Corneal lamellar flap retraction after LASIK following penetrating keratoplasty

PURPOSE: To describe a case of lamellar flap retraction after laser in situ keratomileusis (LASIK) to correct myopia and astigmatism after penetrating keratoplasty (PKP). METHODS: Eleven months after PKP, a 34-year-old man underwent uneventful LASIK. Preoperative manifest refraction was -5.50 + 4.00 x 55, giving a best-corrected visual acuity (BCVA) of 20/20. Three days after LASIK, the central cornea was clear with a 1- to 2-mm displacement and marked swelling of the inferior edge of the lamellar corneal flap, without central striae. The patient's uncorrected visual acuity (UCVA) was 20/60. The flap was repositioned, sutured with 6 10-0 nylon interrupted sutures, and covered with a bandage contact lens. RESULTS: Five months after the repair, the cornea was clear, UCVA was 20/400, and manifest refraction was -9.50 + 6.00 x 75, giving a BCVA of 20/60. Three years later, manifest refraction was - 9.00 + 4.00 x 70, giving a BCVA of 20/40+2. CONCLUSION: In LASIK surgery after PKP, there is a risk of flap edema leading to retraction of the transplant wound. It may therefore be advisable to wait at least 1-2 years after PKP before performing LASIK. Patients who have corneal transplants should also be warned that they might have unique risks in LASIK treatment that may result in the loss of vision.     

Photorefractive keratectomy with mitomycin C for the management of a LASIK flap complication following a penetrating keratoplasty

OBJECTIVE: To evaluate the safety and efficacy of photorefractive keratectomy (PRK) with mitomycin C (MMC) following a buttonhole secondary to attempted laser in situ keratomileusis (LASIK) in an eye that had undergone a prior penetrating keratoplasty (PKP). METHODS: Case report and review of the literature. A 26-year-old man underwent PRK with MMC following a buttonhole flap complication after LASIK in an eye that had undergone a PKP for keratoconus. RESULTS: Three months following the procedure, the patient demonstrated a clear cornea and a best-corrected visual acuity of 20/20. CONCLUSION: To our knowledge, this is the first case report of buttonhole during LASIK following a PKP and the use of PRK to treat a LASIK flap complication following a successful PKP. In addition, this is the first case report of prophylactic use of MMC to prevent corneal haze with PRK following PKP. A buttonhole is a rare complication following LASIK for residual refractive error following PKP, which can be successfully managed with PRK and prophylactic MMC.     

Flap-induced refraction change in LASIK after penetrating keratoplasty

PURPOSE: To further analyze the refractive and topographic changes occurring with microkeratome lamellar keratotomy and to investigate possible factors associated in eyes with previous penetrating keratoplasty (PK). METHODS: The Hansatome microkeratome was used to create a lamellar corneal flap in 21 eyes of 19 patients after PK. The laser ablation was not performed in the first stage. Pre- and postoperative refractions and corneal topographies were compared to evaluate possible changes induced by the keratotomy. RESULTS: Twenty-one eyes were analyzed in this study. Mean time between PK and lamellar keratotomy was 36.63 +/- 28.23 months (range: 12 to 120 months). No microkeratome-related flap complications occurred. Previous to the keratotomy, the mean spherical equivalent refraction was -4.26 +/- 3.41 diopters (D), mean refractive astigmatism was -4.71 +/- 2.27 D, and mean topographic astigmatism was 5.28 +/- 2.94 D. After keratotomy, eyes showed statistically significant changes in spherical equivalent refraction from preoperative values (P = .025), with 3 eyes showing changes > 2.00 D. Average refractive and topographic astigmatism did not change significantly from before to after keratotomy. However, surgically induced astigmatism (SIA) calculated through vector analysis was > 1.01 in 11 (52.4%) eyes. A statistically significant correlation was found between the SIA values and preoperative refractive astigmatism (P = .025). CONCLUSIONS: Lamellar keratotomy as part of two-stage LASIK in eyes with prior PK led to refractive changes that justify the use of this technique, especially in eyes with high degrees of preoperative astigmatism.     

Post-LASIK corneal flap displacement following penetrating keratoplasty for bullous keratopathy

OBJECTIVE: To report 3 patients who experienced late flap dislocation after laser in situ keratomileusis (LASIK) in eyes that had undergone prior penetrating keratoplasty (PKP) for bullous keratopathy. METHODS: Retrospective chart review of 2 referral corneal and refractive surgery practices, case reports, and literature review. RESULTS: Three patients (mean age 58.3 years, 2 male, 1 female), all status post-corneal transplant for bullous keratopathy, had residual myopic astigmatism and underwent LASIK for correction of their significant anisometropia. Flap dislocation occurred at a mean of 7 days (range 3 to 14 days) following the LASIK procedure. All patients had peripheral corneal edema in their recipient bed. All 3 patients required an additional surgical procedure for visual rehabilitation. CONCLUSION: Flap displacement may occur following LASIK in patients who have undergone PKP for bullous keratopathy. The endothelial pump function, which is vital to maintaining flap adherence, may be compromised in these patients. We suggest that patients with a history of PKP and endothelial compromise who undergo LASIK wear protective shields for a longer than normal period and be followed closely to reduce the risk of flap slippage.     

Endophthalmitis following penetrating keratoplasty

To determine the incidence of infectious endophthalmitis in the early postoperative period following penetrating keratoplasty, and the type and origin of the causative organisms, all cases of penetrating keratoplasty performed at the Emory University affiliated hospitals between January 1977 and March 1982 were reviewed. Four (0.2%) of the 1,876 cases developed infectious endophthalmitis. In all four, evidence of infection developed within 72 hours, and in three the donor rim culture grew the same organism as was obtained from the anterior chamber or vitreous. The causative organisms were Streptococcus pneumoniae, Staphylococcus aureus, group D Streptococcus-enterococcus, and Pseudomonas aeruginosa. Eyes with positive donor rim cultures had a 22-fold increased incidence of endophthalmitis.     

LASIK for post penetrating keratoplasty astigmatism and myopia

AIMS: To report the results of a series of patients who were treated with LASIK to correct post penetrating keratoplasty ametropia. METHODS: 26 eyes of 24 patients underwent LASIK to correct astigmatism and myopia after corneal transplantation; 14 eyes also received arcuate cuts in the stromal bed at the time of surgery. The mean preoperative spherical equivalent was -5.20D and the mean preoperative astigmatism was 8.67D. RESULTS: The results of 25 eyes are reported. The mean 1 month values for spherical equivalent and astigmatism were -0.24D and 2.48D respectively. 18 eyes have been followed up for 6 months or more. The final follow up results for these eyes are -1.91D and 2.92D for spherical equivalent and astigmatism. The patients undergoing arcuate cuts were less myopic but had greater astigmatism than those not. The patients receiving arcuate cuts had a greater target induced astigmatism, surgically induced astigmatism, and astigmatism correction index than those eyes that did not. One eye suffered a surgical complication. No eyes lost more than one line of BSCVA and all eyes gained between 0 and 6 lines UCVA. CONCLUSIONS: LASIK after penetrating keratoplasty is a relatively safe and effective procedure. It reduces both the spherical error and the cylindrical component of the ametropia. Correction of high astigmatism may be augmented by performing arcuate cuts in the stromal bed.     

Topography-guided LASIK with the wavelight laser after penetrating keratoplasty

PURPOSE: To report a case of topography-guided LASIK in a patient after previous penetrating keratoplasty. METHODS: A 20-year-old man who had previous penetrating keratoplasty in his right eye for keratoconus and was intolerant to spectacles and contact lenses underwent topography-guided LASIK. RESULTS: Three months postoperatively, the patient's uncorrected visual acuity in the right eye was 20/25(+2). Best spectacle-corrected visual acuity was 20/20, with a manifest refraction of +0.25 -0.75 x 40 degree. Conclusion: Topography-guided LASIK is a useful therapeutic modality to address corneal irregularity after penetrating keratoplasty.     

Cataract extraction following penetrating keratoplasty

OBJECTIVE: To assess the safety of cataract extraction following penetrating keratoplasty for corneal graft survival and to evaluate visual and refractive outcomes in corneal graft patients undergoing cataract extraction. METHODS: Retrospective chart review of 29 eyes of 24 patients with corneal grafts who underwent cataract extraction from January 1, 1993 to December 31, 2002, followed on the Cornea Service at Wills Eye Hospital. RESULTS: The mean time from penetrating keratoplasty to cataract extraction was 8.4 years (range 2 months to 36 years). Following cataract extraction, the corneal grafts remained clear in all but 1 eye (3%), during an average follow-up time of 44.5 months (range 3-118 months). All of the remaining patients benefited from improved visual acuity, with 15 of 28 patients having a postoperative best-corrected visual acuity of 20/30 or better. Patients also benefited from decreased absolute spherical refractive error, with a preoperative mean value of 6.6 +/- 3.4 D compared with 2.4 +/- 1.6 D postoperatively, while cylindrical refractive error remained relatively stable at 3.2 +/- 2.9 D preoperatively and 2.8 +/- 2.4 postoperatively. The patient who developed graft failure had 3 episodes of preoperative endothelial rejection and a clear corneal graft at the time of cataract surgery. CONCLUSIONS: Cataract surgery following penetrating keratoplasty is a safe and effective procedure, with a low but definite risk of corneal graft failure. In patients with clear grafts and visually significant cataracts, cataract extraction alone is preferred over repeat penetrating keratoplasty and cataract extraction.     

Efficacy of nonsimultaneous bilateral LASIK after nonsimultaneous bilateral penetrating keratoplasty

PURPOSE: To show if nonsimultaneous bilateral laser in situ keratomileusis (LASIK) is a safe and effective procedure for patients with bilateral penetrating keratoplasty (PKP). METHODS: Five patients (10 eyes), with keratoconus, underwent PKP separately in each eye. After an average PKP follow-up of 45.8 months per eye, (range, 19-92 months), each eye underwent 1-stage LASIK using the Visx Star S3 laser to correct its residual refractive error. We used the cycloplegic refraction as the target for the LASIK surgery. Each patient had his or her eyes done separately 3 weeks apart. RESULTS: Pre-LASIK myopia averaged -3.93 +/- 2.9 D, ranging from -10.00 to +0.75 D. Pre-LASIK astigmatism averaged -3.25 +/- 0.80 D, ranging from -1.75 to -4.50 D. Mean pre-LASIK keratometry was 45.4 +/- 2.6, ranging from 42.2 to 50.5. Uncorrected visual acuity pre-LASIK averaged 20/220, ranging from 20/60 to 20/400. Best-corrected spectacle visual acuity (BCSVA) pre-LASIK averaged 20/22, ranging from 20/20 to 20/30. Nine eyes had no complications. One eye had a flap buttonhole during LASIK, and surgery was aborted. No vision was lost in this eye. Mean follow-up after LASIK in the 9 eyes was 17 +/- 15.2 months, (range, 4-56 months). Mean post-LASIK ametropia in these 9 eyes was +0.25 +/- 0.45 D, ranging from -0.50 to +0.75 D. Average post-LASIK astigmatism was -0.33 +/- 0.38 D, ranging from 0 to -0.75 D. In the 9 treated eyes, uncorrected vision post-LASIK averaged 20/25, ranging from 20/20 to 20/30. BCSVA post-LASIK averaged 20/21, ranging from 20/20 to 20/25. No lines of visual acuity were lost in any of the eyes. CONCLUSION: Young patients who have had bilateral PKP, with good postoperative vision and low levels of myopia, astigmatism, and minimal wound override, are good candidates for bilateral nonsimultaneous LASIK. Further studies can now be done on the performance of bilateral simultaneous LASIK in patients who have had corneal transplant surgery in both of their eyes.     

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.     

穿透角膜移植术后屈光不正的矫治

穿透角膜移植术(PKP)可使角膜病患者重见光明,是目前治疗角膜病盲最有效的手段,近年来由于免疫学和方法学的进步,术后角膜植片的透明率已有很大的提高.但手术部位多在光学中心,加之手术人员、设备等诸多因素的影响,几乎所有患者术后均存在不同程度的屈光不正而影响视力恢复,并引起不同程度的视疲劳,一直是眼科界难以解决的问题.分析屈光不正的成因,对术后屈光状态进行有效控制是值得深入研究的课题.对影响PKP术后屈光状态的因素及其主要矫治方法如配戴框架眼镜或角膜接触镜、选择性角膜拆线、松弛性切口、散光性角膜切削术、角膜楔形切除术、放射状角膜切开术、准分子激光手术等进行简要综述.