Home Vision Therapy and Prism Prescription in Presbyopic Persons With Convergence Insufficiency

Plain-language summary

convergence insufficiency is one of the most common binocular vision problems in which the eyes tend to have more exophoria in near than distance activities. Its prevalence is typically reported from 2.25% to 29.6% depending on the study population and its definition. Most of its symptoms include difficulty seeing at close works, headache, eye pain during study, blurred vision, diplopia, movement of words in reading, a feeling of pressure in the eye, and lack of concentration. Its signs include increasing near point of convergence, more exophoria at near than distance, decreased AC / A ratio, decreased positive fusional vergence. In patients with convergent insufficiency, the first valid and standard questionnaire to assess the frequency and type of symptoms used before and after convergence insufficiency treatment is the convergence insufficiency symptom survey (CISS) questionnaire. Generally, vision therapy is the first choice for convergence insufficiency management and the other choice is base in prism prescription. On the other hand, due to the changes in the interaction of the accommodation and convergence systems with increasing age, It is necessary to study how these systems interact and compare their responses to the active treatment of vision therapy and inactive prescription of base in prism. In this controlled study, investigators will evaluate and compare the effect of vision therapy and base in prism prescription in patients over 40 years of age. this investigation will help to clarify which treatment is more effective. This study will have two phases. In the first phase, investigators will seek to check the reliability and validity of the Persian version of CISS questionnaire for the elderly patients. For this purpose, investigators will use the Persian version questionnaire in previous study that assessed for young adults, and the investigators will modify it and check the reliability and validity of the final Persian version for subjects with presbyopia. This modified CISS questionnaire will be investigated in the elderly participants and the appropriate cut off point to differentiate between the normal group and the group with convergence insufficiency will be determined. in the second phase one optometrist (Z.K.R) will do the preliminary examination and another optometrist (S.A) will do the interventions. After the initial examination and having the inclusion criteria, patients will be invited to participate in the study, the nature of the research will be explained to subjects and informed consent will be obtained from them. Before randomization, patients are asked to complete the CISS questionnaire and submit this questionnaire to Optometrist No. 1 (Z.K.R).According to the randomization all patients will be assigned to one of the treatment or control groups by optometrist No. 1. Vision therapy exercises, necessary trainings and prescriptions are given to all patients by Optometrist No. 2 (S.A).For the participants in the control group only near glasses will be prescribed as a conventional treatment, for the second group near glasses with base in prism according to sheard's criterion will be prescribed and in the third group, the prescription of near glasses will be given along with the complete training of the home exercises.

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