Causes of intraocular lens opacification or discoloration

Abstract

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.

Effects of Intraocular Lens Opacification on Light Scatter, Stray Light, and Overall Optical Quality/Performance

“…2 Postoperative calcification represents the most important indication for explantation of hydrophilic acrylic IOLs. [2][3][4][5][6][7] Silicone lenses were also shown to calcify in eyes with asteroid hyalosis. [8][9][10] The condition named snowflake degeneration of rigid polymethylmethacrylate (PMMA) lenses still leads to explantation of a significant number of these IOLs, although it is usually observed in three-piece lenses manufactured in the 80s and early 90s.…”

“…11,12 Calcification and snowflake degeneration are leading causes of clinically significant IOL opacification. 3 Clinical studies on opacified IOLs demonstrated that they may be more associated with complaints of glare and ''foggy'' or ''cloudy'' vision, while visual acuity is not drastically reduced. 13,14 The quality of vision loss in affected patients appears to be predominantly related to increased forward light scattering and subsequently retinal stray light, which can give rise to a variety of subjective complaints, including glare in various illuminating conditions, halos around bright lights, color and contrast loss, as well as hazy vision.…”

Case-control study for clinical findings on intraocular lens opacity

“…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. Hydrophobic materials are specially opacified by excess influx of water, while hydrophilic IOLs are mostly affected by the formation of deposits/precipitates on the IOL surface or within the IOL substance 11,12,13 . Furthermore, 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 may be involved in the different designs of IOL opacification process.…”

“…11,17 Papers evaluating medical illness in association with IOL opacification suggest that a mechanism of bloodaqueous barrier impairment seemed to be associated with this postsurgical complication. 18 According to the literature, hydrophilic acrylic IOLs are likely to develop calcification when the concentrations of calcium, phosphate and albumin in the aqueous humor fluctuate due to blood-aqueousbarrier breakdown or other factors.…”

Confirmação do cálculo de lente intraocular através da refração intraoperatória

“…Problemas como deteriorização, opacificação e descoloração dos materiais das lentes têm sido relatados (1)(2)(3)(4)(5)(6)(7)(8) . Qualquer que seja a origem do comprometimento da lente intraocular, como manifestação clínica comum, ocorre perda progressiva da acuidade visual que pode resultar na extração e substituição por um novo implante intraocular.…”