Multifocal soft contact lenses to reduce asthenopic symptoms in myopic patients: Study

Asthenopic symptoms are very common around 46% of adults have been reported to experience asthenopia during or after working on a computer and 23% of schoolchildren have been reported to have asthenopic symptoms. A new study by Dr Alex C.H. Ong reported that use of multifocal soft contact lenses for a one month period was associated with reduced severity of asthenopic symptoms but had no changes in accomadative lag.

The study is published in The Journal of the British Contact Lens Association.

The objective of the study was to evaluate the efficacy of multifocal soft contact lenses to reduce asthenopic symptoms in myopes with accommodative lag.

The study included twenty-four myopic participants, aged 18–35 years, with mean spherical equivalent (MSE) of ≤ -0.75D, were recruited in a randomised, double-blind crossover study. All participants were existing contact lens wearer with near orthophoria or esophoria, presenting with subjective asthenopic symptoms at baseline [Convergence Insufficiency Symptom Survey (CISS) score ≥ 21] and a lag of accommodation ≥ +0.75 D. All participants were initially fitted with single vision contact lenses for a one month period. Participants were then randomly assigned 1:1 to wear low add or high add multifocal soft contact lenses for a further month. After this period, the groups were reversed. Data were collected at baseline and following one month's wear of each lens. Change in CISS score was evaluated as the primary outcome measure, while secondary outcome measures were changes in accommodative lag and heterophoria status.

The results of the study were found to be

• Baseline CISS score was (mean ± SD) 25.04 ± 4.58. Post-intervention scores were as follows: single vision: 24.46 ± 4.59, low add: 12.17 ± 6.89, high add: 13.71 ± 7.23.

• Both low add and high add multifocal soft contact lens wear was associated with an improvement in CISS score compared to baseline CISS and single vision (all p < 0.01).

• No significant difference was found between the CISS score for the baseline CISS and single vision (p = 1.00).

• No significant difference was found in lag of accommodation between lens conditions (all p > 0.05), however, there was an exophoric shift in near heterophoria between single vision and both multifocal contact lenses, low add: (mean difference 1.33 Δ, p = 0.02; high add: mean difference 1.23 Δ, p = 0.02) but not between habitual spectacle or any other modality (all p > 0.05).

Dr Ong and team concluded that "The use of multifocal soft contact lenses for a one-month period was associated with reduced severity of asthenopic symptoms in pre-presbyopic myopes with accommodative lag. Whilst improvement of symptoms does not appear to be mediated by a significant reduction in accommodative lag, changes in heterophoria may play a role in reducing asthenopic symptoms."

For further information: https://www.contactlensjournal.com/article/S1367-0484(21)00148-X/fulltext