Currently, intraocular lens (IOL) opacification is a rare but a well-known late-term complication of cataract surgery.1–12 Although several studies have shown late opacifications of polymethylmethacrylate,1,2 silicone,3,4 hydrophilic acrylic,5–19 and hydrophilic acrylic coated with hydrophobic surface IOL designs,20,21 visually significant opacification leading to IOL explantation is commonly reported in cases with hydrophilic acrylic IOLs.12–20
Recently published case reports have demonstrated opacified hydrophilic acrylic IOLs after ocular surgeries such as corneal transplantation procedures involving multiple injections of intracameral gas or vitreoretinal interventions combined with intravitreal SF6 or C3F8 gas injections.6–10,14–16 Gross and histochemical analysis of explanted hydrophilic acrylic IOLs revealed that calcium phosphate crystalline deposits on or within the optic material are the main reason of opacification.20–23 Because various factors may be the cause of such calcification, which has been attributed to IOL material itself, presence of phosphate components in the ophthalmic viscosurgical devices (OVDs) or calcium in the irrigating solutions used during phacoemulsification surgery, as well as the supersaturated content of aqueous humor, the exact mechanism is still unknown.22–25 However, opacification following silicone oil (SO) injection is a less well-known phenomenon.18,19 Herein, we report a case series of 32 eyes with IOL opacification following vitrectomy and SO injection.
Patients and Methods
Thirty-two eyes of 31 patients with the diagnosis of IOL opacification between September 2010 and May 2019 were evaluated retrospectively. All patients had been referred to Dokuz Eylul University, Department of Ophthalmology, with the diagnosis of rhegmatogenous retinal detachment and had a history of previous phacoemulsification with hydrophilic acrylic IOL implantation. In all eyes, due to the presence of large, multiple and/or inferior tears with or without proliferative vitreoretinopathy (PVR) immediate 23- or 25-gauge pars plana vitrectomy (PPV) was performed using 1,300 centistoke (cs) SO endotamponade (Oxane; Bausch + Lomb, Rochester, NY). Silicone oil removal (SOR) was performed with two-port 23- or 25-gauge vitrectomy, where SO was exchanged with balanced salt solution (BSS; Alcon Laboratories, Fort Worth, TX).
Demographics as well as the data about the ophthalmologic examinations, including best-corrected visual acuity (BCVA), intraocular pressure, slit-lamp and retina evaluation including B-scan ultrasonography scans of all study participants, were recorded. Details about their previous cataract surgeries were collected from their previous medical records. The diagnosis of IOL opacification was based on slit-lamp biomicroscopy. All opacified IOLs were exchanged by the same surgeon (AY) after a written informed consent was provided and signed by the patient. This study was performed in accordance with the ethics standards of the institutional review board and with the Helsinki declaration.
In IOL exchange surgery, following topical anesthesia, the anterior chamber (AC) and the capsular bag were filled with a cohesive OVD (Healon GV; Advanced Medical Optics, Santa Ana, CA), and the anterior capsule was carefully separated from the opacified IOL surface. Subsequently, the IOL was subluxated into the AC, where it was either folded with microforceps or divided into two halves with scissors and removed through a clear 3.5-mm corneal incision. A three-piece hydrophobic acrylic IOL (Acrysof MA60AC; Alcon, Fort Worth, TX) was then implanted into the capsular bag or ciliary sulcus according to the presence of both posterior capsular and zonular integrity. In two cases with significant zonular weakness, 13-mm Morcher Cionni-modified capsular tension rings type 2L were inserted into the capsular bag and fixated to the sclera at 3-o'clock and 9-o'clock quadrants using 9-0 polypropylene looped-sutures with a long curved needle (PC-9; Alcon Surgical, Fort Worth, TX).
The explanted IOLs were kept in dry state and sent to the Intermountain Ocular Research Center (John A. Moran Eye Center, University of Utah) for further analysis, where unstained specimens were evaluated and photographed under a light microscope (Olympus Optical Co., Ltd., Tokyo, Japan). The specimens were rinsed individually in distilled water, and immersed into 1% alizarin red solution, which is a special stain for calcium, for 20 minutes. They were also rinsed again in distilled water before the reexamination under the light microscope.
The data were stored on a computerized database and analyzed using SPSS version 22.0 statistical software (IBM, Armonk, NY). After normality was tested with Shapiro-Wilk test, paired samples t-test was used for the statistical analysis of the visual acuity alteration in eyes underwent IOL exchange surgery, and a P value of less than .05 was considered as significant.
The mean age of the patients was 57.0 ± 13.5 years (range: 26–79 years) in the initial diagnosis of IOL opacification; 12 (38.7%) were female and 19 (61.3%) were male. They had no concomitant systemic disease except for hypertension in three cases (9.7%). Five eyes (15.6%) had a previous history of high myopia (≥ 7.0 diopters), which was the only ocular abnormality in the entire study population. All cases had undergone phacoemulsification with hydrophilic acrylic IOL implantation between October 2003 and September 2014. Sixteen eyes (50%) had a posterior capsular defect due to posterior capsular rupture during surgery in nine eyes (28.1%) and postoperative YAG capsulotomy in seven eyes (21.9%).
The mean period between phacoemulsification and retinal detachment was 23.9 ± 21.2 months (range: 1–93 months) (Table 1). In detailed slit-lamp examination, prior to detachment surgery there was no evidence of opacification and the mean preoperative BCVA was 20/400 (range: 20/2000-20/40). During the follow-up after vitrectomy, three eyes (9.4%) underwent reoperation with inferior retinectomy and SO exchange due to advanced inferior PVR under SO. Including those reoperated eyes, the mean duration of SO endotamponade was 4.6 ± 2.0 months (range: 3–7 months).
Demographics and Ophthalmologic Findings (32 Eyes of 31 Cases)
With the exception of two eyes, all IOL opacification was detected during the follow-up period following SOR (Figure 1). In those two eyes, opacification was detected under SO 14 weeks and 18 weeks after the first surgery. They had both required reoperation with inferior retinectomy and SO exchange. One of them was a hydrophilic acrylic IOL coated with hydrophobic surface. Mean interval between SOR and IOL opacification was 22.0 ± 18.6 months (range: 3–88 months). Surgery for IOL exchange was performed in 12 eyes (37.5%) having significant visual impairment. Among them, the mean BCVA was 20/50 (range: 20/200–20/32) just after SOR whereas 20/700 (range: 20/2000–20/200) following opacification; and became 20/63 (range: 20/400–20/25) after the IOL exchange surgery (P = .096 and P = .001, respectively). Demographics and clinical features of the study population were shown in Table 1. In eyes that IOL exchange was not required, during the long-term follow-up (mean: 47.3 ± 22.1 months), IOL opacification remained stable in size and location.
Opacified intraocular lens (IOL) was diagnosed on slit-lamp biomicroscopy. Bulky deposits could be easily seen (A); however, more fine and diffuse deposits located on the surface of the IOL optic required more elaborate examinations with slit-lamp (B).
Gross evaluation of the explanted IOLs revealed an obvious whitish color change on the optic surface with relatively clear haptics. Light microscopy showed the presence of multiple fine granular deposits covering the optical surfaces of the opacified IOLs in a circular pattern located within the area of haze or such whitish discoloration. Although fine granules were present on both optical surfaces, they were more prominent on the anterior optic surface of the explanted IOLs. The haptics were found to be free of such deposits in all evaluated specimens. Histochemical analysis with alizarin red revealed significant calcification mostly on the surface of all lens optics; however, two had pigmentary dispersion on the surface of the loops (Figure 2).
Light microscopy of the explanted intraocular lenses revealed severe calcification (A–F). Calcified deposits could be seen mostly on the surface/subsurface of the lens optics. Such light photomicrographs exhibit pigmentary dispersion, which could be seen on the surface of the loops, and other deposits including surface contaminants such as fibers, dust-like deposits, as well as crystals probably corresponding to dried viscoelastic or balanced salt solutions used in the explantation surgery (A–F).
IOL opacification is rare also but one of the most annoying late-term complications of cataract surgery and commonly leads to explantation of opacified IOL due to visual impairment.9–28 Although several authors have published about late opacification with different IOL materials and designs, it has been frequently reported in hydrophilic acrylic IOLs in the literature.1–21 Calcification is proven as the major cause of opacification in hydrophilic acrylic IOLs.13–17,20–23 According to the literature opacification may be a primary calcification that is related with the IOL itself or the metabolic changes in the aqueous humor secondary to breakdown in blood-aqueous barrier (BAB) may trigger the calcification process.20–23 However, any patient related factors have not been proven yet; concomitant systemic conditions such as diabetes, chronic kidney disease, gout, and hyperparathyroidism, as well as ocular disorders including diabetic retinopathy, pseudoexfoliation, glaucoma, uveitis, asteroid hyalosis, or excessive postoperative inflammation, are speculated to trigger such calcification process by predisposing to produce crystalline deposits within aqueous humor, or increase the inflammation that facilities BAB breakdown.2,11–17,20–24
From the perspective of IOL opacification, the interaction of hydrophilic IOLs with SO is not well documented. Lee et al.29 reported a case of calcium deposits on the surface of an explanted C-flex 570C hydrophilic lens (Rayner Global, Worthin, United Kingdom), which developed 6 months after SOR in a 24-year-old myopic female who had oil in the eye for 3 months after retinal detachment repair. Close observation under slit-lamp examination revealed well-demarcated uniform focal granular protrusions, which differed from inflammatory debris or iris pigments on the IOL surface. They claimed that such opacification is not attributable to primary calcification caused by the IOL material or the manufacturing or packaging process, but rather to a secondary calcification process induced by environmental factors.
Gregori et al.18 reported Akreos hydrophilic acrylic IOL (Akreos AO60; Bausch + Lomb, Rochester, NY) opacification under SO 5 months postoperatively. They mentioned that opacity did not enlarge after SOR and remained stable in appearance. Rubin and Baker19 reported another case of Akreos opacification associated with 5,000 cs SO (Bausch + Lomb, Rochester, NY) tamponade. During the planned SOR, attempts to scrub the surfaces of the Akreos IOL were not successful.
It is always hard to determine the exact onset of opacification, since visual deterioration may not be significant at the beginning in many cases. However, literature reveals that cases required IOL explantation during their second or third year after the implantation.12,20,22,30 The mean interval between phacoemusification surgery and IOL opacification was 27.4 ± 18.3 months, and the history of SO endotamponade was the common finding in our study population. We also had two eyes with IOL opacification under SO endotamponade. Prolonged exposure to SO may have an additional impact on opacification in susceptible IOLs by facilitating the precipitation of calcium on the surface of IOL.
Localized anterior optical surface calcification was reported according to vitreous tamponade with gas or SO in the literature, and migration of such endotamponade agents into anterior chamber (AC) through zonular fiber defects was attributed as the possible cause in cases underwent vitrectomy surgery.9,10,25,29 Nevertheless, there had been a lack of data about SO migration into the AC via ruptured posterior capsule or zonular defects in such cases. Any accumulation of emulsified SO droplets were not demonstrated in the AC of any study patients.
In a study of the structural characteristics of hydrophilic acrylic IOLs, Gartaganis et al.31 suggested that the surface hydroxyl groups on the polyacrylic materials facilitate precipitation of hydroxyapatite. Such precipitation occurs even more significantly when the aqueous humor is supersaturated with calcium. Although the presence of an intact posterior lens capsule and the lack of direct physical contact of the SO bubble with the IOL surface during surgery or afterward in their two cases with opacified IOL after PPV and SO injection, Gartaganis et al.21 accused the increased intraocular inflammation related to combined surgery for the opacification. Despite a lack of prolonged intraocular inflammation, a short-term disruption of the BAB was thought to be a leading cause for increased intraocular calcium concentration and related IOL opacification in their cases. In our study, all eyes had a history of SO endotamponade and opacifications were similarly located on the anterior side of the explanted IOLs. We hypothesized that surgery increases both inflammation and calcium concentration in the AC and SO may have an additional impact on the AC calcium to reach peak levels so that it gradually accumulates on the anterior side of the IOL. This process continues slowly even after SOR until all calcium crystals in AC precipitates on IOL surface and then opacification remains stable.
Posterior capsular defect was present in 50% of our entire study group. Although it was present in five out of 12 eyes that underwent IOL explantation surgery (41.7%), having such defect did not reveal any additional abnormalities on both gross macroscopic and light microscopic findings when compared to the remaining seven eyes with intact posterior capsule. Hence, it is thought that presence of a posterior capsular defect does not have a major impact on IOL opacification.
To the best of our knowledge, this is the first report of a relatively large case series in hydrophilic acrylic IOL opacification after vitreoretinal surgery with SO tamponade. Vitreoretinal surgeons should be aware of that some hydrophilic IOLs may have the potential of opacification following SO endotamponade and need to be followed-up for longer periods even after SOR.
- Apple DJ, Peng Q, Arthur SN, et al. Snowflake degeneration of polymethyl methacrylate posterior chamber intraocular lens optic material: a newly described clinical condition caused by unexpected late opacification of polymethyl methacrylate. Ophthalmology. 2002;109(9):1666–1675. doi:10.1016/S0161-6420(02)01122-3 [CrossRef] PMID:12208715
- Driver TH, Li HJ, Sharma A, et al. Late-onset, snowstorm-like appearance of calcium deposits coating a poly(methyl methacrylate) posterior chamber intraocular lens. J Cataract Refract Surg. 2016;42(6):931–935. doi:10.1016/j.jcrs.2016.06.003 [CrossRef] PMID:27373401
- Werner L, Dornelles F, Hilgert CR, et al. Early opacification of silicone intraocular lenses: laboratory analyses of 6 explants. J Cataract Refract Surg. 2006;32(3):499–509. doi:10.1016/j.jcrs.2005.12.137 [CrossRef] PMID:16631065
- Stringham J, Werner L, Monson B, Theodosis R, Mamalis N. Calcification of different designs of silicone intraocular lenses in eyes with asteroid hyalosis. Ophthalmology. 2010;117(8):1486–1492. doi:10.1016/j.ophtha.2009.12.032 [CrossRef] PMID:20537395
- Mojzis P, Studeny P, Werner L, Piñero DP. Late opacification of a hydrophilic acrylic intraocular lens in Europe. Eur J Ophthalmol. 2016;26(2):e24–e26. doi:10.5301/ejo.5000704 [CrossRef] PMID:26541107
- Werner L, Wilbanks G, Nieuwendaal CP, et al. Localized opacification of hydrophilic acrylic intraocular lenses after procedures using intracameral injection of air or gas. J Cataract Refract Surg. 2015;41(1):199–207. doi:10.1016/j.jcrs.2014.10.025 [CrossRef] PMID:25465216
- Neuhann IM, Neuhann TF, Rohrbach JM. Intraocular lens calcification after keratoplasty. Cornea. 2013;32(4):e6–e10. doi:10.1097/ICO.0b013e31826150de [CrossRef] PMID:23010776
- Khurana RN, Werner L. Calcification of a hydrophilic acrylic intraocular lens after pars plana vitrectomy. Retin Cases Brief Rep. 2018;12(3):204–206. doi:10.1097/ICB.0000000000000472 [CrossRef] PMID:27787410
- Walker NJ, Saldanha MJ, Sharp JA, et al. Calcification of hydrophilic acrylic intraocular lenses in combined phacovitrectomy surgery. J Cataract Refract Surg. 2010;36(8):1427–1431. doi:10.1016/j.jcrs.2010.04.011 [CrossRef] PMID:20656168
- Dhital A, Spalton DJ, Goyal S, Werner L. Calcification in hydrophilic intraocular lenses associated with injection of intraocular gas. Am J Ophthalmol. 2012;153(6):1154–60.e1. doi:10.1016/j.ajo.2011.11.017 [CrossRef] PMID:22325304
- Jorge PA, Jorge D, Ventura CV, et al. Late opacification in hydrophilic acrylic intraocular lenses: analysis of 87 eyes in a random sample of 102 patients. J Cataract Refract Surg. 2013;39(3):403–407. doi:10.1016/j.jcrs.2012.09.023 [CrossRef] PMID:23317778
- Neuhann IM, Werner L, Izak AM, et al. Late postoperative opacification of a hydrophilic acrylic (hydrogel) intraocular lens: a clinicopathological analysis of 106 explants. Ophthalmology. 2004;111(11):2094–2101. doi:10.1016/j.ophtha.2004.06.032 [CrossRef] PMID:15522377
- Abdul-Rahman A, House P, Richards J. Intraocular lens dystrophic calcification after trans-scleral diode laser treatment for a cyclodialysis cleft. Am J Ophthalmol Case Rep. 2018;11:78–83. doi:10.1016/j.ajoc.2018.06.012 [CrossRef] PMID:30014050
- Yildirim TM, Auffarth GU, Łabuz G, Bopp S, Son HS, Khoramnia R. Material analysis and optical quality assessment of opacified hydrophilic acrylic intraocular lenses after pars plana vitrectomy. Am J Ophthalmol. 2018;193:10–19. doi:10.1016/j.ajo.2018.06.002 [CrossRef] PMID:29890164
- Kalevar A, Dollin M, Gupta RR. Opacification of scleral-sutured Akreos AO60 intraocular lens after vitrectomy with gas tamponade: case series. Retin Cases Brief Rep. 2020;14(2):174–177. doi:10.1097/ICB.0000000000000634 [CrossRef] PMID:28957955
- Giers BC, Tandogan T, Auffarth GU, et al. Hydrophilic intraocular lens opacification after posterior lamellar keratoplasty - a material analysis with special reference to optical quality assessment. BMC Ophthalmol. 2017;17(1):150. doi:10.1186/s12886-017-0546-8 [CrossRef] PMID:28830376
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Demographics and Ophthalmologic Findings (32 Eyes of 31 Cases)
|Age (Years)||57.0 ± 13.5|
|Gender||Female (n; %)||12; 38.7|
|Male (n; %)||19; 61.3|
|Posterior capsule||Intact (n; %)||16; 50.0|
|Ruptured (n; %)||9; 28.1|
|YAG-laser capsulotomy (n; %)||7; 21.9|
|Period between IOL implantation and RD surgery (months)||23.9 ± 21.2|
|Period between YAG-laser capsulotomy and RD surgery (months) (n=7)||3.7 ± 2.9|
|Recurrence of RD (n; %)||3; 9.4|
|Total duration for SO tamponade (months)||4.6 ± 2.0|
|Period between IOL implantation and the diagnosis of IOLo (months)||51.2 ± 27.4|
|Period between RD surgery and the diagnosis of IOLo (months)||27.4 ± 18.3|
|Period between SOR and the diagnosis of IOLo (months) (n=30)||22.0 ± 18.6|
|Mean BCVA at the postoperative first month visit of SOR (ETDRS)||20/61 ± 20/87|
|Mean BCVA at the time of IOLo diagnosis (ETDRS)||20/161 ± 20/125|
|Follow-up period after the diagnosis of IOLo (months)||47.3 ± 22.1|
|Total follow-up (months)||67.0 ± 23.5|
|Patients underwent IOL exchange (n; %)||12; 37.5|
|Period between IOL implantation and exchange surgeries (months)||65.8 ± 18.6|
|Period between the diagnosis of IOLo and exchange surgery (months)||12.8 ± 10.5|
|Explanted IOLs (n; %) Hydrophilic acrylic material Hydrophilic acrylic material coated with hydrophobic surface||11; 91.71; 8.3|
|Implanted IOL type in exchange surgery Placed inside the capsular bag (n; %) Placed in the ciliary sulcus (n; %)||Acrysof MA60AC6; 50.06; 50.0|
|Follow-up period after IOL exchange surgery (months)||30.8 ± 16.2|
|Mean BCVA at the postoperative first month visit of SOR (ETDRS)||20/50 ± 20/124|
|Mean BCVA at the time of IOLo diagnosis (ETDRS)||20/700 ± 20/529|
|Mean BCVA at the last follow-up visit (ETDRS)||20/63 ± 20/88|