Is ultrasonography essential before surgery in eyes with advanced cataracts?

Background: Ultrasonography is an important tool for evaluating the posterior segment in eyes with opaque media.
Aim: To study the incidence of posterior segment pathology in eyes with advanced cataract and to see whether certain features could be used as predictors for an abnormal posterior segment on ultrasound. Setting: Tertiary care hospital in South India.
Methods and Materials: In this prospective study conducted over a 6-month period, all eyes with dense cataracts precluding visualization of fundus underwent assessment with ultrasound. Presence of certain patient and ocular "risk" factors believed to be associated with a higher incidence of abnormal posterior segment on ultrasound were looked for and the odds ratio (OR) for posterior segment pathology in these eyes was calculated.
Results: Of the 418 eyes assessed, 36 eyes (8.6%) had evidence of posterior segment pathology on ultrasound. Retinal detachment (17 eyes; 4.1%) was the most frequent abnormality detected. Among patient features, diabetes mellitus (OR= 4.9, P=0.003) and age below 50 years (OR= 15.4, P=0.001) were associated with a high incidence of abnormal ultrasound scans. In ocular features, posterior synechiae (OR= 20.2, P=0.000), iris coloboma (OR= 34.6, P=0.000), inaccurate projection of rays (OR= 15.1, P=0.002), elevated intraocular pressure (OR= 15.1, P=0.004), and keratic precipitates (OR= 22.4, P=0.004) were associated with high incidence of posterior segment pathology. Only four eyes (1.5%) without these features had abnormal posterior segment on ultrasonography.
Conclusions: Certain patient and ocular features are indicative of a high risk for posterior segment pathology and such patients should be evaluated by ultrasonography prior to cataract surgery. In the absence of these risk factors, the likelihood of detecting abnormalities on preoperative ultrasonography in eyes with advanced cataracts is miniscule.