Eradication of posterior capsule opacification: documentation of a marked decrease in Nd:YAG laser posterior capsulotomy rates noted in an analysis of 5416 pseudophakic human eyes obtained postmortem

OBJECTIVE: (1) To report the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy rate (%) of eight rigid and foldable intraocular lens (IOL) designs in a series of 5416 pseudophakic human eyes obtained postmortem, accessioned in our center between January 1988 and January 2000. (2) To identify factors that are instrumental in reducing the incidence of posterior capsule opacification, (PCO, secondary cataract) and hence the need for Nd:YAG laser posterior capsulotomy. DESIGN: Comparative autopsy tissue analysis. PARTICIPANTS: A total of 5416 globes with posterior chamber intraocular lens (PC-IOLs) obtained postmortem received from Lions Eye Banks between 1988 and 2000. METHODS: Miyake-Apple posterior photographic technique. Special reference was given to the presence or absence of Nd:YAG laser posterior capsulotomy orifice on the posterior capsule of each eye. MAIN OUTCOME MEASURES: The Nd:YAG laser posterior capsulotomy rate (%) as of January 2000 was documented. In addition, the Nd:YAG laser posterior capsulotomy rate for each lens was plotted on a monthly basis for the same period, creating a computerized trend or "timeline" for each IOL style. RESULTS: Relatively high Nd:YAG laser posterior capsulotomy rates ranging from 20.3% to 33.4% were noted with four relatively older designs (high incidence of implantation between 1988 and the early 1990s). Four modern foldable IOLs manufactured from silicone and acrylic materials had significantly lower Nd:YAG laser posterior capsulotomy rates ranging from 0.9% (Alcon Acrysof) to 17.1%. The difference in Nd:YAG rates among the eight IOL designs was found to be significant (P < 0.0001, chi-square test). Comparing foldable versus rigid designs, the foldable IOLs were associated with a much lower Nd:YAG laser posterior capsulotomy rate (14.1% vs. 31.1%). CONCLUSIONS: By use of the six factors regarding surgical technique and IOL choice described in this article, we strongly believe that the overall incidence of PCO and hence the incidence of Nd:YAG laser posterior capsulotomy is now rapidly decreasing from rates as high as 50% in the 1980s to early 1990s. Surgical tools and IOLs are now available to bring these rates down to single digits. Careful application and use of these tools by surgeons can genuinely lead in the direction of virtual eradication of secondary cataract, the second most common cause of visual loss worldwide.     

Cumulative probability of neodymium: YAG laser posterior capsulotomy after phacoemulsification

PURPOSE: To retrospectively analyze the cumulative probability of neodymium:YAG (Nd:YAG) laser posterior capsulotomy after phacoemulsification and to evaluate the risk factors. SETTING: Ando Eye Clinic, Kanagawa, Japan. METHODS: In 3997 eyes that had phacoemulsification with an intact continuous curvilinear capsulorhexis, the cumulative probability of posterior capsulotomy was computed by Kaplan-Meier survival analysis and risk factors were analyzed using the Cox proportional hazards regression model. The variables tested were sex; age; type of cataract; preoperative best corrected visual acuity (BCVA); presence of diabetes mellitus, diabetic retinopathy, or retinitis pigmentosa; type of intraocular lens (IOL); and the year the operation was performed. The IOLs were categorized as 3-piece poly(methyl methacrylate) (PMMA), 1-piece PMMA, 3-piece silicone, and acrylic foldable. RESULTS: The cumulative probability of capsulotomy after cataract surgery was 1.95%, 18.50%, and 32.70% at 1, 3, and 5 years, respectively. Positive risk factors included a better preoperative BCVA (P =.0005; risk ratio [RR], 1.7; 95% confidence interval [CI], 1.3-2.5) and the presence of retinitis pigmentosa (P<.0001; RR, 6.6; 95% CI, 3.7-11.6). Women had a significantly greater probability of Nd:YAG laser posterior capsulotomy (P =.016; RR, 1.4; 95% CI, 1.1-1.8). The type of IOL was significantly related to the probability of Nd:YAG laser capsulotomy, with the foldable acrylic IOL having a significantly lower probability of capsulotomy. The 1-piece PMMA IOL had a significantly higher risk than 3-piece PMMA and 3-piece silicone IOLs. CONCLUSIONS: The probability of Nd:YAG laser capsulotomy was higher in women, in eyes with a better preoperative BCVA, and in patients with retinitis pigmentosa. The foldable acrylic IOL had a significantly lower probability of capsulotomy.     

Experimental neodymium:YAG laser damage to acrylic,poly(methyl methacrylate), and silicone intraocular lens materials

Purpose:To compare neodymium: YAG (Nd:YAG) laser effects on acrylic, silicone and poly(methyl methacrylate) (PMMA) intraocular lens (IOL) polymersMethods:Ten Nd: YAG laser exposures were produced in each of 6 implantation quality acrylic (Alcon MA60BM), silicone (Staar AQ1016), and PMMA (Alcon MC60BM) IOLs under identical conditions. Each polymer type was irradiated at 6 power settings (0.3, 0.5, 1.0, 1.5, 2.0, and 3.0 mJ) and at 2 focal points (midpoint of lens optic and on the posterior surface to which a cellophane membrane was affixed). The linear extent of the damage was measured using light microscopy,. Specimens exposed to 1.0 mJ were processed for scanning electron microscopy.Results:The damage threshold (≥ μm depth) was 0.3 mJ for silicone and 10 mJ for acrylic and PMMA IOLs. At the clinically relevant power levels, 10 to 20 mJ the depth of damage in the acrylic polymer was 11.9 to 30.5 times less than the depth in the silicone polymer. Similarly, the depth of damage in the PMMA polymer was 5.4 to 52.6 times less than the depth in the silicone polymer. The morphologic pattern of damage in the silicone IOL showed a deep, irregularly configured trough with meandering tendrils. Acrylic IOL damage morphology consisted of an ameboid-shaped entry site without radiating fracture and mild posterior penetration. Poly(methyl methacrylate) IOL damage consisted of a shallow focal trough with radiating fractures.Conclusions:The silicone IOL polymer had the lowest threshold for laser-induced damage and greater linear extension of damage than the PMMA and acrylic IOL polymers. Poly(methyl methacrylate) and silicone polymers exhibited collateral damage or ejected particulates adjacent to the entry site, whereas the acrylic polymer showed a discrete locus of damage.     

Influence of intraocular lens material on regeneratory posterior capsule opacification after neodymium:YAG laser capsulotomy

PURPOSE: To evaluate the influence of a neodymium:YAG (Nd:YAG) laser capsulotomy on the morphology and development of regeneratory opacification of the remaining surrounding posterior capsule. SETTING: Department of Ophthalmology, Medical School, University of Vienna, Vienna, Austria. METHODS: Standardized digital retroillumination photographs were taken immediately before and after Nd:YAG laser capsulotomy and at 1 week, 6 months, and 1 to 3 years in 38 eyes of consecutive patients. Changes in regeneratory posterior capsule opacification (PCO) and opacification around the capsulotomy opening were evaluated. The influence of the type of intraocular lens (IOL) material and design (acrylic, n = 8; hydrogel, n = 8; silicone open loop, n = 11; silicone plate haptic, n = 6; poly(methyl methacrylate) [PMMA], n = 5) was assessed. The state of the anterior vitreous surface was examined at the slitlamp in all eyes. RESULTS: In 8 of 17 eyes with a silicone IOL, reduced regeneratory PCO was observed. Massive pearl formation on the margin of the Nd:YAG capsulotomy was typical with silicone IOLs (8 eyes) but also occurred with PMMA IOLs. Eyes with acrylic IOLs had no change in regeneratory PCO after the capsulotomy. Three of 8 eyes with hydrogel IOLs had complete closure of the posterior capsulotomy opening. CONCLUSIONS: Neodymium:YAG laser capsulotomy induced changes in the development and morphology of regeneratory PCO. Silicone and PMMA IOLs led to significant pearl formation on the capsulotomy margin, often combined with a reduction of peripheral regeneratory PCO (silicone). Hydrogel IOLs led to a higher incidence of reclosure of the Nd:YAG capsulotomy opening.     

The experimental study of Nd: YAG laser injuring effects on intraocular lenses made by different materials

OBJECTIVE: To inquire the injuring effects of the Q-switched neodymium: yttrium aluminum garnet (Nd : YAG) laser on silicone, hydrogel (HEMA), acrylic, lathe cutting and cast molding polymethylmethacrylate (PMMA) intraocular lenses (IOLs). METHODS: The Nd : YAG of different energy was focused on the posterior surface of the IOL optic portion and shot in air and BSS separately. The percentages of IOL injuries were calculated, and the morphology of the IOL injuries was observed with a scanning electron microscope. RESULTS: Percentages of IOL injury: When the same energy of Nd : YAG laser was used, the injuring effects on the same kind of IOLs in air and in BSS were similar, while the laser energies of 0.5 mJ and 1.0 mJ were used, the injuring effects on different kinds of IOLs were significantly different, and when the energy of the laser was more than 1.5 mJ, the injuring effects were almost the same. Under different conditions, the morphology of the injury on different kinds of IOLs was different. CONCLUSIONS: (1) The sequence of resisting ability against Nd : YAG laser injury of different kinds of IOLs from strong to weak is: The lathe cutting PMMA IOL > acrylic IOL > cast molding PMMA IOL > HEMA IOL and silicone IOL. (2) The injuring effect of high energy Nd : YAG laser on rigid IOL is more severe than that on the soft IOL. (3) The size of IOL injuries is increased with the elevation of energy level of Nd : YAG laser.     

Neodymium:YAG capsulotomy rates following phacoemulsification with implantation of PMMA, silicone, and acrylic intraocular lenses

BACKGROUND AND OBJECTIVE: Posterior capsular opacification (PCO) is the most common visually disabling sequela of modern cataract surgery. Methods of reducing its incidence include the development of newer surgical techniques and intraocular lens (IOL) materials and designs. The aim of this study was to compare the incidence and time interval of development of PCO, and the requirement of laser capsulotomy in patients implanted with a polymethylmethacrylate (PMMA), silicone, or acrylic IOL. PATIENTS AND METHODS: The data of 340 consecutive patients who underwent phacoemulsification and implantation ofa PMMA, silicone, or acrylic intraocular lens were analyzed. The aim of this study was to compare the incidence and time interval of development of PCO, and the requirement of laser capsulotomy in patients implanted with a PMMA, silicone, or acrylic IOL. RESULTS: The incidence of PCO was found to be significantly less in the acrylic group (6.5% as compared to 21.74% and 26.6% in the PMMA and silicone groups, respectively; P = 0.01297 and 0.0039). Most patients (65%) exhibiting PCO in the PMMA group developed it within the first six months. In the silicone group, development of PCO was delayed. In 60% of patients, it appeared 18 months after surgery. Neodymium:YAG capsulotomy was required in 45% and 60% of patients developing PCO in the PMMA and silicone groups, respectively, while it was required in only 1 of the 4 patients developing PCO in the acrylic group. CONCLUSION: This study indicates that implantation of an acrylic IOL helps reduce the incidence of PCO as well as the need for Nd:YAG capsulotomy. PMMA IOLs require Nd:YAG capsulotomy earlier in the postoperative period as compared to silicone IOLs.     

Comparison of Nd : YAG capsulotomy rates following phacoemulsification with implantation of PMMA, silicone, or acrylic intra-ocular lenses in four European countries

PURPOSE: The aim of this study was to compare the incidence of Nd : YAG laser capsulotomy after cataract surgery according to the type of intra-ocular lens material (PMMA, silicone, hydrophilic acrylic, hydrophobic acrylic) implanted in four European countries (France, Italy, Germany, Spain). DESIGN: A retrospective record review. PARTICIPANTS: A review of 1525 patients (first operated eye), aged 50 to 80 years, operated on for cataract in 1996 or 1997 in 16 surgical centers (4 per country). METHODS: The study employed a retrospective cohort design. Charts were reviewed to collect information during at least a three-year period following cataract surgery to identify patients who underwent Nd : YAG laser capsulotomy postoperatively. MAIN OUTCOME MEASURES: Data on the type of intra-ocular lens implanted was extracted from the patient notes, as was the date and outcome of the Nd : YAG laser intervention. Kaplan-Meier survival curve analysis with the time to Nd : YAG laser was performed on the data. RESULTS A total of 1525 patients (first operated eye) were available for the study (n = 294 for hydrophilic acrylic, n = 384 for PMMA, n = 421 for hydrophobic acrylic, n = 426 for silicone). There was a highly statistically significant difference between the IOL groups for the incidence of posterior capsule opacification (p < 0.001) and for Nd : YAG laser treatment (p < 0.001). The mean delay of Nd : YAG laser treatment from the date of cataract operation was 2.48 years (+/-1.70, ranging from 0 to 5.88 years).The rate of Nd : YAG laser capsulotomy over the follow-up period was lowest in the hydrophobic acrylic group (7.1%), followed by silicone (16.2%), PMMA (19.3%) and hydrophilic acrylic (31.1%), respectively. CONCLUSIONS: A low incidence of posterior capsular opacification (PCO) and Nd : YAG laser treatment was detected in hydrophobic acrylic IOLs in comparison to three other types of IOLs implanted in a large cohort of persons with age-related cataract. Choice of IOL type may reduce the need for Nd : YAG laser treatment, although further research on the reasons for this is needed.     

Comparison of Nd : YAG capsulotomy rates following phacoemulsification with implantation of PMMA,silicone, or acrylic intra-ocular lenses in four European countries

PURPOSE The aim of this study was to compare the incidence of Nd : YAG laser capsulotomy after cataract surgery according to the type of intra-ocular lens material (PMMA, silicone, hydrophilic acrylic, hydrophobic acrylic) implanted in four European countries (France, Italy, Germany, Spain). DESIGN A retrospective record review. PARTICIPANTS A review of 1525 patients (first operated eye), aged 50 to 80 years, operated on for cataract in 1996 or 1997 in 16 surgical centers (4 per country). METHODS The study employed a retrospective cohort design. Charts were reviewed to collect information during at least a three-year period following cataract surgery to identify patients who underwent Nd : YAG laser capsulotomy postoperatively. MAIN OUTCOME MEASURES Data on the type of intra-ocular lens implanted was extracted from the patient notes, as was the date and outcome of the Nd : YAG laser intervention. Kaplan-Meier survival curve analysis with the time to Nd : YAG laser was performed on the data. RESULTS A total of 1525 patients (first operated eye) were available for the study (n = 294 for hydrophilic acrylic, n = 384 for PMMA, n = 421 for hydrophobic acrylic, n = 426 for silicone). There was a highly statistically significant difference between the IOL groups for the incidence of posterior capsule opacification (p &lt; 0.001) and for Nd : YAG laser treatment (p &lt; 0.001). The mean delay of Nd : YAG laser treatment from the date of cataract operation was 2.48 years (±1.70, ranging from 0 to 5.88 years).The rate of Nd : YAG laser capsulotomy over the follow-up period was lowest in the hydrophobic acrylic group (7.1%), followed by silicone (16.2%), PMMA (19.3%) and hydrophilic acrylic (31.1%), respectively. CONCLUSIONS A low incidence of posterior capsular opacification (PCO) and Nd : YAG laser treatment was detected in hydrophobic acrylic IOLs in comparison to three other types of IOLs implanted in a large cohort of persons with age-related cataract. Choice of IOL type may reduce the need for Nd : YAG laser treatment, although further research on the reasons for this is needed.     

Secondary closure of neodymium:YAG laser posterior capsulotomy.

A 67-year-old man reported reduced vision after cataract surgery and neodymium:YAG (Nd:YAG) laser posterior capsulotomy. The diagnosis was complicated due to severe glistenings within the optic of an acrylic foldable intraocular lens (IOL), proliferation of lens epithelial remnants over the capsulotomy opening, and presumed vitreous opacity. Although IOL exchange surgery was considered, a second Nd:YAG laser intervention successfully removed the proliferated lens materials and restored the visual acuity. The glistenings were not the cause of the reduced vision.     

Nd:YAG capsulotomy rates after use of the AcrySof acrylic three piece and one piece intraocular lenses

BACKGROUND/AIM: Acrylic lens size and shape may influence the rate of posterior capsule opacification (PCO) and need for Nd:YAG capsulotomy. The aim of this study is to compare the Nd:YAG capsulotomy rate of the three piece acrylic/PMMA AcrySof MA series lens with the one piece acrylic AcrySof SA series lens. METHODS: 434 eyes of 329 patients who had cataract extraction and implantation of one of four types of intraocular lenses (IOLs) were evaluated for rate of Nd:YAG capsulotomy. 176 eyes received the acrylic AcrySof MA30AC IOL, 71 eyes the acrylic AcrySof MA60AC IOL, 45 eyes the acrylic AcrySof SA30AL IOL, and 142 eyes the acrylic AcrySof SA60AT IOL. RESULTS: The rates of Nd:YAG capsulotomy with the three piece IOL (MA30AC/MA60AC) and the one piece IOL (SA30AL/SA60AT) were 1.2% and 2.1% at 6 months, 2.8% and 5.9% at 12 months, and 3.6% and 7.5% at 24 months, respectively. The incidence of Nd:YAG capsulotomy was higher in patients who received the one piece IOL (p=0.01, log rank test). There was no difference in Nd:YAG capsulotomy rates when comparing lens optic size, age, sex, history of pars plana vitrectomy, and diabetes mellitus. CONCLUSIONS: This study shows a greater incidence of Nd:YAG capsulotomy in patients who receive one piece acrylic AcrySof lenses when compared to those who receive three piece acrylic AcrySof lenses.     

两种Nd:YAG激光后囊切开方式对不同材料人工晶状体损伤的观察

目的观察Nd:YAG激光后囊膜切开方式对不同材料的人工晶体(IOL)损伤的情况。方法对86例(124只眼)IOL眼晶状体后囊膜混浊(posterior capsule opacity,PCO)患者随机分为两组行Nd:YAG激光后囊膜切开术。A组64眼采用环行切开后推膜瓣法,人工晶体包括:PMMA23眼、疏水性丙烯酸26眼、硅凝胶15眼。B组60眼行十字形切开法,人工晶体包括:PMMA21眼、疏水性丙烯酸25眼、硅凝胶14眼。术前术后常规眼前段检查、测视力、眼压。结果截囊成功率100%。发生IOL损伤16眼,其中A组6眼(9.38%),B组10眼(16.67%),两种方式对相同材料的人工晶体损伤的机率相似(均p>0.05),不同材料的耐受强弱依次为PMMA、疏水性丙烯酸、硅凝胶,均为轻度损伤。结论两种方式对不同材料损伤的机率依次为硅凝胶、疏水性丙烯酸、PMMA,但环行切开后推膜瓣法可以减少Nd:YAG激光后囊膜切开术IOL损伤机率。     

Intraocular lens materials and styles: A review

Biomaterial science has lead to the development of a variety of foldable intraocular lens (IOL) biomaterials. This literature review examines these lenses from both a basic science and a clinical perspective. By most parameters, hydrogel, soft acrylic and silicone IOL are better than polymethylmethacrylate (PMMA) lenses.
Plate haptic silicone IOL have the lowest incidence of cystoid macula oedema and posterior capsule opacification, but these lenses require an intact anterior capsularhexis and posterior capsule. Yttrium aluminium garnet (YAG) laser capsulotomy must be delayed at least 3 months to avoid posterior lens dislocation. Silicone has the lowest threshold for YAG laser damage of all IOL materials and also adheres irreversibly to silicone oil with subsequent optical impairment. Three piece silicone IOL with polypropylene haptics have a higher incidence of decentration, pigment adherence and capsule opacification compared with PMMA haptics. Hydrogel lenses are very biocompatible and resistant to YAG laser damage, but pigment adheres to the surface more readily than PMMA. Soft acrylic IOL unfold slowly, resulting in controlled insertion, but it is possible to crack the lens and some lenses develop glistenings due to water accumulation.
There are significant socioeconomic implications to the large differences in posterior capsule opacification rates between the various biomaterials and the lens styles.     

Posterior capsule opacificationin eyes with a silicone or poly(methyl methacrylate) intraocular lens

Purpose:To evaluate the effect of poly(methyl methacrylate) (PMMA) and silicone intraocular lenses (IOLs) on posterior capsule opacification (PCO) after cataract surgery.Setting:Kangnam St. Mary's Hospital, Seoul, Korea.Methods:This retrospective study comprised 48 patients (54 eyes) who hadneodymium:YAG (Nd:YAG) laser posterior capsulotomy from March 1995 to December 1997. All operations were performed by 1 surgeon using the same technique except for incision method.Results:Mean interval from cataract surgery to Nd:YAG capsulotomy was 31 months in the PMMA group and 15 months in the silicone group. The difference between groups was statistically significant (P = .0002). The ratio of Elschnig pearl to fibrosis type PCO was 16:6 in the PMMA group and 14:18 in the silicone group Mean total Nd:YAG laser energy used was 256 mJ in the PMMA group and 309 mJ in silicone group. However, the damage caused by the laser was more severe and more common in the silicone group.Conclusion:Silicone IOLs induced PCO faster than PMMA IOLs, with fibrosis the most common type in the silicone group. Precautions should betaken to prevent damage during Nd:YAG laser capsulotomy in eyes with a silicone IOL.     

Update on fixation of rigid and foldable posterior chamber intraocular lenses. Part II: Choosing the correct haptic fixation and intraocular lens design to help eradicate posterior capsule opacification.

PURPOSE: Posterior capsule opacification (PCO) is one of the most common complications of cataract surgery, and there is an urgent need to reduce its incidence. Its main treatment, neodymium:YAG (Nd:YAG) laser posterior capsulotomy, may be associated with significant morbidity and is expensive. In this study, the authors ascertain the effect of posterior chamber intraocular lens (PC-IOL) fixation and various IOL designs (rigid polymethyl methacrylate [PMMA] optic and small-incision foldable designs) on the pathogenesis of PCO. DESIGN: Prospective analysis of pseudophakic eyes obtained postmortem. PARTICIPANTS: A total of 3493 eyes with PC-IOLs obtained postmortem and received between 1984 and 1998. METHODS: Miyake-Apple posterior photographic technique. MAIN OUTCOME MEASURES: Peripheral Soemmering's ring, central PCO in the visual axis, and eyes that have had Nd:YAG laser posterior capsulotomy were analyzed and scored, and these findings were correlated with the type of fixation and IOL design. RESULTS: The degree of formation of peripheral Soemmering's ring was not influenced by IOL fixation. The acrylic design revealed relatively low Soemmering's ring scores. In contrast, central PCO and Nd:YAG laser capsulotomy scores were consistently influenced by fixation. The scores were significantly lower in eyes with in-the-bag fixation. The bag-bag fixated acrylic-PMMA design and the three modern silicone IOL designs analyzed in this study had less central PCO and lower posterior capsulotomy scores than did the PMMA IOLs. CONCLUSIONS: The formation of peripheral PCO (the Soemmering's ring), the precursor of clinically significant, vision-threatening PCO, is not significantly influenced by the haptic fixation pattern. It is much more dependent on the quality and thoroughness of surgical cortical cleanup. Reduction of Soemmering's ring is an important goal because the retained regenerative cortical cells within this lesion are the cells of origin of PCO. The acrylic IOL design was associated with a lessor amount of peripheral Soemmering's ring as compared with all other designs. In sharp contrast to peripheral PCO, fixation of the IOL was a highly significant factor affecting the formation and quantity of central PCO-the clinically significant opacity behind the IOL optic, measured in this series either by scoring an intact retro-optical membrane or by documenting the presence of a Nd:YAG laser posterior capsulotomy orifice. The quantity of central PCO was consistently much lower in eyes with in-the-bag fixated IOLs compared with lenses with one or both haptics out of the bag. This is best explained by the fact that secure in-the-bag fixation positions the IOL optic in the best possible position to create a barrier effect. The lowest PCO rates were generally noted with the acrylic and modern silicone IOL designs.     

Posterior capsule opacification and neodymium: YAG capsulotomy rates with AcrySof acrylic and PhacoFlex II silicone intraocular lenses

PURPOSE: To compare the incidence and severity of posterior capsule opacification (PCO) and neodymium:YAG (Nd:YAG) capsulotomy rates between AcrySof(R) MA30BA acrylic (Alcon) and PhacoFlex(R) II SI-40NB silicone (AMO) intraocular lenses (IOLs). SETTING: Outpatient Cataract Surgery Center, TLC Eyecare and Laser Center, Jackson, Michigan, USA. METHODS: AcrySof and PhacoFlex II IOLs were implanted in fellow eyes of 156 patients requiring bilateral cataract extraction. The patients were followed for a mean of approximately 3 years for the incidence and severity of PCO and the Nd:YAG capsulotomy rates. RESULTS: Of the 63 eyes that were free of PCO throughout the study, 42 had the AcrySof IOL and 21 had the PhacoFlex II IOL. Of eyes that developed PCO, the mean severity in the AcrySof group was 16% less than that in the PhacoFlex II group. Of the 50 eyes that had an Nd:YAG capsulotomy, 17 were in the AcrySof group and 33 were in the PhacoFlex II group. All differences between groups were statistically significant (P<.05). CONCLUSION: The AcrySof MA30BA IOL was associated with less PCO proliferation and thus fewer Nd:YAG laser posterior capsulotomies than the PhacoFlex II SI-40NB IOL.     

Effect of four different intraocular lenses on posterior capsule opacification

AIM: To evaluate the impact of 4 different intraocular lenses (IOLs) on posterior capsule opacification (PCO) by comparing the neodymium: yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy rates. METHODS: This retrospective study included 4970 eyes of 4013 cataract patients who underwent phacoemulsification and IOL implantation between January 2000 and January 2008 by the same surgeon at one clinic. Four different IOLs were assessed. The outcome parameter was the incidence of Nd:YAG laser posterior capsulotomies. RESULTS: An Nd:YAG laser posterior capsulotomy was performed in 153 (3.07%) of the 4970 eyes. The mean follow-up time was 84mo for all of the IOL groups. The percentage of eyes developing PCO was significantly greater for the acrylic hydrophilic IOLs than for the hydrophobic IOLs, although eyes with acrylic hydrophilic IOLs did not require Nd:YAG laser capsulotomy as soon as eyes with acrylic hydrophobic IOLs. There was no difference between the long-term PCO rates when 1- and 3-piece acrylic hydrophobic IOLs were compared or when IOLs made of the same material but with different haptic angles were compared. CONCLUSION: In this study, eyes with acrylic hydrophilic IOLs were more likely to develop PCO than those with acrylic hydrophobic IOLs. The lens design (1-piece versus 3-piece and varying haptic angles) did not affect the PCO rate.     

Neodymium:YAG laser interaction with Alcon IOGEL hydrogel intraocular lenses: an in vitro toxicity assay

The objective of this study was to determine the potential toxicity generated by the interaction of the Nd:YAG laser and Alcon IOGEL intraocular hydrogel lens material. The IOGEL lens is composed of poly 2-hydroxyethylmethacrylate, containing 38% water, previously shown to be highly biocompatible in a wide range of tissue culture and implantation experiments. In this study, intraocular lenses (IOLs) immersed in serum-free cell culture medium were purposely exposed to exaggerated doses of laser energy to cause extensive damage. An IOLAB polymethylmethacrylate (PMMA) lens served as a control lens material. The resultant solutions were assayed for cytotoxicity in a bioassay system using fourth passage human corneal endothelial cells. No cytotoxicity was seen in the bioassay for the IOGEL hydrogel IOLs or the PMMA control IOL at any laser range/dosage tested over a 72-hour incubation period. Hydrogel lenses exhibited decreasing yellowing with decreasing energy levels, and no lens discoloration was apparent at the lowest level of irradiation, 5 mJ/50 laser bursts; the PMMA control lens exhibited moderate yellowing at 15 mJ/50 bursts. Lens marking was moderate for all IOGEL IOLs; the PMMA lens marking was severe at the power level tested.     

Posterior capsule opacification and Nd:YAG capsulotomy rates after implantation of silicone,hydrogel and soft acrylic intraocular lenses: a two-year follow-up study

PURPOSE: To compare the posterior capsule opacification (PCO) and neodymium:YAG (Nd:YAG) laser posterior capsulotomy rates associated with three different posterior chamber foldable intraocular lenses (IOL). METHODS: We retrospectively evaluated the rates of PCO and Nd:YAG laser capsulotomy in 1150 eyes two years after standard phacoemulsification with a no-stitch 3.5mm clear corneal incision (CCI) and in-the-bag implantation of one of three types of IOL: 190 eyes received a one-piece round-edged hydrogel IOL (Hydroview H60M, Bausch & Lomb); 475 eyes a three-piece round-edged silicone IOL (AMO PhacoFlex SI-40NB, Allergan); 485 eyes a three-piece square-edged soft acrylic lens (AcrySof MA60MA, Alcon). RESULTS: The PCO and Nd:YAG laser capsulotomy rates were respectively 43.15% and 20.5% in the Hydroview H60M group, 27.57% and 9.68% in the AMO PhacoFlex SI-40NB group, 10.5% and 2.47% in the AcrySof MA60MA group. CONCLUSIONS: PCO and Nd:YAG laser capsulotomy rates were significantly higher in the Hydroview H60M group and significantly lower with the AcrySof MA60MA lenses, which combine a bioactive constitutive material with the square-edged optic design.     

Nd:YAG laser capsulotomy rates following implantation of square-edged intraocular lenses: polymethyl methacrylate versus silicone versus acrylic

Objective: To study the influence of square-edged intraocular lenses (lOLs) on the development of posterior capsule opacification (PCO) and the requirement for laser capsulotomy.Design: Retrospective study.Participants: Three hundred seventy-seven eyes of 377 patients were included.Methods: All these patients underwent phacoemulsification and implantation of square polymethyl methacrylate (PMMA) (Aurolab), silicone (Tecnis Z9000), acrylic hydrophobic (AcrySof MA60AC and Sensar Optiedge), or acrylic hydrophilic (Akreos Adapt) lOLs with a minimum of 2 years’ follow-up. Only those cases in which Nd:YAG laser capsulotomy had been performed for visually significant PCO were evaluated.Results: Three hundred seventy-seven eyes of 377 patients were included in the study. Follow-up duration ranged from 24 to 54 (mean 40.27, SD 8.42) months. The incidence of PCO requiring Nd:YAG laser capsulotomy was found to be significantly less in the silicone lens group: 1.4% as compared with an incidence of 11.7% in the PMMA lens group (p = 0.018). In the square-edged acrylic group, visually significant PCO requiring Nd:YAG laser capsulotomy was observed in 3.6%, 4.8%, and 6.8% of eyes implanted with AcrySof MA60AC, Sensar Optiedge, and Akreos Adapt lOLs, respectively. In 5 of the 7 eyes (71.4%) exhibiting PCO in the PMMA group, the condition developed within the first 6 months. In the silicone and acrylic group, development of PCO was delayed.Conclusions: The rate of visually significant PCO as well as the need for Nd:YAG laser capsulotomy is influenced by IOL biomaterial in addition to square edge. It is significantly delayed with square-edged foldable acrylic and silicone lOLs compared with square-edged PMMA IOLs.     

Neodymium:YAG laser posterior capsulotomy after implantation of AcrySof intraocular lenses

PURPOSE: To report the incidence of neodymium:YAG (Nd:YAG) laser posterior capsulotomy after phacoemulsification and implantation of AcrySof (Alcon) intraocular lenses (IOLs). SETTING: Private practice, Wolfe Clinic, Marshalltown, Iowa, USA. METHODS: A retrospective diagnosis and procedure code review of 12419 consecutive cases having phacoemulsification and AcrySof IOL implantation from January 1995 through December 2002 was performed. The outcome parameter was the incidence of Nd:YAG laser posterior capsulotomies. RESULTS: An Nd:YAG laser posterior capsulotomy was performed in 763 (6.1%) of the 12419 cases. The incidence of posterior capsulotomy was approximately 1% at 1 year, increasing in linear fashion by approximately 1% to 2% per year. CONCLUSIONS: The Nd:YAG laser posterior capsulotomy rate after implantation of AcrySof IOLs was relatively low; the cumulative rate was approximately 1% to 2% new cases per year over a 7-year period, with a plateau suggested at year 6.