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Biomedical subjects

H Sherafat

Publications and source records attributed to H Sherafat.

5 recordsLinked to original sources

Effect of a patient training video on visual field test reliability.

AIMS: To evaluate the effect of a visual field test educational video on the reliability of the first automated visual field test of new patients. METHODS: A prospective, randomised, controlled trial of an educational video on visual field test reliability of patients referred to the hospital eye service for suspected glaucoma was undertaken. Patients were randomised to either watch an educational video or a control group with no video. The video group was shown a 4.5 minute audiovisual presentation to familiarize them with the various aspects of visual field examination with particular emphasis on sources of unreliability. Reliability was determined using standard criteria of fixation loss rate less than 20%, false positive responses less than 33%, and false negative responses less than 33%. RESULTS: 244 patients were recruited; 112 in the video group and 132 in the control group with no significant between group difference in age, sex, and density of field defects. A significant improvement in reliability (p=0.015) was observed in the group exposed to the video with 85 (75.9%) patients having reliable results compared to 81 (61.4%) in the control group. The difference was not significant for the right (first tested) eye with 93 (83.0%) of the visual fields reliable in the video group compared to 106 (80.0%) in the control group (p = 0.583), but was significant for the left (second tested) eye with 97 (86.6 %) of the video group reliable versus 97 (73.5%) of the control group (p = 0.011). CONCLUSIONS: The use of a brief, audiovisual patient information guide on taking the visual field test produced an improvement in patient reliability for individuals tested for the first time. In this trial the use of the video had most of its impact by reducing the number of unreliable fields from the second tested eye.

Aged↗

Plasma homocysteine, methylene tetrahydrofolate reductase C677T and factor II G20210A polymorphisms, factor VIII, and VWF in central retinal vein occlusion.

AIMS: To determine whether plasma homocysteine, methylene tetrahydrofolate reductase (MTHFR) C677T and factor II G20210A polymorphisms, factor VIII, and vWF are risk factors for central retinal vein occlusion (CRVO). METHOD: Prospective comparison of 63 consecutive patients with central retinal vein occlusion and 63 age matched controls. Plasma homocysteine and vWF were estimated by ELISA, the MTFHR and factor II G20210A polymorphisms determined by polymerase chain reaction with restriction enzyme product digestion and factor VIII by one stage automated clotting assay. RESULTS: Plasma homocysteine (patients: median 12.4 micromol/l, controls: median 11.6 micromol OR = 1.05, p=0.20), factor VIII (patients: median = 115 U/dl, controls: median = 113 U/dl), and vWF (patients: median = 115 U/dl, controls: median = 108 U/dl) were not statistically higher in patients than in controls. Five CRVO patients and seven controls were homozygous for the MTHFR C677T mutation. One control was heterozygous for the factor II G20210A mutation. CONCLUSION: This study has not identified new risk factors for CRVO.

Blood Coagulation↗

Anomalies of binocular function in patients with longstanding asymmetric keratoconus.

AIMS: To study binocular function in patients with longstanding asymmetric keratoconus. METHODS: In 20 adult patients with longstanding asymmetric keratoconus managed with a scleral contact lens a full clinical and orthoptic assessment was performed with and without the scleral contact lens in the poorer eye. RESULTS: All 20 patients had a corrected acuity of at least 6/9 in their better eye. With the scleral lens in situ the acuity of the poorer eye ranged from 6/6 to 6/60 and without the lens from 6/18 to hand movements. Patients were aged from 18 to 68 years and had worn a scleral contact lens for between 3 and 106 months. Without the contact lens in their poorer eye all patients had a small exotropia and all showed suppression, with the exception of one patient who had a right hypertropia with diplopia. With the scleral lens in situ 12 patients had an exophoria or esophoria, six a microexotropia, and two a manifest exotropia with suppression. CONCLUSIONS: Binocular function breaks down in some adult patients with longstanding asymmetric keratoconus. This is probably caused by longstanding unilateral visual deprivation. There are similarities to the breakdown of binocular function seen in some patients with a longstanding dense unilateral adult onset cataract who can develop intractable diplopia following cataract surgery.

Adolescent↗