Laser in situ keratomileusis for refractive error after cataract surgery

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) to correct refractive error following cataract surgery. SETTING: The Eye Institute, Sydney, Australia. METHODS: This retrospective study reviewed 23 eyes (19 patients; 10 female, 9 male) treated with LASIK for refractive error following cataract surgery. The Summit Apex Plus and Ladarvision excimer laser and the SKBM microkeratome were used. The mean age was 63.5 years (range 50 to 88 years). The mean length of follow-up was 8.4 months (range 1 to 12 months) and mean interval between cataract surgery and LASIK was 12 months (range 2.5 to 46 months). RESULTS: The mean preoperative spherical equivalent refraction (SEQ) for myopic eyes was -3.08 +/- 0.84 diopters (D) (range -4.75 to -2.00 D) and for hyperopic eyes was +1.82 +/- 1.03 D (range +0.75 to +3.00 D). The mean improvement following LASIK surgery was greater for myopic than hyperopic eyes (myopic, 2.54 +/- 1.03 D versus hyperopic, 1.73 +/- 0.62 D; P=.033). The percentage of patients within +/-0.5 D of intended refraction post-LASIK surgery was 83.3% for myopic eyes and 90.9% for hyperopic eyes and all eyes were within +/-1.0 D of intended (P<.001). The percentage of eyes with uncorrected visual acuity of 20/40 or better in the myopic group improved from none preoperatively to 91.7% postoperatively (P<.001) and in the hyperopic group improved from 27.3% preoperatively to 90.9% postoperatively (P=.008). No eyes lost 2 or more lines of best corrected visual acuity. CONCLUSION: Laser in situ keratomileusis appears to be effective in correcting refractive error following cataract surgery. Longer-term studies are required to determine refractive stability.     

Photorefractive keratectomy after cataract surgery in uncommon cases: long-term results

AIM: To evaluate the efficacy and safety of the excimer laser correction of the residual refractive errors after cataract extraction with intraocular lens (IOL) implantation in uncommon cases. METHODS: Totally 24 patients with high residual refractive error after cataract surgery with IOL implantation were examined. Twenty-two patients had a history of phacoemulsification and IOL implantation, and two had extra-capsular cataract extraction with IOL implantation. Detailed examination of preoperative medical records was done to explain the origin of the post-cataract refractive errors. All patients underwent photorefractire keratectomy (PRK) enhancement. The mean outcome measures were refraction, uncorretted visual acuity (UCVA), best corrected visual acuity (BCVA) and corneal transparency and follow up ranged from 1 to 8y. RESULTS: The principal causes of residual ametropia was inexact IOL calculation in abnormal eyes with high myopia and congenital lens abnormalities, followed by corneal astigmatism both suture induced and preexisting. After cataract surgery and before the laser enhancement the mean spherical equivalent (SE) was -0.56±3 D ranging from -4.62 to +2.25 D in high myopic patients, instead it was -1±1.73 D ranging from -3.25 to +3.75 D in the astigmatic eyes, with a mean cylinder of -3.75±0 ranging from -3 to +5.50 D. After laser refractive surgery the mean SE was 0.1±0.73, ranging from -0.50 to +1.50 in the myopic group, and it was -0.50±0.57 ranging from -1.25 to +0.50 in astigmatic patients, with a mean cylinder of -0.25±0.75. In myopic patients the mean UCVA and BCVA were 0.038±0.072 logMAR and 0.018±0.04 respectively, both ranging from 0.10 to 0.0. In astigmatic patients, the mean UCVA and BCVA were 0.213±0.132 and 0.00±0.0 respectively, UCVA ranging from 0.50 to 0.22 and BCVA was 0.00. All patients presented normal corneal transparency. No ocular hypertension was detected and no corneal haze was observed. All registered values remained stable also at the end line evaluation. CONCLUSION: The excimer laser treatment of residual refractive errors after cataract surgery with IOL implantation in abnormal eyes resulted in satisfactory and stable visual outcome with good safety and efficacy.     

【In Press】Photorefractive keratectomy after cataract surgery in uncommon cases. Long-term results

AIM: To evaluate the efficacy and safety of the excimer laser correction of the residual refractive errors after cataract extraction with intraocular lens (IOL) implantation in uncommon cases. METHODS: 24 patients with high residual refractive error after cataract surgery with IOL implantation were examined. Twenty-two patients had a history of phacoemulsification and IOL implantation, and two had extra-capsular cataract extraction with IOL implantation. Detailed examination of preoperative medical records was done to explain the origin of the post-cataract refractive errors. All patients underwent PRK enhancement. The mean outcome measures were refraction, UCVA, BCVA and corneal transparency and follow up ranged from 1 to 8y. RESULTS: The principal causes of residual ametropia was inexact IOL calculation in abnormal eyes with high myopia and congenital lens abnormalities, followed bycorneal astigmatism both suture induced and preexisting. After cataract surgery and before the laser enhancement the mean SE was -0.56±3 D ranging from -4.62 to +2.25 D in high myopic patients, instead it was -1±1.73 D ranging from -3.25 to +3.75 D in the astigmatic eyes, with a mean cylinder of -3.75±0 ranging from -3 to +5.50. After laser refractive surgery the mean SE was 0.1±0.73, ranging from -0.50 to +1.50 in the myopic group, and it was -0.50 ±0.57 ranging from -1.25 to +0.50 in astigmatic patients, with a mean cylinder of -0.25 ±0.75. In myopic patients the mean UCVA and BCVA were 0.038 Log MAR ±0.072 and 0.018 ±0.04 respectively, both ranging from 0.10 to 0.0. In astigmatic patients, the mean UCVA and BCVA were 0.213±0.132 and 0.00±0.0 respectively: UCVA ranging from 0.50 to 0.22 and BCVA was 0.00. All patients presented normal corneal transparency. No ocular hypertension was detected and no corneal haze was observed. All registered values remained stable also at the end line evaluation. CONCLUSIONS: The excimer laser treatment of residual refractive errors after cataract surgery with IOL implantation in abnormal eyes resulted in satisfactory and stable visual outcome with good safety and efficacy.     

Laser in situ keratomileusis for correction of induced astigmatism from cataract surgery

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) to correct residual astigmatism after cataract surgery. METHODS: LASIK was performed on 20 eyes of 20 patients with refractive myopic or mixed astigmatism (3.00 to 6.00 D) at least 1 year after extracapsular cataract extraction with posterior chamber intraocular lens implantation without complication. Each eye received bitoric LASIK with the Nidek EC-5000 excimer laser and the Automated Corneal Shaper microkeratome. RESULTS: At 6 months after LASIK, mean refractive cylinder decreased from 4.64+/-0.63 D to 0.44+/-0.24 D (P<.001). Mean percent reduction of astigmatism was 90.4+/-5.0% (range 80% to 100%). Mean spherical equivalent refraction decreased from -2.19+/-0.88 D (range -1.00 to -3.88 D) to -0.32+/-0.34 D (range -1.25 to +0.38 D) (P<.001). Vector analysis showed that the mean amount of axis deviation was 0.7+/-1.2 degrees (range 0 degrees to 4.3 degrees) and the mean percent correction of preoperative astigmatism was 92.1+/-5.9% (range 85.6% to 108%). Eighty-five percent of all eyes had a mean spherical equivalent refraction and mean cylinder within +/-0.50 D of emmetropia. Change in spherical equivalent refraction and cylinder from 2 weeks to 6 months was < or = 0.50 D in 90% (18 eyes) and 95% (19 eyes), respectively. Spectacle-corrected visual acuity was not reduced in any eye. Diffuse lamellar keratitis occurred in three eyes (15%) after LASIK, and were treated successfully with eyedrops. CONCLUSION: LASIK was an effective, predictable, stable, and safe procedure for correction of residual myopic or mixed astigmatism ranging from 3.00 to 6.00 D with a low spherical component after cataract surgery.     

Simple regression formula for intraocular lens power adjustment in eyes requiring cataract surgery after excimer laser photoablation

PURPOSE: To develop a simple and accurate method for determining appropriate intraocular lens (IOL) power in cataract patients who had prior excimer laser photoablation for myopia or hyperopia, because laser vision corrective surgery interferes with traditional keratometry and corneal topography, rendering IOL power calculations inaccurate. SETTING: Private Practice in Century City (Los Angeles), California, and free-standing outpatient surgery centers with institutional review boards. METHODS: Based on the empiric experience of the senior author, an IOL power correction factor that was proportional to the prior laser photoablation was determined and applied to the IOL power calculated by the IOLMaster (Zeiss). It was necessary to add to the predicted IOL power in eyes with prior myopic laser ablation, whereas eyes having prior hyperopic laser vision correction required a reduction in the IOL power. The correction factor was applied to 30 eyes that required cataract surgery at some time after laser refractive surgery; 23 eyes had prior treatment for myopia, and the remaining 7 eyes had prior hyperopic laser ablation. A regression formula was generated from the IOL power correction factor that was used in the 30 eyes. RESULTS: Using the correction factor for 30 eyes, the mean deviation from the desired postcataract refractive outcome was -0.15 diopter (D) +/- 0.29 (SD); 28 of 30 eyes were within +/-0.5 D of the intended goal; the remaining 2 eyes were both -0.75 D from the desired optical result of cataract surgery. Fourteen of the 30 eyes were emmetropic. CONCLUSIONS: A simple IOL power corrective adjustment regression formula allowed accurate determination of IOL power after laser refractive photoablation surgery. The weakness of the current method is that knowledge of the amount of prior laser vision correction is necessary.     

Analysis of intraocular lens power calculation for eyes with previous myopic LASIK

PURPOSE: To evaluate the effectiveness of a manual keratometry (K) adjusted value for intraocular lens (IOL) power calculation in patients who underwent cataract surgery following previous myopic LASIK. METHODS: Sixteen eyes of 14 consecutive patients who underwent cataract surgery after previous LASIK were evaluated retrospectively. All IOL powers were calculated using an adjusted K value (K minus 1.0 diopter [D]) with the Binkhorst II formula aiming for -0.75 to -1.00 D final refraction. Additionally, the IOL power for each eye was retrospectively calculated using K, refractive-derived K, and adjusted K with the Binkhorst II, Holladay I, and SRK/T formulas. The final refraction was used as a criterion of accuracy of each approach. RESULTS: Uncorrected visual acuity > or = 20/40 was achieved in 14 (87.5%) of 16 eyes. The mean postoperative spherical equivalent refraction was -0.41 +/- 0.57 D (range: +0.50 to -2.00 D). Twelve (75%) of 16 eyes were within +/- 0.50 D of emmetropia and 15 (94%) of 16 eyes were within +/- 1.00 D. No eye was > +1.00 D. CONCLUSIONS: Using an adjusted K with the Binkhorst II formula, aiming for -0.75 to -1.00 D, and with the Holladay I formula, aiming for -0.50 to -1.00 D, measuring K with a regular manual keratometer permits determination of an IOL power after myopic LASIK without the need of preoperative LASIK refractive data.     

Prospective evaluation of intraocular lens calculation after myopic refractive surgery

PURPOSE: To evaluate outcome after refractive surgery in cataract patients for whom intraocular lens (IOL) selection was based on the use of a myopic regression formula. METHODS: This prospective case series included 20 eyes of 14 patients who had previous uncomplicated myopic refractive surgery, followed by uncomplicated cataract extraction with IOL implantation. Calculation of IOL was based on flattest keratometry readings, spherical equivalent refraction before refractive surgery, and an adjustment factor derived from the regression formula: -(0.47x + 0.85). Following cataract extraction, refractive error was compared against refractive aim. The power of IOL obtained by the regression formula (IOL(RF)) was compared to those obtained using the clinical history method at the spectacle plane (IOL(HisKs)) and the Double-K formula (LOL(DoubleK)). The results acquired with each technique were compared with those achieved using an IOL back-calculated for emmetropia (IOL(exact)). RESULTS: Using the regression formula, IOL calculations produced postoperative cataract extraction refractions within 1.00 diopter (D) (range: -1.00 to 0.78 D) of the intended outcome. Mean spherical equivalent refraction after cataract extraction was -0.31 +/- 0.56 D. Twelve of 20 eyes had sufficient data to evaluate the statistical relationships among the three formulas compared with IOL(exact). Paired t test results revealed IOL(RF) (P = .0932) and IOL(HisKs) (P = .9955) were not statistically different from IOL(exact) whereas IOL(DoubleK) was statistically different from IOL(exact) (P = .0008). CONCLUSIONS: The myopic regression formula is recommended for postoperative myopic LASIK IOL selection to provide a simple, accurate, and consistent method of predicting IOL calculation that is not statistically different from IOL(exact).     

Piggyback intraocular lens implantation to correct myopic pseudophakic refractive error after penetrating keratoplasty

PURPOSE: To determine the safety and efficacy of implanting a second intraocular lens (IOL) to correct myopic pseudophakic refractive error after penetrating keratoplasty (PKP). SETTING: Department of Ophthalmology, Toronto Western Hospital, Toronto, Ontario, Canada. METHODS: In this retrospective case series, 6 eyes of 6 post-PKP pseudophakic patients had a second piggyback IOL implantation to correct a residual myopic refractive error. The uncorrected visual acuity (UCVA) and the best corrected visual acuity (BCVA) were measured at regular intervals during a 7-month follow-up. Efficacy was determined by the achieved refractive correction and Snellen UCVA measurements. Safety was measured by loss of BCVA and complications (intraoperative and postoperative). RESULTS: The UCVA improved in all cases. Five patients achieved a BCVA of 20/40 or better postoperatively. Before surgery, the mean spherical equivalent (SE) was -8.08 diopters (D) (range -6.13 to -12.00 D). After surgery, the mean SE was -0.94 D (range -2.38 to +0.25 D). Four patients were within +/-1.50 D of emmetropia. There were no intraoperative or postoperative complications. CONCLUSION: Implanting a piggyback IOL was a safe and effective means of correcting myopic pseudophakic refractive error post PKP.     

A comparative analysis of intraocular lens power calculation methods after myopic excimer laser surgery

PURPOSE: To compare the accuracy and predictability of different intraocular lens (IOL) power calculation methods in eyes after myopic excimer laser surgery. METHODS: Phacoemulsification and IOL implantation outcomes in 37 eyes of 37 patients with prior LASIK or photorefractive keratectomy were documented (amount of correction=-6.92+/-3.12 diopters (D), range: -2.00 to -13.00 D). The theoretical IOL power that would have resulted in emmetropia was calculated (IOLemme). Using the clinical history keratometry and biometry, the IOL power was calculated using the following methods: Sanders, Retzlaff, Kraff (SRK)-T, SRK-T Double-K (DK), Holladay 1 DK, Hoffer Q DK, Holladay 2 DK, Feiz-Mannis, and Ladas-Stark corneal bypass. The calculated IOL power was compared to IOLemme and used to determine the mean error and mean absolute error of refractive outcome for each eye. RESULTS: The calculated IOL power using the SRK-T, Feiz-Mannis, and Holladay 1 DK methods were significantly different from IOLemme. The lowest mean absolute error was achieved using the Hoffer Q DK method (0.75+/-0.52 D), Holladay 2 DK (0.75+/-0.62 D), SRK-T DK (0.76+/-0.60 D), and Ladas-Stark (0.83+/-63 D). With the SRK-T DK method, 51.4% of eyes were within +/-0.50 D of emmetropia and 67.6% of eyes were within +/-1.00 D. The Holladay 2 DK method had the highest percentage (81.1%) of eyes within +/-1.00 D and 45.9% within +/-0.50 D. CONCLUSIONS: The refractive results of IOL implantation using the same biometry data in eyes after LASIK can vary markedly. The SRK-T DK, Hoffer Q DK, and Holladay 2 DK methods resulted in the highest accuracy.     

Refractive results with secondary piggyback implantation to correct pseudophakic refractive errors

PURPOSE: To assess the efficacy and safety of implanting a second intraocular lens (IOL) to correct pseudophakic refractive errors. SETTING: Goldschleger Eye Institute, Sheba Medical Center, Tel Hashomer, Israel. METHODS: This prospective noncomparative case series included 10 pseudophakic eyes, 5 with a myopic residual refractive error and 5 with a hyperopic residual refractive error. All eyes had secondary piggyback IOL implantation with the IOL placed in the ciliary sulcus. Five types of IOLs were used to correct the residual refractive error. RESULTS: The mean preoperative myopia was -6.6 diopters +/- 3.3 (SD), and the refractive outcome was within 0.5 +/- 0.7 D of the desired refraction (range -1.5 [undercorrected] and +1.0 D [overcorrected]). The mean preoperative hyperopia was +3.8 +/- 0.8 D, and the refractive outcome was within 0.46 +/- 0.4 D of the desired refraction (range 0 and 1.0 D overcorrected). All patients showed visual acuity improvement. Best spectacle-corrected visual acuity improved from 20/44 to 20/30 (P<.05). CONCLUSION: An IOL type that is appropriate for implantation in the ciliary sulcus is a viable option for correcting pseudophakic refractive error using the piggyback technique.     

Intraocular lens calculations after refractive surgery

PURPOSE: To evaluate the effect of refractive surgery on intraocular lens (IOL) power calculation, compare methods of IOL power calculation after refractive surgery, evaluate the effect of pre-refractive surgery refractive error on IOL deviation, review the literature on determining IOL power after refractive surgery, and introduce a formula for IOL calculation for use after refractive surgery for myopia. SETTING: Laser & Corneal Surgery Associates and Center for Ocular Tear Film Disorders, New York, New York, USA. METHODS: This retrospective noncomparative case series comprised 21 patients who had uneventful cataract extraction and IOL implantation after previous uneventful myopic refractive surgery. Six methods of IOL calculation were used: clinical history (IOL(HisK)), clinical history at the spectacle plane (IOL(HisKs)), vertex (IOL(vertex)), back-calculated (IOL(BC)), calculation based on average keratometry (IOL(avgK)), and calculation based on flattest keratometry (IOL(flatK)). Each method result was compared to an "exact" IOL (IOL(exact)) that would have resulted in emmetropia and then compared to the pre-refractive surgery manifest refraction using linear regression. The paired t test was used to determine statistical significance. RESULTS: The IOL(HisKs) was the most accurate method for IOL calculations, with a mean deviation from emmetropia of -0.56 diopter +/-1.59 (D), followed by the IOL(BC) (+1.06 +/- 1.51 D), IOL(vertex) (+1.51 +/- 1.95 D), IOL(flatK) (-1.72 +/- 2.19 D), IOL(HisK) (-1.76 +/- 1.76 D), and IOL(avgK) (-2.32 +/- 2.36 D). There was no statistical difference between IOL(HisKs) and IOL(exact) in myopic eyes. The power of IOL(flatK) would be inaccurate by -(0.47x+0.85), where x is the pre-refractive surgery myopic SE (SEQ(m)). Thus, without adjusting IOL(flatK), most patients would be left hyperopic. However, when IOL(flatK) is adjusted with this formula, it would not be statistically different from IOL(exact). CONCLUSIONS: For IOL power selection in previously myopic patients, a predictive formula to calculate IOL power based only on the pre-refractive surgery SEQ(m) and current flattest keratometry readings was not statistically different from IOL(exact). The IOL(HisKs), which was also not statistically different from IOL(exact), requires pre-refractive surgery keratometry readings that are often not available to the cataract surgeon.     

Laser in situ keratomileusis to correct residual myopia after cataract surgery

PURPOSE: To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) for correcting residual myopia after cataract surgery with intraocular lens implantation. METHODS: Twenty-two eyes of 22 patients underwent LASIK for the correction of residual myopia after cataract surgery. LASIK was carried out using the Chiron Automated Corneal Shaper and the NIDEK EC-5000 excimer laser. In all eyes, the follow-up was 12 months. RESULTS: Before LASIK, 1 eye (4.5%) had an uncorrected visual acuity of 0.5 or better; 12 months after LASIK, 10 eyes (45.4%) achieved this level of visual acuity and 0 eyes achieved 1.00 or better. Before LASIK, mean refraction was -2.90 +/- 1.80 D; 12 months after LASIK it decreased significantly to 0.40 +/- 0.60 D (P < .01). In 18 eyes (81.8%) at 12 months after LASIK, spherical equivalent refraction was within +/-1.00 D of emmetropia; 11 eyes (50%) were within 0.50 D. No vision-threatening complications occurred. CONCLUSION: LASIK with the Automated Corneal Shaper and Nidek EC-5000 excimer laser was an effective, predictable, stable, and safe procedure for correcting residual myopia after cataract surgery. No intraocular lens or cataract incision related complications occurred when LASIK was performed at least 3 months after phacoemulsification.     

Secondary piggyback implantation versus IOL exchange for symptomatic pseudophakic residual ametropia

Background

To evaluate the safety and efficacy of implanting a secondary IOL in comparison with IOL exchange to correct residual spherical refractive error after cataract surgery.

Method

This prospective case series included 23 pseudophakic eyes of 23 patients. They were divided into two groups: group I included 12 eyes for whom secondary piggyback IOL implantation in the ciliary sulcus was done, and group II included 11 eyes for whom IOL exchange was done. The mean follow up was 18?±?4.2 months and 20?±?3.6 months in groups I and II respectively. The visual and refractive outcomes were evaluated, and any intraoperative or postoperative complications was recorded.

Results

The mean spherical equivalent in group I (secondary piggyback implantation), was reduced from ?6.2?±?2.2 diopters preoperatively to ?0.28?±?0.59D postoperatively in myopic eyes and from 4.79?±?1.02D to 0.03?±?0.74D in hyperopic eyes. Ninety-two percent of eyes were within ±0.5D of intended correction. In group II (IOL exchange), the mean SE was reduced from ?5.88?±?3.1D preoperatively to 0.16?±?1.09 D postoperatively in myopic eyes and from 5.05?±?0.93D preoperatively to 0.11?±?0.69D postoperatively in hyperopic eyes. Eighty-two percent of eyes had postoperative SE within?±?0.5D of the intended correction. UCVA improved significantly in both groups. Rupture of the posterior capsule occurred in one eye in group II. Only one eye in group II lost one line of BCVA.

Conclusion

Secondary piggyback implantation in the ciliary sulcus is an effective, safe, and easy treatment for a pseudophakic ametropia.     

Accuracy and predictability of intraocular lens power calculation after laser in situ keratomileusis

PURPOSE: To study the accuracy and predictability of intraocular lens (IOL) power calculation in eyes that had laser in situ keratomileusis (LASIK). SETTING: Gimbel Eye Centre, Calgary, Alberta, Canada. METHODS: Refractive outcomes in 6 cataract surgery and lensectomy eyes after previous LASIK were analyzed retrospectively. Target refractions based on measured and refraction-derived keratometric values were compared with postoperative achieved refractions. Differences between target refractions calculated using 5 IOL formulas and 2 A-constants and achieved refractions were also compared. RESULTS: The refractive error of IOL power calculation in postoperative LASIK eyes was significantly reduced when refraction-derived keratometric values were used for IOL power calculation. Persistent residual hyperopia still occurred in some cases; this was corrected by hyperopic LASIK. Refractive results appeared more accurate and predictable when the Holladay 2 or Binkhorst 2 formula was used for IOL power calculation. CONCLUSION: Hyperopic error after cataract surgery in post-LASIK eyes was significantly reduced by using refraction-derived keratometric values for IOL power calculation. Persistent hyperopic error was corrected by hyperopic LASIK.     

角膜屈光矫正手术后白内障手术

目的:探讨角膜屈光矫正手术后白内障手术的诊疗特点。方法:对2005/2008年间于我院就诊的4例角膜屈光矫正手术后白内障患者行白内障超声乳化吸出术+人工晶状体植入术。依据患者提供的角膜屈光手术资料,分别采用临床病史法或角膜后表面曲率法计算矫正角膜曲率及人工晶状体度数。术后随访观察角膜情况、手术并发症、裸眼视力、最佳矫正视力、术后屈光状态等。结果:术后最佳矫正视力较术前明显提高。术后稳定屈光度与手术前预留屈光状态比较误差范围为-1.00～+1.25D。结论:对角膜屈光手术后的白内障患者施行白内障超声乳化吸出术+人工晶状体植入术是可行的。然而只有了解这类患者病情特点,掌握手术前后诊疗方法,准确计算人工晶状体度数,才能达到满意的疗效。     

Laser in situ keratomileusis and photorefractive keratectomy for residual refractive error after phakic intraocular lens implantation

PURPOSE: To determine the visual and refractive outcome of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) in eyes with prior posterior chamber phakic intraocular lens implantation for high myopia. METHODS: We studied a series of 37 consecutive eyes of 31 patients who underwent LASIK or PRK for residual refractive error following collamer posterior chamber intraocular lens (IOL) (Staar Surgical Implantable Contact Lens) implantation into a phakic eye. Twenty-eight eyes had LASIK and nine eyes had PRK. Mean follow-up was 8.1 +/- 4.7 months after laser ablation (range, 3 to 18 mo). RESULTS: The preoperative mean spherical equivalent refraction prior to phakic posterior chamber IOL implantation was -17.74 +/- 4.89 D (range, -9.75 to -28.00 D). Following phakic IOL implantation and prior to LASIK or PRK, mean spherical equivalent refraction was -2.56 +/- 2.34 D (range, -0.25 to -8.75 D). One month following LASIK or PRK, mean spherical equivalent refraction was -0.24 +/- 0.52 D (range, -1.50 to +1.50 D), 3 months following LASIK or PRK, mean spherical equivalent refraction was -0.19 +/- 0.50 D (range, -1.50 to +1.00 D). The refraction was within +/-1.00 D of emmetropia in 36 eyes (97.2%) and within +/-0.50 D in 31 eyes (83.7%). Three eyes developed anterior subcapsular opacities several weeks after laser ablation, one eye developed macular hemorrhage 4 weeks after laser ablation, and one eye had corticosteroid induced ocular hypertension. CONCLUSIONS: LASIK or PRK can be used to treat the residual refractive error following posterior chamber phakic IOL implantation.     

Results of laser in situ keratomileusis for myopia of -10 to -19 diopters with a Technolas 217 laser

PURPOSE: To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) for correcting myopia greater than -10.00 D. METHODS: Sixty-five eyes of 37 patients with myopia greater than -10.00 D underwent LASIK. Patients were evaluated on day 1, 1 week, 1, 3, and 6 months after surgery. Parameters evaluated were uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), residual refractive error, regression of correction, and presence of any complication. RESULTS: Mean preoperative BSCVA was 0.745 +/- 0.234, which improved to 0.8070 +/- 0.237 postoperatively. The average preoperative UCVA was 0.022 +/- 0.02; postoperative UCVA at 6 months was 0.536 +/- 0.255. UCVA of 20/40 or better was achieved in 58% (38 eyes) and 20/20 or better in 26% (17 eyes). The average refractive error before LASIK was -12.64 +/- 2.16 D (range -10.00 to -19.00 D). Mean residual refractive error 1 week following LASIK was -0.63 +/- 1.36 D, which regressed to a mean -1.78 +/- 2.08 D at the end of 6 months. Nineteen eyes (29%) were within +/-0.50 D of intended refractive correction. CONCLUSION: LASIK was partially effective in the correction of high myopia. An initial overcorrection may be programmed to offset the effect of refractive regression.     

LASIK for myopia with the Zeiss meditec MEL 80

PURPOSE: To prospectively evaluate a new high-speed, small spot-scanner laser for the correction of myopia and myopic astigmatism. METHODS: Seventy-six consecutive eyes with myopia and myopic astigmatism between -1.00 and -8.25 diopters (D) and up to -2.75 D astigmatism underwent LASIK treatment using the MEL 80 laser (Carl Zeiss Meditec, Jena, Germany). Parameters evaluated were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), residual refractive error, regression of correction, and aberrometry. RESULTS: Mean preoperative BSCVA was 20/20, which improved to 20/18 postoperatively. Postoperative UCVA was 20/20 at 1 month and 20/18 at 1 year. Uncorrected visual acuity > or = 20/20 was achieved in 58 (83%) of 70 eyes at 1 month and in 60 (88%) of 68 eyes at 1 year. The average refractive error before LASIK was -4.41 +/- 1.98 D. The mean residual refractive error was 0.14 +/- 0.31 D at 1 month and 0.13 +/- 0.30 D at 1 year. At 1-month and 1-year follow-up, respectively, 66 (94%) of 70 eyes and 65 (96%) of 68 eyes were within +/- 0.50 D of intended refractive correction. No eye lost two lines. At 1 month 17% of eyes and at 1 year 13% of eyes gained two lines or more. Between 1-month and 1-year follow-up, 100% of eyes were stable. Mean root-mean-square high order aberration changed from 0.20 microm preoperatively to 0.28 microm postoperatively. CONCLUSIONS: The MEL 80 is effective and safe in the treatment of myopia and myopic astigmatism.     

Off-axis refraction and aberrations following conventional laser in situ keratomileusis

PURPOSE: To investigate off-axis refraction and aberrations following conventional laser in situ keratomileusis (LASIK) for myopia and hypermetropia. SETTING: School of Optometry, Queensland University of Technology, Australia. METHODS: Using an autorefractor, off-axis refractions were analyzed along the horizontal visual field between 35 degrees nasally and 35 degrees temporally in 1 eye each of 15 emmetropic subjects (-0.50 to +0.50 diopters [D]), 6 myopic subjects (-2.25 to -6.50 D), 6 hyperopic subjects (+1.50 to +3.00 D), 6 myopic LASIK patients (presurgical refraction -2.75 to -9.00 D), and 6 hyperopic LASIK patients (presurgical refraction +0.75 to +2.00 D). Wavefront sensing measured off-axis higher-order aberrations in 2 myopic LASIK patients. RESULTS: In myopic LASIK, the mean spherical components of refraction M became highly myopic away from the center of the visual field; in emmetropic and untreated myopic eyes, there were relatively small myopic shifts and hyperopic shifts, respectively. Off-axis 90-degree to 180-degree astigmatisms J180 in myopic LASIK subjects were greater than in untreated subjects. In hyperopic LASIK, there were mainly hyperopic shifts in M, opposite the direction in emmetropic and untreated hyperopic subjects. Off-axis J180 was less than in emmetropic and untreated hyperopic subjects. Some hyperopic LASIK patients had greater off-axis 45-degree to 135-degree astigmatisms J45 than patients in the other groups. In 2 myopic LASIK patients, Zernike root-mean-square 4th-order aberrations were higher than in the near-emmetropia group because of higher levels of positive spherical aberration. CONCLUSIONS: Off-axis aberrations can be dramatically affected by conventional myopic and hyperopic LASIK. In myopic LASIK, the increased off-axis refractive errors may have adverse effects on peripheral visual tasks that are dependent on off-axis refractive errors. The relatively low off-axis refractive errors in hyperopic LASIK patients may improve peripheral visual tasks.     

Laser in situ keratomileusis for recurrent hyperopia following laser thermal keratoplasty

PURPOSE: Laser thermal keratoplasty (LTK) has its main indication in the correction of hyperopia. However, regression of refractive effect following LTK is a limitation. Laser in situ keratomileusis (LASIK) may provide a good alternative to correct residual refractive errors. METHODS: Fifty hyperopic eyes with varying amounts of regression after LTK underwent LASIK. The Chiron Automated Corneal Shaper microkeratome was used to make a flap of 160 microm and laser ablation was performed with the Technolas 217 Planoscan excimer laser. Postoperative follow-up was 6 months. RESULTS: Mean spherical equivalent refraction improved from +2.92+/-1.60 D to +0.36+/-1.48 D. Mean best spectacle-corrected visual acuity changed from 0.78+/-0.14 before LASIK to 0.76+/-0.16 D 6 months after LASIK. Mean uncorrected visual acuity changed from 0.37+/-0.16 to 0.66+/-0.24. Forty-two percent (21 eyes) were within +/-0.50 D of intended correction, 60% (30 eyes) were within +/-1.00 D, and 76% (38 eyes) were within +/-2.00 D. After LASIK, confluent haze between previous LTK spots was observed in most eyes, as LASIK ablation took place at the sites of the LTK spots. CONCLUSIONS: LASIK after LTK is a good alternative for hyperopic regression. Predictability and efficacy are less than with primary LASIK for hyperopia, but the procedure is equally safe.