Biomedical subjects

S G Chedid

Publications and source records attributed to S G Chedid.

3 recordsLinked to original sources

PubMed1998

Visual Ability Score -- a new method to analyze ability in visually impaired children.

PURPOSE: We analyzed the correlation between the Preferential Looking (PL) acuities and the Visual Ability Scores (VAS) of 600 patients (many with severe retinopathy of prematurity) to determine their ability to perform various activities within the daily environment. METHODS: Visual acuity was measured by PL. Sixteen visual activities within the environment were analyzed. The VAS (range, 1-16) were calculated from the results of each activity and correlated with PL acuity. RESULTS: The PL acuities of the 600 patients ranged from 20/20 (1.0) to <20/3200 (0.006) [mean, 20/337(006)]. The VAS ranged from 1 to 16 points (mean, 10.65; SD, +/-4.80) and showed a high correlation with the PL acuities (r=0.917, p=0.0001). CONCLUSIONS: In addition to PL vision testing, analyzing the environmental visual behavior of young, severely visually impaired patients is important to accurately evaluate visual abilities. We found the VAS to be an important aid for low-vision specialists, especially for those with no access to a vision evaluation system such as PL.

Activities of Daily Living↗

PubMed1997

Five years' experience with the Grating disc. A simplified method of evaluating vision in young children.

The Grating Disc (GD) is a simplified visual test designed for children 18 months to 4 approximately 5 years. Two hundred pediatric patients (103 males, 97 females; aged 5 months to > 6 years) participated in this study to determined how the GD visual acuity (VA) correlates with the Preferential Looking (PL) VA. Forty-six percent of the patients had varying degrees of retinopathy of prematurity. The PL acuity was determined using the up-and-down staircase procedure. To measure GD acuity, six GDs with vertical gratings equivalent to acuities of 20/1920 to 20/60 were used. The examiner presented one GD simultaneously with the homogeneous disc from 57 cm. The VA was determined by the finest GD that the child could differentiate from the homogeneous disc. The overall correlation between the PL and the GD acuities was very high (R2 = 0.861). One hundred twenty-eight patients (64.0%) had an acuity agreement within 0.5 octave and 178 (89.0%) patients were within 1.0 octave. When the PL acuity was > or = 20/100, the GD and PL acuities showed good agreement. When the PL acuity was poorer, the GD acuity was poorer than the PL acuity. Although the GD acuity tended to be lower than the PL acuity in severely visually impaired patients, the GD acuity agreed with the PL in most visual assessments of young children. GD testing could be a useful alternative when sophisticated assessment systems such as the PL are unavailable.

Adolescent↗

PubMed1995

Correlating preferential looking visual acuity and visual behavior in severely visually handicapped children.

We developed a series of questions that reflects the functional abilities of severely visually handicapped children. The study population comprised 100 patients aged 30 to 60 months (mean 43.23), mostly afflicted with retinopathy of prematurity. Visual acuity was measured by preferential looking. Preferential looking acuities of the patients ranged from 20/25 (0.8) to 20/6400 (0.003) (mean 20/470 (0.04)). Ten activities were analyzed and correlated with preferential looking acuity. Among the selected visual activities, when children are not interested in television (p = 0.0001), toys (other than those that make sounds (p = 0.0001), and people (p = 0.001)), their preferential looking acuities were very low. For example, 73 out of 100 patients who were visually interested in television had preferential looking acuities (mean 20/245 (0.082)) that were significantly higher (p = 0.001) than 21 patients not interested in television (mean 20/2806 (0.007)). Patients with nystagmus (n = 79) had significantly lower preferential looking acuities (p = 0.0001) (mean 20/1114 (0.018)) than patients with no nystagmus (mean 20/57 (0.35)). When evaluating visual function in young, severely visually impaired patients, in addition to preferential looking testing, analyzing visual behavior within the environment is important to accurately evaluate their remaining visual abilities.

Child, Preschool↗