Links to case 1 (Dr. Robert Maynard)
Case 1
OD/OS Compare Display
Links to case 2 (Dr. Bruce Anderson)
Case 2
PATIENT: JW
DOB: 09/08/1963
System's Analyst
Currently on disability
DX:
Wegeners Granulomatosis
Necrotizing Scleritis
Patient
presented on May 8 on the referral of the ophthalmologist treating her scleritis.
OD had almost no sclera temporal to the temporal limbus with the ciliary body
clearly visible. The MD measured her cornea with 12 diopters of astigmatism.
We could only achieve 8 diopters.
RX:
-1.75-8.00x150 = 20/70-2 Ks: 41.25=49.50x057
-0.50-4.00x103 = 20/25 45.50=42.50x106
Originally, we decided to fit her with piggyback lenses due to a dry eye
problem. We placed a Purevision 8.6 0.75 OD and Focus Night and Day 8.4 0.50
OS.
TRIAL #1
OD
Comfortkone A10 6.70 -6.00 8.5 8.0/4.0
OS
Kone Lens 7.34 7.03 -5.00 8.8 8.50x.3 10.50x.4
Figure 1a (right eye)
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Figure 1b (left eye) [image not available]
SLE: OD
decentered down and was too tight
OS decentered down and temporal and was far too steep
Over
Refraction: OD 2.00-1.75x180 = 20/40-1
OS plano-1.50x101 = 20/20-
TRIAL #2
OD
ComfortKone A10 7.00 -4.00 8.5 8.0/4.0
OS
GBL 7.85 -4.50 11.2 9.00x.5 11.75x.5 8.8
SLE:
OD drops down and splits the pupil
OS up over superior limbus slightly almost wanted to tend nasal
Over
Refraction: OD - -2.50-0.75x135 = 20/60 dbl
OS - +5.00-2.00x092 = 20/20
TRIAL #3
OD
GBL 7.34 -6.00 11.2 9.00x.5 11.75x.3 8.8oz
SLE
large central bubble every time I tried to move bubble, the lens wanted to
slide around and was still too steep
ORIGINAL FIT
OD
8.28/6.89 +1.12 -8.37 10.0 10.20x.5 11.50x.55 8.5x7.5 oval oz 8.5 cap
OS
7.99/7.42 -0.50 3.75 10.0 9.60x.5 10.60x.55 8.5x7.5 oval oz 8.5 cap
Figure 2a (right eye)
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Figure 2b (left eye) [image not available]
We decided to try the lenses without the bandages to begin.
VA = OD
20/50 Over Refraction = +1.75-0.75x025 = 20/30
OS 20/30 +1.00 = 20/20
Both
lenses were centering and moving well, so we decided to let her wear them until
a follow up visit 1 week later, so we could see how she adapted and if we would
need the bandage lenses.
When she
came in for her follow up visit, the VAs and over RX were essentially the same
as when she picked them up.
SLE OD
decentered down and resting on the lower lid
OS centered and moved very well
The
patient stated that the comfort had been fine, so it was decided to forego the
bandage lenses for the time being.
FINAL FIT
OD
8.13/6.78 +1.87 7.62 10.0 10.20x.5 11.50x.55 8.5x7.5 oval oz
OS
7.99/7.42 +0.50 2.75 10.0 9.60x.5 10.60x.55 8.5x7.5 oval oz
Figure 3a (right eye)
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Figure 3b (left eye)
VA OD =
20/25-2 Over Refraction = +0.25 sph
OS 20/25 -0.25 sph
SLE OD
moves well on blink, centers slightly nasal, steep central
- OS moves well
on blink with a slight temporal decentration, steep centrally
The most
recent photos are shown in Figures 4a and 4b.
Figure 4a (right eye)
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Figure 4b (left eye)
The patient was released for 6 weeks and will be re-evaluated at that time.
OD/OS Compare Display (Click to open full-size image)
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Case 2
Case Report: Contact Lens Refitting Post Surgical - Corneal Transplant
PATIENT: 51-year-old Male.
HISTORY: August 23, 2005. Patient reports corneal
transplants to both eyes secondary to keratoconus. Surgery: Right eye, August
of 1997, Left eye, 1984. Patient presents today for contact lens refitting for
his left eye for which he has visual complaints of reduced vision. He is
currently wearing a rigid gas permeable lens in the left eye with a prescription
of:
SGP II
OS 42.50 / -4.50 / 9.2 / 7.8 // .3/8.90
.4/11.25
BC /Power / Dia / OZ // PC
* Analysis of his current contact lens revealed that it was
warped.
ACUITY: With contact lens
OS 20/40
OVER REFRACTION: Over contact lens OS +1.00
-1.75 x 110 20/20 Acuity
SLIT LAMP EVALUATION: Slit lamp evaluation of the
contact lens fit revealed that the lens was fitting superiorly with the upper
edge of the contact lens under the upper lid. The lens was fitting 3+ flat with
a small central bearing region. There was significant lift of the contact lens
from approximately 4:00 to 9:00 in the inferior edge of the contact lens.
Slit lamp evaluation of the eye without the contact lens
revealed a well-healed corneal transplant with a clear central cornea. There
were no sutures still in place. The interface between the host and donor tissue
was smooth; however, it appeared to be somewhat elevated in the inferior region
with slight plateauing.
TOPOGRAPHY: Enclosed. Evaluation of the topography
revealed a fairly flat vertical central region with a flat superior cornea.
There was significant inferior steepening of the cornea from 3:00 to 9:00 which
would correlate nicely with the plateauing as noted under the microscope.
I proceeded with the contact lens fitting using trial
lenses. The trial lens used had a BC of 7.4 with a -3.00 power, which was made
in Reverse Geometry design. The lens prescription was:
OS 7.4 / -3.00 / 9.8 / 7.6 // .7/7.10 .2/8.40
.2/11.25
BC /Power/ Dia / OZ // PC
With over refraction, I was able to improve the vision in
the left eye to 20/20-0 with a -4.75 over refraction. From the
measurement of the trial lens, the initial contact lens ordered was:
INITIAL CONTACT LENS ORDER:
7.40 / -7.50 / 10.0 / 7.8 // .6/7.10 .2/8.50 .3/12.50
BC / Power / Dia / OZ // PC
The initial contact lens was dispensed on 8/29/05 and the
acuity with the new contact lens was 20/20. There was a +0.25 over refraction
with the acuity still 20/20. The lens was fitting fairly central with the
superior edge of the contact lens slightly under the upper lid. The inferior
edge of the lens was fitting flat; however, there was no edge lift off. A
progress visit was scheduled for one week.
At 9/06/05, a follow-up visit was performed. The patient
reported that the lens was comfortable and had no problems wearing it. The
acuity with the contact lens was 20/20. There was +0.50 over refraction with
20/20 acuity and cylinder measured. The contact lens was observed to be fitting
2+ flat centrally and the superior edge of the contact lens was under the upper
lid. The inferior edge revealed a slight lift off at 5:00 to 7:00. At this
point, the new contact lens was ordered to adjust the fit and the power.
CONTACT LENS ORDER:
SGP II / Reverse Geometry
46.12 / -7.50 / 10.0 / 7.8 // .6/7.10 .2/8.50 .3/12.50
BC /Power / Dia / OZ // PC
The new contact lens was dispensed on 9/06/05. The acuity
with the new contact lens was
20/20-0 with a Plano over refraction. The fit
of the contact lens was fitting centrally 1+ flat. There was no inferior lift
off with the edge of the lens in the 5:00 to 7:00 region as noted previously. A
follow-up was scheduled for two to three weeks.
A final follow-up was performed on 9/29/05, at which point,
the patient reported he was able to wear the lens all day comfortably. He was
very happy with the comfort of the lens as well as the vision. Acuity with the
lens was 20/20-0. The over refraction was Plano. The contact lens
again, was fitting slightly flat centrally with the superior edge of the contact
lens under the upper lid, with no significant inferior edge lift off noted. The
patient was released from care and requested to return for annual examination.
DISCUSSION: This contact lens refit relates to the irregular
topography with the flat region superiorly, and in the vertical meridian.
However, the inferior cornea is fairly steep and somewhat proud. This can
frequently be seen with corneal transplants. In many cases a reverse geometry
contact lens design will allow the lens to fit over the curve/drop off of this
proud region in a way to eliminate contact lens lift off. The initial lens that
the patient was wearing did provide good vision; however, the lens has a very
flat fit relative to the overall contours of the eye. Being so flat, this would
create lift-off of the inferior edge of the contact lens. This would over time
create corneal dryness and punctate staining as related to improper tear film.
To alleviate this problem, a reverse geometry lens will allow the contours of
the contact lens to follow closer to the surface of the eye.
The design features that were incorporated in fitting this
patient into a new contact lens are several:
1. A large diameter lens was used which allows better
corneal coverage and allows vaulting of the contact lens over the entire corneal
transplant.
2. To allow for the proud nature of the corneal transplant
a reverse geometry design was used. The amount of reverse geometry that is used
is relative to the overall steepness of the peripheral cornea, how quickly the
cornea steepens and also how uniform it is 360°
around the entire transplant. A reverse geometry curve of 0.6 mm wide was used
as determined from evaluation of the fitting lens that had been placed on the
eye. The amount of the reverse geometry can be adjusted depending on the desired
effect. The best way to evaluate this is through the use of Fluorescein. If a
fitting lens is placed on the eye and evaluated properly, it can be determined
if the reverse curve is creating the desired effect or it needs to be widened or
steepened.
I have available many diagnostic lenses of various designs
that can be placed on the eye to evaluate the overall fit. By placing a lens on
the eye that is close to what is estimated to be a proper fit, which can be
determined with aid from the topography, then a final lens design can be made as
determined from the fluorescein pattern and how the lens sits on the eye.
Figure 1
Links to case 1 (Dr. Robert Maynard)
Case 1
OD/OS Compare Display
Links to case 2 (Dr. Bruce Anderson)
Case 2
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