Recent developments in eye surgery
In the last two decades, eye surgery has
become a micro-surgical speciality. Cataract surgery has been transformed by
changes in local anaesthesia, implants, phakoemulsification and small incision
surgery which allows compressible silicone or acrylic implants to be inserted
through a 3-mm incision. The implant power can be more accurately measured by
new formulae and the use of A-Scan ultrasonography.
The
developments in vitreous surgery have enabled membranes to be peeled off the
retina and macular holes to be repaired and have also increased the success rate
in retinal detachment surgery with the additional use of gases and silicone oil
inserted into the vitreous cavity.
Some
paralytic squints can be helped by the use of adjustable sutures or injections
of botulinum toxin into the overacting muscles. Refractive error can be treated
either by surgery (radial keratometry) or by the excimer laser. This can be
combined
with LASIK surgery (laser in situ keratomeilusis)
which involves removing a cornea) flap and doing the laser surgery at a deeper
level. There have been some concerns about defective contrast sensitivity and
problems with night vision after laser correction of myopia. Phakic implants
have also been used to correct high refractive errors.
Corneal
topography can help in making corneal and refractive surgery more accurate, and
the increased use of CT and MRI scans helps to diagnose orbital and intracranial
lesions involving the optic pathways (Fig 36.35—Fig
36.37). Fluorescein
angiography and indocyanine green angiography
help in the diagnosis and occasional treatment
of macular lesions. The only advantage of indocyanine green is that the
vascularisation of the choroid is much easier to see.