Blurred vision refers to a lack of sharpness of vision resulting in the inability to see fine detail.Blurred vision may result from abnormalities present at birth such as near- or farsightedness that require corrective lenses (glasses) or it may signal the presence of eye disease. Blurred vision can also be a symptom of numerous conditions that do not directly involve the eye, such as migraine or stroke. A number of medications may also lead to temporary blurring of vision as a side effect.
What is the patient complaining of?
- Blurred vision - a single image that is seen indistinctly. Is this at distance, near or both?
- Decrease in peripheral vision - the patient may describe bumping into things or frequent scrapes when parking the car.
- Alteration of a clear image, eg micropsia/macropsia (image appears smaller or bigger) or metamorphopsia (distorted image).
- Interference with a clear image (eg floaters, flashes of light - photopsia).
- Diplopia - monocular (the double vision remains when the uninvolved eye is occluded); binocular (the vision returns to normal on covering one eye), horizontal, vertical, oblique.
- Other disturbances of vision, eg iridescent vision (haloes, rainbows), dark adaptation problems or night blindness (nyctalopia), colour vision abnormalities.
History of the presenting complaint
- Is it unilateral or bilateral?
- Was it sudden or gradual in onset? If sudden, what was the patient doing at the time; what have they done recently that may have affected the eyes, eg DIY, trauma? If gradual, over what period of time?
- Has this happened before? When, and what, happened? Has it been diagnosed?
- Are there any associated factors? Examples include any of the other visual phenomena described above, pain (distinguish between ocular pain and pain in the head), associated ocular complaints (eg red eye, discharge, abnormal appearances) or systemic complaints (eg headache, other neurological problems, generalised malaise).