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Biomedical subjects

H Tabandeh

Publications and source records attributed to H Tabandeh.

52 records · Page 3Linked to original sources
PubMed1995

Phenylephrine and pilocarpine in the treatment of post-operative irido-corneal adhesion.

Following cataract surgery, entrapment of the iris within the surgical wound is often managed by intensive use of miotics. As the radial fibres stretch, only a small amount of fraction is exerted upon the entrapped iris. Application of a combination of phenylephrine and pilocarpine drops causes simultaneous contraction of the pupil sphincter and the radial muscle fibres. This study investigated the relative magnitude of forces induced in the iris periphery by pilocarpine and phenylephrine and the effectiveness of adding g. phenylephrine 10% to g. pilocarpine 4% drops in the treatment of postoperative irido-corneal adhesions. The investigation was divided into two parts. First, the forces induced in the iris periphery upon exposure to pilocarpine and phenylephrine were measured in 6 cadaver irises. The mean force was 27.5 +/- 5.7 x 10(-3) N for pilocarpine and 23.3 +/- 4.0 x 10(-3) N for phenylephrine. The combination of the two drugs produced a force of 54.2 +/- 6.6 x 10(-3) N (p < 0.05). In the second part of the study intensive pilocarpine 4% drops were administered to 17 patients who had iris-wound entrapment on the first post-operative day. Patients with persistent adhesion were commenced on intensive g. phenylephrine 10% and assessed after 90 minutes. Of the 17 patients, 6 responded to pilocarpine drops alone; in a further 7 the irido-corneal adhesion was released only by the addition of phenylephrine drops, and in 4 patients drops were ineffective in relieving the adhesion. This study indicates that addition of phenylephrine 10% to pilocarpine 4% drops enhances the effectiveness of pharmacological treatment of post-operative irido-corneal adhesion.

Cataract Extraction↗
PubMed1995

Auditing ophthalmology audits.

Medical audit is now a well-established part of the routine of ophthalmology departments. Accomplishing a complete audit is a complex task and its effectiveness depends on how it is performed. In order to evaluate the procedure in our department a retrospective analysis of 18 audits was carried out with particular reference to the level, objectives, beneficial effects, and effects on current practice. Our practice was critically analysed using these factors. One audit fulfilled the criteria for a full audit. Eleven (60%) were partial or potential and six (30%) were an attempt in planning an audit. The majority omitted plans for implementing change or targets for future assessment. Seven had educational benefit. There was little effect on patient care, cost-effectiveness or communication. Medical audit can be clinically effective, educational and stimulating. Failure to complete all stages affects the outcome. This study identifies the difficulties involved in performing complete audits and suggests improving the procedure by auditing audits on a regular basis.

Education, Medical↗
PubMed1994

Ophthalmologic features of thallium poisoning.

Thallium intoxication is characterized by the development of painful peripheral neuropathy, alopecia, mental disorders, and in severe cases, respiratory failure and death. Toxic optic neuropathy is also a feature. Ophthalmologic features of thallium poisoning include optic neuropathy, blepharoptosis, lens opacities, and ophthalmoplegia. A 44-year-old man with criminal sublethal thallium poisoning was examined one month after he was seen in the neurology department with classic systemic features. He was found to have diminished contrast sensitivity, a tritan defect in color vision, and a relative cecocentral scotoma before he developed optic atrophy.

Adult↗
PubMed1994

Lens hardness in mature cataracts.

A cataract is said to be mature when all the cortical fibres become opaque. Depending on the pathophysiological processes that cause the cortical fibre opacification this phenomenon may be associated with a varying degree of nuclear sclerosis. A relationship between lens hardness and degree of nuclear sclerosis in non-mature cataracts has been demonstrated previously. This study aimed to investigate the relationship between the hardness of mature cataracts and the transmitted nuclear colour, age and rate of progression of the cataract. Thirty-eight patients with mature cataracts were assessed prior to extracapsular cataract surgery. The nuclear colour that was transmitted through the opaque cortex was graded using reference photographs. Age and duration of visual symptoms were recorded and lens hardness was measured by a specially designed lens guillotine. Multivariate analysis of data indicates a relationship between hardness of a mature cataract and the transmitted nuclear colour and age (adjusted R2 = 0.59). There is also a tendency for hardening of the lens as the duration of visual symptoms increases. By considering these clinical markers, the cataract surgeon can estimate the hardness of the lens and therefore its suitability for phacoemulsification.

Age Factors↗
PubMed1994

Learning phacoemulsification: the surgeon-in-training.

With the increasing trend towards phacoemulsification a perceived increased complication rate during the learning curve gives rise to a dilemma as to the best stage at which a surgeon-in-training can safely learn the technique. We prospectively analysed the complications and visual outcome of the first 160 phacoemulsification procedures performed by three surgeons-in-training. The main outcome measures included posterior capsule tear, vitreous and nuclear loss, surgical re-intervention rate and visual outcome. Posterior capsule tear occurred in 7 eyes (4.4%) and vitreous loss in 6 (3.8%). No nucleus was lost in the vitreous. Surgical re-intervention was required in 1 eye. Best corrected visual acuity was 6/12 or better in 88% of eyes. These results compare favourably with reports of surgeons-in-training learning extracapsular surgery and also with recently reported phacoemulsification series. This study indicates that with careful case selection and supervision phacoemulsification can be a safe procedure.

Aged↗
PubMed1994

Water content, lens hardness and cataract appearance.

Hardening of a cataractous lens is associated with the clinical appearance of brunescence and advancing age. Alterations in the nature and concentration of proteins, lens fibre compaction and other biochemical changes may all be contributing factors towards increased hardness. As the nucleus confers most of the rigidity to the lens and water content decreases towards the centre of the nucleus, the hardness might be thought to be related to total water content. To study the relationship between water content, hardness and the clinical appearance of cataract, 135 lenses were obtained from eyes undergoing extracapsular cataract surgery. The cataracts were assessed and classified pre-operatively. Lens hardness was determined by a specially designed guillotine and water content was measured by weighing the lens before and after desiccation. A regression analysis was carried out to look at the variation of lens water content with hardness, degree of nuclear sclerosis, extent of cortical and posterior subcapsular cataract, vacuolation and age. Multivariate analysis of data demonstrated a relationship between lens hardness and lens water content, degree of nuclear sclerosis and age (R2 = 0.59). An association could not be detected between lens water content and age, degree of nuclear sclerosis, extent of cortical and posterior subcapsular cataract and vacuoles. This study suggests that hardening of the lens is reflected by a respective decrease in water content. Increased hardness is associated with coloration and advancing age.

Adult↗
PubMed1993

Conjunctival involvement in malignancy-associated acanthosis nigricans.

Acanthosis nigricans classically presents with pigmented skin lesions over the neck, groin and axillae. It may involve the mucosal surfaces, particularly the oral mucosa. Conjunctival involvement is very rare, especially in the variety associated with malignancy. We report a case of acanthosis nigricans associated with squamous cell carcinoma of the bronchus where bilateral papillary conjunctivitis, progressing to hypertrophic papillary conjunctival and lid margin lesions, was the presenting feature. Topical treatment with corticosteroid and artificial tear drops resulted in the partial improvement of the ocular symptoms.

Acanthosis Nigricans↗
PubMed1993

The relationship between clinical classification of cataract and lens hardness.

'Hardness' of the cataractous lens is one of the major factors influencing the suitability of a patient for phacoemulsification. Surgeons should be able to estimate hardness when choosing patients for this method of cataract extraction. The aims of the study were to investigate the relationship between the clinical appearance of cataracts and their hardness. Ninety-one lenses were studied from patients undergoing endocapsular cataract extraction. Lenses were assessed using a classification based on the Lens Opacities Classification System II and hardness was assessed using an automated lens guillotine. The degree of nuclear sclerosis and the age of the patient were found to influence lens hardness. Regression analysis showed that 56% of the variation in hardness could be explained in terms of age and the degree of nuclear sclerosis. The presence of posterior subcapsular and cortical cataract did not influence hardness. These findings confirm our clinical suspicions and enable surgeons to make a more objective analysis of hardness prior to phacoemulsification.

Adult↗
PubMed1993

Dellen causing disappearance of Vogt's limbal girdle (II): A compressive phenomenon?

The cornea remains clear and avascular partly as a result of the compactness of the stromal lamellae. Loosening of these lamellae promotes loss of corneal transparency and peripheral vascularisation. Conversely, increased compactness of corneal tissue may possibly result in resorption of certain peripheral opacities. We report a case in which increased corneal compactness, produced by dellen formation, resulted in the disappearance of a type II Vogt's limbal girdle.

Aged↗
PubMed1993

Learning phaco in a teaching environment.

We prospectively analysed the complications and visual outcome of the first 160 phacoemulsification procedures performed by three surgeons in training under supervision. The main complications were posterior capsular tear (4,35%), vitreous loss (3,3%), nuclear loss (none) and surgical reintervention (one). Postoperative visual acuity was 0,7 or better in 94% of eyes without pre-existing pathology. Only one eye did not have a posterior chamber lens implanted.

Cataract Extraction↗
PubMedDate not supplied

Retinal fibrovascular proliferation associated with Nocardia subretinal abscess.

PURPOSE: To report the development of extensive fibrovascular proliferation in association with Nocardia subretinal abscess. METHOD: Case report. RESULTS: Extensive retinal neovascularization with tractional retinal detachment developed soon after ocular involvement in a 61-year-old patient with systemic nocardiosis. Fundus fluorescein angiography showed extensive area of capillary nonperfusion and severe leakage from the neovascular complex. The Nocardia subretinal abscess responded to systemic antibiotics, and the retinal neovascularization and tractional retinal detachment stabilized after 3 months. CONCLUSIONS: Retinal ischemia and severe retinal neovascularization may complicate intraocular nocardiosis. The authors propose secondary retinal vasculitis as a contributing factor towards the development of retinal ischemia in this setting.

Abscess↗
PubMedDate not supplied

Effect of flurbiprofen on acetylcholine-induced pupillary contraction.

Preoperative treatment with topical nonsteroidal anti-inflammatory agents such as flurbiprofen (Ocufen) is used to maintain pupil dilation during cataract surgery. Flurbiprofen maintains pupil dilatation by inhibiting release of prostaglandins and other modulators of surgical miosis. Some reports suggest that these agents may reduce the miotic effect of intra-operative acetylcholine (Miochol). It is hard to explain this effect unless there is a pharmacological interaction between the two drugs. This study aimed to investigate the possibility of a direct interface by flurbiprofen with the action of acetylcholine on the pupil sphincter. Iris tissue of seven cadaver eyes were isolated and maintained in an organ bath containing Kreb's solution. Pupil contraction force induced by acetylcholine was measured in the presence and absence of flurbiprofen. Acetylcholine produced a mean pupillary contraction force of 52.4 x 10(-3) N. When it was added to the organ bath in the presence of flurbiprofen the mean contraction force was 50.5 x 10(-3) N (paired t-test P = 0.68). This study does not find any evidence to suggest that flurbiprofen reduces the pupil sphincter contraction that is induced by acetylcholine. It is likely that the apparent reduction in miosis is due to factors other than the mechanism of action of acetylcholine on the sphincter pupillae.

Acetylcholine↗
PubMedDate not supplied

Visual function during acute hypoglycaemia.

Hypoglycaemia symptoms are of particular interest in view of the importance of hypoglycaemia unawareness. Visual symptoms arising during acute hypoglycaemia may be the result of metabolic disturbances in the visual pathways within the central nervous system or impairment of the refractive apparatus of the eye and binocular function. This study investigated the effect of hypoglycaemia upon visual acuity, binocular interaction and contrast sensitivity. Various aspects of visual function were examined in ten normal subjects before, during and after acute insulin-induced hypoglycaemia. A simultaneous study of hypoglycaemic symptoms enabled us to relate the objective findings to the symptoms as reported by the subjects. Snellen visual acuity, fusion and stereopsis were not affected by hypoglycaemia. Five subjects noted visual disturbance. Eight developed significant impairment of contrast sensitivity, which closely matched the lowered blood glucose concentration. These observations suggest that hypoglycaemic visual symptoms are due to neuroglycopenia of central visual pathways rather than changes within the refractive apparatus or abnormality of binocular function. Although these symptoms are not a constant feature of the hypoglycaemic state, subtle impairment of visual function occurs in most cases. Contrast sensitivity testing can be useful for assessment of fine changes in visual function.

Accommodation, Ocular↗
PubMedDate not supplied

Systemic conditions in the Emergency Eye Clinic.

PURPOSE: A systemic disease may be diagnosed for the first time in patients who present to the eye department with ophthalmological manifestations. This study documents the pattern of systemic disorders which were encountered in an emergency eye clinic for the first time. SUBJECTS AND METHOD: Over a period of six months details of all patients who had a previously unknown systemic condition diagnosed in the Emergency Eye Clinic were recorded. Patients were seen in this clinic upon referral from other practitioners. All patients, with the exception of those with minor ophthalmic problems, were screened for hypertension and glycosuria. The patients were subsequently referred to their general practitioner or the appropriate hospital specialist for further management. RESULTS: During this period 1025 new patients visited the emergency eye clinic. Previously undiagnosed systemic disease was present in 86 patients (8.4%). The commonest disorders were neurological 35 (41%), cardiovascular 17 (20%), glycosuria 13 (15%) and respiratory 5 (6%). Visual disturbance and pain were the most frequent ocular presentation. In 54 patients (62.8%) the ocular condition was a direct manifestation of the systemic condition and in 32 patients (37.2%) the systemic disease was a coincidental finding. CONCLUSIONS: Awareness of ophthalmological manifestations of systemic disorders helps in the early diagnosis of these conditions and reduces the resulting morbidity and possibly mortality. This study illustrates the hidden role of the emergency eye clinic in identifying patients with an underlying systemic condition.

Brain Diseases↗