1/9. Topography-controlled excimer laser photorefractive keratectomy.PURPOSE: To assess whether photorefractive keratectomy (PRK) controlled by videokeratography can successfully treat refractive errors in eyes with corneal irregularities and improve spectacle-corrected visual acuity. methods: In a prospective clinical study, PRK was performed in 10 eyes of 10 patients. Reason for surgery was irregular astigmatism after penetrating keratoplasty, corneal irregularity after corneal scarring, corneal astigmatism in keratoconus, and decentration after myopic and hyperopic PRK. Excimer ablation was controlled by preoperative videokeratography (Orbscan II, Orbtek) using the MEL-70 system from Aesculap Meditec. Follow-up was 6 months. RESULTS: Concerning manifest refraction, the sphere was reduced on average from 1.92 to 0.57 D, 6 months postoperatively. Cylinder changed from -1.95 D on average to -0.30 D at 6 months postoperatively. There was improvement of uncorrected visual acuity of 2 or more lines in 5 eyes and no change in 5 eyes 6 months postoperatively. Spectacle-corrected visual acuity improved in 2 eyes by 2 to 3 lines, in 9 eyes by 1 to 3 lines, and showed no change in 1 eye. CONCLUSION: Videokeratography-controlled PRK improved refractive errors in irregular corneas with improvement of spectacle-corrected visual acuity.- - - - - - - - - - ranking = 1keywords = refractive error, error (Clic here for more details about this article) |
2/9. Effectiveness of LASIK to correct refractive error after penetrating keratoplasty.OBJECTIVE: refractive errors may invalidate the good results of penetrating keratoplasty (PK). The Authors evaluate the effectiveness of excimer laser in situ keratomileusis (LASIK) in the correction of refractive error after PK. MATERIALS AND methods: Four patients, a 26-year-old woman, a 54-year-old man, a 19-year-old man, and a 51-year-old woman, showed refractive errors: -11 = -4.5 x 85 ; -8, -4.5 = -11 x 95 ; and -4.5 = -4 x = 1200, with a clear graft at least 20 months after penetrating keratoplasty secondary to keratoconus. However, they underwent the LASIK procedure with a nasal-hinged flap of 160 um. No sutures were placed. RESULTS: At follow-up, 24, 18, 12, and 12 months, respectively, the graft remained clear and the endothelial cells were unchanged. The uncorrected visual acuities were 20/50, 20/25, 20/50, and 20/25, respectively with an unchanged best corrected visual acuity (20/20) for all patients. No significant complications were observed. CONCLUSIONS: LASIK procedure seems to be an effective technique to correct refractive error after successful penetrating keratoplasty.- - - - - - - - - - ranking = 3.5003816596629keywords = refractive error, error (Clic here for more details about this article) |
3/9. Implantation of Intacs and a refractive intraocular lens to correct keratoconus.We report a case of Intacs implantation for keratoconus followed by the implantation of an anterior chamber phakic refractive lens to correct a -8.25 diopter residual error.- - - - - - - - - - ranking = 0.0003816596629434keywords = error (Clic here for more details about this article) |
4/9. The use of the first locally manufactured epikeratolens for keratoconus in Leuven.We adapted a lathe to the production of keratolenses. A cornea is mounted on a chuck and frozen at minus 40 degrees C. Hereafter we can cut the desired posterior radius and diameter. The first plano keratolens produced was used to correct keratoconus. The favourable result encouraged us to manufacture keratolenses for the correction of refractive errors.- - - - - - - - - - ranking = 0.5keywords = refractive error, error (Clic here for more details about this article) |
5/9. Hyperopic photorefractive keratectomy with adjunctive topical mitomycin C for refractive error after penetrating keratoplasty for keratoconus.OBJECTIVE: To present a case of photorefractive keratectomy (PRK) with adjunctive topical mitomycin C (MMC) in an anisometropic hyperopic patient after penetrating keratoplasty (PKP) for keratoconus. methods: Interventional case report, chart review, and literature review. RESULTS: A 43-year-old man with a refraction of 7.00 -4.75 x 125 in the right eye underwent PRK 10 months after PKP for keratoconus. The patient had sutures removed for 3 months and was intolerant of contact lenses. After photoablation, 0.02% MMC was applied to the corneal stromal bed. The patient was followed up daily until the epithelium closed and at 1 week, 1 month, 3 months, and 6 months postoperatively. CONCLUSIONS: To our knowledge, this represents the first reported case of the use of MMC to prevent postoperative haze after PRK for PKP in an eye with keratoconus. MMC (0.02%) applied topically to the cornea immediately after PRK is safe and effective to treat a hyperopic refractive error after PKP and prevent postoperative corneal haze formation without the risks of performing a lamellar flap into an ectatic corneal bed.- - - - - - - - - - ranking = 2.5keywords = refractive error, error (Clic here for more details about this article) |
6/9. Wavefront aberrations associated with the Ferrara intrastromal corneal ring in a keratoconic eye.PURPOSE: To describe the optical implications of the aberration pattern of a keratoconic eye implanted with an intrastromal corneal ring (Ferrara ring). methods: A 32-year-old man with bilateral keratoconus had a Ferrara intrastromal corneal ring implanted in his right eye. Surgery was uneventful and both uncorrected (UCVA) and best spectacle-corrected (BSCVA) visual acuity improved. corneal topography was performed before and after surgery. Wavefront measurements were performed 1 month after the procedure in both eyes for comparison. The point spread function, modulation transfer function (MTF), and convolved acuity chart were analyzed. RESULTS: The right eye--implanted with the intrastromal Ferrara ring--had high root-mean-square (RMS) values for higher order aberrations. The left eye-keratoconus without an intrastromal ring-had moderate values. Point spread function, MTF, and convolution acuity charts are presented for each eye, with the latter two showing improved visual function in the implanted eye, despite a higher aberration value. CONCLUSION: The wavefront measurement device captured aberrations even in a highly aberrated eye. Despite better UCVA and BSCVA, the Ferrara ring notably increased higher order aberrations compared to the fellow eye, but with a more uniform central pattern. In this case, the larger RMS value was a poor predictor of good visual function; other metrics better predicted the patient's subjective response. Metrics other than RMS error may be necessary to better correlate aberration value with visual satisfaction in some eyes.- - - - - - - - - - ranking = 0.0003816596629434keywords = error (Clic here for more details about this article) |
7/9. Contact lens fitting in keratoconus.The treatment of keratoconus can be implemented by the use of spectacle lenses, contact lenses of various kinds, and surgery. In this article, we deal with the procedures of contact lens fitting in patients diagnosed with keratoconus. The different types of specific contact lenses and the methodology of fitting these contact lenses for keratoconus are described. To select a contact lens for the individual patient depends upon the severity of keratoconus and the amount of corneal ectasia. Pending these criteria, a contact lens is chosen, which will give the best visual acuity and tolerance. At present, many designs of special contact lenses exist in oxygen-permeable materials; in addition, other systems, such as piggy-back, SoftPerm, semi-scleral, and scleral contact lens types are used. Contact lens fitting on a conical cornea will smooth out the highly irregular optical surface of the cornea and improve visual acuity considerably. contact lenses are one of the better solutions to correct refractive errors induced by pathology, and they should be prescribed as soon as the keratoconus is detected to avoid development of amblyopia. The quality and quantity of vision is far better than with spectacle lens correction.- - - - - - - - - - ranking = 0.5keywords = refractive error, error (Clic here for more details about this article) |
8/9. Use of Verisyse iris-supported phakic intraocular lens for myopia in keratoconic patients.We report 2 patients with stable keratoconus and high myopia who benefited from implantation of an iris-supported phakic intraocular lens (Verisyse, AMO) for correction of their refractive error. Both patients had a postoperative uncorrected visual acuity of 20/40. Endothelial cell density showed at most a 4% decrease, and no evidence of keratoconus progression was witnessed. The use of the Verisyse lens may be beneficial for certain keratoconic patients as an alternative step between rigid gas-permeable lenses and penetrating keratoplasty.- - - - - - - - - - ranking = 0.5keywords = refractive error, error (Clic here for more details about this article) |
9/9. Potential complications of ocular surgery in patients with coexistent keratoconus and fuchs' endothelial dystrophy.PURPOSE: To describe the potential complications of cataract and refractive surgery in patients with fuchs' endothelial dystrophy (FED) and keratoconus. DESIGN: Retrospective case series. PARTICIPANTS: Eight patients with FED and keratoconus in a large university group practice. methods: We reviewed the clinical and topographic findings of 8 patients (15 eyes) with FED and keratoconus. Clinical examination, corneal topography, specular microscopy were done, and sequential central corneal thickness (CCT) was obtained. Follow-up ranged from 1 month to 6 years. MAIN OUTCOME MEASURES: Findings of keratoconus and FED in preoperative evaluation. RESULTS: Five patients had concomitant cataracts; 3 had refractive errors and sought surgical correction. Cataract surgery was performed on 3 of 5 patients (5 eyes). LASIK was performed on one eye of 3 patients. Of 5 eyes that underwent cataract extraction, 4 had blurry vision after surgery. The interval between the surgical procedure and onset of symptoms ranged from 1 month to 4 years. The causes of decreased vision after cataract surgery were corneal edema and/or corneal ectasia. The CCT readings ranged from 426 to 824 microm. One of 4 symptomatic eyes underwent penetrating keratoplasty. The CCTs of 3 patients (6 eyes) who presented with refractive error ranged from 507 to 565 microm. One eye had undergone an attempted LASIK procedure resulting in a lost cap. corneal topography and specular microscopy showed the coexistence of keratoconus and FED, and the patients were advised against having LASIK surgery. CONCLUSIONS: Corneal thinning caused by keratoconus and concurrent increase in corneal thickness caused by FED may combine to normalize the corneal pachymetry readings; disease severity may be underestimated, which may lead to unexpected postoperative visual outcomes. Routine use of preoperative topography and specular microscopy may help to avert potential surgical complications.- - - - - - - - - - ranking = 1keywords = refractive error, error (Clic here for more details about this article) |