What is Low Vision?

Low Vision, also known as par­tial sight, is an impair­ment that can­not be resolved with con­ven­tional cor­rec­tion devices such as eye­glasses or con­tact lenses. In addi­tion, nei­ther surgery nor med­ica­tion can cor­rect the impair­ments that inter­fere with a person’s daily activities.

Com­mon Con­di­tions Caus­ing Low Vision

Many dis­eases result in low vision or visual impair­ment; Glau­coma, mac­u­lar degen­er­a­tion, cataracts, retini­tis pig­men­tosa and dia­betic retinopa­thy are just a few. Nor­mal vision is 20/20; when vision reaches 20/60, or worse, a per­son starts to expe­ri­ence dif­fi­culty with their daily activ­i­ties. Sim­ple tasks like read­ing or dri­ving a car become a problem.

Low Vision: Com­mon Types

• Gen­er­al­ized haze causes the feel­ing of a glare, coat­ing, or film over the eye that may or may not extend over the entire field of vision.
• Blurred vision causes far and near objects to appear not focused, even when con­ven­tional spec­ta­cle cor­rec­tion is used.
• Periph­eral vision loss, the inabil­ity for the eye to dis­tin­guish objects on one side of the eye or both, includ­ing any­thing directly below and/or above eye level. A person’s cen­tral vision is still present mak­ing objects directly ahead view­able. Typ­i­cally, los­ing periph­eral vision can affect mobil­ity; if severe, read­ing speed can slow due to see­ing min­i­mal words at once (a.k.a. tun­nel vision).
• Loss of cen­tral vision cre­ates a blind spot or blurt, but periph­eral (side) vision is still present. Abil­ity to dis­tin­guish details in the dis­tance, read­ing, and rec­og­nize faces are affected but mobil­ity is usu­ally unaffected.
• Extreme sen­si­tiv­ity to light is present when the eye is over­whelmed by the nor­mal illu­mi­na­tion lev­els. A glare can occur and or a washed out. A per­son may expe­ri­ence dis­com­fort or even pain from nor­mal illu­mi­na­tion levels.
• Night blind­ness causes a per­son to be unable to see in dimly lit areas; restau­rants, movie cin­e­mas, or out­side at night.

Func­tional Vision Problems

Dif­fi­culty Seeing:

• Com­puter Screens
• Gas Flam Height When Cooking
• Read­ing (tele­phone book, mag­a­zines, news­pa­pers, etc.)

Prob­lems:

• Thread­ing a Needle
• Dri­ving
• See­ing Traf­fic or Cross­ing Streets or seeing

Low Vision Exam­i­na­tion: What’s included?

A Health and Med­ica­tion History

• Over­all health of patient and family.
• Patient and fam­ily conditions.
• Med­ica­tions.

A Vision History

• Fam­ily his­tory.
• Recent changes.
• Past treat­ments, med­i­cines, surg­eries, etc.
• Last exam­i­na­tion date.

A Low Vision History

• A time-line from when vision prob­lems began to the present.

An Eye Health Evaluation

• Exter­nal and inter­nal exam­i­na­tion of the eye to deter­mine eye health.

A Low Vision Refrac­tion or Visual Acu­ity Testing

• A Bai­ley Lovie Acu­ity Chart and Fein­bloom Dis­tance Chart are used to help deter­mine clar­ity and sharp­ness of both dis­tance and near vision.

Visual Field Testing

• Deter­mines how much periph­eral vision is present.

Spe­cial­ized Tests to Measure:

• Color vision
• Depth per­cep­tion
• Con­trast sensitivity

Low Vision Aids

• Non-prescription and pre­scrip­tion devices help enhance vision for peo­ple with low vision.

Exam­ples:

• Spe­cial Low Vision Eye Glasses
• Mag­ni­fiers
• Micro­scopic Read­ing Glasses
• CCTV’s (Elec­tronic Read­ing Machines)
• Check-Writing Guides
• Large Print Books
• Tele­scopic Lenses for Dri­ving and Other Dis­tance Tasks
• White Canes

To ensure the cor­rect crutch is used it is best to seek advice from an Oph­thal­mol­o­gist or Optometrist.

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Photo Cred­its

Mike “Dakinewava­mon” Kline
Slick­Films