Capsular Block Syndrome
Postoperative capsular block syndrome (CBS) is caused by the intracapsular accumulation of liquefied material posterior to the nucleus or IOL and subsequent occlusion of the anterior capsulotomy. Early postoperative CBS may occur when residual OVD becomes trapped within the capsular bag, between the posterior capsule and the posterior surface of the IOL, causing a myopic shift in the refractive error from anterior displacement of the lens optic. Anterior displacement of the iris diaphragm with shallowing of the anterior chamber may also occur, which must be differentiated from a ciliary block mechanism. If left untreated, CBS may lead to posterior synechiae and secondary glaucoma. Nd:YAG laser anterior capsulotomy peripheral to the optic or posterior capsulotomy releases the trapped fluid, with resultant posterior movement of the IOL optic to its intended position, deepening of the anterior chamber, and resolution of the myopic shift.
Late postoperative CBS may occur years after surgery with the accumulation of a turbid or milky fluid between the posterior capsule and the IOL that is consistent with the by-products of trapped, residual lens epithelial cells (Fig 11-12). Myopic shift is uncommon in these cases, and the patient may be asymptomatic. Nd:YAG laser posterior capsulotomy usually resolves this condition without complications.
Figure 11-10 Illustration of intrascleral flanged haptic IOL fixation (Yamane technique). A, Transconjunctival scleral tunnels (180° apart) are made parallel to the limbus 2 mm posterior to the limbus with thin-walled (wide-bore) 30-gauge needles. Each tunnel is approximately 2 mm long. B, The needles are turned perpendicular (arrow) to the limbus to enter the eye. C, The leading haptic of a 3-piece foldable IOL is guided into the bore of the needle with microforceps under direct visualization. The same is done for the trailing haptic, and both are simultaneously externalized where noncontact thermal cautery is used to create a flange prior to replacement into the sclera (not shown; see Video 11-4).
(Illustration courtesy of Mark Miller.)
Ab externo flanged-haptic IOL fixation, Yamane technique. Courtesy of Charles Cole, MD.
Double-needle intrascleral flanged haptic IOL fixation, Yamane technique. Courtesy of Wesley Green, MD, and Arsham Sheybani, MD.
Ab externo IOL reposition with Hoffman pockets. Courtesy of Jason Leng, MD.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.