Clear- sighted so­lu­tions to those morn­ing fum­bles

The Weekend Australian - Review - - Laser Eye Surgery - By LAURA CENCIGH

WAK­ING up in a blurry room and fum­bling for our glasses on the bed­side ta­ble is the way many of us start our day. Ac­cord­ing to Op­tometrists As­so­ci­a­tion Aus­tralia sta­tis­tics, over 480,000 Aus­tralians are vis­ually im­paired in both eyes.

While some em­brace their glasses as a fash­ion ac­ces­sory, a grow­ing num­ber are turn­ing to laser tech­nol­ogy in the hope of ditch­ing the specs for good.

It’s a tempt­ing op­tion, con­sid­er­ing that over half of th­ese vis­ual im­pair­ments are eas­ily cor­rectable.

A ma­jor­ity are due to re­frac­tive er­ror, which re­late to the fo­cus­ing of light.

LASIK, to­day’s most pop­u­lar form of laser eye surgery, has be­come an in­creas­ingly re­li­able, pre­dictable and safe method of cor­rect­ing re­frac­tive er­ror over the past 15 years.

Along with other tech­no­log­i­cal ad­vance­ments, LASIK’s rise in pop­u­lar­ity has been aided by the will­ing­ness of high profile fig­ures, such as Tiger Woods and Jes­sica Simp­son, to put them­selves be­fore the beam.

Royal Aus­tralian and New Zealand Col­lege of Oph­thal­mol­o­gists ( RANZCO) pres­i­dent, Dr Iain Dun­lop, says tech­no­log­i­cal ad­vance­ments have opened up the pro­ce­dure to a broader range of peo­ple.

He says: Laser is much more so­phis­ti­cated now. It has moved from ex­per­i­men­tal to main­stream.’’

When it was first de­vel­oped, LASIK was only able to treat my­opia or short- sight­ed­ness.

It re­mains most suc­cess­ful for sim­ple low sever­ity short- sight­ed­ness, but is now a rea­son­ably suc­cess­ful treat­ment for mid­dle sever­ity long sight­ed­ness ( hy­per­opia) and astig­ma­tism.

For pa­tients who fall into the for­mer cat­e­gory, there is a 90 per cent chance of achiev­ing at least 6/ 12 vi­sion, which is the le­gal re­quire­ment for driv­ing in most Aus­tralian states.

This means that at six me­tres, a pa­tient will see the same as what a per­son with nor­mal vi­sion sees at 12 me­tres ( the met­ric equiv­a­lent to 20/ 20 vi­sion).

To be el­i­gi­ble for the surgery, pa­tients must also be be over 18, and their eye pre­scrip­tion should have been stable for two years. Oth­er­wise, if their eyes are still chang­ing, they may be over­cor­rected and re­quire fur­ther surgery.

One of the fac­tors con­tribut­ing to the broader ap­pli­ca­tion of LASIK surgery is the de­vel­op­ment of a laser used to cut through the outer layer of the cornea, the eye’s win­dow’’.

To be­gin the pro­ce­dure, the sur­geon cuts a tiny flap in the cornea to al­low a laser to re­shape the tis­sue un­der­neath. The flap is then placed back over the treated area.

Ini­tially, a high- speed blade was used to cre­ate this flap, but now a fast, com­puter- guided laser, known as a fem­tosec­ond laser or, by brand name, as In­traLase, is avail­able. Dr Dun­lop es­ti­mates that over one quar­ter of clin­ics now use the lat­ter tech­nol­ogy, and ex­pects the roll- out to con­tinue.

The fem­tosec­ond has the abil­ity to make dif­fer­ent shapes and dif­fer­ent types of flaps,’’ he says. It’s safer and more adapt­able.

Nowa­days you can treat long- sight­ed­ness and astig­ma­tism and ab­nor­mal shapes more suc­cess­fully.’’

While LASIK has gained pop­u­lar­ity over the last decade, prior to that, a pro­ce­dure called PRK ( pho­tore­frac­tive ker­ac­tec­tomy) was the most com­mon.

In this tech­nique, the sur­geon scrapes off a thin layer of the cornea, rather than cut­ting a flap. A laser is then used to re­shape the sur­face of the cornea. The sur­face cells do grow back and usu­ally heal within three to five days, but sig­nif­i­cant dis­com­fort can re­sult in the mean­time.

With LASIK, on the other hand, the eyes usu­ally feel quite com­fort­able the day af­ter surgery, and pa­tients can re­sume most nor­mal ac­tiv­i­ties.

There is, how­ever, a small ad­di­tional risk of sur­gi­cal com­pli­ca­tions with LASIK which are not as­so­ci­ated with PRK.

Pho­tother­a­peu­tic Ker­ac­tec­tomy ( PTK) uses a sim­i­lar pro­ce­dure to PRK, but is used for the re­moval of sur­face ir­reg­u­lar­i­ties on the cornea.

The main risks of re­frac­tive laser surgery are in­fec­tion and scar­ring, but, ac­cord­ing to Dr Dun­lop, the risk of those oc­cur­ring is now less than one in 5000: ‘‘ It has a very broad ac­cep­tance,’’ he says. ‘‘ It’s very safe in med­i­cal terms, but it is still dis­cre­tionary, and with dis­cre­tionary surgery, even small risks are con­sid­ered sig­nif­i­cant.’’

In terms of side- ef­fects, the most com­mon are blur­ring, glare, ha­los, light sen­si­tiv­ity and un­com­fort­ably dry eyes.

Most of th­ese com­pli­ca­tions can be fixed with ex­tra treat­ment or ex­tra time,’’ Dr Dun­lop says.

For short- sighted peo­ple, un­der­go­ing laser eye surgery in­creases the prob­a­bil­ity of them need­ing read­ing glasses in later life.

As Shirley Loh, pro­fes­sional ser­vices man­ager for the Op­tometrists As­so­ci­a­tion Aus­tralia ex­plains: Your eyes are be­ing changed to be­come closer to nor­mal sight, and like ev­ery other per­son with nor­mal vi­sion, there’s a chance you will need read­ing glasses when you get older.’’

But, if you have the surgery at 25, this still means 15 to 20 years of clear vi­sion. One op­tion is to get one eye made for dis­tance and one eye for short sight, but not many peo­ple can adapt to this,’’ Ms Loh says.

There’s no per­fect so­lu­tion out there, ev­ery­thing has its ad­van­tages and disad­van­tages.’’

Aside from the treat­ment of re­frac­tive er­rors, lasers can also be used to treat a num­ber of eye dis­eases and con­di­tions. One of th­ese is wet mac­u­lar de­gen­er­a­tion. The con­di­tion in­volves blood ves­sels grow­ing into the mac­u­lar ( a small, cen­tral area of the eye’s retina) and leak­ing blood and fluid.

Th­ese flu­ids build up un­der the retina and, even­tu­ally, scar tis­sue forms which se­verely de­te­ri­o­rates vi­sion.

Un­like re­frac­tive pro­ce­dures which re­shape the cornea, treat­ment for this con­di­tion in­volves a laser which goes through the cornea to burn the ab­nor­mal blood ves­sels in the mac­u­lar.

With con­di­tions such as glau­coma, the laser is used to make ad­di­tional holes to en­able drainage and ease pres­sure in the eye.

In both cases, the surgery will not re­store vi­sion al­ready lost, but will help pre­serve the eye from any fur­ther de­gen­er­a­tion.

Un­for­tu­nately for the many peo­ple whose vi­sion starts to go down­hill as they move to­wards their se­nior years, laser tech­nol­ogy is yet to de­liver a widely suc­cess­ful rem­edy for pres­by­opia.

This con­di­tion re­lates to the age­ing eye’s loss of the flex­i­bil­ity needed to switch fo­cal points be­tween close and dis­tant ob­jects.

Dr Dun­lop de­scribes the search for a treat­ment for this con­di­tion as a holy grail’’ quest.

There’s a lot of work be­ing done try­ing to re­place that func­tion of that mus­cle or to do what it does in other ways,’’ he says. It has been a pur­suit over at least the last 20 years.’’

He says that im­plant lens tech­nol­ogy, com­bined with laser, is one of the most promis­ing meth­ods. While this is presently avail­able, a num­ber of side- ef­fects make the method un­de­sir­able to all but a small per­cent­age of suf­fer­ers ( about one per cent).

There are many com­pro­mises that peo­ple have to ac­cept,’’ Dr Dun­lop says. They lose their con­trast and have a vague sense of dou­ble im­age wher­ever they look.

Un­til th­ese com­pro­mises can be re­duced or bet­ter man­aged, it won’t be­come wide­spread. At the mo­ment, multi- fo­cal glasses or read­ing glasses are still the best cor­rec­tion for that.’’

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