[A prospective randomized controlled study of antibiotic bone cement in the treatment of diabetic foot ulcer].

Objective: To investigate the clinical effects and related mechanism of antibiotic bone cement in treating diabetic foot ulcer (DFU). Methods: A prospective randomized controlled study was conducted. From August 2020 to August 2022, 24 patients with DFU who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University. According to the block randomization, the patients were divided into 2 groups, with 12 patients in each group. In antibiotic bone cement group, there were 7 male and 5 female patients, aged (64±8) years, with the ulcer area of (41±21) cm2. In silver sulfadiazine group, there were 8 male and 4 female patients, aged (62±8) years, with the ulcer area of (38±19) cm2. Under the condition of ensuring the patency of at least one main inferior genicular artery in each patient, the continuous vacuum sealing drainage was performed for 3-5 days after thorough debridement. Thereafter, the wounds in antibiotic bone cement group were treated with gentamicin-laden bone cement, and the wounds in silver sulfadiazine group were treated with silver sulfadiazine cream for dressing change. After 3 weeks of dressing change, the wound was covered with split-thickness skin graft from the lateral thigh on the affected side. Before debridement and after 3 weeks of dressing change, the blood flow intensities of wound tissue and normal skin tissue in foot were measured using laser Doppler flowmeter, and then, the percentage of relative blood flow intensity of wound and the change rate of blood flow intensity were calculated. After 3 weeks of dressing change, the wound margin tissue was taken, the number of CD31-positive neovascular and the vascular morphology were observed and detected by immunohistochemical staining, the morphology of blood vessels surrounded by CD31 and α-smooth muscle actin (α-SMA) double-positive cells was observed by immunofluorescence staining, the cell proliferation activity was evaluated by immunofluorescence staining (denoted as the ratio of Ki67 positive cells), and the protein expression of vascular endothelial growth factor receptor 2 (VEGFR2) was detected by Western blotting. The skin graft survival was observed 3-5 days after skin grafting, and the wound healing time was recorded. Data were statistically analyzed with independent sample t test and Fisher's exact probability test. Results: The percentages of relative blood flow intensity of wounds of patients before debridement were similar between the two groups (P>0.05). After 3 weeks of dressing change, the percentage of relative blood flow intensity of wounds and the change rate of blood flow intensity of patients in antibiotic bone cement group were (44.7±2.0)% and (129±12)%, respectively, which were significantly higher than (28.3±1.2)% and (41±8)% in silver sulfadiazine group (with t values of 24.15 and 20.97, respectively, P<0.05). After 3 weeks of dressing change, compared with those in silver sulfadiazine group, the number of CD31-positive neovascular in the wound margin tissue of patients in antibiotic bone cement group was significantly increased (t=33.81, P<0.05) with larger diameter and more regular arrangement, the vascular wall continuity surrounded by CD31 and α-SMA double-positive cells was better, and the ratio of Ki67 positive cells and protein expression of VEGFR2 were significantly increased (with t values of 40.97 and 47.38, respectively, P<0.05). On post skin grafting day 3-5, all the patients in antibiotic bone cement group and 8 patients in silver sulfadiazine group had good skin graft survival, while 4 patients in silver sulfadiazine group showed spotted/patchy skin graft necrosis, which were cured after corresponding treatment. The wound healing time of patients in antibiotic bone cement group was (47.1±2.9) d, which was significantly shorter than (58.8±2.3) d in silver sulfadiazine group (t=10.86, P<0.05). Conclusions: Compared with silver sulfadiazine, clinical application of antibiotic bone cement for treating DFU has the characteristics of accelerating wound healing and better reconstruction of local blood flow, which may be closely related to the fact that antibiotic bone cement promoted the local angiogenesis effectively in the wound through enhancing the expression of VEGFR2.

[Investigation and research on ticks carrying spotted fever group rickettsia in the border area of Tumen River Basin].

Objective: To understand the situation and genotype distribution of spotted fever group rickettsia (SFGR) in the border area of Tumen River Basin in free ticks in Yanbian Korean Autonomous Prefecture (Yanbian Prefecture), Jilin Province. Methods: From April to September, 2017, ticks were collected using flagging method from Hunchun, Tumen, Helong and Longjing cities in the Tumen River basin of Yanbian Prefecture. Outer membrane protein A (ompA) was detected by Polymerase Chain Reaction (PCR), then, the species were identified by gene sequencing and analyzed systematically. The positive rate of pools and MIR(minimum infection rate per 100 ticks,MIR) of SFGR were calculated, and the difference of positive rate of pools among ticks with different characteristics was compared by Chi-square test. Results: A total of 3 079 ticks were collected and divided into 536 pools. The positive rate of pools of SFGR nucleic acid was 39.7% (213 pools). The MIR of SFGR was 6.9%.The positive rate of pools of SFGR in Dermacentor silvarum, Haemaphysalis concinna, Haemaphysalis japonica, Haemaphysalis longicornis and Ixodes persulcatus were 80.4% (41/51), 14.0% (25/179), 20.2% (18/89), 78.9% (101/128) and 25.9% (21/81), and the difference was statistically significant (P<0.001). There was statistical difference in the positive rate of pools of SFGR in developmental stages of ticks (P<0.001); the positive rate of pools of female adults, male adults, nymph and larvae were 36.4% (95/261), 34.2% (67/196), 56.3% (40/71) and 7/8, and the MIR was 7.9%, 7.7%, 4.9% and 3.5%. The five genotype was detected which was Candidatus Rickettsia longicornii, Rickettsia raoultii, Rickettsia heilongjiangensis, Candidatus Rickettsia tarasevichiae,Rickettsia monacensis and have 98%-100% homology with known gene sequences. Candidatus Rickettsia longicornii, Rickettsia raoultii, Rickettsia heilongjiangensis and Candidatus Rickettsia tarasevichiae showed close evolutionary relationship with known specie (have 98%-100% homology with known gene sequences); Rickettsia monacensis showed Far from evolutionary relationship with known species (have 98% homology with known gene sequences). Conclusion: SFGR infection of ticks is common in the border areas of the Tumen River Basin. There was high diversity in SFGR species and tick species in the areas surveyed.

Vascular endothelial growth factor gene polymorphisms and colorectal cancer risk: a meta-analysis.

Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen involved in a number of pathologic processes, including angiogenesis, tumor growth and metastasis. Polymorphisms of the VEGF gene have been associated with susceptibility to colorectal cancer (CRC). However, the specific association still remains controversial. We made a meta-analysis of the association between VEGF gene polymorphisms and CRC risk. Only eight case-control studies were retrieved, with a total of 2337 CRC patients and 2032 healthy controls. Six VEGF gene polymorphisms were addressed in all studies included, +936C>T (rs3025039), -2578C>A (rs699947), -1154G>A (rs1570360), -634G>C (rs2010963), -460C>T (rs833061), and +405C>G (rs2010963). There was a significant association between -2578C>A polymorphism and susceptibility to CRC in the comparison of C allele carriers (CC + CA) versus AA (odds ratio = 0.77, 95% confidence interval = 0.62-0.96, P = 0.02). No association was found between +936C>T, -1154G>A, -634G>C, -460C>T, and +405C>G with susceptibility to CRC. We conclude that the C allele carrier (CC + CA) of VEGF -2578C>A polymorphism appears to be a protective factor for CRC.

Laser in situ keratomileusis with the VISX Star laser for myopia over -10.0 diopters.

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) for myopia over -10.00 diopters (D). SETTING: The Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: The prospective study included 332 eyes of 183 patients having LASIK with the VISX Star laser to correct myopia of -10.00 to -18.00 D. The eyes were divided into 3 groups according to the preoperative refraction: Group A (n = 208), -10.00 to -11.90 D; Group B (n = 94), -12.00 to -14.00 D; Group C (n = 30), -14.10 to -18.00 D. The mean follow-up was 12.0 months +/- 5.6 (SD) (range 6 to 37 months). RESULTS: Overall, the mean spherical equivalent decreased 96%, from -11.69 +/- 1.46 D preoperatively to -0.37 +/- 0.80 D postoperatively. The mean astigmatism decreased 72%, from 1.66 +/- 1.22 D to 0.46 +/- 0.53 D. At the last visit, 84.0% of eyes were within +/-1.00 D of emmetropia and 96.4% were within +/-2.00 D. An overcorrection of more than +1.00 D was experienced by 1.8% of patients. The uncorrected visual acuity (UCVA) was 20/20 or better in 45.8% of eyes and 20/40 or better in 89.5%. Six eyes (1.8%) lost 2 or more lines of best corrected visual acuity; this included 1 eye in which iatrogenic keratectasia developed 18 months after LASIK retreatment. Retreatment was done in 37.0% of eyes at a mean of 6.3 +/- 5.3 months (3 to 32 months) after the initial treatment. At the last examination, 86.0% of eyes in Groups A and B and 70.0% in Group C were within +/-1.00 D of emmetropia. A significant difference was found between Groups A and C (P =.032). The UCVA was 20/20 in 52.0% of Group A eyes, 38.0% of Group B eyes, and 23.0% of Group C eyes. The difference between Groups A and C was significant (P =.001), but the difference between Groups A and B was not (P =.055). CONCLUSIONS: In this study, LASIK was effective in correcting myopia up to -14.00 D. The efficacy, predictability, and safety were significantly less in eyes with myopia greater than -14.00 D.

Entropy-driven phase transition in binary mixtures.

Based on the principle of entropy maximum, a transparent method to study the phase separation is proposed. The excluded volume effects of binary mixtures of hard spheres with two different diameters are analyzed and the role of entropy is emphasized. As a result of the entropy variation caused by the packing of large spheres, there is a critical volume fraction to denote the phase boundary. It is shown that the variation of free volume fraction is influenced by the ratio alpha=d(L)/d(S) of large to small sphere diameters and the ratio x=eta(L)/(eta(L)+eta(S)) of large-sphere volume fraction to the total volume fraction of large- and small-spheres. We introduce a modification factor beta to describe the overlap degree of two large spheres excluded volumes when they pack together. The critical volume fractions for large-sphere packing with different values of alpha and x are calculated, and the corresponding phase boundaries are determined. Our results are in quite good agreement with previous experimental measurements.

Results of flap repositioning after laser in situ keratomileusis.

PURPOSE: To determine the incidence and severity of flap folds and displacement after laser in situ keratomileusis (LASIK) and assess the outcome of the flap repositioning procedure. SETTING: Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: Charts of 91 eyes of 87 patients that had flap repositioning were reviewed retrospectively. Four patients had bilateral procedures. RESULTS: The overall rate of flap repositioning was 0.91%. Fifty-six percent of flap folds occurred on the first postoperative day and 85%, within 1 week of the LASIK procedure. The latest flap repositioning was performed 150 days after LASIK. Blurred vision was the main symptom; this occurred in 72% of patients. Eighteen percent of eyes had loose epithelium at the time of LASIK. Dry eye was found in 42% of cases. Nineteen percent of eyes had multiple flap repositioning procedures. Flap folds induced a hyperopic change in refraction and increased astigmatism as well as irregular astigmatism. With the Automated Corneal Shaper(R) (ACS) microkeratome (Bausch & Lomb Surgical), 45% of folds were located in the superior part of the flap and 6% in the inferior part; 42% of folds were oriented horizontally and 17%, vertically; 23% of eyes had a superior gutter. With the Hansatome(R) (Bausch & Lomb Surgical) microkeratome, 73% of folds were central; 87% were oriented vertically and 6%, horizontally. The incidence of flap folds increased to 2.10% with the use of the Hansatome. With a mean follow-up of 8.3 months after flap repositioning (range 3 to 31 months), the uncorrected visual acuity was 20/20 in 59% of eyes and 20/40 in 88%. Three eyes (3%) lost 2 or more lines of best corrected visual acuity. The final spherical equivalent was -0.07 diopter (D) +/- 0.61 (SD), and 87% of eyes were within +/-1.00 D of emmetropia. CONCLUSION: Flap repositioning significantly restored the vision loss caused by flap folds and displacement. However, irregular astigmatism due to permanent residual folds remains the main factor affecting the visual and refractive outcome.

Retreatment after initial laser in situ keratomileusis.

PURPOSE: To report the results of laser in situ keratomileusis (LASIK) retreatment in patients with primary undercorrection and with postoperative regression and to assess the efficacy and safety of LASIK retreatment. SETTING: The Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: The prospective study included 157 eyes of 108 patients. Using the VISX Star laser, retreatments were performed for undercorrection in 43 eyes (27%) and for regression in 114 eyes (73%). The mean follow-up was 15 months (range 6 to 28 months) after the initial surgery and 10 months (range 3 to 25 months) after the repeat LASIK procedure. RESULTS: Overall, the mean spherical equivalent (SE) was -6.11 +/- 2.35 diopters (D) (range -1.87 to -15.00 D) before LASIK and -1.28 +/- 0.57 D (range -0.50 to -3.25 D) prior to retreatment. At the last visit, it was -0.23 +/- 0.41 D (range -2.55 to 1.13 D). One hundred fifty-three eyes (97.5%) were within +/-1.00 D of emmetropia and 128 (81.5%), within +/-0.50 D. The uncorrected visual acuity was 20/20 or better in 68.8% of eyes and 20/40 or better in 98.1%. In all eyes, the best corrected visual acuity (BCVA) improved or remained within 1 line of the pre-revision level. However, 2 eyes (1.3%) lost 2 or more lines of pre-initial LASIK BCVA. Both eyes had a preoperative SE greater than -8.00 D; corneal irregularity was the cause of the decrease in vision. CONCLUSIONS: Several conclusions can be drawn from this study. First, LASIK retreatment is effective and safe for correcting undercorrection and regression after initial LASIK, and a good visual outcome is expected. Second, in most eyes, regression occurs within 6 months after the initial LASIK. However, regression can develop up to 2 years after LASIK. Third, multiple retreatments will be required in some patients. The outcome in these cases is promising.

Interface fluid associated with diffuse lamellar keratitis and epithelial ingrowth after laser in situ keratomileusis.

We report a case in which diffuse interface keratitis began 1 week after bilateral uneventful laser in situ keratomileusis (LASIK). A layer of fluid in the interface with epithelial ingrowth was noted in the left eye 20 days postoperatively. The same complication occurred in the right eye 5 months after LASIK. Dry-eye syndrome and steroid-induced intraocular pressure elevation occurred in this patient with pre-existing ocular hypertension. A long course of interface inflammation was resistant to topical steroids. Surgical removal of the epithelial ingrowth and drainage of the fluid, combined with medical treatment, resulted in resolution of the inflammation. The cytopathologic examination of the fluid showed epithelial cells without signs of inflammation. The clinical features of this case represent a new complication of LASIK.

Hyperopic automated lamellar keratoplasty: complications and visual results.

OBJECTIVE: To examine the long-term safety and efficacy of hyperopic automated lamellar keratoplasty (H-ALK) for correction of primary hyperopia and for consecutive hyperopia following overcorrected myopic refractive surgery. METHODS: A prospective study was done on 67 eyes of 50 consecutive patients who underwent H-ALK between March 17, 1993, and August 18, 1995. Hyperopic automated lamellar keratoplasty was performed for primary hyperopia in 25 eyes (group 1) and for consecutive hyperopia after myopic refractive surgery in 42 eyes (group 2, radial keratotomy, 41 eyes, and myopic automated lamellar keratoplasty, 1 eye). The eyes were followed up for a mean+/-SD of 19.2+/-12.8 months (range, 3-49 months), 58 (87%) of them with 6 months' follow-up, and 45 (67%) of them with at least 1 year's follow-up. Twenty-one eyes were followed up for 2 to 4 years. RESULTS: The overall mean+/-SD preoperative spherical equivalent was +2.87+/-1.28 diopters (D). The mean+/-SD postoperative spherical equivalent was -0.03+/-1.42 D at 3 months, -0.42+/-2.25 D at 6 months, -0.55+/-3.00 D at 1 year, -1.58+/-1.53 D at 2 years, and -0.35+/-1.79 D at the last follow-up. A mean myopic shift of 0.50 D was noted between 3 months and 1 year, and of 1.00 D between 1 and 2 years. Hyperopia was meaningfully reduced and visual acuity was improved by H-ALK, especially for patients with primary hyperopia. Long-term refractive instability, however, is a serious problem with this procedure. In this series, 11 (26%) of 42 eyes in which H-ALK was performed for consecutive hyperopia developed iatrogenic keratoconus. CONCLUSION: Based on this study, the long-term instability of H-ALK and the high incidence of iatrogenic keratoconus following the procedure should discourage its use, especially for consecutive hyperopia following radial keratotomy.

Clear lens extraction to correct hyperopia.

PURPOSE: To evaluate the effectiveness and safety of clear lens extraction with intraocular lens (IOL) implantation to correct hyperopia and to determine the most accurate and predictable method of IOL power selection. SETTING: The Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: The outcome of 20 phacoemulsification and IOL implantation procedures was assessed at a mean follow-up of 23.2 months (range 3 to 60 months). Intraocular lens power and predicted refraction were retrospectively evaluated in each eye with the SRK II and Holladay formulas with different attempted refractions based on the stabilized postoperative refraction. RESULTS: Uncorrected visual acuity (UCVA) improved from 20/200 preoperatively to 20/30 postoperatively. At the final examination, 89% of eyes achieved 20/40 or better UCVA. All eyes had 20/25 or better best corrected visual acuity (BCVA). No eye lost two or more Snellen lines of BCVA. There were no surgical or postoperative complications. The Holladay formula was more accurate than the SRK II formula. With the Holladay formula aiming for -1.00 diopter (D), the predicted mean postoperative spherical equivalent would be -0.21 D +/- 0.89 (SD); with the SRK II aiming for -1.50 D, it would be +0.43 +/- 1.10 D. The Holladay formula reduced the chance of postoperative residual hyperopia. CONCLUSION: Clear lens extraction with IOL implantation was an effective, safe procedure for the correction of hyperopia. However, this method was less accurate and less predictable for hyperopia below +3.00 D. With the Holladay formula aiming for -1.00 D, good visual and refractive results can be expected. Further study with a larger sample of patients and longer follow-up is needed to assess long-term safety and effectiveness.

Intraocular lens power prediction in patients who undergo cataract surgery following previous radial keratotomy.

BACKGROUND: Previous experience has shown that there is no technical difficulty in performing cataract surgery on patients who have previously undergone radial keratotomy. However, some researchers have reported inaccuracy in intraocular lens (IOL) power selection. OBJECTIVES: To assess the visual and refractive outcomes of our patients and to compare different formulas and variables to improve accuracy in power determination. MAIN OUTCOME MEASURES: Ten eyes subjected to phacoemulsification with in-the-bag posterior chamber lens implantation 79 months (range, 36-118 months) after radial keratotomy were evaluated in this study. The IOL power was retrospectively calculated for each eye using the Binkhorst, SRK II, and Holladay formulas with the current keratometry reading, the refractive-derived keratometric value (K), the current refractive-derived K, and the adjusted K. The final refractive result was used as a criterion to judge the accuracy and predictability for each approach. RESULTS: Three eyes underwent an IOL exchange after initial surgery. Among the 7 eyes that did not undergo an IOL exchange, a hyperopic shift that regressed approximately 3 months after surgery occurred in the early postoperative period. At the final examination, 5 of the 7 eyes had a hyperopic error, with 2 eyes showing more than 1.00 diopter (D). Overall, in an average of 27 months (range, 9-80 months) of follow-up, an uncorrected visual acuity of 20/40 or better was obtained in 6 (60%) of the eyes. All 10 eyes had a 20/25 or better postoperative best-corrected visual acuity. The mean (+/-SD) spherical equivalent refraction was changed from -0.78 +/- 3.49 D preoperatively to 0.45 +/- 1.31 D postoperatively. We found that the Binkhorst and Holladay formulas are more accurate than the SRK II formula. With the use of an adjusted K (ie, the current average K minus 1.0 D) in combination with the Binkhorst and Holladay formulas, most of the eyes would achieve a refraction of -2.00 to +0.50 D. CONCLUSIONS: A corneal flattening effect caused by cataract surgery tends to occur in eyes that have undergone previous radial keratotomy. The use of an average between the Binkhorst and Holladay formulas, aiming for -0.75 D with an adjusted K, seems to be a more accurate and predictable method for IOL power calculation. This approach could reduce the chance of postoperative hyperopia.

Prospective evaluation of early visual and refractive effects with small clear corneal incision for cataract surgery.

PURPOSE: To evaluate the early postoperative visual and refractive effects of a 3.25 mm clear corneal self-sealing incision with foldable intraocular lens implantation. SETTING: The Eye Institute of Utah, Salt Lake City. METHODS: Visual acuity and refraction in 50 eyes of 50 consecutive patients having clear corneal phacoemulsification were prospectively evaluated at 30 minutes, 1 day, 1 week, and 1 and 3 months postoperatively. RESULTS: Uncorrected visual acuity of 20/40 or better was obtained in 38% of eyes 30 minutes after surgery, 52% at 1 day, and 89% at 3 months. There was no significant refractive cylinder change (P = .093). Visual rehabilitation and refractive stability were rapid, and induced astigmatism was low. A strong positive correlation was found between refraction at 30 minutes and that at 3 months after surgery (R = .5788, P = .0003). The visual and refractive examination performed 30 minutes after surgery could help early detection of incorrect IOL power selection. CONCLUSION: The low induced astigmatism, excellent early visual acuity, and lack of surgical complications support the concept and justify the use of small temporal corneal incisions for cataract surgery.

Phacoemulsification with intraocular lens implantation in high myopia.

PURPOSE: To assess phacoemulsification and posterior chamber intraocular lens (IOL) implantation in highly myopic eyes and to compare the results of sutureless scleral tunnel incision and sutured scleral incision techniques. SETTING: The Eye Institute of Utah, Salt Lake City. METHODS: A series of 109 highly myopic eyes (axial length over 26.00 mm) were reviewed at a mean postoperative follow-up of 27 months. RESULTS: Postoperative corrected visual acuity was 20/40 or better in 94% of eyes, and uncorrected visual acuity was 20/40 or better in 77% of eyes. Posterior capsule opacification developed in 50% of eyes; 95% of these had neodymium:YAG (Nd:YAG) laser capsulotomy. Cystoid macular edema occurred in two eyes, and one eye developed retinal detachment following Nd:YAG capsulotomy. Eyes that had sutureless scleral tunnel incisions attained earlier postoperative rehabilitation of visual acuity and stabilization of astigmatism than did patients who had sutured scleral incisions. CONCLUSIONS: The results of this study of highly myopic eyes indicate that treating retinal pathology preoperatively and using the sutureless procedure, phacoemulsification, and in-the-bag IOL placement lead to good visual outcome, a lower rate of retinal complications, and a more stable wound.

Initial results of automated lamellar keratoplasty for correction of myopia: one year follow-up.

PURPOSE: To report our initial results with automated lamellar keratoplasty (ALK) to correct myopia and to evaluate the short-term efficacy, safety, and predictability of this procedure. METHODS: A prospective series of 128 eyes of 81 consecutive patients who had ALK were reviewed for a mean follow-up of 13.6 months (range 12 to 19 months). Preoperative data, intraoperative parameters, and postoperative visual acuity, refraction, keratometric readings, and complications at 1 day, 1 week, 1, 3, and 6 months, 1 year, and last follow-up visit were used for analysis. The procedure was performed for myopia in 120 eyes (-4.50 to -13.25 diopters [D]) and for residual myopia following radial keratotomy (RK) in eight eyes (-1.75 D to -3.75 D). A hinged-flap technique was used in 17 cases (13%) once this method was introduced. RESULTS: Preoperative mean uncorrected visual acuity was 0.04 +/- 0.05 (20/500). Postoperatively (12 to 19 months), overall uncorrected visual acuity was 20/40 or better in 86.4% of eyes with a mean uncorrected acuity of 0.68 +/- 0.22 (20/30) 76.2% of eyes were within 1.00 D of emmetropia and 93.6%, within 2.00 D. After the initial ALK procedure, 77% of eyes had RK or astigmatic keratotomy (AK). Among the 29 eyes with ALK alone, 86% had 20/40 or better uncorrected visual acuity, with mean uncorrected acuity and mean corrected acuity of 0.69 +/- 0.21 (20/30) and 0.95 +/- 0.10 (20/21), respectively; 72% of eyes were within 1.00 D of emmetropia and 90%, within 2.00 D. In 4%, astigmatism increased more than 1.00 D from the preoperative value and 4% of eyes (5/128) had persistent irregular astigmatism. Four percent of eyes (5/128) had overcorrection, with a final spherical equivalent greater than +1.00 D. Epithelial growth in the interface requiring surgical removal occurred in 2% of cases. One eye with residual myopia from a previous RK lost the cap after ALK. A homologous donor graft was performed, which resulted in 20/30 uncorrected visual acuity. Best corrected visual acuity of two lines or more was lost in 6.3% of eyes (8/128). This was caused by irregular astigmatism in 63% of cases. CONCLUSIONS: The results of our initial experience indicate that ALK is a reasonably safe, effective, and predictable procedure for correction of high myopia and myopia following previous RK. With additional enhancement with RK/AK, good visual and refractive outcome can be expected.

Long-term stability of refraction after intrastromal suture correction of hyperopia following radial keratotomy.

BACKGROUND: Our first series of nine cases using circular and interrupted sutures for hyperopia from overcorrected radial keratotomy was reported 2 years ago. Additional cases and long-term follow up with this technique are presented here. METHODS: Thirteen eyes of 12 patients with symptomatic hyperopia underwent corneal suturing with pursestring and interrupted sutures and were followed for 3 years. There were six original overcorrections and seven overcorrections after reoperation. The mean preradial keratotomy refractive spherical equivalent refraction was -3.85 +/- 1.40 RESULTS: The mean preoperative refractive spherical equivalent was +2.55 +/- 0.93 D (range +1.125 to +5.375 D). The mean follow up after the suturing procedure was 40 +/- 14.3 months with a range of 10 to 72 months. The change in refraction following suturing procedures averaged -1.84 D, resulting in an overall correction of 72% of the overcorrection. The mean increase of postoperative central keratometric power was 1.42 +/- 0.95 D. All eyes reduction of hyperopia. Uncorrected visual acuity was improved from 0.367 +/- 0.11 (20+60) preoperatively to 0.712 +/- 0.25 (20/30+) postoperatively. The average improvement was 3.3 Snellen lines. using the visual function score to assess the effectiveness of the procedure, we found 85% (11/13) of eyes obtained excellent or good results and 15% appeared fair or poor. In the 3 years since the study began, eight eyes had follow-up data from the previous study and the present study. During this period, an average change of refraction of only -0.19 D was observed. A refractive change less than 0.50 D was observed in 62.5% of the eyes, and all of the eyes had a refractive change within 1.00 D. There were no new complications and no loss of effect during the mean 43 months of follow up for those patients. CONCLUSION: Based on the 3-year follow up, we concluded that intrastromal pursestring and interrupted techniques are stable, safe, and effect procedures for correcting hyperopia following radial keratotomy, especially for less than +3.00 D.

Clear lens extraction for the correction of high refractive error.

The results of clear lens extraction and posterior chamber intraocular lens implantation in 31 eyes with high myopia and six eyes with high hyperopia were reviewed. In the myopic group, 77% of eyes achieved 20/40 or better uncorrected postoperative visual acuity and 97% achieved 20/40 or better corrected acuity. Sixty-eight percent of eyes were within 1.0 diopter (D) of emmetropia and 90% were within 2.0 D. Astigmatic keratotomy (four eyes) and radial keratotomy (one eye) were performed for postoperative refractive errors. Intraocular lens exchange was necessary to correct power in one case. In the hyperopic group, all six eyes achieved 20/40 or better uncorrected postoperative visual acuity and all were within 1.0 D of emmetropia. During the 20-month mean follow-up, no retinal detachment or cystoid macular edema was observed. Posterior capsule opacification was the major complication and it developed faster than reported in other studies.