LETTERS
laser–assisted cataract surgery with its tendency to cause prostaglandin-mediated intraoperative miosis after the femtosecond laser step suggests that we should revisit the use of topical NSAIDs as part of the preoperative dilating regimen. Ronald Yeoh, FRCS Ed, FRCSG, FRCOphth Singapore Dr. Yeoh is on the speaker panel of Alcon Laboratories, Inc., and Abbott Medical Optics, Inc. REFERENCES nitz K, Gyenes A, Juha sz E, 1. Nagy ZZ, Takacs A, Filkorn T, Kra ndor GL, Kovacs I, Juha sz T, Slade S. Complications of femtoSa second laser–assisted cataract surgery. J Cataract Refract Surg 2014; 40:20–28 2. Kim SJ, Flach AJ, Jampol LM. Nonsteroidal anti-inflammatory drugs in ophthalmology. Surv Ophthalmol 2010; 55:108–133 3. Stewart R, Grosserode R, Cheetham JK, Rosenthal A. Efficacy and safety profile of ketorolac 0.5% ophthalmic solution in the prevention of surgically induced miosis during cataract surgery. Clin Ther 1999; 21:723–732
Reply : Intraoperative miosis was one of the most significant intraoperative problems and complications in the early use of femtosecond laser–assisted cataract surgery. Dr. Yeoh described the role of NSAID drops, which has almost been forgotten in recent years because of the quick and safe phacoemulsification technique.1 We have also known that during the early phase of femtosecond laser–assisted cataract surgery, intraoperative miosis was more common than during routine phacoemulsification. The possible causes are the mechanical effect of the patient interface and the role of bubble and gas formation within the anterior chamber and within the lens. We have known for some time that prostaglandins are strong bioregulatory substances with high potential within the eye and within the entire body. Prostaglandins are synthesized by the cyclooxygenase pathway, and the most important intraocular source is the nonpigmented epithelial layer of the ciliary body. Mechanical and thermal stimuli may increase the level of prostaglandins in the aqueous humor.2,3 Our working team has studied intraoperative miosis, as have other authors. Recently, Schultz et al.4 reported that the prostaglandin level is elevated in the aqueous following femtosecond laser pretreatment. The cause might be the mechanical effect of the patient interface and the bubble formation within the anterior chamber. Based on the experiences of femtosecond laser surgeons, it is strongly advised that preoperative NSAIDs be included in the dilation regimen. The personal experiences of
853
Dr. Yeoh support this recommendation. Multicenter studies of the time to start NSAIDS and dilating drops are needed; ie, the previous day, 1 hour before surgery, or as in traditional phacoemulsification, adding only NSAID drops. I always warn surgeons not to wait too long between femtosecond laser pretreatment and starting phacoemulsification. In that case, the intraoperative dilation with epinephrine is more difficult than in traditional phacoemulsification cases. We have a long journey before we can state that this new technology is safely established and surgeons can benefit from every step in its use without any compromise. Herewith, I would like to invite femtosecond laser users to establish the guidelines for preoperative pharmacology of femtosecond laser–assisted cataract surgery.dZoltan Z. Nagy, MD, PhD, DSC REFERENCES 1. Gimbel HV. The effect of treatment with topical nonsteroidal antiinflammatory drugs with and without intraoperative epinephrine on the maintenance of mydriasis during cataract surgery. Ophthalmology 1989; 96:585–588 2. Cole DF, Unger WG. Prostaglandins as mediators for the responses of the eye to trauma. Exp Eye Res 1973; 17:357–368 €fner C, Schlo € tzer-Schrehardt U, Gu €hring H, Zeilhofer HU, 3. Maiho Naumann GO, Pahl A, Mardin C, Tamm ER, Brune K. Expression of cyclooxygenase-1 and -2 in normal and glaucomatous human eyes. Invest Ophthalmol Vis Sci 2001; 42:2616–2624. Available at: http://www.iovs.org/content/42/11/2616.full.pdf. Accessed February 8, 2014 4. Schultz T, Joachim SC, Kuehn M, Dick HB. Changes in prostaglandin levels in patients undergoing femtosecond laserassisted cataract surgery. J Refract Surg 2013; 29:742–747
Sutureless intrascleral posterior chamber intraocular lens fixation In their experimental study, Akimoto et al.1 described their technique for intrascleral fixation of an intraocular lens (IOL) via a catheter. The authors stated that they achieved the aphakia by phacoemulsification following the capsulorhexis they performed but did not give information about the status of the posterior capsule. In these experimental cases, surgical maneuvers are easy to perform if the posterior capsule is intact. However, in our patients, these maneuvers are not as easy because the posterior capsule is not intact and anterior vitrectomy has also been performed. During scleral fixation, the use of a large amount of an ophthalmic viscosurgical device or a maintainer for continuous irrigation of the balanced salt solution into the eye has been necessary to prevent ocular deformation.2,3 Akimoto et al. pointed out that the corneal diameter of the pig eye was 16.5 mm and bigger than the human
J CATARACT REFRACT SURG - VOL 40, MAY 2014
854
LETTERS
eye, so the estimated placement of the sclerotomy should be the same as in a human eye (14.5 mm). We think they overlooked a point in the method. They used the same placement (14.5 mm) for both sclerotomy and the clear corneal incision (CCI) the IOL was implanted through.1 It would be more reflective of the reality in daily practice if the authors had placed the CCI between 10.5 mm and 11.5 mm because when performing these operations in human eyes, one does not work in the same plane. We agree with the authors that there are fewer intraocular maneuvers in their method. However, when applying this method to the human eye, more ocular deformation can be expected during surgery for 2 reasons. First, CCIs and sclerotomies are not in the same plane in the human eye. The other reason is the necessity of manipulations in both anterior and posterior chambers. Also, the iris tissue will be in front of the catheter during the process. It appears that Akimoto et al. were working in only the anterior chamber of the pig's eye. We think it would be more appropriate if they specified the necessity of manipulations in both anterior and posterior chambers and noted that some maneuvers involving the iris could be necessary during the procedure. Additionally, the surgeon will not see the second haptic of the IOL behind the iris while exiting from the human eye. This will cause a surgical difficulty that is not less than in previous techniques in which the haptic is held by a forceps. We think it should be kept in mind that this procedure could damage the tissues around the ciliary body if it was not performed very carefully. Remzi Karadag, MD Huseyin Bayramlar, MD Unsal Sari, MD Istanbul, Turkey REFERENCES 1. Akimoto M, Taguchi H, Takahashi T. Using catheter needles to deliver an intraocular lens for intrascleral fixation. J Cataract Refract Surg 2014; 40:179–183 2. Totan Y, Karadag R. Trocar-assisted sutureless intrascleral posterior chamber foldable intra-ocular lens fixation. Eye 2012; 26:788– 791. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/ PMC3376277/pdf/eye201219a.pdf. Accessed March 3, 2014 3. Totan Y, Karadag R. Two techniques for sutureless intrascleral posterior chamber IOL fixation. J Refract Surg 2013; 29:90–94
Reply : In our article, we demonstrated a new technique for intrascleral fixation of an IOL using catheter needles in pig eyes. Using our method, we can support the IOL haptic without an assistant's help and minimize intraocular manipulation.
Dr. Karadag and coauthors pointed out that the simulation procedure should be easy without complete removal of the lens, including the capsule, and without vitrectomy. In a few cases, we removed the capsule and performed a vitrectomy. In our experience, there were not many differences between vitrectomized and nonvitrectomized eyes, which may be one of the advantages of our method. An IOL dropped into the vitreous is a serious complication in intrascleral fixation of an IOL.1 Since the catheter needle holds the IOL haptic through the procedure in our method, the IOL can be delivered safely with or without the capsule. As we indicated, fluid leakage from the surgical wound is a potential disadvantage of our method. However, since the total surgical time was relatively short, the amount of leakage was less than we expected. Dr. Karadag and coauthors noted the problems in our method because of manipulation in both anterior and posterior chambers and possible damage of tissue behind the iris during the trailing haptic delivery. We agree with their suggestion that the surgical corneal wound should be around 11.5 mm in diameter for better simulation. In regard to the IOL suturing ab interno approach, the needle must be delivered from the anterior to the posterior chamber. The long curved needles with looped suture are often used for this purpose.2 To avoid blind penetration from the ciliary sulcus, a guiding needle is often used in combination.3 It may be difficult if a straight needle is used. We curved the catheter needle to perform the procedure easier. We also used a guiding needle to penetrate the sclera to deliver the trailing haptic from the vitreous cavity through the sclerotomy. When 2 needles are combined, the procedure is done through the pupil, not behind the iris, to minimize the needle-related complications. One may have to grasp and manipulate with a forceps in the eye; however, we had to hold only the catheter because it fixates the haptic tightly. Using pig eyes, we could observe the behavior of the needles and haptics, which cannot be observed behind the iris in human eyes. The pig eye experiments were worthwhile in this regard. It is important to keep in mind that there is potential tissue damage; however, we are comfortable with this procedure. Although use of a catheter needle, available in standard operating rooms, is an advantage of our method to avoid manipulation of the catheter needles and minimize the potential tissue damages, we have asked several companies about making modified blunt-end catheter-like needles. We have improved our method with each clinical experience and believe the current technique is very manageable. We are preparing a clinical
J CATARACT REFRACT SURG - VOL 40, MAY 2014
laser–assisted cataract surgery with its tendency to cause prostaglandin-mediated intraoperative miosis after the femtosecond laser step suggests that we should revisit the use of topical NSAIDs as part of the preoperative dilating regimen. Ronald Yeoh, FRCS Ed, FRCSG, FRCOphth Singapore Dr. Yeoh is on the speaker panel of Alcon Laboratories, Inc., and Abbott Medical Optics, Inc. REFERENCES nitz K, Gyenes A, Juha sz E, 1. Nagy ZZ, Takacs A, Filkorn T, Kra ndor GL, Kovacs I, Juha sz T, Slade S. Complications of femtoSa second laser–assisted cataract surgery. J Cataract Refract Surg 2014; 40:20–28 2. Kim SJ, Flach AJ, Jampol LM. Nonsteroidal anti-inflammatory drugs in ophthalmology. Surv Ophthalmol 2010; 55:108–133 3. Stewart R, Grosserode R, Cheetham JK, Rosenthal A. Efficacy and safety profile of ketorolac 0.5% ophthalmic solution in the prevention of surgically induced miosis during cataract surgery. Clin Ther 1999; 21:723–732
Reply : Intraoperative miosis was one of the most significant intraoperative problems and complications in the early use of femtosecond laser–assisted cataract surgery. Dr. Yeoh described the role of NSAID drops, which has almost been forgotten in recent years because of the quick and safe phacoemulsification technique.1 We have also known that during the early phase of femtosecond laser–assisted cataract surgery, intraoperative miosis was more common than during routine phacoemulsification. The possible causes are the mechanical effect of the patient interface and the role of bubble and gas formation within the anterior chamber and within the lens. We have known for some time that prostaglandins are strong bioregulatory substances with high potential within the eye and within the entire body. Prostaglandins are synthesized by the cyclooxygenase pathway, and the most important intraocular source is the nonpigmented epithelial layer of the ciliary body. Mechanical and thermal stimuli may increase the level of prostaglandins in the aqueous humor.2,3 Our working team has studied intraoperative miosis, as have other authors. Recently, Schultz et al.4 reported that the prostaglandin level is elevated in the aqueous following femtosecond laser pretreatment. The cause might be the mechanical effect of the patient interface and the bubble formation within the anterior chamber. Based on the experiences of femtosecond laser surgeons, it is strongly advised that preoperative NSAIDs be included in the dilation regimen. The personal experiences of
853
Dr. Yeoh support this recommendation. Multicenter studies of the time to start NSAIDS and dilating drops are needed; ie, the previous day, 1 hour before surgery, or as in traditional phacoemulsification, adding only NSAID drops. I always warn surgeons not to wait too long between femtosecond laser pretreatment and starting phacoemulsification. In that case, the intraoperative dilation with epinephrine is more difficult than in traditional phacoemulsification cases. We have a long journey before we can state that this new technology is safely established and surgeons can benefit from every step in its use without any compromise. Herewith, I would like to invite femtosecond laser users to establish the guidelines for preoperative pharmacology of femtosecond laser–assisted cataract surgery.dZoltan Z. Nagy, MD, PhD, DSC REFERENCES 1. Gimbel HV. The effect of treatment with topical nonsteroidal antiinflammatory drugs with and without intraoperative epinephrine on the maintenance of mydriasis during cataract surgery. Ophthalmology 1989; 96:585–588 2. Cole DF, Unger WG. Prostaglandins as mediators for the responses of the eye to trauma. Exp Eye Res 1973; 17:357–368 €fner C, Schlo € tzer-Schrehardt U, Gu €hring H, Zeilhofer HU, 3. Maiho Naumann GO, Pahl A, Mardin C, Tamm ER, Brune K. Expression of cyclooxygenase-1 and -2 in normal and glaucomatous human eyes. Invest Ophthalmol Vis Sci 2001; 42:2616–2624. Available at: http://www.iovs.org/content/42/11/2616.full.pdf. Accessed February 8, 2014 4. Schultz T, Joachim SC, Kuehn M, Dick HB. Changes in prostaglandin levels in patients undergoing femtosecond laserassisted cataract surgery. J Refract Surg 2013; 29:742–747
Sutureless intrascleral posterior chamber intraocular lens fixation In their experimental study, Akimoto et al.1 described their technique for intrascleral fixation of an intraocular lens (IOL) via a catheter. The authors stated that they achieved the aphakia by phacoemulsification following the capsulorhexis they performed but did not give information about the status of the posterior capsule. In these experimental cases, surgical maneuvers are easy to perform if the posterior capsule is intact. However, in our patients, these maneuvers are not as easy because the posterior capsule is not intact and anterior vitrectomy has also been performed. During scleral fixation, the use of a large amount of an ophthalmic viscosurgical device or a maintainer for continuous irrigation of the balanced salt solution into the eye has been necessary to prevent ocular deformation.2,3 Akimoto et al. pointed out that the corneal diameter of the pig eye was 16.5 mm and bigger than the human
J CATARACT REFRACT SURG - VOL 40, MAY 2014
854
LETTERS
eye, so the estimated placement of the sclerotomy should be the same as in a human eye (14.5 mm). We think they overlooked a point in the method. They used the same placement (14.5 mm) for both sclerotomy and the clear corneal incision (CCI) the IOL was implanted through.1 It would be more reflective of the reality in daily practice if the authors had placed the CCI between 10.5 mm and 11.5 mm because when performing these operations in human eyes, one does not work in the same plane. We agree with the authors that there are fewer intraocular maneuvers in their method. However, when applying this method to the human eye, more ocular deformation can be expected during surgery for 2 reasons. First, CCIs and sclerotomies are not in the same plane in the human eye. The other reason is the necessity of manipulations in both anterior and posterior chambers. Also, the iris tissue will be in front of the catheter during the process. It appears that Akimoto et al. were working in only the anterior chamber of the pig's eye. We think it would be more appropriate if they specified the necessity of manipulations in both anterior and posterior chambers and noted that some maneuvers involving the iris could be necessary during the procedure. Additionally, the surgeon will not see the second haptic of the IOL behind the iris while exiting from the human eye. This will cause a surgical difficulty that is not less than in previous techniques in which the haptic is held by a forceps. We think it should be kept in mind that this procedure could damage the tissues around the ciliary body if it was not performed very carefully. Remzi Karadag, MD Huseyin Bayramlar, MD Unsal Sari, MD Istanbul, Turkey REFERENCES 1. Akimoto M, Taguchi H, Takahashi T. Using catheter needles to deliver an intraocular lens for intrascleral fixation. J Cataract Refract Surg 2014; 40:179–183 2. Totan Y, Karadag R. Trocar-assisted sutureless intrascleral posterior chamber foldable intra-ocular lens fixation. Eye 2012; 26:788– 791. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/ PMC3376277/pdf/eye201219a.pdf. Accessed March 3, 2014 3. Totan Y, Karadag R. Two techniques for sutureless intrascleral posterior chamber IOL fixation. J Refract Surg 2013; 29:90–94
Reply : In our article, we demonstrated a new technique for intrascleral fixation of an IOL using catheter needles in pig eyes. Using our method, we can support the IOL haptic without an assistant's help and minimize intraocular manipulation.
Dr. Karadag and coauthors pointed out that the simulation procedure should be easy without complete removal of the lens, including the capsule, and without vitrectomy. In a few cases, we removed the capsule and performed a vitrectomy. In our experience, there were not many differences between vitrectomized and nonvitrectomized eyes, which may be one of the advantages of our method. An IOL dropped into the vitreous is a serious complication in intrascleral fixation of an IOL.1 Since the catheter needle holds the IOL haptic through the procedure in our method, the IOL can be delivered safely with or without the capsule. As we indicated, fluid leakage from the surgical wound is a potential disadvantage of our method. However, since the total surgical time was relatively short, the amount of leakage was less than we expected. Dr. Karadag and coauthors noted the problems in our method because of manipulation in both anterior and posterior chambers and possible damage of tissue behind the iris during the trailing haptic delivery. We agree with their suggestion that the surgical corneal wound should be around 11.5 mm in diameter for better simulation. In regard to the IOL suturing ab interno approach, the needle must be delivered from the anterior to the posterior chamber. The long curved needles with looped suture are often used for this purpose.2 To avoid blind penetration from the ciliary sulcus, a guiding needle is often used in combination.3 It may be difficult if a straight needle is used. We curved the catheter needle to perform the procedure easier. We also used a guiding needle to penetrate the sclera to deliver the trailing haptic from the vitreous cavity through the sclerotomy. When 2 needles are combined, the procedure is done through the pupil, not behind the iris, to minimize the needle-related complications. One may have to grasp and manipulate with a forceps in the eye; however, we had to hold only the catheter because it fixates the haptic tightly. Using pig eyes, we could observe the behavior of the needles and haptics, which cannot be observed behind the iris in human eyes. The pig eye experiments were worthwhile in this regard. It is important to keep in mind that there is potential tissue damage; however, we are comfortable with this procedure. Although use of a catheter needle, available in standard operating rooms, is an advantage of our method to avoid manipulation of the catheter needles and minimize the potential tissue damages, we have asked several companies about making modified blunt-end catheter-like needles. We have improved our method with each clinical experience and believe the current technique is very manageable. We are preparing a clinical
J CATARACT REFRACT SURG - VOL 40, MAY 2014
