[Primary open angle glaucoma and sleep apnea syndrome: A review of the literature]. / Glaucome primitif à angle ouvert et syndrome d'apnée du sommeil : une revue de la littérature.

The relationship between glaucoma and Obstructive Sleep Apnea Syndrome (OSAS) has long been discussed, with conflicting study findings. OSAS appears in the most recent studies to be more of an aggravating factor than an independent risk factor for glaucoma. Patients with OSAS may develop a more rapid progression of primary open-angle glaucoma (POAG). OSAS may damage the optic nerve not only by increasing the intraocular pressure (IOP) but also by altering the blood supply to the optic nerve as shown by more recent work with OCT-Angiography. Although the systemic benefits of Continuous Positive Airway Pressure (CPAP) have been demonstrated, few studies have evaluated its effect on the optic nerve. CPAP might act on glaucomatous neuropathy by improving the blood supply to the optic nerve. The study of this mechanism of action might provide new insights into the relationship between OSAS and glaucoma.

Comparison of retinochoroidal and optic nerve head microvascular circulation between HIV-positive patients and healthy subjects using optical coherence tomography angiography.

PURPOSE: To evaluate the retinal, choroidal, and optic disc head microvascular circulation in human immunodeficiency virus (HIV)-infected individuals without retinopathy receiving highly active antiretroviral therapy (HAART) using swept-source optical coherence tomography angiography (SS-OCTA). METHODS: This cross-sectional study included 100 eyes of 100 patients with HIV infection but no HIV-related ocular disease and 108 eyes of 108 age- and sex-matched healthy subjects as the control group. SS-OCTA was used to assess foveal avascular zone (FAZ) area, retinal nerve fiber layer thickness (RNFL), choriocapillaris (CC) flow area, outer retinal (OR) thickness, radial peripapillary capillary (RPC) vessel density (VD), ONH VD, and choroidal thickness. RESULTS: No statistically significant difference was found between the two groups except in the foveal VD of the deep capillary plexus (DCP). The foveal VD of the DCP was lower in the HIV-positive group (P=0.011). The mean FAZ area (mm2), perimeter (mm), and CC flow area (mm) values were higher in the HIV-positive group at statistically significant levels (P=0.021, P=0.02, and P=0.039, respectively). However, no statistically significant differences were found between the two groups concerning the OR flow area, subfoveal choroidal thickness, or the VDs of the RPC or ONH. CONCLUSIONS: This is the first study in the literature to evaluate the microvascular circulation of the ONH in HIV-positive patients. Although retinal and choroidal microvascular circulation decreased in HIV-positive patients receiving HAART treatment, we found no effect on the microvascular circulation of the ONH or RPC microvascular circulation. Our findings suggest that retinochoroidal microvascular circulation is affected in HIV-positive patients over time.

[Biomechanics of the lamina cribrosa: A determining factor in glaucomatous neuropathy. A review of the literature]. / Biomécanique de la lame criblée : un facteur déterminant de la neuropathie glaucomateuse. Une revue de la littérature.

Glaucoma is a chronic optic neuropathy characterized by progressive sclero-laminar remodeling. The main factor at the origin of these deformations is the intraocular pressure (IOP), the effect of which varies according to the biomechanical properties of the individual lamina cribrosa (LC). In this environment, the LC represents a malleable zone of weakness within a rigid corneoscleral shell. It is a dynamic structure whose movements play a key role in the pathogenesis of glaucoma: displacing it posteriorly, in addition to contributing to the characteristic appearance of glaucomatous cupping, would increase constriction on the nerve fibers and the laminar capillaries. Often incorrectly considered permanent in adults, these deformations have a certain degree of reversibility, which is currently better characterized thanks to progress in imaging techniques. The occurrence of anterior displacement and laminar thickening following a reduction in IOP could thus constitute a good prognostic factor by reducing mechanical stress on this region. These changes would tend to reduce laminar pore tortuosity and shear forces, which are probably key mechanisms of axonal loss in glaucoma.

Optic nerve sheath fenestration: Current status in France and comparison of 6 different surgical approaches.

PURPOSE: Optic nerve sheath fenestration (ONSF) is a surgical procedure commonly performed in the Anglo-Saxon countries for the treatment of medically refractory idiopathic intracranial hypertension (IIH). We chose to compare 6 different trans-orbital surgical approaches to ONSF. We also desired to determine the number of optic nerve decompression procedures performed in France in 2019 and 2020. METHODS: Four fresh frozen orbits were dissected at the University of Nice anatomy laboratory. We performed the following surgical approaches: (i) eyelid crease, (ii) lid-split, (iii) medial transconjunctival with medial rectus disinsertion, (iv) medial transconjunctival without rectus disinsertion, (v) lateral transconjunctival and (vi) lateral orbitotomy. For each surgical approach, we measured the distance between the incision and the optic nerve dura mater. We also extracted data from the French National PMSI (Programme de Médicalisation des Systèmes d' Information) database from January 2019 through December 2020 to determine the annual number of optic nerve decompression procedures. RESULTS: The lid crease and medial transconjunctival approaches provided the shortest distance to the optic nerve (average 21mm and 24mm, respectively) and the lowest levels of difficulty compared to the other surgical routes. A total of 23 and 45 optic nerve decompressions were performed in France in 2019 and 2020, respectively. Among them, only 2 and 7 procedures, respectively, were performed through a trans-orbital approach. CONCLUSION: Upper lid crease incision and medial transconjunctival approaches are the most direct and easiest surgical routes when performing an ONSF. We found that ONSF was rarely performed in France. We strongly recommend close cooperation between ophthalmologists, neurologists, neurosurgeons and interventional radiologists.

[Leber hereditary optic neuropathy: clinical picture and initial workup data]. / Neuropathie optique héréditaire de Leber : tableau clinique et données du bilan initial.

Leber hereditary optic neuropathy (LHON) is a rare mitochondrial disease, responsible for blindness by bilateral involvement of central vision. It usually affects young men but can occur at any age and in women. Its diagnosis is suspected on the family history and the initial clinical picture, and the definitive diagnosis of LHON is obtained by genetic testing and the molecular identification of the mitochondrial genetic point mutation. The initial workup should include an assessment of visual structure and function. Its visual prognosis is severe, but depends on the causative mutation. Support should include genetic counseling, a therapeutic proposal and a support for visual impairment.

[Role of the lamina cribrosa in the pathogenesis of glaucoma. A review of the literature]. / Rôle de la lame criblée dans la pathogenèse du glaucome. Une revue de la littérature.

Located within the scleral canal, the lamina cribrosa is a sieve-like structure separating the intraocular and retrobulbar portions of the optic nerve. Identified as the main site of axonal damage in glaucomatous optic neuropathy, the study of the lamina cribrosa has been of great interest for many years. Numerous studies have explored the histological and morphological characteristics of the laminar region in healthy subjects as well as glaucoma patients. More recently, the development of adaptive optics systems and new generations of OCT has allowed great progress in the understanding of the pathogenesis of glaucoma and has opened new perspectives for the improvement of diagnostic procedures.

Optic nerve motion and gaze direction: Their impact on intraorbital tumor radiotherapy.

PURPOSE: Management of inter- and intra-fraction movements of target volumes and organs at risk (OARs) during radiotherapy is essential. While there is little OAR or target volume movement, the movements and orientation of the eyes can be significant during radiotherapy and they can affect the position of the optic nerve. The objective of the present study was to assess the variations of the optic nerve position due to gaze direction and to discuss their clinical consequences on the radiation treatment of intraorbital tumors. MATERIAL AND METHODS: Three patients without a history of oculomotor nerve palsy underwent six CT acquisitions with a thermoplastic mask: eyes open with different gaze directions (straight ahead, left, right, up, down) and eyes closed. The acquisition with the straight-ahead gaze was chosen as the reference position. Left and right optic nerves were segmented on the six acquisitions, and total volumes and maximum amplitude motions were calculated in three dimensions. RESULTS: Maximum differences were observed while looking left and up, with a median maximum amplitude of 5 and 6mm [range: 2-7mm], respectively. These motions induced a position variation of more than 50% of the volume of the optic nerve (compared to the reference position). Greater variations of motion were observed for the anterior portion of the nerve. The gaze position with the fewest variations compared to the reference position was eyes closed. CONCLUSION: Optic nerve positions vary significantly due to the gaze direction, especially for the anterior portion of the nerve. These variations should be taken into account for the treatment of small intraorbital tumors involving the anterior third of the optic nerve.

Papilledema secondary to vestibular schwannoma: An atypical case without intracranial hypertension.

In most cases, vestibular schwannomas with papilledema are associated with intracranial hypertension secondary to hydrocephalus (obstructive or communicating). We describe the atypical case of a 39-years-old man who presented with bilateral papilledema revealing a vestibular schwannoma, but without hydrocephalus and with normal intracranial pressure. Ophtalmologic signs were completely resolved after tumor removal. The pathophysiological mechanism generally described to explain bilateral papilledema in such cases is tumor-induced hyperproteinorachia. However, in the absence of hydrocephalus or intracranial hypertension, this case raises the question of the mechanisms involved in the visual impairment related to vestibular schwannoma.

Electrophysiological reactions to intraoperative irritation of the optic nerve. Case report and review of possible mechanisms.

BACKGROUND: Intraoperative control of optic nerve function conservation during neurosurgical operations currently relies mainly on visual evoked potential monitoring. Unfortunately, this detects peril only when the visual pathways are already compromised, sometimes irreversibly. In contrast, electrophysiological stimulation mapping of the nerves can be a fully preventive measure. However, direct sensory nerve mapping requires the patient to be awake during surgery, which is unfeasible for surgeries targeting the optic nerve area. Another possible approach to sensory nerve mapping involves unconditioned electrophysiological responses evoked by sensory nerve stimulation. The key point for this approach is the possibility of obtaining such responses for a particular sensory nerve under surgical anesthesia. CASE REPORT: A 52-year-old woman presented with meningioma in the area of right optic nerve and chiasm. She underwent microsurgical removal of the tumor through the transciliary supraorbital approach. During surgery, electrodes at the inferior margin of the right orbit repeatedly recorded electrophysiological reactions following contacts and displacements of the right optic nerve by the surgical instruments. CONCLUSIONS: The observed reactions suggest that either the unconditioned blink reflex or antidromic electroretinographic response to optic nerve irritation was conserved under total intravenous anesthesia. This observation might be of value for development of intraoperative optic nerve mapping. This in turn could increase patient safety by identifying the exact optic nerve location before any negative impact on it.

Evaluations of the radial peripapillary, macular and choriocapillaris microvasculature using optical coherence tomography angiography in patients with systemic sclerosis.

PURPOSE: To analyze the macular microvascular (MMV) architecture, radial peripapillary capillary (RPC) network and choriocapillaris using optical coherence tomography angiography (OCT-A) in patients with systemic sclerosis (SSc) without systemic comorbidities. METHODS: The vessel densities (VDs) of the MMV, foveal avascular zone (FAZ) parameters, choriocapillaris flow areas (CCFAs), RPC VDs, and optic nerve head (ONH) parameters were measured by OCT-A. Retinal thickness and subfoveal choroidal thickness (SFCT) were measured by spectral-domain optical coherence tomography (SD-OCT). The SD-OCT and OCT-A measurements of 53 eyes of 30 SSc patients were compared with 61 eyes of 33 healthy controls. RESULTS: In the MMV analysis, a decrease in the VDs of the superficial capillary plexus and an increase in the FAZ area, FAZ perimeter and non-flow area were detected in the SSc group compared to the controls (P=0.007, P=0.001, P=0.029, P=0.018, and P=0.039, respectively). While there was a decrease in SFCT, no change was found in CCFA (P=0.001 and P=0.902, respectively). The RPC analysis revealed a decrease in the VDs of all vessels for the entire area and the intradisc area, as well as the VDs of the small vessels for the intradisc area (P=0.021, P=0.001, and P=0.003, respectively). In the ONH analysis, there was an increase in the C/D area ratios and cup volumes, and a decrease in the rim areas and nasal quadrant retinal nerve fiber layer thickness (P=0.004, P=0.004, P=0.013, and P=0.032, respectively). CONCLUSION: Decreases in RPC and MMV VDs and changes in ONH parameters were found in OCT-A measurements in patients with SSc.

Optic disc microvascularity in patients with intravitreal dexamethasone implantation for branch retinal vein occlusion.

PURPOSE: To compare changes in optic disc microvascular parameters before and after treatment of patients who received IVD for macular edema secondary to BRVO, using optical coherence tomography angiography (OCT-A). METHODS: Eighteen BRVO patients who received only IVD treatment and 20 healthy controls were retrospectively reviewed. Patients with moderate or severe IOP spikes (>6mmHg) after implantation were excluded from the study. Whole, peripapillary, inside disc capillary density and retinal nerve fiber layer thickness (RNFLT) were recorded at the 2nd and 6th months after implantation. RESULTS: Whole, peripapillary and inside disc capillary densities were significantly lower in BRVO patients before implantation than in the control group (P<0.001 for all comparisons). Despite a mild mean IOP increase after IVD, no significant change was observed in whole, peripapillary and inside disc capillary vascular densities in the 2nd and 6th months (P>0.05 for all comparisons). The mean RNFLT of BRVO patients before IVD was lower than the control group, but this difference was not statistically significant (110.1±12.3µm and 115.6±10.7µm, P=0.131). The mean RNFLT at the 2nd and 6th months did not show a statistically significant difference after implantation (P=0.239, P=0.459). CONCLUSIONS: OCT-A shows the decrease in whole, peripapillary and inside disc microvascular parameters in BRVO patients compared to healthy subjects. No significant change in optic nerve head microvascular parameters was observed in patients without moderate or severe IOP spikes after treatment with IVD.

Pattern of oculomotor and visual function in children with hydrocephalus.

PURPOSE: To investigate the ocular motility disturbances, optic nerve changes, and refractive errors in children with or without surgically treated hydrocephalus. METHODS: This retrospective study included 63 subjects diagnosed with hydrocephalus between 2007 and 2019 at the Baskent University Hospital. Full orthoptic and ophthalmic examination and brain magnetic resonance imaging were performed in all subjects. RESULTS: The mean age of patients was 68.4±27.6 months, and the mean follow-up time was 21.3±5.2 months. Twenty-one (51.2%) patients had esotropia (ET), and 14 (34.1%) had exotropia (XT). Of the patients with ET, 9 (14.2%) had a sixth nerve palsy. Four patients (6.3%) had a fourth nerve palsy, and 1 had a superior rectus palsy. Eleven patients had manifest, and 2 latent, nystagmus. Thirteen (20.6%) patients had optic disc abnormalities. The mean BCVA was 0.4±0.2 (0.05-1.0) in the right eye and 0.5±0.2 (0.1-1.0) in the left eye. Of the 19 (30.1%) patients who had a significant refractive error, 9 (47.3%) had hyperopia. Thirty-six (57.1%) patients had ventriculoperitoneal shunt surgery, and 11 (30.5%) of them had shunt revision due to occlusion. Ocular motility disorders were found to be significantly more common in patients who underwent single shunt surgery and shunt revision than those who had no surgical procedure (P=0.041and P=0.032, respectively). CONCLUSION: The evaluation of ocular motility disorders and visual dysfunction in hydrocephalic children can be a source of valuable information when diagnosing and following the disease.

Visual field defects due to optic nerve drusen in Afro-Caribbean patients: A case series of 16 eyes.

INTRODUCTION: Optic Nerve Head Drusen (ONHD) are very rare among black patients but may cause more severe visual defects in these patients. The goal of our study was to describe the frequency of visual field defects secondary to OND in Afro-Caribbean patients and study the characteristics of their physical examination, color vision and contrast sensitivity. METHODS: We carried out a prospective study at the Martinique university medical center on patients of African descent with ONHD diagnosed on fundus examination and B-scan ultrasonography. All patients received a complete neuro-ophthalmological examination. The primary study endpoint was the frequency of visual field defects. Secondary study endpoints were the results of ETDRS visual acuity, Pelli-Robson contrast sensitivity chart, and 15 hue color vision test. RESULTS: Sixteen eyes of 10 patients from 11 to 68 years of age were included. Forteen eyes (87%) had exposed ONHD. Eleven eyes (69%) showed a visual field defect: 9 eyes (69%) had an enlarged blind spot, and 9 eyes (69%) had an arcuate scotoma. 3 eyes (19%) had loss of ETDRS visual acuity, and 12 eyes (75%) showed loss of Pelli-Robson contrast sensitivity. Five eyes (31%) had an abnormal color vision test. CONCLUSION: This is one of the largest case series of ONHD in Black patients. The frequency of visual field defects was high but comparable to that of studies in other ethnic groups. Larger comparative studies are necessary to confirm these results.

[Impact of prematurity on the optic nerve]. / Impact de la prématurité sur l'aspect morphologique et tomographique du nerf optique.

INTRODUCTION: Thanks to the progress made in the past few years in pediatric intensive care as well as the increased survival of preterm infants, the consequences of premature birth are increasingly well documented. With regard to ophthalmologic complications, retinopathy of prematurity is well described, but the optic nerve may also be affected. The goal of this study is to compare the optic nerves of preterm infants as a function of their gestational period with a control group of the same age. MATERIALS AND METHODS: We conducted a case-control study pairing a full-term infant with each preterm infant. Inclusion criteria were: any child from 5- to 10-years-old, separated into three sub-groups according to their degree of prematurity. Variables were: cup/disc ratio, ocular biometry, intraocular pressure and RNFL thickness. RESULTS: Thirty-seven preterm infants and 37 controls were included in the study. The mean age at the time of inclusion was 7.05 years for the preterm group and 7.19 years for the control group. No significant difference was observed in axial length or spherical equivalent (P=0.31 and P=0.98, respectively). No significant difference was observed in pachymetry or intraocular pressure (P=0.28 and P=0.22, respectively). We observed a significant increase of 0.1 in the cup/disc ratio of the preterm group compared to the control group (P<0.05). The preterm group cup/disc ratio was 0.36 versus 0.27 for the control group. No significant difference was observed in the 7 quadrants of RNFL between the two groups. However, when comparing infants born before 28 weeks gestation with the control group, we observed a mean decrease of 14.5 microns in the superior temporal sector (P=0.04), a 9 micron decrease in the global thickness G (P=0.03) and a 12.7 micron decrease in the nasal sector (P=0.01). CONCLUSIONS: In the case of the studied children (aged 5 to 10), the reduced RNFL fiber thickness is a phenomenon dependent essentially on the stage of prematurity. It would be useful to follow these preterm populations over the long term and to compare them to a matched control group to be able to obtain functional results.

Multimodal imaging in optic nerve melanocytoma: Optical coherence tomography angiography and other findings.

PURPOSE: To evaluate optical coherence tomography (OCT), fundus autofluorescence (FAF) imaging and optical coherence tomography angiography (OCTA) as diagnostic tools in optic disc melanocytoma (ODM) and study the differences in peripapillary and macular vascular density in eyes with ODM using OCTA. METHODS: Patients with ODM were enrolled in this case series. Each patient underwent evaluation of best-corrected visual acuity, slit-lamp biomicroscopy, fundus examination, fundus photography, standard visual field testing, spectral domain OCT, ultrasound B-scan examination, FAF, fluorescein angiography and OCTA. RESULTS: Eight patients (three males and five females) with ODM (9 eyes) were enrolled. The largest ODM presented a nodular appearance with a hyper-reflective tumor surface and a posterior optical shadow on OCT. FAF images showed hypoautofluorescence of the tumor with well-defined outlines. Analysis of optic nerve vascular area showed decreased values in the radial peripapillary capillary plexus (3 of 5) and the outer retinal plexus (4 of 5) in the eyes with ODM. In contrast, the ODM eyes had a higher macular vascular area in the deep capillary plexus in 4 of 6 patients. CONCLUSIONS: ODM may be associated with changes in peripapillary and macular perfusion, with an increase in peripapillary vascularization being a possible risk factor for growth. OCTA might be a helpful objective method in the analysis of changes in flow in patients with ODM.

Agreement between Fourier-domain and swept-source optical coherence tomography used for optic nerve head measurements.

PURPOSE: To assess the correlation between optic nerve head measurements generated by Fourier-domain (FD) and swept-source (SS) optical coherence tomography (OCT) both in healthy Caucasian subjects and patients with primary open angle glaucoma (POAG). MATERIALS AND METHODS: This was a cross-sectional study of the right eyes of 118 subjects. In each participant, the measurements of disc area, cup to disc ratio (CDR), vertical cup to disc ratio (VCDR), rim area and rim volume were performed consecutively by FD-OCT and then SS-OCT. Participant age, gender and spherical equivalent were also recorded. Agreement between the two devices was assessed through intraclass correlation coefficients (ICC) and Bland-Altman plots. RESULTS: The study sample consisted of 95 healthy eyes and 23 eyes with glaucoma. Mean participant age was 48.6±20.0 years, 54.2% were female, and mean spherical equivalent was -1.6±3.0 diopters. FD-OCT and SS-OCT measurements were respectively: mean disc area 1.79±0.3 vs 1.83±0.3 mm2 (ICC=0.71), mean CDR 0.38±0.2 vs 0.33±0.2 (ICC=0.91), mean VCDR 0.58±0.2 vs 0.52±0.2 (ICC=0.92), mean rim area 1.05±0.4mm2 vs 1.03±0.5mm2 (ICC=0.29), and mean rim volume 0.14±0.11 vs 0.21±0.17mm3 (ICC=0.53). Good agreement between the devices was noted for rim area and rim volume in glaucoma subjects (ICC=0.76 and 0.68 respectively), while weak agreement was observed for these variables in healthy subjects (ICC≤0.50). CONCLUSIONS: The CDR and VCDR measurements provided by FD and SS OCT showed excellent agreement for the overall sample. When the devices were used for rim measurements, agreement was excellent only in the POAG patients.

[Congenital abnormalities of the optic disc]. / Anomalies congénitales de la papille.

Congenital abnormalities of the optic disc are not uncommon in clinical practice and should be recognized. Size abnormalities of the optic disc include optic disc aplasia, hypoplasia, megalopapilla, and optic disc cupping in prematurity. Among congenital excavations of the optic disc head, morning glory disc anomaly and optic disc pit can be complicated by serous retinal detachment; the papillorenal disc is an association of bilateral optic disc cupping and renal hypoplasia which should be ruled out; optic disc coloboma is caused by an abnormal closure of the embryonic fissure and can be complicated by choroidal neovascularization and retinal detachment. Other abnormalities that will be discussed are congenital tilted disc syndrome, duplicity of the optic disc head, congenital pigmentation of the optic disc head and myelinated retinal nerve fibers. All of these abnormalities can be associated with syndromes and neurological diseases, as well as other potentially blinding ophthalmological defects which can be secondarily complicated by amblyopia, strabismus and nystagmus. Thus, they should be recognized in order to plan for appropriate follow-up.

A study of optic nerve head drusen in 38 pseudoxanthoma elasticum (PXE) patients (64 eyes). Location of optic nerve head drusen in PXE.

PURPOSE: To investigate the prevalence and location of optic nerve head drusen and their potential association with other PXE-related ophthalmic abnormalities. MATERIALS AND METHODS: Thirty-eight of the 155 patients (57 male and 98 female aged 49±17 years) included in this retrospective study had optic nerve head drusen. All of the patients underwent a comprehensive ophthalmic examination, including color images using red-free, blue and red filters, autofluorescence imaging and late-phase ICG frames. Comparative analysis of both groups (optic nerve head drusen or not) was conducted using R statistical software. RESULTS: The prevalence of optic nerve head drusen in our cohort was 24.5%. In this study, no evidence of a significant link between optic nerve head drusen and other fundus abnormalities was detected. They were more commonly located in the nasal sector than in the temporal sector of the optic disc (P<0.001). They were more frequently situated superonasally than inferonasally (P<0.004), superotemporally (P<0.001) or inferotemporally (P<0.03). No central visual field defect was observed in OND+ patients who were unaffected by macular disorders. DISCUSSION: We hypothesized this predominantly nasal primary location may result from greater sensitivity in the nasal optic nerve fibers which follow a much more angular path once they arrive in the scleral canal, accounting for accumulation of axoplasmic debris. CONCLUSION: In PXE, optic nerve head drusen are mostly located in the superonasal quadrant, causing progressive optic nerve invasion but probably no central visual field defects.

[Glaucoma and optic nerve drusen: Limitations of optic nerve head OCT]. / Glaucome et drusen du nerf optique : les limites de l'OCT papillaire.

INTRODUCTION: Optic nerve head drusen are congenital calcium deposits located in the prelaminar section of the optic nerve head. Their association with visual field defects has been classically described, but the diagnosis of glaucoma is not easy in these cases of altered optic nerve head anatomy. CASE STUDY: We describe the case of a 67-year-old man with optic nerve head drusen complicated by glaucoma, which was confirmed by visual field and OCT examination of the peripapillary retinal nerve fiber layer (RNFL), but the measurement of the minimum distance between the Bruch membrane opening and the internal limiting membrane (minimum rim width, BMO-MRW) by OCT was normal. DISCUSSION: OCT of the BMO-MRW is a new diagnostic tool for glaucoma. Superficial optic nerve head drusen, which are found between the internal limiting membrane and the Bruch's membrane opening, overestimate the value of this parameter. CONCLUSION: BMO-MRW measurement is not adapted to cases of optic nerve head drusen and can cause false-negative results for this parameter, and the diagnosis of glaucoma in this case should be based on other parameters such as the presence of a fascicular defect in the retinal nerve fibers, RNFL or macular ganglion cell complex thinning, as well as visual field data.

OCT angiography of acute non-arteritic anterior ischemic optic neuropathy.

PURPOSE: To describe changes of the retinal peripapillary microvasculature on optical coherence tomography angiography (OCT-A) in non-arteritic anterior ischemic optic (NAION) neuropathy. METHODS: Observational study of 10 patients at the acute phase of NAION. OCT-A was performed using a 3mm×3mm square centered on the optic disc (Cirrus HD-OCT with Angioplex, Carl Zeiss Meditec, Dublin, CA). A qualitative comparison was made with the healthy fellow eye of each patient. All patients had a fluorescein angiography (HRA2, Heidelberg, Germany) and a visual field examination (Octopus 101®, Haag-Streit, USA). RESULTS: In the affected eyes, OCT-A showed clear modifications in the radial peripapillary network. In all these eyes, a focal disappearance of the superficial capillary radial pattern was present, twisted and irregular. In 8 eyes, there was also a lack of vascularization in some focal areas, appearing as dark areas. No correlation was found between the topography of the vascular alteration shown on OCT-A and visual field pattern defects. CONCLUSIONS: OCT-A is a new imaging technology able to demonstrate easily and safely the changes in the peripapillary capillary network during the acute phase of NAION. These changes are likely related to a decrease of the prelaminar optic nerve blood flow during the acute phase of NAION. Visual field defects are not correlated with OCT-A images, suggesting that they may be due mainly to disturbances in posterior ciliary artery blood flow.