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At least 73 records · Page 4Linked to original sources
PubMed2006

Biocide uptake in contact lenses and loss of fungicidal activity during storage of contact lenses.

PURPOSE: With recent outbreaks of Fusarium keratitis related to contact lens wear, studies were conducted to determine the biocide uptake during lens storage, and the resulting effect on antifungal activity of related products. METHODS: ACUVUE 2 (etafilcon A) soft, hydrophilic contact lenses (group IV) were soaked from 1 hour to 7 days in OPTI-FREE Express and OPTI-FREE RepleniSH multipurpose disinfecting solutions with POLYQUAD (polyquaternium-1) and ALDOX (myristamidopropyl dimethylamine) biocides and multipurpose solutions, Bausch & Lomb ReNu with MoistureLoc (Alexidine), ReNu MultiPlus (polyhexamethylene biguanide [PHMB]), and AMO Complete MoisturePLUS (PHMB). Storage solutions were tested to evaluate the effect of preservative uptake on the residual biocide activity against Fusarium solani. RESULTS: Approximately 30% to 60% of the PHMB and Alexidine were depleted by 6 hours, with comparable loss of antimicrobial activity. Decreasing activity was noted with corresponding decreases in active concentration throughout the course of the evaluation. The POLYQUAD systems retained nearly 100% of the biocide and fungicidal activity and maintained their concentration in the solution. CONCLUSIONS: OPTI-FREE Express and OPTI-FREE RepleniSH multipurpose disinfecting solutions maintained fungicidal efficacy after storage of lenses. The Alexidine- and PHMB-based multipurpose solutions tested showed significant uptake of preservative into group IV lenses, resulting in a decrease in the residual activity of the storage solution. The POLYQUAD systems showed a low uptake of biocide and maintained fungicidal efficacy against F. solani.

Antifungal Agents↗
PubMed1980

Isolation and identification of biologically active contaminants from soft contact lenses. I. Nicotine deposits on worn lenses.

A method for elution of contaminants deposited onto soft contact lenses during wear utilizing a nondestructive cleaning procedure is presented. Twenty-five soft contact lenses supplied by American Optical Corp. were pooled and subjected to 20% H2O2 (hydrogen peroxide). The resulting wash was extracted with organic solvents, hydrolyzed, and re-extracted. The organic-soluble fraction was further divided into strong acids, intermediate acids, neutrals, and bases. Sequential separation, isolation, characterization, and confirmation of constituents were achieved with thin-layer chromatography, ultraviolet spectrophotometry, and microcrystallography. Photomicrographs before and after cleaning were obtained to assess the optical quality of the lenses. Initial emphasis has been to characterize naturally occurring, biologically active constituents and common environmental toxins of molecular weight 150 to 500. We find that nicotine, a common environmental pollutant and a significant component of the blood of people who smoke regularly, is one of the contaminants present on a worn soft contact lens.

Chemistry, Organic↗
PubMed1994

[Complications after implantation of anterior chamber lenses. An analysis of 4,100 explanted intraocular lenses].

In this study we analyzed the incidence and types of complications seen after cataract surgery and implantation of anterior chamber intraocular lenses (AS-IOLs). This report is based on a review of 4104 explanted AC-IOLs that were submitted to the Center for IOL Research over the past 10 years. The results from pathological examinations were correlated with clinical information. Of the 4104 IOLs, 50% were closed-loop designs (n = 2095/4104), and 22% were open-loop lenses (919/4104). The IOLs most frequently explanted were the closed loop designs Leiske (n = 847) and Stableflex (n = 808). The most important reason for explantation was corneal pathology. Closed-loop IOLs had a much higher complication rate than open-loop lenses. Flexible open-loop AC-IOLs showed the highest explantation rate during the first postoperative year due to surgical problems. The complication rate of closed-loop AC-IOLs increased with implant duration and were responsible for 80% of the corneal pathology. Flexible open-loop AC-IOLs can be an alternative for secondary or exchange implantation. Furthermore, they could also be a viable alternative for cataract surgery in developing countries in order to help catch up with the overwhelming backlog of cases that exist there.

Aged↗
PubMed1996

A 3-year prospective study of the clinical performance of daily disposable contact lenses compared with frequent replacement and conventional daily wear contact lenses.

PURPOSE: To determine the clinical performance of daily disposable contact lens wear compared to conventional daily wear contact lenses and frequent replacement contact lenses. METHODS: This 3-year prospective study was conducted in 12 U.S. practices. Of 338 eligible subjects enrolled (126 conventional daily wear, 144 frequent replacement, and 68 daily disposable), 229 subjects disposable group were compared with the conventional daily wear group and two sub-groups of frequent replacement subjects: (a) those with replacement at 2-weak intervals and (b) those with replacement at 1 or 3 months. RESULTS: Comparing the daily disposable and conventional daily wear groups, the daily disposable subjects were more likely to be asymptomatic, reported fewer symptoms of redness, cloudy vision and grittiness/dirty sensation, reported better vision and overall satisfaction, and had fewer lens surface deposits, complications, tarsal abnormalities, and unscheduled visits, while conventional daily wear subjects reported better lens handling. Comparing the daily disposable and frequent replacement (1/3 months) groups, daily disposable subjects reported fewer symptoms of foreign body sensation, redness, cloudy vision and grittiness/dirty sensation, reported better subjective vision, comfort and overall satisfaction, and has fewer lens surface deposits, complications, and tarsal abnormalities, while frequent replacement (1/3 months) subjects reported fewer dryness symptoms and better lens handling. Comparing the daily disposable and frequent replacement (2-weeks) groups, daily disposable subjects reported better subjective vision and overall satisfaction and had fewer lens surface deposits and tarsal abnormalities, while frequent replacement (2-weeks) subjects reported fewer photophobia symptoms. CONCLUSIONS: The results indicate that daily disposable wear may be the most trouble-free way of wearing contact lenses.

Adult↗
PubMed1997

The use of disposable contact lenses as therapeutic lenses.

PURPOSE: To evaluate the efficacy of Acuvue contact lenses as a therapeutic contact lens in 33 patients with noninfectious corneal disorders. METHODS: We fit 33 patients (21 female, 12 male) with Acuvue contact lenses. Patients were seen in follow-up at 24 hours, 4 days, 15 days, and then monthly. Contact lenses were replaced weekly. Ocular signs and symptoms related to lens tolerance were recorded at each follow-up visit. RESULTS: Twenty-six patients (79%) improved or remained asymptomatic. Seven patients (21%) were discontinued due to complications, intolerance, or poor fit. In the majority of patients (79%), the Acuvue lens was tolerated and was beneficial in the treatment of corneal disease. CONCLUSIONS: The Acuvue contact lens can be effectively utilized as a therapeutic contact lens.

Adolescent↗
PubMed2001

Inversion and isomerization of Asp-58 residue in human alphaA-crystallin from normal aged lenses and cataractous lenses.

We have previously shown that L-Asp-151 in alphaA-crystallin from the human lens is converted to the biologically uncommon D-isomer. This process was not simple racemization, but stereoinversion, accompanied by isomerization to form the beta-Asp residue, such that L-beta-Asp, D-alpha-Asp and D-beta-Asp were formed. The present study shows that Asp-58 of human alphaA-crystallin is also converted to the D-isomer to a high degree to form the same isomers with age. The D/L ratio of beta-Asp-58 in aged normal lens increased to more than 3.0, showing stereoinversion by the 60 year range, then decreased to 1.0 in the 80 year range, while the isomerization of Asp-58 increased in the 80 year range. We also measured inversion and isomerization of the same residue from cataractous and normal human lenses of the 60 year range. The D/L ratio of Asp-58 from cataractous lenses was significantly lower than that from normal lenses, while the isomerization at Asp-58 in cataractous alphaA-crystallin was significantly higher than that of normal alphaA-crystallin. These results indicate that isomerization to the beta isomer of Asp-58 in cataractous alphaA-crystallin increased more than inversion to the D-isomer, suggesting that there are changes in the native structure of alphaA-crystallin in the human cataractous lens.

Adult↗
PubMedDate not supplied

Transscleral suture fixation and anterior chamber intraocular lenses implanted after removal of posteriorly dislocated crystalline lenses.

The surgical technique is described for simultaneous removal of posteriorly dislocated crystalline lenses and implantation of anterior chamber (AC) or scleral fixation posterior chamber (PC) intraocular lenses (IOL) using pars plana vitrectomy. Twenty-two patients underwent this complex operation. Observation time ranged from 2 to 10 months (mean 5 months). Best-corrected post-operative visual acuity was 1.0 in half the patients in the AC group (n = 12), and in 80% of the PC group (n = 10). It was less than 0.5 in 25% of cases in the AC group whereas all PC patients had visual acuity 0.5 or better. In nine cases with pre-operative ocular hypertension, post-operative intraocular pressure became normal, although topical glaucoma therapy was necessary in three patients in the AC group and in one from the PC group. No severe complications were found. Removal of posteriorly dislocated crystalline lens using pars plana vitrectomy and limbal incision is a safe procedure. Simultaneous AC or transscleral PC lens implantation is a good alternative to contact lenses. Visual rehabilitation was good in both groups of patients, although post-operative visual acuity was better after PC transscleral fixation than after AC surgery.

Adult↗
PubMed1983

Na,K-ATPase in simulated eye bank and cryoextracted rabbit lenses, and human eye bank lenses and cataracts.

In the rabbit, cryoextraction of the lens and subsequent storage in Tyrode's solution did not alter the Na,K-ATPase activity from that determined in immediately excised rabbit lenses. Similarly, the procedures employed with the rabbit eye to simulate collection and storage of normal human eyes (eye banking) had no effect upon the Na,K-ATPase activity of the lens. These results permitted the investigation of human lenses with the knowledge that measured Na,K-ATPase activity had not been altered grossly by any manipulation procedures. Analysis of Na,K-ATPase activity in 44 eye bank lenses, 14 primary nuclear cataracts, 11 primary cortical cataracts, 18 primary posterior subcapsular cataracts, and 31 mixed cataracts revealed no significant difference in the enzyme activity between these groups. Similarly, there was no correlation between electrolyte levels and Na,K-ATPase in a further 18 mixed cataracts. It is concluded that, despite an often pronounced electrolyte imbalance, human cataract can develop without significant alteration in Na,K-ATPase activity.

Adenosine Triphosphatases↗
PubMed1993

Complications and symptoms in disposable extended wear lenses compared with conventional soft daily wear and soft extended wear lenses.

We conducted a historical cohort study of 2,433 cosmetic contact lens wearers (1,055 conventional [non-disposable] daily wear lens users, 905 disposable extended wear lens users, and 473 conventional extended wear lens users) in order to estimate the rates of occurrence of complications and symptoms among disposable extended wear contact lens users and compare these rates with those for conventional soft daily wear users and conventional soft extended wear users. Data were abstracted from the office records of eight eye care practitioners for the period February 1987 through April 1989. The prevalence of all complications for disposable extended wear lens users was not significantly different from the prevalence for conventional daily wear lens users but was significantly lower than the prevalence for conventional extended wear lens users. The incidence of ulcers among disposable extended wear lens users did not differ significantly from the incidence found with conventional extended wear, but was significantly higher than the rate for conventional daily wear. Disposable extended wear lenses, in contrast to conventional extended wear lenses, may be more strongly associated with benign peripheral infiltrates than with the more serious central ulcers. Disposable extended wear lens users reported symptoms less frequently at routine scheduled visits than both conventional daily wear and conventional extended wear users and had a lower rate of unscheduled visits for complications and symptoms.

Adult↗
PubMed2001

[Scanning electron microscopic study of 12 lenses of two types of soft acrylic intraocular lenses].

BACKGROUND: Evaluation of the surface properties of two models of one-piece foldable acrylic intraocular lenses (IOLs) before and after folding and passing the IOLs through an injector. METHODS: We studied two foldable IOL models made of a polymethacrylate/2-hydroxyethylmethacrylate copolymer: EasAcryl 1(R) (Chiron) and Raysoft(R) 547H (Rayner). Twelve IOLs of each design with different diopters were examined. Light and scanning electron microscopy were performed before and after IOL folding and passing the IOLs through a Micra G103 injector (Chiron Adatomed) and an IC-2BU inserter cartridge (Chiron Microsert II). RESULTS: All IOLs presented a homogeneous surface and smoothly finished edges of haptics and optics. The inner edges of all IOL haptics and the optic edges of some IOLs had ridges at high magnifications. No IOL demonstrated any folding defects of the optic such as a folding line or scratches. Three of 16 folded IOLs showed defects or cracking of the IOL haptics due to incomplete placement in the inserter cartridge. CONCLUSIONS: The two models of soft acrylic intraocular lenses showed excellent surface quality. After folding and injection process no alteration of the optics was detected in any of the IOLs. However, the IOLs need careful placement in the inserter cartridge to avoid haptic damage.

Acrylates↗
PubMed1993

[Pseudo-accommodation of diffractive multifocal lenses and monofocal lenses].

35 patients were examined for their pseudoaccommodation 6 to 18 months after cataract extraction and implantation of a diffractive multifocal intraocular lens (MIOL). While in 15 patients a MIOL had been implanted in both eyes 20 patients had a MIOL in one eye only. 45 type 3M 815 LE and 5 3M 825 XE lenses were implanted. The mean age was 58.2 years +/- 9.6 years (33 to 76). Only patients without any pathology except cataract and preoperative refractive errors < +/- 5 diopters of spherical and +/- 1 diopter of astigmatic refraction were eligible for implantation of MIOLs. After estimation of the objective and subjective refraction the patients' pseudoaccommodation was measured by testing their visual acuity, adding lenses of +/- 1, 2, 3, 4, 5 diopters to their best distance correction. All patients with MIOLs reached a visual acuity of 0.4 or better with a maximum peak at 0 and -3 diopters. The visual acuity of the MIOL patients was significantly better in the range of -1 to -4 diopters compared to the results of a control group of patients with monofocal IOLs. This suggests a wider range of pseudoaccommodation in patients with MIOLs.

Accommodation, Ocular↗
PubMed1994

Penetrating keratoplasty and intraocular lens exchange: open-loop anterior chamber lenses versus sutured posterior chamber lenses.

Penetrating keratoplasty with intraocular lens (IOL) exchange is generally recommended for eyes with pseudophakic bullous keratopathy, especially when the keratopathy is associated with uveitis, chronic cystoid macular edema, or a uveitis-glaucoma-hyphema syndrome. Review of the literature has shown basically equivalent long-term results of penetrating keratoplasty and IOL exchange using both Kelman-style, flexible, open-loop anterior chamber lenses and acapsular fixation of sutured posterior chamber lenses. The use of suture-fixated posterior chamber IOLs appears warranted in centers where the surgeon has extensive experience with this specific technique and in cases with special indications, for example, in eyes with extensive angle abnormalities. However, because this technique is more difficult to perform, and in the absence of such preexisting contraindications, for most practices we do not hesitate to recommend the use of a Kelman-style anterior chamber lens during routine cases of penetrating keratoplasty and IOL exchange.

Anterior Chamber↗
PubMed2005

Linear deposits on the surfaces of intraocular lenses implanted through a hexagonal cartridge which mimic scratches/cracks on the lenses.

AIM: To describe unique linear deposits on the surface of posterior chamber intraocular lenses (IOLs) occurring after implantation through a hexagonal cartridge. METHODS: Five ACR6D SE IOLs (Corneal Laboratories, Pringy, France) were injected/implanted through hexagonal cartridges. Two of these were injected into a petri dish and the remaining three were inserted into the evacuated capsular bag of cadaver eyes. In addition, three other ACR6D SE IOLs were injected into a petri dish through round cartridges. The latter served as controls. RESULTS: All lenses that were injected/implanted through the hexagonal cartridges demonstrated linear deposits on the posterior surface of the IOL optic component. The IOLs that were injected through the round cartridges had no deposits. All the hexagonal cartridges showed signs of internal cracking. None of the round cartridges were cracked. CONCLUSION: Implantation of at least one IOL model, the ACR6D SE IOL, through a hexagonal cartridge can result in linear deposits on the posterior optical surface of the IOL. The shape of the cartridge appears to be a significant factor in causing the depositions.

Artifacts↗
PubMed2000

Duplication of unique optical effects of ancient Egyptian lenses from the IV/V Dynasties: lenses fabricated ca 2620-2400 BC or roughly 4600 years ago.

Ancient (in fact, first known) lenses (ca. 4600 years ago) mainly from the IVth and Vth Dynasties of Egypt had truly remarkable and unique optical properties. These were parts of equally fascinating eye structures. These structures were fabricated as separate assemblies for insertion into funerary statues during certain brief windows of time (roughly from 2620-2400 BC, and 1750-1700 BC). These "eyes" appear to follow the observer as he/she rotated in any direction about these statues. In this paper, by simple means, we have recreated the optical properties of these unique lenses in the laboratory in order to help understand their special properties.

Egypt, Ancient↗
PubMed1992

Early postkeratoplasty astigmatism following placement of anterior chamber lenses and transsclerally sutured posterior chamber lenses.

Intraocular pseudophakic correction during penetrating keratoplasty (PK) for aphakic or pseudophakic bullous keratopathy may be achieved either with anterior or posterior chamber lenses. Posterior chamber lenses can be fixed to the iris or sclera in eyes lacking adequate posterior capsular support. Post-PK astigmatism can delay early visual rehabilitation of the patient. We reviewed the last 15 patients at our institution who had undergone PK and anterior chamber lens placement for bullous keratopathy. These were compared to the last 15 patients who had undergone PK and transsclerally sutured posterior chamber lens placement. Patients who had placement of a flexible anterior chamber lens at time of PK had a mean astigmatism of 6.73 D at the last visit before any sutures were removed. There was no predominant axis of astigmatism or relationship of the axis of astigmatism to the meridian of lens placement. Patients with placement of a transsclerally sutured posterior chamber lens at time of PK had a mean astigmatism of 5.18 D at the last visit before any sutures were removed. Mean astigmatism was not significantly different (P greater than 0.05) from that seen with anterior chamber lens placement. In the majority of patients the axis of post-PK astigmatism was oriented perpendicular to the meridian of the transsclerally sutured posterior chamber lens.

Aged↗
PubMed1993

A clinical evaluation of frequent replacement contact lenses on patients currently wearing premium reusable daily wear soft contact lenses.

A 3-month clinical investigation was undertaken to evaluate a population of premium reusable daily wear soft contact lens wearers when refitted with soft contact lenses worn on a daily wear schedule and replaced every 2 weeks. In addition to an initial visit, follow-up visits occurred at 2-, 4-, 8-, and 12 weeks. Areas of assessment included vision, lens fitting performance, ocular physiology, subjective comfort and handling responses and lens surface deposits and damage. Of the 51 patients recruited, 50 were successfully trial fit and enrolled. During the course of the investigation, all subjects utilized a multipurpose care regimen without the addition of an enzymatic cleaner. Upon conclusion of the investigation, 75.0 percent of the subjects chose to continue wearing the study lenses on a 2-week frequent replacement basis.

Adult↗
PubMed2004

Identification and functional clustering of global gene expression differences between age-related cataract and clear human lenses and aged human lenses.

We have examined the gene expression profiles of young, old and cataractous human lenses in order to differentiate those gene expression changes specific for cataract from those also associated with lens aging. Differentially expressed transcripts were identified by oligonucleotide microarray analysis and clustered according to their known functions. Four hundred and twelve transcripts that are increased and 919 transcripts that are decreased were identified at the 2-fold or greater level between epithelia isolated from cataract relative to clear lenses while 182 transcripts that are increased and 547 transcripts that are decreased were identified at the 2-fold or greater level between young and old lens epithelia. Comparison of the cataract gene expression changes with those detected in lens aging revealed that only 3 transcripts exhibited similar trends in gene expression. These data suggest that cataract- and age-specific changes in gene expression do not overlap and provide evidence for multiple cataract- and age-specific gene expression changes in the human lens.

Aged↗
PubMed2001

Clinical performance of polynomial lenses versus tri-curve lenses. II: ocular responses.

This study, which was a continuation of the previous one, aimed to determine the subjective and objective responses after wearing polynomial and tri-curve rigid gas permeable (RGP) lenses over a period of 6 months. Subjects were divided into two groups, each of which wore either one of these lens designs and 17 of 22 subjects completed the 6-month study. Subjective responses were assessed by a questionnaire while the objective responses including vision, contrast sensitivity, lens fitting and the corneal integrity, corneal thickness and endothelial cell morphology were assessed by the examiner. There were no significant differences in the subjective ratings, vision, contrast sensitivity and the lens fitting between the two groups. Except for the p-value (p) and the apical radius (r(o)) along the steepest meridian and the coefficient of variation in cell size in the inferior corneal endothelium, there were no significant changes in the palpebral aperture size, the p-value and r(o) along the flattest meridian, corneal thickness and the other endothelial cell variables after the 6-month study period. The poor success and high dropout rates of RGP lens wear in this study stress the importance and need for further investigations of such lenses.

Journal Article↗