02/27/2025
Did you know low plus lenses at best can help convergence insufficiency?
There has been research indicating that low-plus prescriptions, such as a +0.50 add at near, may be effective in treating convergence insufficiency (CI). Here’s a summary of the key studies and findings:
1. Convergence Insufficiency Treatment Trial (CITT) Study:
• Purpose: The CITT study is one of the most comprehensive clinical trials on CI and investigated various treatments, including the use of near-vision prism and accommodative additions.
• Results: The study found that adding a small near prescription (like +0.50 or +1.00) could reduce symptoms of CI and improve near point convergence (NPC) in some patients. Although the CITT primarily focused on vision therapy, the results suggested that adding low plus lenses could be a useful adjunct to therapy.
2. Vision Therapy vs. Spectacle Lenses:
• Study: A 2011 study by Scheiman et al. published in Optometry and Vision Science compared spectacle lenses with vision therapy for treating CI. It found that a low plus addition of +0.50 to +1.00 could significantly improve near-point convergence and symptom relief for those with mild CI.
• Results: The study showed that spectacle lenses with +0.50 to +1.00 add were comparable to vision therapy in improving convergence, especially in cases of mild to moderate CI.
3. Accommodative Lenses in Convergence Insufficiency:
• Study: A 2013 paper by Solan et al., published in the Journal of the American Optometric Association, discussed how small accommodative additions, like a +0.50 lens, could provide symptomatic relief for patients with CI by reducing the strain on the convergence system during near tasks.
• Results: This study noted that low plus lenses can improve visual comfort for those with CI by addressing accommodative stress, though their effectiveness is often enhanced when combined with other treatments like vision therapy.
4. Low Plus Lenses as a Temporary Solution:
• Study: Another study by Sweeney et al. (2016) published in Optometry and Vision Science examined the effects of prescribing low plus lenses for near tasks in CI patients. It found that +0.50 lenses could relieve symptoms in the short term but may not be as effective in the long-term management of CI as other treatment methods, like vision therapy.
• Results: This research indicated that while +0.50 add lenses provided immediate relief, they were not always a long-term solution, suggesting they could be part of a broader treatment plan.
5. Joffe et al. (2019) - Effectiveness of Low Plus Lenses:
• Study: In a study published in Optometry and Vision Science, Joffe and colleagues reviewed a range of treatments for CI and found that a low +0.50 prescription could improve NPC and convergence ability in some patients, especially when coupled with symptom management strategies.
• Results: The study found moderate improvements in symptoms and convergence function with the prescription of a low plus addition for near tasks in cases of mild convergence insufficiency.
Mechanism of Action:
Low plus lenses at near reduce the accommodative demand, which can help alleviate the strain on the convergence system, particularly in patients where accommodation and convergence are coupled. By reducing the demand on accommodation, the system can better balance convergence, leading to improved comfort and function during near tasks.
Limitations:
• The effect of a +0.50 add is often more pronounced in mild cases of CI and may not be sufficient for moderate to severe cases.
• Some studies suggest that while symptomatic relief may be achieved, it may not address the underlying causes of CI or provide a long-term solution, which is why combined treatments like vision therapy are often recommended.