Central Coast Day Hospital

Inaugural Optometrist Conference

26th February 2012

Anil Arora

Swetha Velpula

Laser Refractive Surgery In General

Current refractive lasers can treat up to 10-11 dioptres spherical equivalent of myopic astigmatism and up to 4.5 to 5.0 dioptres spherical equivalent of hyperopic astigmatism

LASIK far more commonly performed than PRK – less patient discomfort, faster recovery, no corneal haze

Extremely accurate but undercorrections and overcorrections still occur because of variations in healing response between different individuals

Laser Refractive Surgery In General Despite highly sophisticated technology, still need careful

preoperative evaluation.

Corneal topography is essential in all patients

Corneal pachymetry is essential in all patients

Wavefront guided treatments seldom used in routine cases because of high accuracy of current generation machines and nomograms

Keratoconus and pellucid marginal degeneration are absolute contraindications

Careful refraction required. No contact lens wear for 3 days prior to assessment as CL wear can affect refractive measurements.

Screening refraction results by staff rechecked by surgeon at a second visit

LVCCC – Results at one year Retrospective analysis of patients

treated at LVCCC during 2011

114 eyes of 64 patients

50 patients had bilateral laser procedures

14 patients had only one eye treated

106 eyes underwent LASIK – 74 eyes for bilateral emmetropia, 32 eyes for monovision

8 eyes underwent PRK – all for bilateral emmetropia

Zeiss Visumax and MEL 80 lasers

Type of surgery performed 2011

LASIK74 Eyes (65%)

PRK8 Eyes(7%)

Mono Vision32 Eyes(28%)

Type of Surgery

LASIK

PRK

Mono Vision

LVCCC – Other laser procedures performed in 2011 3 other groups of procedures performed that are not

included in this review

LASIK or PRK refractive enhancement following cataract surgery –12 eyes of 10 patients

Phototherapeutic keratectomy (PTK) for calcific band keratopathy – 8 eyes of 6 patients

PTK for recurrent erosion syndrome – 4 eyes of 2 patients

Gender of patients having laser refractive surgery 2011

26 (40%)

38(60%)

Gender

Male Female

Total : 64 Patients

Female

Male

Age distribution of patients having laser refractive surgery 2011

0

20 (31.3% )

18 (28.1%)

18 (28.1%)

8 (12.5%)

0

5

10

15

20

25

30

35

40

45

18-20 21-30 31-40 41-50 51-60

No

. of

Pa

tie

nts

Years

AGE RANGE

LASIK – Post-op unaided VA 1 Month

0

5

10

15

20

25

30

35

6/5 or better 6/6 6/9 6/12 Less than 6/12

No

. O

f E

yes

Unaided Visual Acuity

LASIK : Post- Operative UA VA - 1 Month

20 (27%)

2 (2.7%)

32 (43%)

20 (27%)

PRK (ASLA) – Post-op unaided VA 1 M

6 (75%)

2 (25%)

0

1

2

3

4

5

6

7

6/6 6/9

No

. of

Eye

s

Unaided Visual Acuity

PRK: Post- Operative UA VA- 1 Month

Monovision Useful option in the management of presbyopia

Often results in good patient outcomes with most studies reporting about 70% satisfaction rate with monovision

Results are similar to those obtained with contact lens wear or with lenses in a trial frame so patient can be given a trial of these to assess suitability for monovision

Is a “compromise” – patient education and setting realistic expectations essential during pre-op testing

Can be achieved with LASIK or PRK

“Near” eye can be retreated post-operatively to achieve bilateral emmetropia if patient unhappy with monovision

Monovision 32 eyes received treatment to specifically produce a

monovision result. All had LASIK.

Dominant eye for distance – 18 eyes

Non-dominant eye for near – 14 eyes

12 patients underwent bilateral treatment - mostly hypermetropic presbyopes (9 patients) but also myopic presbyopes (3 patients)

8 patients underwent unilateral treatment 2 emmetropic presbyopes had myopia induced in their non-

dominant eye

6 myopic presbyopes had their dominant myopic eye made emmetropic

Monovision – Unaided dist VA at 1 M

8 (44.5%)

10 (55.5%)

0

2

4

6

8

10

12

6/5 or better 6/6

No

. of

Eye

s

UA Distance VA (1 Month)

MV Distance Eye: Post-op UA VA-1 Month

Monovision – Unaided near VA at 1 M

10 (71.5%)

4 (28.5%)

0

2

4

6

8

10

12

N5 N6

No

. O

f E

yes

UA Near VA (1 Month)

MV Near Eye: Post-op UA VA-1 Month

Results From Singapore National Eye Centre (Uses Visumax Femto)

37,932 eyes of 19,573 patients underwent LASIK from 1998 to 2007.

Uncorrected visual acuity (means without glasses or contact lenses) achieving 20/40 or better has been consistently above 90% since the year 2000, with 72.8% achieving 20/20 or better. More than 93.0% of eyes achieved within +/- 1.00D target in the last four years.

The overall uncorrected visual acuity (UCVA) for Snellen 20/40 or better postoperatively has been consistently above 90% since the year 2000, with a positive trend achieving 98.0% in the year 2007.

Our Results 6/6 or better unaided

Bilateral LASIK – 70% (52/74 eyes) PRK – 75% (6/8 eyes) Monovision (with LASIK) - 100% (18/18 eyes) OVERALL – 76% (76 out of 100 eyes) 6/6 or better unaided

6/9 or better unaided Bilateral LASIK - 97% (72/74 eyes) PRK - 100 % (8/8 eyes) Monovision (with LASIK) – 100%(18/18 eyes) OVERALL – 98% (98 out of 100 eyes) 6/9 or better unaided

Complications The main “complication” in laser refractive surgery is under-

or over-corrections with most centres reporting a retreatment (enhancement) rate of between 1 and 8%(SNEC 6.2%)

This has been our finding also. So far only 2 eyes have had to be retreated giving us an enhancement of just under 2% (2/114). These were both for undercorrections. The treated eyes achieved 6/5 and 6/6 unaided vision after the enhancement

66% of eyes with +/- 0.5D of target refraction

94% of eyes within +/- 1D of target refraction

Retreatments/Enhancements Usually carried out at 3 months to ensure refractive stability. Still

easy to lift the flap for many months (even 1-2 years)after LASIK. However, flap dislocation extremely rare after one month

Flap recut seldom required.

Our results indicate refractive stability after 1 month (little or no change between 1 -3 months). May consider earlier retreatments

More than one retreatment may be required. Has not been our experience so far.

Need to ensure that there is still enough residual corneal tissue for retreatment. Ideally need 300um or more of residual stromal tissue. Retreatment may not be possible if RST too low.

Complications - Intraoperative Incomplete flap – 0

Dislodged flap – 0

Buttonhole – 0

Eccentric flap – 2

Decentred ablation zones – 0

Loose epithelium - 6

Complications - Postoperative Infection – 0

Flap dislocation – 0

Diffuse lamellar keratitis – 0

Epithelial ingrowth – 0

Post-LASIK ectasia – 0 (so far!)

Flap striae - 6 cases – all resolved over 1-2 weeks with the use of corticosteroid eye drops

Interface debris – 8-10 cases of minor interface debris. None visually significant. None requiring a flap lift and cleaning

Dry eye – transient. Only 2 patients with prolonged dry eye symptoms. Using frequent ocular lubricants

Corneal haze – 0 in LASIK patients, transient in 4/8 PRK patients

Conclusion Still a “young” centre with small numbers to date

Excellent results (in terms of percentages) on par with some of the largest refractive centres worldwide

Very low complication rate – again on par with larger and more established centres

An asset to patient treatment on the Central Coast with a facility to treat refractive errors, presbyopia, post-cataract refractive surprises, and also phototherapeutic keratectomy for band keratopathy and recurrent corneal erosion syndrome

QUESTIONSQ1 Which is true about the indications for LASIK?

It has no role in the management of hyperopia

It can treat almost any degree of myopia

It can treat about 11 dioptres of combined sphere and cylindrical correction in myopia

It can treat up to 11 dioptres of combined sphere and cylindrical correction for hyperopia

Q2 Which of the following is true concerning the pre-

operative LASIK consultation?

Corneal topography is essential

Corneal pachymetry is only necessary in selected cases

Recent contact lens wear does not affect the measurements made

Keratoconus is not a contra-indication to LASIK

Q3 When considering monovision in the context of

LASIK which of the following is true?

Monovision generally produces unsatisfactory results

It is difficult to change monovision once it has been created

Results are similar to those achieved with contact lenses

Monovision cannot be created by LASIK

Q4 Which of the following are true about LASIK

enhancement?

It is necessary to recut the flap

It is impossible to lift the flap after a month post-operatively

Several enhancements can be performed if necessary

It is always possible to perform an enhancement

Q5 Which of the following is true about LASIK

complications?

The flap may easily detach up to several months following the procedure

Halos when driving at night sometimes occur post-operatively

Haze (scarring) commonly occurs after myopic LASIK

Under or over correction are very rare events

ANSWERS Q1 - C

Q2 - A

Q3 - C

Q4 - C

Q5 - B