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Biomedical subjects

J V Aquavella

Publications and source records attributed to J V Aquavella.

At least 19 recordsLinked to original sources
PubMed2001

Corneal sensation after topical anesthesia.

PURPOSE: To compare the topical effects of tetracaine, lidocaine, and bupivacaine on corneal sensitivity in normal eyes. METHODS: Corneal touch sensitivity was measured with a Cochet-Bonnet anesthesiometer before and at 2.5-minute intervals after instillation of the anesthetic agent, until baseline levels had been reestablished. Seventeen healthy volunteers were randomized into five groups. Group 1 included 0.5% tetracaine (n = 6); group 2, 4% lidocaine (n = 8); group 3, 0.75% bupivacaine (n = 8); group 4, 0.5% tetracaine + 4% lidocaine (n = 5); and group 5, 0.5% tetracaine + 0.75% bupivacaine (n = 7). RESULTS: The duration of anesthesia showed no differences between groups 1, 3, and 5. Although there was no difference between groups 2 and 4, both groups demonstrated significantly longer effects than groups 1, 3, and 5 (p < 0.005). CONCLUSION: The application of 4% lidocaine results in a significantly prolonged topical anesthetic effect when compared with tetracaine and bupivacaine.

Adult↗
PubMed1997

Posterior capsule polishing with the neodymium:YLF picosecond laser: model eye study.

PURPOSE: To determine the ability and threshold energy of the neodymium:yttrium-lithium-fluoride (Nd:YLF) picosecond laser to achieve micron-level polishing of a latex posterior capsule facsimile (PCF) as an alternative to laser capsulotomy to treat posterior capsule opacification. SETTING: University of Rochester Medical Center, Rochester, New York, USA. METHODS: A solid-state, mode-locked Nd:YLF picosecond laser was used to polish a latex PCF in contact with a poly(methyl methacrylate) intraocular lens (IOL) in an experimental model eye. Eight study groups were treated at different energy levels ranging from 5 to 15 microJ. All treatments were done at least three times in different latex capsules and lenses. An atomic force microscope was used to measure IOL damage and an interferometric surface analysis microscope to assess the polishing effect on the PCF. The IOLs were further subjected to a scatter analysis to assess the optical significance of the damage produced. RESULTS: The latex PCF revealed a polishing effect with all energy settings used. The IOLs were damaged with all energy settings but 5 microJ. Energy settings higher than 5 microJ caused significantly more polishing effect to the latex and damage to the lenses. At the 10 microJ energy level, a single parameter with no depth produced a relative polishing depth of 3.01 microns +/- 0.10 (root mean square +/- SD). At this energy, the damage to the IOLs was 188 +/- 20.52 nm, and it was associated with typical craters over the surface at regular intervals that corresponded to each individual laser pulse. CONCLUSION: This model documented the feasibility of achieving micron-level precision in excising material with the picosecond laser and showed that posterior capsule polishing should be feasible and safe in human eyes.

Humans↗
PubMed1997

Alcohol versus mechanical epithelial debridement: effect on underlying cornea before excimer laser surgery.

PURPOSE: To determine the effects of 70% isopropyl alcohol used for corneal debridement on surface smoothness, stromal keratocytes, and ease of epithelial removal. SETTING: Cornea Research Laboratory, University of Rochester, and Excimer Laser Laboratory, Genesee Valley Eye Institute, Rochester, New York, USA. METHODS: Rabbit corneas were de-epithelialized mechanically or with 70% alcohol. The rabbits were split into groups and evaluated immediately or after a 50 microns deep excimer laser phototherapeutic keratectomy. All tissue was evaluated and compared in terms of surface smoothness parameters, loss of keratocytes, and inflammatory response to de-epithelialization. RESULTS: Computerized laser interferometric microscopy showed no between-group difference in the surface smoothness parameters. There was a marked absence of keratocytes in the superficial 25% of the corneal stroma. The loss of keratocytes was significantly higher (P < .001) in corneas treated with isopropyl alcohol. The inflammatory response 24 hours after epithelial removal was significantly higher (P < .001) in the corneas treated with alcohol. CONCLUSION: The use of 70% isopropyl alcohol applied for 2 minutes for epithelial removal did not enhance the quality of the subsequent excimer laser procedure. In contrast, isopropyl alcohol increased the inflammatory response, and it may have damaging effects on keratocytes. We would not advocate the use of 70% isopropyl alcohol as administered in our study to remove corneal epithelium before excimer laser surgery.

2-Propanol↗
PubMed1996

Corneal incisions utilizing the 1,053-nm picosecond Nd:YLF ophthalmic laser.

We evaluated the precision and predictability of a 1,053-nm picosecond Nd:YLF ophthalmic laser with various combinations of computer-controlled parameters. We utilized epithelium-free corneal-sclera preparations from NZW rabbits, and the 1,053-nm Nd:YLF laser (Intelligent Surgical Lasers, San Diego, CA, U.S.A.). X-line and line patterns were utilized to make linear corneal incisions. Three parameters (layer size, crossing width, and energy level) were evaluated. One parameter was changed for a total of 120 combinations of computer-controlled parameters. Three incisions were performed for each combination. Although the intended depths of the incisions were constant (300 mu m), the actual depths of the incisions varied with the change of parameters. Increasing layer size decreased the depth of incisions, and increasing crossing width or energy level increased the depth of incisions. Only three of 120 combinations of parameters achieved depths near 300 mu m. Within the same combination of parameters, the depth of the corneal incisions varied. Debris of ablated stromal tissue was observed at the border and partially occupying the incision. Most of the incisions were "funnel"-shaped with the distal treatment zone having a "zigzag" or irregular border. Further improvements are necessary to use this laser system for corneal transverse incisions.

Animals↗
PubMed1996

Analysis of the efficacy and safety of excimer laser PTK in the treatment of corneal disease.

In this study, we report our clinical experiences and results in performing 193-nm argon fluoride excimer laser phototherapeutic keratectomy (PTK) on 48 eyes of 45 patients with various pathology in the anterior one-third of the cornea, including leukoma, stromal dystrophy, anterior basement membrane dystrophy, and Salzmann's nodular degeneration. The VISX model 20/20 laser was used to ablate the anterior stroma to variable depth, dependent upon pathology. Patients were followed for a minimum of 1 year. Per an FDA-approved protocol vision, refraction, comfort, clarity, rate of reepithelialization, and complications were monitored. Seventy-two percent of patients undergoing excimer laser ablation for visual recovery had documented improvement in Snellen acuity. For the same period, 70% of those patients who were symptomatic prelaser were noted to be more comfortable. Corneal clarity improved in 35 of 48 eyes (73%), remained stable in nine (19%), and worsened in four (8%). Complications arose in 8% and included recurrence of herpetic keratouveitis, episcleritis, and an attack of narrow angle glaucoma secondary to cycloplegic agents. Delayed reepithelialization, >7 days, was noted in nine patients (19%). All complications were successfully treated medically. Excimer PTK appears to be a valuable addition to our therapeutic armamentarium for the treatment of superficial stromal opacification and surface irregularity.

Adolescent↗
PubMed1995

Evaluation of tissue adhesives in closure of scleral tunnel incisions.

Using a biomechanical wound strength model, we compared the efficacy of cyanoacrylate and fibrin glues used to close scleral tunnel incisions. Scleral tunnel incisions were made in four groups of rabbits: (1) traditional self-sealing incision, (2) modified non-self-sealing incision, (3) method 2, closed with cyanoacrylate glue, or (4) method 2, closed with fibrin glue. Overall, Groups 1 and 4 showed the least clinical reaction, the slightest decrease in intraocular pressure (which recovered to baseline by day 7), and the most significant recovery of postoperative astigmatism. Initially, the bursting pressure in Groups 1 and 3 was statistically the highest (P < .005). By day 3, wound strengths in Groups 1 and 4 were comparable. Bursting pressure decreased in Groups 2 and 3 by day 7. Our results indicate that clinical responses, intraocular pressure, induced astigmatism, and ultimately wound strength were comparable in fibrin-glue-closed scleral pocket and sutureless self-sealing cataract incisions. Although cyanoacrylate glue cures immediately and initially demonstrates a strong adhesive quality, it causes a severe inflammatory response that inhibits subsequent collagen remodeling. Fibrin tissue adhesives may have an application as adjunctive means of closing scleral tunnel incisions.

Analysis of Variance↗
PubMed1995

Effects of the picosecond neodymium:YLF laser on poly(methyl methacrylate) intraocular lenses during experimental posterior capsulotomy.

We evaluated the effect of the neodymium:YLF picosecond laser on intraocular lenses (IOLs) during experimental posterior capsulotomy and established the minimum damage threshold for lathe-cut poly(methyl methacrylate) (PMMA) IOLs. Single-piece, biconvex, lathe-cut PMMA lenses were placed in a model eye chamber against a latex membrane with a central area of lens-capsule touch. Energy levels from 40 micro J to 360 microJ pulse (0.4 mJ to 3.6 mJ) with a 0.5 mm line and a spot pattern were tested using different focal offsets. Threshold damage level was determined under the scanning electron microscope after observing the minimal energy level that did not cause damage to or pits in the IOLs. Lenses were then analyzed for size and type of damage. The 0.5 mm line pattern at 160 microJ using 350 microns offset was safe and effective for posterior capsulotomy in vitro. spot pattern caused IOL damage in the form of small pits at much lower energy levels of 80 microJ using 400 microns offset than the line pattern.

Lasers↗
PubMed1995

[Correlation between corneal sensitivity and nerve regeneration following excimer laser ablation].

To compare the recovery of corneal sensitivity and corneal regeneration following excimer laser and manual epithelial debridement, the corneal epithelium of the right eye of New Zealand white rabbits (n = 21) was manually debrided and the left eye was ablated with the excimer laser (47 microns depth, 5 Hz, and 160 mJ/cm2). We observed the wound healing rate and corneal sensitivity. The relative density of innervation on the intraepithelial layer was measured using gold chloride staining or right microscopic examination for 30 weeks. In the laser-ablated cornea sensitivity rapidly increased to a normal level by day 5, and then it continued to increase gradually and reached a maximum at day 42. Thereafter it remained elevated to 126 days and returned to normal at 210 days. There were significant differences in the recovery of sensitivity following excimer ablation and manual epithelial removal. The relative density of innervation on the intraepithelial layer after excimer ablation was significantly higher than manual debridement at day 35. We observed a correlation between increased sensitivity levels and increased nerve density. This result suggests that for photorefractive keratectomy or phototherapeutic keratectomy, manual debridement of the corneal epithelium should be performed before stromal excimer ablation.

Animals↗
PubMed1994

Corneal sensitivity and nerve regeneration after excimer laser ablation.

We studied the recovery of corneal sensitivity and corneal regeneration after excimer laser and manual epithelial debridement. The corneal epithelia of right eyes of New Zealand white rabbits (n = 21) were manually debrided and the corneal epithelia of the left eyes were ablated with the excimer laser (47 mm depth, 5 Hz, and 160 mJ/cm2). The relative density of innervation on the intraepithelial layer was measured using gold chloride staining and light microscopy. Wound healing and corneal sensitivity also were observed. Laser-ablated corneal sensitivity increased rapidly to a normal level by day 5, then increased gradually and reached a maximum at day 42. It remained elevated until 126 days, then returned to normal at 210 days. There were significant differences in the recovery of sensitivity after excimer ablation and manual epithelial removal. At day 35, relative density of innervation in the intraepithelial layer treated with excimer laser ablation was significantly higher than that treated with manual debridement. We observed a correlation between increased sensitivity and increased nerve density after excimer ablation. Compared with manual debridement, laser treatment resulted in an increase in networks of axons with terminal endings. This may not be the only factor correlating directly with hypersensitivity after corneal debridement, but it may indicate a quicker recovery route by using a presurgical manual debridement technique.

Animals↗
PubMed1993

Excimer laser keratectomy after radial keratotomy.

Radial keratotomy to treat myopia has been characterized by a lack of predictability. Until recently, patients with undercorrected myopia who were unsatisfied with their visual outcome could only be offered secondary augmentation procedures, which were equally unpredictable. We performed excimer laser keratectomy in six eyes of five patients whose myopia was undercorrected after radial keratotomy. The average residual spherical equivalent refractive error after radial keratotomy was -2.40 diopters, and this was reduced to -0.48 diopters after laser treatment. Final uncorrected visual acuity ranged from 20/80 to 20/20, and visual acuity was corrected to within one line of the preoperative best-corrected value in all patients. Epithelialization of all eyes occurred within four to six days. There were no incidences of corneal neovascularization, including no vascularization of the radial keratotomy incisions. Our findings suggest excimer phototherapeutic keratectomy offers a safe and more controlled method of augmenting undercorrected myopia after radial keratotomy.

Adult↗
PubMed1993

Intraocular lens dislocation in the bag.

We report a case in which an intraocular lens dislocated entirely within the capsular bag. The patient was myopic with a large anterior segment. A standard 5 mm x 6 mm phaco profile intraocular lens was found to be completely dislocated on the fifth postoperative day. The dislocated lens was replaced with another posterior chamber intraocular lens sutured at the ciliary sulcus.

Adult↗
PubMed1993

Surface quality of excimer laser corneal ablation with different frequencies.

To test the effects of different frequencies of a 193-nm excimer laser on the surface smoothness of the ablated materials and the damage to the adjacent structure, four different frequencies (5, 10, 15, and 20 Hz) of a 193-nm excimer laser were used to perform ablations on 20 rabbit corneas and four polymethylmethacrylate blocks at a fluence of 160 mJ/cm2. Each frequency was tested five times on five corneas. The ablated materials were processed and examined with scanning electron microscopy (SEM) and light and transmission electron microscopy (TEM) and a Zygo interference microscope, which quantitatively evaluates the surface smoothness. The results from the Zygo microscope show that there is no statistically significant difference in surface smoothness between any two different frequencies. The SEM reveals similar regularity and uniformity on the ablated surfaces, with no relationship between the laser frequencies and the amount of surface deposits. The TEM demonstrates no correlation between the various frequencies and the thickness of the superficial pseudomembrane and the amount of collateral damage in the adjacent stroma. It appears that the higher frequencies are comparable to the lower one (5 Hz) as to ablation quality, with the benefit of curtailing surgical time and decreasing the chances of eye movement.

Animals↗
PubMed1993

Ambulatory care prospective payment: the effect on clinical practice patterns.

Prospective payment for ambulatory surgical services offers the opportunity to achieve a number of operational efficiencies in the health care delivery system by incorporating incentives for both physicians and facilities to reorganize care. The risk associated with this opportunity is the creation of additional bureaucratic infrastructure.

Ambulatory Surgical Procedures↗
PubMed1993

Nd:YLF laser sclerostomy.

We used a Q-switched Nd:YLF picosecond laser, operating at the 1053-nanometer wavelength with a spot separation of 10 microns and a crossing width of 1000 x 10 microns in a rectangular pattern, to create ab externo sclerostomies in 12 New Zealand white rabbits. The mean energy used was 30 J (range, 24 to 65 J). Filtering blebs were observed for 1 week, with a concurrent drop in intraocular pressure. Histology performed at days 3, 10, and 30 revealed clean-cut sclerostomies, with minimal thermal and mechanical damage.

Animals↗
PubMed1993

Endogenous endophthalmitis caused by Escherichia coli.

Endophthalmitis is a rare complication of Escherichia coli-induced septicemia. Nine cases of endogenous endophthalmitis caused by E. coli have been reported previously, all except one in patients with diabetes. The most common primary site of infection is the urinary tract. The course of illness is rapidly progressive with a poor visual prognosis. Concurrent systemic morbidity, including body abscesses and endocarditis, is high. We report an additional case of endogenous endophthalmitis from E. coli in a diabetic woman. Enucleation was required despite aggressive topical and systemic treatment. The pertinent literature is reviewed.

Adult↗