Evaluation of a district-wide screening programme for diabetic retinopathy utilizing trained optometrists using slit-lamp and Volk lenses.

BACKGROUND: Debate exists about the optimum way to screen for diabetic retinopathy. Cameras produce a permanent record, but offer patients less choice about when and where to be screened. Optometrists offer flexibility but sensitivity and specificity of schemes have varied considerably, perhaps because of variability in screening methodology and that there is frequently no quality assurance programme. AIMS: To audit our district-wide (population 340000) screening programme for diabetic retinopathy against national targets: sensitivity > 80%, specificity > 95% and referral to review < 3 months. METHODS: Trained optometrists performed slit-lamp examination with Volk lenses (78 dioptre) with standardized reporting. Audit was by ophthalmologist with slit-lamp and Volk lenses through dilated pupils. RESULTS: We examined 872 eyes of 439 patients; 64% were normal, 29% background diabetic retinopathy, 7% sight-threatening eye disease (STED). Sixty-three percent of patients were seen within 6 months of the original screen. Of these, sensitivity for any retinopathy was 72%, specificity 77%, positive predictive value (PPV) 53%, negative predictive value (NPV) 88%. For STED, in this group, sensitivity was 87% and specificity 91%, PPV 30%, NPV 99%. Median interval referral to ophthalmological review was 11.5 weeks with 73% reviewed in under the 13-week target. Of those referred 25% received laser therapy. Eleven patients found to have referable eye disease at their initial screen were not referred to an ophthalmologist by their GP. CONCLUSIONS: We conclude that effective district-wide screening for diabetic retinopathy by optometrists using slit-lamp and Volk lenses is possible; however, only 36% of identified people with diabetes in the district were screened over a 4-year period.

Effect of anionic salts in prepartum diets based on alfalfa.

This study compared prepartum diets based on grass, alfalfa, or alfalfa and anionic salts to investigate their effect on Ca metabolism, acid-base status, endocrine response, disease incidence, and lactational performance of periparturient dairy cows. Forty-five nonlactating Holstein cows in their last 3 wk of gestation were fed a control diet based on grass hay with a dietary cation-anion difference [expressed as milli-equivalents of ((Na + K) - (Cl + S))/100 g of dietary dry matter] of +30 or diets based on alfalfa with a dietary cation-anion difference of either +35 or -7. Cows fed the diet with the dietary cation-anion difference of -7 had the lowest urine pH prepartum and had the highest concentrations of ionized Ca in blood and total Ca in serum at parturition. Increases in 1,25-(OH)2 vitamin D per unit decrease in total Ca in serum were greatest for cows fed the diet with a dietary cation-anion difference of -7. Also, cows fed this same diet consumed the most dry matter postpartum. Incidences of health disorders were 13% (10 of 75), 12% (9 of 75), and 5% (4 of 75) for cows fed the diets with dietary cation-anion differences of +30, +35, and -7, respectively. Results indicate that alfalfa, when supplemented with anionic salts, is a viable forage for prepartum dairy cows.

A comparison of amethocaine cream with lignocaine-prilocaine cream (EMLA) for reducing pain during retrobulbar injection.

A prospective, randomised, double-masked, placebo-controlled study was carried out on 169 patients undergoing cataract extraction to compare the topical anaesthetic cream amethocaine with EMLA (eutetic mixture of local anaesthetic, lignocaine and prilocaine) and placebo in reducing pain during retrobulbar injection. Fifty-eight patients received EMLA, 55 amethocaine and 56 the placebo. The pain was assessed objectively by the anaesthetist and subjectively by the patient. Significantly lower pain scores were observed in those patients who had amethocaine (p < 0.001) or EMLA (p < 0.005) in comparison with those who had placebo, but there was no statistical difference between amethocaine and EMLA (p > 0.1; t-test). No systemic or local side-effects were encountered in any group.

Comparative evaluation of the Allergan Humphrey 570 and Canon RK-1 autorefractors: I. Objective autorefraction in normal subjects.

Fifty normal subjects were studied comparing objective autorefraction using the Allergan Humphrey 570 (AH 570) and Canon RK-1 autorefractors in terms of ease of operation, the time taken and their accuracy compared with clinical refraction. Both the autorefractors were equally easy to operate but the AH 570 was quicker. Objective autorefraction with the AH 570 was more accurate than using the Canon RK-1 especially with respect to spherical equivalence, sphere power and cyclinder axis: approximately 80% of the values were within 0.51 dioptres or 11 degrees of clinical refraction compared to approximately 60% for the Canon RK-1. The possible reasons for the superior performance of the AH 570 are discussed.

Comparative evaluation of the Allergan Humphrey 570 and Canon RK-1 autorefractors: II. Objective autorefraction in pseudophakes.

Fifty patients (50 eyes) with posterior chamber intraocular lenses and a best corrected visual acuity of at least 6/12 were studied. The Allergan-Humphrey 570 (AH-570) and Canon RK-1 autorefractors were compared in terms of ease of operation, time taken and their accuracy relative to clinical refraction. Both the autorefractors were equally easy to operate but the AH-570 was quicker. The AH-570 had a higher percentage of eyes within 11 degrees of clinically determined cylinder axis while the Canon RK-1 had a higher percentage of patients within 0.51 diopters of spherical equivalence, sphere power and cylinder power as determined by clinical refraction. This difference in the accuracy of objective autorefraction was not statistically significant; the clinical significance is uncertain.

Glare testing in pseudophakes with posterior capsule opacification.

We measured Snellen visual acuity under standard and glare conditions using the Allergan Humphrey 570 autorefractor in 46 pseudophakes (46 eyes) undergoing Neodymium-YAG laser posterior capsulotomy before and after treatment. All the patients studied had a best corrected vision of at least 6/12 but complained of visual disability and had clinically observable posterior capsule opacification. The patients did not have other known causes of glare disability. Following posterior capsulotomy, 30 (65%) patients showed an improvement in standard Snellen visual acuity and 44 (97%) an improvement in Snellen visual acuity under glare conditions. This difference was statistically significant (p < 0.001). Of the 16 patients whose standard Snellen visual acuity did not improve after posterior capsulotomy, 14 showed a reduction in glare disability. Glare testing was clinically useful in evaluating pseudophakes with posterior capsule opacification who complained of visual disability in spite of good Snellen visual acuity under standard testing conditions.

Solitary extramedullary plasmacytoma of the maxillary antrum and orbit presenting as acute bacterial orbital cellulitis.

Orbital involvement by plasma cell tumours is rare. Orbital tumours do not generally present as an acute orbital inflammatory disease in adults, though tumours such as rhabdomyosarcoma may cause clinical signs similar to an acute orbital cellulitis in children. We describe a patient with bacterial orbital cellulitis and sinusitis who was found to have an extra-medullary plasmacytoma of the maxillary antrum and orbit and coexisting testicular seminoma.

A double-masked evaluation of lignocaine-prilocaine cream (EMLA) used to alleviate the pain of retrobulbar injection.

A randomised, placebo controlled, double-masked study was undertaken in 115 patients undergoing cataract surgery to assess the efficacy of the anaesthetic cream EMLA (eutetic mixture of local anaesthetic, lignocaine-prilocaine) in alleviating the pain of retrobulbar injection. Sixty three patients received the EMLA cream and 52 the placebo cream. The pain was assessed objectively by the anaesthetist, who observed the reaction of the patient on needle insertion, and subjectively by the patient. Significantly lower pain scores were recorded in patients treated with EMLA cream (anaesthetist's observation: p less than 0.01, patient's assessment: p less than 0.006). No patients experienced serious side effects in either treatment group.

Comparison of the effect of acetazolamide tablets and sustets on diurnal intraocular pressure in patients with chronic simple glaucoma.

Twenty patients with primary open-angle glaucoma uncontrolled on single topical therapy completed a double dummy crossover study to compare acetazolamide tablets with a sustained release formulation (Sustet). The two preparations were equally effective, but no direct relationship was found between the intraocular pressure and the plasma concentration of acetazolamide. No difference between the formulations was found in the frequency or severity of side effects.

New cystotome for intercapsular cataract procedures.

Intercapsular cataract extraction, a variation of extracapsular cataract extraction (ECCE), has recently become popular, particularly in Europe and Asia. It is gaining popularity in the United States among both phacoemulsification and planned ECCE surgeons. The initial steps in the intercapsular capsulotomy include either a linear or curvilinear opening. To facilitate anterior capsulotomy for intercapsular surgery, we developed a disposable 27-gauge cystotome with a specially designed curved configuration. This cystotome also facilitates capsulotomies in deep-set eyes, which may be difficult when standard cystotomes are used. The new cystotome has a conventional beveled tip with a 90-degree bend and a main shaft curved at a radius of 14.5 mm. When attached to a syringe this cystotome allows the surgeon a more comfortable holding position during the capsulotomy procedure.

Syphilitic retinitis in a homosexual man with concurrent HIV infection: case report.

A case is reported of secondary syphilis with ocular signs in a patient who had antibodies to human immunodeficiency virus (HIV) and hepatitis B infections and from whose urine cytomegalovirus was cultivated. Treatment with penicillin resulted in rapid recovery from his retinitis and uveitis. The case highlights the importance of testing for syphilis in all patients with HIV infection.

Equivalence of conventional and sustained release oral dosage formulations of acetazolamide in primary open angle glaucoma.

1. Outpatients with primary open angle glaucoma uncontrolled on single topical therapy with either pilocarpine or timolol were recruited for a stratified double dummy cross over trial. Once or twice daily sustained release acetazolamide (SRA) was compared with an identical regimen of conventional tablets (CA). 2. During the run in period the patients received 500 mg SRA once or twice daily as needed to control intraocular pressure (IOP). The dose was thereafter kept constant and patients were allocated randomly to 4 weeks treatment with CA followed by 4 weeks SRA or vice versa. IOP and venous plasma concentrations of acetazolamide were measured at weekly intervals. At the end of each 4 week course, patients were admitted for a 24 h profile of IOP and drug concentration measurements. 3. Thirty-five patients were recruited, but eleven were withdrawn during the run in period largely because of adverse effects; these became less troublesome when it was decided to give the once daily dose at 22.00 h. Four were withdrawn during the cross over, two because of inadequate IOP control. Twenty completed the trial. 4. The morning plasma concentration of acetazolamide measured each week showed no tendency to accumulation during the study. The mean swing (maximum minus minimum) in plasma acetazolamide concentration during the 24 h profile was less (P less than 0.005) with the SR formulation (11.6 +/- 4.9; mg l-1) +/- s.d.) than with the conventional (15.5 +/- 4.7) but the mean concentrations over the 24 h profile were indistinguishable (P greater than 0.05; 9.7 +/- 3.8 and 8.6 +/- 2.8 respectively). 5. Satisfactory control of IOP (no more than one reading above 22 mmHg) was maintained despite the changes in formulation in all but two of the patients who entered the cross over study. No close relationship between IOP and plasma concentration of acetazolamide was found. The 24 h IOP profiles whilst receiving each of the formulations were indistinguishable; thus the smoothing of the plasma drug concentration profile achieved by the SR formulation did not reduce the amplitude of swings in IOP. Similarly, no difference was observed between the formulations with respect to adverse effects. 6. It is concluded that the SR and conventional formulations were equivalent with respect to mean plasma acetazolamide concentration, IOP control and adverse effects. The SR formulation did not show practical advantages over the conventional formulation which was equally effective even with dosage intervals of 12 or 24 h.

Giant intracranial aneurysms simulating brain neoplasms on computed tomography.

Giant intracranial aneurysms (GIA) may simulate brain neoplasms on computed tomography (CT) scans. We present three cases in which a GIA was mistakenly diagnosed as a brain neoplasm on the basis of CT findings. The correct diagnosis was made in each case by cerebral angiography. The possibility of GIA must be considered when a nonenhanced CT study shows a well circumscribed mass without edema at the base of the brain and contrast infusion reveals homogeneous or inhomogeneous enhancement.