LASIK correction of spherical hyperopia, hyperopic astigmatism, and mixed astigmatism with the LADARVision excimer laser system

LASIK Correction of Spherical Hyperopia, Hyperopic Astigmatism, and Mixed Astigmatism with the LADARVision Excimer Laser System James J. Salz, MD,1 Christy A. Stevens, OD,2 for the LADARVision LASIK Hyperopia Study Group Objective: To assess the safety and effectiveness of the LADARVision active tracking narrow beam excimer laser system (Alcon Surgical, Orlando, FL) using laser in situ keratomileusis (LASIK) for correction of spherical hyperopia, hyperopic astigmatism, and mixed astigmatism. Design: A multicenter, prospective non-randomized (self-controlled) comparative trial. Participants: A total of 360 eyes, including 152 spherical hyperopic, 143 hyperopic astigmatic, and 65 mixed astigmatic, were treated for up to ⫹6.00-diopter (D) sphere with up to ⫺6.00-D cylinder. Intervention: Treatments were performed at six sites in the United States using a 6-mm optic zone with a 1.5-mm peripheral blend zone for a maximum ablation zone diameter of 9 mm. Main Outcome Measures: Uncorrected visual acuity (UCVA), manifest refraction, vector analysis, best spectacle-corrected visual acuity (BSCVA), complications and adverse reactions, subjective symptoms, and patient satisfaction. Results: Six and 12 months of follow-up, respectively, were available on 143 and 117 spherical hyperopic eyes, 124 and 74 hyperopic astigmatic eyes, and 57 and 38 mixed astigmatic eyes, respectively. For spherical hyperopes at 6 and 12 months, UCVA was 20/40 or better in 93.4% and 93.9% of eyes, respectively. The manifest refraction spherical equivalent (MRSE) was within 0.50 D of intended in 65.0% and 74.1% of eyes, respectively, and within 1.00 D in 87.4% and 91.4%, respectively. Refractive stability was demonstrated in 94.2% or more of eyes between the intervals of 1 to 3 months and 3 to 6 months and in 95.3% or more of eyes to 12 months. A loss of two lines of BSCVA occurred in 3.5% and 3.4%, respectively, and no eyes lost more than two lines. For hyperopic astigmats at 6 and 12 months, UCVA was 20/40 or better in 90.9% and 93.8% of eyes, respectively. The MRSE was within 0.50 D of intended in 60.5% and 73.0% of eyes, respectively, and within 1.00 D in 88.7% and 89.2% of eyes, respectively. Refractive stability was demonstrated in 96.5% or more of eyes, respectively, between the intervals of 1 to 3 months and 3 to 6 months and 95.5% or more to 12 months. A loss of two lines of BSCVA occurred in 5.8% and 1.4% of eyes, respectively, and no eyes lost more than two lines. For mixed astigmats at 6 and 12 months, UCVA was 20/40 or better in 92.6% and 94.4% of eyes, respectively. The MRSE was within 0.50 D of intended in 64.9% and 73.7% of eyes, respectively, and within 1.00 D in 87.7% and 94.7% of eyes, respectively. Refractive stability was demonstrated in 100% of eyes between the intervals of 1 to 3 months and 3 to 6 months and in 97.0% or more to 12 months. A loss of two lines of BSCVA occurred in 1.9% and 0.0% of eyes, respectively, and no eyes lost more than two lines. Conclusions: The data support safety and effectiveness of the LASIK correction of spherical hyperopia, hyperopic astigmatism, and mixed astigmatism with the LADARVision system. Ophthalmology 2002;109: 1647–1657 © 2002 by the American Academy of Ophthalmology. The LADARVision excimer laser system (Alcon Surgical, Orlando, FL) features a laser with a beam diameter of less Originally received: October 22, 2000. Accepted: October 25, 2001. Manuscript no. 200606. 1 American Eye Institute, Los Angeles, California. 2 Alcon Surgical, Orlando, Florida. Presented in part at the American Academy of Ophthalmology annual meeting, Dallas, Texas, October 2000. Supported by Alcon Surgical, Orlando, Florida. Christy Stevens is an employee of Alcon Surgical. The other authors have no proprietary interest in the LADARVision system or Alcon Surgical. © 2002 by the American Academy of Ophthalmology Published by Elsevier Science Inc.

than 1 mm and a wavelength of 193 nm. Accurate placement of the narrow laser beam is ensured using an active eye tracking system, which transmits a signal to the eye 4000 times per second to determine eye position in real time. The infrared active eye tracking system compensates for rapid eye movements, including drifts and saccades, while the laser ablation continues. This combination of the Dr. Salz is a paid consultant to Alcon Surgical. Reprint requests to Christy Stevens, OD, Alcon Surgical, 2501 Discovery Drive, Suite 500, Orlando, FL 32826. E-mail: christy.stevens@ alconlabs.com. ISSN 0161-6420/02/$–see front matter PII S0161-6420(02)01133-8

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Ophthalmology Volume 109, Number 9, September 2002 narrow laser beam and the active eye tracking provides the ability to ablate complex shapes accurately and to customized profiles. The algorithm for the correction of hyperopia, hyperopic astigmatism, and mixed astigmatism, displayed in Figure 1, is designed to remove the minimal amount of corneal tissue and create a smooth ablation over a 9-mm zone. Safety and effectiveness of the LADARVision excimer laser system for the correction of myopia and astigmatism with photorefractive keratectomy and laser in situ keratomileusis (LASIK) have been demonstrated previously in clinical trials.1,2 The data to follow represent the first eyes treated for LASIK correction of hyperopia, hyperopic astigmatism, and mixed astigmatism using this technology and were collected in a multicenter, prospective study to determine the safety and effectiveness of the LADARVision system.

Patients and Methods This study of the LADARVision excimer laser system was conducted under an Investigational Device Exemption (IDE) and in accordance with United States Food and Drug Administration regulations. Prospective enrollment of patients in this cohort occurred consecutively between August 10, 1998, and June 4, 1999, at six clinical sites in the United States. Fourteen investigators performed LASIK correction of up to ⫹6-diopters (D) sphere and up to ⫺6 D astigmatism on 360 eyes, including 152 spherical hyperopic corrections, 143 hyperopic astigmatic corrections, and 65 mixed astigmatic corrections. Treatment was based on the preoperative cycloplegic refraction in minus cylinder form as shown in Table 1. For eyes with 0.50 to 0.75 D of astigmatism, the surgeon had the option of treating the spherical equivalent or treating the astigmatism. Eyes with at least 1.00 D of astigmatism were treated for astigmatism. Patients were given the option of having an intentional overcorrection in one eye if a monovision outcome was desired. A monovision target of ⫺1.00 to ⫺2.50 D was intended in 45 eyes (12.5%) and emmetropia was targeted in 315 eyes (87.5%). A nomogram adjustment of adding ⫹1.00 D to the preoperative cycloplegic sphere was used for all eyes, based on an initial analysis of eyes treated in a prior study on photorefractive keratectomy hyperopia with astigmatism. The protocol and informed consent were reviewed and approved by an investigational review board for each institution. The procedures, risks, and benefits of the LASIK surgery were explained to all patients before they signed the informed consent. Before enrollment, all patients were evaluated to determine eligi-

bility based on the protocol. Study inclusion criteria included: a minimum age of 18 years, a visual acuity correctable to 20/40 or better, and no history of previous corneal or intraocular surgery. Patients who had a history of eye disease, such as glaucoma or herpes keratitis, or presence of active ocular disease, were excluded from the study. However, patients with nonvisually and nonclinically significant lens changes were allowed in the study. These lens changes were not an unexpected finding, given the average patient age in the hyperopic population seeking LASIK correction. Eyes with irregular corneal astigmatism or signs of keratoconus were excluded based on assessment of topography or irregular corneal mires on keratometry. Other exclusion criteria included medical conditions affecting healing, use of systemic medications with significant ocular side effects, and pregnancy or lactation. Stability of refraction for the previous 12 months must have been established, and the preoperative manifest and cycloplegic refractions must have been within 1.00 D of each other. The mean patient age for the entire cohort was 53 ⫾ 9.9 years, with a range from 21 to 74 years. Approximately 70% of patients enrolled were 50 years of age or older, as displayed in Figure 2. Most patients (98.6%) were white. The male-to-female distribution was approximately equal for the entire cohort. However, the mixed astigmatism subset of patients had a gender distribution of 75% males to 25% females. In the overall population, 53% of patients had no history of contact lens wear, 41% wore soft contact lenses, and 6% wore rigid gas permeable (RGP) or polymethylmethacrylate lenses before surgery. Contact lens wear was discontinued before surgery for 2 weeks for soft lens wearers and 3 weeks for RGP or polymethylmethacrylate lens wearers.

Surgical Procedure Before surgery, centration of the ablation zone was determined by defining the center of the undilated pupil relative the limbus using reticules in the LADARVision system software. This centration step was performed either at the preoperative examination or on the day of surgery. The pupil then was dilated using a combination of 2.5% phenylephrine (Mydfrin; Alcon Laboratories, Fort Worth, TX) and 1% tropicamide (Mydriacyl; Alcon Laboratories, Fort Worth, TX). Dilation of the pupil to at least 7 mm was required to optimize tracker performance. The laser was calibrated before each patient, which included determining that the laser energy, system alignment, and volume of material removed per laser pulse were within specification. Approximately 15 minutes before ablation, three drops of topical anesthetic were administered to the operative eye. For astigmatic treatments, a dye marker was used to mark the 3- and 9-o’clock positions on the limbus behind the slit lamp to provide a horizontal reference. The horizontal reference line was

Table 1. Preoperative Cycloplegic Refractive Parameters

Spherical hyperopia (n ⫽ 152) Mean ⫾ standard deviation Range Hyperopic astigmatism (n ⫽ 143) Mean ⫾ standard deviation Range Mixed astigmatism (n ⫽ 65) Mean ⫾ standard deviation Range D ⫽ diopters.

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Sphere (D)

Cylinder (D)

Spherical Equivalent (D)

⫹2.68 ⫾ 1.18 ⫹1.00 to ⫹6.00

⫺0.24 ⫾ 0.23 0 to ⫺0.75

⫹2.56 ⫾ 1.16 ⫹0.875 to ⫹6.00

⫹3.65 ⫾ 1.45 ⫹1.00 to ⫹6.00

⫺1.62 ⫾ 1.24 ⫺0.50 to ⫺6.00

⫹2.84 ⫾ 1.26 ⫹0.50 to ⫹5.75

⫹1.85 ⫾ 1.35 ⫹0.25 to ⫹5.00

⫺3.26 ⫾ 1.49 ⫺1.25 to ⫺6.00

⫹0.23 ⫾ 0.86 ⫺1.75 to ⫹2.375

Salz and Stevens 䡠 LADARVision for LASIK Hyperopia with Astigmatism then aligned using the LADARVision software to compensate for cyclotorsion and head tilt, thereby helping to ensure accurate on-axis correction of the astigmatism. A microkeratome was used to create a corneal flap of at least 160 ␮m in thickness and of sufficient diameter to permit the 9-mm ablation zone. The Bausch & Lomb Hansatome, Rochester, NY, microkeratome, which creates a superior hinge, was used in 98.1% of eyes, and the Paradigm Innovatome, Salt Lake City, UT which creates a nasal hinge, was used in the remaining 1.9% of eyes. The corneal flap thickness and peak ablation depth were subtracted from the preoperative pachymetry, which was 556 ⫾ 32 ␮m on average, to verify that the residual stromal thickness was at least 250 ␮m for all eyes. Pachymetry was performed after surgery only if required to assess anomalous findings. However, there were no reports of ectasia or other anomalous findings in the study. As soon as the LASIK flap was folded back, the eye tracker was engaged. All eyes in the study were tracked successfully throughout the procedure. The LADARVision eye tracker cannot be turned off during the laser ablation, which is an important safeguard for the patient. The position of the ablation zone was determined by recalling the geometry of the centration rings stored before dilation. An optic zone of 6.0 mm with a peripheral blend of 1.5 mm for a total ablation zone of 9 mm was used for spherical and astigmatic corrections. The laser pulses were applied to the cornea with an energy of 2.4 to 3.0 mJ/pulse. The fluence (energy/ area) distribution of the narrow beam at the treatment plane was approximately Gaussian. The repetition rate of the laser was 55 to 60 Hz, for an ablation rate of approximately 17 seconds per diopter of spherical hyperopia. Note that an automated nomogram adjustment was incorporated into the LADARVision system after the clinical trial, which increases the amount of correction and the ablation rate slightly to approximately 25 seconds per diopter of spherical hyperopia. Immediate postoperative pharmaceutical treatment consisted of one drop of a broad-spectrum antibiotic and, if desired, a corticosteroid and nonsteroidal anti-inflammatory drug. The antibiotic and steroid were then self-administered by the patient four times daily and tapered for up to 7 days after surgery. After cessation of this immediate postoperative drug therapy, no other medications were prescribed routinely unless medically necessary. Patients may have had the fellow eye treated on the same day as the primary eye (bilateral simultaneous) or any time thereafter, provided there were no active complications or adverse reactions for the primary eye. Retreatments were allowed at 3 months or later after the primary treatment, provided retreatment criteria were met and on approval of the Medical Director (MM). Retreatment of residual hyperopia or induced myopia were allowed if the uncorrected visual acuity (UCVA) was worse than 20/25 or the residual refractive error was 0.75 D or more and the UCVA and refraction were stable at two consecutive visits at least 1 month apart. Retreatment data were analyzed separately from the primary treatment and are not included in this analysis. The results presented herein represent a single treatment only.

Experimental Procedures The protocol follow-up schedule included 1 day and 1 week after the procedure and then 1, 3, 6, 9, 12, 18, and 24 months. Uncorrected visual acuity and best spectacle-corrected visual acuity (BSCVA) were measured under mesopic conditions using a backilluminated logarithm of minimum angle of resolution (LogMAR) chart. Uncorrected near visual acuity was assessed using a Jaeger reading card. Manifest refraction was determined using standard subjective techniques. The surgeon was involved in determination of preoperative refraction and visual acuity. To maximize reporting objectively, postoperative refractive and visual acuity exami-

nations were performed independently by residents, fellows, or both, a co-investigator who did not perform the surgery, or ophthalmic technicians, optometrists, or both under the supervision of the principal investigator. Questionnaires were administered to patients before and after surgery to assess the occurrence of symptoms and overall patient satisfaction. Before surgery, symptoms were rated on a scale of none to very severe. After surgery, the patient rated the change in symptoms from preoperative as significantly better, better, no change, worse, or significantly worse. Efficacy was based on UCVA outcomes and accuracy and stability of manifest refraction. Safety was assessed by analyzing the loss of BSCVA and the occurrence of complications or adverse reactions. As per study protocol, topography was assessed after surgery only to evaluate anomalous findings, and no anomalous findings were reported.

Results Postoperative data at 6 months are presented on 324 eyes, including 143 spherical eyes, 124 hyperopic astigmatic eyes, and 57 mixed astigmatic eyes. Data at 12 months are presented on 117 spherical eyes, 74 hyperopic astigmatic eyes, and 38 mixed astigmatic eyes. Accountability at 6 months was 95.3%, which was based on 324 eyes with available data of the 340 eyes eligible for the visit. At 12 months, accountability was 83.3%, based on 229 eyes with available data of the 275 eyes eligible. Sixteen eyes (4.7%) missed the 6-month visit and 46 (16.7%) missed the 12month visit. Three eyes were excluded from the analysis (not included in the 360 enrolled eyes) because of incorrect surgical procedure or incorrect data entry of refractive information into the laser by the surgeon, which were considered protocol deviations. At the time of analysis, follow-up data was available to 12 months. Twenty (5.6%) of the 360 total eyes enrolled were discontinued from the study before 6 months for retreatment and 85 eyes (23.6%) were discontinued before 12 months. These eyes therefore were not eligible for the 6- and 12-month visits. However, all of these eyes were included in the primary cohort analysis for each visit up to the time of retreatment. As noted previously, a nomogram adjustment of ⫹1 D added to the preoperative cycloplegic sphere was used for all eyes in this study based on analysis of an earlier hyperopia photorefractive keratectomy study. Analysis of the data in this LASIK study revealed that this nomogram adjustment resulted in slight overcorrection of low hyperopic spheres, particularly for the mixed astigmats, and undercorrection of moderate to high hyperopic spheres for both spherical hyperopia and hyperopic astigmatic eyes, which accounted for the retreatment rate. However, 73% of eyes retreated before 12 months had a UCVA of 20/40 or better before retreatment. As previously described, retreatment was permitted if the UCVA was worse than 20/25 or if the residual refractive error was 0.75 D or more and the UCVA and refraction were stable. The analysis of the LASIK data also indicated that an addition of 50% to the hyperopic sphere would be a more appropriate nomogram for all eyes.

Efficacy Distance UCVA was one of the primary efficacy outcome variables. The analysis of UCVA excluded eyes intentionally overcorrected for monovision. Before surgery, 9.5% of all eyes treated for emmetropia had a UCVA of 20/40 or better. Although the protocol required all eyes have preoperative BSCVA of at least 20/40, 53 eyes (15%) had a preoperative BSCVA worse than 20/20. Considering those eyes that had a preoperative BSCVA of

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Ophthalmology Volume 109, Number 9, September 2002 Table 2. Summary of Key Efficacy Variables Spherical Hyperopia n/N (%)

Hyperopic Astigmatism n/N (%)

Mixed Astigmatism n/N (%)

Efficacy Variables

6 Months

12 Months

6 Months

12 Months

6 Months

12 Months

UCVA 20/20 or better (if preoperative BSCVA 20/20 or better*) UCVA 20/20 or better*

57/115 (49.6) 59/121 (48.8) 83/121 (68.6) 113/121 (93.4) 93/143 (65.0) 125/143 (87.4) 141/143 (98.6)

51/95 (53.7) 51/99 (51.5) 76/99 (76.8) 93/99 (93.9) 86/116 (74.1) 106/116 (91.4) 113/116 (97.4)

38/88 (43.2) 41/110 (37.3) 66/110 (60.0) 100/110 (90.9) 75/124 (60.5) 110/124 (88.7) 123/124 (99.2)

30/52 (57.7) 34/64 (53.1) 42/64 (65.6) 60/64 (93.8) 54/74 (73.0) 66/74 (89.2) 72/74 (97.3)

18/40 (45.0) 25/54 (46.3) 40/54 (74.1) 50/54 (92.6) 37/57 (64.9) 50/57 (87.7) 57/57 (100)

15/29 (51.7) 17/36 (47.2) 26/36 (72.2) 34/36 (94.4) 28/38 (73.7) 36/38 (94.7) 38/38 (100)

UCVA 20/25 or better* UCVA 20/40 or better* MRSE ⫾ 0.50 D of intended MRSE ⫾ 1.00 D of intended MRSE ⫾ 2.00 D of intended

MRSE ⫽ manifest refraction spherical equivalent; UCVA ⫽ uncorrected visual acuity. *Not including monovision eyes. Note: Manifest refraction was not reported for one spherical hyperopic eye at 12 months.

20/20 or better at 6 and 12 months, respectively, 49.6% and 53.7% of spherical hyperopes, 43.2% and 57.7% of hyperopic astigmats, and 45.0% and 51.7% of mixed astigmats achieved a UCVA of 20/20 or better. Furthermore, postoperative UCVA at 6 and 12 months was equal to or better than preoperative BSCVA in 37% and 41% of spherical hyperopic eyes, 35% and 47% of hyperopic astigmatic eyes, and 41% and 36% of mixed astigmatic eyes, respectively. The UCVA outcomes achieved for all eyes treated for emmetropia in each refractive subset are summarized in Table 2 at 6 and 12 months. These outcomes are further stratified in Table 6 for low hyperopia (up to ⫹2.99 D) and moderate hyperopia (⫹3 up to ⫹6 D) based on preoperative spherical equivalent for spherical hyperopic and hyperopic astigmatic eyes. For spherical hyperopic eyes at 6 months, UCVA was 20/40 or better in 93.4% of eyes, including 98.9% of low hyperopic and 79.4% of moderate hyperopic eyes. At 12 months, a UCVA of 20/40 or better was achieved by 93.9%, 95.9%, and 88.5% of all spherical hyperopes, low hyperopes, and moderate hyperopes, respectively. For hyperopic astigmatic eyes at 6 months, UCVA was 20/40 or better in 90.9% of all eyes, 95.5% of low hyperopes, and 84.1% of moderate hyperopes. At 12 months, UCVA was 20/40 or better in 93.8%, 95.7%, and 88.2% for the same groups, respectively. For all mixed astigmatic eyes, UCVA was 20/40 or better in 92.6% at 6 months and 94.4% at 12 months. Uncorrected near acuity was improved in eyes treated for emmetropia, with 11% of the eyes able to read J3 or better (typical small newspaper print) before surgery as compared with 44% of the eyes at 6 months and 43% at 12 months. Although none of the eyes treated for monovision were able to read J3 or better at near uncorrected before surgery, 81% of monovision eyes were able to read J3 or better and 41% were able to read fine print (J1 or J1⫹) at 6 months after surgery. Similarly at 12 months, 87% of monovision eyes read J3 or better and 47% read J1/J1⫹. Another key efficacy outcome variable was accuracy of the manifest refraction spherical equivalent (MRSE) within 0.50 D, 1.00 D, and 2.00 D of the intended correction, including monovision corrections. Table 2 displays the percentage of eyes that achieved each level of accuracy of refraction at 6 months stratified by refractive subset. At 6 and 12 months correspondingly, 65.0%

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and 74.1% of the spherical hyperopic eyes had an MRSE within 0.50 D, whereas 87.4% and 91.4% were within 1.00 D. For hyperopic astigmatic eyes at 6 and 12 months, 60.5% and 73.0% were ⫾0.50 D of intended MRSE and 88.7% and 89.2% were ⫾1.00 D. The spherical hyperopic and hyperopic astigmatic eyes that were ⬎2 D from target at 6 months included two eyes with a preoperative refraction of more than 5 D and one eye treated for monovision. For mixed astigmatic eyes, an MRSE within 0.50 D was achieved in 64.9% of eyes at 6 months and 73.7% at 12 months, and an MRSE within 1.00 D was achieved in 87.7% and 94.7%. All mixed astigmatic eyes (100%) had an MRSE within 2.00 D of intended correction. The refractive outcomes stratified by amount of hyperopia, as shown in Table 6, reflect the general trend previously discussed for slight overcorrection of low hyperopic spheres and undercorrection of moderate to high hyperopic spheres as a result of the nomogram used in this study. Figure 3 illustrates the mean manifest spherical equivalent refractive error over time for spherical hyperopic, hyperopic astigmatic, and mixed astigmatic eyes with data at each interval through 6 and 12 months. Refractive stability was evaluated by assessing the percentage of eyes with a change of ⱕ1.00 D in manifest refraction between postoperative intervals for the cohort of eyes with data at every interval and by calculating the mean difference in manifest refraction ⫾ standard deviation (SD) between intervals, as shown in Table 3. For spherical hyperopic and hyperopic astigmatic eyes, the MRSE was used to assess stability. For mixed astigmatic eyes, the manifest refraction cylinder was used for the stability analysis because most of the correction in mixed astigmatic eyes was the cylinder component of the refraction. For eyes with data at every interval through 6 months, refractive stability was achieved in 96.4% of spherical hyperopes between 1 and 3 months and in 94.2% of eyes between 3 and 6 months. The mean difference (⫾ SD) in MRSE for spherical hyperopes between 1 and 3 months was ⫹0.11 ⫾ 0.46 D and between 3 and 6 months was ⫹0.12 ⫾ 0.48 D. Longer-term stability through 12 months was demonstrated in 95.3% or more of eyes with data at every interval and the mean difference in MRSE was less than ⫹0.05 D between the 6- and 9-month and the 9- and 12-month intervals. For hyperopic astigmats, 96.5% and 97.4% of eyes had a stable MRSE between 1 to 3 months and 3 to 6 months,

Figure 1. Example of hyperopia, hyperopic astigmatism, and mixed astigmatism algorithm.

Figure 2. Hyperopic patient age distribution.

Figure 3. Mean manifest refractive error (spherical equivalent in diopters) over time for eyes with data at each interval through 6 months.

Ophthalmology Volume 109, Number 9, September 2002 Table 3. Summary of Stability of Manifest Refraction for Eyes with Data at Each Interval* Change in Manifest Refraction between 1 and 3 Months

3 and 6 Months

6 and 9 Months

9 and 12 Months

96.4 ⫹0.11 ⫾ 0.46

94.2 ⫹0.12 ⫾ 0.48

— —

— —

96.5 ⫹0.12 ⫾ 0.50

97.4 ⫹0.07 ⫾ 0.41

— —

— —

100 ⫺0.01 ⫾ 0.39

100 ⫹0.03 ⫾ 0.34

— —

— —

97.2 ⫹0.11 ⫾ 0.40

95.3 ⫹0.13 ⫾ 0.45

96.2 ⫹0.04 ⫾ 0.55

95.3 ⫹0.01 ⫾ 0.56

100 ⫹0.02 ⫾ 0.43

95.5 ⫹0.03 ⫾ 0.44

97.0 ⫹0.07 ⫾ 0.39

100 ⫹0.09 ⫾ 0.31

100 ⫺0.07 ⫾ 0.34

100 ⫹0.08 ⫾ 0.33

97.0 ⫹0.02 ⫾ 0.35

100 ⫺0.10 ⫾ 0.34

†

6-month cohort Spherical hyperopia (n ⫽ 138) Change in MRSE ⱕ 1.00 D (%) Mean MRSE difference ⫾ SD (D) Hyperopic astigmatism (n ⫽ 115) Change in MRSE ⱕ 1.00 D (%) Mean MRSE difference ⫾ SD (D) Mixed astigmatism (n ⫽ 52) Change in MRC ⱕ 1.00 D (%) Mean MRC difference ⫾ SD (D) 12-month cohort† Spherical hyperopia (n ⫽ 106) Change in MRSE ⱕ 1.00 D (%) Mean MRSE difference ⫾ SD (D) Hyperopic astigmatism (n ⫽ 66) Change in MRSE ⱕ 1.00 D (%) Mean MRSE difference ⫾ SD (D) Mixed astigmatism (n ⫽ 33) Change in MRC ⱕ 1.00 D (%) Mean MRC difference ⫾ SD (D)

MRC ⫽ manifest refraction cylinder; MRSE ⫽ manifest refraction spherical equivalent. †

Reflects consistent cohort at each visit.

respectively. The mean difference in MRSE for these hyperopic astigmatic eyes was ⫹0.12 ⫾ 0.50 D between 1 to 3 months and ⫹0.07 ⫾ 0.41 D between 3 to 6 months. Stability was maintained in 95.5% or more of hyperopic astigmatic eyes through 12 months, with a mean difference of less than ⫹0.10 D between intervals. All of the mixed astigmatic eyes (100%) demonstrated refractive stability based on manifest refraction cylinder between all postoperative intervals through 6 months, with a mean difference (⫾SD) in manifest refraction cylinders of ⫺0.01 ⫾ 0.39 D between 1 and 3 months and ⫹0.03 ⫾ 0.34 D between 3 and 6 months. Stability of manifest cylinder through 12 months was found in 97.0% or more of eyes with a mean change of ⫹0.02 ⫾ 0.35 D between 6 and 9 months and ⫺0.10 ⫾ 0.34 D between 9 and 12 months. Accuracy of cylindrical correction was assessed by vector analysis for hyperopic astigmatic and mixed astigmatic eyes, as displayed in Table 4.3 The mean preoperative intended vector for hyperopic astigmats with 6-month data was 1.57 ⫾ 1.18 D. At 6

months, an average of 109% of the intended cylinder treatment was achieved, which reflects a tendency for slight overcorrection of the cylinder, and was more common in hyperopic astigmats eyes with low preoperative cylinder (⬍2 D). Similarly at 12 months, the average intended vector was 1.26 ⫾ 0.95 D, and the average achieved was 109%. The average angle of error for the hyperopic astigmatic eyes was 8.8 ⫾ 12.5° at 6 months and 8.5 ⫾ 13.7° at 12 months. For mixed astigmatic eyes, which had a higher mean preoperative intended vector of 3.21 ⫾ 1.46 D, 90% of the intended cylinder was achieved on average at 6 months, with a mean angle of error of 3.1 ⫾ 3.6°. The 12-month results were consistent with the 6-month results with an intended cylinder of ⫹3.10 ⫾ 1.54 D, 91% achieved, and an angle of error of 3.9 ⫾ 5.6°. There was a high level of accuracy in these mixed astigmatic eyes, as indicated by the low index of success ratio of 0.17 ⫾ 0.15 and 0.19 ⫾ 0.19 at 6 and 12 months as defined by Alpins.3 There was no induced cylinder magnitude more than 1.5 D at 6 and 12 months, except for two eyes with 2 D of induced cylinder

Table 4. Summary of Vector Analysis of Astigmatism Correction

n 6 Months Hyperopic astigmatism Mixed astigmatism 12 Months Hyperopic astigmatism Mixed astigmatism

124 57 74 38

Intended Vector (A)

Achieved Vector (B)

Difference Vector (C)

% Achieved (B/A)

Angle of Error (a)

Index of Success (CA)

1.57 ⫾ 1.18 (1.36, 1.78) 3.21 ⫾ 1.46 (2.82, 3.59)

1.48 ⫾ 0.87 (1.33, 1.64) 2.85 ⫾ 1.29 (2.51, 3.20)

0.64 ⫾ 0.64 (0.53, 0.76) 0.55 ⫾ 0.49 (0.42, 0.68)

109 ⫾ 50 (100, 118) 90 ⫾ 14 (86, 94)

8.8 ⫾ 12.5 (6.6, 11.0) 3.1 ⫾ 3.6 (2.1, 4.0)

0.49 ⫾ 0.52 (0.40, 0.58) 0.17 ⫾ 0.15 (0.13, 0.21)

1.26 ⫾ 0.95 (1.04, 1.48) 3.10 ⫾ 1.54 (2.61, 3.59)

1.28 ⫾ 0.84 (1.09, 1.47) 2.78 ⫾ 1.34 (2.36, 3.21)

0.42 ⫾ 0.46 (0.32, 0.53) 0.52 ⫾ 0.46 (0.37, 0.66)

109 ⫾ 42 (100, 119) 91 ⫾ 14 (87, 96)

8.5 ⫾ 13.7 (5.4, 11.7) 3.9 ⫾ 5.6 (2.1, 5.6)

0.42 ⫾ 0.51 (0.31, 0.54) 0.19 ⫾ 0.19 (0.13, 0.25)

Mean ⫾ standard deviation with 95% confidence interval in brackets.

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Salz and Stevens 䡠 LADARVision for LASIK Hyperopia with Astigmatism Table 5. Summary of Key Safety Variables Spherical Hyperopia n/N (%) Safety Variables Loss of more than two lines BSCVA Loss of two lines BSCVA BSCVA worse than 20/40 BSCVA worse than 20/25 (if 20/20 or better before surgery)

Hyperopic Astigmatism n/N (%)

Mixed Astigmatism n/N (%)

6 Months

12 Months

6 Months

12 Months

6 Months

12 Months

0/141 (0.0) 5/141 (3.5) 0/141 (0.0) 2/132 (1.5)

0/116 (0.0) 4/116 (3.4) 0/116 (0.0) 1/110 (0.9)

0/121 (0.0) 7/121 (5.8) 0/124 (0.0) 3/101 (3.0)

0/72 (0.0) 1/72 (1.4) 0/74 (0.0) 0/62 (0.0)

0/52 (0.0) 1/52 (1.9) 0/56 (0.0) 0/41 (0.0)

0/36 (0.0) 0/36 (0.0) 0/38 (0.0) 0/31 (0.0)

BSCVA ⫽ best spectacle-corrected visual acuity. Note: BSCVA was not reported for one spherical hyperopic eye at 12 months.

at 12 months resulting from unstable refractions. These two eyes had, 1-D or less cylinder at the 6- and 9-month visits, with an increase in refractive cylinder at 12 months despite stable topographies. Both patients were taking systemic medications with blurred vision listed as a side effect, and both patients had a 1.50 D or less cylinder at the following visit. An induced cylinder mag-

nitude more than 1 D was observed in 4.2% and 7.8% of spherical hyperopes at 6 months and 12 months, respectively, and in none of the hyperopic astigmatic or mixed astigmatic eyes at either interval. Vector analysis of induced cylinder in spherical hyperopic eyes showed that the mean preoperative cylinder vector was ⫺0.24 ⫾ 0.23 D (n ⫽ 152) and the mean postoperative cylinder

Table 6. Summary of Key Safety and Efficacy Outcomes Stratified by Preoperative Spherical Equivalent Spherical Hyperopia n/N (%) Preoperative Spherical Equivalent 6 Months UCVA 20/20 or better (if preoperative BSCVA 20/20 or better*) UCVA 20/20 or better* UCVA 20/25 or better* UCVA 20/40 or better* MRSE ⫾0.50 D of intended MRSE ⫾1.00 D of intended MRSE ⫾2.00 D of intended Loss of more than two lines BSCVA Loss of two lines BSCVA BSCVA worse than 20/40 BSCVA worse than 20/25 (if 20/20 or better before surgery) 12 Months UCVA 20/20 or better (if preoperative BSCVA 20/20 or better†) UCVA 20/20 or better* UCVA 20/25 or better* UCVA 20/40 or better* MRSE ⫾0.50 D of intended MRSE ⫾1.00 D of intended MRSE ⫾2.00 D of intended Loss of more than two lines BSCVA Loss of two lines BSCVA BSCVA worse than 20/40 BSCVA worse than 20/25 (if 20/20 or better before surgery)

Hyperopic Astigmatism n/N (%)

Low (⫹0.88 to ⫹2.9)

Moderate (⫹3 to ⫹6)

Low (⫹0.5 to ⫹2.9)

Moderate (⫹3 to ⫹5.75)

48/86 (55.8)

9/29 (31.0)

25/54 (46.3)

13/34 (38.2)

47/87 (54.0) 66/87 (75.9) 86/87 (98.9) 77/104 (74.0) 98/104 (94.2) 103/104 (99.0) 0/103 (0.0) 4/103 (3.9) 0/104 (0.0) 2/100 (2.0)

10/34 (29.4) 17/34 (50.0) 27/34 (79.4) 16/39 (41.0) 27/39 (69.2) 38/39 (97.4) 0/38 (0.0) 1/38 (2.6) 0/38 (0.0) 0/32 (0.0)

27/66 (40.9) 46/66 (69.7) 63/66 (95.5) 53/76 (69.7) 72/76 (94.7) 76/76 (100) 0/74 (0.0) 3/74 (4.1) 0/76 (0.0) 0/63 (0.0)

14/44 (31.8) 20/44 (45.5) 37/44 (84.1) 22/48 (45.8) 38/48 (79.2) 47/48 (97.9) 0/47 (0.0) 4/47 (8.5) 0/48 (0.0) 3/38 (7.9)

40/72 (55.6)

11/23 (47.8)

25/39 (64.1)

5/13 (38.5)

40/73 (54.8) 60/73 (82.2) 70/73 (95.9) 69/88 (78.4) 82/88 (93.2) 87/88 (98.9) 0/88 (0.0) 4/88 (4.5) 0/88 (0.0) 1/85 (1.2)

11/26 (42.3) 16/26 (61.5) 23/26 (88.5) 17/28 (60.7) 24/28 (85.7) 26/28 (92.9) 0/28 (0.0) 0/28 (0.0) 0/28 (0.0) 0/25 (0.0)

28/47 (59.6) 33/47 (70.2) 45/47 (95.7) 42/54 (77.8) 50/54 (92.6) 53/54 (98.1) 0/52 (0.0) 1/52 (1.9) 0/54 (0.0) 0/46 (0.0)

6/17 (35.3) 9/17 (52.9) 15/17 (88.2) 12/20 (60.0) 16/20 (80.0) 19/20 (95.0) 0/20 (0.0) 0/20 (0.0) 0/20 (0.0) 0/16 (0.0)

BSCVA ⫽ best spectacle-corrected visual acuity; MRSE ⫽ manifest refraction spherical equivalent. *Not including monovision eyes. Note: MRSE and BSCVA were not reported for one spherical moderate hyperopic eye at 12 months.

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Ophthalmology Volume 109, Number 9, September 2002 Table 7. Summary of Complications and Adverse Reactions at Any Time in the Postoperative Course to 12 Months

Spherical Hyperopia, n (%)

Hyperopic Astigmatism, n (%)

Mixed Astigmatism, n (%)

All Eyes (N ⫽ 152)*

Low 0.8–2.9 (N ⫽ 110)*

High 3–6 (n ⫽ 42)*

All Eyes (N ⫽ 143)*

Low 0.5–2.9 (n ⫽ 84)*

High 3–5.75 (n ⫽ 59)*

All Eyes (N ⫽ 65)*

2 (1.3) 1 (0.7) 4 (2.6) 7 (4.6) 2 (1.3) 4 (2.6)

2 (1.8) 1 (0.9) 3 (2.7) 3 (2.7) 2 (1.8) 1 (0.9)

0 (0.0) 0 (0.0) 1 (2.4) 4 (9.5) 0 (0.0) 3 (7.1)

3 (2.1) 0 (0.0) 4 (2.8) 7 (4.9) 2 (1.4) 4 (2.8)

3 (3.6) 0 (0.0) 2 (2.4) 5 (6.0) 2 (2.4) 2 (2.4)

0 (0.0) 0 (0.0) 2 (3.4) 1 (1.7) 0 (0.0) 2 (3.4)

0 (0.0) 1 (1.5) 1 (1.5) 2 (3.1) 0 (0.0) 2 (3.1)

0 (0.0) 0 (0.0) 3 (2.0)

0 (0.0) 0 (0.0) 1 (0.9)

0 (0.0) 0 (0.0) 2 (4.8)

0 (0.0) 2 (1.4) 0 (0.0)

0 (0.0) 0 (0.0) 0 (0.0)

0 (0.0) 2 (3.4) 0 (0.0)

1 (1.5) 1 (1.5) 0 (0.0)

Complications† Corneal edema 1 week to 1 month Corneal folds or striae Double or ghost images Epithelium in interface Foreign body sensation ⱖ1 month Sterile interface inflammation Adverse reactions‡ IOP increase ⬎10 mmHg Miscreated flap (microkeratome related) Peripheral sterile corneal infiltrates

*Stratified by preoperative spherical equivalent (in diopters). Other complications that occurred at a rate of less than 1% included central epithelial defect ⬍1 week, intralamellar haze, misaligned flap, pain at 1 month or later. †

‡ Other adverse reactions that occurred at a rate of less than 1% included rolled flap edge with trace corneal melt, and myocardial infarction at 3 weeks after retreatment, which was unrelated to the procedure.

vector was ⫺0.51 ⫾ 0.39 D (n ⫽ 143) at 6 months and ⫺0.47 ⫾ 0.44 D (n ⫽ 116) at 12 months.

Safety A key safety outcome in evaluation of the LASIK procedure was the postoperative BSCVA and the change in BSCVA from preoperative, as summarized in Table 5. A loss of two lines of BSCVA at 6 months occurred in 3.5% of the spherical hyperopic eyes, 5.8% of the hyperopic astigmatic eyes, and 1.9% of the mixed astigmatism group. At 12 months, a loss of two lines occurred in 3.4% of spherical hyperopic eyes, 1.4% of hyperopic astigmatic eyes, and in none of the mixed astigmatic eyes. No eyes (0%) had a loss of more than two lines of

BSCVA at 6 or 12 months. All eyes (100%) had a BSCVA of 20/40 or better at both intervals. For those eyes that had a BSCVA of 20/20 or better before surgery, two (1.5%) of the spherical hyperopic eyes, three (3.0%) of the hyperopic astigmatic eyes, and none (0%) of the mixed astigmatic eyes had a 6-month postoperative BSCVA worse than 20/25. These five spherical and hyperopic astigmatic eyes were corrected to 20/32 at 6 months. At 12 months, only the spherical hyperopic group had one eye (0.9%) with a preoperative BSCVA of 20/20 and a postoperative BSCVA of 20/32. These safety outcomes are also displayed in Table 6 for the low and moderate hyperopic eyes at 6 and 12 months. The occurrence of complications and adverse reactions, as reported by the investigators, was another key safety outcome. A

Table 8. Summary of Patient Symptoms Reported Significantly Worse.* Spherical Hyperopia, n (%)

Blurring of vision Burning Double vision Dryness Feeling of something in eye Fluctuation of vision Glare Halos Headache Light sensitivity Night driving difficulty Pain Redness

Hyperopic Astigmatism, n (%)

6 Months (n ⫽ 133)†

12 Months (n ⫽ 114)

6 Months (n ⫽ 113)‡

12 Months (n ⫽ 71)§

6 Months (n ⫽ 53)

12 Months (n ⫽ 33)

2 (1.5) 1 (0.8) 2 (1.5) 4 (3.0) 2 (1.5) 8 (6.0) 1 (0.8) 3 (2.3) 0 (0.0) 2 (1.5) 3 (2.3) 1 (0.8) 1 (0.8)

0 (0.0) 0 (0.0) 0 (0.0) 7 (6.1) 4 (3.5) 3 (2.6) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0)

2 (1.8) 2 (1.8) 4 (3.6) 6 (5.3) 3 (2.7) 2 (1.8) 2 (1.8) 5 (4.5) 2 (1.8) 2 (1.8) 2 (1.8) 1 (0.9) 3 (2.7)

1 (1.4) 1 (1.4) 0 (0.0) 6 (9.0) 0 (0.0) 1 (1.4) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 2 (2.9) 3 (4.3)

2 (3.8) 0 (0.0) 0 (0.0) 1 (1.9) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 4 (7.5) 0 (0.0) 0 (0.0)

0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 2 (6.1) 0 (0.0) 0 (0.0) 2 (6.1) 0 (0.0) 0 (0.0)

*Same patient may represent more than one symptom. No patients reported significantly worse excessive tearing. (n ⫽ 132–133) for several symptoms. Ratings for some symptoms were not reported for one eye. (n ⫽ 110 –112) for several symptoms. Ratings for some symptoms were not reported for one to three eyes. § (N ⫽ 69 –70) for several symptoms. Ratings for some symptoms were not reported for one to two eyes. † ‡

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Mixed Astigmatism, n (%)

Salz and Stevens 䡠 LADARVision for LASIK Hyperopia with Astigmatism Table 9. Summary of Previously Published Hyperopia Laser In Situ Keratomileusis Results

Cylinder

Uncorrected Visual Acuity <20/40 (%)

Manifest Retraction Spherical Equivalent ⴞ1D (%)

Bestcorrected Visual Acuity >2 lines (%)

– – – – – – – – – – – – –

95 90 72.2 94.1 100 87.8 95 93 50 81 95.6 77.8 97.2

85 58 81.5 100 95.3 71.4 91 85 50 71 88.9 51.8 93.2

5 4.3 6.8 0 2.0 0 0 0 13 6 0 1.4 4.5

Refractive Range (D)

Author Spherical hyperopia Ditzen et al (1998)5

Laser MEL 60

Follow-up (mos) 12

Go¨ ker et al (1998)6 Argento et al (1998)8

Keracor 116 Keracor 116/117

Arbelaez et al (1999)9

Keracor 117C

Esquenazi et al (1999)12 Zadok et al (2000)13

Keracor 117CT Nidek EC-5000

6 6

Salz et al (present study)

LADARVision

12

6 6 12

n 20 23 54 138 153 170 24 20 16 92 45 27 88

Spherical Equivalent ⫹1.00 ⫹4.25 ⫹4.25 ⫹1.25 ⫹2.25 ⫹5.50 ⫹1.00 ⫹3.10 ⫹5.10 ⫹1.25 ⫹1.00 ⫹3.00 ⫹0.88

to to to to to to to to to to to to to

⫹4.00 ⫹8.00 ⫹8.00 ⫹2.50 ⫹4.75 ⫹8.50 ⫹3.00 ⫹5.00 ⫹9.00 ⫹8.50 ⬍⫹3.00 ⫹5.00 ⫹2.99

29 ⫹3.00 to ⫹6.00 Simple and compound hyperopic astigmatism and mixed astigmatism Argento et al (1997)4 Keracor 116/117 6 11 ⫹1.00 to ⫹2.50 53 ⫹2.50 to ⫹4.25 51 ⫺0.88 to ⫹4.25 Chayet et al (1998)7 Nidek EC-5000 3 41* ⫹0.67 ⫾ 1.33† Arbelaez et al (1999)9 Keracor 117C 12 23 ⫹1.00 to ⫹3.00 14 ⫹3.10 to ⫹5.00 13 ⫹5.10 to ⫹9.50 Lindstrom et al VISX Star S2 6 46 ⫹0.50 to ⫹6.0 (1999)10 Barraquer et al (1999)11 Schwind-Keratom 6 18 ⫹1.50 to ⫹3.50

–

88.5

85.7

0

⫹2.00 to ⫹5.00 ⫹2.00 to ⫹5.75 ⫹0.50 to ⫹7.25 ⫺3.82 ⫾ 0.95† ⫹1.00 to ⫹7.50 ⫹1.00 to ⫹7.50 ⫹1.00 to ⫹7.50 0 to ⫹5.0

90.1 73.6 92.2 85 78 82 25 79

81.9 95.9 100 90 83 58 17 63

0 3.8 3.9 0 0 14 15 0

30 18 54

⫹3.51 to ⫹6.00 ⫹6.01 to ⫹10.0 ⫹0.50 to ⫹2.99

0 to ⫺4.50 0 to ⫺4.00 ⫺0.50 to ⫺6.00

20 38

⫹3.00 to ⫹5.75 ⫺1.75 to ⫹2.375

⫺0.50 to ⫺6.00 ⫺1.25 to ⫺6.00

Salz et al (present study)

LADARVision

12

0 to ⫺5.00

71 for all eyes

100

0 for all eyes

95.7

80 77 92.6

1.9

88.2 94.4

80.0 94.7

0 0

BCVA ⫽ best-corrected visual acuity; MRSE⫽manifest refraction spherical equivalent; SE⫽spherical equivalent; UCVA⫽uncorrected visual acuity. *Includes simple myopic astigmatism eyes. †

Mean ⫾ standard deviation only (range not reported).

summary of complications and adverse reactions that occurred at any time in the study to 12 months is detailed in Table 7, with stratification into low and moderate hyperopic eyes. The most common complications reported in less than 5% of all spherical hyperopic, hyperopic astigmatic, and mixed astigmatic eyes included: epithelium in the interface, sterile interface inflammation, double or ghost images, corneal edema at 1 week to 1 month, corneal folds or striae, and foreign body sensation at 1 month or later. All other reported complications occurred at a rate of less than 1%, including central epithelial defect at less than 1 week, intralamellar haze, misaligned flap, and pain at 1 month or later. All of these eyes with a complication had a BSCVA of 20/25 or better at the last reported visit, except for one eye, which was 20/32 before surgery and at the last reported visit. Nine (2.5%) adverse reactions were reported in the study, including three eyes with a microkeratome-related miscreated flap (1.4% hyperopic astigmats, 1.5% mixed astigmats); three eyes with peripheral sterile corneal infiltrates (2.0% spherical hyperopes); and one eye with an increase in intraocular pressure ⬎10 mmHg from preoperative (1.5% mixed astigmats). In addition, one hyperopic astigmatic

eye had a rolled corneal flap edge with trace corneal melt that resolved with no loss of BSCVA, which was 20/16 at 6 months. Another patient experienced a myocardial infarction 3 weeks after retreatment, which was considered unrelated to the device or to the LASIK procedure. All of these eyes with adverse reactions had a BSCVA of 20/25 or better at the last reported visit, except for two eyes with microkeratome-related miscreated flaps, which were 20/32 and 20/40 best corrected. Other corneal findings noted during examinations at 1 month or later that were not considered complications or adverse reactions by the investigator included superficial punctate keratitis, interface debris, epithelial opacities, wrinkle or striae, iron ring or line, isolated cells in the interface, irregular epithelium, abrasion, and vacuoles. Other anterior segment findings at 1 month or later not considered complications or adverse reactions included allergic conjunctivitis, lagophthalmos, conjunctival injection, and subconjunctival hemorrhage. Fifteen eyes of nine patients, who were 59 to 73 years old, had age-related crystalline lens findings noted after but not before surgery. Only one eye had a BSCVA loss of two lines associated with the lens changes, which occurred at the 9-month visit. Three eyes had fundus

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Ophthalmology Volume 109, Number 9, September 2002 findings noted after but not before surgery, including drusen in both eyes of a patient and a cotton wool spot in another patient, which was most likely related to a systemic condition. None of the eyes with fundus findings had a loss of BSCVA from preoperative. These lens and fundus findings were not considered to be related to the procedure.

Subjective Symptoms and Patient Satisfaction Table 8 summarizes subjective symptoms reported as significantly worse at 6 and 12 months as compared with before surgery on a patient questionnaire for spherical hyperopic, hyperopic astigmatic, and mixed astigmatic eyes. The patient symptoms most commonly reported as significantly worse at a rate of 9.0% or less were dryness, difficulty with night driving, fluctuation of vision, halos, blurring of vision, double vision, feeling of something in the eye, redness, and pain. All other symptoms were reported as significantly worse, at a rate of less than 2%, including burning, glare, headache, light sensitivity, and excessive tearing. Overall, at least 75.9% of spherical hyperopic patients, 67.9% of hyperopic astigmatic patients, and 77.4% of mixed astigmatic patients were satisfied or extremely satisfied with the results of their surgery at 6 months. At 12 months, 79.8% of spherical hyperopic patients, 84.3% of hyperopic astigmatic patients, and 75.8% of mixed astigmatic patients were satisfied or extremely satisfied. The quality of vision at 6 months was unchanged, better, or significantly better as compared with preoperative quality in 95.6% of spherical hyperopic patients, 94.8% of hyperopic astigmatic patients, and 94.3% of mixed astigmatic patients, respectively. Quality of vision was reported as unchanged, better, or significantly better at 12 months in 96.5% of spherical hyperopes, 94.4% of hyperopic astigmats and 97.0% of mixed astigmats, respectively. At 6 months, 94.5% of spherical hyperopic patients, 85.6% of hyperopic astigmatic patients, and 80.8% of mixed astigmatic patients reported never wearing corrective lenses for distance. At 12 months, 95.6%, 80.6%, and 78.8% of patients in these same groups reported never wearing corrective lenses for distance.

Discussion Laser in situ keratomileusis for correcting hyperopia proved to be more challenging than correcting myopia, primarily for two reasons. The excimer lasers had to be capable of delivering peripheral laser pulses to flatten the peripheral cornea to steepen the central cornea. To accomplish this with LASIK, larger diameter flaps had to be produced by a new generation of microkeratomes. There are now several laser systems capable of hyperopic ablations and several microkeratomes capable of creating large-diameter flaps. Results of LASIK for hyperopia with and without astigmatism have been reported by multiple authors. The results reported in this paper compare favorably with other published reports (Table 9).4 –13 The results summarized in Table 9 show that several excimer laser systems are capable of adequately correcting hyperopia with or without astigmatism up to a spherical equivalent of approximately ⫹5 D. Above that amount, efficacy as determined by UCVA or proximity to emmetropia falls off dramatically. Only the report by Ibrahim14 with the Nidek laser and the report by Reviglio et al15 with the LaserSight system (LaserSight, Orlando, FL) revealed relatively poor outcomes in the correction of hyperopia. The Ibrahim study with the Nidek must be balanced with the report of Chayet et al,8 who pre-

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sumably used a more refined algorithm with the same laser system, which described generally favorable results. In contrast to the other studies summarized above, the present study includes larger cohorts for the subgroups of spherical hyperopia, hyperopic astigmatism, and mixed astigmatism, better 6-month accountability, and multiple surgeons operating at six separate sites. The results presented are equal to or better than the smaller single-site studies previously published. All three subgroups of patients achieved excellent outcomes, with more than 90% achieving 20/40 or better UCVA and almost 90% of the eyes corrected to within IAD of emmetropia. Nomogram adjustment of adding 50% to the spherical component of the correction to compensate for the trends observed in spherical hyperopic and hyperopic and mixed astigmatic eyes may improve UCVA and refractive outcomes further. These results also demonstrate refractive stability to 12 months; low loss of two lines or fewer of BSCVA; good near UCVA; and a low occurrence of vision-threatening complications and patient symptoms. In conclusion, the LADARVision excimer laser system safely and effectively corrects low to moderate spherical and astigmatic hyperopia as well as mixed astigmatism.

Appendix LADARVision LASIK Hyperopia Study Group Jonathan D. Carr, MD, Atlanta, Georgia; Jonathan M. Frantz, MD, Fort Myers Florida; Alan M. Kozarsky, MD, Atlanta, Georgia; Ezra Maguen, MD, Los Angeles, California; Marguerite B. McDonald, MD, New Orleans, Louisiana; Anthony B. Nesburn, MD, Los Angeles, California; Francis W. Price, Jr, MD, Indianapolis, Indiana; Yaron S. Rabinowitz, MD, Los Angeles, California; James J. Salz, MD, Los Angeles, California; R. Doyle Stulting, MD, Atlanta, Georgia; Keith P. Thompson, MD, Atlanta, Georgia; Thomas S. Tooma, MD, Newport Beach, California; George O. Waring, MD, Atlanta, Georgia; William E. Whitson, MD, Indianapolis, Indiana.

References 1. McDonald MB, Deitz MR, Frantz JM, et al. Photorefractive keratectomy for low-to-moderate myopia and astigmatism with a small-beam, tracker-directed excimer laser. Ophthalmology 1999;106:1481–9. 2. McDonald MB, Carr JD, Frantz JM, et al. Laser in situ keratomileusis for myopia up to ⫺11D with up to ⫺5D of astigmatism with the Summit Autonomous LADARVision excimer laser system. Ophthalmology 2001;108:309 –16. 3. Alpins N A. A new method of analyzing vectors for changes in astigmatism. J Cataract Refract Surg 1993;19:524 –33. 4. Argento CJ, Cosentino MJ, Biondini A. Treatment of hyperopic astigmatism. J Cataract Refract Surg 1997;23:1480 –90. 5. Ditzen K, Huschka H, Pieger S. Laser in situ keratomileusis for hyperopia. J Cataract Refract Surg 1998;24:42–7. 6. Go¨ ker S, Er H, Kahvecioglu C. Laser in situ keratomileusis to correct hyperopia from ⫹4.25 to ⫹8.00 diopters. J Refract Surg 1998;14:26 –30.

Salz and Stevens 䡠 LADARVision for LASIK Hyperopia with Astigmatism 7. Chayet AS, Magallanes R, Montes M, et al. Laser in situ keratomileusis for simple myopic, mixed, and simple hyperopic astigmatism. J Refract Surg 1998; 14(Suppl): S175– 6. 8. Argento CJ, Cosentino MJ. Laser in situ keratomileusis for hyperopia. J Cataract Refract Surg 1998;24:1050 – 8. 9. Arbelaez MC, Knorz MC. Laser in situ keratomileusis for hyperopia and hyperopic astigmatism. J Refract Surg 1999; 15:406 –14. 10. Lindstrom RL, Hardten DR, Houtman DM, et al. Six-month results of hyperopic and astigmatic LASIK in eyes with primary and secondary hyperopia. Trans Am Ophthalmol Soc 1999;97:241–55. 11. Barraquer C, Gutie´ rrez AM. Results of laser in situ keratom-

12. 13. 14. 15.

ileusis in hyperopic compound astigmatism. J Cataract Refract Surg 1999;25:1198 –204. Esquenzai S, Mendoza A. Two-year follow-up of laser in situ keratomileusis for hyperopia. J Refract Surg 1999;15:648 –52. Zadok D, Maskaleris G, Montes M, et al. Hyperopic laser in situ keratomileusis with the Nidek EC-5000 excimer laser. Ophthalmology 2000;107:1132–7. Ibrahim O. Laser in situ keratomileusis for hyperopia and hyperopic astigmatism. J Refract Surg 1998;14(Suppl):S179 – 82. Reviglio VE, Luna JD, Rodriguez ML, et al. Laser in situ keratomileusis using the LaserSight 200 laser: results of 950 consecutive cases. J Cataract Refract Surg 1999;25: 1062– 8.

Discussion by Ronald R. Krueger, MD The scanning spot delivery and “laser radar” eye tracking of the LADARVision system is unique among previously used lasers for the above indications. The spot diameter of less than 0.9 mm with a pulse energy of 2.0 to 2.4 mJ is among the smallest in beam diameter and the highest in energy density. Several hundred to a few thousand pulses are required for a typical treatment. At a pulse frequency of 55 to 60 Hz, the treatment time for hyperopia and hyperopic astigmatism is only 17 seconds per diopter. The LADARVision tracking system (laser radar) is essential for accurate spot placement and is required during the laser ablation. The very fast detection frequency of 4000 Hz is more than an order of magnitude greater than in other video camera-based trackers.1 This leads to a response of less than 3 msec rise time, which is more than an order of magnitude faster as well. This very fast eye tracking is necessary to follow fixation-related saccades adequately. The following can occur 5 times/second with a magnitude of up to 1 mm and a speed of 100 mm per second. The LADARVision algorithm for the treatment of hyperopia, hyperopic astigmatism, and mixed astigmatism is one fundamental algorithm that is used to calculate all the shot patterns. The cumulative ablation is achieved by partial overlap of the many laser shots. The calculated pattern achieves the entire correction in a single pass, unlike that of other laser systems for the same indications. For consistency, a negative cylinder convention is used for all the treatments. This allows for smooth continuity in treating various levels of hyperopia with astigmatism and mixed astigmatism. The third point of discussion, which was brought up in this study, is that of the adjustment in the hyperopic nomogram, which is necessary during clinical ablation, as in this study. Initial studies with polymethyl methacrylate demonstrate accurate ablation of all profile types (myopic and hyperopic) when using the LADARVision system. Early clinical experience with hyperopic treatments, however, reveal consistent undercorrection such that at least 1 diopter D should be added to positive spherical prescriptions. As indicated by the authors, every patient in this current study had ⫹1 D added to the preoperative sphere to determine the treatment prescription. The study results showed no significant overcorrection of more than 1 D, but there was some undercorrection. Why must this additional 1 D be added to the clinical treatment algorithm when it is not necessary experimentally? The authors suggest that it may be either a biologic or a biomechanical effect. This

From the Cole Eye Institue, Cleveland Clinic Foundation, Cleveland, Ohio. Address correspondence to Ronald R. Krueger, MD, Cole Eye Institute, Cleveland Clinic Foundation, 9500 Enclid Areme, 132, Cleveland, 04 44195.

includes things like wound healing, the geometry and physics of ablation, and the structural integrity of the cornea. One additional explanation, which may play a large role, regards the curvature of the cornea, which would result in an acute angle of incidence for peripheral pulses striking the corneal surface. Initial studies have shown significant reflection of laser energy of nearly 50% for pulses outside a 7.2-mm zone and 100% for pulses at a zone of 9 mm (T Seiler personal communication, October 2000). These multiple theories lead to an important question about the physical dynamics of hyperopic treatment that needs further investigation. Finally, the last point of discussion is whether the LADARVision correction of spherical hyperopia, hyperopic astigmatism, and mixed astigmatism is safe and effective. The authors have hypothesized safety and efficacy as the purpose of this study, and their clinical experience and outcome demonstrates, no patient lost more than two lines of best spectacle-corrected visual acuity. An average of 4.1% lost two lines. Breaking this down into the individual component groups, loss of two lines of best spectacle-corrected visual acuity occurred in only 1.9% of the mixed astigmatism group and 3.5% of the spherical hyperopia group, but in 5.8% of the hyperopic astigmatism group. Why does this latter group have a higher percentage of eyes with loss of two lines of best spectacle-corrected visual acuity. The reason can be explained by the more complex nature of treating hyperopia with astigmatism and the greater magnitude of treatment in comparison with mixed astigmatism. Adverse reactions were only reported in 9 eyes (2.5%), which included microkeratome-related miscreated flaps, peripheral sterile infiltrates, and intraocular pressure change. Each of these is not unique to the correction of hyperopia or treatment with this laser. Overall, it appears that LADARVision correction of hyperopia, hyperopic astigmatism, and mixed astigmatism is a safe procedure. With regard to the efficacy of LADARVision laser in situ keratomilensis, 44% had an uncorrected visual acuity of 20/20 or better, and 92% were 20/40 or better. Breaking this down to the component groups, the uncorrected visual acuity was 20/20 or better in 46.3% of mixed astigmatic eyes and 48.8% of spherical hyperopic eyes, but in only 37.3% of hyperopic astigmatic eyes. Similarly, the accuracy of the spherical manifest refraction was within 0.5 D in 63% of eyes and within 1 D in 88%. Breaking this down in its component groups, the manifest refraction spherical equivalent was within 0.5 D in 64.9% of mixed astigmatic eyes, 65.0% of hyperopic eyes, and 60.5% of hyperopic astigmatic eyes. Once again, this latter group of hyperopic eyes with astigmatism has the lowest percentages with regard to efficacy, and the reasons, may again be explained by the greater magnitude and complexity of the treatment. Finally, all three groups had an intended manifest refraction spherical equivalent, within 1 D of emmetropia in approximately

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