Abstract
Accommodation disorders are associated with a host of etiologies. Children with accommodative disorders can present with various symptoms including blur, fluctuating vision, eye pain, burning sensation, tired eyes, asthenopia, headaches, fatigue with near work, and excessive rubbing, blinking, or tearing. This chapter provides an overview of accommodation testing on pediatric patients in the clinical setting. The author describes the indications for accommodation testing and provides clinical pearls for testing accommodative function in children. The chapter covers the specific tests, equipment required, and step-by-step procedures for testing accommodative amplitude, accommodative response, and accommodative facility.
TopBackground
Accommodation disorders are associated with a host of etiologies. In healthy children, accommodative disorders are associated with convergence disorders, emotional stress and uncorrected refractive errors, particularly hyperopia (Chrousos et al., 1988). Associated ocular conditions include ocular inflammation and sclerosis of the crystalline lens. Neurologic conditions including head trauma, cranial nerve III palsy, pharmacologic agents, and encephalitis, can negatively affect accommodation. Additionally, systemic conditions that can affect accommodation include myasthenia gravis, diabetes, hypertension, Gillian Barr syndrome, tuberculosis, endocrine disorders, and syphilis (Cooper and Panariello, 1988; DeRespinis et al, 1989; Master et al., 2016; Moss et al., 1987).
The eye structures involved in accommodation are the crystalline lens, ciliary muscle, and zonule fibers which attach the lens to the ciliary muscle. Figure 1 shows the ocular structures involved in accommodation.
Figure 1. Anatomy of the accommodation structures
Optical accommodation occurs to keep an object in focus on the retina while the distance from the object to the eye changes. With the eyes viewing a distant object, light rays are nearly parallel and accommodation is not needed to bring objects into focus. When the eye is relaxed, in the unaccommodated state, the ciliary muscles are relaxed, the zonule fibers are taut, and the lens is less convex. Figure 2 shows the eye in an unaccommodated state.
Figure 2. The eye in an unaccommodated state
Key Terms in this Chapter
Fused Cross-Cylinder Test: A method of evaluating accommodative response using ±0.37 D cylinder lenses and a grid target of horizontal and vertical sets of lines.
Accommodative Infacility: The inability of the eye to alternately stimulate and relax focus to changes in stimuli.
MEM Retinoscopy: The Monocular Estimate Method measures the accuracy of a patient’s accommodative system when viewing a target at near utilizing lenses to neutralize the retinoscopy reflex.
Lens Flipper Test: An evaluation of accommodative facility utilizing +2.00 D and -2.00 D lenses that are alternately cleared while viewing an accommodative target at near.
Accommodative Excess: When the accommodation response exceeds the stimulus demand required to focus.
Nott Retinoscopy: A method of measuring the accuracy of a patient’s accommodative system with a retinoscope held at near and changing the distance of an accommodative target until a neutral reflex is observed.
Amplitude of Accommodation: The maximum amount of refractive power the eye can stimulate at a given distance.
Push-Up/Pull-Away Method: A test to measure accommodative amplitude utilizing an accommodative target presented at near that is either moved closer, or away from the patient’s eye with an endpoint of first sustained blur.
Minus-Lens Test: A method of measuring accommodative amplitude using concave lenses in increasing power while patient views an accommodative target at near.
Accommodative Insufficiency: A visual dysfunction with stimulating accommodation.