If the diagnostic workup reveals a systemic disease process, directed therapies to treat that underlying cause should be initiated. If the amaurosis fugax is caused by an atherosclerotic lesion, aspirin is indicated, and a carotid endarterectomy considered based on the location and grade of the stenosis. Generally, if the carotid artery is still patent, the greater the stenosis, the greater the indication for endarterectomy. "Amaurosis fugax appears to be a particularly favorable indication for carotid endarterectomy. Left untreated, this event carries a high risk of stroke; after carotid endarterectomy, which has a low operative risk, there is a very low postoperative stroke rate." However, the rate of subsequent stroke after amaurosis is significantly less than after a hemispheric TIA, therefore there remains debate as to the precise indications for which a carotid endarterectomy should be performed. If the full diagnostic workup is completely normal, patient observation is recommended.

There is no cure for ONH; however, many therapeutic interventions exist for the care of its symptoms. These may include hormone replacement therapy for hypopituitarism, occupational, physical, and/or speech therapy for other issues, and services of a teacher of students with blindness/visually impairment. Special attention should be paid to early development of oral motor skills and acclimation to textured foods for children with texture aversion, or who are otherwise resistant to eating.

Sleep dysfunction can be ameliorated using melatonin in the evening in order to adjust a child's circadian clock.

Treatment for strabismus may include patching of the better eye, which may result in improved vision in the worse eye; however, this should be reserved for cases in which the potential for vision improvement in both eyes is felt to be good. Surgery to align the eyes can be performed once children with strabismus develop equal visual acuity in both eyes, most often after the age of three. Generally surgery results in improved appearance only and not in improved visual function.

Corneal collagen cross-linking is a developing treatment which aims to strengthen the cornea, however, according to a 2015 Cochrane review, there is insufficient evidence to determine if it is useful in keratoconus.

In 2016, the US Food and Drug Administration approved riboflavin ophthalmic solution and KXL system for crosslinking based on three 12-month clinical trials.

In early stages of keratoconus, glasses or soft contact lenses can suffice to correct for the mild astigmatism. As the condition progresses, these may no longer provide the person with a satisfactory degree of visual acuity, and most practitioners will move to manage the condition with rigid contact lenses, known as rigid, gas-permeable, (RGP) lenses. RGP lenses provide a good level of visual correction, but do not arrest progression of the condition.

In people with keratoconus, rigid contact lenses improve vision by means of tear fluid filling the gap between the irregular corneal surface and the smooth regular inner surface of the lens, thereby creating the effect of a smoother cornea. Many specialized types of contact lenses have been developed for keratoconus, and affected people may seek out both doctors specialized in conditions of the cornea, and contact lens fitters who have experience managing people with keratoconus. The irregular cone presents a challenge and the fitter will endeavor to produce a lens with the optimal contact, stability and steepness. Some trial-and-error fitting may prove necessary.

Prior to 1990, amaurosis fugax could, "clinically, be divided into four identifiable symptom complexes, each with its underlying pathoetiology: embolic, hypoperfusion, angiospasm, and unknown". In 1990, the causes of amaurosis fugax were better refined by the Amaurosis Fugax Study Group, which has defined five distinct classes of transient monocular blindness based on their supposed cause: embolic, hemodynamic, ocular, neurologic, and idiopathic (or "no cause identified") Concerning the pathology underlying these causes (except idiopathic), "some of the more frequent causes include atheromatous disease of the internal carotid or ophthalmic artery, vasospasm, optic neuropathies, giant cell arteritis, angle-closure glaucoma, increased intracranial pressure, orbital compressive disease, a steal phenomenon, and blood hyperviscosity or hypercoagulability."

Optic papillitis is a specific type of optic neuritis. Inflammation of the optic nerve head is called "papillitis" or "intraocular optic neuritis"; inflammation of the orbital portion of the nerve is called "retrobulbar optic neuritis" or "orbital optic neuritis". It is often associated with substantial losses in visual fields, pain on moving the globe, and sensitivity to light pressure on the globe. It is often an early sign of multiple sclerosis.

Papillitis may have the same appearance as papilledema. However, papillitis may be unilateral, whereas papilledema is almost always bilateral. Papillitis can be differentiated from papilledema by an afferent pupillary defect (Marcus Gunn pupil), by its greater effect in decreasing visual acuity and color vision, and by the presence of a central scotoma. Papilledema that is not yet chronic will not have as dramatic an effect on vision. Because increased intracranial pressure can cause both papilledema and a sixth (abducens) nerve palsy, papilledema can be differentiated from papillitis if esotropia and loss of abduction are also present. However, esotropia may also develop secondarily in an eye that has lost vision from papillitis. Retrobulbar neuritis, an inflamed optic nerve, but with a normal-appearing nerve head, is associated with pain and the other findings of papillitis. Pseudopapilledema is a normal variant of the optic disk, in which the disk appears elevated, with indistinct margins and a normal vascular pattern. Pseudopapilledema sometimes occurs in hyperopic individuals.

Workup of the patient with papillitis includes lumbar puncture and cerebrospinal fluid analysis. B henselae infection can be detected by serology. MRI is the preferred imaging study. An abnormal MRI is associated with a worse visual outcome.

Initial care in the hospital, as in the prehospital setting, aims to ensure adequate airway, breathing, cardiovascular function, and spinal immobilization. Imaging of the spine to ascertain presence of SCI may need to wait if emergency surgery is needed to stabilize a life-threatening injury. Acute SCI merits treatment in an intensive care unit, especially injuries to the cervival spinal cord. Patients with SCI need repeated neurological assessments and treatment by neurosurgeons.

If the systolic blood pressure falls below 90 mmHg within days of the injury, blood supply to the spinal cord may be reduced, resulting in further damage. Thus it is important to maintain the blood pressure using a central venous catheter, intravenous fluids, and vasopressors, and to treat cases of shock. Mean arterial blood pressure is measured and kept at 85 to 90 mmHg for seven days after injury. The treatment for shock from blood loss (hypovolemic shock) is different from that for neurogenic shock, and could harm people with the latter type, so it is necessary to determine why someone is in shock. However it is also possible for both causes to exist at the same time. Another important aspect of care is prevention of hypoxia (insufficient oxygen in the bloodstream), which could deprive the spinal cord of much-needed oxygen. People with cervical injuries may experience a dangerously slowed heart rate; treatment to speed it up include atropine and electrical cardiac pacing.

Swelling can cause further damage to the spinal cord by reducing the blood supply and causing ischemia, which can give rise to an ischemic cascade with a release of toxins that damages neurons. Thus treatment is often geared toward limiting this secondary injury. People are sometimes treated with drugs to reduce swelling. The corticosteroid drug methylprednisolone is commonly used within eight hours of the injury, but its use is controversial because of side effects. Studies have shown high dose methylprednisolone may improve outcomes if given within 6 hours of injury. However, the improvement shown by clinical trials has been inconclusive, and comes at the cost of increased risk of serious infection or sepsis, gastrointestinal bleeding, and pneumonia. Thus organizations that set clinical guidelines have increasingly stopped recommending methylprednisolone in the treatment of acute SCI.

Surgery may be necessary, e.g. to relieve excess pressure on the cord, to stabilize the spine, or to put vertebrae back in their proper place. In cases involving instability or compression, failing to operate can lead to worsening of the condition. Surgery is also necessary when something is pressing on the cord, such as bone fragments, blood, material from ligaments or intervertebral discs, or a lodged object from a penetrating injury. Although the ideal timing of surgery is still debated, studies have found that earlier surgical intervention (within 24 hours of injury) is associated with better outcomes. Sometimes a patient has too many other injuries to be a surgical candidate this early. Surgery is controversial because it has potential complications (such as infection), so in cases where it is not clearly needed (e.g. the cord is being compressed), doctors must decide whether to perform surgery based on aspects of the patient's condition and their own beliefs about its risks and benefits.

In cases where a more conservative approach is chosen, bed rest, cervical collars, immobilizing devices, and optionally traction are used. Surgeons may opt to put traction on the spine to remove pressure from the spinal cord by putting dislocated vertebrae back into alignment, but herniation of intervertebral disks may prevent this technique from relieving pressure. "Gardner-Wells tongs" are one tool used to exert spinal traction to reduce a fracture or dislocation and to immobilize the affected areas.

The type of treatment needed for dogs diagnosed with CM/SM depends on the severity of the condition and the age of the dog. Young dogs with clinical signs should be considered for surgical removal to minimize the progression of the disease as the dog ages. Older dogs with little or no clinical signs may be treated medically, rather than surgically. However, severe cases of CM/SM may require surgery regardless of age. The goal of surgery is syrynx decompression through restoration of normal cerebrospinal fluid circulation.

The surgical treatment of CM in dogs is described as "foramen magnum decompression FMD". Despite an approximately 80% success rate with this surgical technique, there is a 25% to 50% relapse, primarily due to excessive scar tissue formation at the decompression site. A cranioplasty may be performed instead, in which a plate, constructed using titanium mesh and bone cement, is fixed to the back of the skull following a standard FMD procedure. The procedure had been effective in humans. The postoperative relapse rate associated with the titanium cranioplasty procedure is less than 7%.

If non-pharmacological measures are not effective, medications may be tried.

- Non-steroidal anti-inflammatory drugs (NSAIDs) are typically tried first. NSAIDs have been shown to be more effective than placebo, and are usually more effective than paracetamol (acetaminophen).

- In severe back pain not relieved by NSAIDs or acetaminophen, opioids may be used. However, long-term use of opioids has not been proven to be effective at treating back pain. Opioids have not always been shown to be better than placebo for chronic back pain when the risks and benefits are considered.

- Skeletal muscle relaxers may also be used. Their short term use has been shown to be effective in the relief of acute back pain. However, the evidence of this effect has been disputed, and these medications do have negative side-effects.

- In people with nerve root pain and acute radiculopathy, there is evidence that a single dose of steroids, such as dexamethasone, may provide pain relief.

- Epidural corticosteroid injection (ESI) is a procedure in which steroid medications are injected into the epidural space. The steroid medications reduce inflammation and thus decrease pain and improve function. ESI has long been used to both diagnose and treat back pain, although recent studies have shown a lack of efficacy in treating low back pain.

In the majority of cases, spinal disc herniation doesn't require surgery, and a study on sciatica, which can be caused by spinal disc herniation, found that "after 12 weeks, 73% of people showed reasonable to major improvement without surgery." The study, however, did not determine the number of individuals in the group that had sciatica caused by disc herniation.

- Initial treatment usually consists of non-steroidal anti-inflammatory pain medication (NSAIDs), but the long-term use of NSAIDs for people with persistent back pain is complicated by their possible cardiovascular and gastrointestinal toxicity.

- Epidural corticosteroid injections provide a slight and questionable short-term improvement in those with sciatica but are of no long term benefit. Complications occur in 0 to 17% of cases when performed on the neck and most are minor. In 2014, the US Food and Drug Administration (FDA) suggested that the "injection of corticosteroids into the epidural space of the spine may result in rare but serious adverse events, including loss of vision, stroke, paralysis, and death." and that "The effectiveness and safety of epidural administration of corticosteroids have not been established, and FDA has not approved corticosteroids for this use.".

Non-surgical methods of treatment are usually attempted first, leaving surgery as a last resort. Pain medications are often prescribed as the first attempt to alleviate the acute pain and allow the patient to begin exercising and stretching. There are a variety of other non-surgical methods used in attempts to relieve the condition after it has occurred, often in combination with pain killers. They are either considered indicated, contraindicated, relatively contraindicated, or inconclusive based on the safety profile of their risk-benefit ratio and on whether they may or may not help:

The management of low back pain often includes medications for the duration that they are beneficial. With the first episode of low back pain the hope is a complete cure; however, if the problem becomes chronic, the goals may change to pain management and the recovery of as much function as possible. As pain medications are only somewhat effective, expectations regarding their benefit may differ from reality, and this can lead to decreased satisfaction.

The medication typically recommended first are NSAIDs (though not aspirin) or skeletal muscle relaxants and these are enough for most people. Benefits with NSAIDs; however, is often small. High-quality reviews have found acetaminophen (paracetamol) to be no more effective than placebo at improving pain, quality of life, or function. NSAIDs are more effective for acute episodes than acetaminophen; however, they carry a greater risk of side effects including: kidney failure, stomach ulcers and possibly heart problems. Thus, NSAIDs are a second choice to acetaminophen, recommended only when the pain is not handled by the latter. NSAIDs are available in several different classes; there is no evidence to support the use of COX-2 inhibitors over any other class of NSAIDs with respect to benefits. With respect to safety naproxen may be best. Muscle relaxants may be beneficial.

If the pain is still not managed adequately, short term use of opioids such as morphine may be useful. These medications carry a risk of addiction, may have negative interactions with other drugs, and have a greater risk of side effects, including dizziness, nausea, and constipation. The effect of long term use is unknown. Specialist groups advise against general long-term use of opioids for chronic low back pain.

For older people with chronic pain, opioids may be used in those for whom NSAIDs present too great a risk, including those with diabetes, stomach or heart problems. They may also be useful for a select group of people with neuropathic pain.

Antidepressants may be effective for treating chronic pain associated with symptoms of depression, but they have a risk of side effects. Although the antiseizure drugs gabapentin and carbamazepine are sometimes used for chronic low back pain and may relieve sciatic pain, there is insufficient evidence to support their use. Systemic oral steroids have not been shown to be useful in low back pain. Facet joint injections and steroid injections into the discs have not been found to be effective in those with persistent, non-radiating pain; however, they may be considered for those with persistent sciatic pain. Epidural corticosteroid injections provide a slight and questionable short-term improvement in those with sciatica but are of no long term benefit. There are also concerns of potential side effects.

Back pain is generally treated with non-pharmacological therapy first, as it typically resolves without the use of medication. Superficial heat and massage, acupuncture, and spinal manipulation therapy may be recommended.

- Heat therapy is useful for back spasms or other conditions. A review concluded that heat therapy can reduce symptoms of acute and sub-acute low-back pain.

- Regular activity and gentle stretching exercises is encouraged in uncomplicated back pain, and is associated with better long-term outcomes. Physical therapy to strengthen the muscles in the abdomen and around the spine may also be recommended. These exercises are associated with better patient satisfaction, although it has not been shown to provide functional improvement. However, one study found that exercise is effective for chronic back pain, but not for acute pain. If used, they should be performed under supervision of a licensed health professional.

- Massage therapy may give short-term pain relief, but not functional improvement, for those with acute lower back pain. It may also give short-term pain relief and functional improvement for those with long-term (chronic) and sub-acute lower pack pain, but this benefit does not appear to be sustained after 6 months of treatment. There does not appear to be any serious adverse effects associated with massage.

- Acupuncture may provide some relief for back pain. However, further research with stronger evidence needs to be done.

- Spinal manipulation is a widely-used method of treating back pain, although there is no evidence of long-term benefits.

- "Back school" is an intervention that consists of both education and physical exercises. A 2016 Cochrane review found the evidence concerning back school to be very low quality and was not able to make generalizations as to whether back school is effective or not.

Physical therapy can be somewhat useful for patient’s recovery from surgery. The main focus of rehabilitation is centered on controlling the bladder and bowel functions and decreasing muscle weakness in the lower extremities.

The management of true cauda equina syndrome frequently involves surgical decompression. When cauda equina syndrome is caused by a herniated disk early surgical decompression is recommended.

Cauda equina syndrome of sudden onset is regarded as a medical/surgical emergency. Surgical decompression by means of laminectomy or other approaches may be undertaken within 6, 24 or 48 hours of symptoms developing if a compressive lesion, e.g., ruptured disc, epidural abscess, tumour or haematoma is demonstrated. Early treatment may significantly improve the chance that long-term neurological damage will be avoided.

Surgery may be required to remove blood, bone fragments, a tumor or tumors, a herniated disc or an abnormal bone growth. If the tumor cannot be removed surgically and it is malignant then radiotherapy may be used as an alternative to relieve pressure, with spinal neoplasms chemotherapy can also be used. If the syndrome is due to an inflammatory condition e.g., ankylosing spondylitis, anti-inflammatory, including steroids can be used as an effective treatment. If a bacterial infection is the cause then an appropriate course of antibiotics can be used to treat it.

Cauda equina syndrome can occur during pregnancy due to lumbar disc herniation; age of mother increases the risk. Surgery can still be performed and the pregnancy does not adversely affect treatment. Treatment for those with cauda equina can and should be carried out at any time during pregnancy.

Lifestyle issues may need to be addressed post - treatment. Issues could include the patients need for physiotherapy and occupational therapy due to lower limb dysfunction. Obesity might also need to be tackled.

It is unclear if among those with non-chronic back pain alternative treatments are useful. For chiropractic care or spinal manipulation therapy (SMT) it is unclear if it improves outcomes more or less than other treatments. Some reviews find that SMT results in equal or better improvements in pain and function when compared with other commonly used interventions for short, intermediate, and long-term follow-up; other reviews find it to be no more effective in reducing pain than either inert interventions, sham manipulation, or other treatments, and conclude that adding SMT to other treatments does improve outcomes. National guidelines reach different conclusions, with some not recommending spinal manipulation, some describing manipulation as optional, and others recommending a short course for those who do not improve with other treatments. A 2017 review recommended spinal manipulation based on low quality evidence. Manipulation under anaesthesia, or medically assisted manipulation, has not enough evidence to make any confident recommendation.

Acupuncture is no better than placebo, usual care, or sham acupuncture for nonspecific acute pain or sub-chronic pain. For those with chronic pain, it improves pain a little more than no treatment and about the same as medications, but it does not help with disability. This pain benefit is only present right after treatment and not at follow-up. Acupuncture may be a reasonable method to try for those with chronic pain that does not respond to other treatments like conservative care and medications.

Massage therapy does not appear to provide much benefit for acute low back pain. A 2015 Cochrane review found that for acute low back pain massage therapy was better than no treatment for pain only in the short-term. There was no effect for improving function. For chronic low back pain massage therapy was no better than no treatment for both pain and function, though only in the short-term. The overall quality of the evidence was low and the authors conclude that massage therapy is generally not an effective treatment for low back pain.

Prolotherapy – the practice of injecting solutions into joints (or other areas) to cause inflammation and thereby stimulate the body's healing response – has not been found to be effective by itself, although it may be helpful when added to another therapy.

Herbal medicines, as a whole, are poorly supported by evidence. The herbal treatments Devil's claw and white willow may reduce the number of individuals reporting high levels of pain; however, for those taking pain relievers, this difference is not significant. Capsicum, in the form of either a gel or a plaster cast, has been found to reduce pain and increase function.

Behavioral therapy may be useful for chronic pain. There are several types available, including operant conditioning, which uses reinforcement to reduce undesirable behaviors and increase desirable behaviors; cognitive behavioral therapy, which helps people identify and correct negative thinking and behavior; and respondent conditioning, which can modify an individual's physiological response to pain. Medical providers may develop an integrated program of behavioral therapies. The evidence is inconclusive as to whether mindfulness-based stress reduction reduces chronic back pain intensity or associated disability, although it suggests that it may be useful in improving the acceptance of existing pain.

Tentative evidence supports neuroreflexotherapy (NRT), in which small pieces of metal are placed just under the skin of the ear and back, for non-specific low back pain.

SCI patients often require extended treatment in specialized spinal unit or an intensive care unit. The rehabilitation process typically begins in the acute care setting. Usually the inpatient phase lasts 8–12 weeks and then the outpatient rehabilitation phase lasts 3–12 months after that, followed by yearly medical and functional evaluation. Physical therapists, occupational therapists, recreational therapists, nurses, social workers, psychologists and other health care professionals work as a team under the coordination of a physiatrist to decide on goals with the patient and develop a plan of discharge that is appropriate for the person’s condition.

In the acute phase physical therapists focus on the patient’s respiratory status, prevention of indirect complications (such as pressure ulcers), maintaining range of motion, and keeping available musculature active.

For people whose injuries are high enough to interfere with breathing, there is great emphasis on airway clearance during this stage of recovery. Weakness of respiratory muscles impairs the ability to cough effectively, allowing secretions to accumulate within the lungs. As SCI patients suffer from reduced total lung capacity and tidal volume, physical therapists teach them accessory breathing techniques (e.g. apical breathing, glossopharyngeal breathing) that typically are not taught to healthy individuals. Physical therapy treatment for airway clearance may include manual percussions and vibrations, postural drainage, respiratory muscle training, and assisted cough techniques. Patients are taught to increase their intra-abdominal pressure by leaning forward to induce cough and clear mild secretions. The quad cough technique is done lying on the back with the therapist applying pressure on the abdomen in the rhythm of the cough to maximize expiratory flow and mobilize secretions. Manual abdominal compression is another technique used to increase expiratory flow which later improves coughing. Other techniques used to manage respiratory dysfunction include respiratory muscle pacing, use of a constricting abdominal binder, ventilator-assisted speech, and mechanical ventilation.

The amount of functional recovery and independence achieved in terms of activities of daily living, recreational activities, and employment is affected by the level and severity of injury. The Functional Independence Measure (FIM) is an assessment tool that aims to evaluate the function of patients throughout the rehabilitation process following a spinal cord injury or other serious illness or injury. It can track a patient's progress and degree of independence during rehabilitation. People with SCI may need to use specialized devices and to make modifications to their environment in order to handle activities of daily living and to function independently. Weak joints can be stabilized with devices such as ankle-foot orthoses (AFOs) and knee-AFOs, but walking may still require a lot of effort. Increasing activity will increase chances of recovery.

Ideally, effective treatment aims to resolve the underlying cause and restores the nerve root to normal function. Common conservative treatment approaches include physical therapy and chiropractic. A systematic review found moderate quality evidence that spinal manipulation is effective for the treatment of acute lumbar radiculopathy and cervical radiculopathy. Only low level evidence was found to support spinal manipulation for the treatment of chronic lumbar radiculopathies, and no evidence was found to exist for treatment of thoracic radiculopathy.

While conservative approaches for rehabilitation are ideal, some patients will not improve and surgery is still an option. Patients with large cervical disk bulges may be recommended for surgery, however most often conservative management will help the herniation regress naturally. Procedures such as foraminotomy, laminotomy, or discectomy may be considered by neurosurgeons and orthopedic surgeons.

The visual prognosis in optic nerve hypoplasia is quite variable. Occasionally, optic nerve hypoplasia may be compatible with near-normal vision; in other cases, one or both eyes may be functionally, or legally blind. Although most patients with only optic nerve involvement lead normally productive lives, those with accompanying endocrine dysfunction or other midline cerebral abnormalities are more at risk for on-going intellectual and other disabilities.

Entoptic phenomena (from Greek ἐντός "within" and ὀπτικός "visual") are visual effects whose source is within the eye itself. (Occasionally, these are called entopic phenomena, which is probably a typographical mistake.)

In Helmholtz's words; "Under suitable conditions light falling on the eye may render visible certain objects within the eye itself. These perceptions are called "entoptical"."

The procedure of spine shortening via vertebral osteotomy (SSVO) for TCS is a surgical technique that avoids the complication with revision tethering. In this research a lateral retropleural approach was used for SSVO in recurrent TCS in a 21-year-old female. The patient presented with progressive lower extremity weakness, bowel and bladder incontinence, and back pain in the setting of childhood repair of mylomeningocele and two previous detethering procedures. The research on performing SSVO in this patient allowed the scientists to conclude that SSVO via lateral retropleural approach is a good treatment for the recurrence of TCS. This procedure is minimally invasive compared to the posterior approach which gives the advantages of having direct access to the vertebral body and disc while avoiding the need to have an operation near the spinal cord but further research is still needed.

Entoptic images have a physical basis in the image cast upon the retina. Hence, they are different from optical illusions, which are perceptual effects that arise from interpretations of the image by the brain. Because entoptic images are caused by phenomena within the observer's own eye, they share one feature with optical illusions and hallucinations: the observer cannot share a direct and specific view of the phenomenon with others.

Helmholtz comments on phenomena which could be seen easily by some observers, but could not be seen at all by others. This variance is not surprising because the specific aspects of the eye that produce these images are unique to each individual. Because of the variation between individuals, and the inability for two observers to share a nearly identical stimulus, these phenomena are unlike most visual sensations. They are also unlike most optical illusions which are produced by viewing a common stimulus. Yet, there is enough commonality between the main entoptic phenomena that their physical origin is now well understood.

One area of treatment is managing people with major bleeding in a critical setting, like an emergency department. In these situations, the common treatment is transfusing a combination of red cells with one of the following options:

- Blood plasma

- Prothrombin complex concentrate, factor XIII, and fibrinogen

- Fibrinogen with tranexamic acid

The use of tranexamic acid is the only option that is currently supported by a large, randomized, controlled clinical trial, and is given to people with major bleeding after trauma. There are several possible risks to treating coagulopathies, such as transfusion-related acute lung injury, acute respiratory distress syndrome, multiple organ dysfunction syndrome, major hemorrhage, and venous thromboembolism.

If someone has coagulopathy, their health care provider may help them manage their symptoms with medications or replacement therapy. In replacement therapy, the reduced or absent clotting factors are replaced with proteins derived from human blood or created in the laboratory. This therapy may be given either to treat bleeding that has already begun or to prevent bleeding from occurring.