Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Mar-Apr;56(2):121-5.
doi: 10.4103/0301-4738.39116.

Evaluation of distance and near stereoacuity and fusional vergence in intermittent exotropia

Pradeep Sharma  1 , Rohit Saxena, Makarand Narvekar, Ritu Gadia, Vimla Menon
Affiliations

Evaluation of distance and near stereoacuity and fusional vergence in intermittent exotropia

Pradeep Sharma et al. Indian J Ophthalmol. 2008 Mar-Apr.

Abstract

Aim: To evaluate the role of distance and near stereoacuity and fusional vergence in patients with intermittent exotropia [X(T)] and their change after surgery.

Materials and methods: This prospective interventional institution-based clinical study included 31 cases of X(T) requiring surgery and 33 age, sex-matched controls. All subjects underwent complete orthoptic assessment including near stereopsis (Randot stereogram) and distance stereopsis by polaroid stereo-projector apparatus using special paired slides and fusional vergence assessment at distance and near prism bar at baseline and one week, one month, three months and six months after surgery in X(T).

Results: The successful surgical alignment rate was 74.2%. Preoperatively, cases demonstrated significantly poor distance and near stereoacuity, compared to controls ( P < 0.001). Mean distance stereoacuity (sec of arc) in normals, (X)T preoperatively and postoperatively was 344.8 +/- 139.5, 1149.2 +/- 789.4 and 450.1 +/- 259 while mean near stereoacuity was 34.7 +/- 9.5, 68.7 +/- 31.1 and 47.4 +/- 22.6 respectively. Postoperatively at six months, significant improvement in stereoacuity was observed both at near and distance ( P < 0.05). Mean distance fusional convergence (in prism diopter) in normals, X(T) preoperatively and postoperatively was 20.7 +/- 4.7, 18.0 +/- 3.3 and 21.4 +/- 3.6 respectively, mean near fusional convergence was 27.8 +/- 6.3, 24.1 +/- 5.5 and 29.1 +/- 5.5 respectively. There was good correlation between fusional vergence amplitudes for distance and near indicating any one would suffice.

Conclusion: Early detection of abnormal stereoacuity (near and if possible distance) and near fusional vergence amplitudes may help to decide proper timing of surgery in X(T).

PubMed Disclaimer

Figures

Figure 1
Figure 1
Photo of stereoprojector used in this study
Figure 2
Figure 2
a and b: Photo of stereoprojector paired slides. The disparity (in mm) between the two similar images governs the extent of stereopsis measured. The stereopsis levels measured by the paired slides are given
See this image and copyright information in PMC

Comment in

References

    1. Hutchinson AK. Intermittent exotropia. Ophthalmol Clin North Am. 2001;14:399–406. - PubMed
    1. Von Noorden GK. Binocular Vision and Ocular Motility. 5th ed. St Louis: Mosby Year Book; 1996. pp. 341–59.
    1. Rutstein RP, Corliss DA. The clinical course of intermittent exotropia. Optom Vis Sci. 2003;80:644–9. - PubMed
    1. Jampolsky A. Differential diagnostic characteristics of intermittent exotropia and true exophoria. Am Orthopt J. 1954;4:48–55. - PubMed
    1. Hiles DA, Davies GT, Costenbader FD. Long term observations on unoperated intermittent exotropia. Arch Ophthalmol. 1968;80:436–42. - PubMed