The influence of posterior capsular opacification removal on anterior segment birefringence parameters as measured by scanning laser polarimetry

Nd:YAG Laser Capsulotomy: Efficacy and Outcomes Performed by Optometrists

SIGNIFICANCE

An increasing number of optometrists are performing Nd:YAG laser capsulotomy procedures; however, there is limited published information on the outcomes of these procedures.

PURPOSE

This study aimed to assess the efficacy and safety of capsulotomy procedures performed by optometrists.

METHODS

Subjects diagnosed with posterior capsule opacification causing reduced vision and subjective visual complaints were recruited for this study. A baseline examination was performed to ensure that the subjects met all the necessary criteria. The procedure was performed by a licensed doctor of optometry at six different clinics, and each subject was monitored for visual outcome and any potential complications.

RESULTS

Subjects' Snellen visual acuity improved from an average of 20/40 to 20/23 ( P < .001) with no complications of increased intraocular pressure, inflammation, visually significant lens pitting, macular edema, or retinal detachment. Of 78 subjects who responded to a post-procedure survey, 77 (99%) reported subjective improvement in vision after capsulotomy.

CONCLUSIONS

Based on the outcomes of this study, YAG laser capsulotomies are effective treatments to improve patient vision that can be safely and effectively performed by optometrists.

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

The visual outcome obtained after cataract removal may progressively decline because of posterior capsular opacification (PCO). This condition can be treated by creating an opening in the posterior lens capsule by Nd:YAG laser capsulotomy. PCO optical imperfections cause several light reflection, refraction, and diffraction phenomena, which may interfere with the functional and structural tests performed in different ocular locations for the diagnosis and follow-up of ocular disease, like macular and optic nerve diseases. Some parameters measured by visual field examinations, scanning laser polarimetry, and optical coherence tomography (OCT) have changed after PCO removal. Imaging quality also changes following capsulotomy. Consequently, the results of ancillary tests in pseudophakic eyes for studying ocular diseases like glaucoma or maculopathies should be correlated with other clinical examinations, for example, slit-lamp biomicroscopy or funduscopy. If PCO is clinically significant, a new baseline should be set for future comparisons following capsulotomy when using automated perimetry and scanning laser polarimetry. To perform OCT in the presence of PCO, reliable examinations (considering signal strength) apparently guarantee that measurements are not influenced by PCO.

Effects of posterior capsular opacification on the evaluation of retinal nerve fiber layer as measured by Stratus optical coherence tomography

OBJECTIVE

To evaluate the effects of posterior capsular opacification (PCO) and Nd:YAG laser capsulotomy on the evaluation of peripapillary retinal nerve fibre layer (RNFL) as measured by Stratus (Carl Zeiss Meditec, Dublin, CA) optical coherence tomography (OCT).

DESIGN

Prospective interventional case series.

PARTICIPANTS

We studied 98 eyes of 89 patients experiencing PCO.

METHODS

We performed a complete ophthalmologic examination and evaluation of RNFL as measured by Stratus OCT before and after Nd:YAG capsulotomy. The patients were classified on the basis of PCO score or signal strength (SS) obtained by prelaser OCT scans.

RESULTS

The preoperative and postoperative peripapillary RNFL thicknesses were 90.24 ± 15.9 μm and 98.27 ± 14.1 μm, respectively (p < 0.001). The mean preoperative SSs were 5.4 ± 1.6, and they improved to 9.5 ± 0.5 postoperatively (p < 0.001). Prelaser and postlaser RNFL thicknesses differed significantly in eyes with preoperative SSs less than 7 (p < 0.05). Also, in patients with preoperative PCO grades higher than 2, there were significant increases in RNFL thickness after laser capsulotomy (p < 0.05).

CONCLUSION

RNFL thickness measured by the Stratus OCT is affected by PCO. RFNL thickness may be underestimated in eyes with preoperative PCO grades higher than 2 and in eyes with preoperative SSs lower than 7.

Effect of cataract surgery on retinal nerve fiber layer thickness parameters using scanning laser polarimetry (GDxVCC)

Purpose:

To study the effect of cataract extraction on the retinal nerve fiber layer (RNFL) thickness, and assessment by scanning laser polarimetry (SLP), with variable corneal compensation (GDx VCC), at the glaucoma service of a tertiary care center in North India.

Materials and Methods:

Thirty-two eyes of 32 subjects were enrolled in the study. The subjects underwent RNFL analysis by SLP (GDx VCC) before undergoing phacoemulsification cataract extraction with intraocular lens (IOL) implantation (Acrysof SA 60 AT) four weeks following cataract surgery. The RNFL thickness parameters evaluated both before and after surgery included temporal, superior, nasal, inferior, temporal (TSNIT) average, superior average, inferior average, and nerve fiber index (NFI).

Results:

The mean age of subjects was 57.6 ± 11.7 years (18 males, 14 females). Mean TSNIT average thickness (μm) pre- and post-cataract surgery was 49.2 ± 14.1 and 56.5 ± 7.6 (P = 0.001). There was a statistically significant increase in RNFL thickness parameters (TSNIT average, superior average, and inferior average) and decrease in NFI post-cataract surgery as compared to the baseline values. Mean NFI pre- and post-cataract surgery was 41.3 ± 15.3 and 21.6 ± 11.8 (P = 0.001).

Conclusions:

Measurement of RNFL thickness parameters by scanning laser polarimetry is significantly altered following cataract surgery. Post the cataract surgery, a new baseline needs to be established for assessing the longitudinal follow-up of a glaucoma patient. The presence of cataract may lead to an underestimation of the RNFL thickness, and this should be taken into account when analyzing progression in a glaucoma patient.