Introduction. - analysis of the various retinal structures enables a clinical diagnosis to be made before resorting to paraclinical investigations.
Purpose. - The objective of the study is to analyze the epidemiological profile of the Moroccan ophthalmological pathology, to reveal the new clinical signs in ocular and general diseases, and to extend the field of interest of ophthalmoscopy in internal medicine using an algorithmic diagnostic tree in the medical examination.
Material and methods. - This is a prospective study of 500 patients divided into 3 cohorts: Cohort A, 115 patients recruited through the ophthalmic consultation. Cohort B, 122 patients referred by the other medico-surgical specialties for a fundus examination. Cohort C, 263 healthy volunteers. Each patient was entitled to a clinical record card including his group type, identity, history, risk factors, and findings of the ophthalmologic examination. finally, retinal photography is taken for a detailed analytical study. All data collected was entered into a computer operating grid from Access database software.
Results. - The results were analyzed using a computerized database to compare Moroccan ophthalmological pathology with data from the international literature for cohort A, to search for new retinal signs of ocular and general diseases added to the basal nucleus for cohort B and to identify unknown retinal signs for cohort C.
Comments. - The information collected in the three groups are to be appreciated as an enrichment of ophthalmologic semiology. The analytical study has resulted in the fact that the new clinical signs found in the fundus for patients allocated to the cohort B have the same pathogenesis as the primary disease. Concerning patients in cohort C, certain vascular anomalies are considered physiological variants of unknown causes, but the search for a quiescent vascular pathology is imperative.
Conclusion. -This research study insists on highlighting the semiology of fundus lesions exams to help clinical diagnosis. The fundus examination offers a direct visualization of the various elements of retina, thus allowing the search for retinal clinical signs that help in the diagnosis of ocular or general diseases.

Types and Mechanisms of Postoperative Visual Loss
Blindness following anesthesia can result from several distinct pathophysiological mechanisms, each affecting different parts of the visual pathway.
Ischemic Optic Neuropathy
Ischemic optic neuropathy (ION) is the most frequently reported cause of postoperative visual loss, particularly after spinal fusion and cardiac surgeries[1][2]. It results from impaired blood supply to the optic nerve and is classified into two main types:
Anterior Ischemic Optic Neuropathy (AION)
AION affects the anterior portion of the optic nerve where it enters the ocular globe. It presents with painless vision loss that may be unilateral or bilateral with symptoms ranging from no light perception to color vision deficits and visual field defects[1]. Fundoscopic examination typically reveals optic disc edema and flame-shaped hemorrhage upon symptom onset[1]. The onset of symptoms in AION is typically reported within one to two days after surgery, although it may be delayed by up to 12 days postoperatively, particularly in sedated patients requiring mechanical ventilation[1][3].
Posterior Ischemic Optic Neuropathy (PION)
PION involves the retrobulbar portion of the optic nerve and is an uncommon but well-documented cause of POVL. Unlike AION, the optic disc often appears normal initially in PION cases, with mild disc edema developing days later[1][4]. PION occurs spontaneously less frequently than AION but is reported with greater frequency in postoperative patients associated with hemorrhagic hypotension and in anemic patients after severe hypotension[5]. The posterior optic nerve is particularly vulnerable to ischemia at the orbital apex, the point of the nerve's entry where it is farthest from arterial supply, being nourished only by centripetal pial vessels that can be readily compressed[5].
Central Retinal Artery Occlusion
Central retinal artery occlusion (CRAO) is another common cause of POVL, resulting from blockage of the central retinal artery leading to retinal hypoperfusion, rapidly progressive cellular damage, and vision loss[1]. The most common cause of perioperative retinal arterial occlusion is improper patient positioning resulting in external compression of the eye, which produces sufficient intraocular pressure to stop flow in the central retinal artery[6]. This complication is particularly seen in spine surgery performed with patients in the prone position[7][6].
Cortical Blindness
Cortical blindness results from damage to the visual cortex or optic radiations in the brain rather than the eye or optic nerve. It is often associated with neurological manifestations such as nausea, motility, and sensory defects[8]. This type of POVL may be related to embolic phenomena, stroke, cerebral vascular accidents, meningitis, or perinatal or acquired hypoxia[8]. Cases of cortical blindness have been reported following orthopedic, spinal, and cardiac surgeries, with a higher incidence in patients younger than 18 years[8].
Risk Factors for Postoperative Visual Loss
Multiple studies have identified various risk factors associated with the development of POVL. Understanding these factors is crucial for developing effective prevention strategies.
Patient-Related Risk Factors
Several patient characteristics have been associated with increased risk of POVL:
· Male sex: Studies have consistently shown that male patients have a significantly higher risk of developing ION after major surgeries[9][10]
· Obesity: Higher body mass index is associated with increased risk of POVL[9][10]
· Comorbidities: Diabetes, hypertension, atherosclerosis, hyperlipidemia, sleep apnea, and hypercoagulability all increase the risk of postoperative blindness[7][10][6]
· Smoking history: Active smokers have an elevated risk of vascular complications including POVL[7][6]
· Low cup-to-disc ratio: This anatomical variation has been associated with increased susceptibility to AION[7][6]
Surgery-Related Risk Factors
The type and conditions of surgery significantly impact the risk of POVL:
· Type of surgery: The highest rates of POVL are reported after cardiac and spinal surgeries, particularly spinal fusion procedures[1][10]
· Positioning: Prone positioning significantly increases the risk of POVL, especially when the head is positioned lower than the heart[7][9]
· Use of the Wilson frame: This surgical frame has been associated with increased risk of ION[7][10]
· Duration of surgery: Longer anesthetic length is associated with an increased risk of POVL[7][9]
· Blood loss: Greater estimated blood loss during surgery elevates the risk of POVL[9][10]
Anesthesia-Related Risk Factors
Several anesthesia management factors contribute to the risk of POVL:
· Hypotension: Perioperative hypotension, particularly prolonged episodes, can compromise optic nerve perfusion[1][5][7]
· Anemia: Perioperative anemia reduces the oxygen-carrying capacity of blood, potentially contributing to ischemic damage[5][6]
· Hemodilution: Excessive hemodilution can compromise oxygen delivery to tissues including the optic nerve[7][6]
· Use of vasopressors: These medications may affect the microcirculation of the optic nerve[7][6]
· Lower percent of colloid in non-blood replacement: The ratio of crystalloid to colloid replacement may influence the development of POVL[10]
Prevention Strategies
Given the poor prognosis and limited treatment options for POVL, prevention is paramount.
Preoperative Assessment
Thorough preoperative evaluation is essential for identifying high-risk patients:
· Identify patients with risk factors such as male sex, obesity, and vascular comorbidities
· Consider preoperative discontinuation of medications that may increase risk, such as erectile dysfunction medications[7]
· Document any history of previous visual problems[11]
· Evaluate patients for the presence of vascular disease or diabetes[11]
Intraoperative Management
Several intraoperative strategies may reduce the risk of POVL:
· Careful positioning to avoid direct ocular pressure and excessive head-down positioning
· Proper padding of the eyes, particularly in prone-positioned patients
· Regular checks to ensure the eyes remain free from compression
· Hemodynamic monitoring and management to avoid prolonged hypotension
· Maintenance of adequate hemoglobin levels during procedures associated with significant blood loss
· Avoidance of intraoperative hyperventilation, which can affect cerebral perfusion[7]
· Minimizing the duration of surgery when possible
Postoperative Surveillance
Early detection of POVL may improve outcomes:
· Visual evaluation following high-risk procedures
· Prompt ophthalmologic consultation for any visual complaints
· Increased awareness of the potential for delayed presentation of symptoms, particularly in sedated patients
Management of Postoperative Visual Loss
Despite various attempted treatments, management of established POVL remains challenging, with limited evidence supporting specific interventions.
Immediate Interventions
When POVL is suspected:
· Urgent ophthalmologic consultation should be sought to establish the diagnosis and decide on therapy[5]
· Diagnostic workup may include funduscopic examination, visual field testing, and in some cases visual evoked potentials
· For ischemic optic neuropathy, osmotic diuretics and high-dose steroids in the first 48 hours after the ischemic insult may decrease nerve fiber edema and assist residual circulation in the anterior optic nerve[5]
· For cortical blindness, management focuses on addressing the underlying cause such as cerebral hypoperfusion or embolic events
Long-term Management
The prognosis for recovery varies:
· AION: Most common outcome is little recovery of visual function, despite the return of normal choroidal circulation after 2-3 weeks. However, partial spontaneous remission has been reported in some cases[5]
· PION: The visual prognosis is generally poor, with limited recovery in most cases[4][12]
· Cortical blindness: Prognosis for recovery may be better than for ION, particularly in younger patients[8][13]
Prognosis and Outcomes
The long-term outcomes of POVL vary depending on the underlying cause:
· ION often results in permanent visual impairment with limited recovery[5][4]
· CRAO typically leads to severe permanent visual loss in the affected eye[7]
· Cortical blindness has a more variable prognosis, with some studies reporting good recovery rates, particularly in younger patients[8][13]
In a study of cats with postanesthetic cortical blindness, 14 out of 20 had documented recovery of vision, while 4 remained blind and 2 were lost to follow-up[13]. This suggests that the prognosis for recovery from cortical blindness may be better than for other forms of POVL.