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Biomedical subjects

W L Alward

Publications and source records attributed to W L Alward.

At least 55 records · Page 3Linked to original sources
PubMed1995

Combined phacoemulsification, posterior chamber intraocular lens implantation, and trabeculectomy with mitomycin C.

PURPOSE: We evaluated the effectiveness of combined phacoemulsification, posterior chamber intraocular lens implantation, and trabeculectomy with mitomycin C in patients with coexisting cataract and glaucoma. METHODS: We conducted a retrospective review of the records of 21 consecutive patients who had combined phacoemulsification, posterior chamber intraocular lens implantation, and trabeculectomy with mitomycin C. Patients were selected for the combined procedure on the basis of the degree to which intraocular pressure was controlled, toleration of medical therapy, degree of glaucomatous optic nerve damage, and extent of visual impairment because of cataract. Nine (43%) of the 21 patients had previous incisional surgery and were at high risk of surgical failure. All patients had at least six months' follow-up. Sixteen (76%) of 21 patients had at least one year of follow-up. RESULTS: The mean preoperative intraocular pressure was 20.8 +/- 5.0 mm Hg (range, 13 to 35 mm Hg), which decreased to a mean postoperative intraocular pressure of 15.1 +/- 3.1 mm Hg (range, 9 to 21 mm Hg) as measured at last follow-up (P = .0002). The intraocular pressure was controlled between 6 and 21 mm Hg) in all patients at last follow-up. Seventeen (81%) of 21 patients had a best-corrected visual acuity of 20/40 or better at last follow-up. No patient had a decrease in visual acuity after surgery. Fifteen (71%) of 21 patients were using no antiglaucoma medications at last follow-up. Four of the remaining six patients were using one medication, and two were using two medications. A hyphema (less than 1.0 mm) was seen in seven (33%) of 21 patients and was the most common postoperative complication. No patient had a postoperative wound or bleb leak or a shallow anterior chamber. No patient developed symptomatic hypotony. CONCLUSIONS: The glaucoma triple procedure with adjunctive mitomycin C appears to be a safe and effective surgical technique for treating selected patients with coexisting cataract and glaucoma.

Adult↗
PubMed1995

Linkage of posterior polymorphous corneal dystrophy to 20q11.

Posterior polymorphous dystrophy (PPMD) is an autosomal dominant disorder of the cornea that is clinically recognized by the presence of vesicles on the endothelial surface of the cornea. The corneal endothelium is normally a single layer of cells that lose their mitotic potential after development is complete. In PPMD, the endothelium is often multi-layered and has several other characteristics of an epithelium including the presence of desmosomes, tonofilaments, and microvilli. These abnormal cells retain their ability to divide and extend onto the trabecular meshwork to cause glaucoma in up to 40% of cases. A large family with 21 members affected with PPMD was genotyped with short tandem repeat polymorphisms distributed across the autosomal genome. Linkage was established with markers on the long arm of chromosome 20. The highest observed LOD score was 5.54 (theta = 0) with marker D20S45. Analysis of recombination events in four affected individuals revealed that the disease gene lies within a 30cM interval between markers D20S98 and D20S108.

Chromosome Mapping↗
PubMed1995

Linkage of autosomal dominant iris hypoplasia to the region of the Rieger syndrome locus (4q25).

Iris hypoplasia is an autosomal dominant disorder which is frequently associated with glaucoma. This glaucoma is usually resistant to medical therapy and can lead to blindness. A large family of Scandinavian descent with a five generation history of iris hypoplasia was studied. Fifteen individuals were found to have iris hypoplasia, nine of whom had associated glaucoma. In an attempt to identify the chromosomal location of the disease-causing gene, this family was genotyped with short tandem repeat polymorphisms (STRPs) known to map to loci previously associated with glaucoma. The juvenile glaucoma locus at 1q25 and a congenital glaucoma locus on 6p were both statistically excluded. However, significant linkage was demonstrated at the Rieger syndrome locus at 4q25. The highest observed LOD score was 3.70 (theta = 0) and was obtained with marker D4S1616. Three recombination events were observed in affected individuals that together demonstrate that the disease-causing gene lies between markers ACT3E03 and D4S1611, an interval of approximately 7 cM. These results suggest that autosomal dominant iris hypoplasia and Rieger syndrome are allelic.

Chromosomes, Human, Pair 4↗
PubMed1994

Nocturnal arterial hypotension and its role in optic nerve head and ocular ischemic disorders.

We measured 24-hour ambulatory blood pressure monitoring and diurnal curve of the intraocular pressure in 166 white patients with anterior ischemic optic neuropathy, normal-tension glaucoma, primary open-angle glaucoma, and other optic nerve head disorders. Hourly average blood pressure data analyses showed a significant (P < .0001) decrease in mean systolic (26%) and diastolic (33%) blood pressure measurements at night. A significantly (P = .0028) lower nighttime mean diastolic blood pressure and a significantly (P = .0044) greater mean percentage decrease in diastolic blood pressure were noted in normal-tension glaucoma than in anterior ischemic optic neuropathy. Patients with arterial hypertension taking oral hypotensive therapy showed a significant association between progressive visual field deterioration and nocturnal hypotension, particularly in anterior ischemic optic neuropathy. Intraocular pressure showed no significant correlation with visual field deterioration in any of these conditions. Our findings suggest that nocturnal hypotension, in the presence of other vascular risk factors, may reduce the optic nerve head blood flow below a critical level, and thereby may play a role in the pathogenesis of anterior ischemic optic neuropathy and glaucomatous optic neuropathy; that is, nocturnal hypotension may be the final insult in a multifactorial situation. The same mechanisms may be true of a number of other ocular ischemic disorders. This finding opens a new dimension in the understanding and management of these visually disabling diseases.

Adult↗
PubMed1993

Clinical features and linkage analysis of a family with autosomal dominant juvenile glaucoma.

BACKGROUND: Juvenile glaucoma is an uncommon form of open-angle glaucoma that is usually recognized during childhood or early adulthood and which often has a strong family history. METHODS: The authors clinically characterized a large multigeneration family with autosomal-dominant, juvenile-onset, open-angle glaucoma. Linkage analysis with short tandem repeat polymorphisms was used to evaluate the Rieger's syndrome locus as the site of the disease-causing mutation. RESULTS: Forty members of a family with a five-generation history of open-angle glaucoma were examined. Clinical data were available from an additional five individuals, three of whom were decreased. Older family members provided limited information about the visual history of five other deceased individuals in the first three generations. Fifty-nine people were at 50% risk of harboring the disease-causing mutation; and of these, 30 were affected with glaucoma by examination or by family history. All affected patients had an affected parent. The average age at diagnosis was 18 years (range, 8-30 years). Affected family members tended to be myopic but lacked other ocular or systemic abnormalities. The intraocular pressures (IOPs) of affected individuals were commonly more than 50 mmHg when they were first examined. Gonioscopy showed the angles to be open, with no abnormal pigmentation, iris processes, or embryonic tissue. Topical medications were initially effective in controlling IOP, but surgery was usually required for long-term pressure control. The Rieger's syndrome locus on chromosome 4q25 was excluded as the site of the disease-causing mutation. CONCLUSION: Juvenile open-angle glaucoma can occur as an autosomal dominant trait with high penetrance. Genetic linkage analysis of the family reported here has the potential to identify the chromosomal location of a glaucoma-causing gene. This gene is genetically distinct from the chromosome 4 locus that was recently associated with Rieger's syndrome.

Adolescent↗
PubMed1993

Genetic linkage of familial open angle glaucoma to chromosome 1q21-q31.

Glaucoma is a significant cause of blindness world wide. There is evidence to suggest that at least a subset of the disease is determined genetically. We studied 37 members of a family affected with an autosomal dominant form of juvenile open angle glaucoma and 22 were found to be affected. Linkage analysis using short tandem repeat markers mapped the disease-causing gene to chromosome 1q21-q31. Eight markers were significantly linked (Zmax > 3.0) to the disease, with the highest lod score 6.5 (theta = 0), provided by D1S212. The atrial natriuretic peptide (ANP)/receptor system has been proposed to have a role in glaucoma and one of the ANP receptor genes maps to chromosome 1q.

Chromosome Mapping↗
PubMed1993

Experimental endoscopic goniotomy. A potential treatment for primary infantile glaucoma.

PURPOSE: The purpose of this study is to determine if an endoscope would improve visualization of the anterior chamber angle and facilitate goniotomy in a surgical cloudy corneal model of primary infantile glaucoma. METHODS: A 23-gauge needle coupled to a 0.8-mm diameter flexible endoscope entered the anterior chamber of porcine cadaver eyes through a corneal incision near the limbus. Internal structures were observed on a videoscreen and recorded as the needle approached and incised pectinate ligaments near Schwalbe's line. The eyes were then prepared for light microscopy and scanning electron microscopy. RESULTS: Internal structures were clearly visualized on the videoscreen during the goniotomy. The incision of pectinate ligaments was accompanied by the iris falling back and opening of the trabecular meshwork compared with the untreated portion of the angle. This was confirmed histopathologically. CONCLUSIONS: An endoscope coaxially coupled to a goniotomy needle tip allows visualization of the anterior chamber angle during goniotomy in the pig despite the presence of a cloudy cornea. The porcine anterior chamber angle is a useful animal model for studying the surgical treatment of primary infantile glaucoma.

Animals↗
PubMed1992

Effects of jogging exercise on patients with the pigmentary dispersion syndrome and pigmentary glaucoma.

BACKGROUND: Exercise-induced anterior chamber pigment dispersion with intraocular pressure (IOP) elevation has been reported in patients with the pigmentary dispersion syndrome. Marked pigment dispersion with or without elevation of IOP could predispose these patients to visual field loss. The authors designed this study to evaluate the effects of jogging exercise on anterior chamber pigment and IOP in a group of patients with the pigmentary dispersion syndrome or pigmentary glaucoma. METHODS: Fourteen subjects with the pigmentary dispersion syndrome, 10 subjects with pigmentary glaucoma, and 10 control subjects underwent a 45-minute protocol of jogging exercise. Anterior chamber pigment was graded and IOP was measured before and up to 3 hours after completion of the exercise protocol. RESULTS: Eyes of experimental subjects were significantly more likely to develop exercise-induced pigment dispersion than were eyes of control subjects. In experimental subjects, eyes treated with pilocarpine at the time of the study were significantly less likely to develop exercise-induced pigment dispersion than eyes not treated with pilocarpine. In two experimental subjects, pre-exercise treatment with pilocarpine appeared to inhibit exercise-induced pigment dispersion. CONCLUSIONS: The authors do not believe that all patients with the pigmentary dispersion syndrome or pigmentary glaucoma need to avoid exercise. However, for patients with these disorders who regularly engage in jogging or more strenuous or more jarring types of exercise, they suggest an evaluation before and after the type of exercise in question. If marked exercise-induced pigment dispersion occurs, pilocarpine therapy may be an alternative to avoidance of the exercise.

Anterior Chamber↗
PubMed1992

Linkage of Rieger syndrome to the region of the epidermal growth factor gene on chromosome 4.

Rieger syndrome is an autosomal dominant disorder of morphogenesis in which previous cytogenetic arrangements have suggested chromosome 4 as a candidate chromosome. Using a group of highly polymorphic short tandem repeat polymorphisms (STRP), including a new tetranucleotide repeat for epidermal growth factor (EGF), significant linkage of Rieger syndrome to 4q markers has been identified. Tight linkage to EGF supports its role as a candidate gene, although a recombinant in an unaffected individual has been identified. This study demonstrates the utility of using polymorphic STRP markers when only a limited number of small families are available for study.

Abnormalities, Multiple↗
PubMed1991

Long-term visual function in acute posterior multifocal placoid pigment epitheliopathy.

Acute posterior multifocal placoid pigment epithellopathy is a chorioretinal inflammatory disease occurring in young, healthy adults. The long-term visual prognosis and recurrence rate is uncertain. We reexamined 28 patients (53 affected eyes) with acute posterior multifocal placoid pigment epitheliopathy (mean follow-up, 8 years) to obtain details on the long-term functional visual outcome. The final visual acuities were 20/25 or better in 48 eyes (90.6%), 20/30 to 20/100 in four eyes (7.5%), and 20/200 in one eye (1.9%). Although the final visual acuity was good, 33 eyes (62.3%) were symptomatic with blurred vision, metamorphopsia, or scotomas. Thirty-six eyes (67.9%) had significant central visual field defects on follow-up examination. There were no recurrences after the initial month of symptoms. The chorioretinal scars did not enlarge with time. Acute posterior multifocal placoid pigment epitheliopathy has a good longterm prognosis for visual acuity, although most patients have residual symptoms and paracentral scotomas.

Acute Disease↗
PubMed1991

A multilens case.

Explore the source record for details and available documents.

Contact Lenses↗
PubMed1991

Effect of cataract on automated perimetry.

Humphrey visual fields (30-2 program) were performed on 24 otherwise healthy patients before and after cataract extraction to examine the effect of cataract on automated visual fields. All patients met reliability index criteria and recovered visual acuity of 20/25 or better. The effect of learning associated with repeated testing was controlled with visual fields of the fellow eye. Although a greater absolute threshold recovery occurred in the central region of the visual field after cataract extraction, the percent of threshold recovery did not vary across the visual field except for the most peripheral testing points, which demonstrated less recovery. Thus, cataracts depress an automated visual field fairly uniformly. Clinical grading of cataracts by a single experienced clinician was generally a poor predictor of visual field loss. Only the presence of posterior subcapsular plaque in the visual axis and the preoperative visual acuity correlated significantly with postoperative central threshold recovery. Pattern standard deviation remained unchanged after cataract removal, confirming it as a useful way of estimating visual loss from cataracts.

Aged↗