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Biomedical subjects

C G Summers

Publications and source records attributed to C G Summers.

60 records · Page 4Linked to original sources
PubMedDate not supplied

The effect of grating orientation on resolution acuity in patients with nystagmus.

The acuity card procedure is an effective method for the assessment of grating acuity in preverbal and nonverbal patients. However, the effect of nystagmus on this acuity assessment has not been well-described. We studied the effect of grating orientation on the measurement of resolution acuity in a group of nystagmus patients, a group of patients with albinism and nystagmus, and a normal control group. The resolution acuity was significantly (P < or = .01) better with horizontal grating orientation in both the nystagmus and the albino groups, but grating orientation did not affect resolution acuity in the control group. This study suggests that grating orientation must be taken into account when using the acuity card procedure in patients with nystagmus.

Adult↗
PubMedDate not supplied

Predicting visual acuity in children with colobomas involving the optic nerve.

BACKGROUND: This study evaluates the relationship to visual acuity of four ophthalmoscopic features of colobomas involving the optic nerve. The goal was to identify those features that could predict potential visual acuity of children with these colobomas. METHODS: Fundus photographs of 23 eyes with colobomas involving the optic nerve met the entry criteria and were evaluated by two masked observers. The following features were evaluated: coloboma size, optic nerve color, foveal development, and subfoveal retinal pigment epithelial changes. Simple linear regression was used to identify the feature that most closely correlated with visual acuity. Refractive status was assessed by cycloplegic refraction. RESULTS: The only component that correlated with the development of good visual acuity was the degree of foveal involvement by the optic nerve coloboma (P = .002, R = 0.8). Significant refractive error and anisometropia were common in patients with colobomas involving the optic nerve. CONCLUSION: Central visual acuity in children born with colobomas involving the optic nerve correlates with the development of normal foveal anatomy, regardless of the size of the coloboma, the color of the optic nerve, or the presence of subfoveal pigmentary changes. Because refractive error is common, these children should receive an accurate refraction and amblyopia treatment.

Child, Preschool↗
PubMedDate not supplied

Office probing for congenital nasolacrimal duct obstruction: a study of parental satisfaction.

PURPOSE: To determine parental satisfaction with nasolacrimal probings performed in the office without sedation for congenital nasolacrimal duct obstruction. METHODS: We reviewed the charts of 81 consecutive children under 4 years of age who underwent nasolacrimal probings in our office. Sixty-seven caretakers of these children were contacted by telephone to determine parental satisfaction, probing effectiveness, procedural complications, and future recommendations. A comparison between parental satisfaction and patient age, probing effectiveness, and unilateral versus bilateral probings was performed. RESULTS: Most caretakers (86%) were satisfied with the procedure and most (81%) would prefer the probing to be performed in the office rather than under general anesthesia (6% were unsure). Satisfaction rates were similar between the different age groups (P > .5 by Chi-square analysis), but were slightly lower in the unsuccessful probing and bilateral probing subgroups. Parents of children who underwent both an office procedure and a subsequent procedure under general anesthesia tended to prefer the office-based technique. CONCLUSION: The majority of caretakers of children who underwent unilateral or bilateral nasolacrimal probings in the office without sedation were satisfied with the procedure and, when given a choice, preferred it over probings performed under general anesthesia.

Ambulatory Surgical Procedures↗
PubMedDate not supplied

Myopia predicts better outcome in persistent hyperplastic primary vitreous.

PURPOSE: Persistent hyperplastic primary vitreous (PHPV) is a congenital disorder that presents with a spectrum of ocular anomalies, including cataracts, microphthalmia, and hyaloid vessel remnants. Severe visual loss due to secondary glaucoma and retinal detachment is common. This report evaluates the visual outcome of a variant of PHPV with myopia not associated with glaucoma. METHODS: The records of 23 consecutive patients with the diagnosis of PHPV (all unilateral) from October 1992 to August 1995 were reviewed. All but three patients had a cataract extraction procedure and all underwent amblyopia therapy. Eyes with a phakic myopic refractive error (Rx) or aphakic refractive correction < or = 8.5 diopters (D) in the immediate postoperative period were designated as myopic. RESULTS: Six patients were in the myopic group (Group 1) and 17 in were the nonmyopic group (Group 2). The mean age of diagnosis was 21.1 months in Group 1 versus 2.0 months in Group 2, with a comparable follow-up period of 36 months. The mean preoperative Rx of Group 1 was -7.78 D. The mean aphakic Rx of Group 2 was +18.29 D. Average axial length measurement determined by echography was 22.46 mm in Group 1 and 14.03 mm in Group 2. The mean corneal diameter was 11.3 mm in Group 1 vs 8.9 mm in Group 2. In Group 2, seven eyes developed retinal detachment and four developed glaucoma. These complications did not develop in Group 1 during the follow-up period. Overall functional visual acuity was better in Group 1, with a median visual acuity at final follow up of 20/160, as compared with light perception for Group 2. CONCLUSIONS: PHPV eyes with myopia were not detected as early as the typical PHPV eyes, primarily because of less media opacification and near-normal corneal diameters. These eyes showed a more favorable visual outcome as they were less likely to develop typical PHPV-related postoperative complications. Myopic PHPV eyes may require a different management approach.

Child, Preschool↗
PubMedDate not supplied

Anterior transposition of the superior oblique tendon in the treatment of oculomotor nerve palsy and its influence on postoperative hypertropia.

PURPOSE: To determine whether postoperative hypertropia after anterior transposition of the superior oblique tendon without trochleotomy could be avoided with a simplified surgical approach. METHODS: Eight patients with oculomotor nerve palsy (one patient was bilaterally affected) were retrospectively identified as having undergone anterior transposition of the superior oblique tendon without trochleotomy or vertical rectus muscle surgery between March 1992 and September 1998. The superior oblique tendon was cut at the medial border of the superior rectus muscle and placed 1-3.5 mm anterior to the medial insertion of the superior rectus muscle in each of these patients. Resection of the superior oblique tendon was not performed. The lateral rectus muscle was weakened, and no vertical rectus muscles were resected. RESULTS: Preoperative deviations with the uninvolved eye fixating in primary position ranged from 20-90 prism diopters (delta) of exotropia (mean: 49.3 delta) and from 0-20 delta of hypotropia (mean: 11.25 delta). Postoperative horizontal deviations in the primary gaze position ranged from 12 delta of exotropia to 20 delta of esotropia. Six cases were aligned within 10 delta of exotropia or esotropia. Postoperative vertical deviations in the primary gaze position ranged from 2 delta of hypertropia to 8 delta of hypotropia. Six cases were aligned within 2 delta of deviation. Significant postoperative restrictive hypertropia, or new postoperative paradoxical ocular movements, did not occur in any patient. Patients who underwent follow-up >4 months maintained stable eye alignment. CONCLUSION: Transposition of the superior oblique tendon without simultaneous resection or trochleotomy, or additional surgery to the vertical rectus muscle simplifies the surgical technique and eliminates subjective decision making regarding the amount of resection.

Adult↗