Yes, 20/70 vision is worse than 20/40 vision.
A visual acuity of 20/70 represents more severe visual impairment than 20/40, meaning the person must be at 20 feet to see what someone with normal vision can see at 70 feet, compared to 40 feet for 20/40 vision.
Understanding the Visual Acuity Scale
The Snellen visual acuity notation works as a fraction where:
- The first number (always 20 in standard testing) = the testing distance in feet
- The second number = the distance at which a person with normal vision could read the same line
The larger the bottom number, the worse the vision. Therefore:
- 20/40 means moderate visual impairment
- 20/70 means more severe visual impairment
- 20/200 or worse defines legal blindness
Clinical Significance of These Thresholds
According to the USPSTF guidelines, visual acuity worse than 20/40 defines the threshold for visual impairment 1. This classification is clinically meaningful because:
- 20/40 is the cutoff for unrestricted driver's licenses in many states 1
- Visual impairment (defined as worse than 20/40 but better than 20/200) affects approximately 2.91 million Americans aged 60+ 1
- Impaired visual acuity is consistently associated with decreased quality of life, reduced ability to perform activities of daily living, inability to drive safely, and increased risk of falls and injuries 1
Practical Implications
Since 20/70 falls within the "impaired visual acuity" range (worse than 20/40 but better than 20/200), a person with 20/70 vision would likely:
- Not qualify for an unrestricted driver's license in most jurisdictions
- Experience more difficulty with daily activities than someone with 20/40 vision
- Have higher mortality risk, particularly from non-cardiovascular, non-cancer causes 2
The progression from 20/40 to 20/70 represents clinically meaningful deterioration that warrants ophthalmologic evaluation to identify and treat correctable causes such as refractive errors, cataracts, or macular degeneration 1.