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F H Zaidi

Publications and source records attributed to F H Zaidi.

14 recordsLinked to original sources
PubMed2006

Subretinal membranes are associated with abnormal degrees of pupil "evasion": an index of clinical macular dysfunction.

AIM: To assess whether macular dysfunction caused by unilateral subretinal neovascular membranes (SRNs) is associated with pupil "evasion" (that is, increased initial rate of re-dilation following a brief light stimulus). METHODS: Comparative observational series. 20 eyes of 10 participants, all with unilateral SRNs and healthy fellow eyes. Dynamic infrared pupillography at seven stimulus intensities (duration 1100 ms, intensities over 2 log unit range). Pupil evasion ratio (PEVR; defined as the ratio of light response amplitude to amount of recovery at the mid-time point of re-dilation expressed as a percentage) was calculated for each stimulus intensity (mean of five recordings). RESULTS: Inter-eye PEVR is significantly reduced in eyes with SRN (that is, greater pupil evasion in SRN eyes: range p = 0.002 to p = 0.05 (paired t test)) and is most apparent at higher stimulus intensities. CONCLUSIONS: PEVR is a novel parameter that is analogous to the pupil escape ratio, but measured following a short rather than a sustained light stimulus. PEVR is significantly altered by macular disease. Clinically PEVR may be used to detect occult unilateral or asymmetric maculopathy in situations such as ocular media opacities like cataract, when pupil reactions are unaffected or augmented, while other tests of retinal function are diminished. PEVR represents altered neuronal firing in cones and macular ganglion cells.

Adult↗
PubMed2005

Variability in the content of Indian generic ciprofloxacin eye drops.

BACKGROUND/AIMS: Under-potent generic antibiotics sold in developing world countries may be contributing to positive selection of resistance organisms and to unpredictability in clinical outcome, leading to a loss of confidence among physicians locally. The objective of this study was to determine whether reports of unpredictable outcome for generic ciprofloxacin antibiotic eye drops in India could be the result of inadequate concentration of preparations sold by pharmacies. METHODS: 130 ciprofloxacin eye drop samples sold by pharmacies were collected from seven locations in north, central, and south India; 30 were randomly selected for testing. All samples were assayed using validated methods of reverse phase chromatography and fluorescence detection at a international antibiotic reference laboratory in the United Kingdom. Results were compared with advertised concentrations within the context of internationally accepted variability ranges. RESULTS: In total, six out of the 30 samples tested had ciprofloxacin concentrations lower than the standard advisory ranges of plus or minus 5% of stated content for 3 mg/ml pharmaceutical preparations. The ciprofloxacin content of these eye drops ranged from -36.4% to -16.1% of the stated content (median -21.73%). 24 out of 30 samples were found to be over the standard advisory ranges of plus or minus 5%, at a median of +19.42% (interquartile range (IQR) +14.28 to +25.13). Intra-batch variability of two selected samples was wide at -22.83% to +33.93% (n=11) and -17.07% to +31.20% (n=12). CONCLUSIONS: Approximately 20% of generic ciprofloxacin eye drops, purchased without prescription in India were under-potent. In a number of preparations the antibiotic content was sufficiently low as to have a potential impact on clinical outcome and possibly lead to the selection of resistant isolates in individual patients. More widespread studies are justified to identify the extent of under-potency of widely used generic antibiotic medications in developing countries.

Anti-Infective Agents↗
PubMed2004

Criteria for improving visual acuity in ischaemic branch retinal vein occlusion using argon laser.

PURPOSE: To re-assess the value of argon laser treatment for macular oedema in ischaemic branch retinal vein occlusion (I-BRVO). METHODS: Case series consisting of three patients with macular oedema following I-BRVO. Three patients were studied including two patients where ischaemia extended to include the foveal avascular zone (FAZ), with additional retinal neovascularisation in one of these. Heavy, overlapping areas of treatment were applied to the ischaemic retina up to 500 microns from the fovea. RESULTS: All cases in the series benefited from significantly improved visual acuity. In one case laser was given several years after the initial retinal vasculopathy. CONCLUSIONS: Argon laser treatment may improve visual acuity in I-BRVO even with severe ischaemia extending into the FAZ. Treatment intensity must be sufficient to destroy ischaemic retina. Visual benefit may last for several years, and treatment can be undertaken several years after I-BRVO. The benefit to visual acuity of argon laser treatment in I-BRVO needs to be re-assessed in a prospective study.

Female↗
PubMed2004

The Amsler chart is of doubtful value in retinal screening for early laser therapy of subretinal membranes. The West London Survey.

PURPOSE: Validating the current protocol of Amsler chart grid surveillance for the early detection of subretinal neovascular membrane(SRN) in age-related macular degeneration(AMD), and investigating its value in facilitating early laser therapy. METHODS: A retrospective pilot study. SETTING: Central London eye hospital with dedicated 24-h ophthalmic casualty serving West and West-central London. PARTICIPANTS: 100 consecutive AMD patients who attended casualty with vision loss fulfilling the following criteria: patients had received and been instructed in the use of Amsler charts according to the unit's dispensation protocol,fluorescein angiography which confirmed new SRN. Patients presented over 20 months. Outcome measures were detection of SRN by the Amsler chart, and laser treatment of SRN. RESULTS: The Amsler chart surveillance protocol had detected SRN in 29 of the 100 patients. The surveillance protocol detected less than 30% of the specific patients who subsequently underwent laser treatment. A statistically significant difference was seen on comparing the ages of patients in whom the screening protocol was successful versus those in whom it was unsuccessful (student's t-test,P<3.2 x 103). Younger patients were more likely to be detected using the Amsler chart. A one-tailed Z2 test approached, but did not achieve, statistical significance (Z2 = 1.057,P <0.3) suggesting that patients who have already lost vision to SRN in one eye might not be more likely to be detected using the surveillance protocol than patients in whom SRN was affecting their first eye. In all, 38% of surveillance responders went on to receive laser therapy, compared with 37% of surveillance nonresponders. CONCLUSIONS: The current Amsler chart surveillance protocol is suboptimal for detecting SRN in AMD, and a proportion of cases suitable for early laser therapy may be missing rapid detection. The results are especially important since recent advances in laser therapy for SRN require early detection for optimal effectiveness.

Age Factors↗
PubMed1998

Duplex scanning and effect of multisegmental arterial disease on its accuracy in lower limb arteries.

AIM: To assess the accuracy of duplex in assessment of peripheral arterial disease and determine the effect of multisegmental disease on the accuracy duplex as opposed to single lesion. PATIENTS AND METHODS: One hundred and seventy-seven lower limbs were examined in 90 patients who presented with lower limb arterial disease, (59 male, 31 female, median age 68 years--81 with intermittent claudication, eight rest pain, one ulceration). Patients were examined with duplex US, and arteriography (IA DSA). Two radiologists and two technologists were involved in this double-blind study. Patients were classified into five groups; groups with single stenotic lesions, single occlusions, multiple stenotic lesions or occlusions, and multiple mixed disease. Duplex accuracy was determined in each group. RESULTS: Duplex was able to differentiate between normal and disease arterial segment with a sensitivity of 92%, specificity 99%, PPV 91%, and NPV 100% and Kappa 0.87. Sixty-six limbs were found to have single lesions, and 68 multisegmental disease. Duplex showed accuracy with a sensitivity of 87%, and specificity of 99%, for single stenotic lesion and 95%, 96% respectively for multisegmental. For single occlusions duplex accuracy showed sensitivity 92% and specificity 100%, and for multisegmental occlusions, sensitivity 97%, and specificity 99%. For mixed multisegmental pathology (stenosis and occlusion), sensitivity 94% and specificity 97%. CONCLUSION: Duplex is an accurate tool in diagnosis of lower limb arterial disease and multisegmental pathology does not adversely effect this accuracy.

Aged↗