Vision is the most important and must have sensory feature for a human beings. Without vision we can't able to do our daily routines by ourself. Vision is the best thing that everyone have. Unfortunately many diseases are involved in the interruption of normal of eyesight. Such diseases needs proper treatment and care to restore the vision. This article will provide the causes of sudden loss of vision.
Sudden loss of Vision:
Painless:
1. CRAO(Central Retinal Artery Occlusion)
2. CRVO( Central Retinal Vein Occlusion)
3. Retinal detachment
4. Optic Neuritis
5. Vitreous Haemorrhage
6. Central Serous Retinopathy
7. Methyl Alcohol Amblyopia
Painful:
8.Acute Iridocyclitis
9. Acute Congestive Glucoma
10. Injuries to eyeball/ Trauma
1) Central Retinal Artery Occlusion (CRAO):
CRAO is more common among hypertensive & other cardiovascular disease patients. Common causes are,
- Emboli (cholesterol, calcium & fibrin)
- Atherosclerosis
- Obliteration of retinal vessels
- Angiospasms
- Increased intra occular pressure
- Thrombophilic disorders
It is more common in males than females and mostly unilateral. It present as central retinal artery occlusion - 60%, branch artery occlusion - 35%, cilioretinal artery occlusion - 5%.
Symptoms appears as sudden painless loss of vision with previous history of transient loss of vision. RAPD (Relative Afferent Pupillary Defect) is positive.
Management includes,
- Lowering of intraocular pressure
- fibrinolytic drugs
- Vasodilators
- Inhalation of mixture of 5% CO2 and 95% oxygen to reduce angiospasm.
- Laser photodisruption
- treatment of the cause.
2) Central Retinal Vein Occlusion (CRVO):
It is more common than retinal artery occlusion and affects older patients. The main causes are,
- pressure on vein due to atherosclerotic artery.
- Hyperviscosity of blood
- Diabetes and hypertension
- Periphlebitis retinae
- raised intraocular pressure
- tumours, cellulitis etc.,
It is divided into ischaemic and non - ischaemic types. It should be differentiated from diabetic retinopathy and Ocular ischaemic syndrome.
Treatment includes,
- Intraviteral anti VEHFs
- Triamcinolone
- Grid laser for persistant CME
- treatment of the cause ( hypertension, diabetes etc.,)
- Observation and monitoring.
3) Retinal detachment:
It is the separation of neurosensory retinal layers from pigmentary epithelium.
It occurs with myopia, aphakia and pseudophakia, retinal degenerations, vitreous detachment and trauma.
Symptoms of detached retina are,
- localised field of vision loss
- Appearance of dark cloud infront of eye
- Sudden loss of vision without any pain.
Treatment is done by, sealing of retinal breaks, drainage of subretinal fluids and maintaining the chorioretinal apposition.
4) Optic Neuritis:
It is the inflammatory and demyelinating disease of the optic nerve.
It is due to many cases infections, autoimmune disorders, hereditary and idiopathic. It is divided into three types, papillitis, Neuroretinitis and Retrobulbar Neuritis.
Symptoms of optic neuritis are,
- Visual loss
- Dark adaptation is decreased
- defective colour vision
- Visual obscuration in bright light
- impaired depth perception
It should be differentiated from papilloedema, ischaemic optic neuropathy, malingering and psuedopapillitis.
Treatment includes, treating the underlying cause and corticosteroid therapy ( prednisolone and methylprednisolone).
5) Vitreous Haemorrhage:
Vitreous haemorrhage occurs from the vessels of retina and it present as intragel or preretinal haemorrhage. The intra viteral haemorrhage my occurs in anterior, middle, posterior or entire vitreous humour.
Common causes are,
- Retinal tear, RD and PVD
- Hypertensive retinopathy, CRVO
- Diabetic retinopathy
- Trauma
- chorioretinitis and eale's disease
- bleeding disorders
Symptoms includes appearance of floaters and painless vision loss.
Depending upon the position of haemorrhage,is labeled as, anterior,mid, posterior and total vitreous haemorrhage.
Vitreous haemorrhage may be completely absorbed, organized into a yellowish white debris, liquefaction and leads to vitreous detachment.
Treatment includes consecutive therapy, treating the cause and vitrectomy.
6) Central Serous Retinopathy:
It is the spontaneous serous detachment of retina, especially in macular region. It occurs more in males and occurs with high steroid intake, stress, pregnancy and hypertension.
Patients presents with, acute painless vision loss. It should be differentiated from optic pits, serous detachment, choroidal vasculopathy and PED.
Treatment is the conservative management like discontinuation of steroids and life style changes,laser photocoagulation, anti VEGF and photodynamic therapy.
7) Methyl Alcohol Amblyopia:
It causes permanent blindness due to optic atrophy.
It occurs due to intake of methylated spirit wood alcohol and fortified beverages. Sometimes,it may be absorbed from skin and inhaled as fumes.
Is present as vomiting, headache, dizziness, abdominal pain, delirium,stupor & death. Formaldehyde odour in breath or sweat is the key for diagnosis.
Treatment includes,
- Gastric lavage
- Alkali administration
- Ethyl alcohol
- conservative therapy
Prognosis is poor and death occurs due to poisoning, blindness occurs for those who survive.
8) Acute Iridocyclitis:
It is the inflammation of the uveal tissue (iris and ciliary body) . It is due to infections, allergy, toxins, systemic diseases, trauma and idiopathic.
Patients usually present as pain, redness, photophobia and blepharospasm, lacrimation and defective vision.
It's complications are cataract,Glucoma, choroiditis, papillitis,phthisis bulbi and other retinal complications. It must be differentiated from acute red eye.
Treatment includes cycloplegic drugs, antibiotics corticosteroids,NSAIDS, hot fomentation,dark goggles and specific treatment of the cause.
9) Acute primary angle glaucoma:
It is an acute rise in intraocular pressure (IOP), occurs due to pupillary block leading to sudden closure of the angle.
Symptoms includes pain, nausea, vomiting, rapid impairment of vision, redness, photophobia, lacrimation and past history.
Management includes,
a) immediate therapy to lower IOP
- hyperostotics agents
- carbonic anhydrase inhibitors
- topical anti Glucoma drugs
- analgesics and antiemetics
- gonioscopy
- topical steroids
b) Definite therapy:
- laser peripheral iridotomy (LPI)
- filtration surgery
- lens extraction
c) Prophylatic treatment
d) long term surveillance and monitoring.
10) Injuries to eyeball:
Due to rapid industrialization,the incidence of injury is more common. Eyes are also a victim of any type of injuries or trauma. The injuries may be due to mechanical, chemical, radiational, electrical and thermal causes.
Mechanical injuries causes open globe or closed globe injuries. Removal of foreign body and reconstructive therapy can recover the normal physiological mechanisms.
The injuries may various from small repute or laceration to blunt open injuries. It can cause permanent blindness in many cases.
Apart from these ten major causes of blindness,other many chronic conditions of the eye also leads to complete blindness in later stages. Adequate measures and treatment should be done immediately to prevent the blindness.
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