Papers by David Schanzlin
Alternate and Classical Pathway Components of Complement in the Normal Cornea
Archives of Ophthalmology, Feb 1, 1980
Activation of complement by either the classical or alternate pathway may be involved in corneal ... more Activation of complement by either the classical or alternate pathway may be involved in corneal inflammation. This study was undertaken to determine whether the normal human cornea contains components for both classical and alternate pathway activation of complement. Direct immunofluorescence of corneas from human donors using fluorescein-labeled antiserums was used to demonstrate C1q, C3, C4, and C5. The C1q component (the recognition unit of the classical pathway and largest complement component) was found in the periphery of the cornea. Normal donor corneas were also eluted in phosphate-buffered saline at 4 degrees C for one to four days. Ouchterlony plates, in which the corneal eluate was reacted against antiserums to complement components, disclosed the presence of C1q, C3, C4, C5, properdin, and properdin factor B. Plasminogen was also found. Radial immunodiffusion was used to obtain estimates of the concentrations of C3, C4, and C5 in the cornea.
Evaluation and Comparison of Sources of Variability in the Measurement of Corneal Thickness with Ultrasonic and Optical Pachymeters
Ophthalmic surgery, lasers & imaging retina, Sep 1, 1983
Two studies were carried out to determine and compare the effects of several sources of variation... more Two studies were carried out to determine and compare the effects of several sources of variation on the measurement of corneal thickness using the standard optical pachymeter and three ultrasonic pachymeters. Sources of variation included: intra- and inter-session variation, inter-observer variation, left/right eye variation, and variations due to alternate settings of ultrasonic sound frequencies. It was found that the optical pachymeter had a) two to three times as much intra-session variation as that of the ultrasound pachymeters, b) significant inter-observer variation (P = 0.015), and c) significant differences between left and right eye thickness determinations (P less than 0.005). On the other hand, ultrasonic pachymeters demonstrated a) high reproducibility, b) no inter-observer variation, and c) no left/right eye variation. These results have implications for the use of pachymetry in measuring corneal thickness for radial keratotomy and other refractive surgery.
<title>Device for viewing the insertion of foldable IOL into sectioned eyes from the posterior pole</title>
Proceedings of SPIE, Jun 24, 1993
The study of insertion and deployment of foldable IOLs in cadaver eyes is enhanced by viewing the... more The study of insertion and deployment of foldable IOLs in cadaver eyes is enhanced by viewing the process from the posterior pole position. A video system was constructed to view IOL placement in sectioned eyes from the posterior position. All tissue used in this study were prepared using the VISUALEYESTM Surgical Practice System (Visitec Co., Sarasota, FL). This system allows for the precise placement and resection of the proximal third of the posterior segment of the globe. The remaining two-thirds of the globe is then placed onto the eye holder, which allows the tissue to be viewed from the posterior position. After the tissue has been prepared and attached to the fixation plate, the entire assembly is attached to the video system. A variety of intraocular procedures can then be performed utilizing this system. Both anterior and posterior views can be video taped for later analysis. Parameters such as IOL diameter, haptic length, positioning of the IOL within the eye and unfolding characteristics can be assessed using this system. This paper discusses the development of this device and presents examples of its use in the study of foldable IOL deployment.
Histopathology of Corneal Neovascularization
Archives of Ophthalmology, Mar 1, 1983
With the use of a previously described model of corneal neovascularization induced by thermal cau... more With the use of a previously described model of corneal neovascularization induced by thermal cautery, we examined the effects of inhibitors on both the incidence of corneal neovascularization and the degree of inflammatory cell response. Three known inhibitors of corneal neovascularization, 1% prednisolone acetate, indomethacin, and 0.3% flurbiprofen, were studied and the results were compared with those in saline-treated controls. As expected, corneal neovascularization, preceded by conjunctival and corneal polymorphonuclear leukocyte (PMNL) infiltration, occurred in all control animals. Corneal neovascularization did not occur in any of the inhibitor-treated eyes. Histopathologically, both conjunctival and corneal PMNL counts in the treated eyes were markedly reduced compared with controls. These findings are consistent with the hypothesis that inflammatory cells, particularly PMNLs, are closely associated with the initiation of corneal neovascularization.
Immunoglobulin Deposition in the Cornea After Application of Autologous Serum
Archives of Ophthalmology, Oct 1, 1988
A 47-year-old man with a history of multiple corneal allografts for recurrent herpes simplex kera... more A 47-year-old man with a history of multiple corneal allografts for recurrent herpes simplex keratitis developed a subtotal nonhealing corneal epithelial defect. The patient was treated with hourly drops of autologous serum. A ringlike infiltrate was subsequently observed, followed by reepithelialization of the graft. The patient later suffered allograft rejection of the cornea and recurrence of the epithelial defect, and a repeated penetrating keratoplasty was performed. Examination of the excised button demonstrated a total epithelial defect, changes compatible with allograft rejection, and, in addition, eosinophilic granular deposits within the superficial corneal stroma that corresponded to the &quot;immune ring&quot; observed clinically. Immunoperoxidase staining was positive for IgG, IgM, IgA, and kappa and lambda light chains. These pathologic changes lend credence to the hypothesis that the precorneal tear film may be a source of immunoglobulin that becomes deposited within the stroma.
Long-term storage of frozen lenticules for cryorefractive surgery
Journal of Cataract and Refractive Surgery, Nov 1, 1990
We studied freezing rates, cryoprotectants, and storage times on keratocyte viability, using rabb... more We studied freezing rates, cryoprotectants, and storage times on keratocyte viability, using rabbit corneal buttons incubated in either KM-26, CPTES, K-Sol, or TC 199 for 30 minutes at 4 degrees C. Using a controlled freezing rate (2 degrees/min to -40 degrees C), viabilities were 69 +/- 7% for KM-26, 113 +/- 21% for CPTES, 0.1 +/- 0.08% for K-Sol, and 0 +/- 0% for TC 199. The KM-26 and CPTES were further studied in corneas stored one to 30 days at -80 or -196 degrees C; CPTES had a better cryoprotective efficacy over one, three, and seven days of -80 degrees storage, and at liquid nitrogen storage temperature (-196 degrees) over one, 14, and 30 days storage. The findings demonstrate the superiority of CPTES. It provides better viability than KM-26 under similar conditions, and may enable long-term frozen storage of lenticules for later use in cryorefractive surgeries, with minimal loss of keratocyte viability.
Multicenter FDA Clinical Trial of Treatment of Presbyopia Using Scleral Implants: Preliminary Findings
The Annual ASCRS and ASOA Symposium and Congress, Apr 26, 2014
Descemets Stripping Endothelial Keratoplasty (dsek) As An Internal Sealant For Corneal Laceration Or Perforation
Investigative Ophthalmology & Visual Science, 2011
Identification of Microorganisms Utilizing the Two-Photon Ophthalmoscope
American Journal of Ophthalmology, 1993
Diabetes, Aug 1, 1979
We measured circulating hemoglobin A, (HbA,) and fasting plasma C-peptide concentrations in 100 d... more We measured circulating hemoglobin A, (HbA,) and fasting plasma C-peptide concentrations in 100 diabetic patients. Pancreatic insulin reserve showed a negative correlation with HbA, concentrations in nonobese, insulin-treated patients but not in obese patients, whether they were treated with insulin, oral agent, or diet alone. Patients with fasting C-peptide concentrations above 0.1 pmol/ml had significantly better metabolic control than did those with lower values. Anti-insulin antibodies were measured in 37 patients. There was no correlation between metabolic control and the affinity constants or binding capacities of these antibodies. DIABETES 28:749-753, August 1979. emoglobin A lc (HbA lc ) is the major, glycosylated hemoglobin present in red blood cells of healthy adults and diabetic patients. It is the product of a chemical reaction between glucose and the N-terminal valine of the beta chain of hemoglobin A 0 . 1>2 The concentrations of HbA lc , as well as those of the three minor hemoglobins are elevated in diabetic patients, 3 -4 The concentration of HbA, (HbA, a + HbA lb + HbA lc = HbA,) is mainly dependent on the prevailing plasma glucose level, and it correlates well with many of the methods available for assessing metabolic control in diabetic patients. 5 " 8 It was proposed, therefore, that the level of HbA, may serve as a quantitative indicator of diabetic control. In addition, HbA, measurements may help to evaluate the contribution of various factors known to affect diabetic control. In the following study we were interested in the influence of two such factors-namely, pancreatic insulin-secretory reserve and circulating anti-insulin antibodies-on diabetic control. Measurement of plasma C-peptide has proved to be a useful method for determining pancreatic insulin secretion From the
Two-Photon Ophthalmoscope Aids in Diagnosis of Infectious Keratitis
Refractive Index Shaping Of Intraocular Lenses Using The 2 Phase Wrapping Algorithm
Rapid Identification of Microorganisms Using the Two-Photon Ophthalmoscope
Descemets Stripping Endothelial Keratoplasty (dsek) As An Internal Sealant For Corneal Laceration Or Perforation
Reproducibility study of Placido-based corneal topography systems
Proceedings of SPIE, May 22, 1995
We have developed a computer software program that analyzes the reproducibility of corneal topogr... more We have developed a computer software program that analyzes the reproducibility of corneal topography systems. Using a Macintosh computer with Microsoft QuickBasic programming we created a program that records and analyzes the corneal power of 72,000 points per ...
Testing Visual Acuity Using Innovative Red-Green Test On The IPad And Other Mobile Devices
Comparison of contrast sensitivity in different soft contact lenses and spectacles
PubMed, 1999
Purpose: To compare the visual performance of soft contact lenses and spectacles. Methods: Twenty... more Purpose: To compare the visual performance of soft contact lenses and spectacles. Methods: Twenty eyes of ten patients were examined. Each patient was fit with Acuvue, Cibasoft, and Biomedics contact lenses in random order. LogMar visual acuity and contrast sensitivity using the VectorVision CSV-1000 were measured. Results: There was no significant difference in visual acuity between any contact lenses (P=.15). Contrast sensitivity at 12 cycles/degree was significantly lower for the Cibasoft lens compared to spectacles (P=.04). There was no significant difference between spectacles and contact lenses for remaining spatial frequencies (P=.07-.35). Conclusions: Visual acuity appears to be an insensitive method for evaluating soft contact lenses. The lathe-cut manufacturing process may be responsible for reduced visual function compared to cast-molded lenses. Further study in this area is needed.
The Change Of Bursting Strength In Sclera Tunnel Incision After Application Of An Adherent Ocular Bandage In Human Globes
Investigative Ophthalmology & Visual Science, Apr 22, 2011
American Journal of Ophthalmology, Dec 1, 1979
The controversy concerning the rela tionship between control of hyperglyeemia and the development... more The controversy concerning the rela tionship between control of hyperglyeemia and the development of long-term diabetic complications has been the sub ject of several reports. 1 ^3 This controversy continues partly because of the lack of adequate tests for the assessment of meta bolic control in diabetic patients. The measurement of hemoglobin Ai is a relatively reliable indicator of the timeaveraged blood glucose level during the preceding three to four weeks. This test presently provides the most reproducible long-term measure of glucose control in the diabetic patient. To learn if there is an association be tween metabolic control, as assessed by hemoglobin A x measurements, and the severity of diabetic retinopathy, we stud ied these factors in a consecutive series of 102 diabetic patients. We studied a consecutive series of 102 diabetic patients observed here between Jan. 1 and March 15, 1978. The following information was recorded for each pa tient: age, sex, race, height, weight, age at onset and dviration of diabetes, and type From the Departments of Ophthalmology (Drs.
Uploads
Papers by David Schanzlin