Influence of size of neodymium:yttrium-aluminium-garnet laser posterior capsulotomy on visual function

Abstract

Purpose The aim of this study was to examine the influence that the size of a neodymium:yttrium-aluminium-garnet (Nd:YAG) laser capsulotomy performed for posterior capsule opacification (PCO) has on visual acuity (VA), and on contrast VA and that in the presence of glare (glare VA). Methods A total of 41 consecutive eyes with PCO first underwent Nd:YAG laser capsulotomy of smaller than pupillary size, after which the capsulotomy was secondarily enlarged, 2 weeks later, to greater than pupillary size. Best-corrected VA, and contrast VA and glare VA under photopic and mesopic conditions were measured after the small and large capsulotomies were made. Results After enlargement, the mean capsulotomy area increased significantly from 4.8 to 15.3 mm 2 (Po0.0001). Best-corrected VA did not improve significantly after enlargement (P ¼ 0.1282). However, photopic contrast VA and glare VA at moderate to low contrast visual target before enlargement were significantly worse than those after enlargement (Pp0.0242); furthermore, mesopic contrast VA and glare VA improved significantly after enlargement (Pp0.0431). Conclusion Contrast VA and glare VA with a small capsulotomy were significantly worse than those with a large capsulotomy, which suggests that a capsulotomy larger than the pupillary size is necessary to restore contrast sensitivity and glare disability.

The influence of size and shape of Nd:YAG capsulotomy on visual acuity and refraction

“…The main goal of Nd:YAG laser capsulotomy is to increase visual acuity, however improving contrast sensitivity and decreasing disability due to glare are also important (9,10,12) . Smaller capsulotomy ope nings limit visual acuity by diffraction and result in light passing through the unopened region of the capsule being scattered causing glare and decreasing contrast sensitivity.…”

“…The overall incidence of posterior capsule opa cification (PCO) approaches 50% at 5 years following cataract sur gery (5)(6)(7) and disproportionately affects younger patients due to higher cell proliferation rates (8) . PCO decreases visual acuity and contrast sen sitivity leading to disability as a result of glare (9,10) . Nd:YAG laser capsulotomy has utility in the treatment of PCO; however, a number of complications of this procedure have been reported including IOL (11)(12)(13) .…”

Assessment of the Bag-in-the-Lens Implantation Technique in Diabetic Patients

“…The optic of the BIL implant is 5 mm in size. This may be compared with the apertures created by the Nd:YAG capsulotomy which range from 2.5 to 4.5 mm [15]. Although laser capsulotomy can clear the central visual axis, the small aperture can obscure the peripheral fundus precluding a full view of the retina for screening and therapeutic laser purposes.…”

“…However, the aperture in the posterior capsule created can vary from 2.5 to 4.5 mm [15], leaving opacification that may obscure the peripheral retina. Reduced peripheral retinal views may impair routine inspection in diabetic patients as well as hamper therapeutic pan-retinal laser photocoagulation (PRP).…”

Functional visual acuity after neodymium:YAG laser capsulotomy in patients with posterior capsule opacification and good visual acuity preoperatively

“…The evaluation of visual functional impairment in relation to the extent of the PCO can be performed using several different tests of visual performance, including psychophysical tests of visual acuity, contrast sensitivity, 10,11 glare testing, and forward light scatter combined with or without image-capturing video analysis. [12][13][14][15][16][17] A previous study 18 called functional visual acuity testing an important method of defining "detailed visual function".…”