Hyperopia and Presbyopia - part 4 pdf

92 Mian and Azar corneal thickness. Clinical studies have established the safety and efficacy of Ho:YAG LTK up to 2 years after treatment. LTK may also be used to treat PRK and LASIK- induced hyperopia. Diode lasers may help further improve stability of refractive effect with LTK. Wavefront-guided LTK may further improve the predictability of this procedure and allow for predictable outcomes even for retreatments of initial undercorrections. REFERENCES 1. Lans LJ. Experimentelle Untersuchungen u ¨ ber Entstehung von Astigmatismus durch nicht- perforirende Corneawunden. Graefes Arch Ophthalmol 1898; 45:117–152. 2. Terrien F. Dystrophie marginale symme ´ trique des deux cornee ´ s avec astigmatisme regulier consecutif et guerison par la cauterisation ignee. Arch Ophthalmol (Paris) 1900; 20:12–21. 3. Wray C. Case of 6 D of hypermetropic astigmatism cured by the cautery. Trans Ophthalmol Soc UK 1914; 34:109–110. 4. Gassett AR, Shaw EL, Kaufman HE, Itoi M, Sakimoto T, Ishii Y. 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Connect Tissue Res 1980; 7:127–133. 25. Koch DD. Histological changes and wound healing response following noncontact holmium: YAG laser thermal keratoplasty. Tr AM Ophth Soc 1996; 94:745–802. 26. Bakerman S. Distribution of the alpha- and beta-components in human skin collagen with age. Biochim Biophys Acta (Amst) 1964; 90:621. 27. McCally RL, Bargeron CB, Green WR, Farrell RA. Stromal damage in rabbit corneas exposed to CO 2 laser radiation. Exp Eye Res 1983; 37:543–550. 28. Smelser GK, Polack FM, Ozanics V. Persistence of donor collagen in corneal transplants. Exp Eye Res 1965; 4:349–354. 29. Lass JH, Ellison RR, Wong KM, Klein L. Collagen degradation and synthesis in experimental corneal grafts. Exp Eye Res 1986; 42:201–210. 30. Koch DD, Berry MJ, Vassiliadis A. Non-contact holmium:YAG laser thermal keratoplasty. In: Salz JJ, ed. Corneal Laser Surgery. Philadelphia: Mosby-Year Book, 1994:247–254. 31. Alio ´ JL, Pe ´ rez-Santonja JJ. Correction of hyperopia by laser thermokeratoplasty (LTK). In: Agarwal S, Agarwal A, Pallikaris IG, Neuhann TH, Knorz MC, Agarwal A, eds. Refractive Surgery. New Delhi: Jaypee, 2000:583–591. 32. Cavanaugh TB, Durrie DS. Holmium YAG laser thermokeratoplasty: synopsis of clinical experience. Semin Ophthalmol 1994; 9(2):110–116. 33. Koch DD, Kohnen T, McDonnell PJ, Menefee RF, AAS, Berry MJ. Hyperopia correction by noncontact holmium: YAG laser thermal keratoplasty. United States phase IIA clinical study with a 1-year follow-up. Ophthalmology 1996; 103(10):1525–1535. 34. Tutton MK, Cherry PM. Holmium:YAG laser thermokeratoplasty to correct hyperopia: two years follow-up. Ophthalm Surg Lasers 1996; 27(5 suppl):S521–S524. 35. Eggink CA, Bardak Y, Cuypers MHM, Deutman AF. Treatment of hyperopia with contact Ho:YAG laser thermal keratoplasty. J Refract Surg 1999; 15(1):16–22. 36. Lim KH, Kim WJ, Wee WR, Shin DE, Lee JH, Chang BL. Holmium: YAG laser thermokera- toplasty for astigmatism in rabbits. J Refract Surg 1996; 12(1):190–193. 37. Hennekes R. Holmium:YAG laser thermokeratoplasty for correction of astigmatism. J Refract Surg 1995; 11(3 suppl):S358-S360. 38. Thompson V. Holmium: YAG laser thermokeratoplasty for correction of astigmatism. J Refract Corneal Surg 1994; 10:S293. 39. Ariyasu RG, Sand B, Menefee R, AAS, Hennings D, Rose C, Berry M, Garbus JJ, McDonnell PJ. Holmium laser themokeratoplasty of 10 poorly sighted eyes. J Refract Surg 1995; 11: 358–365. 40. Koch DD, Kohnen T, McDonnell PJ, Menefee RF, Berry MJ. Hyperopia correction by noncon- tact holmium:YAG laser thermal keratoplasty. United States phase IIA clinical study with a 1-year follow-up. Ophthalmology 1996; 103(10):1525–1535. 41. Kohnen T, Husain SE, Koch DD. Corneal topographic changes after noncontact holmium:YAG laser thermal keratoplasty to correct hyperopia. J Cataract Refract Surg 1996; 22:427–435. 42. Koch DD, Abarca A, Villarreal R, Menefee R, AAS, Kohnen T, Vassiliadis A, Berry M. Hyperopia correction by noncontact holmium:YAG laser thermal keratoplasty. Clinical study with two-year follow-up. Ophthalmology 1997; 104(11):1938–1947. 43. Kohnen T, Koch DD, McDonnell PJ, Menefee RF, Berry MJ. Noncontact holmium:YAG laser thermal keratoplasty to correct hyperopia: 18-month follow-up. Ophthalmologica 1997; 211: 274–282. 44. Vinciguerra P, Kohnen T, Azzolini M, Radice P, Epstein D, Koch DD. Radial and staggered treatment patterns to correct hyperopia using noncontact holmium:YAG laser thermal kera- toplasty. J Cataract Refract Surg 1998; 24:21–30. 94 Mian and Azar 45. Koch DD, Kohnen T, Anderson JA, Binder PS, Moore MN, Menefee RF, AAS, Valderamma GL, Berry MJ. Histologic changes and wound healing response following 10-pulse noncontact holmium:YAG laser thermal keratoplasty. J Refract Surg 1996; 12:623–634. 46. Kohnen T, Villarreal V, R, Menefee R, Berry M, Koch DD. Hyperopia correction by noncontact holmium:YAG laser thermal keratoplasty: five-pulse treatments with 1 year follow-up. Graefes Arch Clin Exp Ophthalmol 1997; 235:702–708. 47. Alio ´ JL, Ismail MM, Sanchez Pego JL. Correction of hyperopia with non-contact Ho:YAG laser thermal keratoplasty. J Refract Surg 1997; 13(1):17–22. 48. Gezer A. The role of patient’s age in regression of holmium:YAG thermokeratoplasty-induced correction of hyperopia. Eur J Ophthalmol 1997; 7(2):139–143. 49. Nano HD, Muzzin S. Noncontact holmium:YAG laser thermal keratoplasty for hyperopia. J Cataract Refract Surg 1998; 24:751–757. 50. Aker AB, Brown DC. Hyperion laser thermokeratoplasty for hyperopia. Int Ophthalmol Clin 2000; 40(3):165–181. 51. Portellinha W, Nakano K, Oliveira M, Simoceli R. Laser in situ keratomileusis for hyperopia after thermal keratoplasty. J Refract Surg 1999; 15(2 suppl):S218–S220. 52. Attia W, Pe ´ rez-Santonja JJ, Alio ´ JL. Laser in situ keratomileusis for recurrent hyperopia following laser thermal keratoplasty. J Refract Surg 2000; 16:163–169. 53. Pop M. Laser thermal keratoplasty for the treatment of photorefractive keratectomy overcorrec- tions: a 1-year follow-up. Ophthalmology 1998; 105(5):926–931. 54. Alio ´ JL, Ismail MM, Artola A, Pe ´ rez-Santonja JJ. Correction of hyperopia induced by photore- fractive keratectomy using non-contact Ho:YAG laser thermal keratoplasty. J Refract Surg 1997; 13:13–16. 55. Eggink CA, Meurs P, Bardak Y, Deutman AF. Holmium laser thermal keratoplasty for hyper- opia and astigmatism after photorefractive keratectomy. J Refract Surg 2000; 16:317–322. 56. Goggin M, Lavery F. Holmium laser thermokeratoplasty for the reversal of hyperopia after myopic photorefractive keratectomy. Br J Ophthalmol 1997; 81:541–543. 57. Pe ´ rez-Santonja JJ, Bellot J, Claramonte P, Ismail MM, Alio ´ JL. Laser-in-situ keratomileusis to correct high myopia. J Cataract Refract Surg 1997; 23:372–385. 58. Ismail MM, Alio ´ JL, Pe ´ rez-Santonja JJ. Noncontact thermokeratoplasty to correct hyperopia induced by laser-in-situ keratomileusis. J Cataract Refract Surg 1998; 24:1191–1194. 59. Bende T, Jean B, Oltrup T. Laser thermal keratoplasty using a continuous wave diode laser. J Refract Surg 1999; 15:154–158. 60. Brinkmann R, Koop N, Geerling G, Kampmeier J, Borcherding S, Kamm K, Birngruber R. Diode laser thermokeratoplasty: application strategy and dosimetry. J Cataract Refract Surg 1998; 24(9):1195–1207. 61. Koop N, Wirbelauer C, Tu ¨ ngler A, Geerling G, Bastian GO, Brinkmann R. Thermal damage to the corneal endothelium in diode laser thermokeratoplasty. Ophthalmologe 1999; 96(6): 392–397. 62. Wirbelauer C, Koop N, Tu ¨ ngler A, Geerling G, Birngruber R, Laqua H, Brinkmann R. Corneal endothelial cell damage after experimental diode laser thermal keratoplasty. J Refract Surg 2000; 16:323–329. 63. Geerling G, Koop N, Brinkmann R, Tu ¨ ngler A, Cand med.m, Wirbelauer C, Birngruber R, Laqua H. Continuous-wave diode laser thermokeratoplasty: first clinical experience in blind human eyes. J Cataract Refract Surg 1999; 25:32–40. 9 Conductive Keratoplasty for the Correction of Low to Moderate Hyperopia MARGUERITE B. McDONALD Louisiana State University Health Sciences Center, New Orleans, Louisiana, U.S.A. JONATHAN DAVIDORF Davidorf Eye Group, West Hills, and Maloney Vision Institute, Los Angeles, California, U.S.A. ROBERT K. MALONEY Maloney Vision Institute, Los Angeles, California, U.S.A. EDWARD E. MANCHE Stanford University School of Medicine, Palo Alto, California, U.S.A. PETER HERSH Cornea and Laser Vision Center, Teaneck, New Jersey, U.S.A. GEORGE M. SALIB Tulane University School of Medicine, New Orleans, Louisiana, U.S.A. A. HYPEROPIA CORRECTION BY CONDUCTIVE KERATOPLASTY 1. Thermokeratoplasty Procedures Surgical correction of hyperopia has been a greater challenge to ophthalmology than the correction of myopia. Attempts to steepen the central cornea by non-ablative methods, such as thermal keratoplasty, date back to the rabbit studies by Lans in the nineteenth century. During the 1980s, hot-wire thermokeratoplasty, a technique developed in the 95 96 McDonald et al. Soviet Union, was used to produce thermal burns (up to 600ЊC) that penetrated to 95% of corneal depth (1). Studies showed substantial overcorrection followed by marked regres- sion (2–4). Evaluation of the procedure through well-designed clinical trials before adop- tion and dissemination was recommended (5). The failure of high-temperature probes to produce a stable, predictable, and safe hyperopic correction led to the investigation of other modalities of thermal keratoplasty, including contact holmium: YAG laser thermal keratoplasty (Holmium 25, Technomed, Baesweiler, Germany) (6–8), pulsed, noncontact holmium:YAG laser keratoplasty (non- contact LTK, Hyperion System, Sunrise Technologies, Fremont, CA) (9–18), continuous- wave diode laser thermokeratoplasty (DTK, Rodenstock, ProLaser Medical Systems, Inc., Dusseldorf, Germany) (19–20), and radiofrequency-based conductive keratoplasty (CK) (Refractec, Inc., Irvine, CA) (21). These techniques have been more successful than the original hot-needle technique, although regression and induction of astigmatism have con- tinued to be concerns with some techniques. In addition to thermokeratoplasty procedures, ablative methods, such as photorefrac- tive keratectomy (PRK) (22–27) and laser in situ keratomileusis (LASIK) (28–34), have been used to correct hyperopia. Generally, attempted hyperopia corrections with these methods have been higher (Ͼ3.00 D) than the range recommended for CK. 2. Conductive Keratoplasty: The Mechanism The conductive keratoplasty procedure performed with the ViewPoint CK System (Fig. 1) is designed to treat spherical, previously untreated hyperopia of 0.75 to 3.00 D. Treat- ment of astigmatism, presbyopia, and over- or undercorrections following LASIK or other refractive procedures are other potential applications. Conductive keratoplasty delivers low-energy, high-frequency (radiofrequency, 350 kHz) current directly into the corneal stroma by means of a Keratoplast tip inserted into the peripheral cornea at eight or more treatment points (Fig. 2). Collagen within the targeted treatment zone is heated in a gentle, controlled fashion as a result of the natural resistance of stromal tissue to the flow of the current (35). Because resistance to the flow of the Figure 1 The ViewPoint Conductive Keratoplasty (CK) System: console, probe, and specula. 97Conductive Keratoplasty Figure 2 The CK Keratoplast tip shown next to a 7–0 suture. (Courtesy of Refractec, Inc., Irvine, CA.) current increases with increasing dehydration of collagen, the process tends to be self- limiting. A thermal model predicts a cylindrical footprint approximately 150 to 200 ␮m wide by 500 ␮m deep that extends to approximately 80% of the depth of the mid-peripheral cornea at each treated spot (36). Striae form between the treated spots, creating a band of tightening that increases the curvature of the central cornea, thereby decreasing hyper- opia. The Hyperion noncontact LTK technique, on the other hand, applies heat directly to the surface of the cornea, heating tissue in a gradient, and generates a conical footprint (10). B. THE CONDUCTIVE KERATOPLASTY PROCEDURE 1. The Conductive Keratoplasty Device The Viewpoint CK system consists of a radiofrequency energy-generating console, a hand- held, reusable, pen-shaped handpiece attached by a removable cable and connector, a speculum (choice of two, Lancaster or Barraquer) that provides a large surface for an electrical return path, and a pedal that controls release of radiofrequency energy. Attached to the handpiece is the Keratoplast tip, a single-use, disposable, stainless steel penetrating tip, 90 ␮m in diameter and 450 ␮m long, that delivers the current directly to the corneal stroma. At the very distal portion of the tip is a Teflon-coated stainless-steel stop that assures correct depth of penetration. 2. Patient Selection a. Suitable Patients Patients suitable for treatment with the Viewpoint CK System should have 0.75 to 3.00 D of spherical hyperopia and Յ0.75 D of refractive astigmatism. Visual acuity should be correctable to at least 20/40 in both eyes. Hard or rigid gas-permeable lenses should be 98 McDonald et al. discontinued for at least 3 weeks and soft lenses for at least 2 weeks prior to the preoperative evaluation. Wearers of hard contact lenses should have two central keratometry readings and two manifest refractions taken at least 1 week apart. The manifest refraction measure- ments must not differ from the earlier measurements by more than 0.50 D in either merid- ian. Keratometry mires must be regular. b. Unsuitable Patients Patients with a peripheral pachymetry reading at the 6-mm optical zone of less than 560 ␮m are not suitable for treatment with the Viewpoint CK System. Also unsuitable are those who have had strabismus surgery; have anterior segment pathology; have residual, recurrent, active ocular or uncontrolled eyelid disease or any corneal abnormality; or have signs of progressive or unstable hyperopia. Other relative contraindications are a history of herpes zoster keratitis, herpes simplex keratitis, glaucoma, a history of steroid-respon- sive rise in intraocular pressure (IOP), a preoperative IOP Ͼ21 mmHg, or narrow angles. Patients with diabetes, diagnosed autoimmune disease, connective tissue disease, an immu- nocompromised state, current treatment with chronic systemic corticosteroid or other im- munosuppressive therapy that may affect wound healing; a history of keloid formation; intractable keratoconjunctivitis sicca; or pregnancy are also contraindicated to receive the CK treatment. 3. Examinations Preoperative examinations should include a manifest and cycloplegic refraction, an uncor- rected and best spectacle-corrected visual acuity (distance and near), a slit-lamp and fun- doscopic examination, applanation tonometry, central keratometry, ultrasonic pachymetry, and computed corneal topography. 4. Performing the CK Procedure Correct the patient’s full cycloplegic spectacle refraction. Administer one drop of topical anesthetic three times at 5-min intervals and monitor the patient for degree of anesthesia. Do not use pilocarpine. Insert the CK lid speculum to provide corneal exposure and act as an electrical return path. Do not use a lid drape, for it may prevent direct contact of the lid speculum and eyelid, which would disrupt the electrical current return path. Tape the fellow eye closed. Position the operating microscope or slit-lamp biomicroscope over or in front of the eye to be treated. Mark the cornea with the CK marker, and remind the patient to fixate on the light from the microscope. Dampen the CK marker with gentian violet or rose bengal stain. Center the marker’s cross hairs over the center of the pupil and apply light pressure on the marker to make a circular mark with eight intersections on the cornea. If using gentian violet, irrigate with balanced salt solution to remove excess ink. Dry the surface of the cornea thoroughly with a fiber-free sponge to avoid dissipation of applied energy by a wet surface. Set the appropriate treatment parameters on the console according to the nomogram (Table 1). The default setting for treatment is 350 kHz, 60% power (0.6 W) for 0.6 s. Inspect the Keratoplast tip under the microscope to ensure it is not damaged or bent prior to application. When treating 0.75 to 0.875 D of hyperopia (eight spots), treat only at the 7-mm optical zone, beginning treatment at the 12 o’clock position and continuing in the sequence shown in Figure 3. When treating higher levels of hyperopia, follow the nomo- 99Conductive Keratoplasty Table 1 Conductive Keratoplasty Nomogram Diopters to be Number of corrected CK treatment spots ϩ0.75 D to ϩ0.875 D 8 ϩ1.00 D to ϩ1.625 D 16 ϩ1.75 D to ϩ2.25 D 24 ϩ2.375 D to ϩ3.00 D 32 CK—Conductive Keratoplasty gram and application sequence. For example, for treating 1.00 to 1.625 D of hyperopia, apply a total of 16 spots: 8 spots at the 6-mm optical zone and 8 at the 7-mm optical zone. Begin application at each of these optical zones at the 12 o’clock position and continue in sequence until the full circle of spots has been completed. For treating 1.75 to 2.25 D, apply treatment at the 6-, 7-, and 8-mm optical zones for a total of 24 spots. For treating 2.375 D to 3.00 D, apply treatment to the 6-, 7-, and 8-mm optical zones and then to each of the eight sectors between the previously treated spots at the 7-mm optical zone for a total of 32 spots. To treat each spot, place the tip of the delivery probe at the treatment mark on the cornea, perpendicular to the corneal surface. Apply light pressure until the tip penetrates the cornea down to the insulator stop. Depress the foot pedal to apply the radio frequency energy. A tone will sound as the energy is applied. At each treatment spot, keep the tip in place until the preprogrammed treatment time has been completed (the tone stops). Clean the tip with a fiber-free sponge after each treatment spot to remove any tissue debris, Figure 3 Number, location, and sequence of treatment spots. (Courtesy of Refractec, Inc., Irvine, CA.) 100 McDonald et al. taking care not to damage the tip. Perform intraoperative keratometry after completing the full circle of treatments to check for any induced cylinder. 5. Postoperative Care The surgeon may follow his or her usual refractive surgery postoperative care regimen. Administration of one drop of a topical ophthalmic antibiotic solution and one drop of an ophthalmic nonsteroidal anti-inflammatory drug, continued for up to 3 days, according to product labeling, is recommended. Administration of topical corticosteroids is not recom- mended. A bandage contact lens may be used for comfort for 24 to 48 h postoperatively but is usually not necessary. C. UNITED STATES MULTICENTER CLINICAL TRIAL 1. Patients and Methods A 2-year, multicenter, prospective clinical trial is being conducted in the United States to evaluate the safety, efficacy, and stability of conductive keratoplasty when performed on eyes with 0.75 to 3.00 D of hyperopia and less than 0.75 D of cylinder. Each procedure was performed by one of 14 surgeons at 20 centers according to methods described above. All eyes were treated at the default setting of 350 kHz, 60% power for 0.6 s. No retreatments were performed. A total of 231 patients were treated; 361 eyes were treated with the current nomogram for CK and an additional 29 were treated with an earlier nomogram that had a tendency to undercorrect (Table 2). These 29 eyes were excluded from analysis of efficacy variables. Thus, data from 361 eyes were evaluated for efficacy, stability, and safety, while data from 390 eyes were evaluated for stability and safety only. At 12 months, a total of 96 eyes were available for stability and safety analyses and 127 were available for stability, safety, and efficacy analyses. Uncorrected distance visual acuity (UCVA) preoperatively was 20/40 or worse in 81% of the eyes, and uncorrected near visual acuity was J5 or worse in 95%. Postoperative care and examinations followed the methods described above. Table 2 Clinical Study Eyes Eyes Attribute MRSE—Manifest refractive spherical equivalent CRSE—Cycloplegic refractive spherical equivalent Evaluated for safety and stability variables only Evaluated for all variables (Efficacy, safety, stability) Available at 12 months for stability and safety analyses Available at 12 months for safety, efficacy, and stability analyses Age Mean Preoperative MRSE Mean Preoperative CRSE N ϭ 390 N ϭ 361 N ϭ 96 N ϭ 127 55 Ϯ 5.4 years (40 to 74) ϩ1.82 Ϯ 0.60 D (0.75 to 3.00 D) ϩ1.76 Ϯ 0.60 D (0.75 to 3.25 D) 101Conductive Keratoplasty Figure 4 Postoperative UCVA over time. 2. Results a. Efficacy Twelve months postoperatively, UCVA was 20/20 or better in 53/96 (55%), 20/25 or better in 73/96 (76%), and 20/40 or better in 87/96 (91%) of the eyes (Fig. 4). Near UCVA increased an average of six Jaeger lines. Mean MRSE values showed 53/96 (55%) within ע0.50 D of intended correction, 87/96 (91%) within ע1.00 D, and 94/96 (98%) within ע2.00 D (Fig. 5). A summary of the efficacy results with conductive keratoplasty is shown in Table 3. Table 3 Summary of Efficacy Results with Conductive Keratoplasty Compared with FDA Guidelines for Refractive Procedures FDA 6 Months 9 Months 12 Months guideline (Nϭ348) (Nϭ276) (Nϭ96) UCVA Ն 20/20 50% 46% 48% 55% UCVA Ն 20/25 Not stipulated 65% 72% 76% UCVA Ն 20/40 85% 90% 92% 91% MRSE Ϯ 0.50 D 50% 60% 66% 55% MRSE Ϯ 1.00 D 75% 88% 88% 91% MRSE Ϯ 2.00 D Not stipulated 99% 99% 98% FDA ϭ Food and Drug Administration UCVA ϭ Uncorrected Visual Acuity MRSE ϭ Manifest Refractive Spherical Equivalent [...]... keratomileusis for hyperopia J Cataract Refract Surg 1998; 24: 1050–1058 30 Ditzen K, Huschka H, Pieger S Laser in situ keratomileusis for hyperopia J Cataract Refract Surg 1998; 24: 42 47 31 Esquenazi S, Mendoza A Two-year follow-up of laser in situ keratomileusis for hyperopia J Refract Surg 1999; 15: 648 –652 32 Goker S, Er H, Kahvecioglu C Laser in situ keratomileusis to correct hyperopia from ‫52 .4 ‬ to 8.0... ed Surgery for Hyperopia and Presbyopia Williams & Wilkins; 1997:163–171 22 Jackson WB, Mintsioulis G, Agapitos PJ, Casson EJ Excimer laser photorefractive keratectomy for low hyperopia: safety and efficacy J Cataract Refract Surg 1997; 23 :48 0 48 7 23 Daya SM, Tappouni FR, Habib NE Photorefractive keratectomy for hyperopia Six month results in 45 eyes Ophthalmology 1997; 1 04: 1952–1958 24 Vinciguerra... Cornea, 2nd ed Boston: Butterworth-Heinemann, 1997: 1037–1 044 4 Gomez L, Chayet A Laser in situ Keratomileusis results after intrastromal corneal ring segments (intacs) 2001; 108:1738–1 743 5 Anschutz T Laser correction of hyperopia and presbyopia Int Ophthalmol Clin 19 94; 34: 107–137 6 Jackson WB, Casson E, Hodge WG, Mintsioulis G, Agapitos PJ Laser vision correction for low hyperopia Ophthalmology 1998;... 83% of the eyes between the 9- and 12-month visits and in 83% of the eyes between the 9- and 1 2- month visits (Fig 7) The refraction appeared to stabilize at approximately 6 months Figure 7 Change in MRSE between postoperative visits N ‫( 511 ס‬patients present for all followup visits) 1 04 McDonald et al Figure 8 Slit-lamp view of treatment spot 1 h after CK showing bands of striae between spots The... and more than ‫ 0.21ם‬D (group 3) In all groups, the standard deviation between intended and final postoperative uncorrected visual acuities was less than 2.80 D The refractive results were stable at a follow-up of 4 months, and there was no loss of the mean best corrected postoperative best-corrected visual acuity (BCVA) We implanted nine hyperopic patients, ‫ 4. 4ם‬to ‫ 1.8ם‬D, with a mean follow-up... surgeries, and there were no treatment-related adverse events D CONCLUSION The 12-month results in the ongoing 2-year prospective clinical study of the CK technique for correcting low to moderate spherical hyperopia are encouraging Postoperative visual acuity and predictability of refraction were excellent and are comparable to or better than results obtained with PRK or LASIK for low hyperopia (17– 34) The... keratoplasty for hyperopia J Cataract Refract Surg 1998; 24: 751–757 106 McDonald et al 14 Koch DD, Kohnen T, McDonnell PJ, Menefee R, Berry M Hyperopia correction by noncontact holmium:YAG laser thermal keratoplasty: United States phase IIA clinical study with a 2year follow-up Ophthalmology 1997; 1 04: 1938–1 947 15 Alio JL, Ismail MM, Sanchez Pego JL Correction of hyperopia with non-contact Ho:YAG laser... 1995: 247 –2 54 8 McCarey B, Andrews D Refractive keratoplasty with intrastromal hydrogel lenticular implants Invest Ophthalmol Vis Sci 1981; 21:107–115 9 Gomez ML, Barraquer JI Permalens hydrogel intracorneal lenses for spherical ametropia J Refract Surg 1997; 13: 342 – 348 10 Reinstein DZ, Srivannaboon S, Holland SP Epithelial and stromal changes induced by Intacs examined by three-dimensional very high-frequency... Hyperopia correction by noncontact holmium: YAG laser thermal keratoplasty: US phase IIA clinical study with 2-year followup Ophthalmology 1997; 1 04( suppl 11):1938–1 947 13 Brinkmann R, Radt B, Flamm C, Kampmeier J, Koop N, Birngruber R Influence of temperature and time on thermally induced forces in corneal collagen and the effect on laser thermokeratoplasty J Cataract Refract Surg 1995; 26: 744 –7 54. .. the study (Table 4) During the last two intervals (6 to 9 months, 9 to 12 months), the mean MRSE changed 0.09 D (confidence interval 0.01, 0.17) and 0.16 D (confidence intervals 0.07 and 0.22), respectively The mean change in MRSE between postoperative visits from 0.50 D or less in 73% of the eyes between the 3- and 6-month visits, in 85% of the eyes between the 6and 9-month visits, and in 83% of the . between the 3- and 6-month visits, in 85% of the eyes between the 6- and 9-month visits, and in 83% of the eyes between the 9- and 12-month visits and in 83% of the eyes between the 9- and 1 2- month. examinations should include a manifest and cycloplegic refraction, an uncor- rected and best spectacle-corrected visual acuity (distance and near), a slit-lamp and fun- doscopic examination, applanation. Non-contact holmium:YAG laser thermal keratoplasty. In: Salz JJ, ed. Corneal Laser Surgery. Philadelphia: Mosby-Year Book, 19 94: 247 –2 54. 31. Alio ´ JL, Pe ´ rez-Santonja JJ. Correction of hyperopia