1
Development of Unilateral Corneal Ectasia After
PRK with Ipsilateral Preoperative Forme Fruste
KeratoconusJacob Reznik, MD¹ James J. Salz,
MD² Alena Klimava, MS³.1. Wilmer
Ophthalmological Institute, Johns Hopkins
University, Baltimore, MD, USA2. Laser Vision
Medical Associates, Cedars Sinai Medical Center,
Los Angeles, CA, USA3. The Johns Hopkins
University School of Medicine, Baltimore, MD,
USACorresponding authorJacob Reznik,
MDWilmer Ophthalmological InstituteJohns
Hopkins University600 N. Wolfe Street, Wilmer
B27Baltimore, MD 21287E-mail
jreznik1_at_jhmi.eduPhone [phone]Fax
[phone]The authors have no proprietary
interest in the materials presented herein.
2
Abstract Purpose To describe clinical and
topographic features of a prominent keratectasia
after photorefractive keratectomy (PRK) in a
patient with abnormal preoperative
topography. Methods A 25-year-old man underwent
bilateral uneventful PRK for moderate myopia of -
5.75 - 1.75 x 95 OD and - 7.50 -1.25 x 80 OS with
BSCVA 20/25 OU. Preoperative corneal pachymetry
was 500 µm OD and 460 µm OS. The total calculated
ablation depth was 70 µm in the right eye and 100
µm in the left eye. Preoperative corneal
topography revealed forme fruste keratoconus
(FFK) OD with I-S ratio of 4. Results 5 years
postoperatively, the patient developed unilateral
inferior keratectasia OD with refraction of
0.50 - 5.50 x 90 with BSCVA of 20/100 and central
pachymetry of 481 µm with inferior pachymetry of
374 µm. Conclusion This case reports adds to
the growing body of evidence in the ophthalmic
literature suggesting that patients with
preoperative FFK or early keratoconus may develop
clinically-significant progression of corneal
ectaisa after PRK.
3
Case reportA 25-year-old man was evaluated
for refractive surgery to correct moderate
myopia. The patient deniedprevious contact lens
wear and his ocular history was otherwise
unremarkable. No previous history ofchronic eye
rubbing, other trauma, or atopy was reported. No
family history of corneal ectasia wasreported.
No signs of clinical keratoconus were seen on
slit-lamp biomicroscopy. Dilated
funduscopicexamination was within normal limits.
BSCVA was 20/25 in both eyes with a refraction
of - 5.75 - 1.75 x 95 OD and - 7.50 - 1.25 x 80
OS. Preoperative central corneal pachymetry was
500 µm OD and 460 µm OS.Keratometry readings
were 42.50/42.25 x 90 OD and 43.25/44.00 x 90 OS
with no distortion of thekeratometer mires
OU.No clinical signs of keratoconus were
observed with slit-lamp biomicroscopy in both
eyes. Cornealtopography (Optikon 2000) was
normal OS and abnormal OD with obvious inferior
steepening and I-Sratio of 4. (Figure 1). The
abnormal topography was discussed with the
patient. He was informed that laser in situ
keratomileusis (LASIK) was absolutely
contraindicated secondary to abnormal
topographicfindings. He was informed that if he
agreed to PRK this might accelerate the
progression of keratectasiaand if this did in
fact happen, he would most likely require a hard
contact lens and possibly even apenetrating
keratoplasty.On 4/1/98, patient received -6.86
-0.75 X 180 excimer laser correction with the
Visx Star laser (VISXInc., Santa Clara,
California, USA) with ablation zone 6.0 x 5.7 mm
for ellipse and 5.5 mm for sphereOS 303 pulses
were administered. The fellow eye was similarly
treated on 5/27/98 with correction of -4.71
-2.33 X 90 ablation zone of 6.0 mm x 4.9 mm 435
pulses were administered. The total
calculatedablation depth was 70 µm in the right
eye and 100 µm in the left eye.
4

• The early postoperative course was uneventful. 6
  weeks after the procedure, UCVA was 20/20 OU, and
• BSCVA OD was 20/15 (plano -0.25 X 35). Slit-lamp
  biomicroscopy was normal OU.
• At 5 years follow up UCVA was CF at 6 feet OD and
  20/40 OS. BSCVA was 20/25 OD with refraction
• of 0.50 -5.50 x 90 and 20/20 with refraction of
  -1.00 sphere OS. Corneal pachymetry OD was 481 µm
• centrally and 374 µm inferiorly. With
  preoperative pachymetry of 500 µm OD, we thought
  the
• postoperative values might have been related to a
  combination of corneal epithelial hyperplasia and
  new
• collagen deposition. Pachymetry of the fellow eye
  was 450 µm centrally and 450 µm inferiorly.
• Corneal topography (Zeiss Hymphrey Systems)
  showed marked inferior steepening OD and was
  normal
• topography in the fellow eye. (Figure 2) The
  patient underwent Intacs (Addition Technology,
  Inc.)
• insertion with IntraLase femtosecond laser
  (IntraLase Corp.) channels OD in 01/2005.
• Most recent follow up in 04/06 revealed UCVA CF
  at 6 feet OD. BSCVA was 20/70 with - 3.50 - 2.25
  x 105.
• The fellow eye remained stable both
  topographically and clinically. (Figure 2)
• Patient was referred for SynergEyes (SynergEyes
  Inc., Carlsbad, CA) contact lens fit. (Figure 3)
  SynergEyes is a
• hybrid contact lens made of a rigid gas permeable
  (RGP) center fused to a soft, hydrophilic outer
  skirt. This
• design is thought to provide vision correction
  through the central RGP portion of the lens
  combined with a

5

• Discussion
• Keratectasia is a known major complication of
  LASIK. To date, over 100 cases have been reported
  in
• refractive surgery literature (1). Several
  preoperative risk factors have been proposed for
  keratectasia after
• LASIK, such as high myopia, forme fruste
  keratoconus (FFK), and low residual stromal bed,
  but cases
• with mild myopia, normal topography, and residual
  stromal bed gt300 µm also may develop ectasia.
  (2,3)
• Keratectasia is also one of the most difficult
  post-LASIK complications to manage current
  options
• include RGP contact lenses, intracorneal rings,
  phakic toric IOLs and lamellar or penetrating
  keratoplasty
• (4,5,6).
• Even though the upper limit of myopia suitable
  for treatment by LASIK has been arbitrarily set
  as -12.0,
• keratectasia cases after LASIK was noted in cases
  treated for much lower degrees of myopia, from
  4.0
• to 7.0 D (7). Inferior corneal steepening was
  noted in some of these cases pre-operatively. In
  the
• absence of refractive instability or
  biomicroscopic features of keratoconus these
  corneal changes have
• been termed forme fruste keratoconus (FFK) (8).
  There are a few case reports indicating good
  long-term
• refractive outcomes and corneal stability after
  PRK in such cases as compared to LASIK (9,10).
  One
• study of a corneal forward shift after PRK using
  a scanning-slit corneal topography found that
  these
• changes usually stabilize 6 months after surgery
  (11). A more recent case report described a
  patient with
• thin central corneas (485 microns in the right
  eye and 500 microns in the left eye) and corneal
  topography

6

• Discussion (continued)
• Our patient had a clear preoperative FFK in the
  right eye and normal topography in the left eye.
  His other
• risk factors included BSCVA of less than 20/20
  and relatively thin corneas. He elected to
  proceed with
• bilateral PRK and had developed progressive
  corneal changes consistent with clinical
  keratoconus in the
• right eye. The left eye has remained stable over
  the period of 7 years in regards to visual
  acuity, corneal
• topography and biomicroscopic findings. The
  question to ask here is would this patient have
  developed
• progression of FFK in the right eye without PRK?
  Previous studies have clearly demonstrated
• spontaneous progression of FFK into clinical
  keratoconus (13). Our patient has developed
  progressive
• unilateral corneal changes after PRK. His
  refraction has been stable in that eye for
  several years preoperatively.
• It is not unreasonable to suggest that post-PRK
  biomechanical corneal weakening had
• accelerated progression of unilateral FFK to
  clinical keratoconus. A recent longitudinal study
  of
• keratoconus patients concluded that around 50 of
  clinically normal fellow eyes will progress to
• keratoconus in 16 years. (14) It is also not
  unreasonable to theorize that out patient may
  still develop
• clinical keratoconus in the fellow eye in the
  future.

7
Discussion (continued) We conclude
that the issue of PRK safety over LASIK for
patients with FFK and thin, irregular
corneas needs to be studied further before any
recommendations of its preference is universally
accepted. In addition, a careful preoperative
discussion, clinical evaluation and informed
consent are of a paramount importance for
patients with preoperative risk factors who
desire refractive surgery, either LASIK or PRK.
8
(No Transcript)
9
(No Transcript)
10
Figure 3
11
Figure 4
Figure 5
12

• References
• 1. Lifshitz T, MD Levy J, MD Klemperer I, MD
  Levinger S, MD. Late Bilateral Keratectasia After
• LASIK in a Low Myopic Patient.J Refract Surg.
  200521494-496
• 2. Randleman JB, Russell B, Ward MA, Thompson KP,
  Stulting RD. Risk factors and prognosis for
• corneal ectasia after LASIK. Ophthalmology.
  2003110267-275.
• 3. Binder PS. Ectasia after laser in situ
  keratomileusis. J Cataract Refract Surg.
  2003292419-2429.
• 4. Eggink FAGJ, Houdijn Beekhuis WH. Contact lens
  fitting in a patient with keratectasia after
  laser in
• situ keratomileusis. J Cataract Refract Surg.
  2001271119-1123.
• 5. Geggel HS, Talley AR. Delayed onset
  keratectasia following laser in situ
  keratomileusis. J Cataract
• Refract Surg. 199925582-586
• 6. Siganos CS, Kymionis GD, Astyrakakis N,
  Pallikaris IG. Management of post-LASIK Corneal
  Ectasia
• with INTACS. J Refract Surg. 20021843-46
• 7. Amoils SP, Deist MB, Gous P, Amoils PM.
  Iatrogenic keratectasia after laser in situ
  keratomileusis for
• less than -4.0 to -7.0 diopters of myopia. J
  Cataract Refract Surg. 2000 26967977
• 8. Seiler T, Quurke AW. Iatrogenic keratectasia
  after LASIK in a case of forme fruste
  keratoconus.
• J Cataract Refract Surg. 1998 2410071009
• 9. Sun R, Gimbel HV, Kaye GB. Photorefractive
  keratectomy in keratoconus suspects. J Cataract
  Refract