COMPUTER ASSISTED RETINAL VESSEL TORTUOSITY EVALUATION IN NOVEL MUTATION FABRY DISEASE: Towards New Prognostic Markers.

PURPOSE: Fabry disease is a rare lysosomal storage disorder with systemic involvement. The authors report on a large Fabry family with GLA p.M187R mutation and exhaustive ophthalmologic assessment. METHODS: Comprehensive systemic evaluation and genetic diagnosis were performed. Ophthalmologic evaluation included intraocular pressure/visual acuity measurement, refractometry, slit lamp examination, retinography, and optical coherence tomography. Three parameters quantified retinal vessel tortuosity: sum of angle metrics, product of angle distance, and triangular index. Calculations were semiautomatized using dedicated software. RESULTS: Ten individuals (2 males and 8 females) were described. Seventy-five percent had retinal vessel tortuosity. One hundred percent had cornea verticillata. Perimacular vessels were predominantly involved. The correlation between the right and left eye tortuosity measurements was very tight. A significant correlation between retinal vessel tortuosity and systemic severity measured by general Mainz Severity Score Index (MSSI), renal MSSI, and neurological MSSI but no cardiac MSSI was observed. Right sum of angle metrics value was an independent statistical predictor of the general-MSSI score in presence of age. CONCLUSION: p.M187R mutation causes a severe systemic and ophthalmologic phenotype, in both male and female patients. Semiautomatic assessment of retinal vessel tortuosity is an objective and reproducible tool. All three parameters of tortuosity are closely associated with Fabry severity scores. Studies of larger series are being awaited to establish the role of retinal vessel tortuosity as a noninvasive marker of disease progression.

Computer-Assisted Evaluation of Retinal Vessel Diameter in Retinitis Pigmentosa.

PURPOSE: The evaluation of retinal vessel attenuation is very subjective and not sufficiently reliable in patients with retinitis pigmentosa (RP). We tested semiautomatic software capable of obtaining real-time measurements of vessel diameter. METHODS: Retinal vessel diameter was calculated in 25 RP subjects and in 20 healthy controls. The Mann-Whitney test was used to compare the average values of RP patients with those of controls and subgroups of RP patients with different clinical features. RESULTS: The retinal vessel diameter was significantly smaller in RP patients than in controls (p < 0.001). In particular, vessel diameters were smaller in older subjects, in patients with worse ERG responses, and in patients with more severe visual field loss. CONCLUSIONS: Computer-assisted analysis of retinal fundus pictures may be helpful in the diagnosis of RP and in monitoring disease progression.

Quantitative Analysis of Conjunctival and Retinal Vessels in Fabry Disease.

Fabry Disease (FD) is a rare X-linked lysosomal storage disorder characterized by systemic and ocular involvement. It has been described an increasing in retinal and conjunctival vessel tortuosity and this feature represents an important marker for the disease. Currently, there is not an objective method to measure and quantify this parameter. We tested a new semi-automatic software measuring retinal and conjunctival vessel tortuosity from eye fundus and conjunctival digital images in a group of FD patients. We performed an observational case-control study evaluating three mathematical parameters describing tortuosity (sum of angle metric [SOAM], product of angle distance [PAD], triangular index [I2e]) obtained from fundus and conjunctival pictures of 11 FD patients and 11 age and sex-matched controls. Both eyes were considered. Mann-Whitney test was used to compare the FD group versus the control group and, within the FD group, male versus female patients. Linear regression analysis was performed to evaluate the possible association of retinal and conjunctival vessels tortuosity parameters with age and with specific markers of systemic disease's progression. The tortuosity parameters (SOAM, PAD and I2e) were significantly higher in retinal vessels and in conjunctival nasal vessels in FD patients in comparison with the controls (p=0.003, p=0.002, p=0.001 respectively for retina) (p=0.023, p=0.014, p=0.001 respectively for nasal conjunctiva). No significant association was found between retinal and conjunctival tortuosity parameters and increasing age or systemic involvement markers. Vessel tortuosity represents an important clinical manifestation in FD. A computer-assisted analysis of retinal and conjunctival vasculature demonstrated an increased vessels tortuosity in patients affected by Fabry disease. This non-invasive technique might be useful to help the diagnosis in early stages, to establish disease severity and monitor its progression.