Surgical interventions for bilateral congenital cataract

BACKGROUND

Congenital cataracts are opacities of the lens in one or both eyes of children, causing a reduction in vision bad enough to require surgery. Cataract is the largest preventable cause of visual loss in childhood. Paediatric cataracts provide different challenges to those in adults. Intense inflammation, amblyopia and posterior capsule opacification can affect results of treatment. Two treatments commonly considered for congenital cataract are lensectomy and lens aspiration.

OBJECTIVES

The objective of this review is to assess the effects of surgical treatments for bilateral symmetrical congenital cataracts. Success is measured according to the vision attained and occurrence of adverse events.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register - CENTRAL (which includes the Cochrane Eyes and Vision Group specialised register), MEDLINE, EMBASE, the Science Citation Index and the reference list of the included study. We also contacted trial investigators and experts in the field for details of further studies.

SELECTION CRITERIA

We included all prospective, randomised controlled trials that compared one type of cataract surgery to another or to no surgery, in children aged 15 years or younger with bilateral congenital cataracts.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data. No meta-analysis was performed.

MAIN RESULTS

One trial met the inclusion criteria. This trial randomised 130 eyes of 65 children. Follow up of 56 children at three years found no difference in visual acuity between lensectomy and lens aspiration with primary capsulotomy. Secondary opacification developed at a higher rate in the lens aspiration group (66%) compared to the lensectomy group (2%).

REVIEWER'S CONCLUSIONS

The two methods of surgery for bilateral congenital cataracts in this review have good visual results but the incidences of side effects differ. Further randomised trials are required to inform modern practice.

Natural history of diabetic macular streak exudates: evidence from a screening programme

BACKGROUND/AIMS

Diabetic retinopathy screening guidelines recommend referral to an ophthalmologist if there is exudate within one disc diameter of the fovea. Many of these patients, however, have resolution of small amounts of exudate without treatment. This study aimed to assess whether patients with minimal streak or dot exudates within one disc diameter of the fovea can be monitored in a screening programme without compromising visual acuity.

METHODS

A retrospective review of records and Polaroid photographs obtained by one screening centre over a 10 year period was performed. Outcomes measured were referral rates, alteration of Snellen visual acuity, and the need for macular photocoagulation treatment.

RESULTS

55 patients (74 eyes) fulfilled entry criteria (37 streak and 37 dot exudates). Mean follow up was 56.1 months (range 12-127 months). Twenty five patients (30 eyes) were referred to an ophthalmologist. 13 eyes (17.6%) required macular photocoagulation treatment. Four eyes (5.4%) lost two or more lines of Snellen acuity over the follow up period (three from macular oedema and one from macular ischaemia). There was no relation between the presence or resolution of minimal exudate and visual loss (p>0.2).

CONCLUSION

It is appropriate to monitor eyes with streak or dot macular exudates at 6-9 monthly intervals in a screening programme.

Lipophilic versus hydrophilic beta(1) blockers and the cardiac sympatho-vagal balance during stress and daily activity in patients after acute myocardial infarction

OBJECTIVE

To compare the effects of a lipophilic and a hydrophilic beta(1) blocker on cardiac sympatho-vagal balance during daytime activity and stress in patients four to six weeks after myocardial infarction.

DESIGN

Randomised, double blind, crossover study comparing the effect of atenolol (50 mg once daily) with metoprolol CR (100 mg once daily) with treatment periods of four weeks.

SETTING

Large teaching hospital.

PATIENTS

50 patients (45 male, 5 female, age range 40 to 75 years), four to six weeks after an acute myocardial infarction.

METHODS

At the end of each treatment period the 24 hour heart rate variability, heart rate variability power spectra during head up tilt and mental stress, baroreflex sensitivity, and exercise performance were evaluated.

RESULTS

During daytime activity and during orthostatic and mental stress, both heart rate and the ratio between the low and high frequency spectral components of the heart rate variability were significantly lower with atenolol. Conversely, there was no difference between treatments in baroreflex sensitivity and resting plasma catecholamines. Exercise duration and peak oxygen consumption did not differ between treatments, but the heart rate during submaximal and peak exercise was significantly lower with atenolol.

CONCLUSIONS

At the doses used in this study, atenolol achieved greater beta(1) adrenergic blockade than metoprolol CR and this was associated with significant inhibition of vagal withdrawal during stress. This suggests that peripheral blockade of beta(1) adrenergic receptors may be more important than central blockade in preventing stress induced vagal withdrawal in patients after myocardial infarction.

Time-related hemodynamic changes after aortic replacement with the freestyle stentless xenograft

BACKGROUND

The Freestyle valve is a porcine aortic root fixed with net zero pressure across the cusps and treated with the anticalcification agent alpha-aminooleic acid. We evaluated the hemodynamic function of this stentless valve.

METHODS

We implanted the valve into 80 consecutive patients scheduled to receive a bioprosthesis. Sixty-nine patients were more than 70 years old and 14 had calcified aortic sinuses. The "cylinder within a cylinder" implantation technique was used. Twenty-seven patients received coronary grafts, and 3 had mitral repair. All patients were studied echocardiographically during week 1 and 41 were studied at 6 months.

RESULTS

Median ischemic time for isolated aortic valve replacement was 44 minutes. There were four hospital deaths, none valve related. No patient had more than trivial aortic regurgitation. Mean systolic gradients for valve sizes 21 to 25 mm fell significantly with time (p < or = 0.05) due to remodeling of the porcine root and early regression of left ventricular hypertrophy. Late hemodynamic function was equivalent to an aortic homograft.

CONCLUSIONS

The Freestyle valve is easily implanted and has excellent hemodynamics. Transvalvular gradients decrease progressively.