Test-retest reproducibility of accommodative facility measures in primary school children

Examining the Validity of a New Method for the Objective Assessment of Binocular Accommodative Facility (2Q-AF Test): A Comparison with ± 2.00 DS Lens Flippers

PURPOSE

Recent technological advances have permitted to objectively record the accommodative response while shifting between two different levels of accommodation. This study is aimed at examining the concurrent validity of a new objective method for the qualitative and quantitative assessment of binocular accommodative facility, which is named 2Q-AF test, in comparison to the ±2.00 DS lens flippers.

METHODS

Fifty-six individuals took part in this study (36 healthy young adults [24.4 ± 3.2 years] and 20 children [12.2 ± 0.4 years]). Participants randomly performed the 2Q-AF and the ±2.00 DS lens flipper tests. For the 2Q-AF test, a binocular open-field autorefractor was used to record the magnitude of accommodative response during a 60-sec period, while participants repeatedly changed fixation from a 5 m to a 40 cm chart when clarity of vision was achieved at each level. Due to the advantages of the proposed method, we have determined the number of cycles and the 2Q-AF score, with the latter also considering the accuracy of changes in accommodation. A standard procedure was followed for the ±2.00 DS flipper test.

RESULTS

Our data exhibited a moderate association between the number of cycles with the ±2.00 DS lens flippers and the number of cycles in the 2Q-AF test in the group of young adults (p = .005, r = 0.46 [0.15-0.68]) and children (p = .007, r = 0.58 [0.19-0.81]), whereas a stronger relationship was observed when considering the number of cycles with the ±2.00 DS lens flippers and the 2Q-AF score (young adults: p < .001, r = 0.83 [0.69-0.91]; and children: p < .001, r = 0.78 [0.52-0.91]).

CONCLUSIONS

The current findings show that the 2Q-AF test is a valid method for accommodative facility assessment, as suggested by its good levels of reliability and validity. This method allows to examine the accommodative facility in qualitative terms and solve most of the limitations associated with the ±2.00 DS lens flipper test.

Changes in accommodative function following small-incision lenticule extraction for high myopia

PURPOSE

To examine whether the amplitude of accommodation, the accommodative response, and the accommodative facility is affected and correlated with changes in higher-order aberrations for patients with high myopia surgically treated with small-incision lenticule extraction (SMILE).

METHODS

35 highly myopic eyes (myopic spherical equivalent of at least 6 diopters) of 35 patients treated with SMILE were included. Assessments were made before and 3 months after surgery. Donders push-up-method was used to measure the amplitude of accommodation. The accommodative response was assessed using an open-field autorefractor"Grand Seiko WAM-5500" (Grand Seiko Co. Ltd., Hiroshima, Japan) in combination with a Badal optometer and stimuli of accommodation at 0.0, 0.5, 1.25, 2.0, 3.0, and 4.0 D, respectively. Accommodative facility was measured at 40 cm with ±2,00D flipper lenses. All measurements of accommodation were performed monocularly with the refractive error corrected with soft contact lenses.

RESULTS

The amplitude of accommodation did not change statistically significantly (mean difference -0.24 D (SD 0.98), 95% CI of mean difference -0.58 D to 0.11 D, paired-sample t(34) = -1.39; P = 0.17). The accommodative responses at 0.0, 0.5, 1.25, 2.0, 3.0, and 4.0 D did not statistically significantly change either (F(6,29) = 1.15; P = .36). Finally, the accommodative facility was also unchanged with a mean difference of 1.11 cycles per minute (SD 5.11, 95% CI of mean difference -0.64 to 2.87, paired-sample t(34) = 1.29; P = 0.21). No clinically significant associations between changes in accommodation and higher-order aberrations were found.

CONCLUSIONS

SMILE does not alter the amplitude of accommodation, the accommodative response, nor the accommodative facility for highly myopic patients, and the surgically induced corneal higher-order aberrations do not affect the accommodative function.

Accommodation and stereopsis in adults with traumatic brain injury

BACKGROUND

Traumatic brain injury has many adverse effects on visual functions. The aim of this study is to evaluate accommodation, stereopsis deficits and visual symptoms in Chinese patients with traumatic brain injury.

METHODS

This is a cross-sectional study that included 22 patients with traumatic brain injury and 22 controls; the refractive status, stereoacuity, and accommodative ability of each subject were measured.

RESULTS

Patients with traumatic brain injury were significantly more symptomatic than controls (p < 0.001). Near stereoacuity thresholds were significantly elevated in patients with traumatic brain injury compared to controls (p < 0.001). Accommodative amplitude (right eye: p = 0.007; left eye: p = 0.01; both eyes: p = 0.002) and accommodative facility rates (right eye: p < 0.001; left eye: p < 0.001; both eyes: p < 0.001) were significantly lower in patients with traumatic brain injury, for whom there were no significant differences between the accommodative facility rates of the pre- and post-three-minute binocular flipper sessions (p = 0.51). Patients with traumatic brain injury showed greater accommodative lag to 2.5 D (p = 0.03), 3 D (p = 0.03), 4 D (p = 0.004) and 5 D (p = 0.001) stimuli, but not to the 2 D (p = 0.10) stimulus. The regression equation of accommodative lag to stimuli was steeper for the traumatic brain injury group (slope: p = 0.01; y-intercept: p < 0.0001). There were also significant correlations between visual symptoms and clinical findings including binocular accommodative amplitude (r = -0.480, p = 0.001), binocular accommodative facility (r = -0.445, p = 0.004) and stereopsis (r = 0.457, p = 0.002).

CONCLUSION

Patients with traumatic brain injury have deficits in accommodation and stereopsis.