Light transmittance of 1-piece hydrophobic acrylic intraocular lenses with surface light scattering removed from cadaver eyes.

PURPOSE: To assess the potential effect of surface light scattering on light transmittance of 1-piece hydrophobic acrylic intraocular lenses (IOLs) with or without a blue-light filter. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Intraocular lenses were obtained from human cadavers (49 IOLs total; 36 with blue-light filter) and from finished-goods inventory (controls). The IOLs were removed from cadaver eyes and the power and model matched to unused controls. After surface proteins were removed, the IOLs were hydrated for 24 hours at room temperature. Surface light scattering was measured with a Scheimpflug camera (EAS-1000 Anterior Segment Analysis System). Light transmittance was measured with a Lambda 35 UV/Vis spectrophotometer (single-beam configuration; RSA-PE-20 integrating sphere). RESULTS: Hydrated scatter values ranged from 4.8 to 202.5 computer-compatible tape (CCT) units for explanted IOLs with blue-light filter and 1.5 to 11.8 CCT units for controls; values ranged from 6.0 to 137.5 CCT units for explanted IOLs without a blue-light filter and 3.5 to 9.6 CCT units for controls. In both groups, there was a tendency toward increasing scatter values with increasing postoperative time. No differences in light transmittance were observed between explanted IOLs and controls in both groups (IOLs with blue-light filter: P=.407; IOL with no blue-light filter: P=.487; both paired t test). CONCLUSIONS: Although surface light scattering of explanted IOLs was significantly higher than that of controls and appeared to increase with time, no effect was observed on light transmittance of 1-piece hydrophobic acrylic IOLs with or without a blue-light filter.

Capsular bag opacification with a new accommodating intraocular lens.

PURPOSE: To evaluate the biocompatibility and capsular bag opacification of an accommodating intraocular lens (IOL) containing large haptic elements that separate the anterior and posterior capsules. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Bilateral phacoemulsification with IOL implantation was performed in 6 New Zealand rabbits. Each animal received a study (accommodating) IOL and a control (1-piece hydrophobic acrylic) IOL. Eyes were examined at the slitlamp from 1 day through 6 weeks postoperatively. The globes were then enucleated and evaluated grossly. Capsular bag opacification was scored from the posterior aspect (Miyake-Apple view). The eyes were then processed for complete histopathologic evaluation. RESULTS: At 6 weeks, the mean posterior capsule opacification (PCO) clinical score was 0.5 ± 0.3 (SD) in the study group and 3.0 ± 0.9 in the control group (P=.001, 2-tail paired t test). Anterior capsule opacification was practically absent in the study group and mild in the control group. Miyake-Apple posterior view showed a mean central PCO score of 0 ± 0 in the study group and 3.0 ± 1.1 in the control group (P=.001), peripheral PCO score of 0.7 ± 0.4 and 3.5 ± 0.8 (P=.0006), respectively, and Soemmerring ring score of 2.3 ± 0.8 and 7.0 ± 2.8 (P=.01), respectively. Histopathology showed no signs of toxicity in any eye. CONCLUSIONS: The study IOL maintained an expanded capsular bag secondary to the large size of the haptic elements, which appears to prevent capsular bag opacification.

Evaluation of a new single-piece 4% water content hydrophobic acrylic intraocular lens in the rabbit model.

PURPOSE: To evaluate uveal and capsular biocompatibility of a 1-piece intraocular lens (IOL) manufactured from a new hydrophobic acrylic material that incorporates a barrier step at the optic-haptic junctions. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: The study IOL (Eternity-Uni W-60) was implanted in the right eyes of 5 New Zealand rabbits and the control IOL (Acrysof SN60WF) in the left eyes. Slitlamp examination was performed 1 through 4 weeks postoperatively. After death, the globes were enucleated and fixed in formalin. Capsular bag opacification scoring (Miyake-Apple view) was then performed followed by complete histopathology. RESULTS: At the 4-week examination, the mean posterior capsule opacification (PCO) score was 1.5 ± 1.0 (SD) in the study group and 2.2 ± 1.09 in the control group (P=.02). Anterior capsule opacification (ACO) was not present in the study eyes and was mild in the control eyes. On gross examination, the mean central PCO score was 0.9 ± 0.65 in the study group and 1.7 ± 1.20 in the control group (P=.07); the mean peripheral PCO score was 1.3 ± 0.67 and 2.4 ± 1.14 (P=.01) and the mean Soemmerring ring score was 3.8 ± 0.44 and 4.2 ± 1.09, respectively (P=.47). Histopathology confirmed that both IOLs were equally tolerated by the rabbit eyes. CONCLUSIONS: In this rabbit study, the new hydrophobic acrylic material was biocompatible. The barrier step incorporated to the optic-haptic junctions has the potential to enhance PCO prevention.

Light scattering and light transmittance in intraocular lenses explanted because of optic opacification.

PURPOSE: To assess light scattering and light transmittance in intraocular lenses (IOLs) explanted because of optic opacification. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Poly(methyl methacrylate) (PMMA) IOLs with snowflake degeneration, hydrophilic acrylic IOLs with different calcification patterns, and 1 calcified silicone IOL explanted from an eye with asteroid hyalosis were studied with gross and light microscopy. Light scattering was measured with an EAS-1000 Scheimpflug camera. Light transmittance was measured with a Lambda 35 UV/Vis spectrophotometer (single-beam configuration with RSA-PE-20 integrating sphere). Analyses were performed at room temperature in the hydrated state and compared with controls. RESULTS: The study evaluated 8 PMMA IOLs, 22 hydrophilic acrylic IOLs, and 1 silicone IOL. Light scattering was as follows: 208 to 223 computer-compatible tapes (CCTs) for PMMA IOLs with snowflake degeneration (control = 9 CCTs); 90 to 227 CCTs for calcified hydrophilic acrylic IOLs (controls = 12 to 23 CCTs); 223 CCTs for the calcified silicone IOL (control = 5 CCTs). The mean light transmittance in the visible light spectrum was 81.08% to 97.10% for PMMA IOLs (control = 98.80%); 78.94% to 97.32% for hydrophilic acrylic IOLs (controls = 97.32% to 98.66%); 94.68% for the silicone IOL (control = 97.74%). CONCLUSION: Intraocular lens opacification led to very high levels of light scattering and a potential for decreased light transmittance, which play a role in the development of symptoms such as glare and halos, decreased contrast sensitivity, and eventually decreased visual acuity. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Prevention of capsular bag opacification with a modified hydrophilic acrylic disk-shaped intraocular lens.

PURPOSE: To evaluate the stability and capsular bag opacification with a modified disk-shaped 1-piece hydrophilic acrylic intraocular lens (IOL) suspended between 2 complete haptic rings connected by a pillar of the haptic material and with a commercially available 1-piece hydrophilic acrylic IOL. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Study and control IOLs were implanted into the left eyes and right eyes of 5 New Zealand rabbits. Eyes were examined at the slitlamp from 1 through 4 weeks. At 4 weeks, the globes were enucleated and evaluated under a very-high-frequency ultrasound. Photographs were taken and capsular bag opacification scored from the posterior aspect (Miyake-Apple view), and the eyes were processed for complete histopathology. RESULTS: At 4 weeks, the posterior capsule opacification score was 0.0 in the study group and 1.75 ± 0.5 (SD) in the control group (P=.005, paired t test). Ultrasound examination showed that 2 of the study IOLs had no contact between the posterior optic surface and the posterior capsule. Minimal proliferative cortical material was confined to the peripheral space between anterior and posterior rings of the study IOL haptics in localized areas at the equatorial region of the capsular bag. Anterior capsule opacification was absent in all eyes. CONCLUSIONS: The study IOL is a modification of a previous design, incorporating haptic perforations between the peripheral rings. By maintaining an open capsular bag and enhancing endocapsular inflow of aqueous, this modified design appears to prevent capsular bag opacification.

Anterior segment optical coherence tomography in the assessment of postoperative intraocular lens optic changes.

PURPOSE: To evaluate the use of anterior segment optical coherence tomography (AS-OCT) to assess postoperative intraocular lens (IOL) optic changes. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Intraocular lenses explanted because of various complications were used, including poly(methyl methacrylate) (PMMA) IOLs with snowflake degeneration, hydrophilic acrylic IOLs with calcification, a silicone IOL with calcification from an eye with asteroid hyalosis, and hydrophobic acrylic IOLs explanted because of decentration, subluxation, or uveitis-glaucoma-hyphema syndrome. After gross and light microscopy, the IOLs were examined in the dry and hydrated states using AS-OCT. Selected hydrophilic acrylic IOLs were stained for calcium. In-the-bag IOLs in pseudophakic cadaver eyes were also evaluated by AS-OCT before and after explantation to confirm correspondence with the clinical situation. RESULTS: Intraoptic changes, such as snowflake lesions in PMMA IOLs, calcification in hydrophilic acrylic IOLs, and glistenings in hydrophobic acrylic IOLs, could be imaged by AS-OCT. The method was also helpful in analyzing the location and density. However, in cases of more superficial changes, unless the lesions/deposits were present on the optic surface with an extension to the optic substance of at least 0.1 mm, they could not be clearly differentiated from the overall outline of the IOL surface. CONCLUSIONS: Anterior segment OCT may be helpful in assessing the presence, location, and density of intraoptic changes, avoiding a misdiagnosis of IOL opacification and the performance of unnecessary procedures, such as posterior capsulotomy or vitrectomy.

Long-term pathologic follow-up of obsolete design: Choyce Mark VIII anterior chamber intraocular lens.

We analyzed an enucleated eye that was blind and painful from a 66-year-old patient implanted with a Tennant modification of the Choyce Mark VIII anterior chamber intraocular lens (IOL) as a secondary procedure in 1978. The eye developed glaucoma, with implantation of an Ahmed valve in 2006. Gross and light microscopic analyses showed corneal decompensation and vascularization, peripheral anterior and posterior synechiae, iris thinning, significant changes in the iris pigmented layer, fibrous tissue on the anterior surface of the iris, and Soemmerring ring formation in the periphery of capsular bag remnants. In addition, there was severe attenuation of the nerve fiber layer and extensive cupping of the optic disc. The IOL surface was overall smooth and regular, without warping of the footplates, and was partially covered by clumps of various cell elements, including giant cells intermixed with pigment. This study represents the longest clinicopathologic correlation report on this IOL.

A prospective, contralateral comparison of photorefractive keratectomy (PRK) versus thin-flap LASIK: assessment of visual function.

PURPOSE: To compare differences in visual acuity, contrast sensitivity, complications, and higher-order ocular aberrations (HOAs) in eyes with stable myopia undergoing either photo-refractive keratectomy (PRK) or thin-flap laser in situ keratomileusis (LASIK) (intended flap thickness of 90 µm) using the VISX Star S4 CustomVue excimer laser and the IntraLase FS60 femtosecond laser at 1, 3, and 6 months postoperatively. METHODS: In this prospective, masked, and randomized pilot study, refractive surgery was performed contralaterally on 52 eyes: 26 with PRK and 26 with thin-flap LASIK. Primary outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), contrast sensitivity, and complications. RESULTS: At 6 months, mean values for UDVA (logMAR) were -0.043 ± 0.668 and -0.061 ± 0.099 in the PRK and thin-flap LASIK groups, respectively (n = 25, P = 0.466). UDVA of 20/20 or better was achieved in 96% of eyes undergoing PRK and 92% of eyes undergoing thin-flap LASIK, whereas 20/15 vision or better was achieved in 73% of eyes undergoing PRK and 72% of eyes undergoing thin-flap LASIK (P > 0.600). Significant differences were not found between treatment groups in contrast sensitivity (P ≥ 0.156) or CDVA (P = 0.800) at postoperative 6 months. Types of complications differed between groups, notably 35% of eyes in the thin-flap LASIK group experiencing complications, including microstriae and 2 flap tears. CONCLUSION: Under well-controlled surgical conditions, PRK and thin-flap LASIK refractive surgeries achieve similar results in visual acuity, contrast sensitivity, and induction of HOAs, with differences in experienced complications.