Transactions 29th European Strabismological Association Meeting – de Faber (ed) © 2005 European Strabismological Association, ISBN 04 1537 211 9

Dissociated Vertical Deviation and its relationship with time and type of surgery in infantile esotropia

Umut Arslan, Huban Atilla & Necile Erkam

Ankara University, School of Medicine, Department of Ophthalmology, Ankara, Turkey

ABSTRACT:

Purpose: To investigate the development of Dissociated Vertical Deviation (DVD) in infantile esotropia and its relationship with the age and the technique of the surgical intervention. Material and Method: Retrospectively records of 144 infantile esotropia cases that were followed in our clinic between the dates January 1991 – December 1997 were examined. Their ages at the time of admission, risk factors, ophthalmologic examinations before and after treatment and treatment mode were recorded and compared.

Results: DVD was found to develop in approximately half of the cases (47.9%) at an average age of 3.2 years (20 months–5.5 years) regardless of the treatment. DVD developed in 80.5% of cases that had no surgery and 37.5% of the cases that were treated surgically. When we compared according to the age, it was seen that 24.1% of the cases that were treated between ages 6 months and 2 years and 52% of the cases that were treated after 2 years of age had DVD and the difference was significant (p 0.01). In comparison to the surgical technique, DVD developed in 34.8% of the cases that had bimedial rectus recession and in 38% of the cases with unilateral recession and resection of rectus muscles without any significance (p 0.05).

Conclusion: As a result, the most efficient treatment mode in infantile esotropia is surgical intervention in early periods to obtain less DVD development as well as other established goals such as to obtain binocularity and prevent amblyopia. It is concluded that DVD development increases if surgery is not performed, if it is performed at later ages, and if additional muscle surgery is needed in time for undercorrection.

1INTRODUCTION

Dissociated Vertical Deviation (DVD) describes the condition in which either eye, or occasionally only one eye elevates when the amount of light is reduced, for example by an occluder during the cover test. The elevated eye returns to its original position when the cover is removed. It can become manifest spontaneously, often occuring when the patient is fatigued or daydreaming.

DVD is characterized by a slow drift of one eye up and out with slight extorsion. It is almost always bilateral, but often asymmetric. DVD can be distinguished from a true hypertropia by a lack of a corresponding contralateral hypotropia. DVD is an acquired condition that usually develops between the ages of 18 months and 3 years. It is rarely seen under 1 year of age but can occur as late as 5 or 6 years. It can be associated with all types of motility defects, including limited elevation, although infantile esotropia is the most common and often occurs after treatment of the horizontal deviation (1, 2).

The purpose of this study to investigate the development of DVD in infantile esotropia and its relationship with the age and the technique of the surgical intervention.

2MATERIAL AND METHOD

Retrospectively, records of 144 infantile esotropia cases that were followed in Ankara University Medicine Faculty Ophthalmology Department between January 1991–December 1997 were

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included in the study. Their ages at the time of admission, risk factors, visual acuity, anterior segment and fundus findings, cycloplegic refraction, deviation measurements with Krimsky and/or alternating prism-cover tests, eye movements, binocularity with Worth 4 dot and Titmus tests before and after treatment, treatment mode and treatment age were recorded and compared.

3RESULTS

When the entire data of the 144 cases with infantile esotropia was reviewed, the average age at the time of application for all the cases was 1.8 years (4 months–28 years). Seventy-five of the cases (52.1%) were girls, and 69 (47.9%) were boys. According to the results of retinoscopy with cycloplegia, 130 cases were emmetropic (90.2%), 4 cases were myopic (2.8%), 5 cases were hyperopic (3.5%), 3 cases were astigmatic over 1.5 D (2.1%), and 2 cases were anisometropic (1.4%). In 34 cases (23.6%) out of 144, family history was positive, there was history of hypoxia at birth in 7 cases (4.8%) and preterm labor history was present in 5 cases (3.5%) as risk factors to infantile esotropia.

While DVD was present in 69 of the cases out of 144 (47.9%), it was symmetrical in 12 cases (17.4%), and asymmetrical in 57 (82.3%). Overaction of the inferior oblique muscle associated DVD in 30 cases (43.4%).

As treatment mode, bimedial rectus recession was performed in 93 cases of infantile esotropia out of 144 (64.6%), followed by recession of the inferior oblique muscles in 13 cases because of the overaction of the inferior oblique muscles (13.9%), resection of the lateral rectus muscles because of residual esotropia in 7 cases (7.5%), and resection of lateral rectus muscles and recession of inferior oblique muscles in another 6 cases (6.4%). Single surgical intervention was considered sufficient in 67 cases (72.2%) and deviation under 20PD was obtained in these cases.

In 21 cases out of 144 (14.5%) recession of the medial rectus and resection of lateral rectus muscle was performed unilaterally, and in 15 cases (71.4%) necessity for recession of inferior oblique muscle occurred in the same session, or more frequently, in a later session.

In 30 cases out of 144 (20.9%), including the patients presenting in later ages, no surgical intervention was performed. In 11 cases (36.6%) deviation was under 20 PD and surgery was not performed. In 23 of the 30 cases, for whom no surgical intervention was performed, and in 6 of the cases for whom surgical intervention was performed, DVD developed before surgery; in other words, in 29 of the 36 cases that had not undergone surgery (80.5%) DVD developed.

In 40 cases out of 108 (37.5%) for whom surgical intervention was performed, DVD was found at a mean age of 3.2 years (min-max: 20 months–5.5 years) and after the surgery. While DVD was found in 23 cases out of 67 (34.8%), for whom recession of bilateral medial rectus muscles were performed, it was seen that DVD developed in 9 cases out of 13 (69.2%) requiring additional surgery. It was noted that DVD developed in 8 cases out of 21 (38%) that had unilateral surgery. There was no statistically significant difference between bilateral and unilateral surgery groups (p 0.05).

The age of the surgical intervention was 6 months–2 years in 59 of the 114 cases that had surgery, and in only 1 case DVD developed in this interval, and in the remaining 14 cases out of 58 (24.1%) DVD was found after the surgery. In 55 cases (48.3%) surgery was performed after 2 years of age and in 5 cases DVD developed in pre-operational period and in 26 cases (26/50–52%) DVD developed in post-operational period. Difference between early and late surgery was statistically significant (p 0.01).

In 32 cases out of 144 (22.2%) monoocular amblyopia was found, and in 112 cases there was no amblyopia. Binocularity was not present in 91.6% and 4 of these cases who were amblyopic (2.7%), and all of the 12 cases with binocularity were cases that had surgery performed during 6 months–2 years of age.

4DISCUSSION AND CONCLUSION

DVD ratios in infantile esotropia reported by Weakley et al. was 36% (3). We found in our study that DVD developed in approximately half of the cases (47.9%) in an average age of 3.2 years

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(20 months–5.5 years) in cases with infantile esotropia that were treated or not treated. It was observed that DVD developed in 80.5% of the cases with infantile esotropia, for whom surgical intervention was not performed, and in 37.5% of the cases that were treated surgically and this higher incidence is statistically significant in untreated group.

Zak et al. reported that in patients with infantile esotropia who initially underwent corrective surgery between 5 and 24 months of age, successful alignment of the eyes was associated with a higher prevalance of fusion and stereopsis and a lower prevalance of DVD (4). Neely et al. reported occurrence of DVD in almost all patients with surgically treated congenital esotropia, and its development was found to be unrelated to the timing of surgical intervention during the first 24 months of life (5). In our study, it was seen that in 24.1% of the cases that were treated with surgery between ages 6 months and 2 years DVD developed, on the other hand DVD developed in 52% of the cases that were treated after 2 years of age and the difference was significant (p 0.01). Late surgery was found to have higher risk for DVD development.

Tolun et al. (6), Altintas et al. (7), Vroman et al (8), and Bartley et al. (9) reported that when deviations smaller than 50 PD, bilateral medial rectus recession would be quicker, simpler, less traumatic, and leave the lateral rectus muscles unoperated for patients requiring a second surgery. In our study, when the surgical methods were compared, DVD was detected in 34.8% of the cases that had bimedial rectus recession, and in 38% of the cases that had unilateral recession of medial rectus muscle and resection of lateral rectus muscle and the difference was not statistically significant in terms of surgical method (p 0.05). However, in bilateral surgical interventions, it was observed that in 69.2% of the cases required additional surgical intervention in addition to recession of medial rectus muscles.

The most efficient treatment mode in infantile esotropia is surgical intervention in early periods to obtain less DVD development as well as other established goals such as obtaining binocularity and prevention of amblyopia. It is concluded that DVD development increases if surgery is not performed, if it is performed at later ages, or if additional muscle surgery is needed for undercorrection or overaction of inferior oblique muscle.

REFERENCES

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2.Wright KW. Complex strabismus and nystagmus. Strabismus Surgery 2000; 2nd edition-Chapter 6:41–2.

3.Weakley DR Jr. Parks MM. Results from 7-mm bilateral recessions of the medial rectus muscles for congenital esotropia. Ophthalmic Surg 1990;21(12):827–30.

4.Zak TA. Morin JD. Early surgery for infantile esotropia: results and influence of age upon results. Can J Ophthalmol 1982;17(5):213–8.

5.Neely DE. Helveston EM. Thuente DD. Plager DA. Relationship of dissociated vertical deviation and the timing of initial surgery for congenital esotropia. Ophthalmology 2001;108(3):487–90.

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