Glistenings in Modern IOL Materials - A Summary of the Peer-Reviewed Literature

 
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Glistenings in Modern IOL Materials - A Summary of the Peer-Reviewed Literature
Glistenings in
Modern IOL Materials
A Summary of the Peer-Reviewed Literature
Literature Review

Glistenings in IOL Materials
Abstract
Glistenings, or microvacuoles, have been observed with most modern IOL materials. Glistenings are tiny inclusions of
water present within the matrix of the IOL material that may be seen after implantation.
While glistenings can be identified by the eye care professional at the slit lamp, they are cosmetic in nature, and are
not generally observed by the patient.
A large body of peer-reviewed literature demonstrates that glistenings do not adversely affect visual function, as
measured using best-corrected visual acuity, contrast sensitivity, glare testing or wavefront measurements in human
eyes. Glistenings also appear to have no measurable effect on lens optics when measured in a laboratory setting.

Glistenings - Definition                                               observed with a thin slit beam at a 45° angle. They are
Glistenings, or microvacuoles, are reflections of light                usually more difficult to observe with retro illumination.
that occur from migrations of water within the matrix
of hydrated IOL material.1,2 Glistenings typically are 1               Formation of Glistenings
to 20 μm in size3,4,32,35 and present from 1 to 6 months               Microvacuoles result from water absorption and
postoperatively.3,5-7,9,32 Some studies suggest they are               subsequent condensation (phase separation) within the
stable over time,3,7,8,32 while others suggest they may be             matrix of the IOL material.1,2,32 Their formation appears to
progressive.5,9-11,32                                                  be influenced by temperature,1,3,4,29 inflammation21 and
                                                                       aqueous composition.30-32
Glistenings in Different Intraocular Lens Materials
Glistenings have been observed in most modern IOL                      Microvacuoles are not visible when an IOL is in a dry state.
materials including polymethylmethacrylate                             When an IOL is implanted, a certain amount of water is
(PMMA),12-14,32 silicone,9,13,15-17,32 hydrophilic acrylic9,18,19,32   absorbed. About 1 to 6 months postoperatively, phase
and hydrophobic acrylic.1-11,13,17,18,20-28,32                         separation may occur within the matrix of the IOL material,
                                                                       allowing minute water particles to condense and form
Glistenings are visible due to differences in refractive               microvacuoles.32
indices between the IOL material and water within the
IOL material. The larger the difference between these 2                All IOL materials have a limited uptake of water, thus,
refractive indices, the more apparent the microvacuoles.               the self-limiting factor in glistening formation is the
IOL material refractive indices are as follows:                        achievement of a state of equilibrium in water content
                                                                       within the IOL. For example, hydrophilic acrylic IOLs reach
    •   PMMA (1.49)                                                    a state of equilibrium at 18% to 33% water content, and
    •   silicone (1.43-1.46)                                           hydrophobic acrylic IOLs at 0.3% to 1.5%.32
    •   hydrophilic acrylic (1.47)
    •   hydrophobic acrylic (1.47 to 1.55)                             A change in temperature is the most commonly-used
                                                                       method of generating glistenings in vitro.4,9,29,33 The
Water has a lower refractive index [1.33] than any IOL                 glistenings formed in this manner are generally similar
material, which means that glistenings will be most                    to those that form in vivo; however, the density of in
apparent in those IOL materials with the highest                       vitro glistenings can sometimes exceed those that would
refractive index. If the index of refraction were equal,               be expected in a clinical setting.34 While not directly
for instance, glistenings would be unnoticeable, since                 comparable, glistenings created in vitro will have optical
the deviation of any light at the interface is a function of           properties and effects consistent with those in-vivo, when
the angle of incidence and the difference between the                  they are formed at clinically-relevant densities.
refractive indices of the materials on either side of the
interface.

The observance of microvacuoles changes as the angle
of the slit beam changes. Microvacuoles are usually best
Literature Review
Methodology                                                       settings“.34 They found “the optical quality of the acrylic
The US National Library of Medicine has an on-line medical        foldable intraocular lens is not significantly affected by the
publication search engine (pubmed.com) and database.              level of glistenings usually seen in the clinical setting“.34
This on-line database was searched using a wide range of          (See Figure 1) In a separate study, Miura et al created
terms designed to capture all potential articles related to       glistenings by immersing IOLs in in normal saline solution
glistenings.                                                      at 50°C for 2 hours and then at 35°C for 3 days. They
                                                                  examined possible polarization effects from glistenings
The search term below was used to identify all potential          and found no significant effect.35
articles:
(glistening* IOL) or (refractile IOL) or (vacuole* iol) or
(discolor* iol) or (deposit* IOL) or (glistening* intraocular
lens) or (refractile intraocular lens) or (vacuole* intraocular
lens) or (discolor* intraocular lens) or
(deposit* intraocular lens)

The intent was to ensure that miscategorized articles
(those that referenced internal deposits, for instance)
would not be missed. The expectation was that a high
number of unrelated articles would be returned, in order
to capture these few potentially miscategorized articles. A
total of 472 articles were identified.

Each abstract was reviewed and the article was classified
as related or unrelated to glistenings. Where there was any                                         Figure 1
                                                                      FROM OSHIKA et al. [Figure 1.] In-vitro glistenings and optical quality.
doubt, the article was classified as related to glistenings. A
more detailed review of the text of each article potentially
related to glistenings was then conducted, and the article        Impact on Vision
retained or discarded as the detailed review indicated. In        Seventeen studies, each with a minimum enrollment of 20
this manner 428 articles were eliminated and 44 articles          eyes, report on glistenings and their association with vision
were retained. Of the retained articles, one was an editorial     loss. A total of 1,843 eyes are included. .
with no new information, one described a general                  Three of the studies in question include patient evaluations
technique for measuring glistenings, one concerned                8 years or more after implantation, and account for 278
lens opacification but mentioned glistenings as a related         eyes (15% of the total).14,39,40 Monestam et al examined 103
phenomenon and one was a single case report in a French           eyes of 103 patients and graded the intensity of glistenings
journal and was not translated.The final 40 articles are          according to the photographic classification of Dhaliwal et
referenced in this paper.                                         al.26 They found that most patients had “severe glistenings“,
                                                                  but that “no detectable impact on BCVA, LCVA 10% and
Impact on Optical Quality, Measured In Vitro                      2.5% was found.“39 Hayashi et al studied 35 eyes more than
Of 18 in vitro studies of glistenings, the majority were          10 years after implantation, grading glistenings according
concerned with their formation and characteristics.               to the method of Miyata et al.3 They found “At more than
Only 2 studies measured optical quality as well.                  10 years postoperatively, visual function, including contrast
                                                                  sensitivity, and ocular HOAs were comparable among eyes
Oshika et al measured spectral transmittance, forward             that received acrylic, silicone, and PMMA IOLs. Glistenings
scatter, the modulation transfer function and resolving           with the acrylic IOLs were not significantly correlated
power at various contrasts with and without a glare               with visual function and optical aberrations.“40 The only
source. Several degrees of glistenings in the optic were          significant differences found between lenses were higher
experimentally created by immersing lenses in water at            light scatter and better corrected visual acuity in the
37°C for 48 hours and then at 25°C for 24 hours. Glistenings      acrylic group. Wilkins et. al. examined patients an average
were graded by inspection according to a visual scale             of 8 years postoperatively with a PMMA lens and found a
provided in the article, with Grade 1 being minimal               similar result; they saw significant glistenings but “did not
density. Grade 4+ glistening density was characterized            document any clinical impact.“14
as “extremely intense and… beyond the range of clinical
Literature Review
Table 1 shows a summary of the 17 studies in question                                           IN SUMMARY:
and the differences that were noted with regard to                                                • Glistenings are an observable phenomenon, using
glistenings and visual performance. The bulk of the                                             		 a slit lamp with an off-axis beam, in a wide array of
evidence points to the fact that glistenings, even when                                         		 intraocular lens materials, more evident in those
severe, have an insignificant impact on visual acuity                                           		 materials with a high index of refraction.
and other measures of visual function such as contrast                                            • Glistenings have been extensively investigated both in
sensitivity. In less frequent severe cases, glistenings did                                     		 vitro (artificially created) and in vivo.
not have a significant impact on high and low contrast                                            • In vitro testing has shown no effect of clinically-
visual acuity and other common measures of visual                                               		 relevant levels of glistenings on image quality or the
function such as contrast sensitivity.                                                          		 modulation transfer function of intraocular lenses.
                                                                                                  • In vivo clinical testing has included almost 2,000 eyes
In addition, three case studies suggested an effect on                                          		 (some control eyes) reported in 17 different clinical
visual function. In one case where glistenings were                                             		studies.
suspected as the cause of reduced visual acuity, a repeat                                       			 - Long term studies, which included a significant
YAG capsulotomy was performed that restored visual                                              				 percentage of eyes with severe glistenings, have
acuity.36 In the second case, the effects from glistenings                                      				 shown no effect on best corrected visual acuity,
could not be separated from the lens tilt and the                                               				 low contrast visual acuity or higher order
progressive hyperopia that the patient experienced after                                        				 aberrations of the eye.
undergoing a YAG capsulotomy.37 In the third case, the                                          			 - There has been no reported effect of glistenings
retina was compromised, so the visual impact of the                                             				on contrast sensitivity.
glistenings could not be measured: the presentation of                                          			 - 16 of 17 studies representing 99.9% of all eyes
glistening formation in this case was also atypical.38                                          				 studied show no significant difference in best
                                                                                                				corrected visual acuity.
Table 1 - Brief Summary of Peer Reviewed Studies
                                                                                                                           Difference reported due to glistenings in:
                                                                                                                       Contrast      Low Contrast    Brightness    Scotopic
 Ref                                                 Title                                               n    BCVA    Sensitivity       Acuity       Acuity Test    Vision    HOAs
   9    Glistenings in foldable intraocular lenses                                                      273   No
   7    Glistenings in a large series of hydrophobic acrylic intraocular lenses                         260   No
  18    Image analysis of implanted rigid and foldable intraocular lenses in human                      190   No                                         No             No
        eyes using Scheimpflug photography
  21    Clinical factors related to the frequency and intensity of glistenings in                       129   No
        AcrySof® intraocular lenses
  10    Long-term results of wagon wheel packed acrylic intra-ocular lenses (AcrySof®)                  115   No
  20    Incidence of glistenings with the latest generation of yellow-tinted                            111   No
        hydrophobic acrylic intraocular lenses
  39    Impact on visual function from light scattering and glistenings in intraocular                  103   No                          No
        lenses, a long-term study
  40    Long-term effect of surface light scattering and glistenings of intraocular                     102   No                      No (with                                No
        lenses on visual function                                                                                                    or without
                                                                                                                                        glare)
   8    Glistenings on intraocular lenses in healthy eyes: effects and associations                      97   No          No
  27    Effects on visual function of glistenings and folding marks in                                   91   No                         Yes*
        AcrySof® intraocular lenses
  14    Glistenings with long-term follow-up of the Surgidev**** B20/20                                  73   No
        polymethylmethacrylate intraocular lens
  5     Clinical evaluation of the transparency of hydrophobic acrylic intraocular                       65   No
        lens optics
  30    Surfactant induced glistenings: surface active ingredients in ophthalmic                         63   No
        solutions may enhance water entry into the voids of implanted acrylic
        intraocular lenses
  26    Visual significance of glistenings seen in the AcrySof® intraocular lens                         56  No                         Yes**            No
  11    Glistenings in the single-piece, hydrophobic, acrylic intraocular lenses                         53  No           No
  24    Glistenings in the AcrySof® intraocular lens: pilot study                                        42 Yes***    No, with or                        No
                                                                                                                     without glare
  16    Glistenings in the Artiflex**** phakic intraocular lens                                          20   No

* non-standard contrast acuity test, different only at highest spatial frequency
** eye with partial iridotomy in AcrySof® IOL group
*** Snellen acuities averaged (yields incorrect results, equivalent logMAR shows no significant difference)
**** Trademarks are property of their respective owners
References
1. Miyata A, Yaguchi S. Equilibrium water content and              7. Colin J, Orignac I, Touboul D. Glistenings in a large series of
   glistenings in acrylic intraocular lenses. J Cataract Refract       hydrophobic acrylic intraocular lenses. J Cataract Refract
   Surg. 2004 Aug;30(8):1768-72. PubMed PMID: 15313305                 Surg. 2009 Dec;35(12):2121-6 PubMed PMID: 19969218
   CONCLUSION: The change in the equilibrium water content             CONCLUSION: The results suggest a potential association
   caused by temperature changes between 30 degrees C                  between the incidence of glistenings and IOL power and
   and 40 degrees C is an important factor in glistening               glaucoma, but not between glistenings and age, sex,
   formation, and thus an IOL featuring less temperature-              IOL model, length of follow-up, CDVA, SE, or most ocular
   dependent water absorption is less likely to form                   and systemic diseases and medications.
   glistenings.                                                    8. Colin J, Orignac I. Glistenings on intraocular lenses in
2. Kato K, Nishida M, Yamane H, Nakamae K, Tagami Y,                   healthy eyes: effects and associations. J Refract Surg. 2011
   Tetsumoto K. Glistening formation in an AcrySof lens                Dec;27(12):869-75. doi: 10.3928/1081597X-20110725-01.
   initiated by spinodal decomposition of the polymer                  Epub 2011 Jul 29. PubMed PMID: 21800784
   network by temperature change. J Cataract Refract Surg.             CONCLUSION: In healthy eyes, glistening grade was not
   2001 Sep;27(9):1493-8 PubMed PMID: 11566536                         associated with contrast sensitivity, CDVA, intraocular light
   CONCLUSION: Glistenings formed in the bulk of an AcrySof®           scatter, or any lens or demographic characteristics that were
   IOL as the medium temperature decreased. The mechanism              investigated.
   may involve spinodal decomposition of the swollen               9. Tognetto D, Toto L, Sanguinetti G, Ravalico G. Glistenings
   polymer network, which initiates the formation of                   in foldable intraocular lenses. J Cataract Refract Surg. 2002
   microvacuoles consisting of water and loosely packed                Jul;28(7):1211-6. PubMed PMID: 12106730
   network chains.                                                     CONCLUSION: Glistening formation was observed in
3. Miyata A, Uchida N, Nakajima K, Yaguchi S. Clinical and             7 different foldable IOLs. The AcrySof® group had a higher
   Experimental Observation of Glistening in Acrylic                   percentage and a greater density of glistenings.
   Intraocular Lenses. Jpn J Ophthalmol. 2000 Nov 1;44(6):693.     10. Peetermans E, Hennekes R. Long-term results of wagon
   PubMed PMID: 11094201                                               wheel packed acrylic intra-ocular lenses (AcrySof). Bull Soc
   CONCLUSION: The glistening in acrylic intraocular lenses            Belge Ophtalmol. 1999;271:45-8. PubMed PMID: 10355159
   seemed to become stable a few months after appearance.              CONCLUSION: Vacuoles, as described with the AcryPak®
   Thus our experimental method is useful, because it gives us         system, were also detectable in our Wagon Wheel packed
   glistening similar to clinical cases in a short time.               lenses. They increased significantly in incidence and
4. Gregori NZ, Spencer TS, Mamalis N, Olson RJ. In vitro               number with time.
   comparison of glistening formation among hydrophobic            11. Waite A, Faulkner N, Olson RJ. Glistenings in the single-
   acrylic intraocular lenses(1). J Cataract Refract Surg. 2002        piece, hydrophobic, acrylic intraocular lenses. Am J
   Jul;28(7):1262-8. PubMed PMID: 12106738                             Ophthalmol. 2007 Jul;144(1):143-4. PubMed PMID:
   CONCLUSION: Glistening quantity varied among                        17601442
   hydrophobic acrylic IOLs and was temperature dependent.             CONCLUSION: All IOLs studied had glistenings. High spatial
   Sensar* IOLs were more stable than the 2 other IOL types.           resolution contrast sensitivity impact and severity
   The glistening phenomenon must be studied further to                progression over time deserve further study.
   eliminate the problem.                                          12. Ballin N. Glistenings in injection-molded lens. J Am Intraocul
   * Trademarks are property of their respective owners.               Implant Soc 1984 Fall;10(4):473. PubMed PMID: 6501064
5. Nagata M, Matsushima H, Mukai K, Terauchi W, Senoo T,               CONCLUSION: None, a letter to the editor first identifying
   Wada H, Yoshida S. Clinical evaluation of the transparency          glistenings in IOLs.
   of hydrophobic acrylic intraocular lens optics. J Cataract      13. Rønbeck M, Behndig A, Taube M, Koivula A, Kugelberg M.
   Refract Surg. 2010 Dec;36(12):2056-60. PubMed PMID:                 Comparison of glistenings in intraocular lenses with
   21111307                                                            three different materials: 12-year follow-up.
   CONCLUSION: Our results suggest that AcrySof® SA60AT                Acta Ophthalmol. 2011 Oct 28. doi: 10.1111/j.1755-
   and AF-1 VA-60BB IOLs are likely to develop glistenings over        3768.2011.02277.x [Epub ahead of print] PubMed PMID:
   time and that the former may develop whitening.                     22035345
6. Davison JA. Clinical performance of Alcon SA30AL and                CONCLUSION: In this long-term follow-up study, the
   SA60AT single-piece acrylic intraocular lenses. J Cataract          hydrophobic acrylic IOL had a significantly higher degree
 Refract Surg. 2002 Jul;28(7):1112-23 PubMed PMID: 12106718           of lens glistenings compared to the silicone and PMMA
   CONCLUSION: The single-piece acrylic lenses performed               IOLs. The PMMA IOL had almost no lens glistenings. The IOL
   well in all regards. Although not as intense as observed            dioptric power was not significantly correlated with the
   with the earlier 3-piece designs, pseudophakic                      degree of lens glistenings associated with the hydrophobic
   dysphotopsia occurred in a few patients with the single-            acrylic IOL.
   piece acrylic lens. Intraocular lens exchanges with single-     14. Wilkins E, Olson RJ. Glistenings with long-term follow-up
   piece IOLs may be accomplished with less difficulty early           of the Surgidev B20/20 polymethylmethacrylate intraocular
   rather than late.                                                   lens. Am J Ophthalmol. 2001 Nov;132(5):783-5. PubMed
References
      PMID: 11704044                                                          hydrophobic acrylic intraocular lenses. J Cataract Refract
      CONCLUSION: Glistenings may occur in                                    Surg. 2012 Jul;38(7):1140-6. PubMed PMID: 22727284
      polymethylmethacrylate intraocular lenses with long-term                CONCLUSION: Glistenings were common in eyes with the
      follow-up, and they are progressive.                                    blue light-filtering hydrophobic acrylic IOL and increased
15.   Miyata A, Uchida N, Nakajima K, Yaguchi S. [Experimental                over time.
      study of glistening in silicone intraocular lenses]. Nihon        21.   Moreno-Montañés J, Alvarez A, Rodríguez-Conde R,
      Ganka Gakkai Zasshi. 2002 Feb;106(2):112-4. Japanese.                   Fernández-Hortelano A. Clinical factors related to the
      PubMed PMID: 11915372                                                   frequency and intensity of glistenings in AcrySof®
      CONCLUSION: The presence of numerous microvacuoles                      intraocular lenses. J Cataract Refract Surg. 2003
      in the SI40NB means there may be GP. The light clouding                 Oct;29(10):1980-4. PubMed PMID: 14604721
      in the AQ110NV that was resolved with drying is thought to              CONCLUSION: The frequency and intensity of glistenings in
      be due to particles in the material which cause                         AcrySof® IOLs increased with time after surgery
      discoloration.                                                          and were higher when postoperative inflammation
16.   Cisneros-Lanuza A, Hurtado-Sarrió M, Duch-Samper                        was present. Glistenings developed more frequently
      A, Gallego-Pinazo R, Menezo-Rozalén JL. Glistenings in the              in cases of phacotrabeculectomy but not after combined
      Artiflex phakic intraocular lens. J Cataract Refract Surg. 2007         phacoemulsification and deep sclerectomy. Glistenings did
      Aug;33(8):1405-8. PubMed PMID: 17662432                                 not result in decreased Snellen BCVA.
      CONCLUSION: Glistenings appeared some Artiflex* pIOLs             22.   Mamalis N. Intraocular lens glistenings. J Cataract Refract
      to varying degrees, although they were not visually                     Surg. 2012 Jul;38(7):1119-20. PubMed PMID: 22727278
      significant in any case. A larger study of this IOL is needed           CONCLUSION (EDITORIAL COMMENT): Even significant
      to determine whether severe cases of glistenings affect                 glistenings and high-level light scattering from the IOLs
      visual function and assess their cause and evolution over               have not been shown to have a detectable impact on CDVA
      time.* Trademarks are property of their respective owners.              or low contrast visual acuity.
17.   Schauersberger J, Amon M, Kruger A, Abela C, Schild               23.   Chehade M, Elder MJ. Intraocular lens materials and styles: a
      G, Kolodjaschna J. Comparison of the biocompatibility of                review. Aust N Z J Ophthalmol. 1997 Nov;25(4):255-63.
      2 foldable intraocular lenses with sharp optic edges. J                 Review. PubMed PMID: 9395827
      Cataract Refract Surg. 2001 Oct;27(10):1579-85. PubMed                  CONCLUSION: Soft acrylic IOL unfold slowly, resulting in
      PMID: 11687355                                                          controlled insertion, but it is possible to crack the lens and
      CONCLUSION: The findings show that a sharp-edged optic                  some lenses develop glistenings due to water
      design is, to date, the most effective method of reducing               accumulation. There are significant socioeconomic
      the rate of PCO. Despite a subclinical foreign-body reaction            implications to the large differences in posterior capsule
      in the AcrySof® group, both lenses had a high degree of                 opacification rates between the various biomaterials and
      capsular and uveal biocompatibility.                                    the lens styles.
18.   Klos KM, Richter R, Schnaudigel O, Ohrloff C. Image               24.   Christiansen G, Durcan FJ, Olson RJ, Christiansen K.
      analysis of implanted rigid and foldable intraocular lenses in          Glistenings in the AcrySof® intraocular lens: pilot study. J
      human eyes using Scheimpflug photography. Ophthalmic                    Cataract Refract Surg. 2001 May;27(5):728-33. PubMed
      Res. 1999;31(2):130-3. PubMed PMID: 9933775                             PMID: 11377904
      CONCLUSION: Thus, we found in foldable IOLs 'glistenings',              CONCLUSION: Glistenings occurred frequently in AcrySof®
      which did not have any influence on functional results                  IOLs, with most cases mild. A larger study of this lens is
      and we could distinguish them from lens damage.                         needed to determine whether severe presentations affect
      We propose to use Scheimpflug tests regularly for the                   visual function and to understand how glistenings change
      examination of implanted new types of IOLs.                             over time.
19.   Fujita S, Tanaka T, Miyata A, Hirose M, Usui M. Cell adhesion     25.   Prosdocimo G, Tassinari G, Sala M, Di Biase A, Toschi PG,
      and glistening formation in hybrid copolymer intraocular                Gismondi M, Corbanese U. Posterior capsule opacification
      lenses. Ophthalmic Res 2012;48(2):102-8. Epub 2012 Apr 18.              after phacoemulsification: silicone CeeOn* Edge versus
      PubMed PMID: 22517197                                                   acrylate AcrySof® intraocular lens. J Cataract Refract Surg
      CONCLUSION: The MA IOLs exhibited a low level of                        2003 Aug;29(8):1551-5. PubMed PMID: 12954304
      adhering cells but a high level of glistening formation,                CONCLUSION: Both the CeeOn* Edge and AcrySof® groups
      the HEMA IOL exhibited the reverse tendency, and the MA/                had a low incidence of PCO after an 18-month follow-
      HEMA IOL exhibited a low level of both, thus indicating that            up. The CeeOn* Edge group had significantly less PCO than
      hybrid MA/HEMA IOLs are less susceptible than HEMA IOLs                 the AcrySof® IOL group. These results confirm that IOLs with
      to cell adhesion and less susceptible than MA IOLs to                   square truncated edges create a barrier effect at the optic
      glistening formation.                                                   edge, reducing the overall incidence of PCO.
20.   Colin J, Praud D, Touboul D, Schweitzer C. Incidence                    * Trademarks are property of their respective owners.
      of glistenings with the latest generation of yellow-tinted
References
26. Dhaliwal DK, Mamalis N, Olson RJ, Crandall AS,                         Res. 2001 Mar-Apr;33(2):61-7. PubMed PMID: 11244349
    Zimmerman P, Alldredge OC, Durcan FJ, Omar O. Visual                   CONCLUSION: The number of vacuoles increases with
    significance of glistenings seen in the AcrySof intraocular            incubation time in aqueous humor containing serum.
    lens. J Cataract Refract Surg. 1996 May;22(4):452-7. PubMed            The addition of serum increased the proportion of
    PMID: 8733849                                                          lipids and proteins in the solution, which also occurs with
    CONCLUSION: Patients who received AcrySof® IOLs that                   a breakdown in the blood-aqueous barrier. The results of
    came in the AcryPak® had some degree of glistenings.                   the present study point to a physiological factor that may
    There was also a significant decrease in contrast sensitivity          lead to vacuole formation in IOLs and may aid clinicians in
    compared with that of fellow eyes with silicone IOLs. The              identifying risk factors involved in the formation of
    glistenings are likely caused by water vacuoles that form              vacuoles.
    within the lens after hydration within the eyes. Further         32.   Werner L. Glistenings and surface light scattering in
    studies are necessary to assess the exact cause of these               intraocular lenses. J Cataract Refract Surg. 2010
    glistenings.                                                           Aug;36(8):1398-420. Review. PubMed PMID: 20656166
27. Gunenc U, Oner FH, Tongal S, Ferliel M. Effects on visual              CONCLUSION: Although the impact of glistenings on
    function of glistenings and folding marks in AcrySof®                  postoperative visual function and the evolution
    intraocular lenses. J Cataract Refract Surg. 2001                      of glistenings in the late postoperative period remain
    Oct;27(10):1611-4. PubMed PMID: 11687360                               controversial, IOL explantation has rarely been reported.
    CONCLUSION: Although glistenings and folding marks were          33.   Shiba T, Mitooka K, Tsuneoka H. In vitro analysis of AcrySof
    observed after the implantation of AcrySof®IOLs, they did              intraocular lens glistening. Eur J Ophthalmol. 2003 Nov-
    not significantly affect visual function.                              Dec;13(9-10):759-63. PubMed PMID: 14700095
28. Allers A, Baumeister M, Steinkamp GW, Ohrloff C,                       CONCLUSION: AcrySof® lenses soaked in warm water for
    Kohnen T. [Intra-individual comparison of intraocular                  a short time may change characteristics, and therefore,
    lenses of highly refractive silicone (Allergan SI40NB) and             close monitoring of the temperature and time of soaking is
    hydrophobic acrylate (Alcon Acrysof MA60BM). 1-year                    necessary to prevent glistening formation.
    follow-up] Ophthalmologe. 2000 Oct;97(10):669-75.                34.   Oshika T, Shiokawa Y, Amano S, Mitomo K. Influence of
    German. PubMed PMID: 11105542                                          glistenings on the optical quality of acrylic foldable
    CONCLUSION: One year after implantation of foldable,                   intraocular lens. Br J Ophthalmol. 2001 Sep;85(9):1034-7.
    highly refractive silicone and hydrophobic acrylic IOLs                PubMed PMID: 11520749; PubMed Central PMCID:
    using a self-sealing tunnel incision and phacoemulsification,          PMC1724105
    no significant functional or morphological differences                 CONCLUSION: The optical quality of the acrylic foldable
    between the two IOL types were observed.                               intraocular lens is not significantly affected by the level of
29. Omar O, Pirayesh A, Mamalis N, Olson RJ. In vitro analysis             glistenings usually seen in the clinical setting.
    of AcrySof® intraocular lens glistenings in AcryPak®             35.   Miura M, Osako M, Elsner AE, Kajizuka H, Yamada K, Usui M.
    and Wagon Wheel packaging. J Cataract Refract Surg. 1998               Birefringence of intraocular lenses. J Cataract Refract Surg.
    Jan;24(1):107-13. PubMed PMID: 9494907                                 2004 Jul;30(7):1549-55. PubMed PMID: 15210237
    CONCLUSION: The glistenings in AcrySof® IOLs were                      CONCLUSION: The birefringence of the 824C IOL could be a
    temperature dependent and confined to IOLs packaged                    source of error during polarization measurements of the
    in AcryPak® System folders and maintained at constant                  fundus or with instruments that transmit polarized light
    (body) temperatures. These findings are believed to                    through the IOL.
    be consistent with fluid formation within the acrylic optic,     36.   Oshika T, Santou S, Kato S, Amano S. Secondary closure of
    somehow related to the AcryPak® packaging system.                      neodymium:YAG laser posterior capsulotomy. J Cataract
30. Ayaki M, Nishihara H, Yaguchi S, Koide R. Surfactant                   Refract Surg. 2001 Oct;27(10):1695-7. PubMed PMID:
    induced glistenings: surface active ingredients in                     11687373
    ophthalmic solutions may enhance water entry into the                  CONCLUSION: Although IOL exchange surgery was
    voids of implanted acrylic intraocular lenses. J Long Term Eff         considered, a second Nd:YAG laser intervention successfully
    Med Implants. 2006;16(6):451-7. PubMed PMID: 17956212                  removed the proliferated lens materials and restored the
    CONCLUSION: The Diclod test group had a greater                        visual acuity. The glistenings were not the cause of the
    number of glistenings than the Rinderon test group. Both               reduced vision.
    drugs have similar anti-inflammatory properties and Diclod,      37.   Dogru M, Tetsumoto K, Tagami Y, Kato K, Nakamae
    unlike Rinderon, also contains the surfactant polysorbate.             K. Optical and atomic force microscopy of an explanted
    We proposed that the presence of surfactant, or other                  AcrySof®intraocular lens with glistenings. J Cataract Refract
    ingredient, in commercially available eyedrops may                     Surg. 2000 Apr;26(4):571-5. PubMed PMID: 10771232
    enhance the development of glistenings.                                CONCLUSION: The glistenings in the explanted AcrySof® IOL
31. Dick HB, Olson RJ, Augustin AJ, Schwenn O, Magdowski G,                were likely caused by temperature changes and not
    Pfeiffer N. Vacuoles in the Acrysof intraocular lens as factor         mechanical stress from folding.
    of the presence of serum in aqueous humor. Ophthalmic
References
38. Werner L, Storsberg J, Mauger O, Brasse K, Gerl R, Müller M,
    Tetz M. Unusual pattern of glistening formation on a
    3-piece hydrophobic acrylic intraocular lens. J Cataract
    Refract Surg. 2008 Sep;34(9):1604-9. PubMed PMID:
    18721729
    CONCLUSION: Analyses of the explanted IOL and the
    control IOL under differential scanning calorimetry, as well
    as by attenuated total reflection Fourier transform infrared
    spectroscopy, revealed slight differences between the IOLs.
39. Mönestam E, Behndig A. Impact on visual function from
    light scattering and glistenings in intraocular lenses, a
    long-term study. Acta Ophthalmol. 2011 Dec;89(8):724-8.
    doi: 10.1111/j.1755-3768.2009.01833.x. Epub 2010 Jan 8.
    PubMed PMID: 20064111
    CONCLUSION: Most patients in this case series operated 10
    years previously had severe glistenings and a high level
    of light scattering from their intraocular lenses. No
    detectable impact on BCVA, LCVA 10% and 2.5% was found.
40. Hayashi K, Hirata A, Yoshida M, Yoshimura K, Hayashi H.
    Long-term effect of surface light scattering and glistenings
    of intraocular lenses on visual function. Am J Ophthalmol.
    2012 Aug;154(2):240-251.e2. Epub 2012 May 23. PubMed
    PMID: 22633349
    CONCLUSION: At more than 10 years postoperatively, visual
    function, including contrast sensitivity, and ocular HOAs
    were comparable among eyes that received acrylic, silicone,
    and PMMA IOLs. Surface scattering and glistenings with the
    acrylic IOLs were not significantly correlated with visual
    function and optical aberrations.

© 2012 Novartis     12/12     NIQ12422SA
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