Morphometric Analysis of the Ophthalmic and Central Retinal Arteries via the Endoscopic Endonasal Trans-ethmoidal Approach: Surgical Relevance of Vascular Components Within the Medial Intraconal Zones.

BACKGROUND: The endoscopic endonasal approach (EEA) offers a minimally invasive route to treat medial intraconal space (MIS) lesions. Understanding the configuration of the ophthalmic artery (OphA) and the central retinal artery (CRA) is crucial. METHODS: An EEA to the MIS was performed on 30 orbits. The description of the intraorbital part of the OphA was divided into 3 segments and classified as type 1 and type 2 and the MIS was divided into three surgical zones (A, B, C). The CRA's origin, course, and point of penetration (PP) were analyzed. The relationship between the position of the CRA in the MIS and the OphA type was analyzed. RESULTS: The OphA type 2 was present in 20% of specimens. The site of origin of the CRA from the OphA was found on the medial surface in type 1 and on the lateral surface of type 2. The point of penetrationof the central retinal arterywas found in 87% of the specimens on the inferomedial surface, just anterior to the inferior muscular trunk, at an average distance of 9.5 mm ± 1 from the globe and 17 mm ± 1.5 from the AZ. The presence of the CRA in Zone C was associated only with OphA type 1. CONCLUSIONS: OphA type 2 is a common finding and can compromise the feasibility of an EEA to the MIS. A detailed preoperative analysis of the OphA and CRA should be conducted prior to approaching the MIS due to the implications of the anatomical variations that can compromise safe intraconal maneuverability during an EEA.

Novel Acute Retinal Artery Ischemia and Reperfusion Model in Nonhuman Primates.

BACKGROUND AND PURPOSE: The retina, as an externally located neural tissue, offers unique advantages in investigating the effect of therapeutic intervention on the brain. In this study, we put forth a clinically relevant model of retinal ischemia and reperfusion in nonhuman primates. METHODS: Acute retinal artery ischemia and reperfusion was induced by injecting an autologous clot into the ophthalmic artery of adult rhesus monkeys, and recanalization was achieved by focal thrombolysis with tPA (tissue-type plasminogen activator). Digital subtraction angiography and fluorescein angiography were used to evaluate blood flow in the retina and the choroid. Electroretinogram, optical coherence tomography, and hematoxylin and eosin staining were used to evaluate the structure and function of the retina after ischemia. RESULTS: Digital subtraction angiography and fluorescein angiography images confirmed occlusion of the ophthalmic and central retinal arteries, as well as recanalization after tPA thrombolysis. Electroretinogram indicated retinal functional damage following ischemia, and thrombolysis partially rescued its impairment. Optical coherence tomography and hematoxylin and eosin staining revealed ischemia-induced changes in the retina, and tPA partially mitigated these damages. CONCLUSIONS: This novel acute retinal artery ischemia and reperfusion model in rhesus monkeys may closely simulate retinal ischemia/reperfusion in clinical practice and provide an optimal platform for screening neuroprotective strategies.

Control of retinal blood flow levels by selected combinations of cervical arterial ligations in rat.

The effect of various combinations of cervical arterial ligations (Combinations) on retinal blood flow (RBF) levels is not known in rats. We hypothesized: 1) No artery exists between the Circle of Willis and the eye, 2) Selective Combinations enable varying RBF levels between normal and zero, 3) In certain Combinations, the capillary bed of the head participates in supplying the eye. Twenty-six Combinations were studied in one eye of 20 Long-Evans rats under general anesthesia. RBF was quantitatively evaluated with our published imaging methods based on direct measurements of venous diameter and blood velocity from the displacement of fluorescent microspheres over time. For each Combination, one or more RBF values (runs) were measured. Data were obtained from 59 runs (2.9 ± 2.7 runs/rat). Levels of RBF ranged from normal to zero. An artery between the Circle of Willis and the eye was excluded. With some Combinations, flow traversed the capillary bed. Combinations were consolidated into five Groups based on the blood flow paths remaining after the ligations. A mixed linear model accounting for multiple measurements in the same eye demonstrated an effect of Group on RBF (P < 0.0005). By major source of ocular blood supply, the trend of RBF levels was: ipsilateral carotid artery > contralateral carotid artery > ipsilateral distal internal carotid artery retrograde from Circle of Willis. The findings advanced knowledge of the sources of blood supply to the rat eye and demonstrated a method of selective cervical arterial ligations for varying RBF levels with potential to impact future retinal ischemia research.

Microsurgical Anatomy of the Central Retinal Artery.

BACKGROUND: The central retinal artery (CRA) has been described as one of the first branches of the ophthalmic artery.It arises medial to the ciliary ganglion and after a sinuous path within the orbital cavity it penetrates the lower surface of the dura mater that covers the optic nerve, approximately 1 cm behind the eyeball. However, the numerous anatomic descriptions that were made of the CRA have been insufficient or unclear in relation to certain characteristics that are analyzed in the present study. METHODS: An electronic literature search was made in the PubMed database and a cadaver dissection was performed on 11 orbits fixed in formaldehyde. RESULTS: Results were obtained regarding the source, collateral branches, curves, direction, length of the optic nerve, dural perforation site, distance, path and relations, diameter, and area of the central artery of the retina. CONCLUSIONS: Our anatomic study innovates in 2 aspects of the CRA: area and curves. Not only was there a simple count of the number of curves, but it also analyzed the angle presented by each of the curves based on photos obtained in high definition, with a digital program to reduce the margin of error. These curvatures of the CRA were classified according to their spatial disposition within the orbital cavity based on a pattern that was easy to understand. Data were obtained from the area of the CRA on the penetration of the CRA into the dural sheath of the optic nerve.

Laser therapy versus observation for symptomatic retinal artery macroaneurysms.

PURPOSE: The optimal management approach to retinal arterial macroaneurysms (RAM) is unknown. This paper compares long-term outcomes in RAM treated with laser therapy versus observation. METHODS: This is an IRB-approved retrospective study of patients with symptomatic RAM. Charts of patients with a diagnosis of RAM causing symptomatic visual loss were reviewed. Patients with less than 6 months follow up, other confounding diagnoses, or additional therapy beyond thermal laser were excluded. Statistical analysis was done using χ(2) or Student's t test as appropriate. RESULTS: Forty-eight patients with RAM were identified and 27 were included in the study (13 treated, 14 observed). Mean visual acuity in the observation group improved from 20/120 to 20/96 (p = 0.53) compared to 20/280 to 20/54 (p = 0.0003) in the treated group. Subgroup analysis showed that visual acuity in primarily hemorrhagic lesions treated with laser therapy improved by 1.21 logMAR compared to a loss of 0.11 logMAR (p = 0.002) in those that were observed. In primarily exudative lesions, both treated and observed lesions showed an improvement of 0.32 logMAR. No patients in the treatment group had a final visual acuity below 20/200 compared to four in the observation group. CONCLUSION: Treatment with direct laser photocoagulation was associated in this study with greater improvement in visual acuity and may decrease the risk of severe visual loss especially in primarily hemorrhagic RAM lesions. Compared to observation alone.

[Retinal Arterial Macroaneurysms (RAM)--pathology, differenzial diagnoses, and therapy]. / Retinale arterielle Makroaneurysmen (RAM)--Pathologie, Differenzialdiagnose und Therapie.

Retinal arterial macroaneurysms (RAM) are unilateral, solitary, acquired saccular or fusiform dilatations of the large arterioles of the retina, usually within the first three orders of bifurcation. They are associated with systemic vascular conditions such as hypertension and arteriosclerotic disease and occur most commonly in elderly women. Cases of simple RAM are predominated by the vascular ectasia. These macroaneurysms regress without treatment and without causing decreased visual acuity and will usually remain undetected. Complex RAM often go along with vision loss due to haemorrhage or oedema affecting the macula. Poor visual outcome may occur secondary to foveal exudates and subfoveal haemorrhage, the latter appear as pre-retinal, intra-, and subretinal haemorrhage. This overview discusses conservative and surgical therapeutic options for complex cases.

Obstrucción de arteria central de la retina / Central retinal artery occlusión

La obstrucción de la arteria central de la retina (OACR) es una emergencia oftalmológica. La mejor prueba de esto es que más de 75% de los pacientes sufren una importante pérdida visual con una agudeza visual de 20/400 o peor (5). Esto resulta en una reducción de la capacidad funcional y calidad de vida del paciente. También se asocia a un mayor riesgo de accidente cerebrovascular y enfermedades isquémicas del corazón. No existe un tratamiento 100% efectivo en la actualidad, aunque el uso del activador del plasminógeno tisular ha sido utilizado en dos ensayos clínicos controlados. En este artículo de revisión pretendemos describir la etiopatogenia, fisiopatología, además de discutir los tratamientos actuales que podemos ofrecer a nuestros pacientes (AU)

Obstruction of the central artery of the retina (CRAO) is an ophthalmological emergency. The best proof of this is that more than 75% of the patients suffer from a significant visual loss with a visual acuity 20/400 or worse. This results in a reduction of the functional capacity and quality of life to these patients. Also associated to a greater risk of stroke and ischemic heart disease. There is not exist a treatment 100% effective today, although the use of the activator of the Tissue plasminogen has been used in two controlled clinical trials. In this article we will describe the pathogenesis, pathophysiology and discuss current treatments that we can offer to our patients (AU)

Macroaneurisma retiniano tratado con laser e Implante intravítreo de Dexametadona (Ozurdex®) / Retinal macroaneurysm treated with láser and intravitreal implant of dexamethasone (Ozurdex®)

Caso Clínico. Presentamos un caso de una mujer que tras sufrir un macroaneurisma (MA) retiniano complicado con hemorragia y exudación retiniana, recibió tratamiento con láser argón y un implante intravítreo de dexametasona (Ozurdex®, Allergan). Se reabsorbe la exudación retiniana y se recupera rápidamente la agudeza visual. Discusión. Los macroaneurismas arteriales retinianos son dilataciones aneurismáticas adquiridas de las ramas arteriales retinianas que ocurren en el polo posterior. Cuando la mácula se ve amenazada con edema o exudación, se debe realizar un diagnóstico y tratamiento precoz con fotocoagulación láser. El implante intravítreo de dexametasona (Ozurdex®) podría ser útil para reducir la exudación macular y permitir una pronta recuperación visual (AU)

Case Report. We present a case of a woman that after suffering a retinal macroaneurysm complicated with hemorrhage and macular exudation, received treatment with argon Láser and intravitreal implant of dexamethasone (Ozurdex®,Allergan). The macular exudation was resolved and the visual acuity was prompted reestablished. Discussion. Retinal arterial macroaneurysm is an aneurismatic acquired dilatation of retinal arterial branches that occurs in the posterior fundus. When macular edema or hard exudates threatens or involves the fovea, prompt diagnosis and early treatment using Láser photocoagulation are indicated. Intravitreal implant of dexamethasone (Ozurdex®) might be useful in reduction of macular exudation and led a prompted visual recuperation (AU)

Simultaneous vitreous hemorrhage and branch retinal artery occlusion after prepapillary arterial loop rupture.

Prepapillary arterial loops are rare benign congenital vascular anomalies that may be complicated by vitreous hemorrhage and branch retinal artery occlusion (BRAO). We describe the first case in the literature of simultaneous occurrence of both these complications in the same eye of a patient with a bilateral prepapillary arterial loop, successfully treated with vitrectomy.

Assessment of retinal and choroidal blood flow changes using laser Doppler flowmetry in rats.

PURPOSE: A new noninvasive laser Doppler flowmetry (LDF) probe (one emitting fiber surrounded by a ring of eight collecting fibers, 1-mm interaxis distance) was tested for its sensitivity to assess the retinal/choroidal blood flow variations in response to hypercapnia, hyperoxia, diverse vasoactive agents and following retinal arteries photocoagulation in the rat. MATERIALS AND METHODS: After pupil dilation, a LDF probe was placed in contact to the cornea of anesthetized rats in the optic axis. Hypercapnia and hyperoxia were induced by inhalation of CO(2) (8% in medical air) and O(2) (100%) while pharmacological agents were injected intravitreously. The relative contribution of the choroidal circulation to the LDF signal was estimated after retinal artery occlusion by photocoagulation. RESULTS: Blood flow was significantly increased by hypercapnia (18%), adenosine (14%) and sodium nitroprusside (16%) as compared to baseline values while it was decreased by hyperoxia (-8%) and endothelin-1 (-11%). Photocoagulation of retinal arteries significantly decreased blood flow level (-45%). CONCLUSIONS: Although choroidal circulation most likely contributes to the LDF signal in this setting, the results demonstrate that LDF represents a suitable in vivo noninvasive technique to monitor online relative reactivity of retinal perfusion to metabolic or pharmacological challenge. This technique could be used for repeatedly assessing blood flow reactivity in rodent models of ocular diseases.

Angiography with a multifunctional line scanning ophthalmoscope.

A multifunctional line scanning ophthalmoscope (mLSO) was designed, constructed, and tested on human subjects. The mLSO could sequentially acquire wide-field, confocal, near-infrared reflectance, fluorescein angiography (FA), and indocyanine green angiography (ICGA) retinal images. The system also included a retinal tracker (RT) and a photodynamic therapy laser treatment port. The mLSO was tested in a pilot clinical study on human subjects with and without retinal disease. The instrument exhibited robust retinal tracking and high-contrast line scanning imaging. The FA and ICGA angiograms showed a similar appearance of hyper- and hypo-pigmented disease features and a nearly equivalent resolution of fine capillaries compared to a commercial flood-illumination fundus imager. An mLSO-based platform will enable researchers and clinicians to image human and animal eyes with a variety of modalities and deliver therapeutic beams from a single automated interface. This approach has the potential to improve patient comfort and reduce imaging session times, allowing clinicians to better diagnose, plan, and conduct patient procedures with improved outcomes.

Morphologic characteristics of retinal arterial macroaneurysm and its regression pattern on spectral-domain optical coherence tomography.

PURPOSE: To investigate morphologic characteristics of retinal arterial macroaneurysm (RAM) and its regression pattern using spectral-domain optical coherence tomography. METHODS: This observational case series included six eyes of six patients with RAM. All patients had undergone repeated comprehensive ophthalmologic examination, including measurement of best-corrected visual acuity, slit-lamp biomicroscopy, indirect fundus examination, fundus photography, fluorescein angiography, and spectral-domain optical coherence tomography (Spectralis OCT). Morphologic findings of RAM on spectral-domain optical coherence tomography and changes after treatment were investigated. RESULTS: On initial diagnosis, eyes with RAMs showed a round hyperreflective wall with a hyporeflective lumen on spectral-domain optical coherence tomography. Five of six patients underwent direct laser photocoagulation to the RAM. One hour after treatment, the lumen of the RAM showed a homogeneous high reflectance, indicating occlusion with thrombus. One or 2 months after treatment, spectral-domain optical coherence tomography demonstrated almost entirely obliterated RAMs and decreased perianeurysmal retinal edema. One patient showed spontaneous rupture and involution of RAM. Superficial location of RAM was associated with hemorrhagic complications. CONCLUSION: Spectral-domain optical coherence tomography can show morphologic characteristics of RAM and structural changes after treatment. These new findings can be valuable not only in clinical diagnosis but also in predicting the treatment response of RAM.

[Diagnosis of systemic disease after bilateral retinal arterial macroaneurysm]. / Diagnóstico de patología sistémica tras macroaneurisma arterial retiniano bilateral.

CASE REPORT: An 85 year old male suffered vision loss in both eyes due to ruptured bilateral retinal arterial macroaneurysms. DISCUSSION: We report this unusual case and show the importance of studying these types of patients in order to detect associated systemic diseases.

Improving the therapeutic window of retinal photocoagulation by spatial and temporal modulation of the laser beam.

Decreasing the pulse duration helps confine damage, shorten treatment time, and minimize pain during retinal photocoagulation. However, the safe therapeutic window (TW), the ratio of threshold powers for thermomechanical rupture of Bruch's membrane and mild coagulation, also decreases with shorter exposures. Two potential approaches toward increasing TW are investigated: (a) decreasing the central irradiance of the laser beam and (b) temporally modulating the pulse. An annular beam with adjustable central irradiance was created by coupling a 532-nm laser into a 200-µm core multimode optical fiber at a 4-7 deg angle to normal incidence. Pulse shapes were optimized using a computational model, and a waveform generator was used to drive a PASCAL photocoagulator (532 nm), producing modulated laser pulses. Acute thresholds for mild coagulation and rupture were measured in Dutch-Belted rabbit in vivo with an annular beam (154-163 µm retinal diameter) and modulated pulse (132 µm, uniform irradiance "flat-top" beam) with 2-50 ms pulse durations. Thresholds with conventional constant-power pulse and a flat-top beam were also determined. Both annular beam and modulated pulse provided a 28% increase in TW at 10-ms duration, affording the same TW as 20-ms pulses with conventional parameters.

[Retinal arterial macroaneurysm complicated by premacular hemorrhage: treatment by YAG laser disruption]. / Macro-anévrysme artériel rétinien compliqué d'une hémorragie prérétinienne: traitement par photocoagulation au laser YAG.

INTRODUCTION: Retinal arterial macroaneurysms are ectatic modifications of the arterial wall. They are a relatively uncommon condition that can threaten visual function by pre- or subretinal hemorrhage if rupture or massive macular exudation occurs. OBSERVATION: We report a case of a 59-year-old patient with arterial hypertension who presented an arterial macroaneurysm complicated by premacular hemorrhage. We performed Nd: YAG laser photodisruption, which resulted in drainage of preretinal blood, with complete hemorrhage regression and visual recovery. COMMENTS AND CONCLUSION: Retinal macroaneurysms are acquired malformations, often isolated and located in a temporal artery. Their progression is unpredictable, evolving toward spontaneous occlusion, occurrence of chronic exudative retinopathy, or hemorrhagic complications by fissuration or rupture of the arterial wall. Through this observation, the authors discuss the value of YAG laser photodisruption for preretinal hemorrhage caused by retinal macroaneurysm.