Intraoperative explantation of two single-piece hydrophobic acrylic intraocular lenses due to surface deposits

Transient intraocular lens opacification during phacoemulsification surgery

Purpose

To report an interesting case of intraoperative opacification of intraocular lens (IOL).

Methods

This study is a report of a 61-year-old male patient who suffered from nuclear sclerosis cataract and had undergone phacoemulsification surgery. During surgery, intraoperative opacification of IOL (Cristal, Cristalens), which was a foldable, 13 mm, one piece, square edge and hydrophilic acrylic IOL, occurred. This phenomenon caused a surprise and a decision to explant the IOL, but the surgeon decided to keep the IOL in place. After a day, it was completely clear.

Results

The surgery was completed successfully without any complications, and the IOL was completely clear the day after surgery.

Conclusion

Acute, transient IOL opacification with unproven etiology may occur during cataract surgery.

Anterior surface opacification of intraocular lenses after Descemet's stripping automated endothelial keratoplasty

Descemet's stripping automated endothelial keratoplasty (DSAEK) is today recognised as the surgical procedure of choice for corneal endothelial dysfunction. The triple procedure (either staged or combined), whereby cataract surgery can be performed at the same time as endothelial keratoplasty, is well suited for patients with Fuch's endothelial dystrophy with decreased vision due to endothelial guttata, early stromal oedema and cataract formation. Recognised complications of DSAEK include donor graft detachment/dislocation, primary graft failure and pupillary block by air. Intraocular lens (IOL) opacification is a complication that is becoming apparent in patients who have undergone DSAEK and, to date, no definitive mechanism of such opacification has been discovered. Primary postoperative optic opacification of hydrophilic acrylic IOL designs has been attributed to the formation of calcium phosphate deposits. This has led to changes in lens designs, manufacturing processes and packaging. Secondary calcification is thought to be caused by environmental factors unrelated to the IOL model, such as breakdown of the blood-aqueous barrier. In this report, four cases of IOL anterior surface opacification are described in patients who required both cataract surgery and DSAEK. Only one case had cataract surgery and DSAEK performed concurrently, with the remainder having DSAEK performed at variable timeframes after cataract surgery.

Intraocular Lens Fragmentation Using Femtosecond Laser: An In Vitro Study

PURPOSE

To transect intraocular lenses (IOLs) using a femtosecond laser in cadaveric human eyes. To determine the optimal in vitro settings, to detect and characterize gasses or particles generated during this process.

METHODS

A femtosecond laser was used to transect hydrophobic and hydrophilic acrylic lenses. The settings required to enable easy separation of the lens fragment were determined. The gasses and particles generated were analysed using gas chromatography mass spectrometer (GC-MS) and total organic carbon analyzer (TOC), respectively.

RESULTS

In vitro the IOL fragments easily separated at the lowest commercially available energy setting of 1 μJ, 8-μm spot, and 2-μm line separation. No particles were detected in the 0.5- to 900-μm range. No significant gasses or other organic breakdown by products were detected at this setting. At much higher energy levels 12 μJ (4 × 6 μm spot and line separation) significant pyrolytic products were detected, which could be harmful to the eye. In cadaveric explanted IOL capsule complex the laser pulses could be applied through the capsule to the IOL and successfully fragment the IOL.

CONCLUSION

IOL transection is feasible with femtosecond lasers. Further in vivo animal studies are required to confirm safety.

TRANSLATIONAL RELEVANCE

In clinical practice there are a number of large intraocular lenses that can be difficult to explant. This in-vitro study examines the possibility of transecting the lasers quickly using femtosecond lasers. If in-vivo studies are successful, then this innovation could help ophthalmic surgeons in IOL explantation.

Morphologic Differences Observed by Scanning Electron Microscopy According to the Reason for Pseudophakic IOL Explantation

Purpose

To compare variations in surface morphology, as studied by scanning electron microscopy (SEM), of explanted intraocular lenses (IOLs) concerning the cause leading to the explantation surgery.

Methods

In this prospective multicenter study, explanted IOLs were analyzed by SEM and energy-dispersive X-ray spectroscopy. The IOLs were explanted in the centers of the research group from 2006 to 2012. The primary procedure was phacoemulsification in all cases.

Results

The study evaluated 40 IOLs. The main causes for explantation were IOL dislocation, refractive error, and IOL opacification. Those explanted due to dislocation demonstrated calcifications in 8 lenses (50%), salt precipitates in 6 cases (37.5%), and erythrocytes and fibrosis/fibroblasts in 2 cases (12.5%). In the refractive error cases, the SEM showed proteins in 5 cases (45.5%) and salt precipitates in 4 lenses (36.4%). In IOL opacification, the findings were calcifications in 2 of the 3 lenses (66.6%) and proteins in 2 lenses (66.6%).

Conclusions

A marked variation in surface changes was observed by SEM. Findings did not correlate with cause for explantation. Scanning electron microscopy is a useful tool that provides exclusive information regarding the IOL biotolerance and its interactions with surrounding tissues.

Calcification in hydrophilic intraocular lenses associated with injection of intraocular gas

PURPOSE

To report a distinct type of calcification in hydrophilic intraocular lenses in complicated, traumatized eyes with a history of intraocular gas use.

DESIGN

Observational case series.

METHODS

Three cases of hydrophilic intraocular lens (IOL) opacification confined to the pupillary area are reported from clinical practice in London, UK. Clinical details and analysis of the explanted intraocular lenses are provided with environmental scanning electron microscopy images and x-ray energy-dispersive spectroscopy results.

RESULTS

All cases were associated with use of intraocular gas in complicated traumatized eyes, and had central areas of IOL opacification over the pupillary zone, confined to the anterior surface of the IOL. Analysis of the lenses showed the opacified areas to be composed of calcium and phosphate.

CONCLUSION

The areas of opacification in all 3 hydrophilic IOLs were attributable to calcification. We postulate that intraocular gas use and the altered blood-aqueous barrier of these complicated traumatized eyes co-act to trigger secondary IOL calcification. Further experimental testing is needed to confirm this clinical association.

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.