Evaluation of calcification of a hydrogel intraocular lens by optical coherence tomography

Delayed surface opacification of a hydroview intraocular lens

The insertion of an intraocular lens during cataract surgery is routine but delayed opacification of hydrophilic foldable intraocular lenses (IOLs) has been increasingly noticed as a late post-operative complication. Such opacification may present with reduced visual acuity and can be diagnosed with slitlamp biomicroscopy. Lens explantation may be required. We report an 89-year-old female presenting with opacification of a Hydroview IOL and correlate the clinical findings of the lens in situ with the light microscopy of the explanted lens, as well as transmission electron microscopy (TEM), scanning electron microscopy (SEM) and elemental analysis. Pathological analysis of an explanted IOL may assist in a better understanding of the condition and may become relevant in medico-legal proceedings.

Optic shrinkage and retraction in opacified hydrophilic acrylic intraocular lens: an anterior segment optical CT-based observation

Intraocular lens (IOL) opacification is a rare phenomenon noted with hydrophilic acrylic IOLs. We report a case of advanced IOL opacification appreciated on anterior segment optical CT (ASOCT)as a shrunken biconcave optic retracted away from the posterior capsule (PC), unlike the other eye which had a clear biconvex IOL of similar material abutting the PC. After IOL exchange, the affected eye was noted to have more folds and Elschnig's pearls on the PC when compared with the other eye. Our case points towards rare IOL changes seen in advanced cases of opacification, their association with posterior capsular changes and the aid of ASOCT as a non-invasive tool in diagnosing them correctly.

Anterior segment optical coherence tomography of intraocular lens opacification

Postoperative opacification of a hydrophilic acrylic intraocular lens (IOL) is an uncommon complication. A 57-year-old diabetic female who had undergone phacoemulsification with IOL implantation in her right eye 16 years back presented with diminution of vision in the same eye for 3 years. Significant IOL opacification was observed clinically and anterior segment optical coherence tomography clearly delineated the intraoptic deposits, sparing the haptics, and edges of the optic. IOL explant and exchange was performed leading to restoration of visual acuity to 6/9. Histochemical evaluation of the IOL confirmed that the hydrophilic acrylic IOL optic had calcium deposits.

Intraluminal Deposits Found in Glaucoma Tube Shunts Via Anterior Segment Ocular Coherence Tomography

PURPOSE

To describe and characterize a novel observation of intraluminal deposits of glaucoma tube shunts (TS) using spectral domain (SD) ocular coherence topography (OCT).

PATIENTS AND METHODS

Fifteen TS in 11 patients diagnosed with primary open-angle, neovascular, aphakic, and uveitic glaucomas. Both Ahmed (n=11) and Baerveldt (n=4) TS were examined with 5-line raster anterior segment SD-OCT imaging.

RESULTS

The exposed tubes of 2 patients had highly reflective intraluminal deposits in the corresponding exposed areas. Seven tubes without exposure had a thin rim of highly reflective material. Six tubes were clear of luminal deposits. The most common diagnosis in the study was uveitic glaucoma which occurred in 5 of the 15 eyes (33%). The next most common diagnosis was primary open-angle glaucoma which occurred in 4 of the 15 eyes (25%). There were 2 nonvalved Baerveldt tubes in each group. The mean duration of TS implantation was 15.0 months in the deposit group and 33.7 months in the group without luminal deposits. The majority of patients in each group were using eye drops at presentation (88.9% deposit, 83.3% clear), and the average intraocular pressure was 20.2 mm Hg in the deposit group and 19.0 mm Hg in the clear group.

CONCLUSIONS

Anterior segment OCT imaging may be used to evaluate TS integrity. Intraluminal deposits in TS may occur as a natural response to implanted drainage device, possibly as an inflammatory response.

Opacification of hydrophilic acrylic intraocular lens attributable to calcification: investigation on mechanism

PURPOSE

To identify the nature and to investigate the biochemical mechanisms leading to late opacification of implanted hydrophilic acrylic intraocular lenses (IOLs).

DESIGN

Retrospective laboratory investigation.

METHODS

setting: Department of Ophthalmology, Medical School, Department of Chemical Engineering, Laboratory of Inorganic and Analytical Chemistry, University of Patras and FORTH-ICEHT, Greece. study population: Thirty IOLs were explanted one to 12 years postimplantation attributable to gradual opacification of the lens material. observation procedures: Materials analysis was done using scanning electron microscopy (SEM) equipped with a microanalysis probe (EDS), confocal microscopy, x-ray diffraction (XRD), and Fourier transform infrared (FTIR) for the identification of the substances involved in the opacified lenses.

RESULTS

SEM investigation showed plate-like as well as prismatic nanoparticle deposits of calcium phosphate crystallites on the surface and in the interior of opacified IOLs. The plate-like deposits exhibited morphology and particle size typical for octacalcium phosphate (OCP), while the respective characteristics of the prismatic nanocrystals were typical of hydroxyapatite (HAP). EDS analysis confirmed the chemical composition of the deposits. Aqueous humor analysis showed that the humor is supersaturated with respect to both OCP and HAP, favoring the formation of the thermodynamically more stable HAP, while the formation and kinetic stabilization of other transient phases is also very likely. In vitro experiments using polyacrylic materials confirmed the clinical findings.

CONCLUSIONS

Hydrophilic acrylic IOLs' opacification may be attributed to the deposition of calcium phosphate crystallites. HAP is the predominant crystalline phase of these crystallites. Surface hydroxyl groups of the polyacrylic materials facilitate surface nucleation and growth.

In vivo imaging of posterior capsule opacification using Spectral Optical Coherence Tomography

Three years after uneventful extracapsular cataract extraction with implantation of a poly(methyl methacrylate) (PMMA) intraocular lens (IOL) (MZ60BD, Alcon) in a 74-year-old man, the anterior segment of the right eye was photographed with a Canon EOS 300D digital camera and examined with a slitlamp and a prototype spectral optical coherence tomography (SOCT) instrument. Subsequently, a neodymium:YAG laser posterior capsulotomy was performed, followed by another examination. The quality of the SOCT images was adequate for detailed cross-sectional evaluation of the IOL, posterior capsule opacification (PCO), and morphological changes after laser capsulotomy. En face contour maps of PCO distribution were created from 3-dimensional SOCT data. The results presented indicate future applicability of SOCT technology in evaluating modern IOL designs and investigating the process of PCO formation.