Learn Together - Seeing Eyes

Very-Low-Dose Atropine Drops Slow Myopia Progression in Children

2011-11-03T06:38:00.000+08:00

http://www.medscape.com/viewarticle/752549

NEW YORK (Reuters Health) Oct 28 - Eye drops of 0.01% atropine control myopia progression in children almost as effectively as 1.0% atropine drops, but with minimal adverse effects, according to a new report in Ophthalmology.

"Atropine 0.01% is currently not commercially available. However, these findings collectively suggest that a nightly dose of atropine at 0.01% seems to be a safe and effective regimen for slowing myopia progression in children, with minimal impact on visual function," said Dr. Donald Tan, with the Singapore National Eye Center, and colleagues in an October 1st paper.

According to the authors, randomized trials -- including one of theirs - have shown that eye drops with atropine in concentrations of 1.0% and 0.5% can slow myopia progression, but effects on pupil size and accommodation have been a drawback.

To find a better balance between efficacy and adverse effects, the team randomly assigned 400 children, ages six to 12 and with myopia of at least -2.0 diopters, to nightly administration of 0.5%, 0.1% or 0.01% atropine in both eyes for two years.

Initially, the researchers explain, the lowest dose was intended to serve as a control as it was assumed to be ineffective, but this turned out not to be the case.

Mean myopia progression at two years in the three groups was -0.30, -0.38, and -0.49 D, respectively, Dr. Tan and colleagues found. By comparison, in their previous study, two-year progression was -0.28 D with 1.0% atropine and -1.20 D with placebo.

The authors say the between-groups difference of 0.19 D in myopia progression in the current study is clinically insignificant. On the other hand, 0.01% atropine had negligible effects on pupil size and accommodation.

Furthermore, the most common adverse effect -- allergic conjunctivitis and dermatitis -- occurred in 16 patients in the 0.5% and 0.1% groups, but in none of the children in the 0.01% arm, the report indicates

Summing up, the team concludes that 0.01% atropine "is a viable concentration for reducing myopia progression in children, while attaining a clinically significant improved safety profile in terms of accommodation, pupil size, and near visual acuity, and subsequently reduced adverse impact on visual function."

SOURCE: http://bit.ly/t16WB0

Ophthalmology 2011.

Short notes retinitis pigmentosa

2011-10-29T05:09:00.001+08:00

Retinitis pigmentosa

Degeneration of rod

Symptom: night blindness and difficulty in dark adaptation
5 in 1000 in population

Sign: initially symptomatic only. Then will have bony spicules pigmentation innretina, initially at equator, then will extend to anterior and posterior. Retinal vessel will become attenuated, then optic disc becoming paler till become waxy appearance optic atrophy.
Late complication, pt can also have tubulur vision.

Association with other disease:

Ocular
- high myopia
- POAG
- microphthalmus
- conical cornea
- posterior subcapsular cataract.

Systemic association:
1. Laurence moon biedl syndrome
- retinitis pigmentosa, obesity, hypogenitalism, polydactyly and mental deficiencies.
2. Cockcaney syndrome - retinitis pigmentosa,infantile deafness, mental retardation, dwarfism nystagmus, ataxia.
3. Refsum syndrome - retinitis pigmentosa, cerebellar ataxia, peripheral neuropathy,
4. Usher syndrome - retinitis pigmentosa, labyrinthine deafness.
5. Hallgren,s syndrome- retinitis pigmentosa, vestibulocerebellar ataxia, congenital deafness, mental retardation.

Atypical retinitis pigmentosa better than typical retinitis pigmentosa.

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Sudden painless loss of vision

2011-06-28T09:59:00.000+08:00

in 85 y/o lady, initially of her right eye five days ago and today of her left eye.

Clue: look closely at the OD

What is the pathology of OD?
What could possibly be the diagnosis?

Source: Kellogg Eye Centre

Answer:

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Pathology: OD infarction
You are looking at a swollen optic disc. Its axoplasm has been stopped by ischemia. In this case, there has been inflammatory occlusion of the ciliary feeder vessels of the optic nerve, a common finding in giant cell arteritis. The visual loss is irreversible.

The patient experiences sudden, painless, and usually devastating loss of vision in one eye. Most individuals are aged over 70 years and have a combination of limb girdle myalgias, fever, and lassitude. These symptoms are part of a syndrome called "polymyalgia rheumatica," an idiopathic autoimmune disorder of the elderly. Other patients describe scalp tenderness and pain with chewing, manifestations of external carotid artery ischemia.

The diagnosis is further suggested by finding an elevated sedimentation rate or C-reactive protein and confirmed by finding granulomatous inflammation in scalp (usually temporal) arteries on biopsy.

The diagnosis must be made immediately because there is a strong chance that the fellow optic nerve will become infarcted within days unless high-dose corticosteroid treatment is begun. This treatment is nearly 100% effective in preventing second eye involvement.

What to do?

Acute, persistent monocular visual loss in an elderly patient must be presumed to be caused by giant cell arteritis, especially if constitutional symptoms are present. If you find a swollen disc, that presumption rises astronomically.