准分子激光角膜切削术治疗圆锥角膜行角膜表层镜片术后的屈光不正

目的探讨角膜表层镜片术（EP）联合Ⅱ期准分子激光角膜切削术（PRK）治疗圆锥角膜完成期的临床疗效。方法（1）病例入选标准：①EP入选标准：圆锥角膜完成期患者,角膜中央区无瘢痕,最佳矫正视力（BCVA）≤0．3,角膜曲率≤60．0D;②Ⅱ期行PRK入选标准：角膜拆线后3个月内散光变化〈0．5D,年龄〉18岁,无其他眼部疾病。（2）手术治疗：对进入手术入选标准的患者常规Ⅰ期行EP,Ⅱ期行PRK。（3）术后随访：观察术后植片情况,记录视力、散光变化及并发症发生情况。结果8例（10只眼）患者接受了Ⅰ期EP联合Ⅱ期PRK,术后平均随访时间为40．6（30～94）个月。（1）视力：EP术后12～18个月（角膜全拆线行PRK术前）,10只眼BCVA均〉0．3,其中0．3～0．5者1只眼,≥0．5者9只眼;行PRK术后〉12个月,10只眼BCVA均≥0．5,其中5只眼BCVA达到1．0。（2）角膜散光：EP术前平均角膜散光为（7．3±1．8）D,EP术后12～18个月平均角膜散光为（3．8±1．6）D,PRK术后24个月以上,平均角膜散光为（1．6±0．9）D。（3）植片情况：EP术后所有植片透明,无免疫排斥反应发生。PRK术后1只眼发生0．5级的角膜上皮下雾状混浊,未见圆锥角膜复发。（4）术后并发症与处理：1例（1只眼）患者EP术后当天继发青光眼,前房消失,急诊行前房重建后缓解;1例（1只眼）患者EP术后植床出现较大皱褶,1例（1只眼）患者EP术后3个月内缝线松动,行植片重缝后缓解。结论Ⅰ期EP联合Ⅱ期PRK可能是治疗圆锥角膜完成期的有效方法,行PRK术后视力长期稳定。     

Long-term outcomes of photorefractive keratectomy and laser-assisted subepithelial keratectomy in children

PURPOSE: To assess the long-term refractive, visual acuity, binocular vision, and quality-of-life outcomes of photorefractive keratectomy (PRK) and laser-assisted subepithelial keratectomy (LASEK) in children. SETTING: Non-hospital surgical facility with follow-up in a hospital clinical setting. METHODS: In this retrospective review, 56 eyes of 39 patients had PRK or LASEK under general anesthesia. Patients were examined preoperatively and postoperatively at 2 and 6 months and 1 year and then annually for a minimum of 3.5 years. Recorded variables included demographics, refractive error, best corrected visual acuity (BCVA), stereopsis, corneal haze, and quality of life. RESULTS: The mean age at surgery was 6.5 years (range 1.0 to 17.4 years). At the final postoperative examination (mean 5.15 years), the mean spherical equivalent was -1.73 diopters (D) in all patients, -3.20 D in PRK patients, and -1.37 D in LASEK patients. Refraction and corneal clarity were stable over the long term in all eyes. In 28 eyes that were measurable preoperatively, visual acuity improved by a mean of 1.6 lines (range 0 to 7 lines). Seven patients (18%) had measurable stereopsis before surgery and 19 (49%), after PRK or LASEK. No patient had reduced BCVA or loss of binocular fusion postoperatively. On a quality-of-life questionnaire, no family recorded negative opinions of the procedure or negative social or functional outcomes postoperatively. CONCLUSION: Photorefractive keratectomy and LASEK were effective and stable surgical alternative treatments in children with refractive errors who were unable to tolerate or who failed conventional methods of treatment.     

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.     

Topography versus non-topography-guided photorefractive keratectomy with corneal cross-linking variations in keratoconus

AIM: To compare the visual results of non-topography-guided and topography-guided photorefractive keratectomy (PRK) applying sequential and simultaneous corneal cross-linking (CXL) treatment for keratoconus. METHODS: Interventional and comparative prospective study. Sixty-nine eyes (36 patients) suffering from keratoconus (stages 1 Amsler-Krumeich classification) were divided into four groups: sequential topography-guided photorefractive keratectomy with CXL, simultaneous topography-guided photorefractive keratectomy with CXL, simultaneous non-topography guided photorefractive keratectomy with CXL, and sequential non-topography guided photorefractive keratectomy with CXL. The main outcome measures were pre- and postoperative uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (CDVA), manifest refraction, contrast sensitivity, and keratometry. RESULTS: All analyzed visual, contrast sensitivity, and refractive parameters showed a significant improvement in the four groups (all P<0.05). A noticeable improvement was seen in keratometry in all the groups, and a remarkable difference was observed between topography-guided groups in comparison to non-topography-guided groups (P<0.05). Interestingly, the improvement in all parameters showed a degree of stability to the end of the follow-up. CONCLUSION: The treatment priorities in all four groups are safety, efficacy, and predictability in the correction of the sphero-cylindrical errors in mild and moderate keratoconus. No significant differences among groups in the recorded objective outcomes were found.     

Excimer laser photorefractive keratectomy in myopic eyes with corectopia.

Corectopia, the eccentric displacement of the pupil, may be associated with other abnormalities such as axial high myopia or ectopia lentis. We report the case of a patient presenting for surgery to correct bilateral myopia of 6.50 diopters (D) associated with corectopia. Excimer laser ablation was decentered and performed on the center of the abnormal pupils. After a 2 year follow-up, best corrected visual acuity was 20/20 with -1.00 D correction in each eye. To our knowledge, this is the first report of excimer laser photorefractive keratectomy for myopia associated with corectopia. The satisfactory results suggest that in abnormally eccentric pupils, excimer laser treatment of myopia may be successful when it is centered on the deviated pupil.     

Choroidal neovascularization in myopic eyes after photorefractive keratectomy

PURPOSE: To evaluate the incidence, characteristics, and results of treatment of choroidal neovascularization (CNV) in myopic eyes corrected by photorefractive keratectomy (PRK). SETTING: University Miguel Hernández, Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS: This study was of the incidence of CNV in 5936 consecutive eyes that had PRK for the correction of myopia. Mean follow-up was 38.5 months +/- 17.4 (SD). RESULTS: Extrafoveal CNV developed in the right eye of a 44-year-old woman 26 months after PRK for the correction of -12.00 diopters (D) of myopia. The follow-up after PRK was 38 months. Best corrected visual acuity (BCVA) before PRK was 20/40 (spherical equivalent [SE] -12.00 D). After PRK, BCVA was 20/32 SE -1.75 D). The CNV was treated by direct argon-green laser photocoagulation and did not recur in the subsequent 12 months). After CNV treatment, BCVA was 20/32 (SE -2.25 D). CONCLUSION: The incidence of CNV after PRK for myopia was low. Choroidal neovascularization is a possible complication in myopic eyes, and the risk exists before PRK. After PRK, the risk of CNV in myopic patients did not increase.     

Retinal detachment in myopic eyes after photorefractive keratectomy

PURPOSE: To analyze the incidence and characteristics of retinal detachment (RD) in myopic patients who had photorefractive keratectomy (PRK). SETTING: Universidad Miguel Hernández, Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS: The incidence of RD in 5936 consecutive eyes that had PRK to correct myopia was studied. Mean follow-up was 38.5 months +/- 17.4 (SD). RESULTS: Retinal detachment occurred in 5 eyes (0.08%); 2 in women and 3 in men. The mean interval between PRK and RD was 21. 00 +/- 15.89 months (range 9 to 48 months). The mean best corrected visual acuity (BCVA) after PRK and before RD development was 20/81 (range 20/200 to 20/25). After RD repair, the mean BCVA was 20/460 (range 20/2000 to 20/29). In 4 of the 5 eyes, BCVA after RD was within 1 line of the preoperative value; in 1 eye, it decreased from 20/40 to 20/2000. The mean spherical equivalent (SE) before RD treatment was -1.35 +/- 1.08 diopters (D) (range 0 to -3.00 D) and after RD treatment, -2.95 +/- 0.83 D (range -2.00 to -4.00 D). Differences between SE before and after RD treatment were statistically significant (P =.01, paired Student t test). CONCLUSIONS: The incidence of RD after PRK to correct myopia was 0.08%. In 4 of 5 eyes, there was little or no visual loss; but in the group as a whole, there was a significant increase in myopic SE.     

Results of photorefractive keratectomy in keratoconus suspects at 4 years

PURPOSE: We studied the long-term results of photorefractive keratectomy (PRK) in keratoconus suspects detected by videokeratography (TMS). METHODS: Bilateral inferior corneal steepening was detected in 6 candidates for PRK presenting with moderate myopia or astigmatism. Mean follow-up was 44.5 +/- 4.4 months (range, 38 to 54 mo). Mean spherical equivalent refraction was -5.18 +/- 1.60 D (mean sphere, -4.73 D; mean cyclinder, -0.92 D) which was stable for at least the preceding year. The quantitative measurement of inferior corneal steepening (I-S value) was greater than +1.60 (mean, 1.83 +/- 0.11) in all eyes. An Aesculap Meditec Mel 60 excimer laser was used for the PRK procedures and mean follow-up was 44.5 months. Postoperative pachymetric measurements were also performed in 6 eyes. RESULTS: Postoperative uncorrected visual acuity was 20/20 in 8 eyes (66.6%) and 20/32 or better in all eyes with a mean postoperative spherical equivalent refraction of -0.70 +/- 0.74 D (mean sphere, -0.63 D; mean cyclinder, -0.39 D). Five eyes (41.6%) were within +/- 0.50 D spherical equivalent refraction. Inferior steepening was associated with thinning of the inferior cornea which was statistically significantly thinner than the superior thickness (Student's t-test, P < .05). There were no wound healing problems or any sign that the excimer laser adversely affected the cornea during follow-up. CONCLUSIONS: Photorefractive keratectomy seems to be a safe procedure for reducing or eliminating myopia or astigmatism in keratoconus suspect eyes-most probably forme fruste keratoconus-with a stable refraction, but this may be different in eyes with early keratoconus, known to be a progressive disease.     

非角膜地形图引导PRK联合角膜胶原交联术治疗圆锥角膜

目的：评估非角膜地形图引导圆锥角膜患者行光折变角膜切除术(PRK)和角膜胶原交联术(CXL)的视力、屈光度和临床疗效。

方法：术后1mo, 3mo, 6mo and 12mo对34例患者未矫正视力(UDVA)和矫正距离视力(CDVA),平、陡角膜测量读数以及并发症进行评估。

结果：共34例患者平均年龄为23.3±4.0岁。UDVA和CDVA显著提高,且术后1a恢复平稳。通过超过1a的定期随访,T检验显示术前术后值有显著不同(P<0.05)包括视力,球面和柱面变化。Fourier术后图像分析显示轴向位移垂直于术前轴。

结论：非角膜地形图引导PRK联合CXL对于治疗圆锥角膜是一种安全有效的手术选择,能够提高UDVA,CDVA和屈光状态。术后3mo达到稳定状态,与非角膜地形图引导PRK相比,地形图引导的唯一优势可能是通过Fourier术后分析,在某些患者中,球镜和柱镜轴位漂移。     

Long-term functional and topographic results seven years after epikeratophakia for keratoconus

PURPOSE: To analyze the long-term effect of epikeratophakia (EKP) on corneal topography and visual acuity of eyes with keratoconus. METHODS: Retrospective study of 36 eyes 7.2 years after EKP. Four eyes underwent penetrating keratoplasty (PKP) and were excluded from further evaluation. Best-corrected visual acuity (BCVA) values were obtained from 32 eyes, corneal refraction and astigmatism from 23 eyes, surface asymmetry index (SAI) and surface regularity index (SRI) from 17 consecutive eyes that were operated upon after 1991, when the Tomey Topographic Modeling System became available. RESULTS: Only four eyes needed PKP. In addition to EKP six eyes had compression sutures and/or relaxing incisions, and one eye underwent photorefractive keratectomy. Mean refractive power of the cornea decreased from 51.8 to 45.8 and astigmatism from 7.2 to 3.8. SAI improved from 3.2 to 0.9 and SRI from 3.7 to 0.9. Mean BCVA was 0.3 preoperatively and 0.6 upon last follow-up. CONCLUSIONS: EKP was able to render PKP unnecessary in 32 of 36 eyes during the entire observation period. It was successful in permanently flattening the ectatic cornea and reducing astigmatism while restoring a symmetrical and smooth corneal surface. As a result, visual acuity improved considerably. In view of the young age of keratoconus patients needing surgery, and the fact that the lifetime of full-thickness corneal grafts is limited, EKP should be considered a valuable alternative to PKP in contact-lens-intolerant cases of keratoconus without central scarring.     

Combination of photorefractive and phototherapeutic keratectomy in the treatment of keratoconus

Twenty patients (28 eyes) with primary keratoconus of stages I-II (Amsler) were operated using photorefraction keratectomy (PRK) supplemented by phototherapeutic keratectomy (PRK). Mean UCVA before surgery was 0.04 +/- 0.004, BCVA 0.68 +/- 0.03. Eximer laser EC-5000(NIDEK) was used in the treatment. PRK included spherical, cylindrical ablations, or both. The diameter of ablation zone in PRK was 6 mm. in PTK the diameter of ablation zone was 8 mm, transition zone 9 mm. In PTK the ablation zone was decentered towards the cone apex (according to corneal computer topography). The method is patented in the Russian Federation. Visual acuity without correction notably improved in all 20 patients and its mean value after the operation was 0.73 +/- 0.03, 68% eye having visual acuity of 1.0. In one female patient keratoconus progressed 6 months after the operation. Haze was observed in 1 patient as a result of delayed reepithelialization. No progress of keratoconus was observed in other patients (period of observation 17.3 +/- 1.5 months). Hence, the new PRK-PTK method is an effective method for treating primary keratoconus of the first-second stage according to Amsler; the method arrests the progress of the condition in 96% cases.     

Corneal haze among blue eyes and brown eyes after photorefractive keratectomy

BACKGROUND: To compare the incidence and severity of corneal haze after photorefractive keratectomy (PRK) among white patients with blue eyes and Saudi patients with brown eyes. DESIGN: Retrospective, nonrandomized, comparative trial. PARTICIPANTS: A total of 150 patients (71 females and 79 males) were included in this study. Two hundred sixty-six eyes of 150 patients were subjected to PRK. One hundred blue eyes of 50 white patients and 166 brown eyes of 100 Saudi patients were included in this study. METHODS: Two hundred sixty-six eyes of 150 patients were subjected to PRK with the Chiron Technolas Keracor 117C for the correction of myopia and astigmatism. MAIN OUTCOME MEASURES: All patients had complete ophthalmologic examinations, visual acuity testing, intraocular pressure, pachymetry, corneal haze assessment (0-4+), and computerized corneal topography. RESULTS: There were 266 eyes of 150 patients with 100 blue irides and 166 brown irides. The spherical equivalent was -0.50 diopter (D) to -8.75 D. The mean postoperative spherical equivalent at 6 months was -0.063 D (standard deviation [SD], +/-0.595) in blue eyes compared to -0.28 D (SD, +/-0.683) in brown eyes (P = 0.006). Ninety-five (95%) of 100 of the blue eyes achieved +/- 1 D of attempted correction compared to 148 (89.2%) of the 166 brown eyes. All patients with blue eyes had a visual acuity of 20/30 or better compared to 153 (92.2%) of the 166 brown eyes (P = 0.009). Forty-eight (18.04%) eyes had minimal to mild haze, 3 (1.12%) eyes had moderate haze, and 2 (0.75%) eyes had severe haze. The incidence of corneal haze among brown eyes was 48 (28.9%) of 166 eyes compared to 5 (5%) of 100 in blue eyes (P < 0.001). The difference remained significant after adjustment for age and gender with a P value of 0.0283. The relative risk for developing haze in brown eyes was found to be 7.72. CONCLUSION: The incidence of corneal haze after PRK was significantly higher among Saudi patients with brown irides than among white patients with blue irides. This suggests that racial factors may play a role in the development of corneal haze.     

One-year follow-up of epikeratophakia for keratoconus

We report 1-year follow-up findings on 42 of the first epikeratophakia procedures performed for keratoconus at the Helsinki University Central Hospital. Altogether 40 patients (42 eyes) received epikeratophakia grafts to flatten their cones. The age of the patients ranged between 19 and 44 years. The mean follow-up for these patients was 10.7 ± 4.4 months, and in 12 patients follow-up extended to over 12 months. Overall, the success rate for the procedure was 93%, and with repeated surgery it was 97% for all patients; in all patients uncorrected visual acuity improved. Preoperatively 82% of the patients had uncorrected acuity worse than 20/400, while all patients followed for 1 year had uncorrected visual acuity better than 20/400. At 6 and 12 months postoperatively best corrected visual acuities were all returned to within one line of their preoperative best corrected acuity; in 83% acuities were 20/40 or better 12 months postoperatively. Four patients out of 12 followed for 1 year needed no postoperative overrefraction at all. The mean flattening by keratometry readings was 9.8 diopters (D) and the mean decrease in myopia in terms of spherical equivalent was 5.3 D. The degree of irregular astigmatism was measured in five cases using LSU topographical corneal shape analysis, and showed that the mean preoperative irregular astigmatism of 3.9 D was reduced to 1.3 D in the long-term analysis. One case report is presented to show in detail the topographical changes induced by epikeratophakia in keratoconus. The noninvasive nature of the epikeratophakia procedure makes it a safe and desirable option for the treatment of keratoconus.This research was supported in part by grants from the Juselius Foundation and by the Finnish Eye and Tissue Bank Foundation, Finland