Biomedical subjects

Pradeep Sharma

Publications and source records attributed to Pradeep Sharma.

24 records · Page 2Linked to original sources

PubMed2003

Single-stage adjustable strabismus surgery for restrictive strabismus.

PURPOSE: To evaluate the feasibility and stability of ocular alignment of single-stage adjustable strabismus surgery (SSASS) in restrictive strabismus. METHODS: This was an observational case series comprising 12 patients with restrictive strabismus (mean age, 54.8 years) who were treated with SSASS using intravenous midazolam, fentanyl, and topical anesthesia. All were studied in a retrospective institutional manner. The refractive strabismus in 7 patients was caused by dysthyroid orbitopathy. Five patients had undergone previous ocular surgery, and 4 had undergone previous strabismus surgery. SSASS typically involved the vertical rectus muscles. Horizontal rectus muscles were adjusted when necessary. Silicon-treated polyester suture material (Ti-cron; United States Surgical, Norwalk, CT no longer available), 6-0, were used for inferior rectus recessions. Ocular alignment was set at ortho at the end of surgery and evaluated at 2 days, 6 weeks, and 3 months after surgery. The typical hang-back procedure was to lock the suture at the middle and edges of the tendon or muscle at the intended disinsertion point. The tendon was then disinserted and hung back from the original insertion with adjustments until the desired position (ortho) and single vision were attained. RESULTS: All patients remained comfortable throughout surgery and had no significant postoperative discomfort. All patients except 2 (16.6%) maintained satisfactory vertical alignment (<2 prism diopters). These 2 patients with dysthyroid orbitopathy had progressive overcorrection after inferior rectus recession. CONCLUSIONS: SSASS, using intravenous midazolam, fentanyl, and topical anesthesia, is a safe and precise alternative treatment for patients with restrictive strabismus including those with dysthyroid orbitopathy.

Adult↗

PubMed2003

Comparative evaluation of Teller and Cardiff acuity tests in normals and unilateral amblyopes in under-two-year-olds.

PURPOSE: To compare and evaluate Teller Acuity Cards (TAC) and Cardiff Acuity Cards (CAC) to assess vision in children below the age of two. METHODS: The study evaluated TAC and CAC to assess visual acuity in 90 normal children divided into three age groups, 0-6 months (group I), 6-12 months (group II) and 12-24 months (group III). 30 cases of unilateral amblyopiogenic conditions, 10 cases each of unilateral refractive error, unilateral esotropia, and unilateral cataract, were also examined. Trained optometrists carried out binocular testing followed by monocular testing, and recorded the test time in each case. RESULTS: The mean visual acuity (in Snellen units) and standard deviation (in octaves) in the three age groups of normal children, I, II, III respectively were 6/44 +/- 0.54, 6/21 +/- 0.37 and 6/21 +/- 0.41 (binocularly by TAC) and 6/46 +/- 0.80, 6/21 +/- 0.59 and 6/14.5 +/- 0.84 (binocularly by CAC). Although the time taken for testing with CAC was less, its coefficient of variance was greater for all age groups as compared to TAC. Diminution of visual acuity could be assessed correctly by both the tests in cases of strabismus and cataract, but not in some cases of refractive error. CONCLUSION: CAC is a useful and child-friendly test. It can be used clinically but may miss some cases of visually significant refractive errors. TAC is a more dependable test to assess amblyopiogenic conditions despite the use of gratings.

Amblyopia↗

PubMed2002

Analytical method for monitoring concentrations of cyclosporin and lovastatin in vitro in an everted rat intestinal sac absorption model.

Cyclosporin A (CSA) and lovastatin (LV) are lipophilic drugs, which show poor and erratic absorption when administered perorally. The permeability of these compounds can be increased transiently by altering the membrane characteristics of the absorptive epithelium by the use of sorption promoters (SPs). In the present work a simple validated HPLC method utilizing an isocratic mobile phase with short retention times for CSA and LV was developed in order to monitor their concentrations in Kreb's Ringer bicarbonate (KRB) solution in vitro in intestinal sac absorption model. The same method was utilized to determine the apparent permeability coefficients and absorption profiles of CSA and LV by a modified Wilson-Wiseman method. Drugs were analysed by a reversed-phase HPLC method using a Shim-pack C18 column. An isocratic mobile phase containing acetonitrile and water in the proportions 70:30 and 80:20 was used for the HPLC analysis of CSA and LV, respectively. The flow-rate was 2 ml/min and quantitative determinations were carried out at 215 nm at 70 degrees C for CSA. In the case of LV the flow-rate was 1 ml/min and detection was done at 238 nm at 25 degrees C. The method was found to be specific as none of the proposed SPs, components of KRB or intestinal sac artefacts interfered with the drug peaks. Recovery studies and intra- and inter-day variations were within statistical limits. The limits of detection were 250 and 10 ng/ml and the limits of quantitation were 400 and 30 ng/ml for CSA and LV, respectively. The calibration curve was found to be linear in concentration range of 0.5-6 microg/ml for CSA and 0.05-0.4 microg/ml for LV. The proposed method was found to be rapid and selective and hence can be applied for continuous monitoring of CSA and LV in vitro in intestinal sac absorption studies.

Animals↗

PubMed2002

Discordant pursuit asymmetry and esotropia in monozygous twins.

PURPOSE: To report the relationship between infantile esotropia and asymmetry of monocular pursuit tracking. DESIGN: Observational family case series. METHODS: A twin pair discordant for infantile esotropia was confirmed by DNA analysis to be monozygous at 99.95% probability. Digitally sampled electro-oculographic recordings of monocular horizontal pursuit eye movements were performed for the twins and their orthophoric father. RESULTS: Mean directional asymmetry for right and left eyes was 31% and 5% for the esotropic twin, 10% and 8% for the orthophoric twin, and 5% and 6% for the father. The asymmetry was statistically significant only for the deviating right eye of the esotropic twin (P = 0.0217). CONCLUSION: In this family, monocular pursuit asymmetry is probably not a heritable predisposition to infantile esotropia, but a consequence of early strabismus. Discordance of infantile esotropia and pursuit asymmetry in monozygous twins implicates environmental in addition to genetic causes.

DNA↗

PubMed2002

Levodopa-carbidopa with occlusion in older children with amblyopia.

PURPOSE: To study the role of levodopa-carbidopa in supplementing occlusion therapy in older children with strabismic or anisometropic amblyopia. METHODS: A clinical study was performed on 40 amblyopic children (19 strabismic and 21 anisometropic), 6 to 18 years old (mean age, 10.9 years). They received an average dose of 1.86 mg/kg/day (1.33-2.36 mg/kg/day) of levodopa and carbidopa (4:1 ratio) or a placebo in 3 divided doses over a 4-week period, combined with full-time occlusion. The occlusion was continued for the study duration of 3 months. Early Treatment Diabetic Retinopathy Study visual acuity charts and Cambridge low-contrast gratings for contrast sensitivity (CS) were used to assess visual functions. Tolerance and compliance with occlusion and capsule consumption were assessed. RESULTS: Visual acuity of the nonamblyopic eye did not deteriorate during the study in either group. CS decreased by 22 units in the levodopa group and increased in the placebo group by 53 units at the first month. The CS in the levodopa group recovered later by the third month of follow-up. Both the levodopa and the placebo groups showed significant improvement in visual function in the amblyopic eye (P <.001). Overall changes in logarithm of minimum angle of resolution values and CS in the amblyopic eyes were similar in both groups (P >.05). Strabismic and anisometropic amblyopes did not behave differently. Drug tolerance, occlusion compliance, and capsule ingestion compliance were similar between the groups, with no significant side effects. CONCLUSIONS: Clinically, levodopa supplementation does not offer any advantage over occlusion alone. Moreover, the risk of occlusion amblyopia could increase with the use of drugs like levodopa that might affect the plasticity of the visual cortex.

Adolescent↗

PubMedDate not supplied

Effect of posterior tenectomy of the superior oblique on objective and subjective torsion in cases of superior oblique overaction.

PURPOSE: To evaluate the effect of posterior tenectomy of the superior oblique on the correction of A-pattern, superior oblique overaction and the changes in torsion that occur in such cases. PATIENTS AND METHODS: This prospective study included 15 consecutive cases of bilateral superior oblique overaction with an A-pattern of more than 20 PD, a difference of deviation between 25 degrees up-gaze and 35 degrees downgaze, and superior oblique overaction of 2+ to 3+ on a scale of 0 to 4+. Deviation was measured in the primary position, 25 degrees upgaze, and 35 degrees downgaze using the prism bar cover test, and torsion was measured using a synoptophore, the double Maddox rod test, and fundus photographs. Measurements were obtained preoperatively and postoperatively at 1 week, 1 month, and 3 months. All case-patients underwent a standard temporal route posterior tenectomy of the superior oblique by a single surgeon. RESULTS: Mean age was 11.2 +/- 4.2 years with 14 cases of A-pattern exotropia. Mean superior oblique overaction was 2.60 +/- 0.50 in the right eye and 2.26 +/- 0.45 in the left eye, which decreased postoperatively to 2.20 +/- 0.56 and 1.80 +/- 0.41, respectively. The index of surgical effect was 0.84 in the right eye and 0.79 in the left eye. Postoperatively, mean correction of the A-pattern was 17.53 +/- 5.82 PD (index of surgical effect, 0.7). Subjective measurement of torsion was more consistent with the synoptophore compared with the double Maddox rod test. Objective measurement of torsion (fundus photography) was higher compared with subjective measurement. Postoperatively, there was insignificant change in the amount of torsion in upgaze and primary position. CONCLUSION: Posterior tenectomy of the superior oblique results in significant and controlled weakening of the superior oblique and collapse of the A-pattern with a clinically insignificant change in the amount of torsion.

Child↗