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Biomedical subjects

David S Walton

Publications and source records attributed to David S Walton.

At least 19 recordsLinked to original sources
PubMed2006

Anterior axial lens subluxation, progressive myopia, and angle-closure glaucoma: recognition and treatment of atypical presentation of ectopia lentis.

PURPOSE: To describe the clinical features of an atypical presentation of ectopia lentis consisting of primary anterior axial lens subluxation in childhood, associated progressive myopia, and complicating angle-closure glaucoma; to facilitate early diagnosis of this triad; and to report the results of lensectomy for treatment. METHODS: A retrospective case review of eight patients. Clinical course, visual acuity, gonioscopy, axial length, refraction, fundus examination, associated systemic features, and results of treatment are provided. RESULTS: This subgroup of patients with ectopia lentis is at risk for progressive, synechial, angle-closure glaucoma. Identification of a clinical triad consisting of rapidly increasing myopia, normal axial length, and progressive axial subluxation leads to earlier diagnosis. Prophylactic lensectomy provides a safe and sight-saving treatment that arrests and, at times, reverses the progression of angle-closure glaucoma. CONCLUSIONS: Ectopia lentis with anterior axial subluxation and progressive myopia can be a sight-threatening condition when significant forward mobilization of the lens results in synechial angle-closure glaucoma. Recognition of this clinical entity can expedite diagnosis and prevent irreversible loss of vision secondary to glaucoma. Because the primary mechanism of angle closure is angle crowding, peripheral iridotomy does little to control the rise in intraocular pressure. Prophylactic lensectomy has proven to be the most reliable treatment in our experience.

Child↗
PubMed2005

Sex-specific effect of insulin-dependent diabetes 4 on regulation of diabetes pathogenesis in the nonobese diabetic mouse.

Many human autoimmune diseases are more frequent in females than males, and their clinical severity is affected by sex hormone levels. A strong female bias is also observed in the NOD mouse model of type I diabetes (T1D). In both NOD mice and humans, T1D displays complex polygenic inheritance and T cell-mediated autoimmune pathogenesis. The identities of many of the insulin-dependent diabetes (Idd) loci, their influence on specific stages of autoimmune pathogenesis, and sex-specific effects of Idd loci in the NOD model are not well understood. To address these questions, we analyzed cyclophosphamide-accelerated T1D (CY-T1D) that causes disease with high and similar frequencies in male and female NOD mice, but not in diabetes-resistant animals, including the nonobese diabetes-resistant (NOR) strain. In this study we show by genetic linkage analysis of (NOD x NOR) x NOD backcross mice that progression to severe islet inflammation after CY treatment was controlled by the Idd4 and Idd9 loci. Congenic strains on both the NOD and NOR backgrounds confirmed the roles of Idd4 and Idd9 in CY-T1D susceptibility and revealed the contribution of a third locus, Idd5. Importantly, we show that the three loci acted at distinct stages of islet inflammation and disease progression. Among these three loci, Idd4 alleles alone displayed striking sex-specific behavior in CY-accelerated disease. Additional studies will be required to address the question of whether a sex-specific effect of Idd4, observed in this study, is also present in the spontaneous model of the disease with striking female bias.

Alleles↗
PubMed2005

Glaucoma with the oculocerebrorenal syndrome of Lowe.

PURPOSE: To further describe the glaucoma with the oculocerebrorenal syndrome of Lowe (OCRL) including the responsible filtration angle abnormalities and response to treatment. METHODS: The scientific literature regarding the glaucoma associated with OCRL from 1952, when the first report of the syndrome appeared, to the present was reviewed. The medical records of 7 patients with OCRL were studied. The occurrence of glaucoma, corneal changes secondary to glaucoma, gonioscopic abnormalities, iris features, and response to glaucoma surgery were recorded. RESULTS: Signs of glaucoma are defining abnormalities leading to recognition of OCRL. The OCRL medical literature reports the frequency of glaucoma, secondary clinical signs of increased intraocular pressure (IOP), and results of glaucoma surgery, but little information related to the responsible filtration angle abnormalities. Glaucoma was present in 71% (5 of 7) of patients studied, and was recognized in infancy in 9 of their 10 eyes. Gonioscopy was performed in 6 OCRL patients and revealed the constant presence of open angles, primary filtration angle anomalies, and defects considered secondary to previous infantile lens extractions. The observed anomalies were anterior insertion of the iris, narrowing of the ciliary body band, and decreased visibility of the scleral spur. The angle defects felt to be acquired following lens surgery included a more anterior insertion of the iris on to the trabecular meshwork, pigment dusting of the angle tissues, and iris synechial abnormalities related to the surgery. Bilateral goniotomies were unsuccessful in 4 of 4 patients. The fundi of 6 of 7 patients showed normal optic disc development with variable abnormalities secondary to glaucoma, and normal retinal vessels. Minimal evidence of macular development was observed in a single patient from 1 month of age to his most recent examination at 14 months of age. CONCLUSION: A primary X-linked infantile glaucoma is a defining and frequent component of OCRL and is secondary to expression of a primary filtration angle anomaly. Goniotomy was unsuccessful in all (8) operated eyes. The adverse effects of cataract surgery on the filtration angle structures may influence the results of goniotomy surgery by superimposing a secondary aphakic glaucoma component that may explain the need for alternative glaucoma surgery.

Cataract↗
PubMed2004

Aphakic glaucoma after congenital cataract surgery.

OBJECTIVE: To describe the largest series of patients who developed aphakic glaucoma after lensectomy for congenital cataracts. METHODS: A retrospective review was performed of all patients seen by a pediatric glaucoma specialist between October 1, 1970, and November 30, 2002. Patients with intraocular pressures greater than 25 mm Hg after lensectomy were studied. Patients with either conditions independently associated with glaucoma or any signs of glaucoma before lensectomy were excluded. RESULTS: We studied 170 eyes of 117 patients. The mean +/- SD follow-up period was 8.6 +/- 7.6 years. The most common cataract types were complete (40.8%) and nuclear (22.5%). For the lensectomies, 103 eyes underwent modern vitrectomy techniques, and 10 underwent older techniques. Lensectomies were performed in 80.6% of eyes before age 1 year. Onset of glaucoma after lensectomy was by 1 year in 37.1% of eyes, by 6 years in 75.9%, and by 33 years in 100%. Of eyes that had gonioscopy, 93.9% had open angles. Glaucoma surgery was needed in 57.1% of eyes. The median final visual acuity was 20/400. CONCLUSIONS: Most cases of aphakic glaucoma are of the open-angle type. Various risk factors are suggested, and the prognosis is guarded. Lifelong follow-up is needed to screen for glaucoma.

Aphakia, Postcataract↗
PubMed2004

Goniosurgery for glaucoma complicating chronic childhood uveitis.

OBJECTIVES: To describe the safety and efficacy of goniotomy in medically uncontrolled glaucoma complicating chronic uveitis and the factors affecting its outcome. METHODS: All goniotomies performed by a single surgeon for refractory childhood uveitic glaucoma were retrospectively reviewed. Success was defined as final intraocular pressure (IOP) of no greater than 21 mm Hg without medications and qualified success as IOP of no greater than 21 mm Hg with medications. Unless otherwise indicated, data are expressed as mean +/- SD. RESULTS: Fifty-four goniotomies were performed in 40 eyes of 31 patients. Juvenile rheumatoid arthritis-associated uveitis was the diagnosis in 30 eyes (75%). Eleven eyes (28%) were aphakic. Mean follow-up was 98.9 months (range, 2-324 months). Mean age at surgery was 10.3 +/- 4.7 years (range, 4-22 years). Mean preoperative IOP was 36.7 +/- 6.4 mm Hg while receiving a mean of 2.9 +/- 1.1 medications. Overall surgical success was achieved in 29 eyes (72%), including success in 22 (55%) and qualified success in 7 (18%) while receiving a mean of 1.6 +/- 1.1 medications. Mean postoperative IOP in the success and qualified-success groups were 14.3 +/- 2.8 and 15.7 +/- 3.1 mm Hg, respectively. Kaplan-Meier survival probabilities (95% confidence interval) at 1, 5, and 10 years were 0.92 (0.82-1.00), 0.81 (0.65-0.97), and 0.71 (0.49-0.92), respectively. Phakic eyes, eyes with fewer peripheral anterior synechiae, patients younger than 10 years, and eyes with no prior surgery had significantly better outcomes. Hyphema, typically mild and transient, occurred in 43 procedures (80%). CONCLUSIONS: Goniosurgery is low risk and effective for refractory glaucoma complicating chronic childhood uveitis. It should be considered the surgical procedure of choice for this condition. Surgical outcome is adversely affected by increased age, peripheral anterior synechiae, prior surgeries, and aphakia.

Adolescent↗
PubMed2004

Congenital pupillary-iris-lens membrane with goniodysgenesis.

BACKGROUND: A unilateral congenital pupil-iris-lens membrane with goniodysgenesis syndrome, not benign tunica vasculosa lentis, was first described by Cibis et al. One of three cases developed angle closure. Robb described catastrophic vision loss from angle closure in one of his seven cases. METHODS: We did a retrospective review of previously unreported cases of pupil-iris-lens membrane with goniodysgenesis seen in our practices. RESULTS: We report the clinical spectrum of a further nine cases, three of which needed surgery for angle closure, two of which needed surgery for clearing the visual axis. CONCLUSION: Congenital pupil-iris-lens membrane with goniodysgenesis is a unilateral membrane clearly differentiated from benign persistent tunica vasculosa lentis tissue. The membrane represents ectopic iris on the lens with abnormal iris stroma and chamber angle from aberrant induction, migration, or regression of neural crest cells. The membrane can be progressive. Catastrophic vision loss from angle closure can occur and may be controlled with surgery. Surgery may be needed to open the visual axis even when glaucoma is not present and may prevent angle closure.

Anterior Eye Segment↗
PubMed2004

Management of childhood glaucoma.

PURPOSE OF REVIEW: Management of childhood glaucomas is a challenging responsibility. This review will highlight new information to assist with preparation for the care of patients with these disorders. RECENT FINDINGS: During the past year, work was reported revealing new causes of childhood glaucoma and incredible new insight into the responsible genetic defects. This report also reviews continued efforts to determine the indications and outcomes of goniosurgery, trabeculectomy procedures, and tube shunts for children. SUMMARY: Continued progress in understanding the genetics of childhood glaucoma and the selection of effective surgical procedures highlight progress reported in the last year and should assist with decision making for children with childhood glaucoma.

Child↗
PubMed2004

Goniosurgery for glaucoma secondary to chronic anterior uveitis: prognostic factors and surgical technique.

PURPOSE: To describe the preoperative prognostic factors that correlate with the surgical success of goniosurgery for glaucoma complicating chronic anterior uveitis and to describe the surgical technique. METHODS: The medical records of 31 patients with 31 eyes with glaucoma secondary to chronic anterior uveitis for which 38 goniotomy procedures were performed were reviewed. Uveitis etiology, gender, age of onset of iritis, duration of iritis before recognition of glaucoma, duration of iritis and duration of glaucoma until initial goniosurgery, preoperative gonioscopic findings, lens status, surgical outcome, age at initial goniosurgery, duration of postoperative observation, lens status, preoperative and postoperative intraocular pressures, topical steroid, and glaucoma medication use were reviewed. Complete success was defined by an intraocular pressure (IOP) < or = 21 mm Hg, and qualified success as IOP < or = 21 mm Hg with use of glaucoma medications. The surgical technique used to perform the goniosurgery was reviewed. RESULTS: Overall surgical success was achieved in 22 (71%) of 31 eyes. The mean age at surgery was 10.2 +/- 4.2 years (range, 4-21 years). All but 8 patients were female. Mean follow-up interval was 10.3 +/- 6.4 years (range, 1.5-22 years). Significant correlation was found between outcome and age at initial surgery, lens status, duration of glaucoma before goniosurgery, duration of iritis before glaucoma surgery, and hours of peripheral anterior synechia (PAS). The mean number of clock hours of preoperative (PAS) was 0.5 hours in eyes with success versus 2.5 hours in eyes with failure. Age of onset of iritis, duration of iritis before recognition of glaucoma, trabecular meshwork pigmentation (TM), TM opacification, and circumferential ciliary body band narrowing did not correlate with surgical outcome. CONCLUSION: Goniosurgery is an effective treatment of glaucoma secondary to chronic anterior uveitis. The outcome of surgery was unfavorably influenced by older age, longer duration of glaucoma, and evidence of more advanced preoperative filtration angle abnormalities secondary to uveitis. Goniosurgery for this secondary glaucoma can be successfully performed utilizing the standard goniotomy technique.

Adolescent↗
PubMedDate not supplied

Glaucoma in retinoblastoma.

The association between retinoblastoma and secondary glaucoma is well known. The most common cause of secondary glaucoma in retinoblastoma is iris neovascularization (NVI) followed by pupillary block and tumor seeding of the anterior chamber. Although glaucoma is a secondary clinical issue in retinoblastoma (RB) management and care, awareness of its presence, revealed by a thorough ocular exam of the anterior segment, can guide the clinician in assessing the overall condition of the affected eye.

Diagnosis, Differential↗
PubMedDate not supplied

Primary megalocornea: clinical features for differentiation from infantile glaucoma.

PURPOSE: To describe the ocular findings in megalocornea to assist in its differentiation from infantile glaucoma in the evaluation of children with abnormally enlarged corneas. METHODS: The clinical findings of 4 boys found to have megalocornea following referral for evaluation of large corneas and suspected glaucoma were reviewed. RESULTS: Three of the 4 patients had photophobia. Clear and enlarged corneas were observed associated with deep anterior chambers, posterior bowing of the irides, and normal intraocular pressures (IOPs) in all eyes. Transillumination of the irides was found in 6 of 8 eyes and pigment dispersion was seen in 4 of 8 eyes. Pigment dispersion appeared to be acquired over time, and the youngest patient in this series who had pigment dispersion detected on slit-lamp examination was 15 years; the youngest patient with the condition detected on gonioscopy was 8 years. No breaks in Descemet's membrane were present. Family history obtained from 3 of the 4 patients revealed evidence of sex-linked recessive inheritance. These findings are distinct from the clinical features of infantile glaucoma characterized by elevated IOP, breaks in Descemet's membrane, corneal edema, a generally flat iris profile, less pronounced enlargement of the anterior segment, the absence of iris transillumination and pigment dispersion, and autosomal recessive inheritance. Three patients had corneal size asymmetry, a finding that has not been previously reported. CONCLUSION: Hereditary megalocornea has defining clinical findings that help to identify and differentiate it from other causes of enlarged corneas. Asymmetry in corneal size does not preclude its diagnosis.

Child↗
PubMedDate not supplied

Ahmed valve surgery for refractory pediatric glaucoma: a report of 52 eyes.

PURPOSE: To describe the results of Ahmed valve surgery for refractory pediatric glaucoma. PATIENTS AND METHODS: We performed a retrospective review of patients younger than 18 years of age who had Ahmed valve surgery from November 1994 to January 2003. Success was defined as a reduction of the intraocular pressure (IOP) to 22 mm Hg or lower with or without medications at the last two follow-up visits, no additional glaucoma surgery, and no visually significant complications. RESULTS: There were 52 eyes of 41 patients. The two most common diagnoses were congenital glaucoma (38.5%) and aphakic glaucoma (36.5%). The mean number of glaucoma surgeries before Ahmed valve implantation was 1.7 +/- 1.7. The mean age at the time of implantation was 4.9 +/- 6.5 years. The mean IOP decreased from 38.1 +/- 6.4 mm Hg to 20.7 +/- 8.2 mm Hg at last follow-up. The final visual acuity was improved or within one Snellen line in 81.5% of the eyes. Cumulative probabilities of success were 85.1%, 63.2%, 51.7%, and 41.8% at 1, 2, 3, and 4 years, respectively. The mean postoperative follow-up period or time to failure for all patients was 2.2 +/- 1.8 years (range, 3 months to 7.5 years). CONCLUSIONS: The Ahmed valve was found to be useful in the management of refractory pediatric glaucoma. Although our success rates were similar to those observed in adults, the rates of certain post-operative complications were different.

Adolescent↗
PubMedDate not supplied

Primary congenital glaucoma: 2004 update.

BACKGROUND: Primary congenital glaucoma is the most frequent childhood glaucoma and an important cause of blindness. We describe the current understanding regarding this disease, the evaluation of children with it, and its treatment. PATIENTS AND METHODS: We accessed information derived from a review of 287 patients with primary congenital glaucoma and current published data related to primary congenital glaucoma. RESULTS: The nomenclature for childhood glaucoma has been inconsistent, but is clarified for children with primary congenital glaucoma. The epidemiology of primary congenital glaucoma notes its variable incidence worldwide. Familial occurrence supports autosomal recessive transmission; chromosomal loci have been identified, and the CYP1B1 gene has been identified and clinically correlated. The histopathology of eyes with primary congenital glaucoma confirms the presence of a variable trabecular meshwork anomaly and the absence of an imperforate membrane. Children with primary congenital glaucoma are diagnosed after recognition of corneal signs and symptoms of glaucoma. CONCLUSIONS: The examinations of patients with primary congenital glaucoma must be thorough to distinguish this glaucoma from other types of childhood glaucoma, to prepare for surgery, and to follow progress with treatment. Medical treatment must be tailored to the pediatric patient. Goniosurgery is the definitive procedure of choice for most children with primary congenital glaucoma, but other procedures are also used successfully after goniosurgery fails or is determined to be inappropriate. Future success will be determined by physicians who sustain continued progress for children with glaucoma.

Child↗