Codes and Frequencies
GLAUCOMANOWC indicates whether the person now has chronic glaucoma. This variable is created with supplemental programming by the IPUMS NHIS staff from the pre-1997 condition records. For general information about IHIS variables (such as GLAUCOMANOWC) created from the pre-1997 condition records, see the User Note on Condition Records and Condition Variables.
Defining Glaucoma Records and Identifying Persons with Glaucoma
For all available years, persons who were asked a direct question about having glaucoma and who have a chronic glaucoma condition record are given a "Yes" code for GLAUCOMANOWC. Persons who were asked a direct question about having glaucoma but do not have a chronic glaucoma record are given a code of "No." Persons who were not asked a direct question about glaucoma, or for whom it is unknown whether they were asked such a question, are given a code of "NIU" (not in universe), regardless of whether they have a chronic glaucoma record.
For 1971 and for 1977 to 1981, chronic glaucoma records were defined as those condition records with a code of "122" ("Glaucoma, all forms") in the variable DIAGR1 in the original NHIS public use files. This condition code value comes from NCHS's Diagnostic Recode #1: Diseases, Injuries, and Impairments not from the International Classification of Diseases (ICD) codes. Additionally, to be considered "chronic," glaucoma records must have a code of "1" ("Chronic") in the variable CACODE in the original NHIS public use files.
For 1982 to 1996, chronic glaucoma records were defined as those condition records with a code of "242" ("Glaucoma") in the variable C1CONDRC in the original NHIS public use files. This condition code value comes from NCHS's Diagnostic Recode C: Chronic Conditions and Impairments.
For 1971 and 1977, GLAUCOMANOWC should be weighted with PERWEIGHT.
For 1978 to 1981, GLAUCOMANOWC should be weighted with CONDWT4.
For 1982 to 1996, GLAUCOMANOWC should be weighted with CONDWT2.
Related Glaucoma Variables
The nearest equivalent of GLAUCOMANOWC available after 1996 is GLAUCOMAEV (Ever told had glaucoma). However, researchers should use caution when comparing prevalence estimates derived from these two variables, as both the manner of collecting information about glaucoma and the reference period differ greatly between the two. GLAUCOMANOWC was created by recoding condition records that were generated in response to several different survey questions about health problems underlying disability, sick days, or contacts with health care practitioners. GLAUCOMANOW, by contrast, is based on a direct question about whether the person had glaucoma.
As with all of the person-level condition variables created by IHIS from condition records prior to 1997, the universe for GLAUCOMANOWC is substantially different for 1978 forward than it is for years prior to 1978. Beginning in 1978, only persons living in 1/6 of households, rather than all persons, were asked a direct question about currently having glaucoma. There is also a minor universe change between the sets of years 1978-1981 and 1982-1996. These changes require that different weight variables be used depending on which years of data are analyzed. See the "Description" tab for details.
Additionally, there is a change in the way "Yes" responses are coded over time. See the User Note on Condition Records and Condition Variables for details about the composite coding scheme employed by IHIS.
- 1971; 1977: All persons.
- 1978-1981: Persons living in 1/6 of households (who received Condition List 4).
- 1982-1996: Persons living in 1/6 of households (who received Condition List 2).
- 1971, 1977-1996