Microbiological study of disposable soft contact lenses after photorefractive keratectomy.

PURPOSE: To evaluate the bacterial contamination of bandage disposable soft contact lenses used in patients following photorefractive keratectomy (PRK) and to correlate our findings with clinical data. METHODS: Forty-six patients (81 eyes) underwent PRK. Immediately after each procedure, disposable soft contact lenses were positioned with sterile forceps. After 3 days, the lenses were removed in a sterile manner, placed in sterile Eppendorf pipettes containing 8 mL of enriched brain heart infusion broth, and analyzed for microbial contamination. RESULTS: Seven positive cultures were found: six gram positive cocci (7.4%) and one gram negative bacillus (1.2%). There was no clinical correlation with these findings. CONCLUSION: Isolated microorganisms were similar to those described in the literature as agents of bacterial keratitis and are components of the normal ocular flora. Klebsiela pneumoniae--considered an occasional or transient flora--was the exception. All isolated microorganisms but K. pneumoniae were sensitive to most of the antibiotics tested. Our findings suggest that the risk of infectious keratitis after PRK related to soft contact lens wear for 3 days seems to be low, which may be because lenses were not manipulated by the patient during the wearing period, and the postoperative antibiotic regimen was strictly followed by patients. However, care should be taken to instruct patients in proper lens care practices to reduce the risk of bacterial keratitis in contact lens wear following PRK.     

Contact lens wear after photorefractive keratectomy: comparison between rigid gas permeable and soft contact lenses.

PURPOSE: To determine if rigid gas permeable (RGP) or soft contact lenses can be successfully worn after photorefractive keratectomy (PRK) to correct residual refractive errors. METHODS: Patients with residual stable ametropia after PRK were fit with RGP or soft lenses. Manifest refraction, corneal topography, and keratometry were performed, and post-PRK corneal haze was graded during the study visits. Contact lens fit characteristics and comfort were assessed. Lens centration, visual quality, and ocular surface status were graded, and visual acuity with contact lenses was charted. RESULTS: Eighteen patients were recruited for RGP lens fitting. The mean refractive error post-PRK was +0.80 D +/- 2.03 (range: -3.50 to+3.00 D). The mean contact lens power was -3.90 D +/- 2.03 (range: 0 to -7.00 D), and the mean contact lens base curve was 7.88 mm +/-0.16. A significant positive tear film at the site of the central ablation was noted, contributing to excessive minus lens power in all cases. Despite mild to moderate lens instability and de-centration, 14 patients reported excellent visual quality with the lenses, and pre-PRK best-corrected acuity was achieved in all patients. Twenty-five percent (4 of 16) of the patients were able to wear the lenses all day. Eleven patients were recruited for soft contact lens fitting-five from the RGP trial. The mean refractive error post-PRK was -0.64 D +/- 2.01 (range: -3.50 to +1.75D). The mean contact lens power was -0.60 D +/- 2.07 (range: -3.75 to +2.5 D), and the mean contact lens base curve was 8.33 mm +/- 0.42. Eight patients were corrected with lenses to their pre-PRK best-corrected acuity, and nine patients reported excellent visual quality with the lenses. All the patients had excellent lens centration. Thirty-six percent (four of 11) of patients were wearing the lenses all day. CONCLUSIONS: Fitting RGP lenses after PRK results in good visual acuity but may be associated with mild to moderate lens instability and decentration. Soft contact lens fitting also results in good visual acuity. Soft lenses were better tolerated by the subjects in our study because of improved lens centration and stability.     

Contact lens fitting after photorefractive keratectomy.

AIMS/BACKGROUND: This study evaluated contact lens fitting and the longer term response of the photorefractive keratectomy (PRK) cornea to lens wear. In PRK for myopia problems such as regression, anterior stromal haze, irregular astigmatism, halo aberration, and anisometropia have been reported. Certain patients therefore require contact lens correction to obtain best corrected visual acuity (BCVA). METHOD: From an original cohort of 80 patients, 15 were dissatisfied with their visual outcome 6 months after PRK. Ten of these were fitted with lenses and monitored regularly. RESULTS: The best fit rigid gas permeable lens of diameter 9.20-10.00 mm was generally 0.10 mm steeper than mean keratometry readings. Because of lid discomfort five patients were refitted with daily wear soft lenses. All 10 achieved satisfactory lens wear of 10 hours per day. Central corneal steepening of 0.75 D (0.15 mm) occurred in one patient. Two patients had slight central corneal flattening. Three patients discontinued lens wear as they found lens care a nuisance. Four finally opted for retreatment by PRK. CONCLUSIONS: In most cases, contact lenses gave good visual acuity and, in cases of mild irregular astigmatism, a significant improvement over spectacle BCVA. No significant adverse reaction to contact lens wear was found. Although ocular tolerance of lenses was satisfactory, several patients discontinued lens wear or sought improved unaided vision.     

Comparison of the effect of removing bandage contact lens on the days 3 and 5 following photorefractive keratectomy

International Ophthalmology -     

Effects of lotrafilcon A and omafilcon A bandage contact lenses on visual outcomes after photorefractive keratectomy

PURPOSE: To evaluate postoperative healing between bandage contact lenses with high and low oxygen permeability in patients having photorefractive keratectomy (PRK). SETTING: Center for Refractive Surgery, Walter Reed Army Medical Center, Washington, DC, USA. METHODS: This retrospective study compared patients receiving a high-oxygen-transmission bandage contact lens (Focus Night & Day [N&D], Ciba Vision; n = 92) and those receiving a low-oxygen-transmission lens (Proclear, Cooper Vision; n = 114) after PRK. Visual outcomes, safety, and efficacy were assessed postoperatively at 1, 4, and 7 days and 1, 3, 6, and 12 months. RESULTS: Overall pain scores were higher in the Proclear group at 1 day (P = .000) and 4 days (P = .027). The N&D group had an increase in corneal infiltrates at 4 days (P = .025) and 1 week (P = .017). At 1 month, 40.4% of patients in the Proclear group and 18.6% in the N&D group had a 1 or more line decrease in best spectacle-corrected visual acuity (BSCVA) (P = .002). Although there was a trend toward a higher haze rate in the Proclear group, it was not statistically significant (P = .064). There was no statistically significant difference in uncorrected visual acuity, goal of emmetropia, contrast sensitivity, or reepithelialization. CONCLUSIONS: The N&D lens produced less pain and better postoperative results in terms of haze and BSCVA at 1 month. However, it led to a higher incidence of corneal infiltrates. There was no difference between the lenses in the end result at 12 months.     

准分子激光屈光性角膜切削术后高透氧性角膜接触镜的应用

目的:探讨高透氧性角膜接触镜对准分子激光屈光性角膜切削术(photorefractive keratectomy,PRK)后眼刺激症状及角膜上皮愈合的影响。方法:共95例190眼PRK病例,术后随机选择一只眼戴软性亲水性高透氧的角膜接触镜,另一只眼配戴普通月抛型角膜接触镜。术后记录术眼自觉症状,观察角膜上皮愈合情况,检查术后6mo裸眼视力,同时进行haze评分。结果:高透氧角膜接触镜组术眼视物模糊、眼痛、畏光均轻于普通月抛型角膜接触镜组,两组比较差异有统计学意义(P<0.05)。高透氧角膜接触镜组平均角膜上皮愈合时间分别为3.11±2.12d,普通月抛型角膜接触镜组为4.02±2.21d,两组比较差异有统计学意义(P<0.05)。角膜上皮72h内愈合者高透氧角膜接触镜组占46%,普通月抛型角膜接触镜组占36%。术后第7d裸眼视力高于1.0者高透氧角膜接触镜组为60眼(63%),普通月抛型角膜接触镜组为48眼(51%)。术后6mo两组术后裸眼视力无显著性差异(P=0.35),两组haze发生率比较无显著性差异(P=0.55)。结论:PRK术后使用高透氧性角膜接触镜可以明显减轻术后患者的角膜刺激症状,减少患者的术后不适感,缩短角膜上皮的愈合时间。     

Intraocular lens power calculation after decentered photorefractive keratectomy

A 56-year-old patient who had pliotorefractive keratectomy (PRK) to correct highunilateral myopia developed a progressive nuclear cataract.. Phacoemulsification an and , intraocular lens (IOL) implantation were performed: However,: determination of IOL power using automated keratometry and computerized videokeratography was not successful il in this case of high axial myopia because of a decentered ablation zone, resulting in too-steep keratometric readings: Postoperative hyperopia could only be corrected by an IOL exchange. Because it may not be possible to determine the exact keratometric values for IOL calculation after PRK,: subtracting the change in refraction induced by PRK from the preoperative keratometric readings, might have been more accurate in this patient.     

Masked comparison of silicone hydrogel lotrafilcon A and etafilcon A extended-wear bandage contact lenses after photorefractive keratectomy

PURPOSE: To compare the efficacy of 2 types of bandage contact lenses (BCLs) after photorefractive keratectomy (PRK). SETTING: Navy Refractive Surgery Center, Naval Medical Center San Diego, San Diego, California, USA. METHODS: In this prospective study, 100 patients received PRK in both eyes. Each patient received a BCL composed of etafilcon A (Acuvue [ACV], Vistakon Inc.) (14.0 diameter, 8.4/8.8 base curve) in 1 eye and lotrafilcon A (Focus Night & Day [N&D], Ciba Vision) (13.8 diameter, 8.4/8.6 base curve) in the fellow eye. The patient was masked to the lens type in each eye. The postoperative medication regimen was the same with both lenses. The epithelial defect size and subjective level of discomfort were measured at surgery and daily after surgery until both eyes had reepithelialized and the lenses were removed. RESULTS: The mean epithelial defect size at surgery was similar with both BCLs (ACV 57.07 mm(2) and N&D 57.53 mm(2); P=.422). On postoperative days 1 and 2, the mean defect size was significantly smaller in eyes with the N&D lens (day 1, ACV 21.53 and N&D 18.74; day 2, ACV 3.62 and N&D 2.12) (paired t test, P<.001). On day 1, no eye had completely reepithelialized; on day 2, 20 eyes with N&D lenses and 13 eyes with ACV lenses had. On day 3, 70 eyes with N&D lenses and 66 eyes with ACV lenses had reepithelialized. The mean discomfort index was significantly higher in the eyes with ACV lenses on days 1 and 2 (paired t test, P<.001 and P<.002, respectively). Topical nonpreserved tetracaine was used significantly more often in eyes with ACV lenses on days 1, 2, and 3 (paired t test, P<.001, P<.008, P<.003, respectively). No correlation between the use of tetracaine in the first 24 hours and the rate of reepithelialization was noted (R(2)=0.0025 for ACV and R(2)=0.0003 for N&D). CONCLUSION: The lotrafilcon A lens resulted in significantly faster corneal reepithelialization and reduced patient discomfort in most patients during the first 48 hours after PRK.     

Factors that influence patient choice of contact lens or photorefractive keratectomy

OBJECTIVE: To explore characteristics of patients and factors that influence their decision in selecting photorefractive keratectomy (PRK) and contact lenses. METHODS: A questionnaire was presented to 255 PRK and 240 contact lens patients, covering patient demographics, refraction, reasons for choosing PRK or contact lens, and advice from clinicians or friends/relatives. RESULTS: Mean patient age was 37 years for PRK and 26 years for contact lens (P < .0001). The magnitude of the mean spherical equivalent refraction in the better eye was 4.14 D for PRK and 3.26 D for contact lens. Advertising influenced 36% (n = 92) of PRK compared to 17% (n = 41) of contact lens patients. In the PRK group, 52% (n = 133) opted for PRK based on cost; in the contact lens group the cost of PRK was thought to be high by 68% (n = 163). Eighty-four percent (n = 214) of the PRK group were contact lens wearers; of these, 32% (n = 68) were intolerant to contact lenses and 13% (n = 28) were intolerant to lens care solutions. Fifty-six percent (n = 134) of the contact lens group were concerned about the long-term effects of PRK and 49% (n = 118) were afraid to undergo a surgical procedure. CONCLUSIONS: PRK patients were significantly older but had only marginally higher refractive error than contact lens patients. Many patients appeared to discontinue contact lens use due to tolerance problems.     

Topical thiotepa treatment for recurrent corneal haze after photorefractive keratectomy

PURPOSE: To describe the use of topical thiotepa in the treatment of recurrent haze after photorefractive keratectomy (PRK). SETTING: Gimbel Eye Centre, Calgary, Alberta, Canada. METHODS: Five patients with recurrent haze after myopic PRK were retreated with phototherapeutic keratectomy and topical thiotepa. Before retreatment, the best corrected visual acuity (BCVA) ranged from 20/40 to 20/200. Follow-up ranged from 3 to to15 months. RESULTS:Haze, uncorrected visual acuity (UCVA), and BCVA improved in all patients. Three eyes had a UCVA of 20/20(-2) or better and a BCVA of 20/20(-1) or better. The other 2 eyes experienced regression of the myopia and astigmatism and had a BCVA of 20/25(-1) or better. CONCLUSION: Topical thiotepa appeared to be an effective treatment for recurrent corneal haze following myopic PRK.     

准分子激光屈光性角膜手术后白内障人工晶状体植入术

目的探讨准分子激光屈光性角膜手术后白内障吸出术中、植入人工晶状体的屈光度计算方法。方法对4例（4眼）准分子激光屈光性角膜手术后的白内障行超声乳化吸出及人工晶状体植入术，术前采用OrbscanⅡ角膜地形图及角膜曲率计测量角膜的K值，分别应用第二代经验公式（SRKⅡ）计算所需人工晶状体的屈光度。术后验光记录术眼屈光状况，与术前结果对比，评价所选择的人工晶状体屈光度的准确性。结果OrbscanⅡ角膜地形图和角膜曲率计分别测量的角膜K值，以及所计算的人工晶状体的屈光度，均有明显的差别。尽管按预留近视状态，选用角膜地形图测量的K值计算人工晶状体的屈光度，术后仍然欠矫，平均产生远视＋1．57D，较术前预留度数仍相差约＋3．44D。结论采用OrbscanⅡ角膜地形图的K值来计算人工晶状体屈光度误差小，在预留的屈光度数基础上加3．50D来选择人工晶状体是较为精确和安全的。     

Reverse geometry contact lens wear after photorefractive keratectomy, radial keratotomy, or penetrating keratoplasty

PURPOSE: To determine if a super diffusion coefficient of lens/lens thickness (Dk/L) reverse geometry gas permeable (steep peripheral and flatter central curve) contact lenses can be successfully worn after excimer photorefractive keratectomy (PRK), radial keratotomy (RK), or penetrating keratoplasty (PK). METHODS: Patients with residual ametropia after PRK, RK, or PK were fitted with reverse geometry lenses (Plateau lens in SF-P material; Menicon USA, Inc, Clovis, CA, U.S.A.). Contact lens fit characteristics and comfort were assessed. Lens centration, visual quality, and ocular surface status were graded and visual acuity charted. RESULTS: Thirteen eyes of 11 patients were fitted; eight eyes with PRK, one eye with RK, and four eyes with PK previously performed. The mean follow up of the patients was six months. The visual acuity prior to lenses ranged from 6/12 to counting fingers, and the acuity with lenses ranged from 6/6 to 6/30. Eight of the 11 patients wore the lenses the whole day without problems; 3 patients discontinued lens wear due to discomfort or unsatisfactory vision. CONCLUSIONS: The combination of super Dk/L and reverse geometry lenses facilitate lens wear and is associated with good visual acuity.     

Hollow bandage contact lens

OBJECTIVE: To report on the use of a new bandage contact lens (BCL) for a leaking filtering bleb. PATIENTS AND METHODS: A hollow BCL, with an internal central opening of 6 mm, has been applied on three eyes that had leaking blebs shortly after either trabeculectomy or combined cataract extraction and trabeculectomy, each with a fornix-based conjunctival flap. RESULTS: The treatment with this lens was found beneficial: the leakage subsided and the patients were comfortable with the lens. The internal hollow of the BCL enabled us to monitor the intraocular pressure throughout the entire follow-up period without transient and repeated removal of the BCL. CONCLUSION: The new hollow BCL was found efficacious. The study suggests that this lens may have advantages over the commonly used BCLs that are related to the elimination of the need for its frequent removal and reinsertion for tonometry. This decreases the risk of both the exposure of the lens and the filtering bleb to contamination and the interference with the continuity of the process of conjunctival epithelial closure.     

Intraocular lens power calculations using corneal topography after photorefractive keratectomy

PURPOSE: To report the preoperative and postoperative palpebral fissure width in eyes undergoing laser in situ keratomileusis.METHODS: In a prospective study, 165 consecutive eyes of 87 patients (41 men and 46 women with a mean +/- standard deviation age of 32.9 (+/-9.5) years) had laser in situ keratomileusis using a Summit (Waltham, MA) APEX PLUS excimer laser and a Moria (Antony, France) LSK microkeratome. The width of palpebral fissure was measured preoperatively, 3 months or 6 months after laser in situ keratomileusis. Patients were classified into three groups as follows: hard contact lens users group (n = 61), soft contact lens users group (n = 63), and non-contact lens users group (n = 41).RESULTS: The average width of palpebral fissure increased after laser in situ keratomileusis in all three groups. The hard contact lens users group increased from 7.6 (+/-1.6) mm to 8.7 (+/-1.2) mm (P <.0001) and non-contact lens users group increased from 7.7 (+/-1.9) mm to 8.9 (+/-1.9) mm (P <.0001).CONCLUSION: These results suggest that laser in situ keratomileusis may be associated with an increase in the width of the palpebral fissure.