Heather A. Anderson and Karla K. Stuebing
Optometry and Vision Science VOL. 91, NO. 11, PP. 1290Y1301 November 2014
Reviewed by: Sandy Tran, O.D.
Resident in Vision Therapy and Rehabilitation
Family Eyecare Associates, Fair Lawn, NJ
Accommodation is the process of the change in dioptric power caused by the alteration in the crystalline lens shape to maintain clarity at various distances. Accommodative amplitude is the total accommodative power of the eye. It is widely understood that accommodative amplitude is a function of age, with the greatest amplitude present at a young age with decline over time until there is zero accommodation as presbyopia is reached. Clinical testing for accommodative amplitude can be done in different ways. One test in particular that is widely used due to its quickness and ease is the subjective push up test, where the patient reports first blur when a target is “pushed up” closer to the patient’s uncovered eye. This study analyzes the difference between subjective and objective accommodative testing among preschool and presbyopic subjects.
The study included a wide age range of subjects that compared subjective and objective accommodative amplitudes using three methods: 1) subjective push up 2) objective minus lens and 3) objective proximal stimulation. The subjective push up was done monocularly using a near point rod and a 20/40 letter. The subject was asked to report the first blur and the average of three measurements were taken. The following objective testing was done on the Grand Seiko Autorefractor. The objective minus lens measurement used a 20/40 letter and the accommodative demand was increased sequentially in 1 Diopter steps using minus lenses in a trial frame. The objective proximal stimulated amplitudes were the greatest accommodative response obtained while viewing the 20/40 letter as it increased in proximity from 40 cm to 3.33 cm.
Results revealed that there is a large disparity in subjective and objective accommodative amplitudes with subjective testing highly overestimating amplitudes, especially at the youngest ages between 3 and 5 years old. Although the objective proximal stimulated technique measured greater amplitudes than the objective minus lens measurements, the difference was small (~0.50D). The study found that the largest mean maximum amplitude obtained for any age group did not exceed 9 D.
In summary, between objective and subjective testing for accommodation, the subjective testing highly overestimates the accommodative amplitude among all ages, especially the youngest age group. The study encourages clinician’s to re-consider the mindset that children have vast accommodative ability originally presented by Hofstetter. The finding that children had equal to or less than 9 D of accommodative amplitude has potential implications for the management of uncorrected isometropic hyperopia which has shown to be associated with variable accommodative responses.
Optometry and Vision Science VOL. 91, NO. 11, PP. 1290Y1301 November 2014
Reviewed by: Sandy Tran, O.D.
Resident in Vision Therapy and Rehabilitation
Family Eyecare Associates, Fair Lawn, NJ
Accommodation is the process of the change in dioptric power caused by the alteration in the crystalline lens shape to maintain clarity at various distances. Accommodative amplitude is the total accommodative power of the eye. It is widely understood that accommodative amplitude is a function of age, with the greatest amplitude present at a young age with decline over time until there is zero accommodation as presbyopia is reached. Clinical testing for accommodative amplitude can be done in different ways. One test in particular that is widely used due to its quickness and ease is the subjective push up test, where the patient reports first blur when a target is “pushed up” closer to the patient’s uncovered eye. This study analyzes the difference between subjective and objective accommodative testing among preschool and presbyopic subjects.
The study included a wide age range of subjects that compared subjective and objective accommodative amplitudes using three methods: 1) subjective push up 2) objective minus lens and 3) objective proximal stimulation. The subjective push up was done monocularly using a near point rod and a 20/40 letter. The subject was asked to report the first blur and the average of three measurements were taken. The following objective testing was done on the Grand Seiko Autorefractor. The objective minus lens measurement used a 20/40 letter and the accommodative demand was increased sequentially in 1 Diopter steps using minus lenses in a trial frame. The objective proximal stimulated amplitudes were the greatest accommodative response obtained while viewing the 20/40 letter as it increased in proximity from 40 cm to 3.33 cm.
Results revealed that there is a large disparity in subjective and objective accommodative amplitudes with subjective testing highly overestimating amplitudes, especially at the youngest ages between 3 and 5 years old. Although the objective proximal stimulated technique measured greater amplitudes than the objective minus lens measurements, the difference was small (~0.50D). The study found that the largest mean maximum amplitude obtained for any age group did not exceed 9 D.
In summary, between objective and subjective testing for accommodation, the subjective testing highly overestimates the accommodative amplitude among all ages, especially the youngest age group. The study encourages clinician’s to re-consider the mindset that children have vast accommodative ability originally presented by Hofstetter. The finding that children had equal to or less than 9 D of accommodative amplitude has potential implications for the management of uncorrected isometropic hyperopia which has shown to be associated with variable accommodative responses.
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