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Biomedical subjects

F W Price

Publications and source records attributed to F W Price.

53 records · Page 3Linked to original sources
PubMed1988

A controlled method of removing the Stableflex lens.

It has been reported that the Stableflex lens, marketed by Optical Radiation Corporation, can be difficult to remove if one is not experienced with the procedure and the special characteristics of the lens. A new method, using the lens haptics as an aid in its removal, is described. This method is relatively atraumatic if the surgeon is familiar with the tendency of Stableflex lens loops to erode deeply into ocular tissues. Careful controlled amputation of the loops is necessary before the remaining portion of the loop is gently removed from tissue encapsulation.

Humans↗
PubMed1987

Scarring of a recipient cornea following epikeratoplasty.

A recipient cornea gradually developed wrinkling and opacification in Bowman's layer following an uneventful myopic epikeratoplasty. The process continued after removal of the lenticule, and the best corrected visual acuity decreased from 20/20 to 20/60. Glare, especially at night, severely compromised the vision in this eye. Six months after removal of the lenticule, a homoplastic myopic keratomileusis was performed to remove the corneal opacity and correct the residual myopia. Morphologic analysis of the patient's excised cornea demonstrated wrinkles and folds in Bowman's layer. To our knowledge, this is the first reported case of scarring of a patient's own cornea after epikeratoplasty and of treatment of a failed epikeratoplasty with homoplastic myopic keratomileusis.

Adult↗
PubMed1987

Localized endophthalmitis: a newly described cause of the so-called toxic lens syndrome.

We report five cases of post-extracapsular cataract extraction infection in which subsequent pathologic analyses identified the organisms and found the infection to be localized or confined to the lens capsular sac. The most common offending organisms were gram-positive pleomorphic bacilli. In one case, we were able to identify the bacteria as Propionibacterium acnes. We designate this condition a localized endophthalmitis. It should be considered any time a persistent, smoldering, postoperative inflammation occurs, and in the differential diagnosis of phacoanaphylactic endophthalmitis. The condition itself is not new, but undoubtedly many such cases have gone unrecognized or have been misdiagnosed as the so-called toxic lens syndrome. In localized endophthalmitis, a clinically visible inflammatory process may occur even when multiple diagnostic taps are negative, although when the cases first appeared, the surgeons were not aware of the entity and anaerobic cultures were not always obtained. A negative tap may be explained by the fact that metabolic products from the organisms are released from the bag into the anterior segment and vitreous. A synergistic reaction may occur between these organisms and retained lens cortical remnants that may cause or exacerbate a hypersensitivity reaction. The condition may be worsened by Nd:YAG capsulotomy. The pathogenesis of localized endophthalmitis has nothing to do with the type of intraocular lens fixation (lens capsular sac or ciliary sulcus); rather, the simple presence of a capsular sac after extracapsular cataract extraction is the prerequisite for the clinical condition.

Aged↗
PubMed1980

Bilateral acute retinal necrosis.

A 20-year-old woman lost all useful vision over a 2 1/2-month period as a result of a necrotizing and occlusive vasculitis of the retina. Treatment with prednisone, immunosuppressants, and aspirin was unsuccessful. No systemic manifestations of the disease were found and no cause was discovered. Kodachromes and fluorescein angiograms showed the progression in one eye from normal to near total retinal necrosis. The process began with a mild venous dilation and peripheral arteritis that progressed into an obliterative vasculitis with abrupt vessel dilation, hemorrhages, and retinal swelling. This was followed by necrosis and sloughing of the retina into the vitreous. Vitreous contraction and necrotic retina produced unrepairable retinal detachments.

Adult↗
PubMedDate not supplied

Corneal tissue levels of topically applied ofloxacin.

PURPOSE: To evaluate the levels of ofloxacin (Ocuflox) in human corneal tissue in patients exposed to various dosing regimens and application methods. SETTING: Corneal Consultants of Indiana, Indianapolis, Indiana, USA. METHODS: Forty patients meeting inclusion criteria were recruited from persons scheduled to have penetrating keratoplasty (PKP). Patients were placed into one of two study groups of 20 each based on dosing regimen and application method. The SAS GLM (General Linear Models) procedure was used to test for differences in mean Ocuflox tissue concentration among study groups and for interaction effects of preoperative diagnosis, trephine size, dosing regimen, and corneal integrity. RESULTS: Corneal tissue concentrations of Ocuflox were elevated significantly by varying drug application methods and dosing schedules before PKP. Eyes receiving medication every 15 minutes for 4 hours had significantly higher levels of Ocuflox than those receiving the drug in six doses over 24 hours before surgery. Ocuflox concentrations exceeded the MIC90 (minimum inhibitory concentration) for key ocular pathogens in essentially all cornea specimens studied. CONCLUSION: Ocuflox penetration was improved by administering it in a controlled setting at 15 minute intervals over 4 hours. The drug provided high tissue levels in both the cornea and aqueous humor, which together with its broad range of antibacterial coverage, should make it a good choice for prophylactic treatment.

Administration, Topical↗
PubMedDate not supplied

Bilateral penetrating autokeratoplasty.

BACKGROUND: Corneal transplantation is an important modality for treatment of a variety of degenerative, congenital, and traumatic disorders. Despite great advances in surgical techniques, postoperative care, and eye banking over the past 20 years, corneal graft rejection continues to be a substantial risk to successful outcome. METHODS: We describe a series of three cases in which the clear cornea from a blind eye was used to replace an opaque cornea on a fellow eye with known visual potential and the abnormal cornea was transplanted on the blind eye. Mean follow up was 74 months (range, 66 to 84 months). All three patients had concurrent glaucoma at presentation, and one had a highly vascularized cornea. RESULTS: Spectacle-corrected vision improved in all cases postoperatively. However, one patient had a non-immune graft failure 58 months after surgery. CONCLUSIONS: The use of autologous tissue avoids the risk of allograft rejection after penetrating keratoplasty and eliminates the need for long-term postoperative corticosteroids which may exacerbate pre-existing glaucoma. In selected patients, autokeratoplasty can be a useful technique, especially if heavy corneal vascularization or pre-existing glaucoma is present.

Aged↗
PubMedDate not supplied

Automated lamellar keratomileusis in situ for myopia.

BACKGROUND: Keratomileusis in situ, particularly automated lamellar keratoplasty, is a commonly performed technique of keratomileusis in the United States. METHODS: A single center consecutive series of 152 eyes undergoing keratomileusis in situ for myopia was analyzed. Spherical equivalent refractions were compared before and after surgery. The standard nomogram supplied with the automatic corneal shaper (Chiron Vision Corp, Irvine, Calif) was used. The mean of preoperative myopia treated was -9.30 +/- 3.10 diopters (D) (range, -5.12 to -22.75 D). RESULTS: Of the 144 eyes with 1 month follow up, 30 (21%) were within 0.50 D of the planned correction at 1 month, 54 (38%) were within 1.00 D, and 97 (67%) were within 2.00 D. At 6 or more months follow up, 51 of 68 eyes (75%) achieved uncorrected visual acuity of 20/40 or better and 13 of 68 (19%) 20/20 or better when eyes with macular degeneration and amblyopia were removed. Forty-six of 78 eyes (59%) with 6 months or greater follow up required retreatment procedures to correct residual myopia or astigmatism. Multiple regression analysis explained 40% of the variation between attempted correction and postoperative results. An overall 5% shift of refraction in the myopic direction occurred between 1 and 6 months. Of the 110 eyes with both 1- and 3-month examinations, the spherical equivalent refraction changed between these time intervals by 1.00 D or more in 54 (49%) eyes; and 11 (31%) eyes changed by 1.00 D or more between the 3- and 6-month examinations. Although 6% of eyes lost 2 or more lines of spectacle-corrected visual acuity, 11% gained 2 or more lines. CONCLUSION: Myopic keratomileusis in situ using the automated lamellar keratoplasty technique appears to be a safe and most effective procedure to reduce moderate to high myopia. However, the predictability of the procedure needs improvement.

Adolescent↗
PubMedDate not supplied

Central islands of corneal steepening after automated lamellar keratoplasty for myopia.

BACKGROUND: Central steep islands are a phenomena of videokeratography that demonstrate local central steepening within a larger diameter area of the cornea treated by refractive surgery that removed stromal tissue to reduce myopia. This report details four cases in which central steep islands occurred following automated lamellar keratoplasty (keratomileusis in situ). METHODS: A total of 43 automated lamellar keratoplasty procedures were performed on 32 patients between January 1993 and September 1993. Central islands were identified using video-keratography. RESULTS: Out of 43 cases of automated lamellar keratoplasty, central steep islands developed in six eyes of four patients. These steep areas developed within a few weeks after surgery; increases in the elevation of these islands correlated with recurring myopia. Slit-lamp microscopy revealed no epithelial surface abnormalities or difficulties with the interface of the resection. A central steep island did not prevent excellent uncorrected visual acuity. After subsequent refractive keratotomy for residual myopia, central steep islands either regressed or disappeared. CONCLUSION: Central islands of corneal steepening may occur after automated lamellar keratoplasty for myopia. The etiology is unknown.

Automation↗
PubMedDate not supplied

Arcuate transverse keratotomy for astigmatism followed by subsequent radial or transverse keratotomy. ARC-T Study Group. Astigmatism Reduction Clinical Trial.

BACKGROUND: We studied the safety and efficacy of arcuate transverse keratotomy performed for the primary correction of naturally occurring corneal astigmatism. METHODS: A multicenter, prospective evaluation of one-stage arcuate transverse keratotomy was conducted in 160 eyes with 1.00 to 6.00 diopters (D) of naturally occurring astigmatism. Vector analysis was used. After 1 month, those eyes that needed further refractive surgery received radial keratotomy for myopia and second-stage arcuate transverse keratotomy for residual astigmatism. RESULTS: Mean preoperative refractive cylinder was 2.80 D. At 1 month, the vector-corrected change was 2.30 D. Eighty-eight (61%) eyes had at least 1.00 D of residual refractive cylinder and 24 (17%) had at least 2.00 D. Eyes undergoing a second surgery averaged 1.60 D of vector-corrected effect, for a total effect of 2.90 D from both surgeries, indicating the astigmatic refractive effects were not additive. Eyes that had radial keratotomy alone as the second surgery demonstrated a similar change in refractive cylinder as eyes that had both radial and transverse keratotomies. Two eyes lost two lines of spectacle-corrected visual acuity, 29 eyes lost one line, 84 showed no change, and 26 eyes improved one line. CONCLUSION: Arcuate transverse keratotomy reduced refractive astigmatism. Both overcorrection and undercorrection were common. Complications were infrequent but occasionally caused significant irregular astigmatism. Arcuate transverse keratotomy appears to be a safe procedure with few complications.

Adolescent↗
PubMedDate not supplied

Risk factors for corneal graft failure.

BACKGROUND: Penetrating keratoplasty is one of the most common and successful ophthalmic procedures. However, controversy and uncertainty still call to question the significance of certain risk factors for graft failure. METHODS: A consecutive series of 1819 penetrating keratoplasties at a single center was studied to determine donor and recipient risk factors for graft failure. Mean follow up was 2.3 years (range, 1 to 96 months) with 139 (7.7%) eyes lost to follow up. RESULTS: Previous graft failure was the most significant risk factor for secondary failure (P = .0013). The risk of failure significantly decreased with increased postoperative time. Significant patient risk factors for secondary failures in initial grafts included race (P = .01), age (P = .004), iris color (P = .02), use of preoperative glaucoma medications (P = .0008), deep stromal vascularization (P = .002), and host horizontal diameter (P = 0.007). Significant risk factors for failures associated with immunologic allograft reactions in initial grafts included horizontal corneal diameter (P = .002), donor size (P = .05), differences between horizontal corneal diameter, and both donor size (P = .02) and recipient trephination size (P = .01). However, deep stromal vascularization was only marginally significant (P = .09). A history of preoperative glaucoma medication usage was not a significant risk factor. CONCLUSIONS: The relationship of the recipient's horizontal corneal diameter to immunologic graft rejection is a new risk factor that surgeons can directly control and thereby help avoid graft failure.

Adult↗
PubMedDate not supplied

Air lamellar keratoplasty.

Lamellar keratoplasties often result in decreased postoperative visual acuity from irregularities and opacities in the interface, sometimes have difficulty in matching the thickness of the resected recipient bed and the donor tissue, and may develop vascularization of the host-donor interface. I describe my experience with a new technique of injecting air into the corneal stroma to form a plane of dissection for deep lamellar keratectomy just anterior to Descemet's membrane. A full thickness donor button with the endothelium removed was used. Results are reported on ten eyes of ten patients. Follow-up ranged from 6 to 15 months (mean, 11 months). Three cases were converted to penetrating keratoplasty at the time of surgery and one five months after surgery. Of the remaining six, only one had a dissection completely to Descemet's membrane. All six recovered spectacle-corrected visual acuity of 20/40 or better. The technical limitations of this procedure are described.

Adult↗
PubMedDate not supplied

Long-term results of Molteno implants.

We retrospectively reviewed 76 Molteno implants in 72 eyes, with a minimum of 18 months' follow up. Double-plate implants were used initially in 64 of these eyes. After a mean follow up of 33.27 months, the mean intraocular pressure (IOP) was 14.0 mm Hg, as compared with 35.31 mm Hg preoperatively. With success defined as an IOP greater than 5 mm Hg but no greater than 21 mm Hg at the last visit, the success rate was 74%. If the four cases of chronic hypotony without loss of best-corrected vision are included, the success rate was 79%. The most frequent complications included corneal graft failure, filtration tube blockage, choroidal effusion, and hyphema/vitreous hemorrhage.

Adolescent↗