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M C Knorz

Publications and source records attributed to M C Knorz.

At least 19 recordsLinked to original sources
PubMed2006

[Complications of refractive excimer laser surgery].

In surface ablation, haze is the most frequent complication. After LASIK, microkeratome-related complications are rare today and usually resolve without sequelae, provided no ablation was done. Postoperative flap complications such as flap slippage usually occur during the first few days after surgery and should be treated as early whenever present. Interface complications are a new diagnostic entity as the interface between flap and stroma presents a space where fluid or cells can accumulate. Diffuse lamellar keratitis usually occurs within the first few postoperative days and should be treated aggressively to avoid scarring. Epithelial ingrowth is another rare complication usually requiring treatment. Corneal hydrops with fluid accumulation in the interface is a very rare but important phenomenon related to steroid-induced glaucoma but presenting with false low tonometry readings. Corneal ectasia is extremely rare and in most cases related to thin stromal beds. However, its pathogenesis is not yet completely understood, and it may occur in "normal" eyes, too. Dry eye syndrome is the most frequent complication after LASIK. It is usually benign but may cause significant visual impairment in rare cases.

Corneal Diseases↗
PubMed2001

[Results of implantation of a Worst Iris Claw Lens for correction of high myopia].

BACKGROUND: The purpose of this clinical study was to evaluate refraction, best visual acuity and anterior chamber flare after implantation of a Worst Iris Claw Lens to correct high myopia. PATIENTS AND METHODS: From September 1996 to February 1999 the implantation of a Worst Iris Claw lens was performed on 44 highly myopic phakic eyes of 28 patients. Data after 6 weeks and 6 months follow-up were assessed. RESULTS: The mean preoperative spherical equivalent was--17.35 +/- 3.57 dpt and 6 months after implantation 79% of the eyes were within +/- 1.0 dpt of target refraction. The mean best corrected visual acuity increased from 0.43 preoperatively to 0.65 postoperatively and 6 months after the treatment there was no flare (< 10 photons/ms) in 21% and a mild anterior chamber flare (10-80 photons/ms) in 76% of the treated eyes. The median laser flare was 20 p/ms. CONCLUSIONS: In conclusion, implantation of a Worst Iris Claw lens has proved to be a precise method to correct high myopia. No or mild anterior chamber flare and a good visual acuity were measured in most eyes 6 weeks and 6 months after surgery. Longer follow-up periods are needed to assess the long-term safety and efficiency.

Follow-Up Studies↗
PubMed2001

[Virtual reality in ophthalmological education].

We present a computer-based medical training workstation for the simulation of intraocular eye surgery. The surgeon manipulates two original instruments inside a mechanical model of the eye. The instrument positions are tracked by CCD cameras and monitored by a PC which renders the scenery using a computer-graphic model of the eye and the instruments. The simulator incorporates a model of the operation table, a mechanical eye, three CCD cameras for the position tracking, the stereo display, and a computer. The three cameras are mounted under the operation table from where they can observe the interior of the mechanical eye. Using small markers the cameras recognize the instruments and the eye. Their position and orientation in space is determined by stereoscopic back projection. The simulation runs with more than 20 frames per second and provides a realistic impression of the surgery. It includes the cold light source which can be moved inside the eye and the shadow of the instruments on the retina which is important for navigational purposes.

Computer Graphics↗
PubMed2000

Delayed anterior ischemic optic neuropathy after neck dissection.

There are only 2 published cases of anterior ischemic optic neuropathy (AION) occurring after neck dissection, to our knowledge. We report a case of bilateral AION following neck dissection, discuss the differential diagnoses, and compare the features of this case with those of previously described cases. There were none of the previously described risk factors for the development of AION after head and neck surgery (eg, hypotension, facial edema, or sudden massive hemorrhage) in this case, but there was prolonged diffuse postoperative bleeding. Also, the symptoms did not arise before the fifth postoperative day as they did in the other cases. Prolonged, mild postoperative bleeding is a risk factor for AION. Visual loss during the entire first postoperative week has to be regarded as a complication of surgery, requires the exclusion of several differential diagnoses, and must not be confounded with the patient's confusion or symptoms of withdrawal.

Adult↗
PubMed2000

[Correction of myopia and astigmatism using topography-assisted laser in situ keratomileusis (TopoLink LASIK)].

PATIENTS AND METHODS: We treated 114 patients (eyes) with myopia of -1 to 6 D and astigmatism of 0 to -4 D (group 1), and 89 patients (eyes) with myopia of -6.1 to -12 D and astigmatism of 0 to -4 D (group 2). All treatments were calculated on the basis of corneal topography measured with the Orbscan II system. The Keracor 217 excimer laser and the Hansatome microkeratome were used. RESULTS: At 3 months, 51 patients in the low myopia group and 40 patients in the high myopia group were available for examination. In the low (high) myopia group, 96.1% (75.0%) were within +/- 0.50 D of emmetropia, and uncorrected visual acuity was 20/20 or better in 82.4% (62.5%), 20/25 or better in 98.0% (70.0%), and 20/40 or better in 100% (95.0%). A loss of two or more lines of spectacle-corrected visual acuity occurred in 3.9% of the low and 5.0% of the high myopia group. In low myopia, spectacle-corrected visual acuity was 20/12.5 or better in 5.9% preoperatively and in 13.7% at three months and 20/15 or better in 37.3% and 47.1%, respectively (P = 0.0002 and P = 0.01). CONCLUSIONS: LASIK based on corneal topography showed very high efficacy in low and moderate myopia with astigmatism, and maximal visual acuity could even be improved in some cases. There was somewhat less precision in high myopia with astigmatism.

Astigmatism↗
PubMed2000

Topographically-guided laser in situ keratomileusis to treat corneal irregularities.

OBJECTIVE: To evaluate the predictability and safety of topographically guided laser in situ keratomileusis (LASIK) to treat corneal irregularities. DESIGN: Prospective, noncomparative interventional case series. PARTICIPANTS: Twenty-seven patients (29 eyes) with postsurgical corneal irregularities, divided into four subgroups (postkeratoplasty, 6 eyes; posttrauma, 6 eyes; postphotorefractive keratectomy (PRK)/LASIK with decentered or small ablations, 11 eyes; post-PRK/LASIK with central islands, 6 eyes). INTERVENTION: LASIK was performed using the Automatic Corneal Shaper and the Keracor 117 C spot-scanning excimer laser (Bausch & Lomb Surgical Technolas, Munich, Germany). Individual ablation patterns were calculated on the basis of axial radii of curvature data obtained with the Corneal Analysis System (EyeSys Premier, Irvine, CA). MAIN OUTCOME MEASURES: Change of corneal topography pattern, patient satisfaction, manifest spectacle refraction, and visual acuity at 12 months after surgery. RESULTS: Corneal topography showed improved corneal regularity in 66% of eyes in the postkeratoplasty group, whereas 34% remained irregular. In the posttrauma group, 83% improved and 17% remained irregular. In the decentered/small optical zone group, 91 % improved and 9% remained irregular. In the central islands group, 50% improved and 50% remained irregular. Refractive cylinder decreased from 5.83 +/- 1.25 diopters (D) to 2.96 +/- 1.23 D in the postkeratoplasty group (P = 0.01), from 2.21 +/- 1.35 D to 0.50 +/- 0.84 D in the posttrauma group (P = 0.001), from 0.73 +/- 0.71 D to 0.36 +/- 1.05 D in the decentered/small optical zone group (NS), and from 1.42 +/- 1.13 D to 0.50 +/- 0.84 D in the central island group (P = 0.01). Uncorrected visual acuity improved from 20/200 +/- 0.07 to 20/50 +/- 0.17 in the postkeratoplasty group (P = 0.01), from 20/83 +/- 0.12 to 20/50 +/- 0.28 in the posttrauma group (P = 0.01), from 20/60 +/- 0.16 to 20/50 +/- 0.29 in the decentered/small optical zone group (NS), and from 20/71 +/- 0.12 to 20/60 +/- 0.24 in the central island group (NS). CONCLUSIONS: The topographically-guided LASIK method used in this study resulted in a significant reduction of refractive cylinder, a significant increase of uncorrected visual acuity, and improved corneal regularity in a large percentage of patients with severe corneal irregularities such as decentered/small optical zones after LASIK or irregular astigmatism after keratoplasty or trauma. With small irregularities such as central islands, results were sufficiently poor to advise against the use of our technique in these patients.

Adolescent↗
PubMed2000

Treatment of myopia and myopic astigmatism by customized laser in situ keratomileusis based on corneal topography.

OBJECTIVE: To evaluate the predictability, efficacy, and safety of customized laser in situ keratomileusis (LASIK) based on corneal topography in myopia and myopic astigmatism. DESIGN: Prospective, noncomparative interventional case series. PARTICIPANTS: One hundred fourteen patients (eyes) with myopia of -1 to -6 diopters (D) and astigmatism of 0 to -4 D (low myopia group), and 89 patients (eyes) with myopia of -6.10 to -12.00 D and astigmatism of 0 to -4.00 D (high myopia group). INTERVENTION: LASIK was performed with the Hansatome Microkeratome and the Keracor 217 spot-scanning excimer laser (Bausch & Lomb Surgical Technolas, Munich, Germany). Individual ablation patterns were calculated on the basis of elevation data obtained with the Orbscan II corneal topography system (Bausch & Lomb Surgical, Irvine, CA). MAIN OUTCOME MEASURES: Manifest spectacle refraction, visual acuity, and change in visual acuity at 3 months after surgery. RESULTS: At 3 months, 51 patients in the low myopia group and 40 patients in the high myopia group were available. In the low (high) myopia group, 96.1% (75.0%) were within +/-0.50 D of emmetropia, and uncorrected visual acuity was 20/20 or better in 82.4% (62.5%), 20/25 or better in 98.0% (70.0%), and 20/40 or better in 100% (95.0%). A loss of two or more lines of spectacle-corrected visual acuity occurred in 3.9% of the low and 5. 0% of the high myopia group. In low myopia, spectacle-corrected visual acuity was 20/12.5 or better in 5.9% preoperatively and in 13.7% at 3 months and 20/15 or better in 37.3% and 47.1%, respectively. Differences were statistically significant. CONCLUSIONS: The customized LASIK based on corneal topography used in this study showed high predictability and efficacy in myopia and myopic astigmatism of -1.00 to -6.00 D, and could possibly improve spectacle-corrected visual acuity in myopia of -1.00 to -6.00 D. Predictability and efficacy were somewhat lower in myopia and myopic astigmatism of -6.10 to -12.00 D. In both groups, a small number of patients lost two or more lines of spectacle-corrected visual acuity.

Astigmatism↗
PubMed2000

Cataract extraction with multifocal intraocular lens implantation: clinical, functional, and quality-of-life outcomes. Multicenter clinical trial in Germany and Austria.

PURPOSE: To compare bilateral implantation of a multifocal intraocular lens (IOL) versus a monofocal lens with respect to visual function, patient satisfaction, and quality of life. SETTING: Seven clinical sites in Germany and 1 site in Austria. METHODS: A prospective randomized masked clinical trial included 124 randomly assigned bilateral pseudophakic individuals, 64 of whom had bilateral implantation of an Array(R) foldable multifocal IOL (model SA-40N, Allergan) and 60 of whom had bilateral implantation of an AMO(R)PhacoFlex II(R) silicone monofocal IOL (model SI-40NB). Clinical data included binocular uncorrected and corrected distance and near visual acuities, complications, adverse events, and reports of halos and glare. Quality-of-life data were collected on 3 occasions using the modified Cataract TyPE Specification instrument. The functional status of the 2 groups was compared from baseline to final postoperative interview. RESULTS: Three months after surgery, a higher proportion in the Array group achieved a Jaeger value of J3 (20/40 Snellen) or better uncorrected binocular near visual acuity and 0.5 (20/40) or better distance-corrected binocular near visual acuity than in the monofocal groups (97% versus 68% and 95% versus 59%, respectively; P <.001). A higher proportion in the multifocal group achieved both 0.5 (20/40) and J3 or better uncorrected binocular distance and near visual acuities (97% versus 66%; P <.001). Those in the Array group were more likely than those in the monofocal group to never wear glasses overall (41% versus 12%; P <.001). Multifocal patients rated their vision without glasses better overall, at near and at intermediate distances (P <.05), and demonstrated better visual function for near tasks and social activities. CONCLUSIONS: Those who had bilateral implantation of the Array multifocal IOL obtained better uncorrected and distance-corrected near visual acuities and reported better overall vision, less limitation in visual function, and less spectacle dependency than patients with bilateral monofocal IOLs.

Aged↗
PubMed2000

TopoLink LASIK.

Explore the source record for details and available documents.

Astigmatism↗
PubMed1999

[Complications of laser in situ keratomileusis (LASIK)].

BACKGROUND: The incidence and course of intraoperative and postoperative complications of LASIK were investigated. PATIENTS AND METHODS: We consecutively treated 598 eyes (316 patients) using the Automatic Corneal Shaper and the Keracor 117 C excimer laser. One hundred and sixty-three eyes were also available at 12 months. The preoperative spherical equivalent was -5.31 +/- 5.49 D (+9 to -23 D). We evaluated intra- and postoperative complications. RESULTS: Intraoperative complications of keratotomy were observed in 1.3% (irregular cut, n = 5; free cap, n = 2; incomplete cap, n = 1), and other intraoperative complications in 1.7% (epithelial defects, n = 7; flap dislocation, n = 1; lateral kanthotomy required, n = 2). None of these complications caused any long-term effects or loss of two or more lines of visual acuity. Postoperative complications were observed in 0.9% (peripheral epithelial ingrowth, n = 4; keratectasia, n = 1; subretinal neovascularisation, n = 1). CONCLUSIONS: The rate of complications in LASIK is low, and intraoperative complications did not cause any significant loss of vision. We observed keratectasia in one eye, which suggests that deep ablations should be avoided, which limits the amount of correction possible.

Adolescent↗
PubMed1999

[Twilight visual acuity after correction of myopia with LASIK].

BACKGROUND: Data on mesopic vision after LASIK are not available to date. We therefore evaluated mesopic vision in myopic eyes before and after LASIK. PATIENTS AND METHODS: Sixty-seven eyes (34 patients) treated using the Automatic Corneal Shaper and the Keracor 117CT spot-scanning excimer laser were included. All eyes had best-corrected vision of 20/25 or better preoperatively. We measured spectacle refraction, visual acuity, and mesopic vision without and with glare (Nyktometer, Rodenstock) both preoperatively and 1 year after LASIK. Results were evaluated in three groups with reference to baseline refraction, and numbers of patients who saw a contrast of 1:5 or less were compared. RESULTS: Myopia -1 to -5 D (group 1; n = 26): Preoperatively (postoperatively), 89% (96%) (P = 0.03) of eyes identified a contrast of 1:5 or less without glare, while 65% (73%) achieved that level with glare. Myopia -5.1 to -10 D (group 2; n = 24): Preoperatively (postoperatively), 83% (75%) of eyes identified a contrast of 1:5 or less without glare, while 50% (21%) achieved that level with glare. Myopia -10.1 to -15 D (group 3; n = 11): Preoperatively (postoperatively), 73% (55%) of eyes identified a contrast of 1:5 or less without glare, while 46% (27%) achieved that level with glare. CONCLUSIONS: LASIK seems to cause a reduction of mesopic vision under glare conditions in corrections of more than -5 D. In corrections of more than -10 D, mesopic vision without glare is reduced, too. However, differences were not statistically significant when comparing vision at contrasts of 1:5 and lower. In addition, mesopic is considerably reduced in high myopes even preoperatively.

Adult↗
PubMed1998

[LASIK for myopia correction. 2-year follow-up].

BACKGROUND: Long-term results on LASIK are not available to date. We therefore evaluated the predictability, stability and complication rate after LASIK in moderate--to-high myopia. PATIENTS AND METHODS: We treated 70 eyes (41 patients) using the Automatic Corneal Shaper and the Keracor 116 excimer laser. Patients were followed for 1, 6, 12 and 24 months. Spectacle refraction, visual acuity, rate of retreatment, and patient satisfaction were evaluated. RESULTS: At 24 months the results were as follows: Myopia -5 to -9.9 D (n = 18): 94% within 1 D; regression between 1 and 12 (12 and 24) months > 1 D in 6% (6%); uncorrected acuity 20/40 or better in 83%; no loss of 2 ore more lines of visual acuity; 89% highly satisfied. Myopia -10 to -14.9 D (n = 12): 88% within 1 D; regression between 1 and 12 (12 and 24) months > 1 D in 20% (0%); uncorrected acuity 20/40 or better in 72%; 4% lost 2 or more lines of visual acuity; 96% highly satisfied. Myopia -15 to -29 D (n = 22): 33% within 1 D; regression between 1 and 12 (12 and 24) months > 1 D in 41% (18%); uncorrected acuity 20/40 or better in 7%; no loss of 2 or more lines of visual acuity; 67% highly satisfied. CONCLUSION: LASIK is an accurate, effective and stable procedure for correcting myopia of -5 to -10 D. Results are less precise in myopia up to -15 D, and some visual loss occurs in a number of patients. In myopia > -15 D, results are not satisfactory because of poor accuracy and low stability.

Adult↗
PubMed1998

Laser in situ keratomileusis for moderate and high myopia and myopic astigmatism.

OBJECTIVE: This study evaluated the predictability, stability, and safety of laser in situ keratomileusis (LASIK) in myopia and myopic astigmatism. DESIGN: The study design was a prospective, unmasked, nonrandomized clinical trial. PARTICIPANTS: Participating were 25 patients with myopia (37 eyes) with astigmatism of less than 1.00 diopter (D), divided into 3 subgroups (-5.00 to -9.90 D, 8 eyes; -10.00 to -14.90 D, 10 eyes; -15.00 to -29.00 D, 19 eyes), and 37 patients with myopia (56 eyes) with corneal astigmatism of 1.00 to 4.50 D, divided into 3 subgroups (-5.00 to -9.90 D, 12 eyes; -10.00 to -14.90 D, 24 eyes; -15.00 to -29.00 D, 20 eyes). INTERVENTION: LASIK was performed using the Automatic Corneal Shaper and the Keracor 116 excimer laser. MAIN OUTCOME MEASURES: Visual acuity, manifest refraction, central corneal islands, ablation decentration, and patient satisfaction were measured. RESULTS: At 12 months, predictability, regression between 1 and 12 months, uncorrected visual acuity (UCVA), loss of two or more lines of corrected visual acuity, and patient satisfaction of the spherical (toric) groups are reported. Subgroups -5.00 to -9.90 D: 100% (75%) +1.00 D; regression less than or equal to 1.00 D in 100% (91.7%); UCVA greater than or equal to 20/40 in 87.5% (70%); none lost two or more lines; 100% (84%) highly satisfied. Subgroups -10.00 to -14.90 D: 60% (78.3%) +/-1.00 D; regression less than or equal to 1.00 D in 100% (87%); UCVA greater than or equal to 20/40 in 77.8% (86.4%); 10% (4.3%) lost two lines; 90% (91%) highly satisfied. Subgroups -15.00 to -29.00 D: 38.9% (21.4%) +/-1.00 D; regression less than or equal to 1.00 D in 72.2% (64.3%); UCVA greater than or equal to 20/40 in 33.3% (40%); 5.6% (7.1%) lost two lines; 78% (50%) highly satisfied. Differences of predictability and change of manifest refraction between subgroups of -5.00 to -9.90 D and -15.00 to -29.00 D were statistically significant. Central islands (decentrations) were observed in 17% (5.6%) of eyes of the spherical and in 16% (4.1%) of the toric group. Overall, the corneal interface was visible in 8.2%. CONCLUSIONS: The LASIK method used in this study showed stability of manifest refraction and adequate uncorrected central visual acuity in a large percentage of patients with myopia up to -15.00 D. Corneal stability was not as uniform. Central corneal islands were observed in a sizable minority of patients despite pretreatment. For myopia greater than 15.00 D, accuracy and patient satisfaction were sufficiently poor to advise against using the authors' treatment technique in these groups. Visually significant microkeratome and laser-related problems were noted in a smaller percentage of patients. Patients with astigmatism correction were less pleased with results than were patients who received spherical corrections.

Adolescent↗
PubMed1998

Laser in situ keratomileusis assisted by corneal topography.

PURPOSE: To assess whether laser in situ keratomileusis (LASIK) assisted by corneal topography can successfully treat corneal irregularities or irregular astigmatism in patients with previous ocular surgery or ocular trauma. SETTING: University Eye Hospital, Klinikum Mannheim, Mannheim, Germany. METHODS: In a prospective clinical study, LASIK was performed in 23 eyes of 22 patients. Reasons for surgery were irregular astigmatism after penetrating keratoplasty or penetrating injury or corneal irregularity after previous excimer laser surgery. Excimer ablation was based on preoperative corneal topography data (Corneal Analysis System, EyeSys Technologies) using a proprietary algorithm (Topographic Assist LASIK, Chiron Vision). Follow-up was 6 months. RESULTS: Mean preoperative uncorrected visual acuity (UCVA) was 20/80 and mean best spectacle-corrected visual acuity (BSCVA), 20/35. Uncorrected visual acuity improved in all but two cases. Postoperatively, mean UCVA increased to 20/50; mean BSCVA was unchanged. No eye lost two or more lines of BSCVA. Postoperative topography showed less corneal irregularity in 81.3% of eyes; full correction was achieved in 19.4%. Four eyes (19.4%) needed re-treatment for undercorrection and three eyes (14.3%) for regression. CONCLUSION: Preliminary results indicate that the concept of topographic-assisted LASIK is feasible. However, most eyes were undercorrected and had regression. One reason might be that corneal topography underestimated corneal irregularity, causing significant undercorrection.

Adolescent↗
PubMed1997

Basic, not acidic fibroblast growth factor stimulates proliferation of cultured human retinal pigment epithelial cells.

PURPOSE: In this study, we evaluated a possible effect of acidic and basic fibroblast growth factor (aFGF, bFGF) on the proliferation of human retinal pigment epithelial (RPE) cells in culture. As the RPE is the primary source for bFGF in the retina, such an effect would suggest autocrinic actions of FGFs. METHODS: Primary cultures of human and porcine RPE and an established human RPE cell line (D407) were subjected to aFGF and bFGF at different culture conditions. Cell proliferation was determined using the BrdU non-radioactive nucleotide analogue assay, and total protein was measured colorimetrically. The cells were subjected to aFGF and bFGF from 0.1 to 100 ng/ml for 1 to 14 days. RESULTS: In the presence of 100 ng/ml bFGF, cell proliferation doubled from day 2 (143+/-12 units) to day 6 (227+/-17). This effect was neither seen without bFGF nor with aFGF at the same concentration. The stimulating effect of bFGF on cell proliferation was dose-dependent, the ED50 being around 1-10 ng/ml. The bFGF effect was markedly greater at high fetal calf serum concentration (10% vs. 1%). No bFGF effect was seen on cells of the established human RPE cell line D407 nor on primary cultures from porcine RPE. CONCLUSIONS: bFGF, in contrast to its analogue aFGF, stimulates cell proliferation in cultured human RPE cells. It may act as an autocrinic agent (secretion by and action on the same cell) and thus be a specific regulator for cell proliferation in repair and replacement of the RPE cell monolayer.

Animals↗
PubMed1997

[Laser in situ keratomileusis (LASIK) for correction of myopia].

BACKGROUND: Laser in situ keratomileusis (LASIK) preserves the corneal epithelium and Bowman's layer, which theoretically minimizes corneal scarring. We, therefore, evaluated the accuracy, stability and safety of LASIK in moderate to high myopia. PATIENTS AND METHODS: Eighty-five eyes (50 patients) treated using the Automatic Corneal Shaper and the Keracor 116 excimer laser were followed up for 1, 6, and 12 months. Spectacle refraction, visual acuity and rate of retreatments were evaluated. RESULTS: At 12 months, results were as follows: Myopia -5 to -9.9 D (n = 20); 85% within 1 D; regression between one and 12 months < or = 1 D in 90%; uncorrected acuity 20/40 or better in 75%; no loss of two or more lines of visual acuity. Myopia -10 to -14.9 D (n = 33): 73% within 1 D; regression between 1 and 12 months < or = 1 D in 91%; uncorrected acuity 20/40 or better in 79%; 6.1% lost two lines of visual acuity. Myopia -15 to -29 D (n = 32): 31% within 1 D; regression between one and 12 months < or = 1 D in 63%; 6.3% lost two or more lines of visual acuity. Reoperations were performed in two eyes (2.4%) due to epithelial ingrowth or folds of the flap, and in four eyes (4.7%) because of undercorrections or "central islands". CONCLUSIONS: LASIK is an accurate and stable procedure for correcting myopia of -5 to -15 D. In higher myopia, however, results are not satisfactory.

Adult↗
PubMed1996

[Correction of myopia using laser in situ keratomileusis (LASIK)].

BACKGROUND: In contrast to photorefractive keratectomy (PRK), the corneal epithelium and Bowman's layer are preserved in LASIK. Thus, there should be less scarring and regression after LASIK than after PRK. PATIENTS: Between December 1993 and October 1995, we treated 113 eyes (66 patients). The Automated Corneal Shaper and the Keracor 116 excimer laser were used. We evaluated refraction, visual acuity and corneal topography. RESULTS: To date, 61 eyes reached six months follow up. Mean preoperative refraction was -14.3 D (-3.3 to -29 D; SD = 7). Mean deviation from target refraction was -1.4 D (-9.5 to +2.5 D; SD = 2.7) at six months. 34% were within +/-0.5 D of target refraction, 46% within +/-1 D, 67% within +/-2 D, and 82% within +/-3 D. Mean change of refraction ("regression") from one to six months postoperatively was +0.13 D (-7.5 to +8 D; SD = 2.1). Refractive change was < 0.5 D in 51%, < 1 D in 66%, < 2 D in 84%, and < 3 D in 89%. In 88% of eyes, the corneal interface was not or just barely visible, while it was clearly visible in 12%. No scars were observed. CONCLUSIONS: Our results indicate that LASIK is an effective procedure in the correction of high myopia. The incidence of scar formation and regression is considerably lower than after PRK.

Adolescent↗