Optic nerve hemorrhage

Compared with the retrobulbar technique, peribulbar anesthesia provides similar anesthesia and akinesia for both anterior segment and vitreoretinal surgical procedures, but some patients may have inadequate akinesia and require additional injections. In addition, the onset time of blockade is not as rapid as with retrobulbar injection. Nevertheless, peribulbar anesthesia reduces the potential for inadvertent globe penetration, retrobulbar hemorrhage, and direct optic nerve injury. Although serious problems with retrobulbar and peribulbar injections are uncommon, numerous complications have been reported (Box 3-3). 

The visual acuity in posterior uveitis varies dramatically from case to case. Vitreitis, macular edema and/or exudate, subretinal neovascularization and/or hemorrhage, retinal detachment, and necrotic macular scarring may all serve to diminish acuity. In addition, the optic nerve may be involved in some infectious forms of posterior uveitis, such as toxoplasmosis, herpes, syphilis, or tuberculosis. Optic neuritis or neuroretinitis can further serve to compromise vision. 

Disc hemorrhages are an important prognostic indicator in the assessment and management of glaucoma and ocular hypertension. Glaucoma patients who develop disc hemorrhages are more likely to develop optic nerve... 

A primary lipidosis has been described in human optic nerves affected by amiodarone. One study has shown that intracytoplasmic inclusions may mechanically or biochemically block axoplasmic flow in large optic nerve axons, resulting in optic disc edema and hemorrhage. 

Factors that mimic glaucomatous visual field loss include branch retinal artery occlusion chorioretinal scars retinal areas treated by photocoagulafion or cryotherapy demyelin-afing disorders cerebrovascular accidents, tumors, or other lesions affecting the optic nerve, chiasm, optic tract, optic radiation, ancPor the remaining course of nerve fibers to the occipital cortex. Other abnormalities that could account for pseudo-glaucomatous visual field defects or vision loss include vitreous hemorrhage, proliferative retinopathy or other retinal disorders. 

Retinal vascular occlusion is rare, but it can occur in patients with severe vascular disease, without retrobulbar or optic nerve sheath hemorrhage the mechanism is unclear (SED-12, 254) (306). 

Cowley M, Campochiaro PA, Newman SA, Fogle JA. Retinal vascular occlusion without retrobulbar or optic nerve sheath hemorrhage after retrobulbar injection of lidocaine. Ophthalmic Surg 1988 19(12) 859-61. 

Regardless of the entry route, the major symptoms of thallium poisoning are gastrointestinal stress, neurological problems, and hair loss. Pain develops, fingers become numb, motor weakness is noted, and lower limbs may become paralyzed. The eyes become inflamed and retrobulbar neuritis with some loss of central vision follows. Intraocular hemorrhage, formation of cataracts, and optic nerve atrophy can occur. 

Figure 2 CRVO is characterized by retinal hemorrhages in all four quadrants, venular dilation, and frequent optic nerve edema. Nerve fiber layer infarcts and macular edema may be associated features with both types of retinal vascular occlusion. Abbreviation CRVO, central retinal vein occlusion.

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