Biocompatibility of hydrophilic intraocular lenses

Characteristics and Risk Factors of Intraocular Lens Tilt and Decentration of Phacoemulsification After Pars Plana Vitrectomy

Purpose

The purpose of this study was to investigate the characteristics and risk factors of intraocular lens (IOL) tilt and decentration of phacoemulsification after pars plana vitrectomy (PPV) using swept-source optical coherence tomography (SS-OCT).

Methods

One hundred four eyes with prior PPV and 104 eyes without PPV undergoing uneventful cataract surgery were enrolled in this study. IOL tilt and decentration were measured by SS-OCT (CASIA2) 3 months postoperatively.

Results

The mean IOL tilt and decentration were greater in the PPV group (5.36 ± 2.50 degrees and 0.27 ± 0.17 mm, respectively) than in the non-PPV group (4.54 ± 1.46 degrees, P = 0.005; 0.19 ± 0.12 mm, P < 0.001, respectively). Multiple logistic regression showed that silicone oil (SO) tamponade (odds ratio [OR] = 5.659, P = 0.021) and hydrophilic IOL (OR = 5.309, P = 0.022) were associated with IOL tilt over 7 degrees, and diabetes mellitus (DM; OR = 5.544, P = 0.033) was associated with IOL decentration over 0.4 mm. Duration of SO tamponade was positively correlated with IOL tilt (P = 0.014) and decentration (P < 0.001). The internal total higher-order aberration, coma, trefoil, and secondary astigmatism in the PPV group were higher than in the non-PPV group, and positively correlated with IOL tilt (P < 0.05).

Conclusions

Patients with prior vitrectomy had greater IOL tilt and decentration than the non-PPV group. Longer duration of SO tamponade, hydrophilic IOL, as well as DM were the risk factors of greater IOL tilt and decentration in patients with prior PPV.

Translational Relevance

Optically sophisticated designed IOLs should be used cautiously in vitrectomized eyes.

Influence of super-hydrophobic silicone rubber substrate on the growth and differentiation of human lens epithelial cells

Materials with low cell adhesion are advantageous for production of replacement intraocular lens (IOL) to prevent posterior capsular opacification (PCO). We evaluated the feasibility of compression molding for manufacture of silicone rubber with super-hydrophobic surface and low cell infiltrative characteristics compared to ordinary hydrophobic silicone rubber. Silicone specimens with complex surface topology (super-hydrophobic) or smooth surfaces (hydrophobic) were manufactured by vacuum deforming and molding. Contact angle, microscopic surface structure, and transparency were evaluated. Super-hydrophobic and smooth samples were compared for effects on proliferation, adhesion, and morphology of human lens epithelial cells (hLECs). Epithelial-mesenchymal transition (EMT) was examined by immunofluorescence expression of fibronectin (Fn), Alpha-smooth muscle actin (α-SMA), and vimentin. The surface contact angle of super-hydrophobic silicone was greater than that of smooth silicone (153.8° vs. 116°). The super-hydrophobic surface exhibited a micron-scale palisade structure under scanning electron microscopy (unit length, width, and height of 80, 25, and 25 μm, respectively). However, cell number per 50 × microscopic field on super-hydrophobic surfaces was markedly reduced 24 and 72 h post-seeding compared to smooth surfaces (p < 0.01). Cells were cuboidal or spherical after 72h on super-hydrophobic surfaces, and exhibited numerous surface microvilli with fluff-base polarity, while cells on smooth surfaces exhibited morphological characteristics of EMT. Expression levels of the α-SMA and vimentin were reduced on super-hydrophobic surfaces compared to smooth surfaces. Super-hydrophobic silicon inhibits proliferation, adhesion, and EMT of hLECs, properties that may prevent fibrosis following cataract surgery.

RGD surface functionalization of the hydrophilic acrylic intraocular lens material to control posterior capsular opacification

Posterior Capsular Opacification (PCO) is the capsule fibrosis developed on implanted IntraOcular Lens (IOL) by the de-differentiation of Lens Epithelial Cells (LECs) undergoing Epithelial Mesenchymal Transition (EMT). Literature has shown that the incidence of PCO is multifactorial including the patient's age or disease, surgical technique, and IOL design and material. Reports comparing hydrophilic and hydrophobic acrylic IOLs have shown that the former has more severe PCO. On the other hand, we have previously demonstrated that the adhesion of LECs is favored on hydrophobic compared to hydrophilic materials. By combining these two facts and contemporary knowledge in PCO development via the EMT pathway, we propose a biomimetically inspired strategy to promote LEC adhesion without de-differentiation to reduce the risk of PCO development. By surface grafting of a cell adhesion molecule (RGD peptide) onto the conventional hydrophilic acrylic IOL material, the surface-functionalized IOL can be used to reconstitute a capsule-LEC-IOL sandwich structure, which has been considered to prevent PCO formation in literature. Our results show that the innovative biomaterial improves LEC adhesion, while also exhibiting similar optical (light transmittance, optical bench) and mechanical (haptic compression force, IOL injection force) properties compared to the starting material. In addition, compared to the hydrophobic IOL material, our bioactive biomaterial exhibits similar abilities in LEC adhesion, morphology maintenance, and EMT biomarker expression, which is the crucial pathway to induce PCO. The in vitro assays suggest that this biomaterial has the potential to reduce the risk factor of PCO development.

Determination of albumin sorption to intraocular lenses by radiolabeling and confocal laser scanning microscopy

PURPOSE

To determine albumin adsorption profiles and penetration depth of 3 intraocular lens (IOL) materials over time using confocal laser scanning microscopy (CLSM) and radiolabeling.

SETTING

Centre for Contact Lens Research, School of Optometry, and Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.

METHODS

Poly(methyl methacrylate) (PMMA), silicone, and foldable hydrophilic acrylic IOLs were incubated in 0.5 mg/mL bovine serum albumin (BSA) for 1, 7, and 14 days. The BSA was conjugated with lucifer yellow VS to allow identification of the protein location by fluorescent imaging with CLSM. Next, the protein uptake was quantified using 2% (125)I-labeled BSA.

RESULTS

Confocal laser scanning microscopy showed increasing BSA uptake for silicone and PMMA IOLs after 14 days of incubation (P<.05), with an apparent penetration depth of 8.7 microm +/- 1.9 (SD) and 9.2 +/- 1.4 microm, respectively. For hydrophilic acrylic IOLs, BSA was detected at a depth of 38 +/- 7.4 microm after 1 day, followed by an increase to 192.7 +/- 16.2 microm after 14 days. Despite the penetration depth into the hydrophilic acrylic IOLs, quantitative results confirmed that PMMA and hydrophilic acrylic deposited significantly less BSA (mean 278.3 +/- 41.7 ng and 296.5 +/- 33.1 ng, respectively) than silicone IOLs (mean 392.6 +/- 37.6 ng) (P<.05).

CONCLUSIONS

Silicone and PMMA IOL materials showed BSA sorption near the lens surface only, while BSA penetrated deep into the hydrophilic acrylic IOL matrix. Combining the qualitative CLSM method and quantitative radiolabeling technique provided detailed information on protein interactions with implantable biomaterials.

Longterm results of 1 CU® accommodative intraocular lens implantation: 2-year follow-up study

PURPOSE

To evaluate the longterm efficacy of 1 CU accommodative intraocular lenses (IOLs) to restore near visual performance.

METHODS

This prospective study comprised 14 eyes previously included in a 6-month, case-control clinical trial, undergoing phacoemulsification and implantation of a 1 CU accommodative IOL. The main outcome measures were subjective refraction, uncorrected distance visual acuity (UCDVA), best corrected distance VA (BCDVA), distance-corrected near VA (DCNVA), best corrected near VA (BCNVA), and subjective amplitude of accommodation (AA). In addition, anterior and posterior capsule opacification were assessed. Patients were examined over a 2-year follow-up period.

RESULTS

Distance and near visual performance worsened after 6 months. Uncorrected DVA and BCDVA were 0.8 +/- 2.1 and 1.0 +/- 0.8 at 6 months and 0.4 +/- 0.1 and 0.6 +/- 0.1 at 1 year, respectively (p = 0.001). Distance-corrected NVA and BCNVA were 3.7 +/- 2.1 Jaeger (J) and 1.0 +/- 0.7 J at 6 months and 8.1 +/- 0.7 J and 1.5 +/- 0.5 J at 1 year, respectively (p = 0.001). Anterior and posterior capsule opacification were present, respectively, in 28% and 21% of patients at 6 months and in 100% of patients at 1 and 2 years (p < 0.001). After Nd:YAG laser capsulotomy (performed in 100% of patients), UCDVA and BCDVA increased to 0.7 +/- 0.2 (p = 0.007) and 1.0 +/- 0.1 (p = 0.001), respectively, at 2 years. Distance-corrected NVA improved to 7.3 +/- 0.5 J (p = 0.006). Mean AA was 1.9 +/- 0.8 D at 6 months, 0.3 +/- 0.2 D (p = 0.004) at 1 year and 0.3 +/- 0.2 D at 2 years.

CONCLUSIONS

Patients implanted with 1 CU IOLs lost their accommodation capacities with time because of the high incidence and degree of anterior and posterior capsule opacification. The accommodative lens material and design may have played a role in capsule fibrosis.

Clinical effects of primary posterior continuous curvilinear capsulorhexis in eyes with single-piece hydrophilic acrylic intraocular lenses with and without haptic angulation

PURPOSE

To evaluate the clinical effects of a primary posterior continuous curvilinear capsulorhexis (PCCC) on the intraocular performance of hydrophilic acrylic single-piece intraocular lenses (IOLs) with and without haptic angulation.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

A prospective study comprised 52 patients with bilateral age-related cataract who had standard cataract surgery including a PCCC. One eye of each patient was randomized to receive a hydrophilic acrylic IOL with haptic angulation (ACR6D SE, Laboratoires Cornéal) and the contralateral eye, a hydrophilic acrylic IOL without haptic angulation (C-flex 570C, Rayner). The following parameters were assessed: regeneratory posterior opacification (RPO) in the central, intermediate, and peripheral areas (scale 0 to 10); anterior capsule opacification (ACO); best corrected visual acuity (BCVA); and contrast sensitivity (CSF).

RESULTS

Thirty-one patients completed the 1(1/2)-year follow-up. In both IOL groups, RPO within the PCCC was slight in the central area, with a mean score of 0.33 +/- 0.84 (SD) in the angulated IOL group and 0.16 +/- 0.57 in the nonangulated IOL group (P = .29). The mean RPO score in the peripheral area was 2.07 +/- 1.37 and 2.35 +/- 1.45, respectively (P = .12). The difference between the central and peripheral areas was 1.74 in the angulated IOL group (P<.00001) and 2.19 in the nonangulated IOL group (P<.00001). Haptic deformation occurred in 9 eyes (29%) with an angulated IOL and no eye with a nonangulated IOL. There was significantly more ACO in the nonangulated IOL group (P = .012). There were no significant differences in BCVA or CSF between the 2 groups.

CONCLUSIONS

Creating a PCCC led to significantly lower RPO intensity within the PCCC area than in the peripheral area in eyes with hydrophilic acrylic IOLs with and without haptic angulation. Haptic angulation had no apparent significant influence on the intensity of RPO or on BCVA and CSF. Haptic deformation may occur in hydrophilic IOLs with angulated haptics.

Effect of the hydrophilicity of acrylic intraocular lens material and haptic angulation on anterior capsule opacification

AIM

To evaluate the influence of hydrophilic and hydrophobic acrylic material and haptic angulation on anterior capsule opacification (ACO).

METHODS

Prospective study on 53 patients with bilateral age-related cataract. Patients underwent standard cataract surgery by the same surgeon and randomly received a hydrophilic acrylic intraocular lens (IOL) in one eye and a hydrophobic acrylic IOL in the other eye. Forty five of these patients completed the one-year follow-up. The following parameters were assessed: decentration, buttonholing, anterolenticular gap (ALG), ACO, outgrowth and refractive outcome.

RESULTS

At the one-year follow-up, ACO was seen in 80% of the hydrophilic and 100% of the hydrophobic IOLs. ACO was more intense in the hydrophobic IOLs (p<0.001). Outgrowth was seen in 42% of the hydrophilic and 2% of the hydrophobic IOLs (p = 0.0003). No case of persisting ALG was seen in the hydrophobic IOLs, but in 42% of the hydrophilic IOLs. The refractive outcome was -0.29 (SD 0.56) dioptres for the hydrophilic and 0.003 (SD 0.44) dioptres for the hydrophobic IOLs (p<0.001).

CONCLUSION

These results suggest that there is less ACO in hydrophilic acrylic than in hydrophobic acrylic IOLs. Although material properties might play a role, the angulated haptics of the hydrophilic IOLs exert an additional effect by the persisting ALG and a lack of contact between the IOL and the anterior capsule.

Modification of the surface properties of a lens material to influence posterior capsular opacification

PURPOSE

To study the effect of surface properties of materials on cellular behaviour and the formation of posterior capsular opacification (PCO).

METHODS

Polymethylmethacrylate, silicone and a hydrophobic acrylic were plasma treated and used in tissue culture. The changes in surface properties were quantified by dynamic contact angle measurements. Bovine lens epithelial cells (BLECs) were seeded onto these materials and cultured for 1 month. Serial photographs were taken. The cells were then fixed and stained to facilitate counting.

RESULTS

Plasma treatment significantly increased the hydrophilicity of surfaces. BLECs grew on all surfaces but significantly more cells adhered to the treated than the untreated surfaces. On the untreated surfaces the BLECs had a fibroblastic morphology whereas on the treated surfaces the cells maintained their epithelial morphology.

CONCLUSIONS

Posterior capsular opacification is a form of wound healing and the behaviour of lens epithelial cells is central to its progression. Emphasis has been on the elimination of residual lens epithelial cells to combat PCO. This study demonstrated that the phenotype of BLECs was influenced by the surface properties of the intraocular lens materials. Gas plasma treatment of the materials increased their hydrophilicity and allowed the adhered BLECs to maintain their normal epithelial morphology. We believe that controlled growth of lens epithelial cells may reduce the incidence of PCO.

Analysis of intraocular lens surface properties with atomic force microscopy

PURPOSE

To analyze the surface optics of 4 currently available intraocular lenses (IOLs) with atomic force microscopy.

SETTING

Licryl Laboratory, University of Calabria, Rende, Italy.

METHODS

The surface roughness and topography of poly(methyl methacrylate) (PMMA), silicone, hydrophobic, and hydrophilic acrylic IOLs were evaluated with atomic force microscopy in contact mode. The analysis was performed in a liquid environment using cantilevers with a 0.01 Newtonw/meter nominal elastic constant. Measurements were made over areas of 10 microm2 on different locations of the posterior optic surface of the IOL.

RESULTS

Atomic force microscopy permitted high-resolution imaging of IOL optic surface characteristics. Surface topography showed different features with respect to the lens biomaterial. The root-mean-square roughness of the IOL optic surface was significantly different between lenses of various materials (P < .001). The hydrophobic acrylic and silicone IOLs had the lowest mean surface roughness, 3.8 nm +/- 0.2 (SD) and 4.0 +/- 0.5 nm, respectively, and the 2 PMMA IOLs had the highest mean surface roughness, 6.6 +/- 0.3 nm and 7.0 +/- 0.6 nm.

CONCLUSIONS

Atomic force microscopy was effective and accurate in analyzing IOL optics. The surface topography of IOLs may vary with different manufacturing processes.

Chemoattraction of inflammatory cells by various intraocular lens materials

PURPOSE

To compare the chemotactic activity induced by polymethyl methacrylate (PMMA), acrylic, and silicone intraocular lens (IOL) materials, regardless of the surgical and host factors.

METHODS

The chemotactic effect of five different IOLs was studied using a modified multi-well Boyden chamber. Two different non-coated PMMA IOLs, a heparin-coated PMMA IOL, an acrylic IOL, and a silicone IOL were assessed. Each mean migration distance of the IOLs was compared with the others using Student's t test.

RESULTS

All IOLs induced some amount of leukocyte chemotaxis. There was no statistically significant difference between the chemotactic activity of PMMA IOLs. However, chemotactic activity was significantly higher in acrylic (p<0.05) and silicone (p<0.05) IOLs compared to one of the PMMA lenses.

CONCLUSIONS

This limited study has proven that chemotaxis assay is a useful tool to assess the biocompatibility of IOLs. The IOL material itself might attract inflammatory cells to its surface in the absence of surgical and host factors. As PMMA IOLs do not cause an increase in inflammatory reaction, they may be considered safe to use. Further improvement in chemical composition and surface characteristics of IOLs should reduce the inflammatory reaction and increase the biocompatibility and safety of IOLs.

Tissue reaction to hydrophilic intraocular lenses

The implant of intraocular lenses (IOLs) following cataract surgery induces a foreign body reaction to the IOL and a lens epithelial cell reaction. The host response to the IOL is mainly influenced by biomaterial properties. With the increasing use of phacoemulsification and small incision cataract surgery, there is growing interest in the use of foldable IOLs made of different materials. Hydrophilic acrylic IOLs include a wide group of foldable biomaterials different in terms of water content. These lenses have been reported to show a good biocompatibility after implantation. Nevertheless, tissue reaction to the implant of hydrophilic lenses is variable and not directly related to the hydrophilicity of their surface. A different adsorption of proteins on the IOL optic surface might be responsible for the different cellular reaction and lens epithelial cell response. Other properties besides hydrophilicity should be taken into account to classify IOL biomaterials.

Lens epithelial cell ongrowth: Comparison of 6 types of hydrophilic intraocular lens models

PURPOSE

To compare the ongrowth of lens epithelial cells (LECs) on the anterior surface of 6 different hydrophilic intraocular lenses (IOLs).

SETTING

Medical University of Vienna, Department of Ophthalmology and Optometry, Vienna, Austria.

METHODS

Six models of hydrophilic IOLs were compared in this prospective study: Visionflex A-100 (Distra Softcryl), Rayner Centerflex 570H (Rayner), Collamer CC4204BF-IOL (Staar), Injectacryl F 3000 (Distra), Hydroview H60M (Bausch & Lomb), and MemoryLens (ORC). Postoperative biomicroscopic examinations were performed 1, 3, 7, 30, 90, 180, and 365 days after surgery. Lens epithelial cells in each quadrant of the anterior capsule-free lens surface were graded. The product with the highest density and the number of quadrants with this density were used to measure LEC ongrowth.

RESULTS

The Hydroview and Visionflex IOLs showed significantly more LECs than the other IOLs starting on day 7 after surgery (P < .028). There was a statistically significant difference in LEC ongrowth on the Memory IOL compared with all other IOLs from day 30 onward (P < .001). The Rayner, Collamer and Injectacryl IOLs had the fewest LECs on the anterior surface compared with all other IOLs from day 7 until the final examination.

CONCLUSIONS

The findings show that LEC ongrowth on the IOL surface is material dependent. The findings suggest that the material of the recently developed hydrophilic IOLs induces less LEC ongrowth than older models.

Centripetal lens epithelial cell migration: a prospective study of the Alcon SA60AT intraocular lens

PURPOSE

To evaluate prospectively the incidence and severity of centripetal lens epithelial cell migration (CLECM) onto the anterior surface of the Alcon SA60AT intraocular lens (IOL).

METHODS

One hundred and four consecutive cases of SA60AT IOL implantations were prospectively evaluated. At the 1-month postoperative visit, best corrected visual acuity (BCVA) was obtained. Following maximal pupillary dilatation, the extent of CLECM was assessed using a simplified grading scale (0-4). The centrality of the lens within the capsular bag was recorded. Patients with the highest grade of CLECM were recalled for reassessment at a minimum of 3 months.

RESULTS

Centripetal lens epithelial cell migration data were obtained on 99 patients. Of these, 94% demonstrated CLECM of varying severity at 1 month postoperatively. The severity was low grade in 54% of patients (29% grade 1, 24% grade 2), and high grade in 40% of patients (16% grade 3, 24% grade 4). BCVA results were good (91.9% 6/6 or better) and did not correlate with CLECM grade. Operative capsulorhexis size did not correlate with the severity of CLECM. The lens was well-centred in 91 of 92 patients in whom lens position was assessed. Twenty-three patients with grade 4 CLECM at 1 month were brought back for reassessment (3.5-13 months postoperatively) and 18 of these demonstrated complete regression of CLECM (to grade 0).

CONCLUSIONS

There is a high incidence and severity of CLECM 1 month postoperatively using the Alcon SA60AT IOL. There was no significant correlation between CLECM grade and either BCVA at 1 month, capsulorhexis size or lens centration. CLECM appears to be a frequent, benign and transient event with this lens.

Free volume study on calcification process in an intraocular lens after cataract surgery

An opacified intraocular lens explanted from a patient in the postoperative period after phacoemulsification was investigated to find the cause of opacification. From the UV-visible and energy dispersive X-ray spectroscopy (EDS) measurements, the opacification in the present case seems to be due to calcification of the intraocular lens and not due to modification in the UV absorber material of the lens. The average free volume size of the intraocular lens both in unimplanted and explanted state were obtained from positron lifetime spectroscopy (PLS). Further, the combined FTIR and PLS results indicate that calcium gets into the free volume cavities of the intraocular lens matrix as a cationic moiety, may be in the form of Ca(++). The small decrease in glass transition temperature of the calcified lens seems to indicate the plasticizing action of calcium ions. The present results could be of some use in the design of the intraocular lens material in which calcification would be minimum.

Uveal and capsular biocompatibility of a single-piece, sharp-edged hydrophilic acrylic intraocular lens with collagen (Collamer): 1-year results

PURPOSE

To analyze uveal and capsular biocompatibility 1 year following implantation of a sharp-edged, hydrophilic, collagen-containing posterior chamber intraocular lens (IOL).

SETTING

Department of Ophthalmology, University of Vienna Medical School, Vienna, Austria.

METHOD

In a prospective study, a Collamer CC4204BF IOL was implanted in 30 eyes of patients with senile cataract. A standardized surgical technique and postoperative regimen were applied. To assess uveal biocompatibility, cellular inflammation on the anterior IOL surface was evaluated with a specular microscope. Capsular biocompatibility was registered semiquantitatively with a biomicroscope, based on an assessment of fibrosis on the anterior and posterior capsules. Tyndall values were measured with the Kowa FC-1000 laser flare-cell meter. Decentration of the lens was also registered.

RESULTS

One year after implantation, the values of flare and cell count in the anterior chamber were lower than preoperatively. Round and spindle-shaped, epithelioid, and foreign-body giant cells were not found on the anterior surface of the IOL. The capsulorhexis rim was moderately fibrosed in 56.6% of cases. Fibrosis of the capsule over the optic was also moderate in 36.6%. The central portion of the posterior capsule was devoid of fibrosis in 43.3% and mildly fibrosed in 50%. Three lenses revealed outgrowth of lens epithelial cells to the anterior surface of the IOL. A neodymium:YAG capsulotomy had to be performed in 1 case. All lenses were well centered in the capsular bag 1 year after implantation.

CONCLUSIONS

The absence of inflammatory cells on the anterior surface of the IOL indicates the high uveal biocompatibility of the lens. In terms of capsular biocompatibility, the results were satisfactory.

Posterior capsule opacification after implantation of a hydrogel intraocular lens

AIM

To compare the degree of posterior capsule opacification (PCO) in eyes with a hydrophilic hydrogel intraocular lens (IOL) with that in eyes with a hydrophobic acrylic IOL.

METHODS

Ninety five patients underwent a hydrogel IOL implantation in one eye and an acrylic IOL implantation in the opposite eye. The PCO value of these patients was measured using the Scheimpflug videophotography system at 1, 6, 12, 18, and 24 months postoperatively. The rate of neodymium:YAG (Nd:YAG) laser posterior capsulotomy and visual acuity were also evaluated.

RESULTS

The mean PCO value in the hydrogel group increased significantly (p<0.0001), while that in the acrylic group did not show significant change. The PCO value in the hydrogel group was significantly greater than that in the acrylic group throughout the follow up period. Kaplan-Meier survival analysis determined that the Nd:YAG capsulotomy rate in the hydrogel group was significantly higher than that in the acrylic group (p<0.0001). Mean visual acuity in the hydrogel group decreased significantly with time (p<0.0001), and became significantly worse than that in the acrylic group at 18 and 24 months postoperatively.

CONCLUSION

Posterior capsule opacification in eyes with a hydrophilic hydrogel IOL is significantly more extensive than that in eyes with a hydrophobic acrylic IOL, and results in a significant impairment of visual acuity.

Evidence of octacalcium phosphate and Type-B carbonated apatites deposited on the surface of explanted acrylic hydrogel intraocular lens

Fourier-transform infrared (FTIR) microspectroscopy combining with attenuated total reflection (ATR) microsampling technique and micro-Raman spectrophotometer were used to detect the deposited materials on the surface of acrylic hydrogel intraocular lens (IOL) with or without ocular implantation. Surface morphology and the interface of this IOL were further examined by a confocal laser scanning microscope. The brand-new IOL exhibited a very smooth, transparent and featureless surface, but the explanted IOL had an irregular cerebriform-like opaque appearance. Both FTIR/ATR and Raman microspectroscopic analyses showed the deposits on the surface of acrylic hydrogel IOL after ocular implantation to consist of octacalcium phosphate (OCP) and Type B carbonated apatites, leading to the opalescence of acrylic hydrogel IOL. Both vibrational microspectroscopic examinations also confirmed the mineralization still in progress on the surface of acrylic hydrogel IOL after ocular implantation for 2 years.

Clinical study of the 1CU accommodating intraocular lens

PURPOSE

To compare the near functional capacities of patients with an accommodating intraocular lens (IOL) with those of patients with a conventional monofocal IOL.

SETTING

Department of Ophthalmology, University of Chieti, Chieti, Italy.

METHODS

This prospective double-blind case-control study comprised 42 eyes that had phacoemulsification and implantation of 1 of 2 types of IOLs: HumanOptics accommodating 1CU(R) (study group) and Eurocrystal IFP 3G 6.00 (control group). The main outcome measures were subjective refraction, uncorrected distance acuity, best corrected distance acuity, distance corrected near acuity at 40 cm, best corrected near acuity at 40 cm, and subjective amplitude of accommodation. Patients were examined 7, 30, 90, and 180 days after surgery.

RESULTS

Postoperatively, both groups had excellent uncorrected distance acuity, best corrected distance acuity, and best corrected near acuity. In the study group, the mean distance corrected near acuity (Jaeger) was 5.43 +/- 0.98 (SD) (range 4 to 7) at 7 days, 2.33 +/- 0.48 (range 2 to 3) at 1 and 3 months, and 3.66 +/- 2.12 (range 2 to 7) at 6 months. In the control group, the mean distance corrected near acuity was 7.43 +/- 0.50 (range 7 to 8) during the entire follow-up. The differences between the groups was statistically significant (P<.001). The mean amplitude of accommodation was 0.00 diopter (D) in the control group and 1.14 +/- 0.44 D (range 0.75 to 2.00 D) in the study group at 7 days, 2.36 +/- 0.28 D (range 2.00 to 2.75 D) at 30 and 90 days, and 1.90 +/- 0.77 D (range 0.75 to 2.75 D) at 6 months.

CONCLUSIONS

The 1CU accommodating IOL provided better useful spectacle-free near visual acuity than the conventional monofocal IOL. However, the accommodating mechanism can play a role in capsule fibrosis.

Histology of anterior capsule opacification with a polyHEMA/HOHEXMA hydrophilic hydrogel intraocular lens compared to poly(methyl methacrylate), silicone, and acrylic lenses

To evaluate the biocompatibility of various materials including a poly(2-hydroxyethyl methacrylate [HEMA])/(6-hydroxyhexyl methacrylate [HOHEXMA]) hydrophilic hydrogel intraocular lens (IOL) (Hydroview, Bausch & Lomb). Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan. Ten opacified anterior capsules were extracted, including 3 specimens with the Hydroview IOL. They were processed for light and electron microscopy. Immunohistochemistry for alpha-smooth muscle actin (alpha SMA) and collagen types was also done to evaluate mesenchymal transition in lens epithelial cells (LECs). Anterior capsule opacification (ACO) in the 3 specimens with a polyHEMA/HOHEXMA hydrogel IOL contained more LECs and less extracellular matrix (ECM) than in the specimens with IOLs of other materials. Ultrastructural observation showed a well-organized collagenous ECM in tissues with an IOL of poly(methyl methacrylate), silicone, or soft acrylic material; an immature matrix was seen in specimens with a hydrogel IOL. The alpha SMA-positive LECs and collagen I and III, both types related to capsular wound healing, were detected in ACO.A polyHEMA/HOHEXMA hydrogel IOL facilitated the proliferation of LECs on the anterior capsule compared with other IOLs of other materials but did not completely suppress mesenchymal transition of LECs. Extracellular matrix accumulation appeared immature and less with a polyHEMA/HOHEXMA hydrogel IOL.