Advances in lens implant technology

Stability of Intraocular Lens With Different Haptic Design: A Swept-Source Optical Coherence Tomography Study

Purpose: To investigate the stability of intraocular lens (IOLs) with different haptics by swept-source anterior-segment optical coherence tomography (AS-OCT).

Methods: Sixty-eight eyes from 55 patients received the implantation of Rayner 920H (Closed C-loop Group), Zeiss 509M (Plate Group) or Lenstec SOFTEC HD (C-loop Group) IOLs. The tilt and decentration of IOLs were evaluated using AS-OCT at least 1 month postoperatively.

Results: Mean decentration and tilt of IOLs were 0.18 ± 0.12 mm (range 0.02 to 0.59 mm) and 5.63 ± 1.65° (range 2.2 to 9.6°) respectively. Decentration was significantly smaller in the plate haptic group (0.12 ± 0.06 mm) as compared to the C-loop group (0.22 ± 0.13 mm, P = 0.02). The tilt of IOL was also significantly smaller in the plate haptic group (4.96 ± 0.89°) as compared to the C-loop group (6.28 ± 1.83°, P = 0.01). There was marginal difference between the Closed C-loop group (5.52 ± 1.74°) and C-loop group (6.28 ± 1.83°, P = 0.07).

Conclusions: The Plate-haptic IOLs should have better stability for the decentration and tilt than the C-loop design IOLs.

A Proposed Intervention to Decrease Resident-Performed Cataract Surgery Cancellation in a Tertiary Eye Care Center

BACKGROUND

Cataracts are the leading cause of preventable blindness globally. As a result, competence in cataract surgery is an important component of ophthalmology residency training. Residency programs must optimize the number of cataract surgery cases to train proficient physicians. However, the rate of cataract surgery cancellations is high, and some are canceled because of preventable causes.

OBJECTIVE

To evaluate the effect of mandatory on-site preadmission testing, including having a physical examination, on resident-performed cataract surgery cancellation rates.

METHODS

For this study, patients scheduled for cataract surgery at the Wills Eye Hospital resident cataract clinic between January 2015 and November 2015 were enrolled and randomized into 2 groups: usual care or intervention. The patients randomized to the usual care group were instructed to complete preadmission testing and to have a physical examination with their primary care physician. The patients randomized to the intervention group were escorted to a Wills Eye Hospital-affiliated cardiologist to complete preadmission testing and to have a physical examination. Patients in both groups received a reminder call before the cataract surgery.

RESULTS

A total of 441 patients were included in the study-240 patients in the usual care group and 201 patients in the intervention group. The overall cataract surgery cancellation rate was 14.5%; the rate was 12.4% in the intervention group and 16.3% in the usual care group (P = .28). The patients receiving the intervention were more likely to have preadmission testing and a physical examination than the patients in the usual care arm (P <.001).

CONCLUSIONS

Facilitating the completion of preadmission testing for patients decreased the rates of resident-performed cataract surgery cancellation at a Wills Eye Hospital resident clinic and has the potential to improve patient outcomes and prevent blindness.

Comparison of the Visual Performance After Implantation of Bifocal and Trifocal Intraocular Lenses Having an Identical Platform

PURPOSE

To compare the visual performance after bilateral implantation of a diffractive bifocal or trifocal intraocular lens (IOL) from the same manufacturer using the same IOL platform.

METHODS

This prospective, non-randomized, controlled study involved patients who had cataract surgery with bilateral implantation of bifocal or trifocal IOLs. The near, intermediate, and distance visual acuities, defocus curve, optical quality including modulation transfer functions and higher-order aberrations, National Eye Institute Visual Functioning Questionnaire-14, patient satisfaction, spectacle independence, and perception of visual disturbances were assessed in all patients.

RESULTS

Fifty eyes (25 patients) were implanted with a diffractive trifocal IOL (AT LISA tri 839MP; Carl Zeiss Meditec, Jena, Germany) and 60 eyes (30 patients) with a diffractive bifocal IOL (AT LISA 809M; Carl Zeiss Meditec). The follow-up was 3 months. No statistically significant difference was found in distance or near visual acuity between the two groups (P ≥ .05). Uncorrected, corrected, and distance-corrected intermediate visual acuities were significantly better in the trifocal IOL group (P < .01). In the binocular defocus curve, the visual acuity was also significantly better for defocus of -1.00 to -2.00 diopters in eyes with trifocal IOL implantation (P < .01). Similar halos and glare were present in the two groups. The levels of overall satisfaction were similarly high between groups.

CONCLUSIONS

Diffractive trifocal IOLs can provide significantly better intermediate vision and equivalent distance and near visual performance compared to bifocal IOLs and do not induce extra qualitative vision disturbances. [J Refract Surg. 2018;34(4):273-280.].

Prospective Clinical Comparison of Patient Outcomes Following Implantation of Trifocal or Bifocal Intraocular Lenses

PURPOSE

To compare the visual results and patient satisfaction after bilateral implantation between a bifocal and a trifocal intraocular lens (IOL).

METHODS

This study is a prospective, randomized, controlled study involving bilateral implantation of one of two multifocal IOLs. Patients were assessed for uncorrected and distance-corrected near (33 cm), intermediate (66 cm), and distance visual acuity. Distance contrast sensitivity under photopic (85 cd/m2) conditions with and without glare was also measured. Using a subjective questionnaire, patient satisfaction, spectacle independence, and the perception of glare and halo phenomena were evaluated at the final follow-up; a defocus curve analysis was conducted.

RESULTS

Fifteen patients (30 eyes) were implanted with the FineVision IOL (PhysIOL, Liége, Belgium) and 12 patients (24 eyes) received the Tecnis ZMB00 IOL (Abbott Medical Optics, Santa Ana, CA). The average follow-up was 6 months. The mean binocular uncorrected visual acuity was 0.02 ± 0.04 logMAR in the FineVision group and 0.04 ± 0.05 logMAR in the Tecnis group and the mean binocular uncorrected near visual acuity was 0.01 ± 0.00 logMAR in both groups. In the intermediate range of the defocus curve, there was a statistically significant difference between the two IOLs (P < .05). Contrast sensitivity was within normal limits under photopic conditions in both groups.

CONCLUSIONS

Both the Tecnis and FineVision IOLs provide a satisfactory range of vision, including a high level of uncorrected distance, intermediate, and near acuity and improved contrast sensitivity under photopic conditions.

Training of Resident Ophthalmologists in Cataract Surgery: A Comparative Study of Two Approaches

Purpose. To evaluate and compare the efficacy of two different training methods in resident-performed phacoemulsification surgery. Methods. 502 eyes of 467 patients who underwent resident-performed phacoemulsification were included in the study by reviewing their medical records. Residents were allocated into two groups according to the method applied during their training in cataract surgery; Group A included residents that were trained with the “step-by-step” method and Group B those trained with the “one-step” method. Primary outcome was the incidence of main complications, defined as posterior capsular ruptures and/or zonular dehiscence with vitreous loss. Results. Each resident performed a median of 63 phacoemulsification surgeries. A statistically significant difference (p = 0.0032) was noted in the main complications rate between the two groups, yielding a mean of 17.3% in Group A and 7.25% in Group B. Other intraoperative complications were not shown to differ statistically significantly between study groups (p > 0.05). Among the first 40 surgeries of each resident, main complications rate differed also statistically significantly (p = 0.0048) between Group A (21.67%) and Group B (8.5%), while a better surgical performance-yielding statistical significance in Group A (p = 0.017) was indicated in both groups between the 20th and the 30th procedure. Conclusions. Training in cataract surgery using the “one-step” method may lead to an improvement in surgical competency, when measured by complications rates and, therefore, to significantly better quality of training for resident ophthalmologists.

Protective role of C-phycocyanin against secondary changes during sodium selenite mediated cataractogenesis

Age related cataract is the leading cause of blindness associated with accumulation of oxidative stress in the eye lens. The present investigation reveals the rational of the beneficial effects of the natural compound C-phycocyanin (C-PC) is beneficial when administered to rat pups to protect against the secondary effects of sodium selenite induced cataractogenesis. A single subcutaneous dose of sodium selenite (19 μmol/kg body weight) on the 10th day of postpartum is adequate to induce cataract in rat pups. Serum biochemical parameters, such as the level of electrolytes, mean activities of anti-oxidant enzymes i.e. superoxide dismutase, catalase and reduced glutathione were observed to be significantly altered during selenite induced cataractogenic process. Histopathological examination revealed signs of degradation of normal cell architecture in the liver, kidney and eye lens. Interestingly, the deleterious effects of sodium selenite toxicity were restored with the simultaneous treatment with C-PC. The results suggest that an administration of 200 mg/kg body weight of C-PC has the ability to prevent/alter the secondary changes reflected in the serum biochemical and histological modifications in rats exposed to sodium selenite. These results complement the beneficial role of C-PC of cyanobacterial origin as a efficacious anti-cataractogenic agent against sodium selenite toxicity.