Anomalies of Accommodation

Ocular accommodation is an integral visual function that optimizes the visual perception through the focusing ability of the crystalline lens. This closed-loop system constantly interacts with the oculomotor system for finer focusing and alignment of the eyes under naturalistic binocular viewing conditions.

This write-up is intended to provide an overview of the commonest anomalies of accommodation encountered by an eyecare practitioner through case-based learning. For detailed reading, the readers are requested to refer to Scheiman & Wick.¹ The table below provides an overview of the commonest clinical signs, and symptoms seen in different anomalies of accommodation. ^{1, 2}

Case 1:

A 19-year-old college student reported with complaints of eyestrain associated with reading and playing video games. The symptoms begin after 10-20 minutes of near work and is associated with pain around the eyes. His unaided visual acuity was 6/6, N6 in both the eyes and he has never used glasses so far. The rest of the eye health examination was normal and the patient’s medical history was unremarkable.

Figure 2 *MEM – Monocular estimate method dynamic retinoscopy; AF: Accommodative facility (with +/-2.00 DS accommodation flippers)

The baseline binocular vision assessment (Figure 1) points out the fact the near points of accommodation are below the age-expected norms.^3,4 Though the near point of convergence appears borderline, given the fact that the accommodation amplitudes are reduced, the accommodation parameters need to be investigated in detail prior to making the diagnosis. The further assessment also indicated an increased lag of accommodation assessed using the MEM retinoscopy and difficulty with minus lenses in accommodative facility testing. Based on the relative accommodation findings, a near addition of +1.00 DS was prescribed as a primary management option followed by in-office vision therapy. The patient reported significant improvement in asthenopic symptoms, with concurrent improvement in clinical parameters (Figure 2). The near addition was later weaned off with home vision therapy provided as maintenance therapy.⁵

Case 2:

A 29-year-old software professional reported with complaints of intermittent blurring of distance vision followed by 30 minutes of near work. His unaided visual acuity was 6/6, N6 in both the eyes, and his refraction was insignificant to be contributing to the symptoms. The rest of the eye health examination was also normal and the patient’s medical history was unremarkable.

*MEM – Monocular estimate method dynamic retinoscopy; AF: Accommodative facility (with +/-2.00 DS accommodation flippers)

The baseline binocular vision assessment (Figure 3) indicates poorer accommodative facility and also difficulty in both stimulating and relaxing accommodation. This is typical of accommodative infacility, which has been reported to be the commonest binocular vision dysfunction.⁶ Visual hygiene measures such as frequent blinking, frequent breaks implanting the 20-20-20 rule, and vision therapy to improve accommodation parameters are efficient in improving accommodation infacility and restoring the accommodation parameters to normal ranges.

The objectives of vision therapy in accommodation anomalies aims at improving the amplitudes, response, and dynamics of accommodation using appropriate tools and techniques. The commonest vision therapy techniques used in the management of accommodation anomalies include but not limited to Hart chart, accommodation flippers and word rock card, and loose lens accommodation rock. ¹ Providing optimal refractive correction, and near addition in required cases are the primary management options before initiating vision therapy.¹ Following vision therapy, significant improvements were reported by the patient with respect to the asthenopic symptoms with concurrent improvements in parameters of the accommodation facility (Figure 4). The cases illustrated in this write-up depict the commonest presentations of anomalies of accommodation in a clinical set-up and proposes a conceptual framework for diagnosis and management from an evidence-based perspective.