What is the expected amplitude of accommodation in a healthy child?

Appeared in: INI-CET EXAM -2026

Explanation

The amplitude of accommodation refers to the maximum increase in the eye's refractive power, measured in diopters (D), to maintain a clear image as an object is brought closer.
In a healthy child, the crystalline lens is highly elastic, allowing for a significant change in shape and power.
The power of accommodation is highest in childhood, averaging about 14 D, which allows children to focus on objects very near to their eyes.
This ability progressively declines with age due to the lens becoming harder and less elastic, a condition known as presbyopia.

Option A: An amplitude of 2D is very low and is characteristic of an older adult, typically someone in their 50s, who has significant presbyopia.
Option B: An amplitude of 5D is the average for a 40-year-old. At this stage, the loss of accommodation becomes symptomatic, and individuals often require reading glasses for the first time.
Option D: An amplitude of 25D is a physiologically unrealistic value for the human eye's accommodative system at any age. It far exceeds the known maximum capacity of the crystalline lens and ciliary muscle.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Physiology of Vision: Amplitude of Accommodation as background academic context rather than a clinical decision trigger.
Understanding the normal range of accommodation helps in identifying abnormalities like accommodative insufficiency or spasm in children and adolescents.
This concept is fundamental to explaining presbyopia to patients and justifying the need for reading glasses or bifocals as they age.
Nurses performing vision screenings in schools can use this knowledge to understand why children can read at very close distances without strain, which is normal for their age.

How to Approach the Question

First, identify the key term in the question: 'amplitude of accommodation'. Recall its definition as the eye's focusing power.
Next, note the subject: 'a healthy child'. This is a crucial qualifier.
Relate the concept to the subject. Remember that accommodative ability is at its peak in childhood and declines with age.
Evaluate the given options. You are looking for the highest plausible value that represents this peak ability.
Eliminate the lower values (2D, 5D) as they correspond to older ages and the onset of presbyopia.
Eliminate the extremely high value (25D) as physiologically improbable. This leaves 14D as the most accurate and standard value for a child's peak accommodation.

Concept Tested & Keywords

Concept Tested: Physiology of Vision: Amplitude of Accommodation
Stem keywords: amplitude of accommodation, healthy child, expected
Lead-in keywords: What is
Clinical cues: Age/sex group narrows the expected diagnosis, intervention, or normal reference range.
Negative lead-in flag: false

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E6 Physiology Guyton 4SAE Part 3 p. 140-142

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