tailieunhanh - Chapter 029. Disorders of the Eye (Part 11)

Posterior Ischemic Optic Neuropathy This is an infrequent cause of acute visual loss, induced by the combination of severe anemia and hypotension. Cases have been reported after major blood loss during surgery, exsanguinating trauma, gastrointestinal bleeding, and renal dialysis. The fundus usually appears normal, although optic disc swelling develops if the process extends far enough anteriorly. Vision can be salvaged in some patients by prompt blood transfusion and reversal of hypotension. Optic Neuritis This is a common inflammatory disease of the optic nerve. In the Optic Neuritis Treatment Trial (ONTT), the mean age of patients was 32 years, 77% were. | Chapter 029. Disorders of the Eye Part 11 Posterior Ischemic Optic Neuropathy This is an infrequent cause of acute visual loss induced by the combination of severe anemia and hypotension. Cases have been reported after major blood loss during surgery exsanguinating trauma gastrointestinal bleeding and renal dialysis. The fundus usually appears normal although optic disc swelling develops if the process extends far enough anteriorly. Vision can be salvaged in some patients by prompt blood transfusion and reversal of hypotension. Optic Neuritis This is a common inflammatory disease of the optic nerve. In the Optic Neuritis Treatment Trial ONTT the mean age of patients was 32 years 77 were female 92 had ocular pain especially with eye movements and 35 had optic disc swelling. In most patients the demyelinating event was retrobulbar and the ocular fundus appeared normal on initial examination Fig. 29-10 although optic disc pallor slowly developed over subsequent months. Figure 29-10 gwcti Ftvci Lttpt DL. fertunvtkl i. Hovit 9L Longo C L- Jtmetori Jl Loic I Ji Hirrisen t fri tdpfts rf fr-ternst L7th Editioni http owy. oo -i ri d Copyright Th McGrt -H. l Compinrf . nt. All right rkinr. td. Retrobulbar optic neuritis is characterized by a normal fundus examination initially hence the rubric the doctor sees nothing and the patient sees nothing. Optic atrophy develops after severe or repeated attacks. Virtually all patients experience a gradual recovery of vision after a single episode of optic neuritis even without treatment. This rule is so reliable that failure of vision to improve after a first attack of optic neuritis casts doubt upon the original diagnosis. Treatment with high-dose IV methylprednisolone 250 mg every 6 h for 3 days followed by oral prednisone 1 mg kg per day for 11 days makes no difference in final acuity measured 6 months after the attack but the recovery of visual function occurs more rapidly. For some patients optic neuritis remains an .