[Results of implantation of a Worst Iris Claw Lens for correction of high myopia]. / Ergebnisse nach Implantation einer Worst Iris Claw Lens zur Korrektur der hohen Myopie.

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.

[Virtual reality in ophthalmological education]. / Virtuelle Realitäten für die augenchirurgische Ausbildung.

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.

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.

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

LASIK for hyperopia and hyperopic astigmatism--results of a pilot study.

Laser-assisted in situ keratomileusis (LASIK) was evaluated in hyperopia and hyperopic astigmatism. LASIK was safe and effective in spherical hyperopia up to +5 D and acceptable in toric hyperopia up to +5 D but results were poor in hyperopia of more than +5 D.

[LASIK for myopia correction. 2-year follow-up]. / LASIK zur Myopiekorrektur. 2-Jahres-Ergebnisse.

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.

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.