Laser in situ keratomileusis for high myopia with the VISX star laser

Ocular Biometrics of Vietnamese Young Adults with Myopia

BACKGROUND:

Myopia is most prevalent type of refraction error. In some Asian countries, the prevalence of myopia can be 80 – 90% in the population aged 17 – 18.

AIM:

To analyze the correlation between ocular biometric indices and refraction status in Vietnamese young myopes.

METHODS:

A prospective cross – section study was conducted in young myopes. Data on axial length, central cornea thickness, corneal topography & anterior chamber depth and spherical equivalent were collected. Independent Sample T Test and ANOVA test were used to compare between groups. The correlations between ocular biometry and myopic spherical equivalent refraction were examined by Pearson Correlation with the level of significance p < 0.05.

RESULTS:

Totally, 418 eyes from 209 patients were recruited. The average axial length, central cornea thickness, cornea refraction & anterior chamber depth were 25.68 ± 1.09 mm, 539.78 ± 32.665 µm, 43.16 ± 1.369 D, 3.30 ± 0.243 mm, respectively. The correlation between axial length and spherical equivalent refraction (SER) was high (r = - 0.742, p < 0.0001) while those between central cornea thickness and cornea refraction were negligible (r = - 0.107, p = 0.029; r = -0.123, p = 0.012; respectively). There was no correlation between anterior chamber depth and spherical equivalent refraction (r = 0.019, p = 0.697).

CONCLUSION:

Among ocular biometric indices, axial length was significantly correlated with spherical equivalent of young adult patients.

Overnight orthokeratology is comparable with atropine in controlling myopia

Background

Many efforts have been invested in slowing progression of myopia. Among the methods, atropine administration and orthokeratology (OK) are most widely used. This study analyzed the efficacy of atropine and OK lens in controlling myopia progression and elongation of axial length.

Methods

This retrospective study included 105 patients (210 eyes) who wore OK lenses and 105 patients (210 eyes) who applied 0.125% atropine every night during the 3 following period. Student t-test, linear regression analysis, repeated measure ANOVA, and Pearson’s correlation coefficient were used for statistical analysis.

Results

The change in axial length per year was 0.28 ± 0.08 mm, 0.30 ± 0.09 mm, and 0.27 ± 0.10 mm in the OK lens group, and 0.38 ± 0.09 mm, 0.37 ± 0.12 mm, and 0.36 ± 0.08 mm in the atropine group for years 1, 2, and 3, respectively. Linear regression analysis revealed an increase in myopia of 0.28 D and 0.34 D per year, and an increase in axial length of 0.28 mm and 0.37 mm per year in the OK lens and atropine groups, respectively. Repeated measure ANOVA showed significant differences in myopia (p = 0.001) and axial length (p < 0.001) between the atropine and OK lens groups; in astigmatism, there was no significant difference in these parameters (p = 0.320). Comparison of increases in axial length in relation to baseline myopia showed significant correlations both in the OK lens group (Pearson’s correlation coefficient, r = 0.259; p < 0.001) and atropine group (r = 0.169; p = 0.014). High myopia patients benefited more from both OK lenses and atropine than did low myopia patients. The correlation of baseline myopia and myopia progression was stronger in the OK lens group then in the atropine group.

Conclusions

OK lens is a useful method for controlling myopia progression even in high myopia patients.

Artiflex versus STAAR implantable contact lenses for correction of high myopia

Purpose:

To compare two phakic intraocular lenses, Artiflex and STAAR^® implantable contact lens (ICL), in high myopia.

Setting:

Isfahan Ophthalmology Clinic, Iran.

Materials and Methods:

In a randomized, prospective clinical trial study, 40 eyes of 20 patients who came to Isfahan ophthalmology clinic to correct their refractive error were examined. Artiflex was inserted in 20 eyes and ICL in the other 20 eyes. After 1 year, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), contrast sensitivity, intraocular pressure (IOP), and specular microscopy of corneal endothelium were assessed in both the groups.

Results:

In this study, there was no statistical difference between UCVA, BCVA, IOP, cataract incidence, contrast sensitivity, and specular microscopy, 1 year after surgery. 40% of eyes in the Artiflex group developed anterior chamber cell and flare reaction 1 year postoperatively, but no patient in the ICL group developed the same. So, there is obvious difference in the rate of anterior chamber cell and flare reaction between these two groups.

Conclusion:

These two lenses have similar outcomes except in the incidence rate of anterior chamber cell and flare reaction that is greater in the Artiflex group. So, these two lenses are safe with predictable outcome in treating high myopia.

Ten-year follow-up of laser in situ keratomileusis for high myopia

PURPOSE

To evaluate the long-term outcomes of laser in situ keratomileusis (LASIK) for high myopia.

DESIGN

A long-term (10 years) follow-up retrospective interventional case series study.

METHODS

The study included 196 myopic eyes of 118 patients with a mean preoperative spherical equivalent of -13.95 +/- 2.79 diopter (D) treated with myopic LASIK at the Instituto Oftalmológico de Alicante, Spain using the VISX 20/20 excimer laser (VISX Inc, Santa Monica, California, USA) and the Automated Corneal Shaper microkeratome (Chiron Vision, Irvine, California, USA). All patients were evaluated three months, one year, two years, five years, and 10 years postoperatively. The main outcome measures were refractive predictability and stability, mean corneal keratometry, topographical cylinder, safety, efficacy, stability of visual acuity, and postoperative complications.

RESULTS

At 10 years, 82 (42%) of 196 eyes were within +/-1.00 D and 119 (61%) were within +/-2.00 D. Fifty-four (27.5%) eyes underwent retreatments attributable to under correction and/or regression. The myopic regression decreases with time in eyes that did not undergo retreatment with a mean rate of -0.25 +/- 0.18 D per year. Eleven eyes (5%) lost more than 2 lines of best spectacle-corrected visual acuity (BSCVA) and 78 eyes (40%) showed a postoperatively uncorrected visual acuity of 20/40 or better. Two eyes (1%) with more than 15 D myopic correction developed corneal ectasia.

CONCLUSIONS

LASIK for myopia over -10 D is a safe procedure with myopic regression that slows down with time and a high rate of BSCVA increase in the long-term.

Retrospective comparison of 3 laser platforms to correct myopic spheres and spherocylinders using conventional and wavefront-guided treatments

PURPOSE

To compare 3 excimer laser platforms for the correction of myopic spheres and myopic spherocylinders using conventional algorithms or wavefront-guided treatments.

SETTING

Private practice, in-office laser facility.

METHODS

This retrospective comparative interventional case series comprised 458 patients (721 eyes). Sequentially selected patient eyes had laser in situ keratomileusis surgery by the same surgeon using 1 of 3 lasers (Visx Star S4, LADARVision 4000, WaveLight Allegretto) with a conventional algorithm or with wavefront-guided software. The same aberrometer was used before and after surgery in a given eye. A femtosecond laser (IntraLase Corp.) was used for flap creation. Parametric and nonparametric 1-way analysis of variance and regression analysis were performed. Outcomes were analyzed for change in visual, refractive, and wavefront categories.

RESULTS

On average, all lasers improved uncorrected visual acuity and best spectacle-corrected visual acuity, produced predictable refractive change, and induced higher-order aberrations (HOAs). Overall, the Star S4 wavefront treatment improved results compared with Star S4 conventional treatment; however, LADARVision wavefront treatment did not improve the conventional results. The Allegretto produced the best results in the category of visual acuity in spherocylinder eyes only. The Star S4 wavefront treatment produced the best HOA results for sphere and spherocylinder. In the spherocylinder group, the LADARVision reduced astigmatism and defocus the most.

CONCLUSION

These results document that different laser platforms achieve statistically significantly different outcomes depending on refractive, patient, and surgical variables.

Long-term results of laser in situ keratomileusis for high myopia: Risk for ectasia

PURPOSE

To ascertain the long-term stability of laser in situ keratomileusis (LASIK) in highly myopic eyes.

SETTING

Clinical practice office-based surgery.

METHOD

Charts of eyes with high myopia who had LASIK surgery by the same surgeon between 1994 and 2000 were reviewed in 2003, and patients were given an appointment for follow-up examinations. In these highly myopic eyes, surgery was originally performed to create undercorrections with or without decreasing the ablation diameters to maximally conserve the residual stromal bed thickness.

RESULTS

Of the 107 eyes with myopia between -10.00 diopters (D) and -35.00 D reviewed and operated on in a 3-year period between 1994 and 1998, 35 eyes of 31 patients had a single enhancement procedure. One case of ectasia as a result of excessive tissue removal occurred in a patient with a preoperative refraction of -28.00 D. Of the 107 eyes reviewed, 78 (73%) were examined after 5 years, 68 (63%) after 7 years, and 15 (14%) between 9 years and 11 years.

CONCLUSIONS

Operating on eyes with highly myopic refractive errors and removing substantial tissue thickness did not produce ectasia in this series. Although high myopia has been considered a risk factor for post-LASIK ectasia, adherence to proper screening and intraoperative pachymetry appears to decrease the risk.

Clinical Results With the Medennium Phakic Refractive Lens for the Correction of High Myopia

PURPOSE

To evaluate the predictability, safety, stability, complications, and biocompatibility of the phakic refractive lens (PRL) as a posterior chamber intraocular lens to correct high myopia.

METHODS

Fifty eyes of 31 patients who underwent posterior chamber PRL implantation were evaluated prospectively. Mean preoperative myopia was -12.54 +/- 4.22 diopters (D) (range: -4.50 to -23.50 D) and mean astigmatic refractive power was -1.38 +/- 1.24 D (range: -1.00 to -4.50 D). Surgical implantation was performed through a 3.0- to 4.0-mm clear cornea sutureless incision using parabulbar (sub-Tenon's) anesthesia. Intra- and postoperative complications were recorded.

RESULTS

Three months after surgery, the mean spherical equivalent refraction was -0.21 +/- 0.42 D (range: +1.00 to -1.75 D). At 6 and 12 months, mean spherical equivalent refraction was -0.23 +/- 0.38 D (range: 0 to -1.25 D). At the last examination, uncorrected visual acuity was > or = 20/40 in 41 (82%) eyes and > or = 20/20 in 22 (44%) eyes. Best spectacle-corrected visual acuity (BSCVA) was > or = 20/40 in 42 (84%) eyes and > or = 20/20 in 27 (54%) eyes. Comparison of pre- and postoperative BSCVA at 12 months showed that 12 (36.4%) of 33 eyes gained > or =1 lines of BSCVA and 7 (21.2%) of 33 eyes gained > or =2 lines. One (2%) eye developed anterior subcapsular cataract requiring lens exchange, and 1 (2%) eye developed acute angle closure glaucoma requiring YAG-iridotomy. One (2%) eye developed macular hemorrhage.

CONCLUSIONS

At 6 months and 1 and 2 years, PRL implantation yielded encouraging visual and refractive results with excellent biocompatibility. The efficacy, stability, and short-term safety of this lens was established. Serious complications, such as cataract and acute angle closure glaucoma, may occur, and long-term safety needs to be evaluated.

Simultaneous laser in situ keratomileusis on the stromal bed and undersurface of the flap in eyes with high myopia and thin corneas

PURPOSE

To evaluate simultaneous laser in situ keratomileusis (LASIK) on the stromal bed and the undersurface of the flap in eyes with high myopia and insufficient corneal thickness for conventional LASIK ablation.

SETTING

21 Century Eye Hospital, Seoul Paik Hospital, Inje University, Seoul, Korea.

METHODS

Using intraoperative pachymetry, the residual stromal bed thickness was evaluated and simultaneous LASIK was performed on the stromal bed and undersurface of the flap without compromising the posterior 300 mum of the stromal bed. In a prospective series, outcomes in 43 eyes of 27 patients with mean spherical equivalent refraction ranging from -12.5 to -3.75 diopters were analyzed 1, 3, and 6 months after surgery.

RESULTS

Postoperative uncorrected visual acuity was 20/30 or better in 35 eyes (81.4%) at 1 month, 36 eyes (83.7%) at 3 months, and 34 eyes (79.1%) at 6 months. During surgery and follow-up, no vision-threatening complications occurred.

CONCLUSION

Simultaneous LASIK appears to be a useful surgical aid in LASIK treatment in eyes with high myopia with or without astigmatism when an adequate residual stromal bed does not exist.

Laser in situ keratomileusis for different degrees of myopia

PURPOSE

To determine the efficacy, predictability, stability and safety of laser in situ keratomileusis (LASIK) in treating patients with different degrees of myopia.

METHODS

We enrolled 386 eyes of 200 consecutive patients who underwent LASIK and divided them into four groups according to their degree of preoperative spherical equivalent (SE). Group 1 eyes ranged between - 1.00 and - 3.99 dioptres (D) (low myopia). Group 2 eyes ranged between - 4.00 and - 5.99 D (moderate myopia). Group 3 eyes ranged between - 6.00 and - 9.99 D (high myopia). Group 4 eyes were over - 9.99 D (extreme myopia). Follow-up was at 1 day, 1 week and 1, 3, 6, 12 and 18 months postoperatively.

RESULTS

Our study included 386 eyes of 200 patients with SE ranging from - 3.00 to - 16.00 D (mean - 7.14 +/- 2.87 D). All eyes were seen at 1 day postoperatively. A total of 360 eyes (93%) were examined at 1 week, 330 eyes (85%) at 1 month, 281 eyes (73%) at 3 months, 247 eyes (64%) at 6 months, 199 eyes (52%) at 12 months and 142 eyes (37%) at 18 months. The postoperative data from 1 day to 12 months were used because of the low follow-up rate at 18 months postoperatively. Group 1 consisted of 30 eyes. The mean SE was - 3.52 +/- 0.43 D preoperatively and - 0.40 +/- 0.58 D at 1 month, - 0.46 +/- 0.60 D at 6 months and - 0.42 +/- 0.50 D at 12 months postoperatively. Uncorrected visual acuity (UCVA) was 20/40 or better in 95% of eyes at 1 day and in 100% of eyes at 6 and 12 months postoperatively. Group 2 consisted of 151 eyes. The mean SE was - 5.36 +/- 0.67 D preoperatively and - 0.54 +/- 0.78 D at 1 month, - 0.56 +/- 0.90 D at 6 months and - 0.55 +/- 0.82 D at 12 months postoperatively. Uncorrected VA was 20/40 or better in 95% of eyes at 1 day and in 100% of eyes at 6 and 12 months postoperatively. Group 3 consisted of 167 eyes. The mean SE was - 8.15 +/- 0.94 D preoperatively and - 0.58 +/- 0.90 D at 1 month, - 0.67 +/- 1.00 D at 6 months and - 0.64 +/- 0.95 D at 12 months postoperatively. Uncorrected VA was 20/40 or better in 90% of eyes at 1 day and in 98% of eyes at 6 and 12 months postoperatively. Group 4 consisted of 38 eyes. The mean SE was - 11.09 +/- 1.10 D preoperatively and - 1.25 +/- 1.20 D at 1 month, - 1.13 +/- 1.30 D at 6 months and - 1.20 +/- 1.25 D at 12 months postoperatively. Uncorrected VA was 20/40 or better in 78% of eyes at 1 day, in 94% at 6 months and in 90% at 12 months postoperatively. Intraoperative complications (free cap) occurred in two eyes and postoperative complications were observed in three eyes, making the total complications rate 1.29% (5/386). Seven eyes lost one Snellen line of BCVA, five lost two lines and two lost more than two lines (total: 3.64%, 14/386).

CONCLUSION

In conclusion, LASIK is effective, predictable and safe for correcting myopia but is more accurate for correcting myopia up to -10.00 D. With more improvement in algorithms and ablation profile, we believe that LASIK can offer better results for higher myopia.

Changes in contrast sensitivity after Artisan lens implantation for high myopia

PURPOSE

To determine the effects of Artisan lens implantation on contrast sensitivity.

DESIGN

Prospective consecutive interventional case series.

PARTICIPANTS AND CONTROLS

Forty-nine eyes of 30 patients with myopia and myopia with astigmatism, who underwent implantation of the Artisan iris-fixated phakic intraocular lens. Preoperative testing served as the control.

INTERVENTION

Implantation of the Artisan phakic intraocular lens to correct myopia.

MAIN OUTCOME MEASURES

Refractive predictability and Snellen visual acuity were evaluated preoperatively and at least 4 months postoperatively. Additionally, photopic and mesopic contrast sensitivities were measured at 1.5, 3, 6, 12, and 18 cycles per degree, with and without glare testing.

RESULTS

The mean preoperative spherical equivalent (SE) was -12.16 diopters (D) (range, -6.88 to -18.00). The mean postoperative SE was -0.46+/-0.58 D (range, +0.50 to -1.75). Ninety percent of eyes were within 1.00 D of the predicted result, and 39% gained > or =1 lines of best-corrected visual acuity (BCVA). When compared with preoperative measurements, postoperative contrast sensitivity was increased under photopic conditions and slightly decreased under mesopic conditions. Adverse events were one wound leak requiring resuturing in the immediate postoperative period and one subluxed lens after significant blunt trauma. No eyes lost > or =2 lines of BCVA.

CONCLUSIONS

Artisan implantation for the correction of high myopia seems to be a predictable procedure. Increases in photopic contrast sensitivity values after implantation of this phakic intraocular lens stand in distinction to the decreases in photopic contrast sensitivity previously reported after LASIK correction of this degree of myopia.

Combined ICRS insertion and LASIK to maximize postoperative residual bed thickness in high myopia

PURPOSE

To describe a new technique and early outcomes of combined intrastromal corneal ring segment (ICRS) insertion and laser in situ keratomileusis (LASIK) to treat patients with moderate to high myopia and thin corneas.

SETTING

University-based academic practice, Boston, Massachusetts, USA.

METHODS

Combined ICRS insertion and LASIK was performed in 2 stages: ICRS channel formation (stage I) followed by LASIK and ICRS insertion (stage II).

RESULTS

Fifteen eyes of 11 patients with a mean preoperative spherical equivalent of -9.98 diopters (D) +/- 2.60 (SD) (range -7.13 to -16.25 D) and mean preoperative astigmatism of 1.11 +/- 0.75 D (range 0.00 to -3.00 D) were treated with combined ICRS insertion and LASIK. The mean central pachymetry was 526.13 +/- 35.69 microm (472 to 579 microm). The uncorrected visual acuity was 20/40 or better in 7 of 15 eyes (46.67%) at 1 month, 6 of 12 eyes (50.00%) at 3 months, 5 of 12 eyes (41.67%) at 6 months, and 6 of 12 eyes (50.00%) at 12 months. The best spectacle-corrected visual acuity was 20/40 or better at all times. Postoperative maps confirmed the absence of ectasia. The postoperative spherical equivalent was within +/-1.00 D of the intended refraction in 11 of 15 eyes (73.33%) at 1 month, 9 of 12 eyes at 3 and 6 months, and 8 of 12 eyes (66.67%) at 12 months.

CONCLUSIONS

Results of combined ICRS insertion and LASIK in moderately to highly myopic patients with relatively thin corneas were good. Long-term studies are needed to determine whether this procedure will decrease the risk of LASIK-induced keratectasia in these patients.

The effect of corneal flap on optical aberrations

PURPOSE

To evaluate the changes in ocular aberrations induced by corneal flap creation.

DESIGN

Prospective interventional nonrandomized clinical trial.

METHODS

This study included 15 patients who were scheduled for laser in situ keratomileusis. A nasal hinge flap was created, using the Nidek MK-2000 microkeratome and then replaced without performing laser ablation. The ocular aberrations were measured before and after flap creation using the Nidek Optical Path Difference Scanning System ARK-10000.

RESULTS

The root mean square wavefront errors of the higher-order optical aberrations (third-, fourth-, fifth-, and sixth-order aberrations) were not significantly altered at 1 week postsurgery compared with the preoperative values (P >.35).

CONCLUSIONS

Creating a corneal flap with the Nidek MK-2000 microkeratome did not induce changes in higher-order optical aberrations as measured with the Nidek Optical Path Difference Scanning System ARK-10000 during the early postoperative period.

Infections following laser in situ keratomileusis: an integration of the published literature

Infections occurring after laser in situ keratomileusis (LASIK) surgery are uncommon, but the number of reports have steadily increased in recent years. This systematic, comprehensive review and analysis of the published literature has been performed in order to develop an integrative perspective on these infections. We have stratified the data by potential associations, microbiology, treatment, and the degree of visual loss, using Fisher's exact tests and Student's t-tests for analysis. In this review, we found that Gram-positive bacteria and mycobacterium were the most common causative organisms. Type of postoperative antibiotic and steroid use was not associated with particular infecting organisms or severity of visual loss. Gram-positive infections were more likely to present less than 7 days after LASIK, and they were associated with pain, discharge, epithelial defects, and anterior chamber reactions. Fungal infections were associated with redness and tearing on presentation. Mycobacterial infections were more likely to present 10 or more days after LASIK surgery. Moderate or severe visual reductions in visual acuity occurred in 49.4% of eyes. Severe reductions in visual acuity were significantly more associated with fungal infections. Flap lift and repositioning preformed within 3 days of symptom onset may be associated with better visual outcome.

Actual and theoretical risks for visual loss following use of the implantable contact lens for moderate to high myopia

PURPOSE

To estimate the actual and theoretical risks for visual loss associated with use of the implantable contact lens (ICL).

SETTING

Multicenter clinical trial data.

METHODS

An established model for estimating the risk for visual loss associated with retinal detachment (RD) following clear lens extraction (CLE) was modified to be applicable to the ICL. The risk for developing RD and the outcomes of RD surgery based on current lens extraction and RD repair techniques were updated. Non-RD-related risks for pseudophakia based on United States Food and Drug Administration (FDA) guidelines, actual visual loss data from the FDA ICL study, and calculated risks assuming a large future risk (10 times the current risk) of cataract development were also added.

RESULTS

The additional risk for visual loss due to cataract surgery is estimated at 0.19% and for subsequent RD assuming 10 times the current rate of cataract is 0.37%. Using an ultraconservative (high) model and adding the actual loss observed with the ICL, the total risk is 1.39%. The risk increases by 0.5% to 0.6% with each 10% increase in cataract incidence (eg, 10% to 20%, 20% to 30%). The risk for visual loss with CLE and/or laser in situ keratomileusis/photorefractive keratectomy in the same range of myopia is possibly 3.0% to 6.5%.

CONCLUSIONS

The ICL represents a viable alternative to currently available refractive procedures based on an analysis of the risk for visual loss.

Laser in situ keratomileusis and intrastromal corneal ring segments for high myopia. Three-step procedure

We describe a surgical procedure to correct relatively high myopia in patients with thin corneas. The technique combines laser in situ keratomileusis (LASIK) and intrastromal corneal ring segment (ICRS) implantation. The 3-step procedure comprises ICRS channel formation, LASIK, and segment insertion. The technique was used in 2 eyes of 2 patients with low pachymetry values and high myopia. One patient achieved an uncorrected visual acuity (UCVA) of 20/30 and a best spectacle-corrected visual acuity (BSCVA) of 20/25 with +0.50 -1.75 x 101. The other patient achieved a UCVA of 20/30 and a BSCVA of 20/20 with +0.75 -1.50 x 80.

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.

Management of myopic astigmatism with phakic intraocular lens implantation

A 48-year-old woman presented with a manifest refraction of -9.25 -2.25 x 98 that resulted in a best corrected visual acuity (BCVA) of 20/20(-2) in the right eye. She was contact lens intolerant but was not a good candidate for laser in situ keratomileusis because of a thin cornea. A phakic posterior chamber intraocular lens (IOL) with a toric optic was implanted with no operative complications. One day after surgery, the uncorrected visual acuity (UCVA) was 20/15. Five months postoperatively, the UCVA in the operated eye was 20/15 with a manifest refraction of +0.25 -0.25 x 60 and a BCVA of 20/15. No changes to the crystalline lens or anterior lens capsule were seen. This is the first report of implantation of a toric phakic IOL in North America.

Implantable contact lens for high myopia

PURPOSE

To evaluate the efficacy, safety, and biocompatibility of a collagen polymer implantable contact lens (ICL) (Staar Collamer) as a posterior chamber phakic intraocular lens (IOL) to correct high myopia.

SETTING

Departments of Ophthalmology, Helsinki University Central Hospital, Helsinki, and Tampere University Hospital, Tampere, Finland.

METHODS

A Staar Collamer posterior chamber phakic IOL was implanted in 38 eyes of 22 patients with a mean age of 39 years (range 24 to 54 years). The mean preoperative myopia was -15.10 diopters (D) (range -7.75 to -29.00 D). Surgical implantation was performed through a 3.0 mm clear corneal sutureless incision using paraocular anesthesia. The patients were followed clinically up to 3 years. The mean follow-up was 13.6 months (range 6 to 24 months) for refractive data and 22.3 months (range 6 to 35 months) for complications. The possible inflammatory response to the ICL was measured using a laser flare meter in 12 eyes.

RESULTS

Postoperatively, all eyes had a significant increase in uncorrected visual acuity, allowing all but 3 patients (5 eyes) to manage most activities without spectacles. The mean spherical equivalent refraction at the last examination was -2.00 D +/- 2.48 (SD) (range +0.13 to -13.00 D), within +/-1.00 D of the targeted refraction in 31 eyes (81.6%) and within +/-0.50 D in 27 eyes (71.1%). In eyes in which the preoperative myopia was less than -18.00 D (n = 28), the achieved refraction was within +/-1.00 D of the intended refraction in 27 eyes (96.4%) and within +/-0.50 D in 24 eyes (85.7%). The refraction remained stable with a statistically insignificant change (P >.05) at each interval during the follow-up. The best corrected visual acuity (BCVA) improved by 1 or more lines in 23 of 32 eyes (71.9%) at 1 year. Two eyes (6.3%) lost 1 line of BCVA. Laser flare photometry showed normal aqueous flare values (11.71 +/- 6.61 photon counts/ms) in the 12 eyes measured at least 6 months after ICL implantation. Pupillary block glaucoma requiring surgical intervention occurred in 3 patients (7.9%). One patient (2.6%) developed cataract 1.5 years after ICL implantation; both ICLs were removed, and the refractive errors were corrected by lensectomy and implantation of low-power posterior chamber IOLs. One patient (2.6%) showed progression of dry macular degeneration at 17 months.

CONCLUSION

At 1 year, ICL implantation had good visual and refractive results with excellent biocompatibility. Long-term follow-up is required to confirm that significant complications do not occur in most patients over time.

Laser in situ keratomileusis for myopia and astigmatism: safety and efficacy: a report by the American Academy of Ophthalmology

OBJECTIVE

This document describes laser in situ keratomileusis (LASIK) for myopia and astigmatism and examines the evidence to answer key questions about the efficacy and safety of the procedure.

METHODS

A literature search conducted for the years 1968 to 2000 retrieved 486 citations and an update search conducted in June 2001 yielded an additional 243 articles. The panel members reviewed 160 of these articles and selected 47 for the panel methodologist to review and rate according to the strength of evidence. A Level I rating is assigned to properly conducted, well-designed, randomized clinical trials; a Level II rating is assigned to well-designed cohort and case-control studies; and a Level III rating is assigned to case series and poorly designed prospective and retrospective studies, including case-control studies.

RESULTS

The assessment describes randomized controlled trials published in 1997 or later (Level I evidence) and more recent comparative and noncomparative case series (Level II and Level III evidence), focusing on results for safety and effectiveness. It is difficult to extrapolate results from these studies that are comparable to current practices with the most recent generation lasers because of the rapid evolution of LASIK technology and techniques. It is also difficult to compare studies because of variations in the range of preoperative myopia, follow-up periods, lasers, nomograms, microkeratomes and techniques, the time frame of the study, and the investigators' experience.

CONCLUSIONS

For low to moderate myopia, results from studies in the literature have shown that LASIK is effective and predictable in terms of obtaining very good to excellent uncorrected visual acuity and that it is safe in terms of minimal loss of visual acuity. For moderate to high myopia (>6.0 D), the results are more variable, given the wide range of preoperative myopia. The results are similar for treated eyes with mild to moderate degrees of astigmatism (<2.0 D). Serious adverse complications leading to significant permanent visual loss such as infections and corneal ectasia probably occur rarely in LASIK procedures; however, side effects such as dry eyes, night time starbursts, and reduced contrast sensitivity occur relatively frequently. There were insufficient data in prospective, comparative trials to describe the relative advantages and disadvantages of different lasers or nomograms.

Laser in situ keratomileusis with the VISX Star laser for myopia over -10.0 diopters

PURPOSE

To evaluate the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) for myopia over -10.00 diopters (D).

SETTING

The Eye Institute of Utah, Salt Lake City, Utah, USA.

METHODS

The prospective study included 332 eyes of 183 patients having LASIK with the VISX Star laser to correct myopia of -10.00 to -18.00 D. The eyes were divided into 3 groups according to the preoperative refraction: Group A (n = 208), -10.00 to -11.90 D; Group B (n = 94), -12.00 to -14.00 D; Group C (n = 30), -14.10 to -18.00 D. The mean follow-up was 12.0 months +/- 5.6 (SD) (range 6 to 37 months).

RESULTS

Overall, the mean spherical equivalent decreased 96%, from -11.69 +/- 1.46 D preoperatively to -0.37 +/- 0.80 D postoperatively. The mean astigmatism decreased 72%, from 1.66 +/- 1.22 D to 0.46 +/- 0.53 D. At the last visit, 84.0% of eyes were within +/-1.00 D of emmetropia and 96.4% were within +/-2.00 D. An overcorrection of more than +1.00 D was experienced by 1.8% of patients. The uncorrected visual acuity (UCVA) was 20/20 or better in 45.8% of eyes and 20/40 or better in 89.5%. Six eyes (1.8%) lost 2 or more lines of best corrected visual acuity; this included 1 eye in which iatrogenic keratectasia developed 18 months after LASIK retreatment. Retreatment was done in 37.0% of eyes at a mean of 6.3 +/- 5.3 months (3 to 32 months) after the initial treatment. At the last examination, 86.0% of eyes in Groups A and B and 70.0% in Group C were within +/-1.00 D of emmetropia. A significant difference was found between Groups A and C (P =.032). The UCVA was 20/20 in 52.0% of Group A eyes, 38.0% of Group B eyes, and 23.0% of Group C eyes. The difference between Groups A and C was significant (P =.001), but the difference between Groups A and B was not (P =.055).

CONCLUSIONS

In this study, LASIK was effective in correcting myopia up to -14.00 D. The efficacy, predictability, and safety were significantly less in eyes with myopia greater than -14.00 D.

Soft Contact Lenses for Irregular Astigmatism After Laser in situ Keratomileusis

PURPOSE

To investigate soft contact lenses for managing irregular astigmatism after laser in situ keratomileusis (LASIK). The prevailing notion has been that soft contacts conform to corneal surface irregularities and have a limited role for managing LASIK-induced irregular astigmatism.

METHODS

A 41-year-old man with bilateral central steep islands following LASIK had best spectacle-corrected visual acuity of 20/40(+1) in the right eye and 20/70+2 in the left eye, despite 20/20 acuity in each eye with rigid contact lenses. Three soft lenses made of etafilcon A (58% H2O) in different center thicknesses were placed sequentially on each eye. All lenses were -2.00 D sphere, in the flatter of the two available base curves. With each lens, corneal topography, spherical over-refraction, and the resulting visual acuity were recorded.

RESULTS

In all instances, corneal topography showed reduced surface irregularity although at least some irregularity still transmitted through the lenses. Each spherical over-refraction gave better visual acuity than the corresponding best spectacle-corrected visual acuity. The right eye achieved 20/20 with the thickest lens and spherical over-refraction. The left eye achieved 20/25 with the lens of intermediate thickness and spherical overrefraction. The patient reported functional vision and good comfort with these lenses.

CONCLUSIONS

Disposable soft contact lenses can modestly mask irregular astigmatism caused by excimer laser ablation.