Intacs after laser in situ keratomileusis and photorefractive keratectomy

PURPOSE: To evaluate the efficacy of intrastromal corneal ring segments (Intacs, Addition Technology) for the correction of residual myopia after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). METHODS: In this prospective noncomparative case series, Intacs were implanted in 5 eyes (4 patients) that developed myopic regression after LASIK or PRK. Intacs were implanted a minimum of 11 months after the laser procedure. The technique was identical to the standard procedure for myopic unoperated eyes. The Intacs thickness was based on the amount of residual myopia. RESULTS: Postoperative results revealed a reduction in the residual myopia and the mean K-reading. No eye lost best corrected Snellen visual acuity. No intraoperative or postoperative complications occurred. CONCLUSIONS: Implantation of Intacs in eyes with myopic regression after LASIK and PRK resulted in a good refractive outcome and an improvement in uncorrected visual acuity.     

Photorefractive keratectomy or laser in situ keratomileusis for residual refractive error after phakic intraocular lens implantation

PURPOSE: To evaluate the results of combining phakic posterior chamber intraocular lens (IOL) implantation and excimer corneal surgery to treat high myopia or myopia with astigmatism. SETTING: Service d'Ophtalmologie, H?pital Purpan, University of Toulouse, Toulouse, France. METHODS: Thirty-two eyes of 28 patients with extreme myopia or myopia combined with astigmatism were treated by implantation of a phakic posterior chamber IOL. Residual refractive errors were treated no earlier than 6 weeks after IOL implantation by photorefractive keratectomy (PRK) in eyes with low refractive errors or by laser in situ keratomileusis (LASIK) in eyes with higher residual refractive errors. RESULTS: The mean preoperative spherical equivalent (SE) refraction was -18.7 diopters (D). The refractive astigmatism ranged from 0 to 3.5 D. After excimer laser treatment, the SE refraction ranged from -0.5 to -2.5 D and the refractive astigmatism, from 0 to 1.5 D in the PRK group. In the LASIK group, spherical ametropia ranged from -1.5 to +1.5 D and astigmatism, from 0 to 1.0 D. After excimer laser treatment, the uncorrected visual acuity improved in all eyes but a loss of 1 line of the corrected vision after IOL implantation occurred in 22.2% of PRK-treated eyes and in 13.6% of LASIK-treated eyes. CONCLUSIONS: Bioptic treatment of extreme myopia and myopia associated with astigmatism appears to be safer and more predictable than other methods of treatment.     

Artisan iris-claw phakic intraocular lens followed by laser in situ keratomileusis for high hyperopia

PURPOSE: To evaluate safety, efficacy, predictability, stability, complications, and patient satisfaction after Artisan phakic intraocular lens (IOL) implantation followed by laser in situ keratomileusis (LASIK) for the correction of high hyperopia. SETTING: Instituto Oftalmólogico de Alicante, Alicante, Spain. METHODS: This prospective trial included 39 eyes with a mean preoperative spherical equivalent (SE) of 7.39 diopters (D) +/- 1.30 (SD) and a cylinder between 0 and -4.25 D. The Artisan iris-fixated phakic IOL (Ophtec) for hyperopia was implanted, and LASIK was performed 6 to 8 months later. The best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), refraction, endothelial cell loss (ECL), endothelium morphologic analysis, and patient satisfaction were recorded. The minimum follow-up was 12 months. RESULTS: At 1 year, 37 eyes (94.9%) were within +/-1.00 D of emmetropia and 31 eyes (79.5%) were within +/-0.50 D. Thirty-five eyes (89.7%) achieved a UCVA of 0.5 or better. There was a statistically significant decrease in BCVA after phakic IOL implantation, but this effect was corrected after LASIK. Nine eyes (23.1%) lost 1 line of BCVA; 7 eyes (17.9%) gained at least 1 line. One eye (2.6%) showed a change in SE greater than 1.0 D over the follow-up period. The mean ECL was 10.9%, but morphologic analysis suggested no additional damage caused by LASIK over that produced by phakic IOL surgery. Overall patient satisfaction was high. CONCLUSIONS: The combination of Artisan phakic IOL implantation and LASIK safely, predictably, and effectively reduced high hyperopia. A loss of 1 line of BCVA should be expected in about one third of eyes implanted with this IOL. Halos and glare at night remain a potential problem.     

Laser in situ keratomileusis and photorefractive keratectomy for residual refractive error after phakic intraocular lens implantation

PURPOSE: To determine the visual and refractive outcome of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) in eyes with prior posterior chamber phakic intraocular lens implantation for high myopia. METHODS: We studied a series of 37 consecutive eyes of 31 patients who underwent LASIK or PRK for residual refractive error following collamer posterior chamber intraocular lens (IOL) (Staar Surgical Implantable Contact Lens) implantation into a phakic eye. Twenty-eight eyes had LASIK and nine eyes had PRK. Mean follow-up was 8.1 +/- 4.7 months after laser ablation (range, 3 to 18 mo). RESULTS: The preoperative mean spherical equivalent refraction prior to phakic posterior chamber IOL implantation was -17.74 +/- 4.89 D (range, -9.75 to -28.00 D). Following phakic IOL implantation and prior to LASIK or PRK, mean spherical equivalent refraction was -2.56 +/- 2.34 D (range, -0.25 to -8.75 D). One month following LASIK or PRK, mean spherical equivalent refraction was -0.24 +/- 0.52 D (range, -1.50 to +1.50 D), 3 months following LASIK or PRK, mean spherical equivalent refraction was -0.19 +/- 0.50 D (range, -1.50 to +1.00 D). The refraction was within +/-1.00 D of emmetropia in 36 eyes (97.2%) and within +/-0.50 D in 31 eyes (83.7%). Three eyes developed anterior subcapsular opacities several weeks after laser ablation, one eye developed macular hemorrhage 4 weeks after laser ablation, and one eye had corticosteroid induced ocular hypertension. CONCLUSIONS: LASIK or PRK can be used to treat the residual refractive error following posterior chamber phakic IOL implantation.     

Macular hole after laser in situ keratomileusis and photorefractive keratectomy

PURPOSE: To describe three myopic patients who developed unilateral macular hole after undergoing bilateral laser in situ keratomileusis or photorefractive keratectomy. METHODS: Case reports. RESULTS: Three eyes of three myopic patients developed a macular hole in one eye after bilateral laser in situ keratomileusis or photorefractive keratectomy. The macular hole formed between 4 to 7 weeks after laser in situ keratomileusis in case 1 (a 48-year-old woman), and within 2 months after laser in situ keratomileusis in case 2 (a 36-year-old woman). In case 3 (a 45-year-old man), the macular hole was found 9 months after photorefractive keratectomy. A vitrectomy closed the macular hole of case 1 with final best-corrected visual acuity of 20/25 and case 2 with 20/30, whereas case 3 declined further surgery. CONCLUSION: A macular hole may develop in myopic eyes after laser in situ keratomileusis or photorefractive keratectomy. Vitreoretinal interface changes may play a role.     

Ocular surface management of photorefractive keratectomy and laser in situ keratomileusis

PURPOSE: To examine the effects of keratorefractive surgery and ocular surface management on goblet cell density, dry eye symptom incidence, and spherical equivalent refraction. METHODS: We performed a retrospective analysis of four myopia groups: Untreated controls (n = 53); PRK (n = 51); LASIK without ocular surface management (n = 56); LASIK with ocular surface management (n = 140). Ocular surface management involved the routine use of non-preserved artificial tears and other lubricants before, during, and after surgery. Lid hygiene procedures, topical anti-inflammatory agents, and punctal plugs were used on indication. Assessments were conducted before and up to 12 months after surgery (right eyes only in patients with both eyes operated, and in the left or right eye in patients with one eye operated). RESULTS: Surgery caused a significant reduction in goblet cell density, with the greatest reduction in the LASIK without ocular surface management group. No significant differences were detected in dry eye symptoms or spherical equivalent refraction between PRK and LASIK without ocular surface management. Ocular surface management significantly minimized LASIK-induced decreases in goblet cell density and was associated with significantly less myopic outcomes at months 1 to 3 and 6 to 9 after LASIK. After surgery (1 to 3 mo), dry eye symptoms were significantly lower in the LASIK with ocular surface management group. In all groups, significant inverse correlations existed between goblet cell density and dry eye symptoms. CONCLUSIONS: Ocular surface management minimized the negative impact of LASIK on goblet cell density and reduced dry eye symptoms. Without ocular surface management, goblet cell density and dry eye symptoms after LASIK were similar to or worse than after PRK.     

Intraepithelial photorefractive keratectomy for regression after laser in situ keratomileusis.

PurposeTo propose a refractive procedure, intraepithelial photorefractive keratectomy (IE-PRK), to treat regression after laser in situ keratomileusis (LASIK).SettingIMO Instituto de Microcirugı̂a Ocular de Barcelona, Cornea and Refractive Surgery Unit, Autonoma University of Barcelona, Barcelona, Spain; Vall d’Hebron Hospital, Department of Ophthalmology, INSERM, University Hospital, Toulouse, France.MethodsThis open but uncontrolled prospective pilot study assessed the efficacy, predictability, and stability of IE-PRK in 21 eyes of 21 patients who had previous LASIK for myopia or myopic astigmatism with a mean spherical equivalent (SE) refraction of −9.80 diopters ± 2.95 (SD). After LASIK, the eyes regressed to a mean of −1.93 ± 0.82 D. They were retreated with IE-PRK, in which a photoablation was performed directly in the epithelium without damage to Bowman’s membrane. Follow-up was up to 1 year.ResultsEight of the 21 eyes (38%) were emmetropic at 6 months and 11 (52.4%) had a refraction between −0.50 and +0.50 D. Refraction was stable from the second week to the first year, with no significant differences among the mean SEs at 10 days, 6 weeks, and 6 and 12 months.ConclusionThe preliminary results of this small series indicate that IE-PRK appears to be safe, especially in selected cases; 1 line of lost best spectacle-corrected visual acuity occurred in 5% of eyes.     

Corneal keratocyte deficits after photorefractive keratectomy and laser in situ keratomileusis

PURPOSE: To measure changes in keratocyte density up to five years after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). DESIGN: Prospective, nonrandomized clinical trial. METHODS: Eighteen eyes of 12 patients received PRK to correct a mean refractive error of -3.73 +/- 1.30 diopters, and 17 eyes of 11 patients received LASIK to correct a mean refractive error of -6.56 +/- 2.44 diopters. Corneas were examined by using confocal microscopy before and six months, one year, two years, three years, and five years after the procedures. Keratocyte densities were determined in five stromal layers in PRK patients and in six stromal layers in LASIK patients. Differences between preoperative and postoperative cell densities were compared by using paired t tests with Bonferroni correction for five comparisons. RESULTS: After PRK, keratocyte density in the anterior stroma decreased by 40%, 42%, 45%, and 47% at six months, two years, three years, and five years, respectively (P < .001). At five years, keratocyte density decreased by 20% to 24% in the posterior stroma (P < .05). After LASIK, keratocyte density in the stromal flap decreased by 22% at six months (P < .02) and 37% at five years (P < .001). Keratocyte density in the anterior retroablation zone decreased by 18% (P < .001) at one year and 42% (P < .001) at five years. At five years, keratocyte density decreased by 19% to 22% (P < .05) in the posterior stroma. CONCLUSIONS: Keratocyte density decreases for at least five years in the anterior stroma after PRK and in the stromal flap and the retroablation zone after LASIK.     

A mathematical model for laser in situ keratomileusis and photorefractive keratectomy

PURPOSE: The purpose of ablation refractive surgery is to remove the refractive error from the inherently asymmetric aspheric cornea. Although the technique is gaining wide acceptance and popularity, some patients are left with irregular corneas. Our objective was to develop a methodology to analyze corneal shape, reduce the shape to arcs, modify the local arc value to the desired new arc value, and render a new continuous Euclidean surface without discontinuity. METHODS: The method to reconstruct the corneal surface consists of importing scanner output elevation data points into a computer-aided design (CAD) application to form the surface model. The corneal arc measurements are derived at 5 degrees increments and centered about the Gauss point of symmetry. Each arc is manipulated to adjust the corresponding arc on the proposed corneal surface to reflect the new arc value, correcting for the refractive error. The method determines the amount of corneal tilt and ablation depth at a given diameter required for the refractive error with a smooth transition zone to the base cornea. RESULTS: The case example is a patient who began with a spherical refraction of -8.75 D and after LASIK was emmetropic, but had irregular astigmatism and 20/30 best spectacle-corrected Snellen visual acuity. The proposed mathematical model compares the achieved surface shape to the mathematically planned surface contour. An enhancement procedure to remove the LASIK-induced corneal irregularity was designed. CONCLUSION: A mathematical technique to plan myopic ablative surgery to make the corneal surface regular and symmetric is proposed.     

Haze after laser in situ keratomileusis in eyes with previous photorefractive keratectomy.

In cases with previous photorefractive keratectomy (PRK), there is a risk of developing severe haze after laser in situ keratomileusis (LASIK). We report 3 patients (4 eyes) who developed severe haze after LASIK treatment for residual myopia following PRK. Both PRK and LASIK procedures were performed using the VISX 20/20 excimer laser. We report the grade of haze, amount of regression, and visual acuity after the patients were treated with topical steroids. In 2 eyes, the uncorrected visual acuity was 1.0 after 1 year with grade I haze. In the other 2 eyes, there was a residual refractive error, and the best spectacle-corrected visual acuity was 0.7 with grade II haze.     

Surgical outcomes of photorefractive keratectomy and laser in situ keratomileusis by inexperienced surgeons

PURPOSE: To investigate the results of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) procedures performed by novice ophthalmologists and compare the results with those of experienced refractive surgeons. SETTING: Doheny Eye Institute, University of Southern California, Los Angeles, and Department of Ophthalmology, University of California, Irvine, California, USA. METHODS: In this retrospective case series, data were examined from the first PRK procedures by 33 consecutive ophthalmologists and the first LASIK procedures by 19 consecutive ophthalmologists. Preoperative and postoperative uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), as well as intraoperative and early postoperative complications, were recorded. RESULTS: In the PRK group, 33.3% of eyes achieved a UCVA of 20/20 and 87.8%, 20/40 or better; 54.5% were within +/-0.5 diopter (D) of emmetropia and 87.8%, within +/-1.0 D. Two eyes with a preoperative spherical equivalent of greater than -11.0 D lost 2 lines of BSCVA. If eyes with low myopia (相似文献   

准分子激光屈光性角膜术治疗近视性屈光参差后的双眼影像不等和立体视

目的：评估轴性和屈光性两组近视性屈光参差（ＭＡ）经准分子激光屈光性角膜术（ＰＲＫ／ＬＡＳＩＫ） 矫正后的双眼影像不等检查结果（ＢＡ） 与理论计算值（ ％ Ｓｉｚｅ Ｄｉｆｆｅｒｅｎｃｅ,％ ＳＤ） 的关系,了解ＭＡ患者术后ＢＡ 和立体视的状况。方法：对４０ 例屈光度差≥２．５０Ｄ的近视患者行ＰＲＫ／ＬＡＳＩＫ,术后作ＢＡ和立体视检查,分别将两组的ＢＡ与％ＳＤ作比较;按术前屈光度差１．００Ｄ分四组,就术后ＢＡ和立体视进行比较;以不同矫正视力分两组,分析视力与立体视的关系。结果：ＢＡ与％ ＳＤ差异有显著性;不同屈光度差的ＭＡ患者,术后ＢＡ 及立体视差异无显著性,矫正视力与术后立体视关系密切。结论：轴性ＭＡ,屈光度差越大,％ ＳＤ较ＢＡ增大越明显,屈光性ＭＡ,％ ＳＤ明显小于ＢＡ。屈光度差在２．５０ ～８．００Ｄ范围时,ＭＡ患者ＰＲＫ／ＬＡＳＩＫ术后的ＢＡ和立体视状况无明显差异。矫正视力越好,术后立体视的恢复也越佳     

PRK与LASIK治疗高度近视的实验研究

研究ＰＲＫ与ＬＡＳＩＫ治疗兔眼高度近视的组织病理学损害。方法：对十只新西兰大白兔右眼行ＰＲＫ,左眼行ＬＡＳＩＫ,手术范围－１０．０Ｄ,分别于术后十天、一月、三月、半年随机选取动物摘除双眼,行光镜及电镜检查。结果：ＰＲＫ术后角膜上皮、上皮基底膜、前弹力层、浅层基质发生了损伤,故引起了不同程度的组织病理学损害,一至三月时最为明显,半年时减轻。ＬＡＳＩＫ术后,角膜细胞正常,胶原纤维规则排列,组织病理学损害较轻。结论：ＰＲＫ与ＬＡＳＩＫ矫正高度近视均不会造成长期的组织病理学损害,但从组织学比较而言,ＬＡＳＩＫ是一种更好的选择     

Diadenosine polyphosphates after laser in situ keratomileusis and photorefractive keratectomy refractive techniques

Purpose: To study the concentrations of diadenosine polyphosphates in the ocular surface after PRK and LASIK. Methods: Sixty‐one patients (30 males and 31 females) with ages ranging from 20 to 63 (34.04 ± 9.13 years) were recruited in Balear Institute of Ophthalmology, Palma de Mallorca, Spain. LASIK was performed in 92 eyes of 46 patients and PRK in 25 eyes of 15 patients. Variations in the levels of diadenosine polyphosphate (Ap₄A and Ap₅A), Schirmer I (Jones test), TBUT, corneal staining together with the Dry Eye Questionnaire to evaluate discomfort and dryness were studied. All tests were performed at the preoperative visit and at 1‐day, 2‐week, 1‐month and 3‐month postoperative visits. Results: Ap₄A showed a 5 and 3.5 fold increase at the 1‐day visit for LASIK and PRK, respectively. LASIK patients continued having higher statistically significant concentrations (p = 0.01) all over the follow‐up. Ap₅A showed no significant differences at any visit. Tear volume decreased during the 3 months in LASIK. The PRK cases had a normal volume at 1 month. TBUT in LASIK increased at the 1‐day visit (p = 0,002) and decreased from the 2 weeks onwards and for the PRK, decreased by a 35% at the 1‐day visit and kept reduced for a month. Discomfort only increased at the 1‐day visit (p = 0.007). Dryness frequency was similar in all visits. Conclusions: Ap₄A levels only are increased in refractive surgery patients during the first day after the surgery. This increasing suggests that Ap₄A may help accelerating the healing process.