Effect of posterior capsular opacification removal on automated perimetry

Abstract

Purpose Although posterior capsular opacification (PCO) is a common phenomenon in a considerable number of ophthalmologic patients, no prospective controlled trials assessing its influence on automated perimetry exist. This technique continues as a standard in the diagnosis of glaucoma and neuroophthalmological diseases. The aim of the present report is to investigate the effect of PCO on automated visual field examination. Methods A total of 26 PCO affected eyes of 26 patients had Humphrey SITA standard (program 24-2) immediately before, and between 1 and 8 weeks after Neodymium : YAG capsulotomy. The effect of learning associated with repeated testing was controlled with automated perimetry before enrolment and visual fields of the fellow eye. Best-corrected visual acuity (BCVA), intraocular pressure (IOP), and global perimetric pre-and post-laser indices were compared using the Student's t-test for paired samples. Correlation and linear regression analyses were also performed. Results BCVA and mean deviation (MD) improved following capsulotomy. Pattern standard deviation (PSD), an indicator of localized defects in the field, also improved significantly when PCO was solved. Moreover, a strong association among BCVA, MD, and PSD was shown both prior to and after capsulotomy. Conclusion PCO is a heterogeneous mean opacity. This polymorphism may alter visual field results, and may even simulate the perimetric behaviour of other pathologies such as glaucoma. Consequently, the presence of PCO should be considered in the interpretation of any automated perimetry in pseudophakic patients. In addition, the values obtained before capsulotomy may partially predict the values obtained after capsulotomy.

Does Posterior Capsule Opacification Affect the Results of Diagnostic Technologies to Evaluate the Retina and the Optic Disc?

“…Several researchers have reported that MD improved after cataract surgery [ 11 – 13 ]. Similarly according to our results, amelioration of MD occurred after capsulotomy [ 14 ].…”

“…The effect that cataract has on automated perimetry has been well investigated [ 11 – 13 ]. Our research group completed a study in eyes of patients with PCO who underwent a white-on-white automated perimetry test (Humphrey SITA standard programme 24-2) immediately before Nd:YAG capsulotomy and between postsurgery weeks 1 and 8 [ 14 ]. The compared pre- and postlaser perimetric indices were mean defect (MD) and pattern standard deviation (PSD).…”

“…PCO translucent opacities apparently induce erratic light-scatter within the eye, which results in a combination of underilluminated retinal areas and in an increased PSD. Yet when these irregularities have been eliminated through capsulotomy, retinal illumination can be more uniform, so PSD lowers [ 14 ].…”

Negative dysphotopsia: The enigmatic penumbra

“…Posterior capsule opacification (PCO) also causes light scatter, which reduces retinal contrast and results in reduced retinal threshold sensitivity. 50 Anterior axial movement of the IOL from capsular bag contraction is also a possible explanation for the decreasing incidence over time because it could reduce the axial space behind the iris to 0.06 mm or less. However, it would also be associated with a myopic shift in the patient's refraction, which is extremely rare with contemporary Figure 15.…”

La opacificación capsular posterior: un factor a tener en cuenta en la valoración del nervio óptico

“…Por otro lado evidenciamos también que algunos campos previos a la capsulotomía presentaban defectos que simulaban escotomas arqueados. Una vez realizado el láser, dichos artefactos desaparecieron (7). A efectos prácticos, por tanto, se podría confundir en determinados casos un defecto campimétrico producido por una OCP con un defecto campimétrico glaucomatoso (falso positivo).…”