Ahmed Almanjoumi

University Joseph Fourier - Grenoble 1, Grenoble, Rhône-Alpes, France

Are you Ahmed Almanjoumi?

Claim your profile

Publications (6)14.1 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In non-arteritic anterior ischaemic optic neuropathy (NAAION) patients, circulatory insufficiency within the optic nerve has previously been hypothesized to be related to nocturnal systemic hypotension. The main objective of this prospective cohort study was to investigate the nyctohemeral variations in ocular perfusion pressure (OPP) in NAAION patients. In 20 patients with NAAION, the intraocular pressure (IOP) was measured using the Tono-Pen XL(™) electronic tonometer every hour for 24 hr. Blood pressure (BP) was evaluated over 24 hr. Mean OPP was calculated with the following formula: OPP sitting position = (0.74 × mean BP) - IOP and OPP lying position = (0.84 × mean BP) - IOP. A nonlinear least squares dual-harmonic regression analysis approach was used to model the 24-hr rhythms of OPP data. On average, a 24-hr amplitude of 4.7 ± 2.6 mmHg was found for OPP. The patients were classified as either having a diurnal OPP rhythm (i.e. with a diurnal acrophase, 10% of the cases), a nocturnal OPP rhythm (45%) or absence of OPP rhythm (45%). Four patients had a nocturnal reduction in OPP (mean, -11%). The physiological nocturnal rhythm of OPP was maintained in 45% of the NAAION patients. The nocturnal reduction in OPP seen in 20% of the patients was within the range of OPP where optic nerve blood flow autoregulation is still fully operative. A high prevalence of obstructive sleep apnoea syndrome in our population (71%) may explain the low frequency of systemic nocturnal hypotension.
    Acta ophthalmologica 01/2014; · 2.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: This study investigates the effect of increased ocular perfusion pressure (OPP), on optic nerve head (ONH) hemodynamics. Methods: In 21 healthy subjects, the increase in arterial blood pressure (BP), measured continuously using a pneumatic transcutaneous sensor Nexfin™, was produced by isometric exercise consisting of 2 minutes of handgripping. ONH blood flow parameters, namely the velocity (Vel), number (Vol), and flux (F) of red blood cells, were measured using the laser Doppler flowmeter (LDF). Results: In those 14 healthy subjects who exhibited an homogeneous increase in BP to handgrip superior to 30% of baseline BP, group average increases of BP and OPP amounted to 34 ±3 (SEM)% and 43 ±3%, respectively. The F increase of 19 ±8%, resulting from an increase in Vel (17 ±7%) and Vol (6% ±7%), was significantly less than predicted for a passive autoregulatory response, as revealed also by the increase in vascular resistance. The closed-loop gain (G) of the regulatory process was found to be rather independent from the OPP, with an average value 0.7 ±0.07. G was 0.83 ± 0.06 for the group of 8 subjects with stable F and 0.3 ±0.15 for the group of 6 subjects with F increasing with the OPP. Conclusions: The continuous recording of both BP and LDFs represents a novel and more precise approach to the characterization of ONH hemodynamics during isometric exercise, especially useful in the future for patients with ocular diseases. The efficiency of the ONH blood flow autoregulation appears to vary significantly between healthy subjects.
    Investigative ophthalmology & visual science 12/2013; · 3.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To report the safety and efficacy of 23-gauge (23-G) transconjunctival vitrectomy (TSV) in the surgical management of postoperative endophthalmitis. Ten consecutive patients underwent a 23-G TSV in 2008-2010 after cataract surgery (n = 5) or filtrating surgery (n = 5), and were prospectively studied with a minimum follow-up of 6 months. TSV was performed within a median delay of 1 day after the diagnosis, after one or two injections of intravitreal antibiotics (vancomycin, ceftazidime). Conventional cultures (brain heart infusion media) and/or panbacterial PCR were performed on aqueous humor and/or vitreous samples. Initial visual acuity was less than or equal to hand motion in all cases, and clinical findings included hypopyon (80%), pupillary fibrin membrane (80%), and dense vitreitis (4+, 100%). The bacteria identified were Gram-positive cocci in 60% of the cases (coagulase-negative staphylococci, 20%; streptococcus, 40%) and Gram-negative bacilli in 10% (moraxella lacunata). All patients had central and peripheral vitrectomy (mean duration, 58.6 ± 16 min). No intraoperative complications were noted. Two patients developed retinal detachment postoperatively and were reoperated. The final visual vision was 20/400 for two patients and 20/50 or better for the other patients. 23-G TSV allows the surgeon to meet the same objectives as the 20-G technique for the treatment of endophthalmitis.
    Albrecht von Graæes Archiv für Ophthalmologie 01/2012; 250(9):1367-71. · 1.93 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To assess 24-hour intraocular pressure (IOP) and ocular perfusion pressure rhythms in newly diagnosed apneic patients before and after nasal continuous positive airway pressure (nCPAP) treatment. Intraocular pressure (using a Tonopen XL) and ambulatory blood pressure, measured hourly for 24 hours, were analyzed in 18 consecutive patients with obstructive sleep apnea for nyctohemeral rhythmicity (cosinor model). Twelve of 18 patients were reassessed after nCPAP use. Before treatment, 28% of the patients with obstructive sleep apnea demonstrated a nocturnal acrophase, 22% a diurnal acrophase, and 50% absence of 24-hour rhythm of IOP. The ocular perfusion pressure rhythm was nocturnal in 78% of cases and absent in 22%. Using nCPAP, the mean (standard error of the mean) nocturnal IOP increased from 14.8 (0.8) to 18.3 (1.2) mm Hg (P < .03). Among patients with initial abnormal IOP rhythm (ie, rhythm with diurnal acrophase or absence of rhythm), 67% shifted to a normal 24-hour IOP profile after treatment. Normal IOP nyctohemeral rhythm is lost in most patients with severe apnea. Nasal continuous positive airway pressure use restored a normal 24-hour IOP profile in most cases.
    Archives of ophthalmology 10/2010; 128(10):1257-63. · 3.86 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose Obstructive sleep apnea syndrome (OSA) has been reported to be associated with ischemic and glaucomatous optic neuropathy (especially normal tension glaucoma). OSA per se is able to generate hypertension, atherosclerosis and autonomic dysfunction, all conditions possibly interacting with ocular vascular regulation. The aim of our study was to characterize the choroidal vascular reactivity to change in body position in OSA patients, as compared with matched healthy control subjects.Methods Eighteen newly diagnosed OSA patients were included in this prospective study. Control subjects were matched with OSA patients for body mass index (BMI), gender and age. At the screening visit, each subject underwent a general exam, cardiovascular, neurologic and ophthalmological examinations, and overnight polysomnography. The LDF instrument used in this study to measure subfoveal choroidal blood flow (ChBF), ChBVel , velocity (kHz); and volume, ChBVol (in arbitrary units, AU) Vascular choroidal reactivity was tested during the change in body position from the sitting to the supine position (10 min).Results OSA patients exhibited a similar choroidal reactivity during change in body position than controls with increased ChBVel (+15%), decreased ChBVol (-11.6%), and unchanged ChBF. IOP increased by 14.2% in the supine position whereas ocular perfusion pressure remained stable.Conclusion This prospective comparative study showed for the first time unimpaired choroidal vascular reactivity in otherwise healthy OSA patients. This suggests OSA patients, without comorbidities, has long-term adaptive mechanisms active in ocular microcirculation.
    Acta ophthalmologica 09/2010; 88(s246). · 2.44 Impact Factor
  • Journal Francais D Ophtalmologie - J FR OPHTALMOL. 01/2009; 32.