Foreign Bodies

The ICD9 coding system describes diseases, signs and symptoms, injuries, poisonings, procedures and screening codes. Disease or symptom codes consist of a three-digit number (termed a ‘category’) followed, in most cases, by one or two additional specifying digits. For example, the three-digit code ‘427’ specifies cardiac arrhythmias and further digits are added to specify the type of arrhythmias, such as ‘AF’ (427.31). In most cases, physicians are required to specify codes to the fourth or fifth digit to bill the patient's insurance, although some diseases lack further specification (e.g. 042, human immunodeficiency virus). Some diseases of common etiologies cover multiple ICD9 categories based on acute and chronic effects, the anatomical areas affected or the disease severity and associated other events. ICD9 categories are further grouped hierarchically into sections and chapters.
Since the ICD9 terminology was designed primarily for billing and administrative functions, we developed custom ‘case groups’ of ICD9 codes to better allow for large-scale genomic research involving ICD9 codes. In general, we used the existing three-digit categories as a guide in designing our case groups. We performed one of several functions on the original ICD9 terminology: (i) we combined three-digit codes that represented common etiologies [e.g. creating a single ‘tuberculosis’ code group from 010 to 018 (primary tuberculosis), 137 (late effects of tuberculosis) and 647.3 (tuberculosis complicating the peripartum period)]; (ii) for clinically distinct phenotypes that are combined in a single three-digit code, we divided the existing ICD9 classification (by adding a fourth digit), such as Type 1 and Type 2 diabetes (both part of code ICD9 category 250); and (iii) we marked as ‘ignorable’ other ICD9 codes that were unlikely to be useful in a genetic context, such as contamination with foreign objects, non-specific signs and symptoms [e.g. 790.6 (other abnormal blood chemistry)], non-specific laboratory results, elective abortions and iatrogenic complications of medical care. There were 395 fully specified diagnosis-related ICD9 codes ignored from the analysis. When combining ICD9 codes from disparate parts of the code groupings (e.g. tuberculosis above contains codes in the ICD9 chapters ‘infectious and parasitic diseases’ and ‘complications of pregnancy, childbirth and the puerperium’), we chose the case group number most closely related to the etiology of the disease (e.g. we grouped all tuberculosis ICD9 codes under ‘010’ in the ‘infectious and parasitic diseases’ chapter of ICD9 codes).
In addition, we used the ICD9 coding system to generate comparison groups (‘controls’) for all case groups, which included all patients that did not have a prevalent ICD9 code belonging to a specified list of disease exclusions defined for each case group. The exclusions for most diseases closely followed the existing section groupings in the ICD9 hierarchy, which groups related conditions. Control groups for CD, for instance, excluded CD, ulcerative colitis and several other related gastrointestinal complaints. Similarly, control groups for myocardial infarction excluded patients with myocardial infarctions, as well as angina and other evidence of ischemic heart disease. There are 105 unique control exclusions groups. The custom ICD9 case and exclusion groupings are available from http://knowledgemap.mc.vanderbilt.edu/research.

The Korean Corneal Disease Study Group (KCDSG) is an independent, non-profit, academic society whose members comprise the most active corneal subspecialists in Korea. In 2009, the initial survey on the definition, diagnosis, severity grading, and management of dry eye disease was conducted among the members of the KCDSG. In this survey, we found that 78.8% of KCDSG members use the DEWS classification [3 (link)] as diagnostic guidelines of dry eye disease, while 21.2% use guidelines proposed by the DTS group [2 (link)]. KCDSG members also responded that they consider subjective symptoms, tear film breakup time (TBUT), and signs of ocular surface inflammation of more diagnostic value than other parameters. Based on the results of this survey, along with a review of the contemporary literature with regard to definition, classification, and treatment recommendations for dry eye, the subcommittees held face-to-face meetings to reach a consensus on the issues related to the definition, diagnosis, severity grading, and treatment recommendations for dry eye disease. New guidelines for the diagnosis and management of dry eye disease were adopted as shown in Tables 1 and 2. These guidelines were based on DEWS guidelines and modified to simplify the grading scheme so that they could be used more easily in clinical practice.
Dry eye disease was defined as "a disease of the ocular surface that is associated with tear film abnormalities." We agreed that a patient should be diagnosed with dry eye disease when he or she has at least one symptom and one objective sign. In the diagnosis guidelines, dry eye symptoms included ocular symptoms (such as dryness, discomfort, foreign body sensation, and pain) and visual symptoms (such as blurring or vision fluctuation). Ocular surface staining score by the Oxford system [9 (link)], TBUT, and Schirmer-1 test score were used as objective signs for diagnosing dry eye disease. Conjunctival injection, lid problems such as blepharitis, trichiasis, keratinization, or symblepharon, and tear film abnormalities such as debris, decreased tear meniscus, and mucus clumping, were considered signs of ocular surface inflammation, but these findings were not considered during the grading of disease severity. The severity level of the disease was determined when both designated symptoms and signs were present at a certain level. If there was a discrepancy between the patients' symptoms and signs, the severity level was determined according to the severity level of the objective signs. When several objective signs were present at different levels, the severity level of the disease was determined following ocular surface staining. In addition, we introduced a provisional category of "dry eye suspect," which is not listed on the grading scheme. The patient was diagnosed with suspected dry eye when he or she had only dry eye symptoms without any objective signs. This was to evaluate the distribution of disease severity at the initial visit, and the treatment recommendation did not include the category of "dry eye suspect."
Detailed treatment options for each particular level from level I to level IV were recommended as shown in Table 2.