By Dr. Robert Maynard
Currently on disability
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:||-1.75-8.00×150 = 20/70-2||Ks:||41.25=49.50×057|
|-0.50-4.00×103 = 20/25||45.50=42.50×106|
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.
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)
Figure 1b (left eye) [image not available]
OD: decentered down and was too tight
OS: decentered down and temporal and was far too steep
OD: –2.00-1.75×180 = 20/40-1
OS: plano-1.50×101 = 20/20-
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
OD: drops down and splits the pupil
OS: up over superior limbus slightly – almost wanted to tend nasal
OD: -2.50-0.75×135 = 20/60 dbl
OS: +5.00-2.00×092 = 20/20
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
OD: 8.28/6.89 +1.12 -8.37 10.0 10.20x.5 11.50x.55 8.5×7.5 oval oz 8.5 cap
OS: 7.99/7.42 -0.50 –3.75 10.0 9.60x.5 10.60x.55 8.5×7.5 oval oz 8.5 cap
Figure 2a (right eye)
Figure 2b (left eye) [image not available]
We decided to try the lenses without the bandages to begin.
|VA:||OD 20/50||Over Refraction:||+1.75-0.75×025 = 20/30|
|OS 20/3||+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 VA’s and over RX were essentially the same as when she picked them up.
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.
OD: 8.13/6.78 +1.87 –7.62 10.0 10.20x.5 11.50x.55 8.5×7.5 oval oz
OS: 7.99/7.42 +0.50 –2.75 10.0 9.60x.5 10.60x.55 8.5×7.5 oval oz
Figure 3a (right eye)
Figure 3b (left eye)
|VA:||OD 20/25-2||Over Refraction:||+0.25 sph|
|OS 20/25||-0.25 sph|
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)
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)
Case 2: Contact Lens Refitting Post Surgical – Corneal Transplant
By Dr. Bruce Anderson
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:
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
Over Refraction: Over contact lens
OS +1.00 -1.75 x 110 20/20 Acuity
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 Orders:
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.
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:
- A large diameter lens was used which allows better corneal coverage and allows vaulting of the contact lens over the entire corneal transplant.
- 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.