The CLAO journal : official publication of the Contact Lens Association of Ophthalmologists, Inc最新文献

Purpose: To evaluate whether dry-eye symptoms are associated with epitheliopathy of that portion of the upper eyelid marginal conjunctiva-the lid wiper-that wipes the ocular, or contact lens surface, during blinking.

Methods: Subjects were divided into two groups based on the presence or absence of dry-eye symptoms. The lid wiper of asymptomatic (n=75) and symptomatic (n=30) soft contact lens wearers was examined, following the instillation of fluorescein and rose bengal dyes. Lid-wiper staining was graded zero to 3.

Results: Eighty percent of the symptomatic subjects displayed lid-wiper staining compared to 13% of the asymptomatic subjects. The difference in staining between the two groups was significant (P<0.0001). Of the symptomatic subjects, 20% showed no staining; 26.6%, grade 1 staining; 36.6%, grade 2; and 16.6% showed grade 3 staining. Of the asymptomatic subjects, 87% exhibited no staining; 9%, grade 1 staining; 3%, grade 2; and 1% showed grade 3 staining.

Conclusions: This study describes a new clinical condition, lid-wiper epitheliopathy, an alteration of the epithelium of that portion of the marginal conjunctiva of the upper eyelid that wipes the ocular surface, diagnosed by staining with fluorescein and rose bengal dyes.

Purpose: The purpose of this study is to assess the effects of long-term contact lens wear on corneal thickness and to compare differences based on rigid versus soft lens material.

Methods: This analysis included scanning slit topographic imaging (Orbscan, Bausch & Lomb, Rochester, NY) performed on 124 consecutive patients (248 eyes), who underwent comprehensive evaluations in consideration of refractive surgery by one surgeon.

Results: Sixty-two 62 patients (124 eyes) who had not previously worn contact lenses had a least-squares mean pachymetry of 546.4 microm +/-3.5 SE. Thirty-nine patients (78 eyes) who had previously worn soft contact lenses for an average of 16 years had a least-squares mean pachymetry of 543.2 microm +/-3.8 SE. Twenty-three patients (46 eyes) who had worn rigid contact lenses for an average of 19 years had a least-squares mean pachymetry of 509.4 microm +/-6.9 SE. Mean pachymetry differed significantly between eyes wearing rigid lenses versus no lenses (P<0.0001) and between eyes wearing rigid lenses versus soft lenses (P=0.0002).

Conclusion: Long-term rigid contact lens wear is associated with a decrease in the average central-corneal thickness (CCT) by an average of 37 microm, in this group of otherwise healthy eyes, compared to no contact lens wear. Long-term soft contact lens wear did not appear to significantly change corneal thickness compared to no contact lens wear. Caution should be exercised when screening patients with a history of long-term rigid contact lens wear for possible excimer-laser photoablative correction.

Purpose: To report a case of electrical shock resulting in multiple ocular manifestations, including anisocoria, acute bilateral iritis, bilateral cataracts, and macular cyst formation, and to provide a review of the literature on electrically induced ocular injuries.

Methods: Case report and review of the literature.

Results: The case presented demonstrates a sequential occurrence of anisocoria, bilateral cataract formation, iritis, and macular cyst formation, with resolution following medical and surgical treatment.

Conclusions: Electrically induced injuries can have many ocular manifestations that may occur simultaneously or sequentially, occasionally occurring later than the inciting event. The most common ocular finding is cataract formation.

Purpose: To report a case of Mycobacterium chelonae keratitis associated with soft contact lens wear.

Methods: A 17-year-old boy who wore frequent replacement soft contact lenses developed keratitis in the right eye. There was no history of trauma to the right eye. The patient was treated initially with topical ciprofloxacin but without improvement. On presentation, visual acuity in his right eye was 20/40. A Gram-stained scraping of the corneal infiltrate revealed beaded filamentous rods, and the organisms were acid-fast positive. The patient's right eye was treated with intensive topical amikacin, 20 mg/mL, and 10 % sulfacetamide. Eventually, Mycobacterium chelonae was cultured on Sabourard's agar, topical sulfacetamide was stopped, and amikacin was continued.

Results: The patient's keratitis responded well to amikacin and resolved over a period of 4 weeks. Visual acuity in the right eye improved to 20/25.

Conclusions: Mycobacterium chelonae is a rare cause of keratitis in soft contact lens wearers. We have identified fewer than five cases of Mycobacterium chelonae keratitis associated with soft contact lenses in the literature. Prompt and accurate diagnosis of the organism using comeal scraping can lead to appropriate therapy and resolution of the keratitis.

Purpose: To evaluate the resolution of contact lens-induced corneal warpage before keratorefractive surgery.

Methods: We prospectively studied the eyes of 165 consecutive contact lens-wearing patients evaluated for keratorefractive surgery. Significant contact lens-induced corneal warpage was detected by comeal topography in 20 eyes of 11 patients. Manifested refraction, keratometry, and cornea topography were subsequently recorded during weekly or biweekly reevaluations and were compared with previous measurements for stability. Effects of age, sex, type, and duration of contact-lens wear and the recovery time period to stabilization were analyzed.

Results: Overall, a 12% incidence of significant contact lens-induced corneal warpage was found. In patients demonstrating lens-associated warpage, the mean duration of prior contact lens wear was 21.2 years (range 10 to 30 years); lens use included daily wear soft (n=2), extended-wear soft (n=6), toric (n=4), and rigid gas-permeable contact lenses (n=8). Up to 3.0 diopter (D) refractive and 2.5D keratometric shifts accompanied by significant topography pattern differences were observed. The average recovery time for stabilization of refraction, keratometry (change within +/- 0.5D), and topography pattern was 7.8+/-6.7 weeks (range 1 to 20 weeks). Recovery rates differed between the lens types: soft extended-wear 11.6+/-8.5 weeks, soft toric lens 5.5+/-4.9 weeks, soft daily wear 2.5+/-2.1 weeks, and rigid gas-permeable 8.8+/-6.8 weeks.

Conclusion: We observed a 12% incidence of significant contact lens-induced corneal warpage in patients undergoing evaluation for keratorefractive surgery. Warpage occurred with all types of contact lens wear but resolved at different rates. To optimize the quality and predictability of keratorefractive procedures, an appropriate waiting period is necessary for contact lens-induced corneal warpage to stabilize. We suggest that resolution of corneal warpage be documented by stable serial manifested refractions, keratometry, and corneal topographic patterns before scheduling patients for keratorefractive surgery.

Purpose: This article reports a case in which Thygeson's superficial punctate keratopathy was treated with photorefractive keratectomy (PRK) combined with phototherapeutic keratectomy (PTK).

Methods: A 20-year-old white woman in good health who had a 2-year history of Thygeson's superficial punctate keratopathy in both eyes was evaluated for refractive surgery to treat myopia. The patient had experienced multiple recurrences of the Thygeson's during the preceding 2-year period. Previous treatment had consisted of topical steroids with good response to therapy but recurrences once the topical therapy was stopped. After discussing different options, the patient underwent uncomplicated PRK-PTK for treatment of her myopia, and her postoperative course was uneventful.

Results: Eight months after undergoing PRK-PTK, the patient has excellent uncorrected visual acuity (20/20 in both eyes) and has experienced no recurrences of Thygeson's superficial punctate keratopathy.

Conclusions: Successful treatment of Thygeson's superficial punctate keratopathy in a patient with a low myopia may be achieved with the use of combined PRK-PTK procedures.

Purpose: To investigate the tear-film osmolarity of contact lens wearers for different types of contact lenses.

Methods: Fifty six eyes of 56 cases were evaluated in four different groups according to the type of contact lens worn, with 14 eyes in each group. Groups 1 and 2 consisted of subjects who wore frequent-replacement daily wear soft contact lenses; group 1 lenses had 55% water content, and lenses in group 2 had 38% water content. Groups 3 and 4 consisted of subjects who wore rigid gas-permeable contact lenses, with a Dk value of 90 in group 3 and a Dk value of 52 in group 4. Tear-film osmolarity values in milliosmole (mosm) units were determined by auto-osmometer (Orstat 6030, Daiichi Kagacu, Kyoto, Japan) before and after contact lens wear for each group, and the results were compared statistically by ANOVA test.

Results: Before the period of contact lens wear, the tear-film osmolarity values of group 1, 2, 3, and 4 were 283.61+/-12.83 mosm, 285.23+/-8.94 mosm, 285.57+/-11.39 mosm, and 280.15+/-12.07 mosm, respectively. After the period of contact lens wear, these values were measured at 312.15+/-16.03 mosm in group 1, 316.54+/-12.14 mosm in group 2, 313.14+/-9.66 mosm in group 3, and 316.38+/-11.60 mosm in group 4. Although the difference between the values before and after the period of contact lens wear was statistically significant for each group (F=291.45; P=0.0005), there was no statistically significant difference among the groups.

Conclusions: When a contact lens is placed in the eye, the lens alters the normal structure of the tear film and affects its rate of evaporation; therefore tear-film osmolarity may increase. In our study, all contact lenses produced a similar effect on tear-film osmolarity.

Purpose: Mucin balls appear to cause spherical indentations in the corneal epithelium during silicone hydrogel extended contact lens wear. The purpose of this report is to describe and quantify these spherical indentations, as examined in the human cornea by in vivo confocal microscopy and by in vitro immunocytochemistry in the rabbit cornea.

Methods: Confocal images of full-thickness corneal epithelium were taken from three human patients participating in a 1-year extended contact lens-wear trial. Diameter and depth of the indentations were determined and measured. Two rabbit corneas showing identical indentations were stained with propidium iodide (nuclear stain) and Ki-67 (proliferation marker) and were examined using a laser scanning confocal microscope.

Results: The diameter of the spherical indentations is largest on the epithelial surface, ranging from 33.9 to 78.8 microm. Indentations form spherical sections whose depth variably extends into the corneal epithelium, reaching as far as the basal lamina. The rabbit model showed no epithelial nuclei within the indentation. Furthermore, stromal cells localized immediately beneath the indentations were positive for Ki-67 (proliferation).

Discussion: Spherical indentations of the corneal epithelium induced by mucin balls appear to be gaps or holes that can extend deep into the corneal epithelium. Indentations may potentially open a pathway for infectious microorganisms to penetrate the cornea. Surprisingly, stromal cells immediately beneath the holes were stimulated to proliferate, and there seemed to be an increase in localized cell density.

Purpose: To determine apical radius, surface asphericity, and horizontal visible iris diameters (HVID) in normal subjects and to find out which has the greatest influence on the corneal sagittal depth.

Methods: Videokeratoscopic data were analyzed to determine the apical radius and the p-value of the near horizontal principal meridian for 73 right and 77 left eyes. The HVID also were measured.

Results: Scatterplots of sagittal depth versus apical radius, p-value, and HVID indicated the strongest association between the sagittal depth and the HVID.

Conclusions: Normal variations in corneal asphericity have the least influence whereas normal variations in HVID have the greatest influence in changing the corneal sagittal depth. The most appropriate measurement to take to select the optimum soft contact lens specification may be the HVID.

Purpose: This article compares measurements of corneal thickness obtained with the Orbscan Topography System with those obtained with the ultrasonic pachymeter, when used to measure central-comeal thickness in normal subjects.

Methods: Slit-scan topography (Orbscan II system, version 3.0, Bausch & Lomb, Rochester, NY) and ultrasonic pachymetry (Ophthasonic A-Scan/ Pachometer III, Accutome, Malvern, PA) were used to measure central-corneal thickness in 92 right corneas of 92 healthy adult subjects. A correlation analysis was used to evaluate the relationship between both instruments. Measurements were also compared by plotting the difference between the methods against the average. The hypothesis of zero bias was examined by a paired t-test. The 95% limits of agreement also were calculated.

Results: The mean corneal thickness was 559.9 microm +/-3.73 SEM with the Orbscan system and 551.2 microm +/- 4.57 SEM with the ultrasonic pachymeter, values that were significantly different (paired t-test, P = 0.000). The coefficient of determination was 0.860 (y = -65.78 + 1.135 x; P = 0.000). The mean difference between the measurements from both devices was found to be significantly different from zero (mean: 8.74 microm; paired t-test; P = 0.000), with Orbscan being slightly higher than the Ophthasonic A-Scan.

Conclusions: The Orbscan system measurements of central corneal thickness were greater than ultrasonic pachymeter measurements, a difference that was statistically significantly.