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Biomedical subjects

T O Wood

Publications and source records attributed to T O Wood.

At least 19 recordsLinked to original sources
PubMed1992

Growth of human corneal endothelium on altered Descemet's membrane.

To determine whether Descemet's membrane (DM), which is altered by disease, interferes with endothelial cell growth, healthy human corneal endothelial cells were seeded onto DM from normal corneas and diseased corneal buttons from patients with Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy (PBK). DM was first peeled off the corneal specimens and the endothelial cells removed by trypsinization. A suspension of first-passage corneal endothelial cells (2,000 cells/microliters; obtained from donor eye bank eyes and grown in Dulbecco's minimal essential medium with 10% fetal bovine serum and 1.5% chondroitin sulfate) were seeded on DM. Epidermal growth factor (10 ng/ml) and insulin (1 U/ml) were added to the medium after seeding cells on the DM. The cells attached and flattened within 1 hour and reached confluency in 1 week on normal DM. Cells grown on DM from corneas of patients with Fuchs' endothelial dystrophy also flattened and grew to confluency in 1 week. Cells grown on DM from corneas of patients with PBK did not grow to confluency. Further studies with bovine and rabbit corneal endothelial cells showed similar growth pattern to human cells. These data indicate that DM from corneas of patients with Fuchs' dystrophy does not interfere with the growth of corneal endothelial cells but that DM from corneas of patients with PBK does interfere with cell growth.

Animals↗
PubMed1991

Simultaneous penetrating keratoplasty, extracapsular cataract extraction, and intraocular lens implantation.

The postoperative results of 210 consecutive eyes in 177 patients who had simultaneous penetrating keratoplasty, extracapsular cataract extraction, and posterior chamber intraocular lens (IOL) implantation (triple procedure) were reviewed. All procedures were performed by one surgeon between January 1980 and December 1989. The most common diagnosis requiring a triple procedure was Fuchs' endothelial dystrophy. The remainder of the patients required the procedure for either corneal scarring, keratoconus, or Chandler's syndrome. Of the 210 grafts, 191 (91%) remained clear with a mean follow-up of 53 months (range 6 to 116 months). The mean preoperative keratometry (K) reading (n = 161) was 44.51/44.85 (SD 4.86/4.94), and the mean postoperative K reading (n = 111) was 44.29/43.50 (SD 3.83/3.63). The mean IOL power (n = 196) was + 20.87 diopters (D) (SD 2.86). The mean postoperative best visual acuity (n = 166) was 20/65 with a range from 20/20 to less than 20/400, although 61% had 20/50 acuity or better and 92% had 20/100 acuity or better. The mean spherical correction in 155 eyes was - 1.38 (SD 2.89), and the mean positive refractive cylinder was + 3.21 (SD 2.20). One hundred forty six of the 155 eyes with reported refractions (96%) had 6 D or less of refractive cylinder. Correlation of the recipient-donor disparity % and refractive cylinder was significant such that as disparity increased refractive cylinder increased (r = 0.197, P = .021). Correlation of the recipient-donor disparity % and keratometric cylinder indicated a similar trend but was not significant (r = 0.105, P = .310).

Adult↗
PubMed1991

Electron microscopic findings in corneal epithelial basement membrane degeneration.

In an attempt to correlate basement membrane changes with clinical symptoms we examined 29 specimens from 28 patients who had undergone corneal epithelial basement membranectomy for corneal epithelial basement membrane degeneration (CEBMD). Twenty-two of the 28 patients were women. Recurrent erosion was the most frequent symptom and occurred in 24 of the 29 eyes. The most common electron microscopic finding was reduplication of the basement membrane with loculated connective tissue. The electron microscopic finding that predicted clinical symptoms was absence of the basement membrane and hemidesmosomes, which occurred in 4 eyes with severe recurrent erosion.

Adult↗
PubMed1991

Suture adjustment for postkeratoplasty astigmatism.

Excessive corneal astigmatism following penetrating keratoplasty is a frequent problem. A technique that adjusts a single running 10-0 nylon suture after keratoplasty was used in this series of patients. The procedure requires a keratometer, slitlamp, topical anesthesia, and tying forceps. In 52 eyes, with an average of 10.0 diopters of keratometric astigmatism, we adjusted the suture to flatten the steep corneal axis. We were able to reduce astigmatism an average of 7.2 diopters and this remained stable three months post wound revision.

Adult↗
PubMed1991

Postkeratoplasty astigmatism control. Single continuous suture adjustment versus selective interrupted suture removal.

Two different suturing techniques performed during keratoplasty were retrospectively evaluated to compare postkeratoplasty astigmatism, number of suture manipulations, and time to optical stability. One group of patients (n = 31) received a combination of continuous 11.0 nylon suture and 12 or 16 interrupted 10.0 nylon sutures (CCIS), which were selectively removed post-operatively to reduce astigmatism. The second group of patients (n = 26) received a single continuous 10.0 nylon suture (SCS) that was adjusted postoperatively at the slit lamp to regulate corneal astigmatism. Compared with the CCIS technique, adjusting the single continuous suture resulted in less postoperative astigmatism (SCS, 1.5 +/- 1.1 diopters [D]; CCIS, 3.2 +/- 1.9 D), fewer suture manipulations per patient (SCS, 0.9 +/- 0.7; CCIS, 3.8 +/- 1.8), and earlier optical stability for visual rehabilitation (SCS, 2.6 +/- 1.5 months; CCIS, 9.6 +/- 4.7 months) (P less than 0.01). No continuous sutures were broken during adjustment. The adjustable single continuous suture may offer an improved method for early control of postkeratoplasty astigmatism.

Astigmatism↗
PubMed1990

An index for estimating probabilities of surgical success for cataract patients with retinal disease.

Patients with cataracts and coincident retinal disease are at increased risk for unsuccessful cataract surgery. We developed a method for estimating probabilities of surgical success for older cataract patients with retinal disease. Using data from a prospective study of cataract surgery outcomes, 36 patients with both cataracts and retinal disease were identified, 13 of whom attained surgical success with 20/40 or better vision 4 months after surgery. Age, presurgical Snellen letter acuity, location of retinal lesions, and presurgical visual function in everyday life (newspaper reading or television viewing) were all reliable correlates of surgical outcome. These data were analyzed using multiple logistic regression to develop a clinical index combining presurgical Snellen letter acuity, location of retinal lesions, and age to predict surgical success. The resulting index demonstrated 83% sensitivity and 85% specificity in sample data, correctly predicting 83% of patients (predictive value positive: 73%; predictive value negative: 90%).

Activities of Daily Living↗
PubMed1990

Cataract formation following corneal transplantation in eyes with Fuchs' endothelial dystrophy.

In a retrospective analysis, 78 eyes in 58 patients that underwent corneal transplantation for Fuchs' endothelial dystrophy were examined for the presence of cataracts. Follow-up ranged from 1 to 17 years, with an average of 6.62 years. Thirty-four (44.1%) of the eyes developed cataracts sufficient enough to require surgical removal. The mean time from transplant to cataract formation averaged 4.9 years. The average age at the time of transplant surgery in the eyes that did not develop cataracts was 55.6, and in those that developed cataracts, 60.3 (p = 0.049). Thirteen percent of the transplants lost transparency following cataract extraction. The incidence of postkeratoplasty cataract increased at age 50 and occurred in 75% of eyes grafted in patients 60 years of age or older.

Adult↗
PubMed1990

Salzmann's nodular degeneration.

Fifteen eyes in 12 patients with Salzmann's nodular corneal degeneration developed symptoms of recurrent erosion, decreased vision, or both. A history or evidence of ocular surface disease was present in 14 of 15 eyes. Removal of the nodule and accompanying pannus or corneal epithelial basement membrane degeneration, provided symptomatic improvement in all patients.

Adult↗
PubMed1990

Anterior stromal micropuncture electron microscopic changes in the rabbit cornea.

Anterior stromal micropuncture has become an effective treatment for recurrent erosion. The healing process in rabbit corneas was investigated. Following micropuncture of the corneal surface with a 27-gauge needle knife, electron microscopy was carried out at regular intervals from time 0 through 5 months. The corneal incisions began to fill with epithelium by day 1. Activated keratocytes were adjacent to the basement membrane defect by 7 days. The basement membrane appeared to be healed at 2 and 4 weeks. Epithelial projections into the stromal incisions with underlying mature basement membrane persisted at 5 months postsurgery. Basement membrane reproduction occurred much more rapidly following needle puncture than after microdiathermy. This was thought to occur because the corneal epithelial cell was immediately exposed to type I collagen, whereas following microdiathermy, new type I collagen must be secreted on the necrotic collagen before the corneal epithelium will secrete basement membrane.

Animals↗
PubMed1990

Aqueous humor protein and complement in pseudophakic eyes.

Intraocular lens (IOL) insertion is now the standard method of aphakic correction in this country. Previous studies have shown that an IOL can activate the alternative complement system of normal human serum in vitro, thereby generating peptides capable of stimulating inflammation that can result in visual morbidity in pseudophakic eyes. The objective of the present study was to determine if human aqueous humor (AH) levels of total protein, total C3, and C3a cleavage products (activated C3) are influenced by an IOL in pseudophakic eyes as compared with phakic and aphakic eyes. AH from five diagnostic categories was examined: cataract, posterior capsulotomy-IOL, Fuchs' endothelial dystrophy with corneal edema, aphakic bullous keratopathy, and pseudophakic bullous keratopathy. The results of this study do not support the hypothesis that IOLs affect AH protein and complement levels. Statistically, there was no significant difference in AH protein levels when pseudophakic eyes were compared with phakic and aphakic eyes. No significant difference in C3a levels was demonstrated between pseudophakic and phakic eyes, whereas aphakic eyes had significant higher levels than those with pseudophakia. There were significantly greater levels of protein, C3, and C3a in eyes with edematous corneas versus those with clear corneas. Although these studies are difficult to interpret, AH levels of these substances appear to be more related to dysfunctional corneal endothelium and corneal edema than to the presence of an IOL.

Aphakia↗
PubMed1989

Moderate Fuchs' endothelial dystrophy ATPase pump site density.

The Na+, K+-ATPase pump site density on corneal endothelial cells from Fuchs' endothelial dystrophy corneas has been shown to be drastically decreased in end-stage disease (McCartney et al, Invest Ophthalmol Vis Sci 28:1955, 1987) and significantly increased in the early stages (Geroski et al, Ophthalmology 92:759, 1985) as compared to normal endothelium. In order to provide values for corneas between these two extremes, eye bank corneas from donors with no evidence of corneal edema but with guttata across the extent of the cornea were processed for autoradiography as well as immunohistochemistry. Pump site density was increased compared to end-stage disease but was less than values reported for either functional tissue or early stage disease. Similarly, immunohistochemistry results showed the amount of Na+, K+-ATPase antibody localization to be increased in respect to end-stage disease, but reduced as compared to functional tissue. These results suggest that pump site density on endothelial cells affected with Fuchs' endothelial dystrophy follows a gradual decline towards end-stage disease values as opposed to a sudden sharp deterioration after an initial increase.

Aged↗
PubMed1988

A clinical index for predicting visual acuity after cataract surgery.

We developed a clinical index for predicting postoperative visual acuity of cataract patients and cross-validated it using data from 182 patients aged 70 years and older. The index consisted of four statistically combined indicators: age, preoperative visual acuity, frequency of reading, and comorbidity. Validation of the index included comparisons to two standard technical instruments for measurement of retinal visual acuity. For the clinical index, 72% of predictions were accurate within one Snellen line of postoperative visual acuity compared to 37% using a laser interferometer and 33% using a potential acuity meter. Testing of the clinical index's external validity using data from 111 patients in a different ophthalmology clinic disclosed 61% of predictions accurate within one Snellen line.

Aged↗
PubMed1988

Effect of carbachol on postoperative intraocular pressure.

Carbachol instilled in 125 eyes at the time of extracapsular cataract extraction and posterior chamber lens insertion had a statistically significant effect on lowering the postoperative intraocular pressure (IOP) at 24 hours (average IOP 14.0 mm Hg) and at 72 hours (average IOP 11.6 mm Hg) (P less than .001). The percentage of patients with an acute IOP elevation at 24 hours was also significantly reduced: carbachol 10% versus control 33% (P = .001). Carbachol's prolonged lowering of postoperative IOP may increase the safety of cataract surgery, particularly in patients with compromised optic nerves.

Carbachol↗
PubMed1988

Functional outcome one year following cataract surgery in elderly persons.

We conducted a prospective study of 164 patients aged 70 and over who had undergone cataract removal and intraocular lens implantation to determine variables which predicted change in physical function experienced by the patients one year after cataract surgery. Path analysis was used to estimate direct and indirect effects of ADL change. Direct effects were estimated for mental status (-.35), mental status change (.51), binocular visual disability (-.39), binocular visual disability change over one year (.51), and baseline ADL (.36), with 45% of variance explained. Age and baseline mental status had important indirect effects through mental status change, and presurgical visual disability had important indirect effects through both visual disability change and mental status change. In summary, change in level of function one year after cataract surgery was not explained solely by change in vision, but was conditional on baseline function and baseline mental status and mediated in part by change in mental status.

Activities of Daily Living↗
PubMed1988

Corneal decompensation following acute angle-closure glaucoma.

Ten eyes of nine patients with endothelial dystrophy requiring iridectomy for acute angle-closure glaucoma developed corneal edema sufficient to require penetrating keratoplasty. Because of the proximity of iris to cornea, simultaneous lens extraction was carried out to prevent malignant glaucoma. Penetrating keratoplasty using techniques presented here provided improved visual acuity and control of glaucoma in all cases.

Acute Disease↗
PubMed1988

Surgery for corneal epithelial basement membrane dystrophy.

Seventeen consecutive eyes with corneal epithelial basement membrane with symptoms of recurrent erosion and/or decreased vision were treated with corneal epithelial basement membranectomy. Younger patients tended to have recurrent erosion, whereas older patients had decreased vision. All patients' symptoms improved following surgery. Electron microscopy revealed reduplication of the corneal epithelial basal lamina.

Adult↗