Vision

Susan E. Edmonds
Ryan P. Edmonds

BASICS

DESCRIPTION

Condition where there is a permanent loss in vision due to any disease or disorder where some usable vision remains but desired life function is limited. Some common causes are macular degeneration, diabetic retinopathy, optic neuropathy, and disorders of the visual pathways.

Geriatric Considerations

• Extra time is required to evaluate this population.

• Concentration on near tasks is required.

• Clinical picture can be affected by dementia and cognitive disorders.

Pediatric Considerations

• Accommodation can compensate for magnification.

• Presbyopia occurs very early due to the need for close working distances.

• Telescopes and distance magnification often required.

EPIDEMIOLOGY

Incidence

1/28 for Americans over 40

Prevalence

• 3.3 million adults in the USA

• 0.65–2.75/1000 children

• Difficult to determine due to different definitions for low vision and impairment

RISK FACTORS

• Follows cardiovascular risk factors

• Genetic

• Diet

• Exercise

• Smoking

• UV light exposure

Genetics

• Follows ocular genetic patterns for many causes

• Retinitis pigmentosa

• Stargardt’s

• Optic atrophy

• Macular degeneration

GENERAL PREVENTION

• Maintain ocular health

• Protect eyes from UV light

• Maintain cardiovascular health

• Control systemic disease

• Diabetes

PATHOPHYSIOLOGY

• Varies with underlying cause

• Media disorders

• Retinal disorders

• Neurological disorders

ETIOLOGY

Ocular disorders that result in permanent vision loss

COMMONLY ASSOCIATED CONDITIONS

• Diabetes

• Vascular disorders

• Macular degeneration

• Glaucoma

• Optic neuropathy

DIAGNOSIS

HISTORY

• Medical

• Ocular

• Functional

• Reading

• Driving

• Educational needs

• Personal independence

PHYSICAL EXAM

• Visual acuity

• Distance

• Near

• Slit lamp exam:

– Media integrity

• K reading or topography

• Fundus examination:

– Photographic

• Refraction:

– Encourage eccentric viewing

– Trail frame

– Large steps ±0.50, ±1.00, ±2.00

– Diagnostic tests & hand held cross cylinder testing

– Bracket to end point

• Magnification testing:

– Inverse of distance acuity formula 20/200 …200/20 = +10.00 Add

– Test at focal length of Add

– Increase Plus until target near acuity is achieved (0.8 M)

• Reading function testing:

– Sloan Cards, MN Read, or equivalent

• Telescope testing:

– 2.2× wide angle telescope over best refraction in trial frame

– Increase magnification until desired distance acuity is achieved

DIAGNOSTIC TESTS & INTERPRETATION

Diagnostic Procedures/Other

• Refractive, magnification testing, and reading tests:

– Provide an excellent overview of the patient’s function:

Are the patient’s specific goals realistic?

Can rehabilitation bridge the gap?

• Rehabilitation will require repetitive reading tasks at home:

– Follow-up visits are required to monitor progress and introduce other low vision aids to meet patient goals.

– Visual fluctuations or changes in the disease will require reevaluation.

TREATMENT

ADDITIONAL TREATMENT

Rehabilitation

• First line:

– Establish eye movement patterns consistent with reading or the accurate identification of details:

Large print

Regular print

• Second line:

– Magnification devices to achieve specific goals

– Near spotting tasks like shopping, menus, setting stove, thermostat, and dials

– Hand held magnifiers

– Reading books, magazines, mail

– Spectacles mounted microscopes (high adds)

– Personal management

– Closed circuit TV or electronic magnifiers

– Distance tasks

– Telescopic lenses

General Measures

• Occupational therapy

• Home evaluation

Issues for Referral

• Depression or mental health issues

• Psychology/psychiatry

Additional Therapies

• Close follow-up with specialty ophthalmology to manage underlying ocular disease

• Close follow-up with other medical specialties to manage underlying systemic disease (diabetes)

SURGERY/OTHER PROCEDURES

If low vision management cannot achieve required life goals, aggressive surgical options must be considered.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Patients need aggressive follow-up during rehabilitation and introduction of new low vision aids:

– 2–4 weeks, 3 months, 6 months

Patient Monitoring

Annual

DIET

Diet or supplements consistent with management of underlying ocular problem, i.e., Macular Degeneration – AREDS recommendations

PATIENT EDUCATION

• Educate the patient on the underlying ocular disease

• Educate the patient on goals and progress of low vision rehabilitation

• Educate the patient on required lifestyle changes (i.e., driving)

• Educate the patient on other resources that may be available to assist him or her:

– Support groups

– Para-transit

– Large print

• Review new low vision aids and strategies on annual follow-up

PROGNOSIS

• Based on underlying ocular disease

• Based on underlying systemic disease

COMPLICATIONS

• Mental health issues

• Progression of related disease

ADDITIONAL READING

• Edmonds SA, Edmonds SE. New evidence that vision rehabilitation is a key component in the management of patients with macular degeneration. Curr Opin Ophthalmol 2006;17(3):278–280.

• Faye EE. Clinical low vision, 2nd ed. Boston: Little Brown and Company, 1984.

• Freeman P, Jose R. The art and practice of low vision. Boston: Butterworth Heinemann, 1997.

• Rosenthal B, Thompson B. Awareness of age-related macular degeneration in adults: The results of a large-scale international survey. Optometry 2003;74(1):16–24.

• Scheiman M, Scheiman M, Whittaker SG. Low vision rehabilitation: A practical guide for occupational therapists. Thorofare, NJ: Slack Inc., 2006.

CODES

ICD9

369.9 Unspecified visual loss

CLINICAL PEARLS

• Positive attitude throughout evaluation and treatment is required to manage low vision problems

• Manage refractive problems first

• Consider contact lenses

• Consider prism

• Extensive counseling and patient education

• Follow patients closely, consider changes in management plan, and work closely with referring eye doctors and other specialists

• Refer for ancillary services