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Introduction
Accommodative insufficiency is the most common form of accommodative dysfunction1 and affects pre-presbyopia.2 Although various factors contribute to this condition,3 prolonged near-work or use of digital screens can contribute to the development of accommodative insufficiency.4,5
Individuals with accommodative insufficiency often present with asthenopic symptoms, such as blurred vision, headache, visual discomfort, diplopia, light sensitivity, difficulty in focusing near, and loss of comprehension.2,4–6 In a questionnaire-based study of 99 computer science students, 69.7% had asthenopia. Among students with asthenopic symptoms, 95.7% had refractive asthenopia accompanied by accommodative insufficiency. Therefore, the Convergence Insufficiency Symptom Survey (CISS) questionnaire is crucial for assessing the type and frequency of symptoms before treatment initiation.2,6,7
The primary aim in managing accommodative insufficiency is to identify signs and relieve symptoms. Signs commonly associated with the condition include a decline in the amplitude of accommodation (approximately 2.00 diopters [D] or below the minimum amplitude), as evaluated using the Hofstetter equation 15 – (0.25 × age of the patient).2,8–10 The other signs included increased accommodation lag, reduced positive relative accommodation, accommodative facility, and difficulty in using negative lenses.2 Therefore, treatment could include corrective glasses for refractive error, plus lenses for near-work, and vision therapy.2
Vision therapy is a learning process that requires certain levels of maturity and intelligence. Maintaining clear binocular vision requires appropriate interaction between accommodation and vergence.2 The accommodative and vergence systems adjust the shape of the crystalline lens and eye alignment to produce a clear, single perception regulated through a negative feedback loop. The feedforward crosslink allows mutual accommodative and vergence responses. Therefore, in the presence of accommodative or vergence dysfunction, combined therapy is necessary.11 This method employs precise sensory-motor-perceptual stimulation methods by systematically adjusting target blur, disparity, and proximity to normalize accommodative and vergence systems.11,12 Vision therapy includes exercises and tasks that improve eye coordination and focusing ability at various distances. As a result, it alleviates asthenopic symptoms, including eye strain, headache, and difficulty in reading and concentration.2,13
The Bernell EYEPORT II vision training system (JLEPV2+; Bernell; ced to