692
LETTERS
acetonide in that it enhanced aqueous reaction reduction and thus improved the postoperative CDVA.” Regarding postoperative intraocular pressure (IOP) reduction, the authors said that IOP decreased significantly after surgery in all patients with no significant difference between the intracameral triamcinolone acetonide treatment group and the control group, which means the IOP reduction was seen even in the group not receiving intracameral triamcinolone acetonide. They also said “our study has also found that the intracameral injection of triamcinolone acetonide resulted in effective IOP control.” These 2 statements appear contradictory and confusing. We hope surgeons will not begin to practice intracameral triamcinolone acetonide injection for control of IOP. In phacotrabeculectomy, there are more parameters to look at than CDVA, IOP, and postoperative inflammation (anterior chamber cells and flare). How about the bleb morphology and vascularity, which the authors did not mention? It would be enlightening to know the effect of intracameral triamcinolone acetonide on the bleb status and healing response. Tiakumzuk Sangtam, MS, MMed(Ophth), FRCSEd Singapore Andr e Mermoud, MD Lausanne, Switzerland
REFERENCES 1. Wang B, Dong N, Xu B, Liu J, Xiao L. Efficacy and safety of intracameral triamcinolone acetonide to control postoperative inflammation after phacotrabeculectomy. J Cataract Refract Surg 2013; 39:1691–1697 € m M. Outcomes of cataract surgery. In: Yanoff M, 2. Lundstro Duker JS, eds, Ophthalmology, 3rd ed. St. Louis, MO, Mosby Elsevier, 2009; 493–496
Reply : According to our results, at 1, 7, and 14 days after surgery, the 3 groups treated with triamcinolone acetonide, especially Group B (triamcinolone acetonide 1.0 mg), showed better CDVA than the control group and the difference was sustained up to 28 days. We therefore concluded that the use of intracameral triamcinolone acetonide injection can improve postoperative visual acuity. At the same time, we have observed postoperative anterior chamber cells and anterior chamber flare. We found that the groups treated with triamcinolone acetonide showed fewer anterior chamber cells and less flare than the control group. This trend was consistent with that of CDVA. We clearly know that postoperative visual acuity depends on many factors, but combining all the information, it is reasonable to say that triamcinolone acetonide injected directly into the
anterior chamber during the surgery reduced postoperative anterior segment inflammation and improved postoperative visual acuity. Our main purpose was to study the efficacy of intracameral triamcinolone acetonide in controlling inflammation after phacotrabeculectomy. After this effect has been confirmed, we should also make sure that IOP can be well controlled, otherwise the use of triamcinolone acetonide is meaningless. Please note that we stated intracameral injection of triamcinolone acetonide resulted in effective IOP control. We did not expect that triamcinolone acetonide injection could result in better IOP control. This study is a preliminary one. The short follow-up time was a major limitation. We agree that there are some margins for further investigation. A subsequent study with longer follow-up and more parameters is underway. Since triamcinolone acetonide is a corticosteroid with marked antifibrosis action, there is reason to speculate that triamcinolone acetonide injected directly into the anterior chamber can achieve a better functional bleb and IOP control in the long run.dBirdsong Wang, PhD, Lin Xiao, PhD
Hydrodissection techniques during femtosecond laser–assisted cataract surgery We believe the methodology and discussion in the article by Daya et al.1 may have led to the erroneous conclusion that conventional hydrodissection performed during laser-assisted cataract surgery is more difficult to perform and should be abandoned. The authors base their recommendation on the outcomes of the first 9 laser-assisted cataract surgery cases performed. The difficulty finding the subcapsular space and performing hydrodissection is not representative of the general surgical experience with laser cataract surgery but rather suggests difficulty during the learning curve. Do Daya et al. believe the problem of cortical hydration and subsequent difficulty accessing the subcapsular space is related to the energy and capsulotomy offset parameters they were using or is it something specific to the Victus system (Bausch & Lomb, Inc.)? The statistical comparison of no hydrodissection, conventional hydrodissection, and translenticular hydrodissection can be challenged as one would have to question whether conventional hydrodissection was performed adequately, particularly as Daya et al. acknowledged difficulty with the technique. They report a high incidence of radial anterior capsule tears (3 in the first 9 cases), which they attribute to capsular block syndrome (CBS); however, the explanation does not support that conclusion. Daya et al. comment on difficulty achieving hydrodissection
J CATARACT REFRACT SURG - VOL 40, APRIL 2014
LETTERS
(with little or no fluid injected into the bag and inadequate mobilization of the crystalline lens), yet the conclusion reached is that the radial tears were due to over-inflation of the bag, resulting in CBS and stretching of the capsulotomy edge. The surgical description suggests it is more likely that a capsule tag or defect tore posteriorly because of intraoperative manipulation. The attached video suggests the difficulties described are due to the hydrodissection technique rather than CBS. The injected fluid does not appear to be directed in the subcapsular space but rather overfills the anterior chamber. There is no evidence of the “pupil snap” sign suggestive of CBS.2 Defining CBS as any case of capsule distension, hydration of lens cortex, partial hydro-prolapse, or forward movement of the cataract following injection of hydrodissection fluid is too broad and does not reflect the more serious sequelae of intraoperative CBS (posterior capsule rupture and subluxated or dropped nucleus). The 2 cases of CBS we reported in our early series occurred following otherwise simple and uneventful hydrodissection.3 The increased capsule volume due to laser-generated gas was a contributing factor, not pneumodissection, which can be advantageous in some cases by allowing the surgeon to mobilize and remove the lens fragments without hydrodissection. Our group has not encountered any of the problems Daya et al. report with hydrodissection.4 Injecting balanced salt solution or an ophthalmic viscosurgical device into the laser-fragmented cataract to separate the segments is a technique we explored early; however, cortical cleavage is unlikely to be adequately achieved and posterior capsule opacification rates would have to be studied to show that translenticular hydrodissection is not associated with a higher rate. Although some surgeons have been cautious with hydrodissection in the early stages of converting to laser-assisted cataract surgery due to the report of intraoperative CBS, we do not believe hydrodissection should be abandoned because of fear of CBS or an erroneous belief that it cannot be performed safely. We have found laser-assisted cataract surgery to be very safe and effective and have not seen another case of CBS in our facility in more than 3500 cases. Timothy V. Roberts, MB BS, MMed, FRANZCO, FRACS Michael Lawless, MB BS, FRANZCO, FRACS Gerard Sutton, MB BS, MD, FRANZCO, FRACS Chris Hodge, BAppSc(Orth) Sydney, Australia Dr. Lawless is a member of the medical advisory board of Alcon Lensx, Inc.
693
REFERENCES 1. Daya SM, Nanavaty MA, Espinosa-Lagana MM. Translenticular hydrodissection, lens fragmentation, and influence on ultrasound power in femtosecond laser–assisted cataract surgery and refractive lens exchange. J Cataract Refract Surg 2014; 40:37–43 2. Yeoh R. The ‘pupil snap’ sign of posterior capsule rupture with hydrodissection in phacoemulsification [letter]. Br J Ophthalmol 1996; 80:486. Available at: http://www.ncbi.nlm.nih.gov/pmc/ articles/PMC505505/pdf/brjopthal00005-0106b.pdf. Accessed January 7, 2014 3. Roberts TV, Sutton G, Lawless MA, Jindal-Bali S, Hodge C. Capsular block syndrome associated with femtosecond laser– assisted cataract surgery. J Cataract Refract Surg 2011; 37:2068–2070 4. Roberts TV, Lawless M, Bali SJ, Hodge C, Sutton G. Surgical outcomes and safety of femtosecond laser cataract surgery; a prospective study of 1500 consecutive cases. Ophthalmology 2013; 120:227–233
Reply : The purpose of our recent article was to describe an alternative technique for hydrodissection as well as the benefits of femtosecond laser–assisted cataract surgery using the Victus femtosecond laser platform. We disagree with Dr. Roberts et al. in several areas, including the suggestion that our publication in any way leads to the erroneous conclusion that conventional hydrodissection performed during laserassisted cataract surgery should be abandoned. We are aware of many colleagues who regularly perform hydrodissection without complications. We believe that conventional hydrodissection is more difficult to perform in laser-assisted cataract surgery because of cortical changes and adhesions to the anterior capsule and, similar to Roberts et al. in their own publication,1 consider there to be a potential for CBS and posterior capsule rupture. This severe complication can be avoided using modifications in technique or the alternative technique of translenticular hydrodissection. Dr. Roberts et al. suggest that our manuscript compared outcomes of no hydrodissection, conventional hydrodissection, and translenticular hydrodissection. This is absolutely not the case. In reference to hydrodissection, the paper describes the statistical analysis of only 2 groups: no hydrodissection and translenticular hydrodissection, the results of which are summarized in our Table 2. The 9 cases in which conventional hydrodissection was performed were included in the no-hydrodissection group. Before addressing further the comments made regarding hydrodissection, it is useful to review CBS as described by Miyake et al.,2 who classified capsular block into 3 categories: intraoperative, early postoperative, and late postoperative. Miyake et al. describe intraoperative capsular block as follows: “This type is caused by rapid hydrodissection using a large amount of balanced salt solution.” They go on to state that the
J CATARACT REFRACT SURG - VOL 40, APRIL 2014
LETTERS
acetonide in that it enhanced aqueous reaction reduction and thus improved the postoperative CDVA.” Regarding postoperative intraocular pressure (IOP) reduction, the authors said that IOP decreased significantly after surgery in all patients with no significant difference between the intracameral triamcinolone acetonide treatment group and the control group, which means the IOP reduction was seen even in the group not receiving intracameral triamcinolone acetonide. They also said “our study has also found that the intracameral injection of triamcinolone acetonide resulted in effective IOP control.” These 2 statements appear contradictory and confusing. We hope surgeons will not begin to practice intracameral triamcinolone acetonide injection for control of IOP. In phacotrabeculectomy, there are more parameters to look at than CDVA, IOP, and postoperative inflammation (anterior chamber cells and flare). How about the bleb morphology and vascularity, which the authors did not mention? It would be enlightening to know the effect of intracameral triamcinolone acetonide on the bleb status and healing response. Tiakumzuk Sangtam, MS, MMed(Ophth), FRCSEd Singapore Andr e Mermoud, MD Lausanne, Switzerland
REFERENCES 1. Wang B, Dong N, Xu B, Liu J, Xiao L. Efficacy and safety of intracameral triamcinolone acetonide to control postoperative inflammation after phacotrabeculectomy. J Cataract Refract Surg 2013; 39:1691–1697 € m M. Outcomes of cataract surgery. In: Yanoff M, 2. Lundstro Duker JS, eds, Ophthalmology, 3rd ed. St. Louis, MO, Mosby Elsevier, 2009; 493–496
Reply : According to our results, at 1, 7, and 14 days after surgery, the 3 groups treated with triamcinolone acetonide, especially Group B (triamcinolone acetonide 1.0 mg), showed better CDVA than the control group and the difference was sustained up to 28 days. We therefore concluded that the use of intracameral triamcinolone acetonide injection can improve postoperative visual acuity. At the same time, we have observed postoperative anterior chamber cells and anterior chamber flare. We found that the groups treated with triamcinolone acetonide showed fewer anterior chamber cells and less flare than the control group. This trend was consistent with that of CDVA. We clearly know that postoperative visual acuity depends on many factors, but combining all the information, it is reasonable to say that triamcinolone acetonide injected directly into the
anterior chamber during the surgery reduced postoperative anterior segment inflammation and improved postoperative visual acuity. Our main purpose was to study the efficacy of intracameral triamcinolone acetonide in controlling inflammation after phacotrabeculectomy. After this effect has been confirmed, we should also make sure that IOP can be well controlled, otherwise the use of triamcinolone acetonide is meaningless. Please note that we stated intracameral injection of triamcinolone acetonide resulted in effective IOP control. We did not expect that triamcinolone acetonide injection could result in better IOP control. This study is a preliminary one. The short follow-up time was a major limitation. We agree that there are some margins for further investigation. A subsequent study with longer follow-up and more parameters is underway. Since triamcinolone acetonide is a corticosteroid with marked antifibrosis action, there is reason to speculate that triamcinolone acetonide injected directly into the anterior chamber can achieve a better functional bleb and IOP control in the long run.dBirdsong Wang, PhD, Lin Xiao, PhD
Hydrodissection techniques during femtosecond laser–assisted cataract surgery We believe the methodology and discussion in the article by Daya et al.1 may have led to the erroneous conclusion that conventional hydrodissection performed during laser-assisted cataract surgery is more difficult to perform and should be abandoned. The authors base their recommendation on the outcomes of the first 9 laser-assisted cataract surgery cases performed. The difficulty finding the subcapsular space and performing hydrodissection is not representative of the general surgical experience with laser cataract surgery but rather suggests difficulty during the learning curve. Do Daya et al. believe the problem of cortical hydration and subsequent difficulty accessing the subcapsular space is related to the energy and capsulotomy offset parameters they were using or is it something specific to the Victus system (Bausch & Lomb, Inc.)? The statistical comparison of no hydrodissection, conventional hydrodissection, and translenticular hydrodissection can be challenged as one would have to question whether conventional hydrodissection was performed adequately, particularly as Daya et al. acknowledged difficulty with the technique. They report a high incidence of radial anterior capsule tears (3 in the first 9 cases), which they attribute to capsular block syndrome (CBS); however, the explanation does not support that conclusion. Daya et al. comment on difficulty achieving hydrodissection
J CATARACT REFRACT SURG - VOL 40, APRIL 2014
LETTERS
(with little or no fluid injected into the bag and inadequate mobilization of the crystalline lens), yet the conclusion reached is that the radial tears were due to over-inflation of the bag, resulting in CBS and stretching of the capsulotomy edge. The surgical description suggests it is more likely that a capsule tag or defect tore posteriorly because of intraoperative manipulation. The attached video suggests the difficulties described are due to the hydrodissection technique rather than CBS. The injected fluid does not appear to be directed in the subcapsular space but rather overfills the anterior chamber. There is no evidence of the “pupil snap” sign suggestive of CBS.2 Defining CBS as any case of capsule distension, hydration of lens cortex, partial hydro-prolapse, or forward movement of the cataract following injection of hydrodissection fluid is too broad and does not reflect the more serious sequelae of intraoperative CBS (posterior capsule rupture and subluxated or dropped nucleus). The 2 cases of CBS we reported in our early series occurred following otherwise simple and uneventful hydrodissection.3 The increased capsule volume due to laser-generated gas was a contributing factor, not pneumodissection, which can be advantageous in some cases by allowing the surgeon to mobilize and remove the lens fragments without hydrodissection. Our group has not encountered any of the problems Daya et al. report with hydrodissection.4 Injecting balanced salt solution or an ophthalmic viscosurgical device into the laser-fragmented cataract to separate the segments is a technique we explored early; however, cortical cleavage is unlikely to be adequately achieved and posterior capsule opacification rates would have to be studied to show that translenticular hydrodissection is not associated with a higher rate. Although some surgeons have been cautious with hydrodissection in the early stages of converting to laser-assisted cataract surgery due to the report of intraoperative CBS, we do not believe hydrodissection should be abandoned because of fear of CBS or an erroneous belief that it cannot be performed safely. We have found laser-assisted cataract surgery to be very safe and effective and have not seen another case of CBS in our facility in more than 3500 cases. Timothy V. Roberts, MB BS, MMed, FRANZCO, FRACS Michael Lawless, MB BS, FRANZCO, FRACS Gerard Sutton, MB BS, MD, FRANZCO, FRACS Chris Hodge, BAppSc(Orth) Sydney, Australia Dr. Lawless is a member of the medical advisory board of Alcon Lensx, Inc.
693
REFERENCES 1. Daya SM, Nanavaty MA, Espinosa-Lagana MM. Translenticular hydrodissection, lens fragmentation, and influence on ultrasound power in femtosecond laser–assisted cataract surgery and refractive lens exchange. J Cataract Refract Surg 2014; 40:37–43 2. Yeoh R. The ‘pupil snap’ sign of posterior capsule rupture with hydrodissection in phacoemulsification [letter]. Br J Ophthalmol 1996; 80:486. Available at: http://www.ncbi.nlm.nih.gov/pmc/ articles/PMC505505/pdf/brjopthal00005-0106b.pdf. Accessed January 7, 2014 3. Roberts TV, Sutton G, Lawless MA, Jindal-Bali S, Hodge C. Capsular block syndrome associated with femtosecond laser– assisted cataract surgery. J Cataract Refract Surg 2011; 37:2068–2070 4. Roberts TV, Lawless M, Bali SJ, Hodge C, Sutton G. Surgical outcomes and safety of femtosecond laser cataract surgery; a prospective study of 1500 consecutive cases. Ophthalmology 2013; 120:227–233
Reply : The purpose of our recent article was to describe an alternative technique for hydrodissection as well as the benefits of femtosecond laser–assisted cataract surgery using the Victus femtosecond laser platform. We disagree with Dr. Roberts et al. in several areas, including the suggestion that our publication in any way leads to the erroneous conclusion that conventional hydrodissection performed during laserassisted cataract surgery should be abandoned. We are aware of many colleagues who regularly perform hydrodissection without complications. We believe that conventional hydrodissection is more difficult to perform in laser-assisted cataract surgery because of cortical changes and adhesions to the anterior capsule and, similar to Roberts et al. in their own publication,1 consider there to be a potential for CBS and posterior capsule rupture. This severe complication can be avoided using modifications in technique or the alternative technique of translenticular hydrodissection. Dr. Roberts et al. suggest that our manuscript compared outcomes of no hydrodissection, conventional hydrodissection, and translenticular hydrodissection. This is absolutely not the case. In reference to hydrodissection, the paper describes the statistical analysis of only 2 groups: no hydrodissection and translenticular hydrodissection, the results of which are summarized in our Table 2. The 9 cases in which conventional hydrodissection was performed were included in the no-hydrodissection group. Before addressing further the comments made regarding hydrodissection, it is useful to review CBS as described by Miyake et al.,2 who classified capsular block into 3 categories: intraoperative, early postoperative, and late postoperative. Miyake et al. describe intraoperative capsular block as follows: “This type is caused by rapid hydrodissection using a large amount of balanced salt solution.” They go on to state that the
J CATARACT REFRACT SURG - VOL 40, APRIL 2014
