Improvement of asthenopia caused by abnormal visual functions via visual training in adult patients

Objective

To analyze the improving effect of visual therapy on the symptoms of asthenopia caused by abnormal visual function in adults.

Methods

A serial case study was conducted.Ninety-three adult patients (186 eyes) with visual dysfunction caused by abnormal visual function who underwent training in the visual training room of the Optometry Center of Tianjin Eye Hospital from October 2018 to October 2019 were enrolled, among which there were 48 males and 45 females.The average age of patients was (30.43±6.39) years old.Binocular visual function examination included vision examination by phoropter, simultaneous vision and stereopsis by Worth 4 Dots test, distance and near heterophoria by Von-Graefe method test, fusion range by rotating prism method, the accommodation reaction by fusion cross cylindrical lens (FCC), the accommodation amplitude by minus technique, the accommodation flexibility and the vergence flexibility by flipper, and a personalized training program was formed on the basis of the above examination results.The training process was divided into initial examination, first review and second review, and each stage containing 5 times of training was followed by a review.The results of the initial examination, first review and second review were compared.The study protocol was approved by an Ethics Committee of Tianjin Eye Hospital (No.KY201906). Written informed consent was obtained from each patient prior to any examination.

Results

The average near heterophoria was -8.0 (-15.3, -3.0)^△ at the initial examination, and it was reduced to -5.0 (-9.0, 0.0)^△ at the first review, showing significant difference (Z=-3.586, P<0.01). The mean accommodation amplitude of left and right eyes were 4.00 (3.25, 5.25)D and 4.00 (3.00, 5.00)D respectively before visual training, which were increased to 5.50 (4.25, 7.00)D and 5.00 (3.75, 7.00)D at the first review, showing significant differences (Z=-4.284, -3.995; both at P<0.01). The broken point and the recovery point of the long-distance positive fusion at the initial inspection were 7.5 (5.0, 15.8)^△ and 0.0 (0.0, 4.0)^△ respectively, which were increased to 11.0 (6.0, 22.0)^△ and 4.0 (0.0, 7.0)^△ respectively at the first review, showing significant differences (Z=-3.192, -3.748; both at P<0.01). The broken point and the recovery point of the near positive fusion at the initial inspection were 18.0 (8.0, 28.0)^△ and 6.0 (0.0, 12.0)^△, respectively, which were increased to 26.0 (21.5, 35.0)^△ and 11.5 (6.0, 16.0)^△ respectively at the first review, showing significant differences (Z=-4.695, -3.377; both at P<0.01). The monocular and binocular accommodation flexibility were increased from 2-3 cycles/minute at the initial examination to 10-12 cycles/minute at the first review, showing significant differences (all at P<0.01). Logistic regression analysis showed that age, distance heterophoria and near heterophoria were not related to the difference in accommodation improvement of the right and left eyes.At the initial examination, the average CISS score of 22 patients was (25.13±9.64) points, which was dropped to (19.18±7.22) points at the first review, showing significant difference (t=6.79, P<0.01). The 67.60% (48/71) of the patients who did not answer the questionnaire had obvious improvement in their main complaints and physical signs, and 29.58% (21/71) of them had improvement but still needed more training, and 2.82% (2/71) had no improvement in visual fatigue symptoms.

Conclusions

Systemic visual therapy can improve the visual function and alleviate symptoms majority of the adult patients with abnormal visual function, suggesting that adult visual function is still of strong plasticity.

Visual function; Asthenopia; Vision therapy; Vision plasticity; Adults