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QUESTION

WHAT TYPE OF INTRAOCULAR LENS SHOULD BE CONSIDERED IN AN EYE WITH VITREORETINAL DISEASE?

Marina Gilca, MD
Kourous A. Rezaei, MD

It is well-documented that vitreous surgery leads to the progression of crystalline lens opacity. This is not a complication of vitrectomy surgery, but rather a pathophysiologic response to removal of the vitreous gel. The etiology of cataract formation after vitreoretinal surgery is not completely known; however, it has been reported that vitreous removal leads to increased oxygen tension in the posterior segment, resulting in oxidative damage and cataract progression.¹ We inform all of our phakic patients that they will likely need cataract surgery after vitrectomy surgery. The timing of the cataract surgery varies according to the degree of preexisting cataract, the indication for vitrectomy, the use of intraocular tamponade (type of gas bubble or silicone oil), and the patient’s compliance with positioning.

Because cataract surgery is practically inevitable after vitreous surgery, we generally recommend cataract surgery prior to vitrectomy surgery for nonurgent vitreoretinal cases. This is based on the following reasons:

• Cataract surgery is generally considered easier to perform prior to vitrectomy surgery because the vitreous gel provides intraoperative support of the crystalline lens.
  
• If a complication develops during cataract surgery, the patient is already scheduled for vitrectomy surgery.
  
• An intraocular lens (IOL) generally offers a superior view during vitreous surgery when compared to an aged natural lens.
  
• Pseudophakic status allows for more thorough peripheral vitreous shaving.
  
• Inspection of the peripheral retina during vitreoretinal surgery is easier in pseudophakic eyes.

Polymethylmethacrylate was the first material to be used for an IOL. Current IOLs are made mainly from silicone or acrylic. In eyes with retinal pathology, cataract surgeons should avoid using silicone lenses because some complex retinal procedures may require silicone oil tamponade. Silicone oil droplets adhere irreversibly to silicone IOLs (in the presence of a posterior capsular opening), leading to a poor view of the fundus and reduced visual acuity.2 These patients would likely need to have the IOL exchanged. This contraindication for silicone IOLs holds true for eyes with a history of silicone oil removal because silicone oil removal is never complete. The emulsified oil droplets that remain in a fluid-filled eye may adhere to the secondarily implanted silicone IOL, likely leading to reduced vision. We prefer the implantation of acrylic lenses in eyes that may need a retinal procedure in the future.

Hydrophobic IOL implants may sometimes lead to the development of glistenings: fluid-filled microvacuoles resulting from aqueous humor inflow into the IOL material.³ Although small amounts of glistening are often unnoticed by patients and examiners, a significant amount of glistenings may occasionally impact visual acuity, contrast sensitivity, and fundus visualization during clinical exam or surgery.⁴ Glistenings may worsen over time, making IOL explantation more challenging.⁴ The material composition of the IOL’s optic is the only currently identified risk factor for the development of glistenings.

Hydrophilic IOLs have been reported to calcify after air and/or gas exposure or breakdown of the blood-aqueous barrier and/or inflammation during intraocular surgery.⁵ Some cases of IOL calcification occur only in the area that is directly exposed to air and/or gas, such as the anterior surface of IOL after Descemet stripping automated endothelial keratoplasty surgery.⁶ However, IOL calcification has also been reported after uncomplicated penetrating keratoplasty or vitrectomy surgery without air/gas exposure.⁷ Diabetic patients seem to have higher rates of calcification, which may be due to metabolic changes in the composition of the aqueous humor in these patients.^7,8 The Akreos Advanced Optics IOL (Bausch + Lomb), a scleral-sutured IOL, has recently become popular due to its ease of implantation and suturing; however, given its hydrophilicity, it may become calcified, and therefore may not be the optimal IOL for patients with diabetes or patients who may potentially require surgery with air or gas tamponade.⁸

We and others have reported that blue light-filtering IOLs may be beneficial in eyes that are at high risk for progression of age-related macular degeneration.^9–11 A randomized controlled clinical trial evaluated whether the yellow tint of a blue light-filtering IOL interferes with the surgeon’s ability to perform vitreoretinal maneuvers.¹² Sixty patients were enrolled in this trial, and none of the surgeons reported any adverse events due to the presence of the blue light-filtering lens. No modification of the surgical set-up or procedure was required during vitreoretinal surgery.

Presbyopia-correcting IOLs currently on the market correct for both near and distance. A recent article reviewed the 2 commonly used presbyopia-correcting lenses: Crystalens and ReSTOR.¹³ Crystalens is an accommodating silicone monofocal lens and is therefore contraindicated in eyes that may need vitrectomy surgery. The ReSTOR and Tecnis Multifocal are acrylic multifocal lenses and the Symfony is an extended depth of focus IOL. The accurate positioning of these lenses in the bag (single piece) or sulcus (3 piece) is crucial for its optimal performance. During vitreoretinal surgery, the eye may be filled with air or gas, which has the potential to decenter the lens from its original location. The same complication may occur in patients with toric IOLs. Multifocal and extended depth of focus lenses may induce aberrations that can interfere with intraoperative visualization of the retina. This can be especially bothersome to the vitreoretinal surgeon during membrane peeling. In addition, one may also need to refocus the microscope when operating from the posterior pole to the periphery. Patients with macular pathology therefore may not be appropriate candidates for such premium lenses. It may also be reasonable to perform optical coherence tomography in patients for whom subtle macular pathology cannot be ruled out in the setting of a significant cataract.

1.     Holekamp NM, Shui YB, Beebe DC. Vitrectomy surgery increases oxygen exposure to the lens: a possible mechanism for nuclear cataract formation. Am J Ophthalmol. 2005;139(2):302-310.

2.     Khawly JA, Lambert RJ, Jaffe GJ. Intraocular lens changes after short- and long-term exposure to intraocular silicone oil: an in vivo study. Ophthalmology. 1998;105(7):1227-1233.

3.     Gregori NZ, Spencer TS, Mamalis N, Olson RJ. In vitro comparison of glistening formation among hydrophobic acrylic intraocular lenses(1). J Cataract Refract Surg. 2002;28(7):1262-1268.

4.     Christiansen G, Durcan FJ, Olson RJ, Christiansen K. Glistenings in the AcrySof intraocular lens: pilot study. J Cataract Refract Surg. 2001;27:728–733.

5.     Neuhann IM, Neuhann TF, Rohrbach JM. Intraocular lens calcification after keratoplasty. Cornea. 2013;32(4):e6-10.

6.     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.

7.     Cao D, Zhang H, Yang C, Zhang L. Akreos Adapt AO intraocular lens opacification after vitrectomy in a diabetic patient: a case report and review of the literature. BMC Ophthalmol. 2016;16:82.

8.     Park DH, Shin JP, Kim HK, Kim JH, Kim SY. Hydrophilic acrylic intraocular lens (Akreos AO MI60) optic opacification in patients with diabetic retinopathy. Br J Ophthalmol. 2010;94(12):1688-1689.

9.     Sparrow JR, Miller AS, Zhou J. Blue light-absorbing intraocular lens and retinal pigment epithelium protection in vitro. J Cataract Refract Surg. 2004;30(4):873-878.

10.   Marshall J, Cionni RJ, Davison J, et al. Clinical results of the blue-light filtering AcrySof Natural foldable acrylic intraocular lens. J Cataract Refract Surg. 2005;31(12):2319-2323.

11.   Rezaei KA, Gasyna E, Seagle BL, Norris JR Jr, Rezaei KA. AcrySof natural filter decreases blue light-induced apoptosis in human retinal pigment epithelium. Graefes Arch Clin Exp Ophthalmol. 2008;246(5):671-676.

12.   Falkner-Radler CI, Benesch T, Binder S. Blue light-filter intraocular lenses in vitrectomy combined with cataract surgery: results of a randomized controlled clinical trial. Am J Ophthalmol. 2008;145(3):499-503.

13.   Tewari A, Shah GK. Presbyopia-correcting intraocular lenses: what retinal surgeons should know. Retina. 2008;28(4):535-537.

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