Effect of inferior oblique muscle belly transposition on versions and vertical alignment in primary position

Surgical treatment of unilateral acquired superior oblique muscle palsy in adults by inferior oblique belly transposition: a retrospective analysis

PURPOSE

Evaluate and analyze the efficacy of inferior oblique belly transposition (IOBT) in treating adult patients with diplopia and small-angle hypertropia caused by mild to moderate inferior oblique overaction (IOOA) secondary to acquired superior oblique palsy (SOP).

METHODS

Nine adult patients with diplopia and small-angle hypertropia associated with mild to moderate IOOA secondary to unilateral acquired SOP were included in the current retrospective study. All patients received the IOBT procedure between February 2019 and May 2023 at The Second People's Hospital of Jinan and were followed up for more than 6 months after the surgery. During the procedure, the belly of the inferior oblique muscle was fixed to the sclera at 5 mm posterior to the temporal insertion of the inferior rectus muscle. The following indicators were reviewed pre- and post-surgery: the vertical deviation (VD) in the primary position and in the Bielschowsky test, the fovea disc angle (FDA) of the affected eye, changes in IOOA, and diplopia.

RESULTS

After IOBT, the VD in the primary position decreased from 7.22△ ± 1.72△ (range 4△-10△) to 1.22△ ± 1.30△ (range 0△-3△). The VD in the Bielschowsky test decreased from 13.00△ ± 1.80△ to 3.22△ ± 1.09△. The FDA decreased from 10.02° ± 3.34° to 6.26° ± 1.91°. The grade of IOOA was reduced from 2.00 (1.00, 2.00) to 0.00 (0.00, 1.00). All changes were statistically significant (P < 0.001 or P = 0.006). Diplopia was resolved completely for all patients.

CONCLUSIONS

IOBT can effectively treat adults with diplopia and small-angle hypertropia caused by mild to moderate IOOA secondary to acquired SOP.

Efficacy of inferior oblique belly transposition combined with inferior oblique recession for asymmetric inferior oblique overaction

OBJECTIVE

To evaluate the efficacy of inferior oblique belly transposition (IOBT) combined with inferior oblique (IO) recession in treating bilateral asymmetric inferior oblique overaction (IOOA).

METHODS

A retrospective review. The data of 14 patients who underwent IOBT on the mild side of IOOA and IO recession on the severe side for bilateral asymmetric IOOA were analyzed retrospectively. The main surgical results including the correction of IOOA, hypertropia, horizontal deviation, V pattern, and fovea-disc angle (FDA) were observed.

RESULTS

The IOBT corrected the preoperative grade (+1.86 ± 0.53) of the mild-side IOOA to a postoperative grade (+0.07 ± 0.27; p < 0.001), and the severe-side IOOA was corrected from a grade of +3.14 ± 0.53 to a postoperative grade of +0.14 ± 0.36 by the IO recession (p < 0.001). The vertical deviation at distance in the primary position was decreased from 8.43 ± 4.05 PD preoperatively to 1.21 ± 1.48 PD postoperatively (p < 0.001). The mean V pattern was 25.00 ± 11.62 PD preoperatively and 3.18 ± 2.18 PD postoperatively (p < 0.001). The mean preoperative FDA on the side where IOBT was performed was -10.47 ± 5.85 degrees, and the postoperative FDA was -7.82 ± 6.42 degrees (p = 0.023). The mean FDA on the side with IO recession was -11.05 ± 5.14 degrees before surgery and -6.09 ± 4.52 degrees after surgery (p = 0.001). The overall success rate was 71.4% (10 of 14).

CONCLUSIONS

IOBT combined with IO recession is effective and safe in eliminating hypertropia, V pattern, and extorsion with bilateral asymmetric IOOA.

Automated measurement of the disc-fovea angle based on DeepLabv3

Purpose

To assess the value of automatic disc-fovea angle (DFA) measurement using the DeepLabv3+ segmentation model.

Methods

A total of 682 normal fundus image datasets were collected from the Eye Hospital of Nanjing Medical University. The following parts of the images were labeled and subsequently reviewed by ophthalmologists: optic disc center, macular center, optic disc area, and virtual macular area. A total of 477 normal fundus images were used to train DeepLabv3+, U-Net, and PSPNet model, which were used to obtain the optic disc area and virtual macular area. Then, the coordinates of the optic disc center and macular center were obstained by using the minimum outer circle technique. Finally the DFA was calculated.

Results

In this study, 205 normal fundus images were used to test the model. The experimental results showed that the errors in automatic DFA measurement using DeepLabv3+, U-Net, and PSPNet segmentation models were 0.76°, 1.4°, and 2.12°, respectively. The mean intersection over union (MIoU), mean pixel accuracy (MPA), average error in the center of the optic disc, and average error in the center of the virtual macula obstained by using DeepLabv3+ model was 94.77%, 97.32%, 10.94 pixels, and 13.44 pixels, respectively. The automatic DFA measurement using DeepLabv3+ got the less error than the errors that using the other segmentation models. Therefore, the DeepLabv3+ segmentation model was finally chosen to measure DFA automatically.

Conclusions

The DeepLabv3+ segmentation model -based automatic segmentation techniques can produce accurate and rapid DFA measurements.