The disease is a common eye disease with rapid onset, can involve both eyes, and has a high degree of visual impairment. It is characterized by a sudden loss of visual acuity, fan-shaped or hemianopic (mainly at the upper and lower levels) visual field defects and optic disc edema. It was first reported in 1879 by Cowers and uhfhoff in 1924, and was reported by Hayreh SS et al. in 1971-1975 based on fluorescein fundus angiography (FFA).
The disease is caused by acute ischemia of the optic disc due to impaired circulation in the posterior ciliary artery that feeds the optic disc, hence the name. Previously, it was also called ischemic optic papillopathy, acute ischemic optic disc lesion, ischemic optic papillitis, atherosclerotic optic papillitis, vascular pseudophakic optic papillitis, etc., and was commonly referred to as ophthalmoplegia. It is now gradually unified and standardized as anterior ischemic optic neuropathy.
Those caused by temporal arteritis are called arteritis anterior ischemic optic neuropathy, which is more common abroad but rarely reported in China. Those not caused by temporal arteritis are called non-arteritic anterior ischemic optic neuropathy (NAION). The incidence of NAION in the United States is 1.02:10,000 to 1:15,000, and in China, Xu Liang et al. first reported an annual incidence of 1:16,000 in the national population. the actual incidence may be higher due to the vast geographical area of China, differences in the physical and dietary habits of the population, and the lack of awareness among ophthalmology clinicians.
Although the etiology of NAION is not well understood, a number of systemic and local factors are closely related to the pathogenesis of NAION, and in-depth study of related factors is beneficial to the understanding of the etiology and the choice of treatment options. With the deepening of clinical understanding and research on NAION, early diagnosis and treatment can significantly reduce the blinding and disability rate of this disease.
The clinical manifestations are.
1, the age of onset: the majority of foreign patients in the elderly, the average age of 60 years or higher, in recent years there are reports of foreign patients aged less than 50 years. In China, the majority of patients are 40 to 82 years old, with an average of 49 or 53 years old, and few are under 35 years old. There is little difference in gender.
2, more than two eyes are involved, but often weeks to years apart. A foreign study concluded that 14% of the other eye develops within 5 years, and the authors observed that 48% of the contralateral eyes develop within 3 years without a visual cup.
3. The onset of the disease is rapid, occurring mostly in the morning, initially as a dark shadow above, below or regionally, and expanding to diffuse blurring in front of the eye for a few hours or days, with a loss of central vision. At the beginning of the disease, almost more than half of the patients’ visual acuity exceeds 0.6, and domestic statistics report that 51%~61% of patients have central visual acuity above 0.2, and 23% of patients have population visual acuity below 0.1, and some have low visual acuity or even index or light perception.
4, optic disc edema, can present the whole optic disc edema or regional edema, also can be regional at first, a few hours to a few days later into the whole optic disc edema; initially optic disc edema high up <1D, a few days can be elevated 2 ~ 3D, optic disc color basal light or above, below, and regional relative color light. There may be radioactive streaks and lines of hemorrhage at the edge of the optic disc. After the edema of the optic disc subsides, the color of the disc may become lighter regionally or completely, and part of it may show white atrophic changes.
5.Some patients have discomfort before or at the onset of the disease with dullness and swelling of the affected forehead or brow arch, but no painful eye rotation. Most patients do not feel any discomfort.
6.Foreign studies believe that the natural course of the disease takes 6 months from the onset to the stabilization of the disease, and the edema subsides in 7.9 weeks on average. Through careful study with the teacher, we can systematically and comprehensively diagnose the disease from western medicine diagnosis, and provide scientific basis and foundation for Chinese medicine evidence-based treatment to avoid misdiagnosis and other occurrences. The key to treatment is the rapid reduction of optic papillary edema. If the damage factor is relieved or the edema is removed in time, the optic nerve function will be restored and the central vision and visual field damage will be recoverable; if the damage persists and then leads to RNFL deficiency, the visual field deficiency will be irreversible.
Most of the nerve fibers in the ischemic area are irreversible in terms of degeneration and necrosis, while some of the nerve fibers in the ischemic area that are not completely necrotic lose their function due to edema, and if the edema rapidly subsides, some nerve fibers still recover their visual function to varying degrees, which is also illustrated by the fact that some patients change from absolute visual field defects to relative defects in the ischemic area in clinical practice. Therefore, continuous treatment and follow-up observation of patients according to different conditions are necessary.
(1) Glucocorticosteroids (steroids). Advantages: glucocorticoids are significantly effective in reducing edema and have an inhibitory effect on the expression of endothelin-1. Disadvantages: NAION patients all have varying degrees of primary diseases (hypertension, hyperlipidemia, diabetes, etc.), and the high dose and long-term use of hormones will aggravate the patient’s primary diseases, which in turn is not conducive to the recovery of NAION edema. We advocate early short-term application.
(2) vasodilator drugs Advantages: improve circulation, disadvantages: due to the physiological structure of the narrowed optic papilla, NAION edema period use, the patient’s optic disc will be in a crowded state due to the expansion of blood vessels, resulting in further edema due to blocked axoplasmic transport, resulting in deterioration of the condition, we recommend caution in the edema period.
(3) Dehydration agent Advantages: Increase intravascular colloid osmotic pressure, dehydration, diuresis, reduce intracranial pressure, accelerate the absorption and decompensation of edema Disadvantages: In clinical use, it is found that some patients have a tendency to aggravate edema during the use of the drug, and it has side effects on renal function, such as high blood viscosity, people with abnormal renal function should not use it.
(4) improve cellular energy metabolism drugs – calf blood deprotein extract advantages: enhance cellular uptake and utilization of oxygen and glucose, so that the anaerobic metabolism of glucose to aerobic metabolism, promote the synthesis of energy substances ATP increased, and at the same time promote and improve blood flow, conducive to neurological recovery, in the NAION edema period application effect is obvious. Disadvantages: expensive, some patients can not afford.
(5) Hyperbaric oxygen chamber is an adjuvant treatment, which has a positive effect on accelerating the absorption of edema.
(6) Optic nerve sheath decompression has proven to be ineffective and is rarely used.
(7) Plant neuromodulators Compound camptothecin can accelerate the restoration of the normal level of vasoactive substances in the ischemic area. However, when to apply it during the edema period or the period when the edema subsides is more effective needs to be further studied.
(8) IOP-lowering drugs have a positive effect on preventing the onset of disease.
(9) Application of neurorestorative agents The following are commonly used: . Cytophosphorylcholine, cerebroprotein hydrolysate, ganglioside, disodium cytidine triphosphate, nerve growth factor, etc. The best time to apply them is after the basic subsidence of optic papillary edema.
(10) Other therapies. the occurrence of NAION is closely related to systemic diseases such as hypertension and diabetes, as well as physiological and pathological states such as hemodynamics, local anatomy (small optic disc, optic cup stenosis), high blood viscosity, and low ocular perfusion pressure. For this multifactorial disease, it is often difficult to achieve satisfactory results with the use of one or several drugs alone. According to the characteristics of the patient’s condition, active treatment of primary diseases, such as adjustment of blood glucose, blood pressure, lipids; carrier oxygen, hyperbaric oxygen to improve the hemodynamic shear rate, and the use of diphenhydramine are the basis for better results.
Therefore, systemic basic treatment is performed along with local treatment, and the recovery of central vision in NAION patients is remarkable after improving systemic abnormal blood rheology by drugs. These western medical treatments need to be combined with the holistic concept of TCM, and a comprehensive and systematic treatment idea and approach is also reflected in the treatment of the disease, which shows that the treatment of the disease is closely linked in medical theory, as the eye localization, is a microcosm of the whole body as a whole, and these all reflect the cognitive thinking and discriminatory treatment view of TCM.