Vision Assessment

Assessments of Vision

The vision system can be evaluated from many different perspectives. Several professions are in the business of assessing vision, and each has a unique set of assessment strategies and goals. There are categorical assessments; functional vision evaluations, developmental tests, perceptual and motor judgements, etc. And there are the three conceptual distinctions between assessments of impairment, disability, and handicap. Finally, it is possible to do a systems analysis of the various vision subsystems. All of these assessment approaches overlap, and this section contains redundancies.

Please note that I am not an expert in each of the professions listed below. I was trained many years ago as an optometrist, but for the past nineteen years I have worked in the rehabilitation field, as an orientation and mobility specialist. Even my comments about mobility may not be as complete or accurate as my colleagues would like. Certainly, since I have been away from optometry for so many years, that noble profession has evolved considerably, and my description of the field is incomplete. So, please take no offense if I have incompletely or inaccurately portrayed your profession. My goal is to afford the highest respect for the professionals in each and every field. That being said, I would also like to hear from those who would like to see a rewording of my descriptions. Don't be shy.

By Profession

Ophthalmology

Optometry

Blind Rehabilitation

Psychology

Education (LD)

Occupational Therapy

Ophthalmology

Ophthalmologists are medical doctors. Their main concern is the health of the eye. They also follow a medical model for the delivery of services. This model is excellent for diagnosing and treating medical problems, but is less successful addressing the needs of chronically affected individuals, those with low vision or developmental disabilities, for example. The ophthalmologist is the front line vision professional responsible for medical care of patients with vision impairments. Medical problems must be addressed before rehabilitation models can be put into action. Quite often, ophthalmological monitoring is a life long necessity for individuals with low vision, with re-examinations taking place every six to twelve months.

A medical assessment looks for signs of disease or trauma, usually at the level of the eyeball. Neuro-ophthalmologists assess vision impairments that occur at higher levels of the optical system; in the occipital lobe or deeper into the brain. A medical assessment can offer valuable inferences about function, but cannot replace actual task evaluations of educators and rehabilitation specialists. Surgeries and drug therapies must be addressed early, and usually before rehabilitation and special education strategies (drug therapies often occur concurrently).

Ophthalmologists are impairment specialists. They are very "eyeball" centered. They are specialists in the function and repair of body parts and body systems. They are not the experts when it comes to disability or impairment. After doctors do all they can to fix a body part or system, they refer patients with "chronic" conditions to disability specialists.

bar

Optometry

Optometrists bridge the gap between the medical and the rehabilitative fields. They are trained to diagnose medical problems, and to refer the more serious cases that require surgery to ophthalmologists. Optometrists and neuro-optometrists also treat many medical conditions using drug therapies. Optometrists often work in cooperative practices with medical practitioners. They also work with educators and rehabilitation specialists to address visual disability.

Optometrists are primarily impairment specialists. They diagnose and treat body parts and body systems that relate to the vision system. Some optometrists, however, are specialists in vision disability. They work closely with teachers and with rehabilitation professionals to understand and address the real world tasks faced by chronically affected individuals. Assessments conducted by optometrists often depend on the specialty area of the doctor. Developmental optometrists conduct disability assessments relating to perceptual processing, low vision specialists conduct functional assessments that measure the ability to see using various magnification and light altering systems, while "standard" practitioners may conduct neither of these disability assessments choosing instead to focus on routine impairment level assessments that determine the need for spectacle corrections (etc.).

bar

Blind Rehabilitation

Mobility specialists and blind rehabilitation professionals do real world task analysis. They are purely disability/handicap specialists. They do no diagnostic or medical assessments of the kind referred to here as impairment. Disability assessments take place in the real world, and are often more "accurate" and useful than the test results from impairment measurements. For example, two individuals with identical acuities (20/200) may have entirely different abilities to function. A mobility assessment occurs at street crossings, in grocery stores, in shopping malls, in school classrooms and hallways, and in the home. Students are asked to read real clocks, to find information from phone books or text books, to describe facial or full body gestures, and so on. Students are assessed on their ability to use magnification systems in the real world.

When working with chronically affected individuals, the skills of professionals at all levels must be used, and the results from all the tests must be studied and summarized into a plan of action. This study and plan usually is the responsibility of the disability specialist.

bar

Psychology

Education

Occupational Therapy

By type

Functional

Perceptual

Motor

Developmental

Genetic

Low Vision

Using Impairment, Disability, Handicap

Impairment: Assessment of body parts

Ophthalmology

Optometry

Low Vision Specialists

Pediatric Ophthalmology

Developmental Optometrist

Neuropsychology

Neurology

Neuro-ophthalmology

Retinal Specialist

Disability: Assessment of tasks

Mobility

Rehabilitation

Teacher of VI

Teacher Consultant

Occupational therapist

Optometry

bar

Orientation and mobility disability assessment

In the discussion of the roles of vision, nine categories were listed. these nine jobs of the vision system serve as good categories for assessment.

Identification

Navigation

Gait

Balance

Posture and Gesturing

Security

Communication

Verification

Aesthetics

Handicap: Assessment of social roles

Vocational counselors

Social worker

Educators

Rehabilitation counselors

Systems analysis

Ocular media

Retina

Retinal tract to occipital lobe

Subcortical tract from LGN

Occipital/temporal tract

Occipital/parietal/frontal tract

bar

Return to the index page Return to the top of this page.

Back to the Vision home page Ahead to "Vision and the brain"