Intraocular Lens Opacification Following Silicone Oil Endotamponade

BACKGROUND AND OBJECTIVE

To report cases with intraocular lens (IOL) opacification following silicone oil (SO) endotamponade.

PATIENTS AND METHODS

Medical charts of 32 eyes with IOL opacification were evaluated retrospectively. All eyes had rhegmatogenous retinal detachment and had a history of previous hydrophilic acrylic IOL implantation. All patients underwent vitrectomy with SO endotamponade. Clinical features of all cases and the results of histochemical evaluation of explanted IOLs were reported.

RESULTS

The mean duration of SO endotamponade was 4.6 ± 2.0 months. The mean follow-up was 67.0 ± 23.5 months. The interval between phacoemulsification surgery and IOL opacification was 27.4 ± 18.3 months. With the exception of two eyes, all IOL opacification was detected during the follow-up period after SO removal. IOL exchange was performed in 12 eyes (37.5%). Histochemical analysis revealed significant calcification mostly on the surface of explanted IOL optics.

CONCLUSION

Vitreoretinal surgeons should be aware of that some hydrophilic IOLs may have the potential of opacification following SO endotamponade. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:37-43.].

[Chemical microanalysis of mineral deposits on explanted hydrophilic acrylic intraocular lenses]

AIM

to perform chemical microanalysis of mineral deposits on the surface of explanted hydrophilic acrylic intraocular lenses (IOL).

MATERIAL AND METHODS

Two soft IOLs made of hydrophilic acryl (one, however, hydrophobic surface coated) and explanted 3 and 6 years after implantation were examined by scanning electron microscopy (EVO LS10, "Karl Zeiss", Germany). Chemical composition of the lens surface was studied using an energy-dispersive spectrometer (EDS X-Max50, Oxford, Great Britain).

RESULTS

Chemical microanalysis allowed identification of the deposits, which turned out to be non-stoichiometric hydroxylapatite (also, hydroxyapatite (HA)) crystals with zinc impurity (up to 1.4%weight).

CONCLUSION

The two samples represent two stages of a single process. The early stage is associated with newly formed HA crystals that are unable to cause any significant changes to the lens surface. However, as spherocrystals grow, they exert a crystallization effort that moves their growth centers apart with subsequent lens rupture and deformation. Crystal morphology undergoes dynamic changes: while primary (newly formed) crystals are sheaf-like, mature are spheres. A growing HA is non-stoichiometric. Zinc abundance accounts for appearance of its separate mineral phase. Hydrophilic properties of acrylic polymer determine its high affinity for HA crystals. Hydrophobic coating (sample no.1) does not completely prevent lens opacification due to mineral deposits on its surface.

[Analyzing causes for opacification of acrylic IOLs]

AIM

to study the nature of intraocular lens (IOL) opacification depending on the patient's ocular status and general condition.

MATERIAL AND METHODS

A total of 9 patients (9 eyes) with 3-6 year history of progressive IOL opacification were enrolled. All the IOLs were acrylic (either hydrophilic--7 cases, or hydrophobic--2 cases). Two patients had their IOLs exchanged due to opacification. Six patients earlier underwent glaucoma surgery. Two patients were type 2 diabetic. Slit lamp biomicroscopy and optical microscopy were used for IOL examination.

RESULTS

The surface of hydrophilic acrylic lenses appeared bumpy because of multiple variously shaped translucent granules separated by a chaotic network of furrows and microfractures and located predominantly in the optic zone. In a more severe case, a bowl-shaped impression was observed in the area of opacification. Surface changes of hydrophobic acrylic lenses were in the form of isolated and confluent glistening formations (microcavities).

CONCLUSION

Signs of IOL degradation develop over a long period of time (3-6 years, in our experience) and mostly involve the anterior surface of the lens optic. Ocular comorbidity, glaucoma in particular, as well as other surgery and/or therapeutic treatment following IOL implantation may contribute to its opacification. Analysis of published data and own observations suggest that hydrophobic IOLs should be preferred in patients with concomitant diseases, especially diabetes mellitus. Granular deposits, if accumulate, may lead to deformation of the lens optic, as confirmed by the bowl-like impression in one of the explanted hydrophilic IOLs.

Two-year results of cataract extraction with implantation of the hydrophilic acrylic B-lens

PURPOSE

To evaluate the safety and efficacy of a hydrophilic acrylic intraocular lens (B-Lens((R)), Hanita, Israel) during a 2-year follow-up period.

SETTING

Department of Ophthalmology, Meir Hospital, Sapir Medical Center, Kfar-Saba, Israel.

PATIENTS & METHODS

Slit lamp biomicroscopy, refraction, visual function and patient satisfaction were recorded in 147 patients at 1 week, and at 1, 3, 12, and 24 months after surgery.

RESULTS

Nine cases (6%) were associated with partial rupture of the superior haptic intraoperatively, which did not preclude in-the-bag centration of the IOL in all cases. Postoperative complications were mild or reversible and rarely observed. The posterior capsule opacification (PCO) rate increased considerably (from 0.35 to 0.80) from 1 to 2 years but was for the most clinically insignificant; 16 of the 90 cases (18%) with PCO at 2 years had clinically significant opacification of the posterior capsule. No IOL discoloration was observed. BCVA stabilized by the third month and refraction was at the predicted level at two years. Eighty-one of 91 cases (89%) had BCVA equal to or more than 20/40 and 43 of 91 (47%) gained a BCVA of 20/20 at two years.

CONCLUSION

Hydrophilic acrylic B-Lens((R)) implantation is safe and effective for patients with cataract.

A New Classification of Calcification of Intraocular Lenses

OBJECTIVE

To define and classify the major types of intraocular lens (IOL) calcification.

DESIGN

Retrospective observational case series with clinicopathologic correlation.

PARTICIPANTS

More than 400 IOLs explanted because of opacification.

METHODS

The authors reviewed the clinical information and histologic findings of all IOLs that had been explanted because of opacification or calcification of the IOLs accessioned in their laboratory between January 1999 and December 2004.

MAIN OUTCOME MEASURE

The proposed mechanism that led to calcification of each IOL design.

RESULTS

Three major types of calcification were identified: (1) primary calcification, (2) secondary calcification, and (3) false-positive calcification or pseudocalcification. The primary form refers to calcification that is inherent in the IOL, that is, is based on possible inadequate formulation of the polymer, fabrication of the IOL, or issues with its packaging process. The calcification presumably occurs in otherwise normal eyes and generally is not associated with preexisting diseases. The secondary form refers to deposition of calcium onto the surface of the IOL most likely the result of environmental circumstances (e.g., changes in the aqueous milieu surrounding the implanted IOL associated with preexisting or concurrent diseases or indeed any condition that has disrupted the blood-aqueous barrier). By definition, it is not related to any problem with the IOL itself. The false-positive or pseudocalcification refers to those cases in which other pathology is mistaken for calcification or false-positive staining for calcium occurs.

CONCLUSIONS

When evaluating the pathogenesis and nature of IOL calcification in or on any given design, one should categorize it according to these types. Primary calcification is IOL related and the IOL should be withdrawn or modified to correct the problem. After the cause is identified and the lens is implanted again, patients should be followed up for up to 2 years to be sure the problem is alleviated. Secondary calcification is by definition not IOL related; it may occur with virtually all IOL designs implanted under various adverse circumstances. No IOL, hydrophilic or hydrophobic, is immune to secondary calcification. The false-positive form is recognized readily in the laboratory and this erroneous diagnosis is avoided.

Analysis of aqueous humor calcium and phosphate from cataract eyes with and without diabetes mellitus

Purpose

To compare the levels of calcium and phosphorus in the aqueous humor and serum of diabetics and non-diabetics.

Methods

We divided patients into two groups: seventy-six non-diabetic cataract patients and fifty-two diabetic cataract patients. The diabetic group was divided again into three subgroups: twenty-six patients with no diabetic retinopathy, thirteen patients with non-proliferative diabetic retinopathy, and thirteen patients with proliferative diabetic retinopathy. The authors compared the levels of calcium and phosphorus in the serum and aqueous humor of cataract patients. Statistic analysis was performed to form two comparisons: 1) a comparison between non-diabetics and diabetics and 2) a comparison among non-diabetics and the three subgroups of diabetics.

Results

In serum, calcium levels did not statistically differ between non-diabetics and diabetics. The phosphorus level was also not significantly different. In the aqueous humor, however, while calcium levels did not differ significantly, the phosphorus levels in diabetics were considerably higher than those in non-diabetics. When non-diabetics were compared to the three diabetic subgroups, calcium levels did not differ in serum or aqueous humor, but the phosphorus levels in diabetics with proliferative diabetic retinopathy were significantly higher than those in non-diabetics, diabetics without diabetic retinopathy, and diabetics with non-proliferative diabetic retinopathy.

Conclusions

The level of phosphorus in the aqueous humor and serum of diabetics was significantly increased, especially in diabetics with proliferative diabetic retinopathy. This result may be related to hydrophilic acrylic IOL opacification. Future studies regarding the pathogenic role of a high concentration of aqueous humor and serum phosphorus are required.

Effect of Ultraviolet B Radiation on the Absorption Characteristics of Various Intraocular Lenses

BACKGROUND

The aim of this study was to determine the effect of ultraviolet B (UVB) exposure on UV filters of various intraocular lenses (IOLs).

METHODS

Eight samples each of the hydrophobic acrylic, hydrophilic acrylic and silicone IOLs were used. Four IOLs of each type was selected randomly as the control group while the remaining four IOLs of each type were exposed to a UVB dose of 1.4 J/cm(2) (2.40 mW/cm(2)) for 9.45 min, two times with a 4-week interval. IOLs were evaluated for any sign of opacification under microscope weekly. After a follow-up period of 16 weeks, spectrometry for UV filter absorption rates, scanning electron microscopy for deposit formation and energy dispersive X-ray analysis for elemental composition were performed for all IOLs, and findings of the control group IOLs were compared with those of the UVB-exposed IOLs. All these procedures were done at the Department of Ophthalmology, Faculty of Medicine, Dokuz Eylul University.

RESULTS

All the IOLs were free of any opacification during the follow-up period. Spectrometric analysis of their UV filters revealed a change in absorption rates in the hydrophilic acrylic and silicone IOLs compared to the control IOLs of the same type. Only the hydrophobic acrylic IOLs preserved the same UV absorption curve after UVB exposure.

CONCLUSION

The pathogenesis of IOL opacification is still undetermined. Some reports claimed that the UV light was the responsible factor. Our experimental study revealed that high doses of UVB did not cause any opacification though they impaired the function of UV filters of the hydrophilic acrylic and silicone IOLs.

Two opacification patterns of the same hydrophilic acrylic polymer: case reports and clinicopathological correlation

We report 2 intraocular lenses (IOLs) manufactured from the same hydrophilic acrylic polymer by Ioltech that developed optic opacification. In both cases, the postoperative course after implantation of the IOLs was complicated by significant inflammatory reaction with fibrin formation in the anterior chamber. Pathologic analyses of the explanted IOLs were consistent with dystrophic calcification leading to optic opacification, but the pattern was different between the 2 IOL designs. Patient-related factors might have been responsible for this complication.

Intraocular lens haptic fracturing with the neodymium:YAG laser

PURPOSE

To determine the neodymium:YAG (Nd:YAG) laser energy threshold to fracture the haptic of various currently marketed intraocular lenses.

SETTING

Dokuz Eylul University, Ophthalmology Department, Izmir, Turkey.

METHODS

Four haptic materials-poly(methyl methacrylate) (PMMA), hydrophobic acrylic, hydrophilic acrylic, and polyvinylidene fluoride-were tested. The intraocular lenses (IOLs) were grouped according to haptic material. Each group comprised 9 IOLs. Beginning laser energy was 4 mJ. If no crack was noted, energy was increased by 0.5 mJ at every 20 shots and the procedure continued until a fracture was noted. If the fracture could not be developed despite reaching an energy level of 10 mJ, the procedure was terminated. Statistical analysis was performed to determine the differences within groups.

RESULTS

Hydrophobic acrylic and polyvinylidene fluoride haptics required higher energy and more laser shots to create a fracture than hydrophilic acrylic and PMMA haptics.

CONCLUSIONS

Neodymium:YAG laser haptic fracturing can be a viable option to cut the fibrosed haptic before explanting any IOL. It was demonstrated in vitro that it is easier to fracture hydrophilic acrylic and PMMA haptics than hydrophobic acrylic and polyvinylidene fluoride haptics.

Role of silicon contamination on calcification of hydrophilic acrylic intraocular lenses

PURPOSE

To verify the presence of the element silicon on hydrophilic acrylic intraocular lenses (IOLs) explanted because of calcification.

DESIGN

Interventional case series with clinicopathological correlation.

METHODS

Twenty explanted IOLs with surface deposits (MemoryLens), and 20 with deposits mostly within their optic substance (SC60B-OUV and Aqua-Sense; 10 each) were used. After gross, microscopic, and histochemical analyses to confirm the presence of deposits, the lenses underwent scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS) for elemental composition, on the external surface of MemoryLens IOLs, and on the surface and internal substance of SC60B-OUV and Aqua-Sense IOLs. The weight percentage of the element silicon was obtained at the level of deposits, and at adjacent deposit-free areas in all lenses.

RESULTS

Scanning electron microscopy (SEM) coupled with EDS confirmed that the composition of the deposits was calcium/phosphate in all cases. The element silicon was found in all 40 lenses, on all areas analyzed. The silicon weight percentage was higher at the level of the deposits. The presence of aluminum on five MemoryLens IOLs, and in most of the SC60B-OUV and Aqua-Sense lenses might be related to scattering from the aluminum mounting stubs used for surface analyses.

CONCLUSIONS

Silicone compounds have been implicated in the calcification of another hydrophilic acrylic design (Hydroview). They may also have a role in the calcification of other hydrophilic acrylic IOLs. Further investigation on the relationship between the presence of the element silicon and the silicone compounds found on calcified hydrophilic acrylic lenses is necessary.

[Opacification of a hydrophilic acrylic intraocular lens]

PURPOSE

To report pathological and histochemical analysis of an explanted opacified hydrophilic acrylic intraocular lens.

PATIENTS

and method: A hydrophilic acrylic intraocular lens--Orion IFP3D6--was explanted 2 years after routine phacoemulsification because of its opacification associated with significant visual impairment (20/40). The intraocular lens was examined by gross and light microscopy. Full-thickness cut sections of the lens were stained with 1% alizarin red (a special stain for calcium).

RESULTS

Microscopic analyses revealed the presence of granules of various sizes distributed in a line parallel to the anterior and posterior curvatures of the lens. The granules stained positively for alizarin red.

CONCLUSION

Such opacification has been described with the SC60B-OUV, MDR Inc., which is also a one-piece foldable-design intraocular lens (28% hydrophilic material). The opacification of the intraocular lens occurred over various periods after surgery. Forty percent of these lenses have been explanted. Microscopic and histochemical evaluation of these intraocular lenses revealed the same type of granulation deposits within the lenses. The origin and mechanism of the opacification are still not fully understood.

Calcification postopératoire des lentilles intraoculaires acryliques hydrophiles : aspects cliniques et pathologiques

PURPOSE

The aim of this study was to evaluate the clinical aspects of ten eyes with calcified hydrophilic acrylic intraocular lenses and pathological data obtained from seven explanted lenses.

MATERIAL AND METHODS

Forty-seven eyes of 40 patients received the same implant in the first 6-month period of 2001. Ten eyes showed intraocular lens opacification detected 6-18 months after the operation: seven lenses were explanted and three were left in place because they were not causing a decrease in visual acuity or glare at light. Five of ten eyes were diabetic. The explanted lenses were examined under the light microscope and the electron microscope. The elemental analysis of the lens surfaces was made by energy dispersive spectrometry.

RESULTS

The light microscopy showed an irregular surface covered by a gray-white opacity. The electron microscopy detected multiple granulations on the front and back surfaces of the lenses including some portions of the haptics. The size and density of these granulations were smaller on the back surface. The energy dispersive spectrometry showed the presence of calcium and phosphate on both surfaces. The spikes of calcium and phosphate were smaller for the back surface of the lenses.

DISCUSSION

Calcification was predominantly seen on the surfaces that were in contact with aqueous not covered with anterior capsule. Half (5/10) of the cases were diabetic even though 18% of all patients receiving this lens were diabetic. The presence of diabetes is very common in other series. These data suggest the role of a metabolic factor influencing the milieu of the lens in this calcification process.

CONCLUSION

Calcification of the hydrophilic acrylic lenses is a relatively serious complication, but the conditions leading to its appearance and the physiopathology have not yet been fully elucidated. The surgeon should be very careful in the choice of the intraocular lens to implant, and even more so if the patient is diabetic.

Opacification of hydrophilic MemoryLens U940A intraocular lenses

PURPOSE

To determine the rate of opacification of hydrophilic MemoryLens U940A intraocular lenses (IOLs) (Mentor Ophthalmics, Inc.) in the given cohort and perform a histopathological and spectrophotometer analysis of 2 explanted opacified IOLs.

SETTING

Ophthalmology Department, Faculty Hospital, Nitra, Slovakia.

METHOD

This retrospective study comprised 182 patients (205 eyes) who had implantation of a MemoryLens U940A IOL from June 1997 to June 2000. The patients were examined using a slitlamp to detect the presence of IOL opacification. In 4 cases, the lenses were explanted because of significant opacification and patient-reported problems; 2 lenses were provided for further analysis. One unused reference MemoryLens U940A IOL was also evaluated. All IOL were stained with von Kossa to determine the presence of calcium in the opacification. To confirm the components presence of an ultraviolet (UV) absorber, the IOLs were examined with an Avatar 330 Fourier transfer infrared (IR) spectroscope and a UV visible spectrophotometer (Philips). The IR spectrums for the IOL were identified using an IR spectrum atlas. The opacified IOLs, reference IOL, and the IOL packaging were further examined to determine the presence of silicone.

RESULTS

Various amounts of opacification were found on the MemoryLens U940A IOL in 30 eyes (30 patients) (14.63%). Two explanted IOLs were positive for von Kossa staining, proving the presence of calcium deposits; the reference lens staining was negative. Spectrophotometry showed that the reference IOL and opacified IOLs were of the same polymer. The presence of the UV absorber on the benzophenone base was seen in the reference lens but not the opacified IOLs. In contrast, an increased concentration of low-molecular-weight components generated during the degradation of the polymer was present in the opacified lenses. The white cover pf the IOL is of polydimethyl siloxane, a silicone rubber. However, no silicone rubber was present in any examined lens, perhaps because the IOLs were in contact with alcohol during the histopathologic examination.

CONCLUSIONS

The results indicate opacification of the hydrophilic MemoryLens U940A was caused by premature consumption of the UV absorber in the polymer component of the IOLs optic, with a subsequent degradation of the polymer. Whether silicone from the white cover led to the IOL opacification, as reported with other types of hydrophilic IOLs, could not be confirmed.

Late postoperative opacification of MemoryLens hydrophilic acrylic intraocular lenses Case series and review

PURPOSE

To report clinical and spectrographic analyses of 2 explanted hydrophilic acrylic intraocular lenses (IOLs).

SETTING

John A. Moran Eye Center, Salt Lake City, Utah, USA, and Johannes Gutenberg-University, Department of Ophthalmology, Mainz, Germany.

METHODS

We report 6 cases of opacification of MemoryLens IOLs (Ciba Vision) that occurred approximately 2 years after implantation. The anterior and posterior surfaces of the IOLs had a white, frosted appearance, and the IOLs' interior looked brown, similar to the appearance of a brunescent cataract. Two of the IOLs were explanted because of a significant decrease in visual acuity. The IOLs were sent for further clinicopathologic analysis including scanning electron microscopy and energy dispersive x-ray spectroscopy (EDX).

RESULTS

Microscopic analysis revealed multiple, fine, granular deposits of various sizes on the surface of the lens optics. The EDX analysis showed the presence of calcium within the deposits.

CONCLUSIONS

Our cases show that hydrophilic acrylic IOLs can opacify even years after implantation. Analysis of the explanted IOLs revealed calcification.

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

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