0009). The FDT pattern standard deviation was significantly higher in the control group rather than in the amblyopic eye (P=0.0001) or the sound eye group (P=0.0001). A correlation was found between the reduction in PERG amplitude and the increase in FDT-pattern standard deviation index not only in amblyopic (P=0.0025) and sound (P=0.0023) eyes, but also in the healthy control group (P=0.0001). Conclusion These data demonstrate that in anisometropic amblyopia, there is an abnormal functionality of a subgroup of the magnocellular ganglion cells (M-Y), and the involvement of these cells, together with the parvocellular pathway, may play a key role in the clinical expression of the disease.

Alterations Induced by Bangerter Filters on the Visual Field: A Frequency Doubling Technology and Standard Automated Perimetry Study

Purpose. To investigate the effects of Bangerter filters on the visual field in healthy and in amblyopic patients. Materials and Methods. Fifteen normal adults and fifteen anisometropic amblyopia patients were analysed with standard automated perimetry (SAP) and frequency doubling technology (FDT) at baseline and with filters 0.8 and 0.1. Results. With 0.1 filter in SAP there was an increase of MD compared with controls (−10.24 ± 1.09 dB) in either the amblyopic (−11.34 ± 2.06 dB; P < 0.050) or sound eyes (−11.34 ± 1.66 dB; P < 0.030). With filters 0.8 the PSD was increased in the amblyopic eyes (2.09 ± 0.70 dB; P < 0.007) and in the sound eyes (1.92 ± 0.29 dB; P < 0.004) compared with controls. The FDT-PSD values in the control group were increased with the interposition of the filters compared to baseline (0.8; P < 0.0004 and 0.1; P < 0.0010). We did not find significant differences of the baseline PSD between amblyopic eyes (3.80 ± 2.21 dB) and the sound eyes (4.33 ± 1.31 dB) and when comparing the filters 0.8 (4.55 ± 1.50 versus 4.53 ± 1.76 dB) and 0.1 (4.66 ± 1.80 versus 5.10 ± 2.04 dB). Conclusions. The use of Bangerter filters leads to a reduction of the functionality of the magno- and parvocellular pathway.