Biomedical subjects
Publications and source records attributed to M A Galin.
A patient with hyperopia and accommodative esotropia was implanted bilaterally with hyperopic angle-supported refractive implants. Control of the esotropia was achieved as was some improvement in fusional ability. After three years, the endothelium remains healthy, the eye is quiet and control of the esotropia is maintained.
Adhesion of staphylococcal cells to intraocular lenses coated with heparin was studied under in vitro flow conditions (280 microl min(-1)) at 37 degrees C. The intraocular lenses were incubated with human cerebrospinal fluid for 1 h or with cerebrospinal fluid including 0.50% plasma for 12 h, prior to bacterial challenge. Two strains of Staphylococcus epidermidis selected for this study, were isolated from biomaterial-associated infections. Bacterial adhesion was quantitated by bioluminescence and visualized by fluorescence microscopy of acridine orange stained bacteria. Surface coating with heparin significantly decreased bacterial adhesion of both strains after incubation with cerebrospinal fluid including 0.50% plasma for 12 h (p = 0.0209). However, no difference in bacterial adhesion was obtained between intraocular lenses with and without heparin, after incubation with cerebrospinal fluid for 1 h (p = 0.327). Microscopy showed that more bacteria were present on intraocular lenses without heparin than on intraocular lenses with heparin. The results show that preincubation with a proteinaceous fluid influences subsequent bacterial adhesion to the polymer surface. The results suggest that IOLs with heparin coating may be less prone to bacterial adhesion under perfusion conditions after surface conditioning in human CSF with 0.50% plasma and a preincubation period of 12 h. Heparin coating might be a valuable tool to decrease implant-associated bacterial endophthalmitis.
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We have compared long-term intraocular pressure control in patients with open angle glaucoma, cupping and atrophy of the optic nerve head and visual field loss as well as cataract after: trabeculectomy posterior to the scleral spur and cataract extraction without implantation in 108 patients. guarded posterior lip sclerectomy, cataract extraction and Mark VIII or Mark IX anterior chamber implantation in 28 patients. argon laser trabeculoplasty followed by lens extraction and implantation in 27 patients. Approximately 75 per cent of patients achieve intraocular pressures of 18 mm Hg or less without medication after (a), and approximately 40 per cent of patients achieve similar control without medication after (b). Approximately 25 per cent of these glaucoma patients have intraocular pressure levels of less than or equal to 18 mm Hg on topical medication three months after ALT, and none achieve this control without medication. Cataract surgery with anterior or posterior chamber implantation caused loss of topical control in four of the seven patients benefiting from ALT. These data imply that combined surgery with or without implantation produces better and more significant intraocular pressure control than the presently utilized techniques of ALT subsequently followed by lens extraction and implantation.
Seventeen cases of open-angle glaucoma requiring cataract extraction underwent intracapsular cataract extraction, trabeculectomy posterior to the scleral spur, and MK9 intraocular lens insertion. Approximately 50 per cent of the patients achieved intraocular pressures of 18 mm Hg or less without medication two years later. Though implantation reduces the surgical success of the combined operation, it is safe, easy to perform and does not worsen pre-operative levels of intraocular pressure and/or control.
We measured the effects of pH changes after water washings of polymethylmethacrylate (PMMA) intraocular lenses sterilized in 10% sodium hydroxide (NaOH). Whereas inserting the base-sterilized lens directly into the eye causes a large pH change in the local area of the implant, three separate washings of the NaOH-treated implant in 15 ml of water eliminates this change. No buffer is required.
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A retrospective study of 104 eyes that had iris-supported Sputnik intraocular lenses implanted and no surgery in the fellow eye and a separate series of 30 implanted eyes whose second eyes underwent surgery but did not receive implants disclosed that endothelial cell densities in the eyes with implants decreased immediately after surgery and then continued to decrease at the same rate as those of the control eyes. There was no sudden decrease in the endothelial cell counts during follow-up periods ranging from three to seven years. The main cause of large cell losses immediately after surgery, and possibly long-term corneal decompensation, was surgical manipulation rather than the presence of this style of intraocular lens.
Uncomplicated placement of an intraocular lens at the time of routine cataract extraction is associated with a greater inflammatory response than simple lens extraction. We have shown that certain components of prosthetic intraocular lenses are capable of activating the complement system in human serum in such a fashion as to generate peptides capable of mediating acute inflammatory reactions. Normal human serum was incubated with intraocular lenses in vitro and then examined for cleavage products of C3 and C5 and for C5-derived chemotactic activity for human polymorphonuclear leukocytes. Polymethylmethacrylate lenses with nylon and polypropylene loops were found to be capable of causing cleavage of C3 (detected by crossed immunoelectrophoresis) and C5 (detected by single-dimension radioimmunoelectrophoresis) as well as generation of C5-derived chemotactic activity in human serum. Serum incubated with polymethylmethacrylate lenses without loop supports exhibited no such activity. Results of our studies indicate that certain nylon- and polypropylene-looped intraocular lenses are not "inert" biologically and may elicit acute inflammatory reactions.
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Pupillary block glaucoma is a potential complication of implantation. Early recognition and prompt medical therapy will generally successfully treat the condition. In some instances surgical treatment is required if medical therapy is inadequate. Laser iridectomy and laser photomydriasis are other alternatives to surgical therapy. This case reports successful treatment of pseudophakic pupillary block glaucoma using laser photomydriasis.
Seventy-five percent of patients with open-angle glaucoma and cataract will not require medication at the 2-year period after a cyclodialysis canaliculo-trabeculectomy cataract extraction; this is in contrast to simple cataract extraction, which has a success rate of approximately 12 percent. The absence of significant morbidity and the predictability of the procedure recommend it for all patients with open-angle glaucoma needing cataract extraction, not simply those with inadequate glaucoma control.
Nylon 66 and polypropylene are chemotactic in human serum while PMMA from intraocular lenses is not. Chemotactic activity is unaltered by Ridley, 5 per cent NaOH, or ethylene oxide sterilization. Chemotaxis is but one manifestation of an overall inflammatory process that may be involved in implant-induced corneal and retinal dysfunction.
Polymethylmethacrylate intraocular lenses were left in 10% NaOH or 10% KOH for various periods of time. Contact angles were unaltered and electron spectroscopy for chemical analysis was unchanged. This concentration of alkali does not appear to chemically change the lens surface during the study period.
A population of 250 age-matched cataract patients was studied to determine if hospitalization was required for cataract extraction. The success of the procedure was not jeopardized if immediate ambulation was effected and postsurgical care carried out entirely on an ambulatory basis in a nonhospital environment. The cost containment potential of this approach cannot be readily achieved in the face of existing regulatory systems and insurance requirements.
Tissue cultures of secondary rabbit kidney cells were grown in maintenance medium containing varying concentrations of methylmethacrylate monomer from 5% to 0.05%. No pathologic changes were observed in those tissue cultures containing 0.1% or less monomer as compared to controls. Data from previous studies on the rate of elution of monomer from polymethylmethacrylate and from published studies of aqueous humor dynamics indicate that the monomer level in intraocular lenses will be less than the concentration toxic to living cells in tissue culture.
The Ridley method for intraocular lens sterilization employs 10% NaOH for one hour followed by long-term storage in 0.1% NaOH. Ten percent NaOH for one hour was found to be ineffective when 106 B. subtilis spores were used for study in the presence of a looped lens system. A three-hour period was found to be effective. Similar concentrations of organisms were not killed by 0.1% NaOH even after 30 days. Consequently, the standard Ridley method would be inadequate for looped lens systems and would not fulfill the requirements for terminal sterilization. Teh percent NaOH for three hours would appear to be an acceptable terminal sterilization method.
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