Identification of the source of permanent glare from a three-piece IOL

The Effect of Age, Postoperative Refraction, and Pre- and Postoperative Pupil Size on Halo Size and Intensity in Eyes Implanted with a Trifocal or Extended Depth-of-Focus Lens

Purpose

Halos are a chief source of patient dissatisfaction after multifocal intraocular lens (IOL) implantation. The primary purpose of this study was to investigate the influence of age, postoperative refraction, and pre- and postoperative pupil size on postoperative halo size with a trifocal diffractive IOL (AcrySof IQ PanOptix) and extended depth-of-focus (EDOF) IOL (TECNIS Symfony) to determine whether these factors could predict postoperative halo size.

Patients and Methods

This single-center, open-label study conducted between October 2018 and April 2020 in Yokosuka, Japan included 160 patients: 80 with PanOptix and 80 with Symfony IOLs. Size and intensity of the halos were examined binocularly using a computer-based simulator (Eyeland Design Network GmbH) and scored from 0 (minimum) to 10 (maximum) at 1, 3, and 6 months postoperatively, along with the change in each variable for both IOLs. The respective correlations of halo size with age, postoperative refraction, pre- and postoperative pupil size, and discomfort level due to the halo were also investigated 6 months postoperatively.

Results

Halo size and intensity were significantly mitigated between 1, 3, and 6 months postoperatively. Throughout the observation period, halo size was significantly larger with PanOptix than with Symphony (P < 0.05), and halo intensity was significantly higher with Symphony than with PanOptix (P < 0.05). The pre- and postoperative pupil size correlated positively with halo size, while age and postoperative refraction were negatively correlated, for both IOLs.

Conclusion

Understanding the features and predictive preoperative factors of halos in different types of multifocal IOLs may be useful in improving patient satisfaction.

Experimental and analytical quantification of light scattering from vacuoles in intraocular lenses

PURPOSE

To develop an advanced test methodology for quantification of scattered light from intraocular lenses (IOLs) and to evaluate the correlation between IOL vacuole characteristics and measured scattered light.

SETTING

U.S. Food and Drug Administration, Optical Therapeutics and Medical Nanophotonics Laboratory, Silver Spring, Maryland, USA.

DESIGN

Experimental and analytical study.

METHODS

Twenty-four IOLs containing vacuoles were evaluated using a digital microscopy approach for identifying and characterizing the vacuoles present. A scanning light scattering profiler (SLSP) was used to evaluate and quantify the amount of scattered light from each IOL and from a 25th control IOL without any vacuoles. A variety of IOLs and vacuoles were also modeled in a Zemax simulation of the SLSP, and the simulated scattered light was modeled.

RESULTS

The scattered light as measured with SLSP was well correlated with vacuole characteristics, specifically density and size, as measured under the digital microscope for the 24 vacuole-containing IOLs. Additional correlations were found between vacuole sizes, orientations, and the angle at which light was scattered most severely. These correlations were also present in the Zemax model.

CONCLUSIONS

Vacuole optical characteristics can be well correlated with measured scatter, demonstrating an ability to predict scattered light based solely on microscope evaluation. Furthermore, the quantitative amount of scatter predicted with Zemax simulations trended closely with the experimentally measured trends.

The impact on vision of aspheric to spherical monofocal intraocular lenses in cataract surgery: a systematic review with meta-analysis

PURPOSE

To provide a summary of the impact on vision of an aspheric intraocular lens (IOL) compared with a spherical IOL in cataract surgery.

DESIGN

Systematic review with meta-analysis.

PARTICIPANTS

Patients from published randomized controlled trials (RCTs) of cataract surgery with aspheric compared with spherical monofocal IOL implantation.

METHODS

We systematically searched the peer-reviewed literature in MEDLINE, EMBASE, Web of Science, BIOSIS, and the Cochrane Library according to the Cochrane Collaboration method to identify relevant RCTs. The inclusion criteria were RCTs on cataract surgery comparing the use of aspheric versus spherical IOL implantation that assessed visual acuity, contrast sensitivity, or quality of vision. The effects were calculated as mean differences or standardized mean differences (Hedges' g) and pooled using random-effect models.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA), contrast sensitivity, and subjective perception of the quality of vision.

RESULTS

Forty-three studies provided data and were included, comprising 2076 eyes implanted with aspheric IOLs and 2034 eyes implanted with spherical IOLs. The BCVA showed a significant difference for aspheric IOLs (-0.01 logarithm of the minimum angle of resolution; 95% confidence interval [CI], -0.02 to -0.00). For contrast sensitivity, a significant advantage for aspheric IOLs was found under photopic and mesopic light conditions (photopic: Hedges' g 0.42, 95% CI 0.24-0.61 (3 cycles per degree [cpd]) to 0.53, 95% CI 0.33-0.73 (12 cpd); mesopic: Hedges' g 0.49, 95% CI 0.23-0.75 (1.5 cpd) to 0.76, 95% CI 0.52-1.00 (18 cpd)). Questionnaires targeting the subjective perception of quality of vision yielded less conclusive results.

CONCLUSIONS

Overall, a patient may achieve better contrast sensitivity with an aspheric IOL than with a spherical IOL, especially under dim light. There was no clinically relevant difference in BCVA between aspheric and spherical IOL implantation. The findings on the subjective perception of visual quality were heterogeneous with no clear result favoring either option.

Single pass, single suture technique for repair of traumatic mydriasis

PURPOSE

We describe a 52-year-old man with pseudophakia and traumatic mydriasis who presented with severe glare.

METHODS

A modification of the Siepser sliding knot technique-single pass, single suture technique-allows the surgeon to create a locking knot at the extraocular space while maintaining a closed chamber, a safer and easier method for traumatic mydriasis repair.

RESULTS

A reduction of pupil size from 8.0×7.8 mm to 5.5 mm was noted. The patient's complaint of glare was relieved and the glare acuity was 20/40 at 6 months follow-up.

CONCLUSIONS

We present a new, simpler application of the Siepser slipknot which can be used successfully for repair of traumatic mydriasis.

Protective effects of taurine against alloxan-induced diabetic cataracts and refraction changes in New Zealand White rabbits

The present study examined the protective effects of taurine on alloxan-induced diabetic cataracts and lens damage in male New Zealand White rabbits. The animals were randomly divided into three treatment groups: (1) normal control (vehicle administration); (2) diabetes (100 mg/kg alloxan administration); and (3) diabetes + taurine (1% [w/v] taurine dissolved in drinking water and alloxan administration). The results showed that alloxan-induced diabetes caused significant (p < 0.05) hyperglycemia, hyperopic refraction shifts, cataract formation and lens damage compared with the normal control group. In contrast, the administration of taurine for 24 weeks significantly ameliorated the alloxan-induced elevated levels of blood glucose, level of hyperopic refraction error shifts in the eyes and progression of diabetic cataract formation in the lens in rabbits. Moreover, histopathology showed that the taurine supplement reduced the incidence of lens lesions induced by hyperglycemia. Overall, the studies demonstrate that taurine exhibits potent protective effects against alloxan-induced diabetic cataracts and refraction changes in rabbits.

Characterizing reflections from intraocular lens implants

OBJECTIVE

To develop a test method for characterizing glare from intraocular lenses (IOLs) and to confirm a clinical finding that the haptic insertion in the optic of a three-piece IOL produces extraneous line images.

METHOD

The method consists of directing a collimated Gaussian laser beam to various parts of the IOL to be tested in a water-filled model eye. Reflected images produced in the retinal plane are photographed with a digital camera.

RESULTS

A test method was developed to characterize the source of glare images from IOLs. The test method developed was used to confirm a clinical finding that the haptic insertion in the optic of a three-piece IOL produces extraneous line images.

CONCLUSIONS

The method developed can be used to characterize and pin point the source of extraneous glare images from intraocular lens implants. The haptic insertion in the optic of a three-piece IOL has been identified as a source of line images.