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Biomedical subjects

M Barsoum-Homsy

Publications and source records attributed to M Barsoum-Homsy.

22 records · Page 2Linked to original sources
PubMed1981

Medial rectus insertion site in congenital esotropia.

Because of the clinical observation that in patients with congenital esotropia the medial rectus is inserted closer to the limbus than we have classically been taught, the distance between the medial rectus insertion site and the limbus was measured at the time of corrective surgery in 26 infants under 1 year of age with congenital esotropia. The distance in the 52 eyes was found to vary between 3.0 and 5.5 mm (mean 4.5 mm; standard deviation 0.57 mm). Of the 25 patients available for follow-up assessment 8 required another operation because of a residual esodeviation greater than 10 prism diopters, yet in some of the 8 a maximum recession of the muscle (6 mm from the insertion site) had been done. It is proposed that the maximum recession be increased to 11.5 mm from the limbus. This might reduce the risk of undercorrection, especially in patients with an esodeviation above 70 prism diopters. Further studies need to be done to evaluate the normal insertion sites of the extraocular muscles in the different pediatric age groups.

Adult↗
PubMedDate not supplied

On- and off-responses in the photopic electroretinogram in complete-type congenital stationary night blindness.

We examined the on- and off-responses of the photopic electroretinogram in patients with complete congenital stationary night blindness. Standard flash electroretinograms as well as those produced in a ganzfeld modified for long-duration light stimuli (500 msec) permitted the separation of on- and off-responses in four patients and four normal subjects. The amplitude and latency of the elctroretinogram on-response (a- and b-waves) and off-response (d-wave) in addition to the oscillatory potentials of the off-response in normal subjects and patients were compared. The abnormal on-response was demonstrated in all the patients, and the off-response with its oscillatory potentials were preserved. We showed that the second portion of the off-response (of inner retinal origin) is normal. If congenital stationary night blindness is a defect of depolarizing bipolar cells, these results preclude input of the depolarizing bipolar cells and support the hyperpolarizing bipolar cells as the cellular origin of the off-response electroretinogram.

Adolescent↗