Effectiveness of Home-Based Therapy for Symptomatic Convergence Insufficiency

At enrollment, subjects will be prescribed 15 minutes/day of active home-based computer therapy for 5 days/week during the 12 week treatment phase. Active home-based computer therapy will be provided the Home Therapy System (HTS) computer software and will include both fusional vergence and accommodative therapy. Subjects will perform the computer therapy while wearing red/blue glasses and accommodative therapy will be performed using the HTS accommodative flippers. Please refer to the procedures manual for further details.

At enrollment, subjects will be prescribed 15 minutes/day (3 sessions of 5 minutes each) of near target push-ups (NTP) for 5 days/week during the 12-week treatment phase. An alphabet pencil will be used as the target and an index card placed in the background will provide physiological diplopia control. With the pencil positioned at arm's length directly between the subject's eyes, the subject will slowly bring the pencil toward his/her nose while focusing on the small letter on the pencil. When the subject is no longer able to maintain a single image of the pencil, he/she will slowly move the target away from the nose until the pencil becomes single again. This procedure will be repeated several times. Please refer to the procedures manual for further details.

At enrollment, subjects will be prescribed either 5 minutes/day (NTP group) or 15 minutes/day (Placebo group) of placebo home-based computer therapy for 5 days/week during the 12 week treatment phase. Placebo computer-based therapy will be provided by the Home Therapy System (HTS) computer software. The vergence procedures are similar to the active version, however, the tasks will be modified to ensure no demand on the vergence system and no accommodative therapy is included in the placebo version. Please refer to the procedures manual for further details.

Subjects will be prescribed 5 minutes/day of placebo yoked prism flipper therapy for 5 days/week during the 12 week treatment phase. This procedure utilizes a 4 pd base right/4 pd base left prism flipper and "Accommodative Hopping Cards". Subjects view the text on the card through the prisms at 40 cm, perform the appropriate task and then flip the prism flipper to the other side after each word before proceeding to the next line. Please refer to the procedures manual for further details. The task remains constant, but the nature of the procedure changes with time: * Weeks 1-4: View the target through prism flippers * Weeks 5-8: Wear red-blue filter glasses while viewing the text through prism flippers * Weeks 9-12: Wear polaroid glasses while viewing the text through prism flippers