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Pediatric refractive surgery
letters Pediatric Refractive Surgery garwal et al.1 recently reported encouraging results using laser in situ keratomileusis (LASIK) in the management of selected cases of uniocular high myopia in pediatric eyes. Using the Staar Collamer posterior chamber phakic intraocular lens2 (IOL), Lesueur and Arne,2 in a preliminary report of 5 amblyopic eyes of patients 3 to 16 years of age, demonstrated a substantial reduction in high myopia with improved best spectaclecorrected visual acuity (BSCVA). While there is a paucity of published literature on refractive surgery in pediatric and adolescent patients, others have reported similar results with photorefractive keratectomy (PRK).3–5 I recently presented the case of a 16-year-old girl who had hyperopic LASIK to correct bilateral high hyperopia (J.M. Davidorf, MD, “LASIK for High Hyperopia in Adolescents,” presented at the Symposium on Cataract, IOL and Refractive Surgery, Boston, Massachusetts, USA, May 2000). Hyperopia is particularly amenable to surgical treatment in pediatric patients. Because hyperopia does not tend to progress through adolescence and because even moderate amounts of hyperopia are well tolerated by children, the target refractive endpoint when treating hyperopes need not (and perhaps should not) be emmetropia. My patient was glasses and contact lens intolerant with ⫹7.25 diopters (D) of hyperopia (spherical equivalent) and 20/70 uncorrected visual acuity (UCVA). Because the patient’s full correction was outside the limit of safety for hyperopic LASIK, a ⫹5.25 D correction was performed, which left the patient intentionally undercorrected with ⫹1.75 D of residual hyperopia and 20/25 UCVA. The patient is now in college, still functioning without glasses. Hyperopic phakic IOL surgery for the residual refractive error may be contemplated at a later date should the patient become symptomatic. Indications for performing refractive surgery in the pediatric and adolescent populations can be divided into 3 categories: obligatory, functional, and elective. Obligatory. Pediatric patients under 7 years of age with anisometropic amblyopia should be considered for
A
© 2000 ASCRS and ESCRS Published by Elsevier Science Inc.
refractive surgery if spectacle and contact lens intolerance develops. Treatment options would be limited to procedures capable of correcting higher amounts of myopia, hyperopia, or astigmatism. While LASIK has shown the most promise of the keratorefractive procedures for higher corrections, the requisite fixation poses centration challenges. Preliminary reports have demonstrated improved BSCVA after PRK in patients as young as 5 years old.5 In that study, the necessary sedation precluded fixation and patient cooperation, so the authors centered the ablation over the pupil with reasonable success. Because PRK may induce more corneal haze in children than in adults, LASIK has demonstrated better predictability and stability than PRK with higher corrections, and the postoperative care for the LASIK patient is considerably easier. Laser in situ keratomileusis will likely prove preferable to PRK in children under 7 years of age. In contrast to keratorefractive techniques, phakic IOLs obviate the need for patient cooperation during the procedure, and the IOLs may correct the more extreme ametropias. Additionally, phakic IOLs are exchangeable in cases of improper power calculations, sizing errors, or untoward refractive changes. Laser in situ keratomileusis or PRK may be performed subsequently should further treatment be desired.6 Because of difficulties in postoperative care in infants and younger children, a foldable phakic IOL that can be implanted through a self-sealing, astigmatically neutral incision would be recommended.2 While major potential complications of phakic IOL surgery include glaucoma, cataract formation, and even endophthalmitis, the risk of not treating a patient with dense anisometropic amblyopia is not only severe but guaranteed.7–9 Functional. Pediatric patients over the age of 7 are not at risk of developing further amblyopia, but these patients may have functional indications for having refractive surgery. Examples include contact-lens-intolerant patients with significant anisometropia, refractive accommodative esotropia, or higher corrections. Photorefractive keratectomy, LASIK, or phakic IOL surgery may enable such patients to participate in certain
LETTERS
recreational or sporting activities, which should positively affect their social development, as occurred in my patient. Elective. Patients capable of wearing contacts or who are obtaining adequate vision with glasses certainly have no medical necessity for refractive surgery. Such patients must be considered the final frontier in pediatric and adolescent refractive surgery. The need is for a procedure that is extremely safe, and the refractive effect should be adjustable, particularly in patients with myopia as myopia tends to progress through adolescence and young adulthood. While LASIK has some adjustable attributes, lifting a corneal flap years after the primary procedure is not always possible, and creating a new flap poses some risk. Additionally, the induced corneal thinning may preclude further enhancement surgery. Intacs may be useful, although its range of correction is quite low and experience with explanting the intracorneal segments after several years is limited. Phakic IOL surgery offers the potential benefits of exchangeability and the ability to perform LASIK for residual refractive errors. Adjustable IOLs may one day allow laser fine-tuning of postoperative refractive errors (R.K. Maloney, MD, J. Jethmalani, MD, C. Sandstadt, MD, et al. “Laser Adjustable IOL,” presented at the annual meeting of the International Society of Refractive Surgery, Orlando, Florida, USA, October 1999). As we gain experience with the obligatory and functional situations, the safety of keratorefractive surgery, the compatibility of phakic IOLs, and the viability and safety of periodic IOL exchanges or LASIK enhancements in pediatric eyes will be determined. After thorough clinical studies of such eyes, we may begin to consider moving into the territory of surgically correcting the more elective types of problems. JONATHAN M. DAVIDORF, MD West Hills, California, USA References 1. Agarwal A, Agarwal A, Agarwal T, et al. Results of pediatric laser in situ keratomileusis. J Cataract Refract Surg 2000; 26:684 – 689 2. Lesueur LC, Arne JL. Phakic posterior chamber lens implantation in children with high myopia. J Cataract Refract Surg 1999; 25:1571–1575 3. Singh D. Photorefractive keratectomy in pediatric patients. J Cataract Refract Surg 1995; 21:630 – 632 4. Nano HD Jr, Muzzin S, Irigaray F. Excimer laser photorefractive keratectomy in pediatric patients. J Cataract Refract Surg 1997; 23:736 –739 1568
5. Alio´ JL, Artola A, Claramonte P, et al. Photorefractive keratectomy for pediatric myopic anisometropia. J Cataract Refract Surg 1998; 24:327–330 6. Zaldivar R, Davidorf JM, Oscherow S, et al. Combined posterior chamber phakic intraocular lens and laser in situ keratomileusis: bioptics for extreme myopia. J Refract Surg 1999; 15:299 –308 7. Zaldivar R, Davidorf JM, Oscherow S. Posterior chamber phakic intraocular lens for myopia of ⫺8 to ⫺19 diopters. J Refract Surg 1998; 14:294 –305 8. Davidorf JM, Zaldivar R, Oscherow S. Posterior chamber phakic intraocular lens for hyperopia of ⫹4 to ⫹11 diopters. J Refract Surg 1998; 14:306 –311 9. Greenwald MJ, Parks MM. Amblyopia. In: Tasman W, Jaeger EA, eds, Duane’s Clinical Ophthalmology, Vol 1. Philadelphia, PA, JB Lippincott Co, 1994; 1–22
Microhooks in Phacoemulsification e have read the article by Lee and Bloom1 and the correspondence from Mackool.2 It surprised us that Drs. Lee and Bloom overlooked our article, which was published about 2 years before theirs.1 We discussed the use of iris hooks to facilitate phacoemulsification after trauma and suggested that iris hooks could also be useful in any case of lens instability, such as pseudoexfoliation. The technique we described is the same as that discussed by Drs. Lee and Bloom. We agree that the “standard” iris hooks found in operating rooms are adequate to support the lens. Dr. Mackool’s letter also failed to mention our article, although he certainly was aware of the case described in the article. Dr. Mackool was invited to speak at our institution on February 6, 1997. Following his talk on the advantages of the phacoemulsification system that bears his name, the residents and staff presented clinical cases. I presented the history of the patient described in our article and asked for comments before describing our management. Dr. Mackool noted the difficulties of operating on an unstable lens and suggested pars plana phacoemulsification or lensectomy. Another ophthalmologist suggested intracapsular extraction. I then described the use of iris hooks to support the lens during phacoemulsification. In reply, Dr. Mackool mentioned that he had heard the idea at another conference and graciously acknowledged that he had not yet used this technique. He also said that he thought the idea was worth “writing up.” Our manuscript was sent to the journal in September 1996. Iris hooks have been part of the routine equipment of ophthalmic operating rooms for so long that we think
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J CATARACT REFRACT SURG—VOL 26, NOVEMBER 2000
A
© 2000 ASCRS and ESCRS Published by Elsevier Science Inc.
refractive surgery if spectacle and contact lens intolerance develops. Treatment options would be limited to procedures capable of correcting higher amounts of myopia, hyperopia, or astigmatism. While LASIK has shown the most promise of the keratorefractive procedures for higher corrections, the requisite fixation poses centration challenges. Preliminary reports have demonstrated improved BSCVA after PRK in patients as young as 5 years old.5 In that study, the necessary sedation precluded fixation and patient cooperation, so the authors centered the ablation over the pupil with reasonable success. Because PRK may induce more corneal haze in children than in adults, LASIK has demonstrated better predictability and stability than PRK with higher corrections, and the postoperative care for the LASIK patient is considerably easier. Laser in situ keratomileusis will likely prove preferable to PRK in children under 7 years of age. In contrast to keratorefractive techniques, phakic IOLs obviate the need for patient cooperation during the procedure, and the IOLs may correct the more extreme ametropias. Additionally, phakic IOLs are exchangeable in cases of improper power calculations, sizing errors, or untoward refractive changes. Laser in situ keratomileusis or PRK may be performed subsequently should further treatment be desired.6 Because of difficulties in postoperative care in infants and younger children, a foldable phakic IOL that can be implanted through a self-sealing, astigmatically neutral incision would be recommended.2 While major potential complications of phakic IOL surgery include glaucoma, cataract formation, and even endophthalmitis, the risk of not treating a patient with dense anisometropic amblyopia is not only severe but guaranteed.7–9 Functional. Pediatric patients over the age of 7 are not at risk of developing further amblyopia, but these patients may have functional indications for having refractive surgery. Examples include contact-lens-intolerant patients with significant anisometropia, refractive accommodative esotropia, or higher corrections. Photorefractive keratectomy, LASIK, or phakic IOL surgery may enable such patients to participate in certain
LETTERS
recreational or sporting activities, which should positively affect their social development, as occurred in my patient. Elective. Patients capable of wearing contacts or who are obtaining adequate vision with glasses certainly have no medical necessity for refractive surgery. Such patients must be considered the final frontier in pediatric and adolescent refractive surgery. The need is for a procedure that is extremely safe, and the refractive effect should be adjustable, particularly in patients with myopia as myopia tends to progress through adolescence and young adulthood. While LASIK has some adjustable attributes, lifting a corneal flap years after the primary procedure is not always possible, and creating a new flap poses some risk. Additionally, the induced corneal thinning may preclude further enhancement surgery. Intacs may be useful, although its range of correction is quite low and experience with explanting the intracorneal segments after several years is limited. Phakic IOL surgery offers the potential benefits of exchangeability and the ability to perform LASIK for residual refractive errors. Adjustable IOLs may one day allow laser fine-tuning of postoperative refractive errors (R.K. Maloney, MD, J. Jethmalani, MD, C. Sandstadt, MD, et al. “Laser Adjustable IOL,” presented at the annual meeting of the International Society of Refractive Surgery, Orlando, Florida, USA, October 1999). As we gain experience with the obligatory and functional situations, the safety of keratorefractive surgery, the compatibility of phakic IOLs, and the viability and safety of periodic IOL exchanges or LASIK enhancements in pediatric eyes will be determined. After thorough clinical studies of such eyes, we may begin to consider moving into the territory of surgically correcting the more elective types of problems. JONATHAN M. DAVIDORF, MD West Hills, California, USA References 1. Agarwal A, Agarwal A, Agarwal T, et al. Results of pediatric laser in situ keratomileusis. J Cataract Refract Surg 2000; 26:684 – 689 2. Lesueur LC, Arne JL. Phakic posterior chamber lens implantation in children with high myopia. J Cataract Refract Surg 1999; 25:1571–1575 3. Singh D. Photorefractive keratectomy in pediatric patients. J Cataract Refract Surg 1995; 21:630 – 632 4. Nano HD Jr, Muzzin S, Irigaray F. Excimer laser photorefractive keratectomy in pediatric patients. J Cataract Refract Surg 1997; 23:736 –739 1568
5. Alio´ JL, Artola A, Claramonte P, et al. Photorefractive keratectomy for pediatric myopic anisometropia. J Cataract Refract Surg 1998; 24:327–330 6. Zaldivar R, Davidorf JM, Oscherow S, et al. Combined posterior chamber phakic intraocular lens and laser in situ keratomileusis: bioptics for extreme myopia. J Refract Surg 1999; 15:299 –308 7. Zaldivar R, Davidorf JM, Oscherow S. Posterior chamber phakic intraocular lens for myopia of ⫺8 to ⫺19 diopters. J Refract Surg 1998; 14:294 –305 8. Davidorf JM, Zaldivar R, Oscherow S. Posterior chamber phakic intraocular lens for hyperopia of ⫹4 to ⫹11 diopters. J Refract Surg 1998; 14:306 –311 9. Greenwald MJ, Parks MM. Amblyopia. In: Tasman W, Jaeger EA, eds, Duane’s Clinical Ophthalmology, Vol 1. Philadelphia, PA, JB Lippincott Co, 1994; 1–22
Microhooks in Phacoemulsification e have read the article by Lee and Bloom1 and the correspondence from Mackool.2 It surprised us that Drs. Lee and Bloom overlooked our article, which was published about 2 years before theirs.1 We discussed the use of iris hooks to facilitate phacoemulsification after trauma and suggested that iris hooks could also be useful in any case of lens instability, such as pseudoexfoliation. The technique we described is the same as that discussed by Drs. Lee and Bloom. We agree that the “standard” iris hooks found in operating rooms are adequate to support the lens. Dr. Mackool’s letter also failed to mention our article, although he certainly was aware of the case described in the article. Dr. Mackool was invited to speak at our institution on February 6, 1997. Following his talk on the advantages of the phacoemulsification system that bears his name, the residents and staff presented clinical cases. I presented the history of the patient described in our article and asked for comments before describing our management. Dr. Mackool noted the difficulties of operating on an unstable lens and suggested pars plana phacoemulsification or lensectomy. Another ophthalmologist suggested intracapsular extraction. I then described the use of iris hooks to support the lens during phacoemulsification. In reply, Dr. Mackool mentioned that he had heard the idea at another conference and graciously acknowledged that he had not yet used this technique. He also said that he thought the idea was worth “writing up.” Our manuscript was sent to the journal in September 1996. Iris hooks have been part of the routine equipment of ophthalmic operating rooms for so long that we think
W
J CATARACT REFRACT SURG—VOL 26, NOVEMBER 2000