title: The effect of strabismus on object detection in the ring scotoma of a monocular bioptic telescope.
abstract: OBJECTIVE
  People with reduced visual acuity are permitted to drive with the aid of bioptic telescopes in the USA, the Netherlands, and Canada. When viewing through a monocular bioptic telescope, suppression of the deviating eye in strabismus may reduce the ability of the non-telescope eye to detect objects whose images fall in the ring scotoma area of the telescope eye, which could impair detection of traffic-relevant events. This ability to detect stimuli in the ring scotoma area was compared for strabismic and non-strabismic patients.
  
  
  METHODS
  Ten strabismic and six non-strabismic patients with bilaterally reduced visual acuity (0.30-1.0 logMAR, 6/12 to 6/60) participated. A dichoptic perimeter presented stimuli to the fellow (non telescope) eye in the area of the ring scotoma under binocular viewing. Fellow-eye detection rates were determined with and without a bioptic, on uniform and patterned backgrounds, while performing passive (viewing a cross) and active (reading letters) fixation tasks.
  
  
  RESULTS
  All strabismic patients were found to have anomalous retinal correspondence. Both non-strabismic and strabismic patients had lower fellow-eye detection rates on patterned than on uniform backgrounds, and while performing the active task. In addition, strabismic patients had lower detection with than without the bioptic on the patterned background. They also had a larger decrease in detection from the uniform to the patterned background than non-strabismic patients (26% vs 8%). Depending on the angle and direction of the deviation relative to the stimulus side, strabismus either increased or decreased fellow-eye stimulus eccentricity on the retina. Larger detection rate reductions between the uniform and patterned backgrounds were associated with more eccentric stimulus locations (ρ = 0.61, p = 0.013).
  
  
  CONCLUSIONS
  Both strabismic patients and non-strabismic patients were able to detect stimuli with the fellow eye in the ring scotoma area, demonstrating successful bi-ocular multiplexing. However, strabismic patients generally had a greater reduction in detection performance from the uniform to the patterned background than non-strabismic patients, which was accounted for in part by differences in stimulus eccentricities on the retina (that varied with the angle and direction of the strabismus). However, a study with a larger sample, including participants with strabismus and normal retinal correspondence, is needed before our findings can be generalized.
authors: Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA.
authors: Amy L
authors: AL
authors: Doherty
authors: Alex R
authors: AR
authors: Bowers
authors: Gang
authors: G
authors: Luo
authors: Eli
authors: E
authors: Peli
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001334:Automobile Driving; D005139:Eyeglasses; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013285:Strabismus / Q000503:physiopathology*; D061351:Telescopes; D015354:Vision, Low / Q000503:physiopathology / Q000534:rehabilitation*
references: Orphanet J Rare Dis. 2007 Nov 02;2:43
references: 17980020
references: Optom Vis Sci. 2000 Nov;77(11):573-81
references: 11138830
references: JAMA Ophthalmol. 2013 Mar;131(3):303-9
references: 23329309
references: Optom Vis Sci. 2001 May;78(5):304-15
references: 11384008
references: Arch Ophthalmol. 1974 Oct;92(4):273
references: 4412945
references: Surv Ophthalmol. 1985 Sep-Oct;30(2):75-101
references: 3934778
references: Trans Am Ophthalmol Soc. 1974;72:132-8
references: 4462239
references: Arch Ophthalmol. 2011 May;129(5):611-7
references: 21555615
references: Curr Opin Ophthalmol. 1999 Oct;10(5):320-6
references: 10621545
references: J Biomed Opt. 2010 Jan-Feb;15(1):016011
references: 20210457
references: Percept Psychophys. 1991 Jun;49(6):495-508
references: 1857623
references: J Vis. 2005 Dec 28;5(11):1004-12
references: 16441198
references: Invest Ophthalmol Vis Sci. 2011 Apr 08;52(5):2306-13
references: 21220551
references: Am J Optom Physiol Opt. 1978 Mar;55(3):208-13
references: 677263
references: AMA Arch Ophthalmol. 1955 Nov;54(5):683-96
references: 13258000
references: Invest Ophthalmol Vis Sci. 2005 Jan;46(1):66-74
references: 15623756
references: Optom Vis Sci. 2012 Sep;89(9):1249-56
references: 22863791
references: Optom Vis Sci. 1989 Jul;66(7):420-5
references: 2771327
references: J Vis. 2011 Jun 17;11(7):15
references: 21685401
references: Br J Ophthalmol. 1984 Mar;68(3):174-8
references: 6696870
references: Am J Ophthalmol. 2007 Aug;144(2):209-216
references: 17533108
references: J Am Optom Assoc. 1995 May;66(5):274-80
references: 7629367
references: Vis Neurosci. 1992 May;8(5):469-78
references: 1586647
references: J Opt Soc Am A. 1991 Nov;8(11):1762-74
references: 1744773
references: Doc Ophthalmol. 1967;23:346-98
references: 5583482
references: J AAPOS. 1997 Mar;1(1):16-9
references: 10530980
references: Perception. 1999;28(5):551-74
references: 10664754
references: Annu Rev Psychol. 2008;59:167-92
references: 17705683
references: Arch Ophthalmol. 1983 Dec;101(12):1907-8
references: 6651597