Effect of varying the optical zone diameter on the results of hyperopic laser in situ keratomileusis.

PURPOSE: To compare the predictability and safety of laser in situ keratomileusis (LASIK) for low to moderate spherical hyperopia using different ablation zone diameters. DESIGN: Retrospective, nonrandomized, comparative trial. PARTICIPANTS: Forty-nine eyes that underwent hyperopic LASIK. INTERVENTION: Two surgeons (JMD, RKM) performed hyperopic LASIK using the VISX STAR S2 excimer laser (VISX, Inc., Sunnyvale, CA) and the Bausch & Lomb Hansatome microkeratome (Chiron Vision, Irvine, CA) using ablation zone diameters of 5 x 9 mm, 5.5 x 8.5 mm, or 6 x 9 mm (the first number represents the optical zone diameter and the second number represents the diameter of the outer border of the ablation zone). MAIN OUTCOME MEASURES: Refractive and visual outcomes at 3 to 6 months after surgery were analyzed. Groups were compared for deviations from targeted spherical equivalent, uncorrected visual acuity, and loss of best spectacle-corrected visual acuity (BSCVA). RESULTS: The mean intended hyperopic correction was +2.48 +/- 1.13 diopters (D; 0.63-5.50 D). There were 16 eyes in the 5 x 9-mm group, 15 eyes in the 5.5 x 8.5-mm group, and 18 eyes in the 6 x 9-mm group. On average, the 5 x 9-mm group achieved 97% of the programmed correction, the 5.5 x 8.5-mm group achieved 104%, and the 6 x 9-mm group achieved 112% of the programmed correction. The tendency toward overcorrection in the 6 x 9-mm group compared with the 5 x 9-mm group was statistically significant (P < 0.05). The incidence of one line loss of BSCVA was greatest in the 5 x 9-mm group (19%) and lowest in the 6 x 9-mm group (6%). These differences were not statistically significant. No eyes experienced a loss of two or more lines of BSCVA at last examination. CONCLUSIONS: Hyperopic LASIK using the VISX STAR is safe and effective using different ablation zone diameters. There appears to be an increased tendency toward overcorrection with progressively larger optical zone diameters.

Conductive keratoplasty for the correction of hyperopia.

BACKGROUND/PURPOSE: Conductive keratoplasty (CK) is a surgical technique that delivers radio frequency (350 kHz) current directly into the corneal stroma through a Keratoplasty tip inserted into the peripheral cornea at 8 to 32 treatment points. A full circle of CK spots produces a cinching effect that increases the curvature of the central cornea, thereby decreasing hyperopia. We report here the 12-month results of a 2-year, prospective, multicenter US clinical trial conducted to evaluate the efficacy, safety, and stability of CK. METHODS: A total of 233 patients (401 eyes) with preoperative hyperopia of +0.75 to +3.00 D and < or = 0.75 D of astigmatism (mean preoperative manifest refractive spherical equivalent = +1.76 D +/- 0.60) were enrolled into the study at 13 centers and underwent CK treatment. RESULTS: Twelve-month postoperative data are available on 203 eyes for safety and stability and 171 eyes for safety, stability, and efficacy. A total of 91% had uncorrected visual acuity (UCVA) of 20/40 or better, and 51% had UCVA of 20/20 or better. Manifest refractive spherical equivalent was within +/- 0.50 D in 58%, within +/- 1.00 D in 91%, and within +/- 2.00 D in 99%. The mean change in residual refraction was 0.26 D +/- 0.49 between 3 and 6 months, 0.09 D +/- 0.37 between 6 and 9 months, and 0.13 D +/- 0.39 between 9 and 12 months. CONCLUSIONS: One-year data show safety and efficacy of CK in the treatment of hyperopia. Changes in residual refractive error after CK appeared to be small, suggesting that a stable refraction could be achieved by 6 months.

Intraocular lens power calculations in patients with extreme myopia.

PURPOSE: To determine the variables that might contribute to improved intraocular lens (IOL) power calculations preoperatively in cataract patients with extreme myopia. METHODS: This retrospective study included 50 patients with extreme myopia and axial lengths longer than 27.0 mm. All patients had clear corneal phacoemulsification by the same surgeon and implantation of the Domilens SiFlex 1 IOL (power range -6.0 to +5.0 diopters [D]). The performances of the SRK/T, Hoffer Q, Holladay 1, and Holladay 2 formulas in predicting an IOL power that would meet the target refraction of +/-1.00 D were compared. RESULTS: The formulas tended to suggest underpowered IOLs, more severe in eyes with axial lengths greater than 30.00 mm. These eyes accounted for most of the minus-power IOLs implanted. Back calculations of axial lengths in patients with minus-power IOLs showed that, on average, emmetropia could have been predicted by choosing shorter axial lengths (up to 2.72 mm shorter) than those used in the original IOL power calculations. Preoperative B-scan ultrasonography demonstrated the presence of a posterior pole staphyloma temporal to the optic nerve in several patients who required minus-power IOLs, which suggests that axial length measurement problems were a major source of IOL calculation errors in these patients. CONCLUSIONS: In eyes with axial lengths longer than or equal to 27.0 mm, current third- and fourth-generation lens calculation formulas have a tendency to over minus patients between -1.0 and -4.0 D. The formulas appear to perform better for plus-power IOL implantation than for minus-power IOL implantation. The use of B-scan ultrasonography to locate posterior pole staphylomas may improve the accuracy of IOL calculations in eyes with extreme myopia.

Combined posterior chamber phakic intraocular lens and laser in situ keratomileusis: bioptics for extreme myopia.

PURPOSE: To examine the efficacy, predictability, stability, and safety of combined posterior chamber phakic intraocular lens (IOL) implantation and laser in situ keratomileusis (LASIK) in eyes with extreme myopia. METHODS: We analyzed the results of 67 eyes that received a posterior chamber hydrogel-collagen plate phakic IOL (STAAR Collamer Implantable Contact Lens) and also underwent secondary LASIK for the correction of extreme myopia. Mean follow-up was 3 months after the LASIK portion of the procedure (range, 1 day to 6 mo after LASIK). RESULTS: Mean preoperative spherical equivalent refraction was -23.00 +/- 3.60 D (range, -18.75 to -35.00 D), and mean refractive cylinder was 1.50 +/- 1.20 D (range, 0 to 5.00 D). Mean spherical equivalent refraction after IOL implantation and before LASIK was -6.00 +/- 2.80 D (range, -2.00 to -14.38 D) and mean refractive cylinder 1.50 +/- 1.10 D (range, 0 to 5.00 D). Mean postoperative spherical equivalent refraction at last examination after the LASIK portion of the two-part phakic IOL-LASIK procedure was -0.20 +/- 0.90 D (range, +1.75 to -5.13 D), and mean refractive cylinder was 0.50 +/- 0.50 (range, 0 to 2.25 D). Eighty-five percent (57 eyes) were within +/- 1.00 D and 67% (45 eyes) were within +/- 0.50 D of emmetropia at last examination. The refractions remained stable with a statistically insignificant change (P > .05 at each interval) during follow-up. Postoperative uncorrected visual acuity at last examination was 20/20 or better in 3% (2 eyes) and 20/40 or better in 69% (46 eyes). A gain of 2 or more lines of spectacle-corrected visual acuity was seen in 51 eyes (76%) and no eyes lost 2 or more lines of spectacle-corrected visual acuity at last examination. CONCLUSION: Combined posterior chamber phakic IOL implantation with the STAAR Collamer plate lens and LASIK (bioptics) is an effective and reasonably predictable method for correcting myopia from -18 to -35 D. Gains in spectacle-corrected visual acuity were common, and results demonstrated good short-term safety and refractive stability.

Posterior chamber phakic intraocular lens for myopia of -8 to -19 diopters.

PURPOSE: To examine the efficacy, predictability, stability, and safety of posterior chamber phakic intraocular lens (IOL) implantation in patients with extreme myopia. METHODS: We analyzed the results of 124 eyes that received a posterior chamber hydrogel collagen plate phakic IOL (Staar Collamer Implantable Contact Lens, ICL) for the correction of their myopia. The target postoperative spherical equivalent refraction was emmetropia. Mean follow-up was 11 months (range 1 to 36 mo). RESULTS: The mean preoperative spherical equivalent refraction was -13.38 +/- 2.23 D (range, -8.50 to -18.63 D). Mean postoperative spherical equivalent refraction at last examination was -0.78 +/- 0.87 D (range, +1.63 to -3.50 D), with 69% (86 eyes) within +/-1.00 D and 44% (55 eyes) within +/-0.50 D of emmetropia. The refraction remained stable with a statistically insignificant change (p > 0.05 at each interval) during follow-up. A gain of two or more lines of spectacle-corrected visual acuity was seen in 36% (45 eyes) at last examination. One eye (0.8%) lost two or more lines of spectacle-corrected visual acuity from a retinal detachment. CONCLUSION: Posterior chamber phakic IOL implantation with the Staar Collamer plate lens is an effective and safe method for reducing or correcting myopia between -8 and -19 D. Gains in spectacle-corrected visual acuity were common, and results suggested good refractive stability. Improvements in phakic IOL power calculation formulas are needed to improve the predictability of refractive outcome.

Posterior chamber phakic intraocular lens for hyperopia of +4 to +11 diopters.

PURPOSE: To examine the efficacy, predictability, stability, and safety of posterior chamber phakic intraocular lens (IOL) implantation in eyes with high hyperopia. METHODS: We analyzed the results of 24 eyes that received a posterior chamber hydrogel-collagen plate phakic IOL (Staar Collamer Implantable Contact Lens, ICL) for the correction of hyperopia with the goal of emmetropia. Mean follow-up was 8.4 months (range, 1 to 18 mo). RESULTS: The mean preoperative spherical equivalent refraction was +6.51 +/- 2.08 D (range, +3.75 to +10.50 D). Mean postoperative spherical equivalent refraction at last examination was -0.39 +/- 1.29 D (range, +1.25 to -3.88 D), with 79% (19 eyes) within +/-1.00 D and 58% (14 eyes) within +/-0.50 D of emmetropia. Postoperative uncorrected visual acuity at last examination was 20/20 or better in 8% (two eyes) and 20/40 or better in 63% (15 eyes). A gain of two or more lines of spectacle-corrected visual acuity was seen in two eyes (8%) at last examination. One eye (4%) lost two or more lines of spectacle-corrected visual acuity due to progressive neovascular glaucoma initiated by early postoperative pupillary block. CONCLUSION: Posterior chamber phakic IOL implantation with the Staar Collamer plate lens is an effective method for correcting high hyperopia. Large, patent iridotomies are important in hyperopic eyes to lower the risk of postoperative pupillary block. Improved phakic IOL power calculation formulas will refine predictability of refractive outcome.

Results and complications of laser in situ keratomileusis by experienced surgeons.

PURPOSE: To identify intraoperative and early postoperative adverse events and complications that may be encountered after the laser in-situ keratomileusis (LASIK) learning process. METHODS: One hundred sixty-nine consecutive eyes of 108 patients who had LASIK by a surgeon experienced in LASIK were studied. All intraoperative and early postoperative adverse events and complications were noted. Patients were examined at 1 day and 1 to 3 months after surgery. Six baseline refractive groups were studied: high myopia with astigmatism (-10.25 to -17.50 D; 18 eyes), moderate myopia with astigmatism (-6.00 to -9.50 D; 31 eyes), low myopia with astigmatism (-0.75 to -5.87 D; 81 eyes), mixed astigmatism (-0.25 to +0.50 D; 6 eyes), low to moderate hyperopia with astigmatism (+1.00 to +3.75 D; 19 eyes), and high hyperopia with astigmatism (+4.25 to +7.37 D; 12 eyes). Seventy-eight percent (132 eyes) had a primary LASIK procedure; 22% (37 eyes) had LASIK after previous refractive surgery. Primary and secondary LASIK procedures were analyzed together. The Nidek EC-5000 or the Chiron PlanoScan excimer lasers were used. RESULTS: The most commonly observed adverse intraoperative events were minor corneal bleeding (3%) and thin flap (1%). The most commonly observed postoperative events were punctate epithelial keratopathy (6%) and small epithelial defect 1 day after surgery (5%). The most serious complication occurred in three eyes with preoperative high hyperopia (spherical equivalent refraction greater than +4.00 D) in which corneal topographic abnormalities resulted. At last examination, mean postoperative spherical equivalent refraction was less than +1.00 D in all groups. Spectacle-corrected visual acuity was 20/20 in 70 eyes (41%) and 20/25 or better in 119 eyes (70%). Loss of spectacle-corrected visual acuity of two or more lines occurred in five eyes (3%), three of which had preoperative high hyperopia with abnormal postoperative corneal topography. CONCLUSION: Our prospective study should help LASIK surgeons gauge their expectations of intraoperative and early postoperative complications. Surgeons should proceed cautiously when treating patients with high hyperopia, because a higher incidence of loss of spectacle-corrected visual acuity may be encountered postoperatively.

Laser in situ keratomileusis for myopia from -5.50 to -11.50 diopters with astigmatism.

PURPOSE: To determine the efficacy, predictability, safety, and short-term stability of laser in situ keratomileusis (LASIK) in treating patients with high myopia and astigmatism. METHODS: We retrospectively studied the results of our initial 119 eyes with myopia ranging from -5.50 to -11.50 D and astigmatism less than 4.00 D that underwent LASIK with the Nidek EC-5000 excimer laser. Follow-up was at 1 day, 1 month, and 3 to 6 months; follow-up was 71% (84 eyes) at the 3 to 6 month visit (average 4.5 months). RESULTS: Of the 84 eyes with 3 to 6 months of follow-up, mean baseline spherical equivalent refraction was -8.62 +/- 1.27 D and mean cylinder was -1.84 +/- 1.02 D. Mean postoperative spherical equivalent refraction at the last examination was -0.61 +/- 0.84 D and mean cylinder was -0.39 +/- 0.38 D, with 83% (70 eyes) achieving a spherical equivalent refraction within +/-1.00 D of emmetropia, and 56% (47 eyes) within +/-0.50 D. Mean regression of spherical equivalent from 1 day to 1 month was less than -0.50 D and refractions were stable between 1 month and 3 to 6 months. An uncorrected visual acuity of 20/40 or better was noted in 84% (71 eyes) of these eyes on day 1 after surgery, in 75% (63 eyes) at 1 month, and in 77% (65 eyes) at 3 to 6 months. Twenty-two percent (18 eyes) of these eyes achieved 20/20 or better uncorrected visual acuity at 3 to 6 months; only 17% (14 eyes) had 20/20 or better spectacle-corrected visual acuity before surgery. One patient lost two or more lines of spectacle-corrected visual acuity at the last examination due to epidemic keratoconjunctivitis. CONCLUSION: LASIK with the Nidek EC-5000 excimer laser appears to be an effective and safe means for treating patients with high myopia and astigmatism. Studies with longer follow-up will help evaluate the long-term stability of the procedure and the possibility of late complications.

Laser in situ keratomileusis for low myopia and astigmatism with a scanning spot excimer laser.

PURPOSE: To determine the efficacy, predictability, safety, and short term stability of laser in situ keratomileusis (LASIK) in treating patients with low myopia and astigmatism using the Chiron Technolas Keracor 117 PlanoScan excimer laser. METHODS: We retrospectively studied the results of our initial 83 eyes with myopia ranging from -1.13 to -7.25 diopters (D) and astigmatism of no more than 4.00 D that underwent LASIK with the Chiron Technolas Keracor 117 PlanoScan. Follow-up was at 1 day, 1 month, and 3 to 6 months. RESULTS: Mean baseline spherical equivalent refraction was -3.54 +/- 1.41 D and cylinder -1.64 +/- 1.14 D. Mean postoperative spherical equivalent refraction was -0.52 +/- 0.50 D at 1 month and -0.65 +/- 0.62 D at 3 to 6 months; mean postoperative refractive cylinder was -0.45 +/- 0.54 D at 1 month and -0.50 +/- 0.63 D at 3 to 6 months. Fifty-three percent (44 eyes) achieved a spherical equivalent refraction within +/- 0.50 D and 81% (67 eyes) within +/- 1.00 D of emmetropia at the last examination. Fifty-seven percent (47 eyes) achieved a refractive cylinder of < or = 0.50 D, and 27% (22 eyes) had an undercorrection of their refractive cylinder at the last examination. An uncorrected visual acuity of 20/40 or better was achieved in 86% (71 eyes) of patients on postoperative day one, in 81% (67 eyes) at 1 month, and in 76% (63 eyes) at 3 to 6 months. Twenty-eight percent (23 eyes) saw 20/20 or better uncorrected at the last visit (41% [34 eyes] had a baseline spectacle-corrected visual acuity of 20/20). There was no statistically significant difference in the refractions or uncorrected visual acuities between the different postoperative examinations. No eye experienced a loss of spectacle-corrected visual acuity of more than one line at the last examination. CONCLUSION: LASIK with the Chiron PlanoScan excimer laser appears to be an effective, safe, and reasonably predictable means to reduce low myopia and astigmatism. Adjustment of computer algorithms is needed to decrease the number of under-corrections.

Treatment of the fellow eye in acute angle-closure glaucoma: a case report and survey of members of the American Glaucoma Society.

PURPOSE: A survey of members of the American Glaucoma Society was compiled to determine the treatment practices of subspecialty-trained glaucoma specialists regarding the treatment of the fellow eye in acute angle-closure glaucoma. METHODS: We surveyed 200 members of the American Glaucoma Society regarding treatment options for the fellow eye of a patient with acute angle-closure glaucoma. The survey was mailed and was preceded by a case of a patient who had acute angle-closure glaucoma and in whom definitive prophylactic laser iridotomy was temporarily deferred; her eye developed acute angle-closure glaucoma despite treatment with pilocarpine. RESULTS: One hundred fifty-five of the 200 mailed surveys were answered and returned. Pilocarpine alone was the most common response category (50.3% of respondents), followed by observe/close follow-up (32.9%). Other response categories were selected by < 5% of the respondents. CONCLUSION: Pilocarpine is well supported by the literature and by subspecialty-trained glaucoma specialists as the treatment of the fellow eye in cases of acute angle-closure glaucoma when laser iridotomy is temporarily deferred. The present case reminds us that the fellow eye is highly susceptible to acute angle closure glaucoma and that prophylactic laser iridotomy should be performed at the earliest possible juncture.

Distal cervical spine evaluation using swimmer's flexion-extension radiographs.

Radiographic evaluation of the cervical spine begins with anteroposterior, lateral, and odontoid views. Unless the junction of C7-T1 can be adequately visualized on the cross-table lateral view, a swimmer's view is often performed. After fractures and subluxations have been excluded with these nonstressed views, spinal stability may be evaluated with stressed view radiographs such as a flexion-extension series. However, there is currently no protocol for evaluating the distal spinal stability in patients in whom traditional flexion-extension radiographs fail to visualize the important distal C7-T1 juncture. The present case study describes a trauma patient suffering from neck pain in whom cervical spine instability was ruled out using a swimmer's flexion-extension technique. Further study of this technique as a supplement to the conventional flexion and extension views in the stressed assessment of the entire cervical spine is recommended.

Treatment of iris melanoma with photodynamic therapy.

Photodynamic therapy was used to treat four patients with iris melanoma. Hematoporphyrin derivative was used as a sensitizing agent. The tumors were exposed to a total dose of 1.72 x 10(6) J/cm2 of 630-nanometer laser light. The eye of the first patient, enucleated after treatment, histopathologically showed significant tumor necrosis. The tumors in the three subsequent patients were almost completely ablated, with no evidence of regrowth.