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Surgical Simon G. Levy MD, MRCP, FRCS, FRCOphth

The College of Optometrists has awarded this article 2 CET credits. There are ✓ 12 MCQs with a pass mark

The College of of 60%. LASIK Optometrists

LASIK has revolutionised refractive surgery and is a quantum improvement over previous methods. This article will explain why.

Indications as long as 18 months before the patient and Laser in-situ keratomilieusis (LASIK) is surgeon know where they stand vis-à-vis the indicated to treat myopia and myopic need for enhancement. An enhancement is a astigmatism, hyperopia and hyperopic relatively patient-friendly event in the astigmatism1,2. It also has a role in treating context of LASIK. The flap is lifted (this presbyopia by inducing monovision. The requires special instrumentation – the precise level of ametropia that LASIK treats patient is not able to inadvertently shift the is a matter of debate within the refractive flap except within a short period of the community, and to some extent depends on original surgery by rubbing very hard) and individual surgeon preference, idiosyncrasies further laser is applied. This may be done as of the different laser systems available and soon as a month after the original procedure clinical features specific to individual and, as previously, causes no pain. Compare patients. I take a somewhat conservative this enhancement experience with the approach and prefer not to treat more than situation pertaining to PRK. It is necessary about 11 dioptres of combined sphere and to wait at least six months for the refraction cylindrical correction for myopia, and about to stabilise. The patient must then endure 5 dioptres of sphere and 3 dioptres of the ‘normal’ post-operative PRK experience, cylindrical correction for hyperopia. Other namely a period of pain followed by a period approaches are necessary for patients who Figure 1 of blurred vision and the possibility that fall outside these approximate guidelines. A happy LASIK patient regression will once again occur. The risk of For example, for a patient with 20 dioptres haze (corneal scarring) is very low after of myopia, the choice lies between a phakic myopic LASIK, whereas this is by no means intraocular lens and a clear lensectomy. procedure compared to LASIK in the last two the case with PRK. Furthermore, although The majority of patients undergoing or three years. This is because LASIK is haze is more likely to occur after PRK for LASIK have refractive error but perfectly generally preferred by both refractive higher corrections, its onset is normal eyes. However, an important and surgeons and patients. The proof of this is unpredictable, probably because some burgeoning group consists of those who the phenomenal growth in the volume of patients mount a fierce healing response. have a ‘medical’ justification for undergoing LASIK surgery around the world but There is no way of predicting who such refractive surgery. Such circumstances especially in North America where it is patients will be other than by operating on include old style, extracapsular cataract estimated that between 1 and 1.5 million one eye. The need to treat haze and reduce surgery with an unsatisfactory refractive LASIK procedures will be performed this year regression in patients who have had PRK outcome, penetrating keratoplasty, high (Figure 1). may necessitate the use of a topical steroid myopes (within the LASIK range) who have For many refractive surgeons, the list of for six months or even longer with all the become contact lens intolerant, previous indications for PRK is steadily shrinking as attendant risks and unpleasantness, not the radial keratotomy and previous retinal that for LASIK simultaneously expands. least of which is its bad taste. By contrast, detachment with myopia induced by the Often, PRK is used mostly as a LASIK patients rarely require post-operative encircling band used to compress the retina. phototherapeutic keratectomy (PTK) rather medication for longer than one week. Of all the patients in this group, perhaps the than for refractive reasons. PTK is the The disadvantages of LASIK are, of most satisfying to treat are those whose treatment of choice for stabilising the course, that it is a much more sophisticated extracapsular cataract surgery has resulted in corneal epithelium in situations such as surgical technique and that the making of disabling ametropia. Such patients are often recurrent corneal epithelial erosion syndrome the LASIK flap is an extra step in the very aware of the fact that their friends who and for treating superficial corneal scars. procedure during which complications may received phacoemulsification cataract The superiority of LASIK over PRK occur. The main lesson to draw from this is surgery have virtually no refractive error. The becomes evident when the performance of that LASIK is a highly surgical technique use of LASIK to resolve the problem brings the two techniques is compared. LASIK and should be performed only by an relief to both the patient and the original causes no pain, whereas PRK is exquisitely experienced ophthalmologist with cataract surgeon. painful post-operatively for two or three substantial surgical training3. days, notwithstanding the use of LASIK vs PRK unpreserved topical analgesics. Vision Why LASIK and PRK Why patients prefer LASIK returns to near normal within a day or so are different The relationship between these two after LASIK, whereas in PRK vision is very The enormous difference in the techniques in the treatment of refractive blurred for one to two weeks. Furthermore, post-operative behaviour of the two error is currently in flux. A comprehensive whilst there is virtually no regression (loss of techniques stems from the fact that in description of PRK by David O’Brart appeared refractive effect) with LASIK, regression may LASIK there is virtually no disturbance to in the previous instalment in this series (OT be a major problem after PRK. the corneal epithelium and Bowman’s 21/04/00). It is, however, probably true that Six months is an average period for membrane. Instead, after making the flap, PRK has become very much the minority on-going regression after PRK and it may be the laser is applied to the, physiologically www.optometry.co.uk 33 sponsored by ot Surgical

Figures 2 and 3 Graphic showing the technique of LASIK (by courtesy of the Gimbel Eye Centre, Calgary, Canada)

speaking, almost inert corneal stroma both to detect corneal ectasias and to make. It is crucial that the patient leaves the (Figures 2 and 3). In PRK the laser is programme the laser’s computer prior to consultation with a realistic understanding applied directly to the epithelium, one of ablation. Corneal topography is essential to of what is on offer and with sufficient time the two most biologically active regions of exclude ectasias. Contact lens wear must be to contemplate whether this is a course of the cornea (the other being the discontinued before these measurements for action that he or she wishes to pursue. endothelium). Whilst one can laser the a sufficient period for the cornea to resume Unfortunately, common sense advice to avoid corneal stroma almost with impunity, any its true shape. This instruction must be making the patient feel pressured to go trauma to the epithelium stimulates an tempered with realism. Many units ask for ahead with surgery and to allow a ‘cooling- immediate and fierce healing response with one week out of soft lenses, two weeks for off’ period after the consultation is not the resultant difficulties already described. gas permeable lenses and three for PMMA universal practice. The consultation should The exquisite sensitivity of the epithelium lenses. Others insist on serial measurements be a dialogue not a monologue delivered by to pain when it is disturbed is also in of corneal topography or keratometry. the surgeon and it is important that the marked contrast to the complete Corneal pachymetry is essential because the patient has ample opportunity to ask insensitivity of the stroma. ablation depth depends on the required questions. It goes without saying that the dioptric change and enough stroma must be patient should expect the doctor to have Pre-operative consultation left behind after treatment to prevent sufficient seniority to both diagnose any iatrogenic ectasia (see later). disorders precluding treatment and give 1. Clinical assessment A careful history should identify problems accurate answers to any questions asked. LASIK is preceded by a thorough assessment such as amblyopia, previous corneal Specific aspects of refractive correction of the patient’s optical and ocular status. disorders such as herpetic keratitis which discussed are the difference between The required tests included manifest and may be reactivated by laser treatment, distance and near vision, the fact that low cycloplegic refraction, measurement of pupil previous retinal surgery, which makes LASIK myopes may prefer to retain myopia in at diameter in bright and dim light, recording more difficult to perform because the suction least one eye after the age of 40 or so, the of ocular dominance, a cover/uncover test ring may not adhere properly to previously possibility of an enhancement being required and keratometry. Keratometry is necessary disturbed conjunctiva, and systemic diseases for under or over correction and risks (see such as rheumatoid arthritis which may later). In general, my approach is to read impair corneal wound healing post- chapter and verse to the patients so that operatively. Ocular examination is directed they are aware that complications, although Figure 4 toward identifying corneal pathology, such statistically uncommon, do sometimes occur. The suction ring holds the eye still to as keratoconus, which precludes treatment I put it to them that their desire for allow the microkeratome to cut because the ectasia will worsen if the refractive surgery must be sufficiently great already thin cornea is thinned further. for them to undertake some risk. I advise Blepharitis and dry eye will both be patients who are completely risk averse not temporarily worse after LASIK, although they to proceed. are not contraindications to surgery as long as the patient is forewarned. Disorders such How LASIK works as glaucoma and peripheral retinal pathology The microkeratome used to make the LASIK obviously take precedent over refractive flap is assembled and checked. The intended surgery. Retinal examination must be refractive change is entered on the laser’s performed after mydriasis. computer. The patient lies on a comfortable couch and anaesthetic drops are applied. 2. Discussion General or injection anaesthesia are never The pre-operative consultation has typically required in LASIK. The eye is cleaned in the lasted for 45 minutes or longer by the time same way as before cataract surgery. An this phase begins. In some ways, it is the eyelid speculum is applied to prevent most important pre-operative event. The blinking. Radial marks are placed on the patient must be made aware of exactly what cornea so that the flap can be aligned refractive surgery can and cannot achieve accurately when it is replaced after the and of the choices that he or she must ablation.

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A suction ring is applied to hold the eye still (Figure 4) and the microkeratome is then engaged (Figure 5). This sophisticated surgical device splits the cornea into two lamellae. The outer lamella is (depending on the model of microkeratome) about 180um thick and attached by a hinge to the remainder of the cornea. I use the Chiron Hansatome which produces a superiorally- placed hinge which is constantly massaged by blinking (‘down-up LASIK’). The flap is then turned back on itself exposing the stromal bed. At this point, the patient is enjoined to look at the laser’s aiming beam and the ablation is performed (Figures 2, 3, 6 and 7). Figure 6 The laser is applied to the exposed The excimer laser (by courtesy of Bausch & Lomb) stromal bed, not to the flap itself. The exposed stromal surface is appropriately Excimer laser etching on a human hair reshaped, by flattening in myopia and steepening in hyperopia. This typically takes a minute or less so that fixation is not required for very long. The flap is then replaced and floated on to a bubble of fluid. Figure 5 This is a delicate moment since it must be The microkeratome fixed to the suction ring. precisely realigned in its original orientation The cutting blade is covered by the assembly and treated with appropriate respect or it Figure 7 and is not visible in this Figure will stretch and wrinkle. The flap adheres The computer-controlled excimer laser spontaneously to the underlying ablated (by courtesy of Bausch & Lomb) ablation is highly precise (by courtesy of IBM) tissue without needing sutures to keep it in place. The flap being thin will adopt the for two operations rather than one and the reassure him/her that everything is going new shape given to the underlying stromal inconvenience of two sets of post-operative well. Finally, in some units abroad, relatives bed. Therefore, the contour of the surface of visits make unilateral surgery unpopular are invited to hold the patient’s hand the flap will become flatter in myopes with patients. The attitude to risk taken during the procedure. whose stromal beds have been flattened by abroad is basically that the complication the laser. Flattening of the cornea surface rate of LASIK is sufficiently low to justify LASIK trouble-shooting lessens corneal refractive power and so the bilateral approach4. Part of the art of refractive surgery is to corrects myopia. Conversely, in a hyperope identify situations prior to surgery that will whose stromal bed has been steepened, the ÒWill it hurt doctor?Ó lead to a poor outcome. Such surface of the flap will become steeper - How to improve the patientÕs circumstances include unrealistic patient when it is replaced. This increases corneal experience of LASIK expectation of the surgery, for example refractive power and corrects hyperopia. A It is perhaps too much to expect that unwillingness to wear reading glasses combination antibiotic and steroid is patients will enjoy undergoing refractive afterward. Large pupils’ (greater than 8mm) then applied followed by a pad. The surgery, but various steps can be taken to mean glare is to be anticipated procedure takes about 15 minutes in make the event more gentle. These include post-operatively. Corneal pathology such as total. the provision of accurate and informative keratoconus will be worsened disastrously brochures which patients can read before by further thinning of the cornea. Post-operative care the consultation and re-read in the light of Blepharitis and dry eye are worsened, albeit The post-operative phase is minified by the discussion afterwards, free access to temporarily, after LASIK and patients need LASIK. Patients use a combination antibiotic advice from a trained counsellor to whom to be prepared for this. Cornea thickness and steroid drop QID for one week. Vision is questions can be directed, an unhurried measured by pachymetry and the expected sufficiently clear after a day or so for the discussion during the consultation, ablation depth for a given degree of patient to resume normal activity and even preferably with the surgeon who will carry myopia must be correlated so that return to work. There is no pain. Patients out the treatment since this allows the sufficient stroma remains post-operatively are seen at one week, one month and three doctor-patient relationship to form, and the or the patient is at risk of developing months post-operatively. option of discussing refractive surgery with iatrogenic keratoconus. Certain corneal patients who have undergone it previously. geometries make a complication whilst One or both eyes? It is true of all surgery that the better cutting the flap with the microkeratome The reader should be aware that abroad, prepared the patient is beforehand, the less more likely, including those with unusually bilateral simultaneous refractive surgery is traumatising the experience will be. flat (40 dioptres or less) or steep (49 almost universal. The practice of operating There are several ways to allay inevitable dioptres or more) curvature. Very deep-set on one eye at a time that is prevalent in anxiety during the procedure. These include eyes make the surgery more difficult. the UK, is very much the exception not the the availability of a sedative and sitting Finally, the surgeon must identify patients rule. The unilateral approach is based on a with the patient prior to the procedure and in whom there is a large disparity between desire to reduce risk by allowing delayed explaining each step so that the patient the cylinder axis measured by the manifest post-operative complications time to knows exactly what to expect. During the refraction and the corneal cylinder manifest. However, anisometropia, the need procedure, one can talk to the patient and measured by keratometry or corneal

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drive them and greatly increased surgical insufficiently trained surgeon3. It should also experience. be appreciated that complications may follow Presbyopic and pre-presbyopic patients any type of ocular surgery including cataract are well advised to consider monovision extraction. However, patients are frequently with under correction (assuming they are not told about such risks because their myopic) in their non-dominant eye. ophthalmologist considers that the operation Monovision produces the same excellent is ‘essential’ and that there is therefore little results as in the context of contact lens point in worrying the patient about the wear7. Patients are sometimes uncertain inevitable risk. This contrasts with the whether monovision will work for them. It is situation in refractive surgery where most helpful for patients to undergo a trial of surgeons are punctilious in discussing this monovision with contact lenses before the subject. This may create the impression that monovision is sculpted on to their cornea. refractive surgery is riskier than, for example, Figure 8 Nevertheless, the penalty for monovision- cataract surgery when in reality the opposite A damaged cornea flap after LASIK failure is low since it is straightforward to is probably true. (by courtesy of the Gimbel Eye Centre, Calgary, Canada) enhance the patient from under correction Selected LASIK complications, their cause to emmetropia if necessary. and management include the following: topography. It is now believed that such • The flap may be abnormally shaped – thin, a discrepancy arises as much from the Enhancement hingeless, irregular or buttonholed (Figure posterior corneal surface as from the lens The term ‘enhancement’ means performing a 8). This usually results from poor surgical (lenticular astigmatism). Patients with top-up procedure to amend the initial LASIK technique. For example, failure to high ocular residual astigmatism may correction. The ability to amend an initially achieve sufficient suction prior to have poor contrast sensitivity after unsatisfactory ablation is one of the most cutting the flap or allowing an surgery if the cylinder axis of the appealing aspects of modern laser refractive obstruction such as the eyelashes or manifest refraction is sculpted on to an surgery. It is not necessary to recut the surgical drape to get in the way of the anterior corneal surface in which the LASIK flap. Using appropriate cutting blade. This complication is cylinder is orientated completely instrumentation and technique, it is infrequent with modern microkeratomes. differently. There are now sophisticated possible to lift the original flap for many It is often possible to replace the software programs available to guide the months after the procedure. This inevitably inadequate flap in its original surgeon in dealing with this situation, raises the question of whether the flap has orientation, allow it to heal fully which e.g. the ASSORT program written by Dr healed safely. The answer is that it is takes three months and then recut the Noel Alpins. virtually impossible for a patient to flap with no adverse affect on the inadvertently displace the flap except by outcome; Results vigorous rubbing and even then only within • The corneal epithelium occasionally The recovery time from LASIK is usually a month or so of the procedure. The flap is detaches from the flap whilst it is being brief with a high percentage of patients then to all intents and purposes healed but cut, an event followed by the antithesis achieving 6/6 or similar vision the day fortunately, can still be lifted when of the normal LASIK experience, i.e. after surgery. This ‘wow’ factor is in no necessary by the surgeon. Further laser is post-operative pain. One cause of this is small part responsible for the popularity then applied to the stromal bed and the flap the application of too much pre- of LASIK. One of my patients, an oral is replaced and heals in the same way as operative anaesthetic which can weaken surgeon, returned to operating on his previously. Multiple enhancements can be epithelial adherence. The solution is own patients the day after bilateral performed if necessary. The main sympathy, a bandage contact lens and simultaneous LASIK for a 5 dioptre impediments to enhancement are an unpreserved topical lubricants; myopic correction. However, it is understandable reluctance on the part of the • As discussed previously, inadvertent necessary to warn patients that recovery patient to undergo any further surgery and vigorous rubbing of the flap, usually at may not always be so rapid. the fact that only a limited amount of night when the patient is sleeping, can LASIK results are generally excellent corneal stroma can be removed without a displace it up to about a month post- with a high percentage of patients danger of inducing iatrogenic ectasia. operatively. The reader will be reassured achieving close to emmetropia. For Refractive stability in myopic LASIK occurs to learn that this is a very uncommon example, in one series, 83.4% of patients quickly so that enhancement in these event. The patient is immediately aware were within 1 dioptre of emmetropia after patients can be performed as early as one of an unpleasant foreign body sensation. the initial LASIK procedure for myopia month after the initial procedure8. However, The flap is generally easily replaced by ranging from 1 to more than 10 dioptres5. in hyperopes, complete stability can take as the surgeon without untoward affect; Similarly, excellent outcomes are now long as three months to occur so • Dry eye and blepharitis are temporarily expected from hyperopic treatments enhancement should wait until this period worsened by LASIK probably because of following technical improvements in the has passed. the loss of neural supply to the cornea LASIK procedure. For example, about 97% surface occasioned by the slicing action of patients with hyperopia of up to 3 Complications of the microkeratome. Fortunately, neural dioptres were within 1 dioptre of The long list of potential complications regrowth occurs after about three emmetropia following LASIK6. In general, associated with LASIK contrasts sharply with months; there is a strong trend in the published the small percentage of patients who suffer • Haze (scarring) and regression are literature for improved outcomes. This them. This is a tribute to the excellence of unusual after myopic LASIK but change is obvious when comparing data the technology but also serves as a reminder occasionally occur following hyperopic published in 1999 with, for example, of the high level of surgical skill and training corrections. Prevention is better than 1996. This reflects the rapid evolution of necessary to be a successful LASIK surgeon. cure, in this case by avoiding high hardware design (lasers and This is not an activity that can be safely hyperopic corrections; microkeratomes), the software used to performed on an occasional basis by an • Halos around oncoming car headlights at

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night result from a mismatch between pupil References size and the ablation zone. Once again, the problem is easier to avoid than treat, in this 1. Gimbel, H.V. and Levy, S.G. case by advising against surgery when (1998) “Indications, results scotopic pupils are large; Loss of two lines of and complications of LASIK”. best corrected visual acuity occurs in about Current Opinion in 0.9% of recent publications2 but frequently Ophthalmology 9: 3-8. this occurs in circumstances such as a 10 2. Farah, S.G., Azar, D.T., Gurdal, dioptre myope who is 6/6 uncorrected C. and Wong, J. (1998) “Laser following LASIK having been 6/4 in contact in situ keratomilieusis: lenses. Such patients are usually happy to Literature review of a swap marginally decreased acuity for vastly developing technique”. J. enhanced unaided vision. Cataract Refract. Surg. 24: 989-1006. When all is said and done, the most common 3. Gimbel, H.V., Basti, S., Kaye, ‘complication’ is simple under or over correction G.B. and Ferensowicz, M. which can generally be dealt with by (1996) “Experience during the enhancement. learning curve of laser in situ keratomileusis”. J. Cataract Forthcoming developments Refract. Surg. 22: 542-550. The tools used to perform LASIK, both hardware 4. Waring, G.O.I., Carr, J.D., and software, are improving quickly. Stulting, R.D., Thompson, K.P. Improvements on the horizon include and Wiley, W. (1999) microkeratomes which cut with a laser instead of “Prospective randomized a metal blade and so-called customised ablation. comparison of simultaneous The latter refers to an ablation designed to and sequential bilateral LASIK precisely mirror the contours of an individual for the correction of myopia”. patient’s cornea rather than one based on the Ophthalmology. 106: 732-738. manifest refraction. This work has reached an 5. Gimbel, H., Penno, E., van exciting stage of development and will probably Westenbrugge, J., soon be in routine clinical use. For example Ferensowicz, M. and Furlong, Bausch & Lomb recently launched its latest M. (1998) “Incidence and customised laser vision correction procedure, management of intraoperative Zyoptix™, which utilises wavefront technology, and early postoperative and similar systems are under development by complications in 1000 other companies. Customised ablation profiles consecutive LASIK cases”. will improve contrast sensitivity and probably Ophthalmology 105: 1839- ultimately lead to the creation of myopic ablation 1848. profiles that are prolate (rather than oblate as at 6. Argento, C.J. and Cosentino, present) so maintaining normal corneal M.J. (1998) “Laser in situ geometry. keratomilieusis for hyperopia”. J. Cataract Refract. Surg. 24: LASIK and optometrists 1050-1058. Refractive surgery is here to stay although in a 7. Wright, K.W., Guemes, A., country as conservative as the UK, it seems Kapadia, M.S. and Wilson, S.E. unlikely to become as popular as elsewhere. (1999) “Binocular function Optometrists are ideally placed to act as and patient satisfaction after gatekeepers, directing patients who enquire monovision induced by about it to surgeons whose outcomes they know myopic photorefractive to be good. Co-management of the keratectomy”. J. Cataract pre-and post-operative phases is the norm abroad Refract. Surg. 25: 177-182. and will doubtless become so here. Refractive 8. Spadea, L., Bianco, G., Masini, surgery co-management, direct referral of cataract M.C. and Belestrazzi, E. to ophthalmologists, greater involvement with (1999) “Videokeratographic diabetic and glaucoma screening and other changes after lser in situ aspects of primary eyecare will perhaps combine keratomilieusis to correct to create ‘medical optometry’ as an exciting new high myopia”. J. Cataract avenue of optometric practice. Refract. Surg. 25: 1589-1595. About the author Simon G. Levy is Consultant Ophthalmologist at North West London Hospitals NHS Trust. He also practises privately at the BUPA Hospital Bushey and the Garden Hospital, London. He specialises in the anterior eye - cataract, refractive surgery, cornea and external eye disease. His Internet information service for refractive surgery patients is at www.eyesite.org.

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Multiple choice questions - Please note there is only one correct answer LASIK

1. Which is true about the indications a. Corneal topography is essential b. It is difficult to change monovision once for LASIK? b. Corneal pachymetry is only necessary in it has been created a. It has no role in the management of selected cases c. Results are similar to those achieved hyperopia c. Recent contact lens wear does not with contact lenses b. It can treat almost any degree of affect the measurements made d. Monovision cannot be created by LASIK myopia d. Keratoconus is not a contra-indication c. It can treat about 11 dioptres of to LASIK 10. Which of the following are true combined sphere and cylindrical about LASIK enhancement? correction in myopia a. It is necessary to recut the flap d. It can treat up to 11 dioptres of 6. Which of the following b. It is impossible to lift the flap after a combined sphere and cylindrical is false about LASIK? month post-operatively correction for hyperopia a. Blepharitis is likely to be temporarily c. Several enhancements can be performed worsened post-operatively if necessary 2. When comparing LASIK and PRK, b. Dry eye is likely to be temporarily d. It is always possible to perform an which of the following is true? worsened post-operatively enhancement a. PRK is currently performed much more c. The depth of the laser ablation and the frequently then LASIK degree of myopia are not directly 11. Which of the following is false b. LASIK is currently performed much more related to each other about LASIK complications? frequently then PRK d. Patients with high ‘ocular residual a. A high degree of training is required c. PRK causes little post-operative astigmatism’ may have poor contrast to minimise the likelihood of discomfort sensitivity post-operatively complications d. Vision generally takes several weeks to b. The risk of complications is no higher recover after LASIK than in the context of cataract surgery 7. Which of the following is true c. The flap may be abnormally shaped, 3. When comparing LASIK and PRK, about the surgery of LASIK? making it impossible to apply the laser which of the following is false? a. General anaesthesia is preferred ablation a. Regression rarely occurs after myopic b. Topical anaesthesia (eyedrops) is d. There is virtually no chance LASIK preferred of epithelial trauma b. Regression frequently occurs after PRK c. The flap is cut by hand c. Haze is more likely to occur following d. The flap needs to be sutured into place 12. Which of the following is true about LASIK than PRK LASIK complications? d. LASIK is a more sophisticated surgical a. The flap may easily detach up to several technique then PRK 8. Which of the following is false about months following the procedure the post-operative management of b. Halos when driving at night sometimes 4. Which of the following LASIK? occur post-operatively is false about LASIK? a. There is no pain c. Haze (scarring) commonly occurs after a. The ablation is applied directly to the b. Patients may return to work quickly. myopic LASIK corneal epithelium c. Prolonged (up to six months) use of d. Under or over correction b. A flap of tissue is made with a steroid eyedrops is required are very rare events microkeratome d. A combination antibiotic and steroid c. The healing response is less than after drop is used QID for one week An answer return form is included in PRK this issue. It should be completed and d. Laser is not applied to the corneal returned to: CPD Initiatives (RS5), endothelium 9. When considering monovision in the context of LASIK which of the OT, Victoria House, 5. Which of the following is true following is true? 178-180 Fleet Road, Fleet, concerning the pre-operative LASIK a. Monovision generally produces Hampshire, GU13 8DA by June 14. consultation? unsatisfactory results

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