To compare horizontal strabismus deviation as assessed from photographs with that in the strabismus clinic using the prism bar.

Publisher: Medknow Publications Country of Publication: India NLM ID: 0405376 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1998-3689 (Electronic) Linking ISSN: 03014738 NLM ISO Abbreviation: Indian J Ophthalmol Subsets: MEDLINE

Publication: Mumbai : Medknow Publications
Original Publication: Bombay : All-India Ophthalmological Society

Strabismus*/diagnosis ; Strabismus*/physiopathology ; Photography*/methods ; Oculomotor Muscles*/physiopathology; Humans ; Male ; Female ; Adult ; Child ; Adolescent ; Young Adult ; Child, Preschool ; Vision, Binocular/physiology ; Eye Movements/physiology ; Reproducibility of Results

Purpose: To compare the deviation in cases of horizontal strabismus as assessed from photographs with the measurements as obtained in the strabismus clinic.
Methods: After obtaining informed consent, we recruited subjects with manifest horizontal strabismus. We took a frontal flash photograph from a distance of 50 cm using smart-phone-based cameras with the flash light vertically aligned with the lens. After projecting the photograph on a laptop and using a vernier caliper, we measured the horizontal corneal diameter of the non-strabismic eye and the decentration of reflex in the strabismic eye taking limbus as the reference point. We converted these values to degrees by using a conversion factor of 7.5°/mm and further to prism diopters (PD) by the standard mathematical formula 100*tanθ.
Results: We included 74 subjects aged between 5 and 40 years with manifest horizontal deviation from 20 to 85 PD. We found a statistically significant correlation of 82.6% (P value < 0.001) between the clinic and photographic measurements. Agreement analysis suggested that the photographic measurements measured on average 7 PD less (95% confidence interval: 4.6 to 9.2) than clinical measurements along all values of misalignment, although the difference between the two methods decreased as the quantum of deviation increased. Linear regression revealed an r2 of 68% and provided a predictive equation to derive clinic equivalent measurements from photographic estimates.
Conclusion: We believe our simple method provides robust evidence that a photographic estimation can provide the basic information of the size of the deviation to plan possible surgeries, especially in situations of a tele-consultation. This is an easy approach to both understand and master and should form the armamentarium of most orthopticians and strabismologists.
(Copyright © 2024 Copyright: © 2024 Indian Journal of Ophthalmology.)

Clin Pediatr (Phila). 1986 Jun;25(6):304-7. (PMID: 3698453)
Br J Ophthalmol. 2006 Jul;90(7):883-8. (PMID: 16782950)
J Med Assoc Thai. 2012 May;95(5):699-703. (PMID: 22994031)
Arq Bras Oftalmol. 2014 Aug;77(4):225-7. (PMID: 25410173)
Ophthalmology. 1998 Jul;105(7):1301-6. (PMID: 9663237)
Br J Ophthalmol. 2012 Jan;96(1):78-82. (PMID: 21984778)
J AAPOS. 2019 Feb;23(1):18.e1-18.e6. (PMID: 30682411)
PLoS One. 2021 Dec 1;16(12):e0258744. (PMID: 34851974)
Invest Ophthalmol Vis Sci. 2010 Jul;51(7):3411-7. (PMID: 20207979)
Invest Ophthalmol Vis Sci. 1992 Jan;33(1):234-46. (PMID: 1730544)
Invest Ophthalmol Vis Sci. 1987 Apr;28(4):736-42. (PMID: 3557878)
Control Clin Trials. 1998 Dec;19(6):589-601. (PMID: 9875838)
Arq Bras Oftalmol. 2014 Oct;77(5):275-279. (PMID: 25494370)
J Med Assoc Thai. 2015 Dec;98(12):1193-8. (PMID: 27004304)

Date Created: 20240730 Date Completed: 20240730 Latest Revision: 20241006

20241006

PMC11451785

10.4103/IJO.IJO_409_23

39078965