Home vision therapy and prism prescription in presbyopic persons with convergence insufficiency: study protocol for a randomized controlled trial.

BACKGROUND: Convergence insufficiency is a common issue in the field of binocular vision. Various treatment options have been suggested for managing this condition, but their efficacy in individuals with presbyopia remains unclear. The objective of this study is to compare the effectiveness of home-based vision therapy and prism prescription, in presbyopic patients with convergence insufficiency. METHODS/DESIGN: It is a randomized, prospective, double-blind clinical trial, with total of 150 participants randomly assigned to the three groups. The Control Group will receive a new near glasses as a conventional prescription, along with aimless and random eye movement exercises that do not have any convergence or accommodation effects. The Home Vision Therapy Group will receive new near glasses with accommodative and convergence eye exercises. The Prism Group will receive a near prismatic glasses prescribed using the Sheard's criterion. All treatments will be administered for a period of 2 months, and measurements of the modified convergence insufficiency symptoms survey (CISS), near point convergence, near phoria, and positive fusional vergence will be taken at baseline, one month later, and at the end of the treatment. DISCUSSION: We aim to identify which component - either the prism prescription or the home vision therapy - is more effective in improving binocular abilities and reducing patients' symptom scores. TRIAL REGISTRATION: ClinicalTrials.gov NCT05311917 with last update on 04/22/2023.

Fundus torsion following inferior oblique muscle weakening.

PURPOSE: To determine the postoperative fundus torsion following surgical inferior oblique (IO) weakening in patients with inferior oblique overaction (IOOA). METHODS: In this interventional case series, 37 patients with IOOA ≥ +1 and reliable preoperative fundus photographs were included. IO weakening was accomplished through myectomy or anterior transposition. Fundus photography was repeated at 3 months' follow-up. The primary outcome was change of disk foveal angle (DFA), measured as the angle between the line connecting the center of the fovea and optic disk and horizontal. Success or normal fundus torsion was defined as a postoperative angle of 0° to 8° of extorsion. Residual extorsion was defined as postoperative extorsion of > 8°. Postoperative intorsion was defined as any amount of induced intorsion. RESULTS: Mean age of patients (56% females) was 6.46 ± 6.79 years. At follow-up at least 3 months after surgery, the mean change of DFA was 7.79 ± 6.24° of reduction of extorsion after IO myectomy (P < 0.001) and 6.05 ± 6.07° after IO anterior transposition (P = 0.005). Normal fundus torsion was achieved in 50% of patients after myectomy and 36.4% of patients after anterior transposition. Residual extorsion was observed in 49% of patients; induced intorsion in 5%. CONCLUSIONS: Using objective measurement of fundus photographs, fundus extorsion was decreased in 94.7% of patients after myectomy or anterior transposition.