Vision Changes

If you experience a sudden change in vision - from your ability to focus to a full or partial loss of vision - talk to a doctor right away.

Not every vision change indicates an emergency, but immediate medical attention is always recommended.

Is this an emergency?

Urgent Symptoms

Flashes, Floaters, and Shadows

Occasional flashes and floaters are normal. However, a sudden heavy onset of flashes, floaters, or a curtain-like “shadow” in your field of vision should be considered a medical emergency.

Blurred Vision

Vision that suddenly becomes blurred could indicate one of many ocular conditions requiring immediate attention. On the other hand, gradual blurring could indicate a non-emergency such as cataracts.

Vision Loss in One Eye

Vision loss in one eye could be indicative of several conditions, including a stroke. You should speak to a physician about this change immediately.

Age, Lifestyle, and Other Risk Factors

If you have uncontrolled diabetes, are over the age of 40, or work in a profession that places you at risk of eye injuries, you may face a higher risk of experiencing a sudden change in vision. Pregnant women often experience blurred vision or double vision due to hormonal changes.

Why Vision Changes Occur

Retinal Detachment

The retina is the light-sensitive tissue on the back inner surface of the eye that transmits light to the brain via the optic nerve. When this tissue is disrupted, it can result in a sudden change of vision.

Intraocular Pressure

Vision that becomes slightly blurred or compromised by rainbow-like halos can indicate closed-angle glaucoma. This disease involves a sudden increase in intraocular pressure due to blocked drainage of the fluid behind the cornea. It is usually accompanied by headaches and nausea. Open-angle glaucoma has a much more gradual onset, with vision becoming compromised only after permanent damage has taken place.

Hormones, Aging, and Other Factors

Hormonal changes during pregnancy can interfere with the ability to focus, but subside following pregnancy. Meanwhile, vision naturally degrades with age, and can be further compromised by cataracts. Presbyopia (age-related farsightedness) can begin developing around age 40. Stress can sometimes spur changes in vision such as central serous retinopathy, the development of a blister beneath the retina.
Eye diseases are common and can go unnoticed for a long time—some have no symptoms at first. A comprehensive dilated eye exam by an optometrist or ophthalmologist (eye doctor) is necessary to find eye diseases in the early stages when treatment to prevent vision loss is most effective. Centers for Disease Control

Prevention through Eye Exams and a Healthy Lifestyle

Undergo Regular Eye Exams

The American Optometric Association (AOA) recommends that adults undergo an eye exam every two years and begin having checkups annually at age 60.

Keep Diabetes under Control

Diabetics run an increased risk of several diseases that can result in a sudden vision change or blindness. If you have been diagnosed with diabetes, follow your doctor’s guidelines for managing the condition and make sure to undergo regular exams.

Diet, Exercise, Etc.

Simple measures such as eating a diet rich in antioxidants and omega-3 fatty acids, light exercise, abstaining from tobacco, and protecting your eyes from UV rays can help reduce your risk of macular degeneration, cataracts, and other conditions.

Assessing Your Ocular Health

Time Pain Level Results
20-30 minutes None Usually immediate

Your doctor will want to know which medications you take, any eye conditions with which you have been previously diagnosed, and any family history of conditions such as diabetes, heart disease, glaucoma, and macular degeneration. Your eye exam may also include a series of tests, including:

  1. Following a slow-moving object (such as a pen) with your eyes to assess the eye muscles.
  2. Reading letters on a chart across the room.
  3. Measuring how your cornea refracts light.
  4. Assessing your field of vision and color perception.
  5. Assessment of the eyelids, cornea, lens, and iris using a slit lamp.

eye examYour doctor will examine the inner structures of your eyes to provide an accurate diagnosis.

Retinal Exam and Glaucoma Screening

Your doctor may dilate your eyes in order to achieve a clear view of the retina and look for any abnormalities. He or she will also use special tools to measure your intraocular pressure (IOP). Abnormally high IOP may indicate glaucoma.

Prompt Attention is Essential

Laser Retina Treatment

Advanced laser treatment can repair retinal tears and other issues that compromise the retina. Pneumatic retinopexy is an alternative treatment in which a gas bubble is placed in the eye to hold the retina in its proper position as it heals.


If vision loss is attributed to glaucoma, your doctor may be able to recommend treatments to preserve remaining sight. Closed-angle glaucoma sufferers are given drugs to reduce IOP, restore fluid drainage, and reduce nausea.


If you are diagnosed with glaucoma, surgery may be necessary to permanently improve drainage and regulate IOP. Surgery can also help control macular degeneration.


For less urgent conditions, such as cataracts, you should continue undergoing regular examinations. Surgery or other treatments may eventually become necessary in order to maintain focus.

Prevention Is the Key

Vision changes often happen without warning. If your vision has suddenly changed, or if you are not undergoing eye exams regularly, contact a doctor today.

Sheth Horsley Eye Center

The ophthalmologists at Sheth Horsley Eye Center have been serving the community's eye care needs for over 50 years. Our doctors are members of various prestigious organizations, including:

  • American Academy of Ophthalmology
  • International Society of Refractive Surgery
  • American Society of Cataract and Refractive Surgery
  • American Association of Physicians of Indian Origin

To schedule a consultation at one of our three office locations, request an appointment online or call us at (781) 979-0960.

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