Treating Amblyopia with Liquid Crystal Glasses: A Pilot Study

Abstract

PURPOSE. To evaluate the use of liquid crystal glasses (LCG) for the treatment of amblyopia caused by refractive errors, strabismus, or both. METHODS. In this noncomparative, prospective, interventional case series, 28 children (age range, 4-7.8 years) with monocular amblyopia participated, of which 24 completed the study. In the LCG, the occluding and nonoccluding phases of the flicker were electronically set in all patients at a fixed rate. The rate was set so that accumulated occlusion was 5 hours during 8 hours' weartime. Occlusion was applied only to the good eye. All 24 children were followed up regularly for 9 months. Best corrected VA for distance and near, fixation patterns, and binocular function were measured. VA for distance was measured with the Snellen chart and for near with the Rossano/Weiss chart. RESULTS. Mean VA for distance at the end of the study (after 9 months) was 0.59 (SD, 0.16) compared with 0.27 (SD, 0.09) at the beginning (P < 0.001). Most of the children (92%) complied well with the treatment. (Good compliance was defined as wearing the LCG for at least 8 hours per day.) Stereopsis at the end of treatment was good (better than 60 sec arc) in 21% of the children compared with 8% at the beginning. No serious adverse events were recorded. CONCLUSIONS. The use of LCG in patients with amblyopia yielded an improvement in near and distance VA and in stereopsis. Treatment was well accepted by children and parents.

Does Partial Occlusion Promote Normal Binocular Function?

“…30 The use of ND filters has also been advocated as a means of balancing the vision in the two eyes of amblyopic observers to promote better stereopsis. 31,32 Thus, optical defocus, Bangerter distortion, or methods producing overall luminance reduction 33 could all provide potential alternatives to full occlusion and result in better binocular outcomes. The second aim of this study was to compare all three of these partial occlusion techniques in observers with normal binocular vision to determine which allows for the most robust binocular function while still reducing the acuity in one eye.…”

Using liquid crystal glasses to treat amblyopia in children

“…To our knowledge, only 2 studies investigating the effectiveness of these devices in the treatment of amblyopia have appeared. 9,10 These studies investigated the effectiveness of LCG in children with a mean age of approximately 6 years. The present study aimed to evaluate the effectiveness of LCG in the treatment of slightly older children with monocular amblyopia.…”

The Neurology of Amblyopia: A Further Evaluation of Data from the Eyetronix Flicker Glass Clinical Study

“…Looking more deeply into the level of penalization in that particular PEDIG study, patching was done two to six hours daily, or an average of four hours for a total of 24 weeks-an average of 672 hours of time the better eye was penalized. That actually pales in comparison to Spierer et al (2010) using their original 40 second/20 second liquid crystal penalization technique with a treatment time of 2160 hours over nine months, their protocol being 8 hours use per day during which the better eye was penalized roughly 5 hours per. In the Eyetronix Flicker Glass study, the devices were worn, on average, 1.5 hours a day for 12 weeks-an average of 126 treatment-hours, or less than 20% of the total PEDIG treatment time (6% of the Spierer et al treatment time).…”

“…We can shorten the patching time or we can lengthen it depending on response of the eye, but it is still penalization. We can even patch in 30-second intervals now (Pediatric eye disease investigator group, 2005;Spierer et al, 2010;Wang et al, 2015).…”