Experience with the CAM vision stimulator: preliminary report.

Abstract

SUMMARY Eighty-four children with at least 2 lines of amblyopia were treated with the CAM vision stimulator. 91 % of the children who had received no previous amblyopia therapy showed improvement, 73 % achieving 6/12 vision or better. Of children in whom previous occlusion therapy had failed 73 8 % improved. The treatment appears to be effective, rapid, and well tolerated. Our initial impressions have been sufficiently favourable to stimulate further clinical evaluation.Amblyopia probably affects between 4%1 and 7%2 of children in this country. Our understanding of the pathophysiology of amblyopia has blossomed over the last 20 years,3-5 yet the treatment has remained essentially unchanged since 1746..6 Occlusion continues to be the mainstay of treatment, and though it is recognised to be both psychologically and educationally disruptive, alternative methods have not as yet proved sufficiently effective to supplant it.' Recent reports of experience with a new, physiologically based, form of treatment have been encouraging.89 We report an independent, preliminary assessment of this treatment. Materials and methodsChildren attending the Orthoptic Departments of the Birmingham and Midland Eye Hospital and the Birmingham Childrens' Hospital were included in the study if they had 2 or more lines of amblyopiaas measured by linear optotypes-and were able to co-operate with treatment. All children had a full ophthalmological examination, and no child with anterior segment or fundus pathology commensurate with the visual acuity was included.All the children were refracted under cyclopentolate cycloplegia, and full optical correction was prescribed. When the spectacles had been worn for at least 1 week, treatment was started. Each child was shown a series of high-contrast square-wave gratings of different spatial frequencies, and treat- The children had a full orthoptic examination at the beginning and end of treatment, and the visual acuity was measured before and after each session. Four weeks after treatment had been discontinued the children had a further orthoptic examination.Between sessions the children received no additional treatment.

Treatment for amblyopia with rotating gratings and subsequent occlusion: a controlled study

“…The reasons for our failure to reproduce the excellent results of Campbell and coworkers (1, 3, 5, 23) are not obvious. The tremendous improvements reported by these authors were paralleled only by Willshaw et al (24), whereas all other groups trying the CAM-treatment were less successfull (6,7,8,10,11,12,13,14,15,21,22). It is conspicuous that all the studies which include control groups are in broad agreement with our conclusion that no specific efficacy can be attributed to grating patterns, and that the small improvements which were achieved are probably due to nonspecific training effects (7,10,14,15,21,22).…”

Active treatments for amblyopia: a review of the methods and evidence base

“…Preliminary findings showed improvements in amblyopic eye letter acuity and contrast sensitivity following one to 26 training sessions, and improvements were maintained four weeks after cessation of treatment. These findings were replicated by others using similar protocols 56,57 and these initial findings led to the suggestion that this method would offer a treatment for amblyopia that is not only effective but also rapid (in some cases, considerable improvements were recorded within two to three seven‐minute sessions).…”

Modified virtual reality technology for treatment of amblyopia

“…5 However, the authors are aware that the CAM stimulator was heralded as a novel and efficacious treatment modality based on initial case studies. 6,7 When a randomised controlled trial incorporated controls and a placebo treatment, visual acuity still increased. 8 Their conclusions were that rotating gratings were an insignificant variable in the treatment of amblyopia.…”