Anterior Surface Of Intraocular Lens Research Articles

Inhibition of anterior capsule opacification and contraction by the elevated anterior rim of the intraocular lens optic.

To verify the anterior capsule opacification (ACO) and contraction (ACC) of the ZCB00V intraocular lens (IOL), made of the same material as the AR40e with a high ACC rate. Retrospective cohort study. We evaluated 35 patients at 1 week, 1, 3 and 6 months post phacoemulsification with either a ZCB00V (n = 35) or FY-60AD (n = 34) IOL implantation. The ACC rate was calculated using retroillumination images of the anterior segment, and the ACO was measured using anterior segment photographs and image analysis software. The contact grade between the IOL and anterior capsule was estimated from the Pentacam® images. The postoperative ACC rates (mean ± standard deviation) at 3 months were 1.03%±2.54% for the ZCB00V and, and 7.12%±9.47% for the FY-60AD. The ZCB00V-implanted eyes showed a significantly lower postoperative ACC at 1 week, 3 months, and 6 months (P < 0.01). On the other hand, the FY-60AD-implanted eyes had more pronounced ACO, and a significantly larger area of opacification (62.24%±21.32% vs. 16.90%±8.34%; P = 0.0005). Pentacam® analysis revealed a space between the anterior capsule and IOL surface in the ZCB00V-implanted eyes, whereas the anterior capsule firmly adhered to the IOL surface in the FY-60AD-implanted eyes. The ACC and ACO were significantly lower in eyes with ZCB00V IOLs compared to those with the FY-60AD. The anterior segment image analysis revealed that the elevated anterior rim of the ZCB00V IOL prevented adhesion between the anterior capsule and IOL optic surface, suggesting an open capsule effect.

Determining specified intraocular lens powers when silicone oil is to be used in the vitreous chamber.

To apply a theoretical approach to determining how specified intraocular lens (IOL) powers should change when vitreous oil substitution is combined with IOL implantation. University laboratory, private Ophthalmological practice. Theoretical raytracing. Raytracing was done backwards from the retina with equi-convex 20 diopters (D) and 25 D IOLs, of refractive index 1.5332, to the object side of the anterior IOL surface. The 1.336 vitreous index was replaced with a high index 1.405 silicone oil. Raytracing was repeated with increase in specified power, that power as if 1.336 index was still surrounding the IOL, so that the object reduced vergence on the anterior side of the lens matched that of the original IOL power. This was done for a range of lens shapes from plano-convex (front surface flat), through equi-convex, to plano-convex (back surface flat), and for a range of axial lengths. The true power, the power with 1.336 index on the object side and silicone oil on the image side, was also determined. Replacing vitreous by silicone oil increases the necessary specified IOL power. This increase varies from approximately 14% for flat back surfaces, to 40% for equi-convex lenses, to 80% for flat front surface IOLs. True powers increase by about 15% across the range of IOL shapes. In terms of percentages, effects of changing the original IOL power and the axial length are small. When silicone oil is to remain in an eye after cataract surgery, biconvex IOLs require much higher specified powers than convex-plano IOLs.

Optical Quality Variation of Different Intraocular Lens Designs in a Model Eye: Lens Placed Correctly and in an Upside-Down Position

Introduction: Intraocular lenses (IOLs) may lose their optical quality if they are not correctly placed inside the capsular bag once implanted. One possible malpositioning of the IOL could be the implantation in an upside-down position. In this work, three aspheric IOLs with different spherical aberration (SA) have been designed and numerically tested to analyse the optical quality variation with the IOL flip, and misalignments, using a theoretical model eye. Methods: Using the commercial optical design software OSLO, the effect of decentration and tilt was evaluated by numerical ray tracing in two conditions: in their designed position and flipped with respect to the planned position (IOL is implanted upside down). The theoretical model eye used was the Atchison model eye. Seven IOL designs of +27.00 diopters were used: a lens with negative SA to correct the corneal SA, a lens to partially correct the corneal SA, and a lens to not add any SA to the cornea (aberration-free IOL). These lenses were designed with the aspherical surface located on the anterior and posterior IOL surface. A lens with no aspherical surfaces was also included. For the optical quality analysis, the modulation transfer function (MTF) was used, together with the Zernike wavefront aberration coefficients of defocus, astigmatism, and primary coma. Results: Off-centring and tilting the IOL reduced overall MTF values and increased wavefront aberration errors. With the IOL correctly positioned within the capsular bag, an aberration-free IOL is the best choice for maintaining optical quality. When the IOL is flipped inside the capsular bag, the optical quality changes, with the aberration-free IOL and the IOL without aspheric surfaces providing the worst results. With the lens in an upside-down position, an IOL design to partially correct corneal SA shows the best optical quality results in decentration and tilt, in terms of MTF and wavefront aberrations. Conclusion: The aberration-free IOL is the best choice when minimal postoperative errors of decentration or tilt are predicted. With IOL flip, the negative SA lens design is the best choice, regarding the root mean square wavefront aberrations. However, in a proper IOL implantation, the IOL designed to partially compensate the corneal SA including asphericity on its posterior surface is the better possible option, even in the presence of decentration or tilt.

A white daisy on intraocular lens

We report two patients with precipitation of Pseudo-exfoliative material (PXF) material on intraocular lens (IOL), a rare entity, years after uneventful cataract surgery. The PXF material was present on the anterior surface of the IOL optic in a characteristic radiating spoke-like manner, a pattern resembling shape of a white daisy flower. Emphasis is given on differentiating features between PXF deposition on natural lens and PXF deposition on IOL. Furthermore, how opacification of IOL is different from PXF on IOL is briefly explained. In the first case, PXF deposits were not found elsewhere except on anterior IOL surface and in the second patient, pupillary involvement was also noted along with settling on IOL optic. The fellow eyes in both the patients did not have PXF. PXF on IOL is a vital sign and should not be overlooked as it can be the only clue warranting thorough glaucoma evaluation.

Surface light scattering from 1-piece hydrophobic acrylic intraocular lenses with hydroxyethyl methacrylate: contralateral observation for 7 years.

To quantitatively and intraindividually compare surface light scattering for 7 years after implantation of Clareon and AcrySof intraocular lenses (IOLs). Miyata Eye Hospital, Miyazaki, Japan. Retrospective comparative case series. Clinical records of eyes that had contralateral implantation of SN60WF and SY60WF IOLs were reviewed. Light scattering on the anterior surface of IOLs, corrected distance visual acuity (CDVA), and mesopic and photopic contrast sensitivities were examined at 1 year, 3 years, and 7 years postoperatively, and they were intraindividually compared. 34, 19, and 16 patients visited at 1 year, 3 years, and 7 years postoperatively, respectively. Surface light scattering in eyes with SY60WF IOL was significantly reduced, and the rate of increase was 2.74 computer compatible tapes per year. Although there were prominent increases in eyes with SN60WF IOL, no statistically significant difference was found in their CDVA and contrast sensitivities. In eyes with Clareon IOLs, the development of surface light scattering was suppressed up to 7 years. The increase rate demonstrated that the visual acuity would be least deteriorated up to 12 years postoperatively, whereas the influence of straylight induced should be investigated.

Comparative effects of various types of toric intraocular lenses on astigmatism correction

BackgroundCurrently, various types of toric intraocular lenses (IOL) have been manufactured and can be divided into three types according to the location of correction component; front-toric IOL (correction on anterior IOL surface), back-toric IOL (correction on posterior IOL surface), and bi-toric IOL (correction on both anterior and posterior IOL surfaces). In this study, we aimed to investigate the effectiveness of reducing corneal astigmatism of either normal or post-penetrating keratoplasty (PKP) corneas according to the type of implanted toric IOLs.MethodsMedical records were retrospectively reviewed in 370 patients who had undergone phacoemulsification with posterior chamber toric IOL insertion (front-toric IOL, back-toric IOL or bi-toric IOL). Subjects were divided into 2 groups; subjects who had no history of corneal disease with corneal astigmatism more than 1.00 diopters (D) (G1) and subjects who received previous PKP with all corneal sutures removed and had corneal astigmatism more than 1.25 D (G2). Preoperatively intended target from SRK/T was evaluated. Refractive astigmatism and its vector analysis (J0, J45), mean numerical error (MNE) and mean absolute error (MAE) were assessed at least a month after cataract surgery.ResultsMean preoperative corneal astigmatisms were 2.2 D and 4.0 D in G1 and G2, respectively. There was significant reduction of mean postoperative refractive astigmatism to 0.89 D in G1 and to 2.33 D in G2. In G1, bi-toric IOL showed significantly more improved refractive astigmatism than back-toric IOL. In G2, no difference in refractive astigmatism according to toric IOL type was observed. While G2 showed no difference in MNE among toric IOLs, in G1, bi-toric IOL showed significant hyperopic shift compared to back-toric IOL. In both groups, there was no significant difference in MAE according to type of IOL. No postoperative complications were observed.ConclusionOur study suggests that all types of toric IOL are beneficial in correcting astigmatism of normal and post-PKP corneas. Noticeably, bi-toric IOL showed significantly better results in refractive astigmatism than back-toric IOL in normal cornea. However, bi-toric IOL showed a more hyperopic shift compared to back-toric IOL. Among post-PKP corneas, all types of toric IOL showed similar results.

Posterior capsule opacification and Nd:YAG laser rates with two hydrophobic acrylic single-piece IOLs.

To evaluate the development of posterior capsule opacification (PCO) and Nd:YAG capsulotomy rates following implantation of two hydrophobic acrylic IOLs. In a randomized, controlled trial, 80 patients with bilateral senile cataract were implanted with the hydrophobic acrylic single-piece intraocular Lenses (IOLs) EyeCee One in one eye and iMics1 in the other. Outcomes of 39 patients (78 eyes) were evaluated after 3 years. Automated Quantification of After-Cataract (AQUA; for PCO occurrence), visual acuity, anterior fibrosis, capsule-optic edge interaction and distance between anterior and posterior capsule IOL surface were analysed. After a mean follow-up of 38 ± 1.95 months, Nd:YAG capsulotomy occurred at a rate of 15.4% and 46.2% in the EyeCee One and iMics1 groups, respectively (p < 0.01). Respective mean PCO scores measured by AQUA were 1.57 ± 1.63 and 2.45 ± 1.44 (p = 0.019). A distinct gap between the anterior capsule and the IOL optic was present in 89% of eyes implanted with EyeCee One and 13% of iMics1 eyes. A gap between the posterior capsule and the posterior surface of the lens was observed in 76% of EyeCee One eyes and 35% of iMics1 eyes. Study findings suggest that PCO and Nd:YAG capsulotomy rates are significantly lower in eyes implanted with the EyeCee One IOL compared to the iMics1 IOL. Optic sharpness and lens material seem to be the decisive factors, while the stepped edge beneath the haptic junction appeared to be ineffective.

Optical imaging quality change of multifocal intraocular lens following Nd: YAG laser damage

Objective To study the optical imaging quality of multifocal intraocular lens (IOL) following Nd: YAG laser damage. Methods Three hydrophobic acrylate discs used to make multifocal IOL were placed in line, and the Nd: YAG laser was used to emit the posterior surface, mid-plane and anterior surface of the discs by gradually increasing the emitting energy to determine the damaged threshold energy of various planes.Eight multifocal IOLs were divided into 2 groups.IOL damage models were established by emitting 12 points along 12 clocks on circle of 3.0 mm in diameter in the group 1 (IOLs NO.1, 2, 3, 4) and 6 points with 1-clock interval on circle of 1.0 mm in diameter in the group 2 (IOLs NO.5, 6, 7, 8) with Nd: YAG laser.The modulation transfer function (MTF), line spread function (LSF) and United States air force (USAF) test target images of the IOLs were tested under the optical aperture at 2.0, 3.0 and 4.5 mm. Results The damage thresholds of laser power were not significantly different among three hydrophobic acrylate discs (Fgroup=1.100, P=0.337), and the thresholds were significantly different among different planes in the discs (Fposition=195.279, P=0.000), with the highest damage threshold in the anterior surface and the lowest damage threshold in the mid-plane of the discs(all at P<0.01). The shifts of far focus and near focus MTF curves, LSF curves and USAF target images of the IOLs under the 2.0, 3.0 and 4.5 mm optical aperture after laser damage were in coincidence with those before laser damage both in group 1 and group 2.The glare phenomenon of the USAF target image was observed at near focus under the 4.5 mm optical aperture both before and after laser damage. Conclusions Multifocal IOL is vulnerable to injury when the laser beam focuses on the mid-plane, and the anterior surface of IOL can tolerate certain degree of damage.In standard model eye, the MTF curves, LSF curves and USAF target images of multifocal IOL was not impacted by laser induced spots injuries under different pupil diameters. Key words: Nd: YAG laser; Intraocular lens; Imaging quality; Modulation transfer function; Line spread function; United States air force test target; Standard model eye

Steam-like clouding observed on anterior surface of intraocular lens developed soon after implantation

PurposeTo report our findings in three cases of a clouding of the anterior surface of an implanted intraocular lens that developed within 14 days after implantation. ObservationsThree eyes were implanted with the same model IOL and a steam-like clouding developed on the anterior surface of the IOL. The clouding occurred on days 4, 7, and 14 after the implantation in an area of the IOL that was in contact with the aqueous humor. The clouding was accompanied by a reduction of vision in all cases but without any other abnormalities such as inflammation. The clouding was resolved by irrigation and aspiration of the anterior chamber in 2 cases at 2 and 34 days after the onset, and a spontaneous disappearance in 1 case at 14 days after the onset of the clouding. After the disappearance of the clouding, the visual acuity improved, and there were no recurrences. The solution used to irrigate the anterior chamber was collected and examined to confirm the absence of cellular materials. Elemental analyses confirmed that sodium and chloride were the predominant ions. The IOL implanted was the XACT lens (Advanced Vision Science, USA) which is a hydrophobic acrylic IOL and is characterized by having higher water content compared to other IOLs. In addition, it is packaged in 0.9% saline to maintain the pre-hydrated condition. These aspects may be related to the cause of the clouding. This IOL was implanted in 3271 eyes in our clinic, and 3 of them (0.09%) developed this clouding. Conclusions and importanceWe report our findings in 3 eyes that developed a clouding on the anterior surface of the lens soon after implantation. The clouding was localized to the area in contact with the aqueous. The cause of the clouding was not determined.

Prediction of the true IOL position

PurposeTo develop algorithms for preoperative estimation of the true postoperative intraocular lens (IOL) position to be used for IOL power calculation.SettingMoorfields Eye Hospital NHS Foundation Trust, London, UK.MethodsFifty patients were...

Suppression of surface light scattering in intraocular lenses manufactured using an improved production process

To clinically examine the suppression of surface light scattering after implantation of an intraocular lens (IOL) manufactured using an improved production process. Miyata Eye Hospital, Miyazaki, Japan. Comparative case series. The prospective case series comprised eyes receiving hydrophobic acrylic Acrysof SN60WF IOLs that were manufactured before and after the improvement. Light scattering on the anterior IOL surface was examined up to 3years postoperatively using an EAS-1000 anterior segment analyzer. The changes during the postoperative period were evaluated and the 2 IOLs compared. The corrected distance visual acuity (CDVA) and contrast sensitivity under photopic and mesopic conditions were also examined 3years postoperatively. The case series comprised 24 eyes (received IOL before improvement) and 27 eyes (received IOL after improvement). After the improvement, the IOLs showed no increase in surface light scattering up to 2years, while there were increases after 2years in the other IOLs. The light scattering with the improved IOL was significantly reduced at all observations (P<.048, t test with Holm correction). No difference was found in the CDVA and contrast sensitivity. The improvement in the production process effectively decreased and slowed the development of surface light scattering. The slower increase in the improved IOL 3years postoperatively showed that the development of water aggregates would not be completely prevented. None of the authors has a financial or proprietary interest in any material or method mentioned.

Opacification of intraocular lens

SummarySoft hydrophobic acrylic intraocular lenses (IOLs) are increasingly being used because they can be implanted through small incisions, provide good postoperative vision. However, long‐term postoperative follow‐up has identified various problems, including calcification, glistening and whitening.Calcium deposit on surface of IOLs are sometimes reported about hydrophilic acrylic materials. Calcification reduces the transmission of light and renders the fundus virtually invisible and decrease visual function easily.Glistening has been attributed to water retention in voids of hydrophobic acrylic materials and nonuniformity of polymer network structures. Whitening refers to the clinical appearance from sub surface nano glistenings (SSNG) of reflected white light due to light scattering as light encounters nano sized fluid filled vacuoles that occur at the anterior and posterior IOL surface. With a hydrophobic IOL, the fundus remains visible despite opacification and less effect of visual function. As a result, removal and replacement of IOLs is indicated in only a few cases. However, sever glistening and whitening increased glare and decreased contrast sensitivity.

Anterior segment optical coherence tomography in black‐on‐clear polypseudophakia

Anterior segment optical coherence tomography in black‐on‐clear polypseudophakia

Effect on visual acuity of increased surface light scattering in intraocular lenses

To assess the long-term increase in surface light scattering of foldable hydrophobic acrylic intraocular lenses (IOLs) and to evaluate its effect on visual acuity. Miyata Eye Hospital, Miyazaki, Japan. Cross-sectional study. The clinical records of patients who received an Acrysof IOL (study group) or a Sensar AR40 or AR40e IOL (control group) were reviewed retrospectively. Surface light scattering of IOLs was measured 1 year postoperatively or later. The corrected distance visual acuity (CDVA) at the surface-light-scattering examination was compared with the CDVA 1 month after IOL implantation. The changes in CDVA over time were compared with the increase in surface light scattering. The study evaluated 466 eyes of 337 patients. Surface light scattering in the study group continued to increase up to 15 years postoperatively. The light scattering was higher on the anterior IOL surface after 4.5 years. Increased surface light scattering had no significant impact on CDVA; however, there were more cases with decreased CDVA when the surface light scattering exceeded 50 computer-compatible tape steps. Surface light scattering with the implanted foldable hydrophobic acrylic IOL continuously increased during the postoperative years and was a risk for decreased visual acuity.

Evaluation of Intraocular Lens Tilt With Anterior Segment Optical Coherence Tomography

To determine the ability of anterior segment optical coherence tomography (OCT) to detect intraocular lens (IOL) tilt evaluation in relation to the limbus. Observational case series. The IOL position of 123 eyes of 92 patients was examined with anterior segment OCT (Carl Zeiss Meditec, Dublin, California, USA). All eyes underwent uneventful phacoemulsification with the IOL in the bag. Images were obtained in 4 axes (180 to 0 degrees, 225 to 45 degrees, 315 to 135 degrees, and 270 to 90 degrees). Using MatLab software version 7.1 (Mathworks), the OCT images were analyzed. The distance between the iris margin and the anterior surface of IOL, the slope ratio between IOL and limbus, and the angle (θ; position of IOL with reference to the limbus) were determined and were correlated with the astigmatism and vision. The mean slope of the limbus and the IOL in all axes was 0.003 ± 0.09 and -0.002 ± 0.12, respectively. The average slope ratio was 1.1 ± 1 (range, -2.09 to 3.82) and the angle (θ) was 1.52 ± 0.9 degrees (range, 0.04 to 3.6 degrees). The mean ocular residual astigmatism was 0.2379 ± 0.469 diopters. There was no significant correlation of ocular residual astigmatism with slope ratio (r = -0.171; P = .060) and slope angle (r = -0.132; P = .147). There was significant correlation of ocular residual astigmatism with total astigmatism (r=0.602, p=0.000). The mean distances between the iris margin and the anterior surface of IOL at the pupillary plane were 0.80 ± 0.6 mm and 0.83 ± 0.57 mm, respectively. The normal in-the-bag IOL maintains an angle with reference to the limbus and a slope ratio without causing a significant tilt. Anterior segment OCT can be used as an alternative in IOL tilt evaluation by the analysis of its position in relation to the limbus.

Modification of hydrophobic acrylic intraocular lens with poly(ethylene glycol) by atmospheric pressure glow discharge: A facile approach

To improve the anterior surface biocompatibility of hydrophobic acrylic intraocular lens (IOL) in a convenient and continuous way, poly(ethylene glycol)s (PEGs) were immobilized by atmospheric pressure glow discharge (APGD) treatment using argon as the discharge gas. The hydrophilicity and chemical changes on the IOL surface were characterized by static water contact angle and X-ray photoelectron spectroscopy to confirm the covalent binding of PEG. The morphology of the IOL surface was observed under field emission scanning electron microscopy and atomic force microscopy. The surface biocompatibility was evaluated by adhesion experiments with platelets, macrophages, and lens epithelial cells (LECs) in vitro. The results revealed that the anterior surface of the PEG-grafted IOL displayed significantly and permanently improved hydrophilicity. Cell repellency was observed, especially in the PEG-modified IOL group, which resisted the attachment of platelets, macrophages and LECs. Moreover, the spread and growth of cells were suppressed, which may be attributed to the steric stabilization force and chain mobility effect of the modified PEG. All of these results indicated that hydrophobic acrylic IOLs can be hydrophilic modified by PEG through APGD treatment in a convenient and continuous manner which will provide advantages for further industrial applications.

Acrylic intraocular lens damage after folding using a forceps insertion technique

To analyze intraocular lens (IOL) surface abnormalities seen after folding using a forceps insertion technique. Mayo Clinic, Rochester, Minnesota, USA. Acrylic AcrySof MA60AC IOLs were examined using an Axio Imager microscope before and after they were folded using a forceps insertion technique. Differential interference contrast, brightfield reflected light, and darkfield reflected light imaging techniques were used as necessary. The effects of temperature, time, and ophthalmic viscosurgical device (OVD) on optic surface abnormalities after folding were studied. All 17 IOLs examined had smooth, defect-free optic surfaces before folding. After folding, anterior optic surface depressions were observed in all IOLs; the depressions corresponded to the contact area of the titanium insertion forceps. Surface depressions were present up to 72 hours after folding, were more pronounced when an insertion forceps with a high degree of wear was used, and were greater when the IOL was warmed to 98 degrees F before folding. Coating the IOL surface with OVD before grasping it with the insertion forceps prevented formation of depressions. The anterior optic surface of the acrylic IOL was vulnerable to forceps-induced surface depressions. Surface abnormalities were prevented by coating the anterior optic surface with OVD before grasping it with a metal insertion forceps.

Endophtalmie chronique après chirurgie de la cataracte

Delayed postoperative endophthalmitis following cataract surgery remains a rare complication. We report two cases of patients who presented with marked intraocular inflammation following uncomplicated cataract surgery. The patients did well for the first weeks after surgery (6 and 5 weeks). Both patients presented with visual impairment, inflammatory red eye, and a whitish plaque on the anterior surface of intraocular lenses. Posterior segment examination was normal in both cases. The two patients were treated with systemic antibiotic therapy as well as intravitreal and/or intracameral injections of antibiotics. The exact organism involved could not be identified in either patient. Each patient regained a final 20/25 visual acuity. Based on the clinical courses of these patients, the various possible therapeutic approaches for delayed postoperative endophthalmitis are discussed. This report underlines the problem of reaching the differential diagnosis between inflammation recurrence and delayed postoperative endophthalmitis as well as obtaining positive culture results if the latter diagnosis is suspected.

Uveal and capsular biocompatibility of an intraocular lens with a hydrophilic anterior surface and a hydrophobic posterior surface

To evaluate the uveal and capsular biocompatibility of intraocular lenses (IOLs) with a hydrophilic anterior surface and a hydrophobic posterior surface in a rabbit model. Eye Center, Affiliated Second Hospital, College of Medicine, Zhejiang University, Hangzhou, China. Modified silicone IOLs were produced by grafting 2-methacryloyloxyethyl phosphorylcholine (MPC) onto the anterior IOL surface using a plasma technique. A contact-angle test characterized the hydrophilicity of the IOL surface; physical and optical properties were determined by State Food and Drug Administration (SFDA) standards. Rabbits had phacomulsification and implantation a modified silicone IOL, a control silicone IOL, or a hydrogel IOL. Postoperative inflammation was assessed by aqueous flare measurement, and PCO was evaluated by software analysis. Three months after surgery, attached cells on extracted IOLs were evaluated by light microscopy; PCO was evaluated by Miyake-Apple technique. Histologic sections of globes were used to assess lens epithelial cells (LECs) and extracellular matrix in the capsular bag. Contact angle data showed the MPC-modified IOL had a hydrophilic anterior surface and hydrophobic posterior surface. The properties of the modified IOLs met SFDA standards. There was no statistical difference in aqueous flare between the IOL groups at any time. The modified and control IOLs had less PCO than the hydrogel IOLs (P<.05). There were fewer cells on modified IOLs than on silicone IOLs (P<.05). The LECs and cortical remnants on modified IOLs had a rapid, fibroblastic appearance at the optic periphery; the center was clear. Results suggest that the MPC-modified IOL has excellent uveal and capsule biocompatibility from hydrophilic anterior surface and hydrophobic posterior surface properties, respectively.

Phakic pattern of exfoliation material on a posterior chamber intraocular lens

Editor, Deposits of exfoliation material (XFM) on the anterior lens surface are the most consistent and important diagnostic feature of exfoliation syndrome (XFS). In phakic eyes, the characteristic pattern of XFM on the lens surface consists of three zones: (i) a central translucent disc; (ii) a clear intermediate zone; and (iii) a peripheral granular zone (Ritch & Schlötzer-Schrehardt 2001). The XFM is produced by several tissues of the anterior segment, including the iris pigment epithelium, non-pigmented ciliary epithelium and pre-equatorial lens epithelium. That the lens is unnecessary for the production of XFM is illustrated by its appearance years after cataract on intraocular lens (IOL) implants in pseudophakic eyes (Krause 1989; Ringvold & Bore 1990; Chen & Blumenthal 1992; Ritch 1994; Stewart & Jay 1995; FitzSimon & Johnson 1996). Most of these reports have portrayed scattered flecks of XFM on the surface of the IOL. Recently, two reports have been presented showing a pattern of mature deposition on the surfaces of IOLs years after implantation, suggestive of long-standing production, in patients who had no recorded findings of XFS prior to cataract surgery (Bahadur & Masket 2007; Park & Kee 2007). We would like to add another case of deposition of XFM on an IOL seen 10 years after lens implantation and in which the pattern of deposition reflected long-standing production of XFM with a granular appearance to the material extending over the surface of the IOL. An 82-year-old woman, with no history of glaucoma, presented with blurred vision in the left eye (OS) 10 years after extracapsular cataract extraction and implantation of a sulcus-fixated posterior chamber polymethylmethacrylate IOL. Her best-corrected visual acuity was 0.5 OS. Intraocular pressures were within normal limits. Slit-lamp biomicroscopy revealed XFM deposition on both the anterior and posterior surface of the IOL. The pattern of XFM accumulation on the anterior IOL surface showed a granular peripheral zone and radial striations in the intermediate zone without a clear central zone (Fig. 1A,B). The IOL was well centred and the pupil was round, reactive to light, and free of synechia and XFM deposits. Gonioscopy showed a hyperpigmented trabecular meshwork. The exfoliation material on the anterior surface of the intraocular lens has taken on a configuration similar to that of pregranular exfoliation syndrome, but is also deposited as densely as in phakic eyes with exfoliation syndrome. We feel that the appearance of the XFM on the lens surface in our case, and the others reported recently, can be explained by long-standing production in the absence of lens–pseudophakos friction. In the phakic eye, the central disc of XFM usually equals the pupillary diameter in size, and the intermediate clear zone is caused by friction of the iris on the lens anterior surface, rubbing the XFM off the mid-portion of the anterior lens surface and producing the classic three-ring appearance. When XFM is allowed to build up undisturbed in this region, it develops a granular appearance, similar to that found in the peripheral zone. However, in the presence of an IOL, space between the iris and the IOL prevents this rubbing, allowing the deposition of the material to progress undisturbed. Finally, one wonders why this phenomenon is rare, while XFS is extremely common, as is cataract extraction in these eyes. We conjecture that the distance from the posterior iris pigment epithelium, which produces the XFM, to the IOL is usually too large to allow deposition on the IOL surface and that any XFM secreted by these cells passes into the posterior chamber. Most of the eyes in the two other recent papers and our patient had IOL implantation in the sulcus, which would bring the IOL surface into closer contact with the iris. If the IOL is in the capsular bag but the zonules are loose, allowing the IOL and the bag to come forward, the same situation may apply.