Ocular biometric parameters changes and choroidal vascular abnormalities in patients with neurofibromatosis type 1 evaluated by OCT-A.

PURPOSE: To analyze ocular biometric parameters alterations of the posterior pole and choroidal abnormalities in patients with neurofibromatosis type 1 (NF1) by adopting multimodal imaging, especially focusing on the role of novel diagnostic devices like swept-source optical coherence tomography angiography (SS-OCTA). METHODS: In this prospective, case-controlled study, patients with NF1 and age-matched control subjects were quantitatively analyzed by using multimodal imaging. All the subjects underwent confocal scanning laser ophthalmoscopy (SLO), SS-OCT and SS-OCTA examinations. RESULTS: SS-OCT analysis revealed a lower macular retinal nerve fiber layer (RNFL) thickness in patients with NF1 compared with those with suspected NF1 (95.0±15.9 vs 109.7±11.3 µm; P = 0.001) and control subjects (106.8±14.4 µm, P = 0.003). Retinal thickness was significantly lower in NF1 patients compared to those with suspected NF1 (280.7±23.0 vs 304.2±15.3 µm; P < 0.001) and control subjects (298.7±23.8 µm, P = 0.003). The mean vascular flow area of the SCP was significantly higher in patients with NF1 (42.6±2.2%) and suspected NF1 (43.1±2.5%) compared to control subjects (41.0±2.0%; respectively, P = 0.017 and P = 0.002). In the second choroidal layer, the flow area was significantly lower in patients with NF1 compared to control subjects (45.4±4.8 vs 49.0±4.0%,; P = 0.011). CONCLUSIONS: Retinal thicknesses alterations and choroidal nodules are described as ocular manifestations in patients with NF1. In addition, OCTA could represent an important novel advanced imaging technique, capable of detecting early altered retinal and choroidal vascular flow area in patients with NF1.

Biometric and refractive errors evaluation in patients with neurofibromatosis type 1.

PURPOSE: To analyze biometric changes and prevalence of refractive in patients with neurofibromatosis type 1 (NF1). METHODS: Retrospective, case-controlled study involving patients affected by NF1 and healthy control subjects. Data on biometric measurements such as axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), keratometry (K1 and K2) values, and white-to-white (WTW), obtained by use of optical low-coherence reflectometry on a Lenstar LS 900® (Haag-Streit AG, Switzerland) were collected and analyzed. Cycloplegic refractions were then performed. RESULTS: Overall, 166 eyes of 83 patients diagnosed with NF1 (mean age 21.6 ± 9.8) were enrolled and compared with 178 eyes of age-matched healthy subjects (mean age 22.6 ± 6.6). One hundred sixty-six (22.8%) and 33 of 178 (18.5%) eyes were myopic in NF1 patients and healthy subjects, respectively. The prevalence of hyperopia in the NF1 group was 12 of 166 (7.2%) whereas in the healthy control group was 14 of 178 (8.9%). Twenty-nine of 166 (17.4%) and 34 of 178 (19.1%) eyes presented astigmatism in NF1 and control group, respectively. These differences were not statistically significant (p-values > 0.05). Refractive errors such as myopia, hyperopia, and astigmatism were similar between the two groups. The difference of AL, CCT, ACD, LT, K values, and WTW were no statistically significant between the two groups (p-values > 0.05). CONCLUSION: Refractive errors and ocular biometric parameter seem not to be an addition findings of NF1.

Role of visual evoked potentials and optical coherence tomography in the screening for optic pathway gliomas in patients with neurofibromatosis type I.

PURPOSE: The purpose of the present study was to compare visual function assessment, visual evoked potential, and optical coherence tomography with measurement of retinal nerve fiber layer thickness for the diagnosis of optic pathway glioma in children with neurofibromatosis type 1. METHODS: This retrospective observational study included patients with neurofibromatosis type 1 who underwent brain magnetic resonance imaging scan, visual evoked potential study, and peripapillary retinal nerve fiber layer evaluation by optical coherence tomography. Patients were tested with pattern-reversal visual evoked potential and with flash visual evoked potential in case of poor cooperation. Optical coherence tomography was performed with HRA Spectralis (Heidelberg Engineering, Heidelberg, Germany). The area under the curve of receiver operating characteristic curves was used to evaluate the accuracy of each parameter for diagnosing optic pathway glioma. RESULTS: In all, 110 patients with neurofibromatosis type 1 were included in the study. Fifty of them had an optic pathway glioma diagnosed with magnetic resonance imaging, while 60 did not. Global retinal nerve fiber layer thickness demonstrated the highest diagnostic power for discriminating patients with and without optic pathway glioma (area under the curve = 0.758, sensitivity = 65.3%, specificity = 83.3%), followed visual acuity (area under the curve = 0.723, sensitivity = 51.1%, specificity = 91.7%) and P100 of visual evoked potential (area under the curve = 0.712, sensitivity = 69.6%, specificity = 63.8%). CONCLUSION: The results of the present study showed that the measurement of retinal nerve fiber layer thickness was the most efficient test for discriminating patients with and without optic pathway glioma. Brain magnetic resonance imaging remains the gold standard to confirm the diagnosis of optic pathway glioma. Longitudinal studies are required to define if the early detection of tumors with optical coherence tomography could prevent vision loss and morbidity.

Choroidal abnormalities in neurofibromatosis type 1 detected by near-infrared reflectance imaging in paediatric population.

PURPOSE: To investigate choroidal abnormalities in paediatric patients with neurofibromatosis type 1 (NF1) detected by near-infrared reflectance (NIR) retinography in order to evaluate diagnostic accuracy. METHODS: Seventy-eight paediatric patients with NF1, diagnosed according to the National Institutes of Health (NIH) criteria, and 96 healthy control subjects matched for age were examined. Enrolled patients were under 16 years old. The presence of choroidal abnormalities was investigated by confocal scanning laser ophthalmoscopy. Main outcome measure was to evaluate diagnostic accuracy in paediatric patients compared with the NIH criteria. RESULTS: Seventy-eight patients with NF1 (41 female, 37 male; mean age 8.1 ± 3.5 years) were compared with 96 healthy control subjects (42 female, 54 male; mean age 8 ± 3 years). Choroidal abnormalities were observed in 54 (69.2%) of the patients with NF1. As regards the fundus topographical distribution, choroidal abnormalities were more frequent at the posterior pole with a statistically significant correlation between patient age and the number of involved choroidal areas (Spearman r = 0.23; p < 0.04). No choroidal abnormalities were present in the control group. Detection accuracy of choroidal nodules was 70%. CONCLUSION: Choroidal abnormalities appearing as bright patchy regions detected by NIR imaging occurred very frequently in paediatric patients affected by NF1. The present study appears to show that NIR used to detect choroidal involvement allows for elevated diagnostic accuracy.

Plasma homocysteine in patients with retinal vein occlusion.

PURPOSE: To evaluate total plasma homocysteine (HCY) during fasting and post methionine load test (MLT), serum folate, serum vitamin B12, and methylenetetrahydrofolate reductase (MTHFR) mutation in patients with retinal vein occlusion (RVO) and to examine the association between these risk factors and 2 subtypes of RVO: central (CRVO) and branch (BRVO). METHODS: This case-control study included 91 Italian patients presenting a first RVO and 71 healthy subjects, matched by age, without history of thromboembolic diseases, glaucoma, or malignancy. Homocysteine fasting and after MLT, serum folate level, serum vitamin B12 level, and other laboratory tests were assessed. Genetic analysis for the C677T MTHFR mutation was performed. RESULTS: Multivariate logistic regression analysis indicated that hypertension (odds ratio [OR] 2.63; 95% confidence interval [CI] 1.30-5.30; p = 0.007), higher values of fasting HCY (OR 1.16; 95% CI 1.01-1.33; p = 0.03), and low concentrations of vitamin B12 (OR 0.99; 95% CI 0.995-0.999; p = 0.01) were independently correlated with RVO. Moreover, the main determinants for CRVO risk were hypertension (OR 2.46; 95% CI 1.06-5.72; p = 0.04), high values of fasting HCY (OR 1.20; 95% CI 1.02-1.41; p = 0.03), and low concentrations of vitamin B12 (OR 0.99; 95% CI 0.994-0.999; p = 0.008), whereas for BRVO risk only hypertension was significant (OR 2.74; 95% CI 1.24-6.03; p = 0.01). Genotype distribution of the MTHFR C677T mutation did not reveal any significant difference between patients and controls. CONCLUSIONS: These results suggest that elevated fasting HCY levels, low vitamin B12 levels, and hypertension are associated with a risk of RVO, especially for CRVO. Moreover, our data suggest that only hypertension is associated with BRVO risk.

Platelet activation by collagen is increased in retinal vein occlusion.

Retinal vein occlusion (RVO) is the most common retinal vascular disorder second to diabetic retinopathy. The main risk factors in patients with RVO are hypertension, diabetes, hyperlipidemia, increased blood viscosity and glaucoma. The pathogenesis of RVO has not yet been clarified. In these events platelets could play a very important role. In the present study the platelet response to collagen was deeply investigated. Experiments were carried out on a selected group of RVO patients, which were compared to a group of healthy subjects matched for age, sex, clinical and metabolic characteristics. In resting and activated platelets of both groups of subjects p72syk phosphorylation, phospholipase Cgamma2 phosphorylation, protein kinase C activation, intra-cellular calcium levels and nitric oxide formation were measured. Results show that platelets of patients were more responsive to collagen or ADP than healthy subjects and that the response was significantly different (p < 0.0005) at low concentrations of these agonists. In platelets of patients stimulated with collagen increased phosphorylation of p72syk and phospholipase Cgamma2 was found. Also protein kinase C was more activated in patients. In addition intracellular calcium rise induced by collagen was significantly higher in patients than in healthy subjects. RVO patients showed a lower basal level of nitric oxide both in resting and stimulated platelets compared to healthy subjects. Altogether these results suggest that the platelet hyperaggregability described in patients might be an important factor in the development of RVO contributing to the thrombogenic effects.

Oxidative DNA damage in the human trabecular meshwork: clinical correlation in patients with primary open-angle glaucoma.

OBJECTIVE: To evaluate the intensity of oxidative molecular damage and its clinical correlations: visual field damage, intraocular pressure, age, and disease duration. METHODS: DNA was extracted from human trabecular meshwork specimens collected from 17 glaucoma-affected patients using standard filtration surgery. Twenty-one specimens from healthy eyes collected for cornea transplants serve as controls. Oxidative DNA damage was evaluated by determining 8-hydroxy-2'-deoxyguanosine levels. All patients underwent a Humphrey 30-2 visual field examination and diurnal tonometry before surgery. RESULTS: The mean +/- SD DNA oxidative damage was 8.51 +/- 5.44 and 1.75 +/- 1.80 8-hydroxy-2'-deoxyguanosine molecules/10(5) normal nucleotides in patients with glaucoma and controls, respectively. A statistically significant correlation was found among human trabecular meshwork DNA oxidative damage, visual field damage, and intraocular pressure. No other statistically significant correlations were found. CONCLUSIONS: Oxidative stress may represent an important pathogenetic step in primary open-angle glaucoma because it could induce human trabecular meshwork degeneration, favoring an intraocular pressure increase, thus priming the glaucoma pathogenetic cascade.

Systemic linoleic and gamma-linolenic acid therapy in dry eye syndrome with an inflammatory component.

PURPOSE: To evaluate the efficacy and anti-inflammatory activity of systemic linoleic (LA) and gamma-linolenic acid (GLA), which decrease chronic inflammation in rheumatoid arthritis, on the ocular surface of patients with keratoconjunctivitis sicca. METHODS: In a randomized clinical trial, 26 patients with aqueous-deficient keratoconjunctivitis sicca were consecutively selected from patients presenting to Department of Neurosciences, Ophthalmology and Genetics, University of Genoa. The diagnosis was based on dry eye symptom survey score, Schirmer-1 test values, positive vital staining with lissamine green, and fluorescein break-up time (FBUT). All patients had ocular surface inflammation based on HLA-DR expression, a major histocompatibility class II antigen, on epithelial bulbar conjunctiva samples. The subjects were randomly divided into two groups of 13 patients each. The study group received tablets containing LA (28.5 mg) and GLA (15 mg) twice daily for 45 days and used tears; the control group received a tear substitute and a placebo tablet for 45 days. RESULTS: Statistically significant changes in symptoms (p < 0.005), lissamine green staining (p < 0.005), and ocular surface inflammation (p < 0.05) occurred in the study group compared with controls. HLA-DR expression varied from 58.5 +/- 14.1% positive conjunctival cells to 41.3 +/- 18.9% in the treated group and from 61.4 +/- 21.9% to 58.0 +/- 13.3% in the controls. No statistically significant difference between groups was found for FBUT and the Schirmer-1 test. CONCLUSIONS: Therapy with LA and GLA and tear substitutes reduces ocular surface inflammation and improves dry eye symptoms. Long-term studies are needed to confirm the role of this new therapy for keratoconjunctivitis sicca.