Eyeworld

EW RETINA 154 April 2017 by Timothy W. Olsen, MD Timing intravitreal anti-VEGF AMD injections and cataract surgery A ge-related macular de- generation (AMD) is a leading cause of irrevers- ible blindness in many popultions. 1–9 Other common aging disorders include cataract and glaucoma. 3,4,8,10 Current standards of care for the manage- ment of exudative AMD include the use of monthly, or less frequent, anti-vascular endothelial growth factor (VEGF) agents. 11–16 Globally, the group of individuals over age 60 is increasing rapidly, especially in developing countries. 17 Thus, there is a growing and expanding popu- lation that will need to be managed for both AMD and cataracts. Since most patients receiving anti-VEGF injections require recurrent injec- tions in order to maintain macular integrity and visual acuity, clinicians need to risk-assess and determine the best timing for cataract surgery during such active periods of exuda- tive AMD. The initial question in the management of wet AMD and deter- mining the risk–benefit of cataract surgery is to assess the possible visual acuity benefit versus poten- tial harm from cataract surgery. tion. Much of this data is obtained from animal studies. We know from rabbit studies, that bevacizumab remains in the vitreous longer than ranibizumab. 19,20 In our lab, using the pig model that has vitreous and retinal blood flow similar to humans, we found that intravitreal bevacizumab had a steady, linear decline over 30 to 60 days when compared as a ratio to tissue protein levels in the vitreous. 21 These levels are supported by corresponding serum data collected from premature infants being treated with bevaci- zumab for retinopathy of prematu- rity. 22 Also, we know from many of the wet AMD studies that redosing is required between 30 to 60 days in active wet AMD. The pharmacoki- netics for intravitreal pulse dosing can also can be plotted over time with peaks and valleys. Thus, should cataract surgery be indicated, then adjusting the timing of surgery to recognize this pulse therapy should be actively managed. For some wet AMD patients, injections are required monthly, while others may follow a treat-and-extend protocol and may only require injections every 2 to 3 months. The available literature to guide management of wet AMD and cat- aract surgery is limited. Some early studies suggest that the anti-VEGF agents may be given either at the time of cataract surgery 23,24 or up to 1 month after cataract surgery with- out adversely affecting the outcomes of AMD treatment. 25,26 Considering the pharmacokinetics of intravit- real pulse therapy and combining this with the dynamics of cataract surgery, the logical approach would be to deliver the anti-VEGF agent, then allow the maximum thera- peutic effect of the agent to occur, perhaps 2 to 4 weeks. Next, cataract surgery could be planned during this interval (2–4 weeks) following the anti-VEGF injection. During surgery, the fluid irrigation will likely reduce the intravitreal drug concentration further than would have occurred without surgery. Re-injecting soon after cataract surgery may com- promise the cataract wound. By allowing approximately 2 weeks for the cataract wound to stabilize, then re-injecting, one would hope to quickly restore loading-dose efficacy. One could then return to the pre-cataract surgery injection frequency for subsequent anti-VEGF injections. An alternative would be for the cataract surgeon to inject at the time of surgery. Some surgeons may not feel comfortable with these simultaneous injections, and some drug may be lost through a wound leak. One final comment relates to cystoid macular edema (CME) that commonly occurs following cataract surgery. While CME may appear to temporarily worsen the OCT find- ings, it is usually transient, tempo- rary, and resolves with conservative measures. In summary, cataract surgery and AMD are both common and frequently need to be managed simultaneously. Patients should be advised that while cataract surgery may be beneficial, the AMD will progress . . . with or without cata- ract surgery. Also, the AMD-related symptoms will not improve follow- ing cataract surgery. Nevertheless, cataract surgery may be valuable by improving both visual acuity and quality of life. Timing of cata- Retina consultation corner T im Olsen, MD, has written a compre- hensive and well-referenced article addressing the common scenario of patent with both cataract and AMD. The take home points are: (1) cataract surgery does not cause AMD progression; and (2) injections of anti-VEGF agents for wet AMD and cataract surgery can proceed in parallel—there is no need to delay cataract surgery until AMD is inactive or stop injec- tions in the peri-operative period. In general, wet AMD patients who have more injections have better outcomes—treat and extend is the best injection protocol. Steve Charles, MD, Chair, ASCRS Retina Clinical Committee Color fundus of the right eye in a high-risk individual, large soft drusen, extensive drusen area, and areas of hyperpigmentation. Source: Timothy W. Olsen, MD Both AMD and cataracts may cause symptoms of reduced light sensitiv- ity, thus the need for better lighting during regular visual activities, such as reading or night driving. Howev- er, macular-specific symptoms such as metamorphopsia or scotoma will not and should not be expected to improve following cataract sur- gery. Patients should be counseled accordingly. The Age-Related Eye Disease Study, also known as AREDS, has prospectively collected data on AMD patients who have undergone cataract surgery. Based on this large, prospective clinical trial, cataract surgery does not seem to worsen the progression of AMD when compared to controls. 18 Should cataract surgery become necessary for improving visual acuity, most retina specialists will recommend avoiding the use of multifocal IOLs in these situations. The role of yellow-tint lenses re- mains controversial, with no defini- tive studies, but could be considered. The next question for the clini- cian is the timing of cataract surgery versus the timing of anti–VEGF injections. One should understand the pharmacokinetics of anti–VEGF drugs following intravitreal injec-

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