SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY EVIDENCE OF RETINAL NERVE FIBER LAYER AND GANGLION CELL LOSS IN ADULT PATIENTS WITH NEUROFIBROMATOSIS TYPE 1.

PURPOSE: To evaluate peripapillary retinal nerve fiber layer, macular retinal nerve fiber layer, and ganglion cell layer-inner plexiform layer thickness and analyze their correlations in adult patients with neurofibromatosis Type 1 (NF1) and disease-free controls. METHODS: This cross-sectional study was performed at the Azienda Policlinico Umberto I, University of Rome "La Sapienza." All participants underwent complete ophthalmologic examination. Spectral domain optical coherence tomography was used to evaluate peripapillary retinal nerve fiber layer and obtain retinal segmentation measurements to assess macular retinal nerve fiber layer and ganglion cell layer-inner plexiform layer at 1,000 µm nasal, temporal, superior, and inferior to the fovea. RESULTS: Thirty-four eyes of 17 patients with NF1 (mean age, 42.2 ± 14.3 years) and 34 eyes of 17 disease-free control subjects (mean age, 41.4 ± 12.2 years) were included. All participants had best-corrected visual acuity of 20/20. The mean thickness of peripapillary retinal nerve fiber layer, macular retinal nerve fiber layer, and ganglion cell layer-inner plexiform layer was lower in patients with NF1 with respect to controls (P = 0.003, P = 0.022, P < 0.001, respectively). Regression analysis showed a significant correlation (P < 0.001) between mean ganglion cell layer-inner plexiform layer thickness and mean peripapillary retinal nerve fiber layer thickness in patients with NF1. CONCLUSION: Retinal nerve fiber layer and ganglion cell loss correlate well with each other in adult patients with NF1 in comparison with a healthy control population.

Ophthalmic Alterations in the Sturge-Weber Syndrome, Klippel-Trenaunay Syndrome, and the Phakomatosis Pigmentovascularis: An Independent Group of Conditions?

The phakomatoses have been traditionally defined as a group of hereditary diseases with variable expressivity characterized by multisystem tumors with possible malignant transformation. The Sturge-Weber syndrome, Klippel-Trenaunay syndrome, and the phakomatosis pigmentovascularis have the facial port-wine stain in common. Numerous pathophysiogenetic mechanisms have been suggested such as venous dysplasia of the emissary veins in the intracranial circulation, neural crest alterations leading to alterations of autonomic perivascular nerves, mutation of the GNAO gene in the Sturge-Weber syndrome, PIK3CA mutation in malformative/overgrowth syndromes such as the Klippel-Trenaunay syndrome, and the twin-spotting phenomenon in phakomatosis pigmentovascularis. Other features linked to the port-wine stain and typical to all of the three conditions are glaucoma and choroidal alterations. Glaucoma can be due to malformations of the anterior chamber or high episcleral venous pressure and in phakomatosis pigmentovascularis it can also be associated with angle hyperpigmentation. The choroid can be thickened in all diseases. Furthermore, choroidal melanocytosis in the phakomatosis pigmentovascularis can lead to malignant transformation. Although the multiple pathophysiological mechanisms still require clarification, similarities in ophthalmic manifestations make it reasonable to classify these diseases in an independent group.

Morphologic and vasculature features of the choroid and associated choroid-retinal thickness alterations in neurofibromatosis type 1.

BACKGROUND/AIMS: A normal structural and functional choroid is essential in supplying blood flow to the retina. Neurofibromatosis type 1 (NF1) is a neurocristopathy where the choroid is altered due to the presence of nodules. The present transversal study was conducted to examine choroidal nodules and their effect on choroidal and retinal thickness in NF1 patients. METHODS: Near-infrared reflectance and optical coherence tomography with enhanced depth imaging were used to evaluate choroidal morphology and vasculature in 19 patients with NF1 and 19 healthy, age-matched control subjects. Choroidal thickness, neuroepithelium thickness, photoreceptors together with retinal pigment epithelium (RPE) thickness and outer nuclear layer (ONL) thickness were measured at the fovea and 1000 µm nasal, temporal, superior and inferior to the fovea in NF1 patients and control subjects. Choroidal and neuroepithelium thickness were assessed overlying and adjacent to nodules in NF1 patients. RESULTS: Choroidal nodules were classified as 'dome-shaped' or 'placcoid' subtypes in 17 patients. Small and medium calibre choroidal vessels were observed above dome-shaped nodules where choroidal thickness was significantly reduced. There was a statistically significant reduction in mean choroidal thickness (p=0.013) in NF1 patients with respect to control subjects. The neuroepithelium, photoreceptors together with RPE and ONL had a statistically significant reduction in mean thickness in NF1 patients (p<0.001, p<0.001, p=0.012, respectively). CONCLUSIONS: In NF1, there are dome-shaped and placcoid choroidal nodules which alter choroidal morphology and thickness. There is reduction in mean choroid thickness with generalised thinning of the neuroepithelium, photoreceptors together with RPE and ONL in NF1 patients.

Retinal microvascular abnormalities overlying choroidal nodules in neurofibromatosis type 1.

BACKGROUND: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder involving aberrant proliferation of multiple tissues of neural crest origin. Retinal vascular alterations in NF1 have rarely been reported in the literature and their nature is not clear. This study describes distinctive retinal microvascular alterations and their relationship to choroidal nodules in patients with neurofibromatosis type 1. METHODS: This was a retrospective study where records of seventeen consecutive patients with diagnosis of NF1, presenting Lisch nodules and choroidal alterations, and 17 age and gender-matched healthy control patients were evaluated. Fundus photographs, near infrared reflectance and enhanced depth imaging - optical coherence tomography images were reviewed. Retinal microvascular abnormalities and choroidal and retinal alterations in proximity of the retinal microvacular alterations were carefully noted. RESULTS: 6 patients (35%) presented distinctive microvascular abnormalities. These consisted of small, tortuous vessels with a "spiral" or "corckscrew" aspect. They were second or third order, small tributaries of the superior or inferior temporal vein. These vessels were all located overlying choroidal alterations as observed with near infrared reflectance. Enhanced depth imaging - optical coherence tomography showed alteration of choroidal vasculature due to the presence of choroidal nodules but otherwise retinal and choroidal cross-sections were unremarkable for morphology. CONCLUSIONS: Retinal microvascular alterations overlying choroidal nodules in patients with NF1 can be considered another distinctive characteristic of the disease. Although the nature of these alterations is not clear, the authors speculate that functional disorders of vasomotor nerve cells, which originate in the embryonal neural crest can lead to their formation.