Visual Function

VEHSS reports the prevalence of Visual Function indicators as the proportion or persons or patients in each dataset with each visual function category or response value, based on survey-self reported vision or function, objectively measured visual acuity, or diagnosed low vision.

Measured Visual Acuity

VEHSS includes measured visual acuity from published examination studies, examination surveys and EHR registries.  Further details of examination-based indicators from surveys and published sources are available in the following technical documentation:

VEHSS Survey Analysis Plan CDC pdf icon[PDF – 480 KB]external icon

VEHSS Claims and Registry Data Analysis Plan CDC pdf icon[PDF – 580 KB]external icon

Literature Review of Examination-Based Studies CDC pdf icon[PDF – 1.4 MB]external icon

Diagnosis Code Indicators

The VEHSS system uses diagnosis codes to identify vision and eye disorders in all administrative claims and electronic medical registry data. Diagnosis codes are based on the International Classification of Diseases (ICD) system. All ICD-9 and ICD-10 codes related to vision, the eye, and ocular adnexa are categorized in a two-level categorization system using mutually exclusive categories and sub-groups to provide more efficient estimates of key vision and eye health outcomes.

VEHSS Diagnosis Code Categories and Crosswalk CDC pdf icon[PDF – 2.1 MB]external icon This report includes the ICD-9 and ICD-10 codes mapped to each category and subgroup. Updated spreadsheet versions of this crosswalk are available upon request.

VEHSS Claims and Registry Data Analysis Plan CDC pdf icon[PDF – 580 KB]external icon This report details VEHSS’ approach to utilizing administrative claims and registry data to create systematic single-source estimates.

Other Visual Disturbances includes indicators representing both Visual Function and Eye Health Conditions. VEHSS includes indicators of Other Visual Disturbances from claims databases and IRIS Registry.

Diagnosed or Treated

Blindness or Low Vision includes diagnosis codes indicating low vision or blindness in two types of data sources:

  • Diagnosed prevalence: IRIS Registry indicates Diagnosed conditions that exists in the patient’s medical record.
  • Treated prevalence: Administrative claims databases indicate Treated conditions for which a diagnosis code was included anywhere on a submitted bill.

Diagnosed or Treated Blindness or Low Vision is indicated by a patient having one or more diagnosis codes indicating one or more of the blindness or low vision subgroups listed below.

Blindness or Low Vision Subgroups
Subgroup Indicated conditions
Unqualified visual loss, both eyes Unqualified vision loss, both eyes includes a diagnosis code indicating unqualified visual loss in both eyes.
Unqualified vision loss in one eye, or unspecified visual loss Unqualified vision loss in one eye or unspecified vision loss includes diagnosis codes indicating unqualified vision loss in one eye, unspecified visual loss, or problems with sight.
Low vision or blindness, one eye Low vision or blindness in one eye includes diagnosis codes indicating low vision or blindness in one eye, normal vision in the other eye.
Blindness one eye, low vision other eye Blindness in one eye, low vision in other eye includes diagnosis codes indicating blindness in one eye, low vision in other eye.
Low vision, both eyes Low vision, both eyes includes diagnosis codes indicating low vision in both eyes.
Blindness, both eyes, including legal blindness Blindness, both eyes, including legal blindness includes diagnosis codes indicating blindness in both eyes, legal blindness, or cortical blindness.

Full lists of ICD9 and ICD10 codes: VEHSS diagnosis codes reportexternal icon

Diagnosed or Treated Blindness or Low Vision Indicator Data Sources
Dataset Years analyzed Reporting type
IRIS 2016, 2017, 2018 Diagnosed
Medicaid MAX 2013, 2014 Treated
Medicare 100% FFS claims 2014, 2015, 2016, 2017 Treated
Managed Vision Care 2016 Treated
MarketScan commercial insurance 2016 Treated

VEHSS includes indicators of Far-Distance Visual Function from self-report surveys.

Self-reported

Self-reported Far-Distance Visual Function indicates the respondent replied that they have difficulty with tasks that require good distance vision.

Self-reported Far-Distance Visual Function
Dataset Description Question Text Variable name(s) Years available Years analyzed Response options
NHIS Percentage of adults who even when wearing glasses or contact lenses find it (not at all, only a little, somewhat, or very) difficult to drive during daytime in familiar places (NHIS Adult Module) Even when wearing glasses or contact lenses, because of your eyesight, how difficult is it for you…to drive during daytime in familiar places? DRV,
AVDFDRV,
AVDF_DRV
1999,
2002,
2008,
2016,
2017
2016, 2017 0 Not at all difficult
1 Only a little difficult
2 Somewhat difficult
3 Very difficult
4 Can’t do at all (because of eyesight; 2008)
6 Do not do this activity (for other reasons; 2008)
7 Refused
8 Not ascertained (2008)
9 Don’t know
NHIS Percentage of adults who wear eyeglasses or contact lenses to drive, read road and street signs, watch TV, or see things in the distance (NHIS Adult Module) Do you wear eyeglasses or contact lenses to drive, read road and street signs, watch TV, or see things in the distance? VIMDRIVE 2016, 2017 2016, 2017 1 Yes
2 No
7 Refused
8 Not ascertained
9 Don’t know
NHIS Percentage of children who wear eyeglasses or contact lenses to read road and street signs, see the blackboard, play sports, watch TV, or see things in the distance (NHIS Child Module) Does [fill: SC name] wear eyeglasses or contact lenses to read road and street signs, see the blackboard, play sports, watch TV, or see things in the distance? CVISDIST 2008, 2016, 2017 2016, 2017 1 Yes
2 No
7 Refused
9 Don’t know
NHIS Percentage of children who can read the board from the back of the classroom (NHIS Child Module) Can [fill1: S.C. name] read the board from the back of the classroom? CVISRD 2008, 2016, 2017 2016, 2017 1 Yes
2 No
7 Refused
9 Don’t know

VEHSS includes indicators of Functional Difficulty from self-report surveys.

Self-reported

Self-reported Functional Difficulty indicates the respondent replied that they have difficulty completing functional tasks due to vision.

Self-reported Functional Difficulty
Dataset Description Question text Variable name(s) Years available Years analyzed Response options
NHIS Percentage of adults who even when wearing glasses or contact lenses find it (not at all, only a little, somewhat, or very) difficult to find something on a crowded shelf (NHIS Adult Module) Even when wearing glasses or contact lenses, because of your eyesight, how difficult is it for you…to find something on a crowded shelf? CRD, AVDFCRD, AVDF_CRD 1999, 2002, 2008, 2016, 2017 2016, 2017 0 Not at all difficult
1 Only a little difficult
2 Somewhat difficult
3 Very difficult
4 Can’t do at all (because of eyesight; 2008)
6 Do not do this activity (for other reasons; 2008)
7 Refused
8 Not ascertained (2008)
9 Don’t know

Measured Visual Acuity refers to measured acuity in the better-seeing eye using eye charts, autorefractors, and other methods. Measured Visual Acuity includes the following types:

  • Best corrected: Measured with optimal correction.
  • Presenting: Measured using a patient or respondents’ glasses or contacts they were wearing at the time of the exam.
  • Uncorrected refractive error: Calculated as patients with ≤20/50 presenting, but improve to ≤20/40 best corrected.

NHANES, IRIS Registry, and published examination studies include measured visual acuity.

VEHSS classifies each type of visual acuity based on the following scale:

Visual Acuity Categories, best corrected or presenting
Description Definition
Normal Vision 20/12.5 – 20/25 (better-seeing eye)
Any Vision Loss ≤20/32 (better-seeing eye)
Visual Impairment 20/32 – 20/160 (better-seeing eye)
US Defined Blindness ≤20/200 (better-seeing eye)
World Health Organization (WHO) Defined Blindness ≤20/400 (better-seeing eye)
Monocular Vision Loss ≤20/70 in worse eye, mild or normal in better-seeing eye
Uncorrected Refractive Error ≤20/50 (presenting in better-seeing eye, improving to >20/40 with correction)
Missing Acuity No acuity measure classified above
Measured Visual Acuity Indicators
Dataset Description Variables Years available Years analyzed Response options
IRIS Registry Best-corrected visual acuity Best corrected acuity 2014-2016 2016 Normal Vision
Any Vision Loss
Visual Impairment
US-defined Blindness
Monocular Vision Loss
NHANES Best-corrected visual acuity VIDROVA – Right visual acuity, w/
obj. refraction;
1999-2008 1999-2008 Normal Vision
Any Vision Loss
Visual Impairment
US-defined Blindness
Monocular Vision Loss
VIDLOVA – Left visual acuity, w/
obj. refraction
VIQ017-Blind in both eyes*
NHANES Presenting visual acuity VIDRVA – Right visual acuity, presenting; 1999-2008 1999-2008 Presenting with normal vision
Presenting with any vision loss
Presenting with visual impairment
Presenting with US-defined blindness
Presenting with monocular vision loss
VIDLVA – Left visual acuity,
presenting
VIQ017-Blind in both eyes*
NHANES Uncorrected Refractive Error (URE) VIDRVA – Right visual acuity, presenting; 1999-2008 1999-2008 Uncorrected Refractive Error (URE)
VIDLVA – Left visual acuity,
presenting;
VIDROVA – Right visual acuity, w/
obj. refraction;
VIDLOVA – Left visual acuity, w/
obj. refraction

VEHSS uses data from the following published estimates of blindness and low vision to create multi-source prevalence estimates. Please see the VEHSS literature review for details and other published studies.

Population-based Examination Studies
Study Years Location Citation
Baltimore Pediatric Eye Study (BPEDS) 2003-2007 Maryland Friedman D, Repka M, Katz J, et al. Prevalence of Decreased Visual Acuity among Preschool Aged Children in an American Urban Population: The Baltimore Pediatric Eye Disease Study, Methods and Results. Ophthalmology. 2008:115(10):1786-1795.
Chinese American Eye Study (CHES) 2010-2013 California Varma R, Kim JS, Burkemper BS, et al. Prevalence and Causes of Visual Impairment and Blindness in Chinese American Adults: The Chinese American Eye Study. JAMA Ophthalmol.2016;134(7):785–793.
Eye Diseases Prevalence Research Group (EDPRG) 1990-2001 National The Eye Diseases Prevalence Research Group. Causes and prevalence of visual impairment among adults in the United States. Arch Ophthalmol. 2004;122:477–485.
Los Angeles Latino Eye Study (LALES) 2000-2003 California Varma R, Ying-Lai M, Klein R, Azen SP; G. Los Angeles Latino Eye Study. Prevalence and risk indicators of visual impairment and blindness in Latinos: The Los Angeles Latino Eye Study. Ophthalmology. 2004;111(6):1132–1140.
Multi-ethnic Study of Atherosclerosis (MESA) 2002-2004 National Fisher DE, Shrager S, Shea SJ, et al. Visual Impairment in White, Chinese, Black, and Hispanic Participants from the Multi-Ethnic Study of Atherosclerosis Cohort. Ophthalmic Epidemiol. 2015;22(5):321–332.
Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) 1980-2007 Wisconsin Klein R, Lee KE, Knudtson MD, Gangon RE, Klein BE. Changes in Visual Impairment Prevalence by Period of Diagnosis of Diabetes: The Wisconsin Epidemiologic Study of Diabetic Retinopathy. Ophthalmology. 2009;116(10):1937–1942.

VEHSS includes indicators of Near-Distance Visual Function from self-report surveys.

Self-reported

Self-reported Near-Distance Visual Function indicates the respondent replied that they have difficulty with tasks that require good near distance vision.

Self-reported Near-Distance Visual Function
Dataset Description Question text Variable name(s) Years available Years analyzed Response options
NHIS Percentage of adults who wear eyeglasses or contact lenses to read books or newspaper, write, or other things that require them to see well up close (NHIS Adult Module) Do you wear eyeglasses or contact lenses to read books or newspapers, write, or do other things that require you to see well up close, such as cooking, sewing or fixing things? VIMREAD 2008, 2016, 2017 2016, 2017 1 Yes
2 No
7 Refused
9 Don’t know
NHIS Percentage of adults who even when wearing glasses or contact lenses find it (not at all, only a little, somewhat, or very) difficult to read ordinary print in newspapers (NHIS Adult Module) Even when wearing glasses or contact lenses, because of your eyesight, how difficult is it for you…to read ordinary print in newspapers? NWS, AVDF_NWS 1999, 2002, 2008, 2016, 2017 2016, 2017 0 Not at all difficult
1 Only a little difficult
2 Somewhat difficult
3 Very difficult
4 Can’t do at all because of eyesight
6 Do not do this activity for other reasons
7 Refused
9 Don’t know
NHIS Percentage of adults who when wearing glasses or contact lenses find it (not at all, only a little, somewhat, or very) difficult to do work or hobbies that require them to see well up close (NHIS Adult Module) Even when wearing glasses or contact lenses, because of your eyesight, how difficult is it for you…to do work or hobbies that require you to see well up close such as cooking, sewing, fixing things around the house, or using hand tools? CLS, AVDF_CLS 1999, 2002, 2008, 2016, 2017 2016, 2017 0 Not at all difficult
1 Only a little difficult
2 Somewhat difficult
3 Very difficult
4 Can’t do at all because of eyesight
6 Do not do this activity for other reasons
7 Refused
9 Don’t know
NHIS Percentage of children who wear eyeglasses or contact lenses to read books, write, play hand-held games, or do other things that require them to see well up close (NHIS Child Module) Does [fill: SC name] wear eyeglasses or contact lenses to read books, write, play hand-held games, or do other things that require [fill: her/him] to see well up close? CVISREAD 2008, 2016, 2017 2016, 2017 1 Yes
2 No
7 Refused
9 Don’t know

VEHSS includes indicators of Night or Low Light Vision from self-report surveys.

Self-reported

Self-reported Night or Low Light Vision indicates the respondent replied that they have difficulty with tasks that require good night vision.

Dataset Description Question text Variable name(s) Years available Years analyzed Response options
Self-reported Night or Low Light Vision
NHIS Percentage of adults who even when wearing glasses or contact lenses find it (not at all, only a little, somewhat, or very) difficult to go down steps, stairs, or curbs in dim light or at night (NHIS Adult Module) Even when wearing glasses or contact lenses, because of your eyesight, how difficult is it for you…to go down steps, stairs or curbs in dim light or at night? NIT, AVDFNIT, AVDF_NIT 1999, 2002, 2008, 2016, 2017 2016, 2017 0 Not at all difficult
1 Only a little difficult
2 Somewhat difficult
3 Very difficult
4 Can’t do at all (because of eyesight; 2008)
6 Do not do this activity (for other reasons; 2008)
7 Refused
8 Not ascertained (2008)
9 Don’t know

Other Visual Disturbances includes indicators representing both Visual Function and Eye Health Conditions. VEHSS includes indicators of Other Visual Disturbances from claims databases and IRIS Registry.

Diagnosed or Treated

Other visual disturbances includes diagnosis codes indicating visual field defects, color vision deficiencies, night blindness, and other or unspecified visual disturbances.

  • Diagnosed prevalence: IRIS Registry indicates Diagnosed conditions that exists in the patient’s medical record.
  • Treated prevalence: Administrative claims databases indicate Treated conditions for which a diagnosis code was included anywhere on a submitted bill.

Diagnosed or Treated other visual disturbances includes a patient having one or more diagnosis codes indicating one or more of the other visual disturbances subgroups listed below.

Subgroup Indicated conditions
Other Visual Disturbances Subgroups
Visual field defect Visual field defect includes diagnosis codes indicating defects of the visual field, including scotoma, sector or arcuate defects, localized visual field defects, homonymous bilateral field defects or contraction of the visual field.
Color blindness Color blindness included diagnosis codes indicating color vision deficiencies.
Night blindness Night blindness includes diagnosis codes indicating night blindness, abnormal dark adaptation and glare sensitivity.
Other/unspecified visual disturbances Other/unspecified visual disturbances includes other disturbances or defects of sight including subjective visual disturbances, diplopia, other and unspecified disorders of binocular vision, and vision sensitivity deficiencies.

Full lists of ICD9 and ICD10 codes: VEHSS diagnosis codes reportexternal icon

Other Visual Disturbances Indicator Data Sources
Dataset Years analyzed Measure type
IRIS 2016, 2017, 2018 Diagnosed
Medicare 100% FFS claims 2014, 2015, 2016, 2017 Treated
Managed Vision Care 2016 Treated
Medicaid MAX 2013, 2014 Treated
MarketScan commercial 2016 Treated

Self-Assessed Blind or Difficulty Seeing includes self-response survey questions indicating blindness, difficulty seeing, or vision problems.

Survey Description Question text Variable name(s) Years available Years analyzed Response options
Self-reported Blind or Difficulty Seeing
ACS Percentage of people who are blind or have serious difficulty seeing even when wearing glasses Is this person blind or does he/she have serious difficulty seeing even when wearing glasses? DIFFEYE 2008-2016 2014-2015 1 Yes
2 No
0 Not applicable
NSCH Percentage of children who were ever told by doctor that they had a vision problem that cannot be corrected with glasses or contact lenses Does this child have any of the following? Blindness or problems with seeing, even when wearing glasses BLINDNESS 2016, 2017 2016, 2017 1 Yes
2 No
BRFSS Percentage of people who are blind or have serious difficulty seeing even when wearing glasses Are you blind or do you have serious difficulty seeing, even when wearing glasses? BLIND 2013-2017 2013-2017 1 Yes
2 No
7 Don’t know / Not sure
9 Refused
NHANES Percentage of people blind in both eyes “{Are you/Is SP} blind in both eyes?
Next I have general questions about (your/SP’s) vision. With both eyes open, can (you/he/she) see light?”
VIQ017 2005, 2008 2005, 2008 1 Yes
2 No
7 Don’t know / Not sure
9 Refused
NHIS Percentage of adults who have trouble seeing even when wearing glasses or contact lenses (NHIS Adult Module) Do you have any trouble seeing, even when wearing glasses or contact lenses? AVISION 1999-2017 2014-2015 1 Yes
2 No
7 Refused
8 Not ascertained
9 Don’t know
NHIS Percentage of children have any trouble seeing even when wearing glasses or contact lenses (NHIS Child Module) Does [child] have any trouble seeing [fill2:], even when wearing glasses or contact lenses? CVISION 1999-2017 2014-2015 1 Yes
2 No
7 Refused
8 Not ascertained
9 Don’t know
NHIS Percentage of people who have (no, some, a lot) difficulty seeing even when wearing glasses (NHIS Functioning and Disability Module) Do you have difficulty seeing, even when wearing glasses? VIS_SS 2011-2017 2014-2015 1 No difficulty
2 Some difficulty
3 A lot of difficulty
4 Cannot do at all/unable to do
7 Refused
9 Don’t know
NHIS Percentage of adults who are blind or unable to see at all (NHIS Adult Module) Are you blind or unable to see at all? ABLIND 1999-2017 2014-2015 1 Yes
2 No
7 Refused
9 Don’t know
NHIS Percentage of children who are blind or unable to see at all (NHIS Child Module) Is [child] blind or unable to see at all? CBLIND 1999-2017 2014-2015 1 Yes
2 No
7 Refused
8 Not ascertained
9 Don’t know

VEHSS includes indicators of Visual Field from self-report surveys.

Self-reported

Self-reported Far-Distance Visual Function indicates the respondent replied that they have difficulty with tasks that require good peripheral vision.

Dataset Description Question text Variable name(s) Years available Years analyzed Response options
Self-reported Far-Distance Visual Function
NHIS Percentage of adults who even when wearing glasses or contact lenses find it (not at all, only a little, somewhat, or very) difficult to notice objects off to the side while you are walking along (NHIS Adult Module) Even when wearing glasses or contact lenses, because of your eyesight, how difficult is it for you…to notice objects off to the side while you are walking along? PER, AVDFPER, AVDF_PER 1999, 2002, 2008,
2016,
2017
2016, 2017 0 Not at all difficult
1 Only a little difficult
2 Somewhat difficult
3 Very difficult
4 Can’t do at all (because of eyesight; 2008)
6 Do not do this activity (for other reasons; 2008)
7 Refused
8 Not ascertained (2008)
9 Don’t know