August 2008

 

CATARACT/ IOL

 

The ins & outs of combining surgeries


by Matt Young EyeWorld Contributing Editor 

 

 
Surgeon’s view of the initial partial graded tenotomy performed on a left inferior rectus, a procedure that has certain advantages in adult strabismus patients; some surgeons are combining strabismus and cataract surgery procedures Source: Albert W. Biglan, M.D.

Combined strabismus and cataract surgery is safe and effective, according to one study, but it is more or less effective depending on the individual. Researchers analyzed 50 patients in the study, some of whom developed strabismus before cataract (group 1, with a mean age of 47.8 years) and vice versa (group 2, with a mean age of 32.3 years). The study was published in the January-March 2008 issue of Strabismus. “The strabismus success appears to be better in group 2 than in group 1,” wrote lead study author Sujata Guha, M.D., Sankara Nethralaya, Vision Research Foundation, Chennai, India. “In group 1, binocular interaction probably had never developed due to long-standing strabismus, so that the motor alignment results were poor. In group 2, the patients had already developed binocularity (as the first event was the development of cataract, not strabismus), so that the motor alignment results were better.” On the other hand, visual success was better in group 1, in which cataract had not been longstanding. In group 1, 20/40 or better was achieved in 70.6% of patients. In group 2, that level of visual acuity was achieved in 57.6% of patients. The researchers maintained that results were good with combined surgery, and the order in which patients developed their problems (strabismus then cataract, or cataract then strabismus) likely impacted their success rates. “The results also suggest that nearly two-thirds of all eyes that had combined strabismus and cataract surgery achieved surgical success after one operation,” Dr. Guha wrote.

Further considerations

Dr. Guha noted additional information important to consider. When the angle of deviation was more than 80 prism diopters, the strabismus success rate in group 1 was poor (25.0%), while in similar circumstances in group 2, the success rate was still 66.7%. Hence, again, strabismus success was better in group 2 overall. In some instances, such as when intermittent divergent strabismus decompensates after unilateral cataract development, removing the cataract alone could resolve strabismus when there is a small angle of deviation. “But in patients with a large angle of deviation, removal of the cataract will not resolve the strabismus,” Dr. Guha reported. “One might argue that one should first remove the cataract, reassess the strabismus, and then perform strabismus surgery as a second procedure. However, in those clinical cases where the angle of deviation is large or strabismus surgery is a cosmetic consideration, it is logical to perform both procedures in a single sitting.” The advantages of this include hospitalization duration reduction and accelerated visual rehabilitation. Dr. Guha noted the following specific scenarios in which the combined procedure is warranted: Strabismus surgery with secondary IOL is appropriate in eyes with large-angle sensory strabismus that have undergone needling or cataract surgery without IOL or contact lens or amblyopia therapy.

Combination is an option in cases of childhood strabismus that develop cataract in adult life.

It’s an option in densely amblyopic eyes that were not treated for childhood cataract at the right time. Finally, the procedure can be considered when eyes develop decompensated intermittent divergent strabismus due to cataract. This report is a continuation of research that has probed combined strabismus and cataract procedures, as it appears relatively few such studies have been published. According to Dr. Guha, the first was reported in 1986 and was suggestive of the procedure’s safety. The second was in 1998, which noted good strabismus success but variable visual success. The third report included just three patient case studies, but was suggestive of visual acuity improvement and alignment of visual axes that resolved diplopia.

This study included a relatively large series of the combined surgery and suggested a positive outlook for the procedure. Mark Packer, M.D., clinical associate professor of ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, said he still prefers performing cataract surgery first. “I like to do that first and let it settle down,” Dr. Packer said. “The amount of accommodative convergence you see may change when you correct the patient optically. I would do cataract first and then re-measure the esotropia. It might be the same, but it might be different because of the different optical system in place.”

Editors’ note: Dr. Guha has no financial interests related to this study. Dr. Packer has no financial interests related to his comments.

Contact Information

Guha: +91-44-28271616, drsg@sankaranethralaya.org

Packer: 541-687-2110, mpacker@finemd.com

The ins & outs of combining surgeries The ins & outs of combining surgeries
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