Other common causes include diseases and disorders of the central nervous system, metabolic disorders and alcohol and drug toxicity. In the elderly, stroke is the most common cause. General diseases and conditions
Some of the diseases that present nystagmus as a pathological sign or symptom are as follows:

Aniridia
Benign paroxysmal positional vertigo

Toxicity or intoxication, metabolic disorders and combination
Sources of toxicity that could lead to nystagmus:

Thiamine deficiency
Risk factors for thiamine deficiency, or beri beri, in turn include a diet of mostly white rice, as well as alcoholism, dialysis, chronic diarrhea, and taking high doses of diuretics. Rarely it may be due to a genetic condition that results in difficulties absorbing thiamine found in food. Wernicke encephalopathy and Korsakoff syndrome are forms of dry beriberi. Central nervous system (CNS) diseases and disorders
Central nervous system disorders such as with a cerebellar problem, the nystagmus can be in any direction including horizontal. Purely vertical nystagmus usually originates in the central nervous system, but it is also an adverse effect commonly seen in high phenytoin toxicity. Other causes of toxicity that may result in nystagmus include:

Other causes
Non-physiological
Trochlear nerve malfunction
Vestibular Pathology (Ménières disease, SCDS (superior canal dehiscence syndrome), BPPV, Labyrinthitis)
Exposure to strong magnetic fields (as in MRI machines)
Long-term lack of light, called miners nystagmus after 19th-century coal miners who developed nystagmus from working in the dark. A slightly different form of nystagmus may be produced voluntarily by some people. Diagnosis
Nystagmus is highly noticeable but rarely recognized. Nystagmus can be clinically investigated by using a number of non-invasive standard tests.
There is currently uncertainty about the effectiveness of anaesthesia or analgesia for manual extraction, in terms of pain and the risk of postpartum haemorrhage. Very rarely a curettage is necessary to ensure that no remnants of the placenta remain (in rare conditions with very adherent placenta such as a placenta accreta). However, in birth centers and attended home birth environments, it is common for licensed care providers to wait for the placentas birth up to 2 hours in some instances. Other animals
Retention of fetal membranes (afterbirth) is observed more frequently in cattle than in other animals. In a normal condition, a cow’s placenta is expelled within a 12-hour period after calving. == References ==