Main

Sir,

Capsular block syndrome is a known early and late complication of continuous curvilinear capsulorhexis (CCC).1 It occurs when fluid accumulates in the capsular bag secondary to occlusion of the anterior capsule by the intraocular lens optic.2 We report a case of capsular block syndrome discovered after Nd:YAG laser capsulotomy.

Case report

A 53-year-old man underwent uneventful phacoemulsification with CCC. A single piece 22.5 D PMMA lens with a 13.5 mm length and 5.5 mm optic lens was implanted. Postoperatively, his visual acuity improved from 6/24 (unaided) to 6/9 with −1.75 D spherical correction.

After 8 weeks, he had visual acuity of 6/60 due to a very dense chalky white thickening of the posterior capsule. A posterior capsulotomy was performed (energy 32 mj). On review 3 weeks later, visual acuity did not improve beyond 6/12 even with best correction. Detailed examination showed the thickened anterior capsule that was adherent to the anterior surface of the IOL and ‘chalky white’ remnants were seen on the periphery of the posterior surface of the implant. There was a clear space behind the implant and a posteriorly bowed capsule was seen far behind the implant. Also white debris was noted in the lower part of the space behind the implant. A capsular block syndrome was suspected. Subsequently a ‘true’ posterior capsulotomy was performed at the centre of the capsule, resulting in rapid movement of viscous fluid and debris into the vitreous, thus confirming the diagnosis. There was subsequent wrinkling of the large posterior capsule associated with backward displacement of the optic lens. At 2 weeks following capsulotomy, his visual acuity improved to 6/5 with −0.50 D spherical correction.

Discussion

Capsular block syndrome is a rare complication that is associated with an intact Continuous curvilinear capsulorhexis and it is important to recognise it particularly when the patient is myopic postoperatively and there is displacement of posterior capsule far behind the optic of the implant.3

Fibrotic reaction and larger optic lens in the bag favours formation of adherence between the lens and the capsule resulting in sealing of the capsulorhexis.2 Miyake postulated that this syndrome may result from osmotic attraction of the fluid due to various types of collagen and substances produced by the proliferating (Figure 1) lens epithelial cells (LEC).4 The resulting increase in space between the optic lens and the posterior capsule favours proliferation of LEC with this syndrome leading to dense thickening as in our patient. This case would be classified as late-onset capsular block syndrome according to the classification suggested by Miyake et al.5 Well known signs of this syndrome such as myopia due to anterior displacement of the implant,3, 6 shallow anterior chamber and capsular bag distension were resolved after second posterior capsulotomy.

Figure 1
figure 1

Showing the chalky white LEC behind the initial capsulotomy.

Full size image

Late-onset capsular block syndrome should be suspected even after posterior capsulotomy particularly when the anterior chamber is shallow and the patient is myopic. Thick growth of the LEC along the posterior surface of the implant mimicked and masked the view of the posterior capsule in our patient. Also the point of importance of this report is that careful detailed anterior segment examination with well-dilated pupil after laser procedure is required to ensure that an adequate capsulotomy has actually been performed.