LOW VISION THERAPY: A STEP BY STEP GUIDE

 

B Y    A G U N L O Y E     F E M I   O D .

Low vision can be defined as a bilateral decrement to visual acuity or visual field resulting from a disruption of the visual system. This decreased acuity or field results in an impaired ability to perform work, leisure, or daily living activities. Low vision rehabilitation is like physical therapy for someone who has lost a limb. Its purpose is to develop strategies to maximize or substitute for diminished sight in order to maintain independence and a sense of self-worth. This rebuilding and reinforcement of the visual foundation is accomplished through identification of goals, introduction to assistive devices, and training. 

Rehabilitation is not just an introduction to low vision devices. Actually, that may not occur until some time into the program, after the patient has gone through evaluation and training. Only then can appropriate recommendations for low vision devices be made. Various forms of low vision therapy can increase the patient's ability to perform work, leisure, or daily living activities. Low vision therapy increases both physical and psychological health of the patients. Research has shown that people with low vision tend to have more emotional difficulties and a higher risk of accidents than normally-sighted individuals. Patients who have undergone rehabilitation, however, have reported significant improvements in their functional abilities, a high rate of continued use of low vision devices, improvement in reading and distance vision, and general satisfaction with the quality of life.

LOW VISION PATIENT EXAMINATION

 A low vision examination should detail the kinds and the quality of visual deficits afflicting patients and how they are adapting to their vision loss. This may include a chief complaint, as well as social, functional, and ocular health history as detailed in the sample examination form. The first step is assessment of visual functions through tests and techniques adapted to fit the client’s visual impairment.

 LOW VISION REHABILITATION AND TRAINING 

The goals improvement in activities of daily living (often called independent living skills), computer use, and counseling. Vocational rehabilitation might be part of the program if the client needs to remain employed. If that is the case, several psychometric assessments would be made to evaluate current skills as they relate to the employment. If the patient’s condition is severe enough, orientation and mobility training might also be included. For patients with mild vision loss, simple environmental modifications may be enough to perform daily living tasks. 

People with moderate to severe visual loss will also benefit from environmental modifications, but they  will need additional experience with low vision devices and technology to help maximize their vision. Occupational therapy practitioners working with persons with vision loss focus on increasing the person's level of independence with activities of daily living that have been compromised by visual impairment. The services can be provided in a clinic setting or in the person's home or work environment. 

Occupational therapists work with persons with age-related macular degeneration, diabetic retinopathy, glaucoma, retinitis pigmentosa, cataracts, visual field deficits from CVA, and traumatic brain injuries. Occupational therapists train people in the use of the prescribed optical devices (eg, high power readers, magnifiers, telescopes, microscopes, video magnifiers) to successfully integrate the devices into daily livings tasks and activities. Difficulty with reading is the most noticeable result of vision loss. Tasks that present the greatest challenge are those that have low contrast features or small print. 

Occupational therapists also train people in non-optical options, such as the use of contrast and illumination, to increase visibility. In a clinic setting or during a Functional Home Living Assessment or Workplace Assessment, the occupational therapist can assist a person with the following: 

• Ensure lighting is optimal for task performance by evaluating overhead, ambient, and task lighting 
• Use contrast to increase visibility of key objects and landmarks 
• Use various materials to mark features of objects to increase their visibility or allow another sensory system to identify them (eg, colored plastic tape, tactile adhesive dots, Hi marks-tactual marking substance) or supplement visibility with auditory or tactile cues. 
• Ensure even illumination and determine maximum lumens, minimum glare, flexible placement of lighting. 
• Determine the type of lighting that works best (eg, incandescent, fluorescent, halogen, full spectrum). Ergonomic completion of tasks to alleviate muscle strain and fatigue.

For persons who have a central scotoma or blind spot, an occupational therapist assesses the awareness and ability to use the preferred retinal locus (PRL) in direct eye movement. This ability is highly correlated to the ability to read. Visual training skills can be implemented with pre-reading and writing exercises designed to improve accuracy and efficiency of reading and then graded to include continuous text. Areas assessed include the following: 

• Ability to locate and fixate on a target 
• Ability to perform saccades between a target 
• Ability to perform smooth pursuits or tracking 
• Ability to view target at distance and near 
• Reading performance to determine critical print size, maximum reading speed, reading comprehension, and reading endurance

REHAB TARGET 

Adapting the home for safety and navigation 

 Improving lighting conditions 

 Preparing meals 

 Labeling medications, clothing etc. 

 Writing 

 Keeping financial records 

 Personal grooming 

 Using magnifiers for easier reading 

 Systematizing shopping and payment. 

LOW VISION EXAMINATION 

Visual acuity and refractive status 

Evaluation of ocular health; IOP and funduscopy. 

Visual field test 

Contrast sensitivity 

Brightness acuity tester 

Color vision test 

Ocular motility test