(Author Abstract): Amblyopia is the leading treatable cause of vision loss in childhood, with a prevalence of 2-5%. It is responsive to treatment early in life, but delayed treatment can result in life-long visual impairment. Unfortunately, health care practitioners are often unable to identify amblyopia risk factors, including strabismus, media opacities, and anisometropia, in patients under age 5, so that many cases of amblyopia go undetected and untreated. There is a need for a more effective method of detecting amblyopia risk factors. The fovea of the eye is surrounded by a distinctive pattern of birefrefringent fibers that change the polarization state of transmitted light. Our laboratory has developed a specialized form of retinal birefringence scanning (RBS), in which a small spot of polarized fight is scanned in a circle on the retina, and the returning fight measured for changes in polarization. We have demonstrated that RBS accurately (+/- 1 deg) detects foveal fixation in real time, in unrestrained subjects (including infants and children), making it possible to study patients with amblyopia and young children at risk for developing amblyopia. RBS has been characterized in only a small number of subjects, however, and little is known about individual variability. We have also developed binocular RBS (BRBS), which detects fixation of both eyes simultaneously and hence detects interocular alignment.
The specific aims are to more fully characterize the RBS signal in normal and amblyopic subjects to enhance accuracy (hence sensitivity and specificity), and to screen normal and strabismic subjects using BRBS to identify amblyopia risk factors. BRBS may make it possible to screen infants and children automatically for the presence of amblyopia risk factors, including ocular misalignment, media opacity, and possibly refractive error, thereby facilitating early detection and treatment of this preventable form of blindness. The ability to screen for early, small deviations may help resolve conflicting findings on the efficacy of early amblyopia detection and treatment.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-VISB (03))
Program Officer
Oberdorfer, Michael
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Johns Hopkins University
Schools of Medicine
United States
Zip Code
Gramatikov, Boris I; Zalloum, Othman H Y; Wu, Yi Kai et al. (2007) Directional eye fixation sensor using birefringence-based foveal detection. Appl Opt 46:1809-18
Gramatikov, B I; Zalloum, O H Y; Wu, Y K et al. (2006) Birefringence-based eye fixation monitor with no moving parts. J Biomed Opt 11:34025
Nassif, Deborah S; Piskun, Nadya V; Hunter, David G (2006) The Pediatric Vision Screener III: detection of strabismus in children. Arch Ophthalmol 124:509-13
Nusz, Kevin J; Congdon, Nathan G; Ho, Tang et al. (2005) Rapid, objective detection of cataract-induced blur using a bull's eye photodetector. J Cataract Refract Surg 31:763-70
Hunter, David G; Nusz, Kevin J; Gandhi, Nainesh K et al. (2004) Automated detection of ocular focus. J Biomed Opt 9:1103-9
Hunter, David G; Nassif, Deborah S; Piskun, Nadya V et al. (2004) Pediatric Vision Screener 1: instrument design and operation. J Biomed Opt 9:1363-8
Nassif, Deborah S; Piskun, Nadya V; Gramatikov, Boris I et al. (2004) Pediatric Vision Screener 2: pilot study in adults. J Biomed Opt 9:1369-74