Postoperative surface deposits on intraocular lenses in children

Analysis of opacification patterns in intraocular lenses (IOL)

Objective

Intraocular lens (IOL) opacification may cause severe visual impairment. The pathogenesis remains unclear. The aim of this study was to analyse opacification patterns in different IOLs. Therefore, this multicentre, retrospective, observational study was conducted at Ludwig-Maximilians-University, Munich, Germany and University-Hospital Basel, Switzerland.

Methods and analysis

In this study, 75 opacified IOLs were identified and classified after extraction. Macroscopical photo documentation, light and electron microscopic analysis were done.

Results

68 acrylic-hydrophilic single-piece-IOLs, 1 acrylic-hydrophilic 3-piece-IOL, 6 acrylic-hydrophobic 3-piece-IOLs were extracted. The dataset comprised IOLs known for opacification and IOLs not having been reported yet. 67 IOLs showed a fine-granular and 8 IOLs a crust-like opacification pattern. According to literature, 62 of the fine-granular opacified IOLs were graded into type 1 (processing/packaging-induced primary opacification) and 13 into type 2 (secondary opacification of unknown aetiology). The anterior surface of the IOLs was affected in all 75 IOLs, the posterior surface only in 23 cases. Of all 67 fine-granular IOLs, 43 had a central defect and 21 had a zone without opacification (clear islet).

Conclusion

In our series, the morphology of IOL opacification did not follow the existing pathogenetic classification that strictly discriminates between primary and secondary causes. Fine-granular IOL opacification occurs with similar patterns in both type 1 and type 2 IOL opacification, while a crust-like pattern was only detected in type 2 IOL opacifications. Consequently, susceptibility of an IOL to opacification is caused by a multifactorial combination of material and processing properties as well as individual (pathological) conditions of the patient.

A review of late intraocular lens opacifications

PURPOSE OF REVIEW

Phacoemulsification cataract surgery is one of the most commonly performed surgical procedure worldwide. In the majority of cases, intraocular lenses (IOLs) are implanted. Due to the increasing life expectancy and the fact that cataract surgery is performed in earlier stages, the anticipated IOL duration in the eye has increased over the last decades. The aim of this study was to review the types and describe the characteristics of late intraocular lens opacifications.

RECENT FINDINGS

Calcification was the most commonly reported type of opacification in hydrophilic IOLs; it usually negatively impacted the visual function and required IOL explantation. Glistening manifested in hydrophobic acrylic lenses and was frequent in some IOL models. In most cases glistening and subsurface nanoglistenigs do not lead to a decline in visual acuity or require IOL exchange. Current studies indicate that fluid-related phenomena may induce straylight, leading to a decrease of comfort and quality of vision.

SUMMARY

Several reports on late IOL opacifications have been published in recent years. In some cases, particularly in glistening, the development of the opacifications might be related to IOL aging. The influence of the fluid-related microvacuoles on the quality of vision requires further research.

Calcification of a Rayner Centerflex 570H hydrophilic Acrylic Intraocular Lens following Vitrectomy for Retinal Detachment: A Clinicopathologic Report

Purpose

The case of a 71-year-old man who complained of progressive, unilateral visual blurring following vitrectomy for retinal detachment due to opacification of his Rayner Centerflex 570H intraocular lens (IOL) implant is reported. Intraocular lens exchange was carried out and the explanted lens analyzed. The same model lens in his fellow eye has remained clear.

Methods

Clinicopathologic case report.

Results

Scanning electron microscopy and energy-dispersive x-ray analysis confirmed the presence of hydroxyapatite deposits within the anterior surface of the IOL.

Conclusions

To our knowledge, this is the first clinicopathologic case report of calcification of this model IOL in an adult patient. The sequence of events, unilaterality and pathologic findings suggest secondary calcification, which could have been related to severe postoperative inflammation and associated blood-aqueous barrier breakdown.

Capsular Outcomes After Pediatric Cataract Surgery Without Intraocular Lens Implantation: Qualitative Classification and Quantitative Measurement

The objective of this study was to investigate capsular outcomes 12 months after pediatric cataract surgery without intraocular lens implantation via qualitative classification and quantitative measurement.This study is a cross-sectional study that was approved by the institutional review board of Zhongshan Ophthalmic Center of Sun Yat-sen University in Guangzhou, China.Digital coaxial retro-illumination photographs of 329 aphakic pediatric eyes were obtained 12 months after pediatric cataract surgery without intraocular lens implantation. Capsule digital coaxial retro-illumination photographs were divided as follows: anterior capsule opening area (ACOA), posterior capsule opening area (PCOA), and posterior capsule opening opacity (PCOO). Capsular outcomes were qualitatively classified into 3 types based on the PCOO: Type I-capsule with mild opacification but no invasion into the capsule opening; Type II-capsule with moderate opacification accompanied by contraction of the ACOA and invasion to the occluding part of the PCOA; and Type III-capsule with severe opacification accompanied by total occlusion of the PCOA. Software was developed to quantitatively measure the ACOA, PCOA, and PCOO using standardized DCRPs. The relationships between the accurate intraoperative anterior and posterior capsulorhexis sizes and the qualitative capsular types were statistically analyzed.The DCRPs of 315 aphakic eyes (95.8%) of 191 children were included. Capsular outcomes were classified into 3 types: Type I-120 eyes (38.1%); Type II-157 eyes (49.8%); Type III-38 eyes (12.1%). The scores of the capsular outcomes were negatively correlated with intraoperative anterior capsulorhexis size (R = -0.572, P < 0.001), but no significant correlation with intraoperative posterior capsulorhexis size (R = -0.16, P = 0.122) was observed. The ACOA significantly decreased from Type I to Type II to Type III, the PCOA increased in size from Type I to Type II, and the PCOO increased from Type II to Type III (all P < 0.05).Capsular outcomes after pediatric cataract surgery can be qualitatively classified and quantitatively measured by acquisition, division, definition, and user-friendly software analyses of high-quality digital coaxial retro-illumination photographs.

[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.

Capsular Outcomes Differ with Capsulorhexis Sizes after Pediatric Cataract Surgery: A Randomized Controlled Trial

Capsular outcomes of anterior/posterior capsulorhexis opening (ACO/PCO) are essential for performing a secondary in-the-bag intraocular lens implantation. To compare the capsular outcomes with different primary capsulorhexis sizes, Thirty-eight eligible patients (45 eyes) were randomly assigned to three groups by anterior capsulorhexis diameter (Group A: 3.0-3.9, Group B: 4.0-5.0, and Group C: 5.1-6.0 mm). The areas of ACO/PCO and posterior capsule opening opacity (PCOO) as primary outcomes, while, the incidence of visual axis opacity (VAO) as secondary outcome were measured at follow-up visits. Among the thirty eyes included in the final analysis, the mean area of the ACO decreased significantly, whereas the PCO enlarged with time. Group A had the highest anterior capsule constriction and percentage reduction, which increased with time. There were significant differences in the percentage reductions at 6 months and 1 year compared to 1 month in Group A and B. Group C had the highest posterior capsule enlargement. The percentage of PCOO to PCO area and the incidence of VAO was highest in Group A and lowest in Group C. Thus, Capsulorhexis diameter of 4.0-5.0 mm may yield better capsular outcomes, considering moderate contraction of ACO, moderate enlargement of PCO, and lower percentage of PCOO and VAO.

Opacification of intraocular lenses implanted during infancy: a clinicopathologic study of 4 explanted intraocular lenses

OBJECTIVE

To report the clinicopathologic features of 4 opacified, single-piece, hydrophilic, acrylic intraocular lenses (IOLs) explanted from children who had undergone IOL implantation during infancy.

DESIGN

Observational case series.

PARTICIPANTS

Four IOLs explanted from 4 eyes of 3 children for visually significant opacification were included in the study.

METHODS

The clinical details of each case were obtained to look for possible risk factors for IOL opacification. The explanted IOLs were subjected to gross examination, staining by alizarin red 1% for calcium, scanning electron microscopy, and energy-dispersive x-ray spectroscopy (EDS). Levels of calcium and phosphorous were analyzed in the serum of all cases and in the aqueous humor of 1 case.

MAIN OUTCOME MEASURES

Morphologic features and composition of deposits.

RESULTS

Two cases had congenital cataract while one case was after bilateral lens sparing vitrectomy for retinopathy of prematurity. All underwent surgery during infancy with implantation of an IOL. The IOLs were explanted 8 months after surgery from 4 eyes of 3 children at the age of 17, 25, and 26. All the children received a single-piece hydrophilic acrylic IOL. The IOLs were in situ for an average duration of 13.86 months. The deposits were in the shape of a bicycle wheel on 3 IOLs and looked like fish eggs on 1 IOL. All deposits stained bright orange with alizarin red. On EDS, the deposits were found to be composed of calcium, phosphate, and silicone.

CONCLUSIONS

The morphologic features and composition of IOL deposits in 2 cases were similar to those of earlier reports in adults. The hydrophilic nature of the IOL material, sulcus implantation, and postoperative inflammation may be possible risk factors for opacification.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Spectroscopic study of explanted opacified hydrophilic acrylic intraocular lenses

PURPOSE

To report a detailed spectroscopic analysis of explanted hydrophilic acrylic intraocular lenses (IOLs) that were removed because of postoperative opacification of the lens optic.

METHODS

Thirteen Hydroview H60M (Bausch & Lomb Surgical) IOLs were explanted from 13 different patients on average 56 months after phacoemulsification and IOL implantation. All patients had decreased visual acuity because of a fine granularity of the optical surface of the IOLs. The surface was investigated by gross, microscopic, histochemical and scanning electron microscopic analysis, and the elemental composition of the opacified IOLs was determined by X-ray fluorescence spectroscopy (XRF). The spectrograms were compared to three different originally packed and never-implanted hydrophilic acrylic IOLs.

RESULTS

Light and scanning electron microscopy of the optical surface of explanted IOLs revealed multiple fine granular deposits varying in size and shape that were positive for alizarin red. XRF confirmed that the explanted IOLs contained not only the previously reported calcium and phosphorous (calcium apatite), chlorine, silicone, sodium, aluminum and magnesium but also iron, sulfur, potassium as well as lesser amounts of iodine, zinc, strontium and yttrium.

CONCLUSION

This is the first spectroscopic analysis determining the content of more than 10 elements of explanted and originally packed never-implanted hydrophilic acrylic IOLs. The possible origin of the different elements obtained from the spectrograms and their implications are discussed.

Surface calcification of hydrophilic acrylic intraocular lens related to inflammatory membrane formation after combined vitrectomy and cataract surgery

Two patients complained of blurred vision approximately 6 months after having combined vitrectomy and phacoemulsification with implantation of a C-flex 570C hydrophilic acrylic intraocular lens (IOL). Multiple granules were noted on the anterior surface of the IOLs in both patients. Intraocular lens exchange was performed in both eyes, and the explanted IOLs were sent for histopathological analysis. Scanning electron microscopy confirmed the presence of cracks and granules on the IOL surfaces and energy-dispersive x-ray spectroscopy demonstrated calcium deposition. Based on the calcification pattern on the anterior surface of the IOLs, 2 additional cases of opacification were identified under slitlamp examination.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Clinicopathological correlation of 3 patterns of calcification in a hydrophilic acrylic intraocular lens

We present 3 cases of opacification in the Biocomfold 92S intraocular lens (IOL), with a documented increase in the opacification over time in 1 case. Histopathological analysis revealed the opacification was caused by calcification in the IOL's optic material. The pattern of calcium deposition, however, was different in each IOL. The causative mechanisms for this complication are unclear. Further research is warranted.

Calcification of Hydroview H60M intraocular lenses: aqueous humor analysis and comparisons with other intraocular lens materials

PURPOSE

To compare the level of calcification on Hydroview H60M hydrophilic acrylic intraocular lenses (IOLs) (Bausch & Lomb) and other IOL materials.

SETTING

Omori Medical Center, Department of Ophthalmology, Toho University, Tokyo, Japan.

METHODS

The levels of calcification on Hydroview H60M hydrophilic acrylic IOLs, AcrySof SA60AT hydrophobic acrylic IOLs (Alcon Surgical, Inc.), Sensar AR40e hydrophobic acrylic IOLs (Advanced Medical Optics), ClariFlex (Advanced Medical Optics) silicone IOLs, and the MeniFlex ENV13 (Menicon) poly(methyl methacrylate) IOLs were compared in a calcium phosphate solution containing albumin. In a concentration-change experiment, the calcium and phosphate concentration levels were changed and the results observed by scanning electron microscopy.

RESULTS

The Hydroview H60M IOL had the largest amount of deposits. Small amounts of deposits were found on the other IOLs in the following decreasing order: AcrySof SA60AT, Sensar AR40e, ClariFlex, and MeniFlex ENV13. The amount of deposits on the Hydroview H60M IOLs was statistically significantly greater than the amount on the other IOLs (P<.01).

CONCLUSIONS

The hydrophilic acrylic IOLs (Hydroview H60M) had significantly higher amounts of calcified deposits than IOLs of other materials, indicating that hydrophilic acrylic IOLs easily accumulate calcified deposits in the body when the concentrations of calcium, phosphate, and albumin in the aqueous humor fluctuate as a result of a blood-aqueous barrier breakdown.

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.

Causes of intraocular lens opacification or discoloration

Various pathologic processes may lead to clinically significant opacification or discoloration of the optic component of intraocular lenses (IOLs) manufactured from different biomaterials and in different designs. Factors such as the patient's associated conditions, the manufacturing process, the method of IOL storage, the surgical technique and adjuvants, or a combination of these may be involved. The complication may be observed intraoperatively or postoperatively from a few hours after implantation to many years after surgery, depending on the processes involved. Based on a review of the literature as well as our own laboratory analyses, the following types of processes were identified: formation of deposits/precipitates on the IOL surface or within the IOL substance; opacification by excess influx of water in hydrophobic materials; direct discoloration by capsular dyes or medications; coating by substances such as ophthalmic ointment and silicone oil; and a slow, progressive degradation of the IOL biomaterial.