Convergence Measures Improve Most Drastically Within 1 Month of Therapy

Near-point of convergence (NPC) and near-positive fusional vergence (PFV) most drastically improve during the first 4 weeks of office-based vergence-accommodative therapy in children with symptomatic convergence insufficiency, according to research published in Ophthalmic & Physiological Optics. However, subsequent improvements may continue throughout a 16-week therapy duration.

Researchers assessed convergence measures from 205 children (mean age 10.8 years; 59.5% girls) with symptomatic convergence insufficiency who were randomly assigned to office-based vergence-accommodative therapy from the Convergence Insufficiency Treatment Trial-Attention and Reading Trial (CITT-ART; ClinicalTrials.gov Identifier: NCT02207517). Participants underwent NPC and PFV measurements at baseline and at follow-up visits conducted 4, 8, 12, and 16 weeks after initiating therapy. 

Participants experienced the quickest rate of NPC and PFV improvements during the first 4 weeks of therapy, according to the report, and these measures abated during the subsequent 12 weeks of the study. After the first 4 weeks, NPC and PFV were normal in 65.9% and 69.3% of participants, respectively. After 12 weeks, NPC, PFV, and convergence composite were within normal limits in 93.2%, 91.7% and 87.8% of participants, respectively. Normalization occurred in an additional 4.4%, 2.0% and 4.4% of these participants, respectively during the final 4 weeks of the study.

The study authors suggest that extending therapy may benefit patients who have not achieved adequate convergence measures after 12 months of vergence-accommodative therapy.

“While both NPC and PFV normalized after 4 weeks of therapy in half of the participants, there were continued smaller and slower incremental gains in both clinical measures throughout the subsequent 12 weeks of treatment, with some participants still making significant improvements and only attaining normal convergence function between 12 and 16 weeks of therapy,” according to the researchers. “These findings highlight the importance of monitoring therapy progress by measuring NPC and PFV after 4 weeks of therapy, and can also be used to inform clinical practice estimates of therapy duration.”

Study limitations include failure to consider patients’ symptoms or include children younger than 9 years.