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A Review of Low Vision Rehabilitation
Mark E. Wilkinson, OD
Contents
- Introduction
- What is Low Vision Rehabilitation?
- Definitions
- Codes for Low Vision Rehabilitation Diagnoses and Procedures
- Other Vision Impairment Classification Systems
- Epidemiology of Visual Impairment
- Rehabilitation Approach to Low Vision
- The Low Vision Rehabilitation Examination
- Comprehensive Case History
- Determination of the Patient's Vision Enhancement Needs
- The Examination Sequence
- Determination of Refractive Errors
- Visual Function Tests
- Health Assessment
- Applicability of Selected Low Vision Devices
- Magnification
- Vision Rehabilitation Devices
- Rehabilitation Instruction
- Report Writing
- Low Vision Practice Management Considerations
- Conclusion
- References
- Appendix: Computer Software Available for Low Vision Patients
Codes for Low Vision Rehabilitation Diagnoses and Procedures
The conditions requiring low vision rehabilitation services are specified using the usual ICD-9 codes. In addition, for compensation for low vision rehabilitation services, another standard set of diagnostic and procedure codes is used.
The International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) is based on the World Health Organization's Ninth Revision, International Classification of Diseases (ICD-9). ICD-9-CM is the official system for assigning codes to diagnoses and procedures associated with hospital utilization in the United States. (http://www.cdc.gov/nchs/about/otheract/icd9/abticd9.htm)
The set of codes used for specifying the degree of a patient's visual acuity impairment is based on the ICD-9 Classification of Visual Acuity Impairment designating medical necessity for rehabilitation:
- Moderate Impairment: 369.16-369.25; Best corrected acuity less than 20/60 (6/18)
- Severe Impairment: 369.12-369.22 (legal blindness); Best corrected acuity less than 20/160 (6/48) or visual field less than or equal to 20 degrees
- Profound Impairment: 369.06-369.08; Best corrected acuity less than 20/400 (6/120) or visual field less than or equal to 10 degrees
- Near Total Impairment: 369.01-369.04; Best corrected acuity less than 20/1000 (6/300) or visual field less than or equal to 5 degrees
- Total Impairment: no light perception
Impairment can also take the form of visual field loss. Field loss codes and definitions from the ICD-9 Classifications of Visual Field Loss designating medical necessity for rehabilitation are as follows:
- 368.4: scotoma involving the central area (within 10 degrees of fixation)
- 368.45: generalized contraction or constriction
- 368.46: homonymous bilateral field defects
- 368.47: heteronymous bilateral field defects
Along with disease codes, the ICD-9 classification codes for visual acuity and visual field loss should be used when billing Medicare, Medicaid, or other insurance providers so as to better demonstrate the need for your services.
Other Vision Impairment Classification Systems
What follows are classifications for describing visual acuity or visual field loss that avoid the use of the term “legally blind” and are designed to give be a better description of the vision loss.
The WHO Classification of Visual Acuity Loss provides the following definitions and acuity ranges:
- Normal acuity: 20/25 (6/7.5) or better
- Mild vision loss: 20/32 (6/9.6) to 20/63 (6/18.9)
- Moderate vision loss: 20/80 (6/24) to 20/160 (6/48)
- Severe vision loss: 20/200 (6/60) to 20/400 (6/120)
- Profound vision loss: 20/500 (6/150) to 20/1000 (6/300)
- Near blindness: less than 20/1000 (6/300)
- Blindness: no light perception
American Medical Association's Classification of Visual Field Loss (Based on the American Medical Association's Guide to the Evaluation of Permanent Impairment, 5th Edition, Chapter 12 - The Visual System American Medical Association's Guide to the Evaluation of Permanent Impairment, 5th Edition, Chapter 12 - The Visual System) provides the following definitions and usable remaining field ranges:
- Normal: 120 degrees or better of usable field
- Mild vision loss: 80 to 119 degrees of usable field
- Moderate vision loss: 21 to 79 degrees of usable field
- Severe vision loss: 16 to 20 degrees of usable field
- Profound vision loss: 8 to 15 degrees of usable field
- Near blindness: 1 to 7 degrees of usable field
- Total vision loss: no light perception
Epidemiology of Visual Impairment
Vision loss is a common problem as we age. The estimated number of individuals who are visually impaired in the US varies from 3.5 to 14 million, depending on which definition of visual impairment is used.
In 1995, the Lighthouse National Survey on Vision Loss estimated the following:
- 13.5 Million Americans 45 years of age and over (1 in 6) say they are visually impaired.
- For Americans age 75 and older, 1 in 4 say they are visually impaired.
Risk factors for developing visual impairment include:
- Aging: Vision Problems in the United States (VPUS) states “The leading causes of vision impairment in the US are primarily age-related eye disease.” By the year 2030, the number of individuals over the age of 60 will double.
- Age-Related Macular Degeneration: VPUS says over 1.6 million Americans, age 50 and older, have late AMD, which they define as dry AMD where atrophy exists, and all cases of wet AMD.
- Cataracts: VPUS says 20.5 million Americans, age 40 and older, or 1 out of 6 in this age range. By age 80, 1out of 2, or half, have cataracts
- Diabetic Retinopathy: VPUS says 5.3 million Americans, age 18 and older, or 2.5% of this population have diabetic retinopathy (this includes those with mild or worse retinopathy, including non-proliferative retinopathy, macular edema, or proliferative changes).
- Glaucoma: VPUS says 2.2 million Americans, age 40 and older, or 1.9% of this population has glaucoma.
- Race: VPUS reports that diabetic retinopathy is more common in Whites, prior to age 40, and more common in Hispanics later in life; Glaucoma is more common in Blacks and Hispanics than Whites.
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