Trapezoidal relaxing incision for post keratoplasty astigmatism.
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Abstract:
Eleven patients with high astigmatism after penetrating keratoplasty underwent a new form of relaxing keratotomy, the trapezoidal relaxing keratotomy, originally described by Ruiz. The average preoperative astigmatism was 7.89 diopters (range 4.25 to 12.50 diopters) with an average reduction in cylinder of 5.00 diopters (range 0-9.5 diopters). No complications were experienced.Keywords:
Astigmatism
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The results of correction of residual myopia by photorefraction keratectomy (PRK) (51 eyes) and laser specialized keratomileusis (LASIK) (36 eyes) after radial keratotomy (RK) are compared. The patients were observed for up to 12 months. After PRK, 7.3% patients developed late fleur of the cornea, evaluated by at least 2 points. The incidence of fleur directly depended on the value of residual myopia. After LASIK none of the patients developed such fleur. The best visual acuity (0.5 and higher without correction) was attained in 70.73% after PRK and RK, vs. 100% after LASIK. The results of photorefraction operations and severity of residual myopia after RK correlated. In residual myopia of up to -3 diopters the results of correction by PRK and LASIK were virtually the same. In residual myopia higher than -3 diopters, LASIK is preferable.
LASIK
Radial keratotomy
Astigmatism
Vision disorder
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Astigmatism
Cycloplegia
Attendance
Eye examination
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Purpose: To evaluate the long-term effect of photoastigmatic refractive keratectomy (PARK) on mild keratoconus. Setting: Laser Unit, Ein Tal Eye Center, Tel Aviv, Israel. Methods: Eight eyes of 6 patients with stable compound myopic astigmatism and topography features of keratoconus were treated with a VISX Twenty-Twenty excimer laser. The laser beam slit width ranged between 4.8 and 5.0 mm according to the degree of cylinder. Preoperative slitlamp examination did not reveal significant thinning, ectasia, or scarring. Astigmatism ranged between -2.00 and -7.50 diopters and follow-up, between 36 and 48 months. Results: In 7 of 8 eyes, uncorrected visual acuity (UCVA) before PARK ranged between 6/30 and finger counting. After PARK, it ranged between 6/9(-) and 6/15, and patients could manage in most of their daily activities without using spectacles. In 2 eyes, the final UCVA was 6/15(-) and 6/15. In 1 eye, treatment failed to improve UCVA and corneal topography revealed progression of the keratoconus. Conclusions: Photoastigmatic keratectomy was partially effective in eyes with mild stable keratoconus. However, the long-term results may be altered by progression of corneal thinning and ectatic disease. In addition to the mild nature of the keratoconus, this is a small series and further studies are needed to confirm these results.
Ectasia
Astigmatism
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To determine whether posterior capsule opacification (PCO) is extensive in eyes with myopia or long axial length when an intraocular lens (IOL) of low-power, zero-power, or minus-power, is implanted.Hayashi Eye Hospital, Fukuoka, Japan.Ninety eyes of 90 patients scheduled for phacoemulsification surgery were recruited. These consisted of 30 eyes with high (> or =-8 diopters [D]) myopia, 30 eyes with moderate (<-8 D and > or =-3 D) myopia, and 30 eyes with low (<-3 D) myopia. All eyes had implantation of an acrylic IOL-low-power, zero-power, or minus-power-with a sharp optic edge (AcrySof MA60BM or MA60MA, Alcon Surgical). The PCO in these eyes was measured using a Scheimpflug videophotography system (EAS-1000, Nidek) 1, 3, 6, 12, 18, and 24 months after surgery. Visual acuity and the incidence of neodymium:YAG (Nd:YAG) laser posterior capsulotomy were also examined.No significant difference was observed in the mean PCO value or in the Nd:YAG capsulotomy rate between the high myopia, moderate myopia, or low myopia groups throughout the follow-up period. There was also no significant correlation between PCO value and the actual spherical power or axial length of the eye. Furthermore, although mean visual acuity tended to be worse in proportion to the degree of myopia, the difference was not statistically significant.When an acrylic IOL of low-power, zero-power, or minus-power with a sharp optic edge was implanted, high myopia and long axial length were not associated with the degree of PCO.
Posterior Capsule Opacification
Lens capsule
Capsule
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To determine the prevalence of refractive errors in Segovia, Spain.A cohort of 569 subjects was randomly selected in a stratified manner according to gender and age in a cross-sectional, population-based epidemiologic study, the target population of which was urban residents aged 40 to 79 years. All participants underwent an ophthalmic examination that included measurement of visual acuity (VA) and refraction, tonometry, anterior segment biomicroscopy, funduscopy, optic nerve head photography, and visual field testing. Of those, 417 subjects were enrolled who met the inclusion criteria of a phakic right eye and VA over 20/40. The prevalence of spherical errors was assessed after calculating the spherical equivalent and defining myopia as -0.5 diopters (D) or less and hyperopia as +0.50 D or more. The prevalence of astigmatism over 0.50 D was evaluated in minus cylinder form.The estimated prevalences (95% confidence interval) of myopia, hyperopia, and astigmatism, in the population were 25.4% (21.5-29.8%) 43.6% (39-48.4%), and 53.5% (48.7-58.2%), respectively. No significant gender difference was found in the prevalence of any refractive errors. The prevalence of myopia or the mean value did not change significantly with age. The mean hyperopia and the mean astigmatism (p < 0.01 for both) and the prevalence increased with increasing age (p < 0.01 for both). Anisometropia of 1 D or more was present in 12.3% (49/396 subjects).More than 60% of the Segovia population over 40 years of age has a refractive error, with 25.4% myopic and 43.6% hyperopic. Astigmatism is present in over half of the population and the types change with age.
Astigmatism
Anisometropia
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Astigmatism
Subjective refraction
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Twenty-three eyes of 22 patients remained undercorrected 5 to 49 months after radial keratotomy, either alone or in combination with transverse keratotomy.We attempted to correct the residual myopia ranging from -1.25 to -5.75 diopters (D) (with astigmatism of 0 to 1.25 D) with photorefractive keratectomy. The mean age of patients was 26 years (range 22 to 40 years).After photorefractive keratectomy (follow-up 6 to 17 months) uncorrected visual acuity was equal to or better than 20/20 in 39% (9 eyes), better than 20/25 in 65% (15 eyes), and better than 20/40 in 74% (17 eyes). Spectacle-corrected visual acuity was equal or better than 20/40 in all eyes; one eye (4%) lost two lines of spectacle-corrected visual acuity. Refractive error was within +/- 0.50 D in 48% (11 eyes) and within +/- 1.00 D in 65% (15 eyes). Undercorrections of more than 1.00 D occurred in 22% (5 eyes) and overcorrections of more than 1.00 D occurred in 13% (3 eyes). No or minimal haze was present in 57% (13 eyes), mild haze in 39% (9 eyes) and moderate haze in 4% (1 eye). Final uncorrected visual acuity was better (p = 0.0002) and haze was less (p = 0.003) in the group with less than -3.00 D than in the group with greater than or equal to -3.00 D.Photorefractive keratectomy after radial keratotomy is safe but less effective and less predictable in eyes with greater than or equal to -3.00 D compared to those with less than -3.00 D.
Radial keratotomy
Astigmatism
Vision disorder
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Purpose: To compare photorefractive keratectomy (PRK) with prophylactic use of mitomycin C (MMC) and LASIK in custom surgeries for myopic astigmatism. Methods: Eighty-eight eyes of 44 patients with a minimum estimated ablation depth of 50 µm were randomized to receive PRK with MMC 0.002% for 1 minute in one eye and LASIK in the fellow eye. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, slit-lamp microscopy, contrast sensitivity, specular microscopy, aberrometry, and a subjective questionnaire were evaluated. Forty-two patients completed 6-month follow-up. Results: Mean spherical equivalent refraction error before surgery and mean ablation depth were −3.99±1.20 diopters (D) and 73.09±14.55 µm in LASIK eyes, and −3.85±1.12 D and 70.7±14.07 µm in PRK with MMC eyes, respectively. Uncorrected visual acuity was significantly better in PRK with MMC eyes 3 months ( P =.04) and 6 months ( P =.01) after surgery. Best spectacle-corrected visual acuity and spherical equivalent refraction did not differ significantly in the groups during follow-up ( P >.05). Significant haze was not observed in any PRK with MMC eye. Mean higher order aberration was lower in PRK with MMC eyes postoperatively compared with LASIK eyes ( P =.01). Better contrast sensitivity was observed in PRK with MMC eyes than LASIK eyes ( P <.05). The endothelial cell count did not differ significantly between groups ( P =.65). In terms of visual satisfaction, PRK with MMC eyes were better rated. Conclusions: Photorefractive keratectomy with MMC appears to be more effective than LASIK in custom surgery for moderate myopia. During 6-month follow-up, no toxic effects of MMC were evident. Long-term follow-up is necessary to attest its safety. [ J Refract Surg . 2008;24:326–336.]
LASIK
Mitomycin C
Astigmatism
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To evaluate topography-guided photorefractive keratectomy (PRK) for correcting hyperopia and astigmatism after radial keratotomy (RK).Prospective study of 12 consecutive patients (19 eyes) who were treated with topography-guided PRK with 0.02% mitomycin C using an Asclepion-Meditec MEL-70 excimer laser with a 9.5-mm ablation zone. All eyes were operated by the same surgeon and followed for 1 year.Thirteen eyes had complete epithelialization by day 7 and all eyes by day 10. At 1 year, uncorrected visual acuity was 20/25 or better in 42.1% of eyes and 20/40 or better in 68.4%. Preoperative mean spherical equivalent refraction was +3.80+/-2.47 diopters (D) and +0.24+/-2.36 D (P<.001) 1 year postoperative, with 47.4% of eyes being within +/-1.00 D and 73.7% within +/-2.00 D. Preoperative mean cylinder was -2.30+/-1.41 D and -0.62+/-0.73 D (P<.001) 1 year postoperative. At 1 year, 68.4% of eyes gained at least 1 line of best-spectacle corrected visual acuity, 36.8% gained more than 1 line, and only 2 eyes lost 1 line (one due to corneal haze). Three eyes developed central haze. Mean regression from 6 to 12 months in these 3 eyes was +1.83 D and in the remaining 16 eyes was -0.50 D.Topography-guided PRK with mitomycin C was safe and reasonably effective for the treatment of hyperopia after RK.
Radial keratotomy
Astigmatism
Mitomycin C
Excimer
Vision disorder
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