Biomedical subjects

Jonathan M Holmes

Publications and source records attributed to Jonathan M Holmes.

44 records · Page 3Linked to original sources

PubMed2003

Reliability of the electronic early treatment diabetic retinopathy study testing protocol in children 7 to <13 years old.

PURPOSE: To assess the test-retest reliability of the electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) visual acuity algorithm using the computerized Electronic Visual Acuity (EVA) tester in children 7 to <13 years old. DESIGN: Test-retest reliability study. METHODS: This multicenter study involved 245 subjects at four clinical sites. As the main outcome measure, visual acuity was measured twice using the E-ETDRS testing protocol on the EVA system, which uses a programmed handheld device to communicate with a personal computer and a 17-inch monitor at a 3-m test distance. RESULTS: Test-retest reliability was high (r =.94 for right eyes and 0.96 for left eyes) and for both right and left eyes, 89% of retest scores were within 0.1 logarithm of the minimal angle of resolution (logMAR) (five letters) of the initial test score and 99% of retests were within 0.2 logMAR (10 letters). Reliability was high across the age range of 7 to <13 years. Based on 95% confidence level estimates, a change in visual acuity of 0.2 logMAR (10 letters) from a previous acuity measure is unlikely to result from measurement variability. CONCLUSIONS: The E-ETDRS protocol using the EVA has high test-retest reliability in children 7 to <13 years of age. Potential advantages include better standardization across multiple sites, the ability to directly capture data electronically with an automatic acuity score calculation, the reduction of potential bias by limiting the tester's role, and the requirement of only a single testing distance for measurements from 20/800 to 20/12. This computerized testing method should be considered when visual acuity is used as an outcome measure in eye research involving children 7 to <13 years old.

Adolescent↗

PubMed2003

Telemedicine approach to screening for severe retinopathy of prematurity: a pilot study.

PURPOSE: To evaluate the use of remote reading of digital retinal photographs in the diagnosis of severe (referral-warranted) retinopathy of prematurity (ROP) during longitudinal screening for ROP. STUDY DESIGN: Prospective, longitudinal cohort study. SUBJECTS: Forty-four consecutive premature infants at risk for ROP. METHODS: All infants were examined longitudinally, over a series of examinations, by indirect ophthalmoscopy (gold standard) and digital photography using the RetCam-120 Digital Retinal Camera (Massie Research Laboratories Inc., Dublin, CA) equipped with an ROP lens. Images were stored and read remotely by a masked reader. Referral-warranted ROP was defined as ROP in zone 1, the presence of plus disease or the presence of any stage 3 ROP. We determined whether and when referral-warranted ROP was diagnosed for each eye, of each infant, on each examination, during the course of each of the infant's screening. RESULTS: Severe (referral-warranted) ROP was diagnosed in 23 eyes by indirect ophthalmoscopy during their series of examinations. Digital photography had a sensitivity of 100% and a specificity of 96% in detecting referral-warranted ROP. The positive predictive value of digital photography was 92%, and the negative predictive value was 100%. In 87% of eyes, referral-warranted ROP was diagnosed by digital photography before or at the same time as indirect ophthalmoscopy. CONCLUSIONS: Longitudinal remote reading of digital photographs using the RetCam-120 system has excellent specificity and sensitivity in detecting referral-warranted ROP. This pilot study has shown that remote reading of digital photographs has promise for telemedicine strategies in ROP screening.

Cohort Studies↗

PubMed2003

Birth prevalence of visually significant infantile cataract in a defined U.S. population.

PURPOSE: To determine the birth prevalence of visually significant infantile cataract, using population-based comprehensive medical record retrieval, in a defined US population. DESIGN: Retrospective, population-based, medical record retrieval. METHODS: We reviewed records of all pediatric patients (0-17 years) coded as cataract during a 20-year period (1978 to 1997) using the resources of the Rochester Epidemiology Project. "Infantile cataract" was defined as a cataract diagnosed within the first year of life. "Possible infantile cataract" was defined as a cataract, diagnosed after the first year in a child born in Olmsted County, where there was no evidence of an acquired traumatic, acquired systemic, or acquired ocular etiology. Visually insignificant cataracts were excluded. RESULTS: Ten incident cases of visually significant infantile cataract were identified during the 20-year study period, yielding a birth prevalence of 3.0 per 10,000 live births (95% CI: 1.5-5.6 per 10,000). Five additional cases of visually significant "possible infantile cataract" were identified, diagnosed between the ages of 2 and 8 years. Inclusion of these "possible infantile cataracts" would result in an estimate of overall birth prevalence for visually significant infantile cataract of 4.5 per 10,000 live births (95% CI: 2.5-7.5 per 10,000). CONCLUSIONS: Using population-based medical record retrieval methods, we estimate the birth prevalence of visually significant infantile cataract to be 3.0 to 4.5 per 10,000. Infantile cataracts are an important cause of visual impairment in children and these data are useful in planning clinical trials and allocating health care resources.

Cataract↗

PubMed2003

Congenital dacryocystocele associated with intranasal cysts: diagnosis and management.

OBJECTIVE: To improve the diagnostic and therapeutic database for congenital dacryocystoceles. STUDY DESIGN/METHODS: Retrospective case study of 10 patients with dacryocystoceles treated in an academic integrated tertiary care practice. Management and outcomes are compared to previous reports in the literature. RESULTS: Between the years 1990 and 2001, 10 patients were diagnosed with dacryocystoceles. Seven were females, and 3 were males. Age ranged from 1 to 75 days. Nine of 10 had a unilateral dacryocystocele, and 1 had bilateral dacryocystoceles. Epiphora was reported in 8 patients. Preoperatively, dacryocystitis, facial cellulitis, or both were present/developed in 2 patients. Symptoms of airway obstruction were present in 3 neonates. Surgery was performed in 9 of 10 patients and was a combined ophthalmology/otolaryngology surgery in 7 cases. Two patients were treated with probing only. Intranasal cysts were identified in all 7 patients who underwent a combined approach. Three of 7 patients had bilateral intranasal cysts. Follow-up ranged from 9 months to 10 years (mean, 5 years). Complete resolution was observed in 9 patients. One patient had postoperative nasolacrimal duct obstruction 2 months postoperatively, presenting with mucopurulent drainage and cellulitis. The existing literature often suggests conservative management as a treatment option. CONCLUSION: True dacryocystoceles are a relative rarity. The literature describes a variable natural course of these lesions with resultant controversy in their management. The current results demonstrate successful treatment in 6 of 7 patients with an early combined surgical approach and 2 of 2 patients treated by probing alone. The high failure rate with conservative management, reported in the literature, supports early surgical intervention.

Cysts↗

PubMed2002

Postoperative stereoacuity following realignment for chronic acquired strabismus in adults.

BACKGROUND: There is controversy regarding whether or not visually mature individuals can permanently lose stereoacuity and under what conditions stereoacuity can be regained. Some have proposed a critical duration of misalignment in adults beyond which recovery of fine stereoacuity is not possible, despite successful surgical alignment. METHODS: Twenty-one adult patients (median age 59 years) with large-angle acquired strabismus and who were successfully surgically aligned after 7 to 501 months of misalignment were studied. Subjects had no evidence of motor or sensory fusion since the onset of strabismus, on preoperative exam, or by history. Stereoacuity was measured using 1 or more of the Frisby, Preschool Randot and Titmus tests, at 8 weeks and at 12 months. Data from tests with monocular clues were not used. RESULTS: At total of 67% of patients with chronic acquired strabismus and no preoperative fusion regained measurable stereoacuity and 44% regained fine stereoacuity of at least 60 seconds of arc. Of 10 patients with no or subnormal stereoacuity 8 weeks postoperatively, 6 (60%) showed improvement at the 12-month visit. Misalignment for up to 4 years did not preclude the development of postoperative stereoacuity. CONCLUSIONS: Although a minority of adult strabismus patients may permanently lose stereoacuity despite successful alignment for acquired strabismus, the majority do show recovery. Such recovery of stereoacuity may take several months to occur. In our adult series, duration of misalignment did not predict failure to recover stereoacuity.

Adolescent↗

PubMed2002

Long-term outcomes after surgical management of chronic sixth nerve palsy.

BACKGROUND: In a multicenter prospective data collection study of chronic sixth cranial nerve palsy, we previously reported that the initial successful outcome rate was 39% after a single surgical intervention and 25% after surgery combined with botulinum toxin (Botox), using strict success criteria. We now report the longer term outcome of these patients. METHODS: A previously described cohort of 31 patients in 18 centers who underwent strabismus surgery for a sixth nerve palsy of greater that 6 months duration was studied prospectively. Twenty-three had strabismus surgery alone and 8 surgery with Botox. Fourteen (45%) were complete palsies and 17 (55%) were incomplete. Seven (23%) were bilateral and 24 (77%) were unilateral. Outcome was classified at time of last follow-up, which was 5 weeks to 24 months postoperatively. Success was defined as no diplopia in primary position at distance fixation. Partial success was defined as no more than 10 PD esotropia despite diplopia. RESULTS: Overall, 16 (52%) of the patients were classified as successes, 7 (23%) as partial successes, and 8 (25%) as failures. Three (43%) of the partial successes were using prism. Eight (35%) of the patients classified as successes or partial successes required 2 surgical procedures. Of all patients (10, 32%) who had a second surgery, only 2 (20%) remained failures. CONCLUSIONS: Despite our reported poor initial surgical success rate in chronic sixth nerve palsy, additional strabismus surgery, longer follow-up, and the use of prism or face turn for small residual deviations yields an overall surgical success rate of 75%. More than 1 surgical procedure and prism are often necessary in the management of chronic sixth nerve palsy.

Abducens Nerve Diseases↗

PubMed2002

Duration of acidosis and recovery determine preretinal neovascularization in the rat model of acidosis-induced retinopathy.

PURPOSE: Systemic acidosis is a risk factor for retinopathy of prematurity (ROP). The present study tested the hypotheses that: a) a short period of acidosis is sufficient to produce neovascularization and b) recovery from acidosis is not needed for the development of preretinal neovascularization. METHODS: Newborn Sprague-Dawley rats raised in 38 litters of 25 were randomly assigned within litters to 1, 3, or 6 days of acidosis, induced by twice daily gavage with NH4Cl (10 mM/kg) beginning on the second day of life. Recovery time ranged from 0 to 15 days. All animals were raised in room air. Animals were sacrificed and retinal vasculature was assessed for preretinal neovascularization and retinal vascular areas. RESULTS: Neovascularization occurred in up to 34% of rats exposed to 1 day of acidosis, 38% of rats exposed to 3 days of acidosis, and 55% of rats exposed to 6 days of acidosis. The incidence of neovascularization was maximal after 2 to 5 days of recovery regardless of the duration of NH4Cl exposure. However, recovery was not a requirement for the development of neovascularization. CONCLUSIONS: Periods of systemic acidosis as brief as 24 hours are associated with preretinal neovascularization in our newborn rat model of ROP using expanded litters. Systemic acidosis may damage the developing retinal vasculature and induce neovascularization, even without a period of recovery. A brief episode of systemic acidosis may be a risk factor for ROP in human neonates. Further attention should be directed to systemic acid-base balance in infants at risk for ROP.

Acidosis↗

PubMedDate not supplied

The effect of L-thyroxine supplementation in a neonatal rat model of ROP.

PURPOSE: The role of L-thyroxine in retinopathy of prematurity (ROP) is controversial. Recent animal studies suggest both high and low levels of serum thyroxine (exogenous supplementation and pharmacologic inhibition) are associated with preretinal neovascularization (NV) or retinal vascular retardation, a precursor of NV. To address this controversy, we studied L-thyroxine supplementation in an animal model of ROP. METHODS: Five hundred newborn Sprague-Dawley rats were raised in 20 expanded litters of 25, under conditions of fluctuating high and low oxygen and high carbon dioxide, to induce preretinal neovascularization. Rats received either 3 days of intraperitoneal T4, 7 days of T4 or saline control. Doses of T4 ranged from 0.005 microg/g to 0.5 microg/g. Retinae from left eyes were dissected, flat-mounted, and ADPase-stained. The presence and severity of NV, retinal vascular area, and retinal vascular density were scored in a masked manner. RESULTS: The incidence of NV was similar in rats receiving either 3 days of T4 or 7 days of T4 and saline controls (55% and 43% NV in 3-day experiments [0.05 microg g-1 day-1 and 0.5 microg g-1 day-1] compared with 51% in saline controls, p = 0.49; 52% and 38% in 7-day experiments [0.005 microg g-1 day-1 and 0.05 microg g-1 day-1], p = 0.22). Retinal vascular area and vessel density were also similar to saline controls. CONCLUSIONS: Systemic T4 supplementation does not increase, or decrease, the incidence or severity of preretinal neovascularization in an animal model of ROP, despite its positive effect on overall animal growth. Further work is needed to elucidate the potential role of premature infant hypothyroidism in the pathogenesis of ROP.

Animal Nutritional Physiological Phenomena↗