·
Advances in
LASIK. Recently many advances have been made in LASIK surgery. Some
of the important advances are:
Customized (C) LASIK. C-LASIK is based
on the wave front technology. This technique, in addition to spherical and
cylindrical correction, also corrects the aberrations present in the eye and
gives vision beyond 6/6 i.e., 6/5 or 6/4
Epi-(E) LASIK. In
this technique instead of corneal stromal flap only
the epithelial sheet is separated mechanically with the use of a customized
device (Epiedge Epikeratome).
Being an advanced surface ablation procedure, it is devoid of complications
related to corneal stromal flap.
·
Recently, promising results are reported with adenine arabinoside (Ara-A) IN Rx of Epidemic Keratoconjunctivitis
(EKC).
·
Recently VKC or Spring Cattarh
is being labelled as 'Warm
weather conjunctivitis'.
·
Topical
cyclosporine (1%) drops have been recently reported to be effective
in severe unresponsive cases of VKC.
·
Recently described treatment modality
include topical nerve growth factor drops and amniotic membrane
transplantation in Neuroparalytic keratitis.
·
Recently, lot of stress is being laid on the role of HLA in uveitis,
since a number of diseases associated with uveitis
occur much more frequently in persons with certain specific HLA-phenotype. A
few examples of HLA-associated diseases with uveitis
are as follows:
HLA-B27.
Acute anterior uveitis associated with ankylosing spondylitis and also
in Reiter’s syndrome.
HLA-B5: Uveitis
in Behcet’s disease.
HLA-DR4 and DW15: Vogt Koyanagi Harada’s disease.
·
There is no specific treatment of CID (CYTOMEGALIC INCLUSION DISEASE). Recently
treatment with intravenous dihydroxypropylmethyl guanine has been shown to cause regression in
some cases.
·
Nerve fibre layer analyzer (NFLA) is a recently
introduced device which helps in detecting the glaucomatous damage to the
retinal nerve fibres before the appearance of actual
visual field changes and/or optic disc changes.
·
Spindle cell
theory proposed recently for ROP postulates the induction of retinal
and vitreal neovascularization
by spindle cell insult in a premature retina.
·
The following scheme
for the pathogenesis of Graves’ ophthalmopathy has
been recently proposed:
1.
Circulating T cells in patients with Graves’
disease directed against an antigen on thyroid follicular cells,
recognize this antigen on orbital and pretibial
fibroblasts (and perhaps extraocular myocytes). How these lymphocytes came to be directed
against a self-antigen, escaping deletion by the immune system, is unknown.
2.
The T cells then infiltrate the orbit and pretibial skin. An interaction between the activated CD4 T
cells and local fibroblasts results in the release of cytokines into the
surrounding tissue – in particular, interferon-interleukin-1, and tumor
necrosis factor.
3.
These or other cytokines then stimulate the
expression of immunomodulatory proteins (the 72-kd
heat-shock protein, intercellular adhesion molecules, and HLA-DR) in orbital
fibroblasts, thus perpetuating the autoimmune response in the orbital
connective tissue.
4.
Furthermore, particular cytokines (interferon-,
interleukin-1, transforming growth factor, and insulin-like growth factor 1)
stimulate glycosaminoglycan production in
fibroblasts, proliferation of fibroblasts, or both, leading to the accumulation
of glycosaminoglycans and oedema
in the orbital connective tissue. In addition, thyrotropin-receptor
or other antibodies may have direct biological effects on orbital fibroblasts
or myocytes; alternatively, these antibodies may
reflect the on going autoimmune process.
5.
The increase in connective-tissue volume and the
fibrotic restriction of extraocular-muscle movement
resulting from fibroblast stimulation lead to the clinical manifestations of ophthalmopathy. A similar process occurring in the pretibial skin results in the expansion of dermal
connective tissue, which in turn leads to the nodular or diffuse skin
thickening characteristic of pretibial dermopathy.
No comments:
Post a Comment