GP Post-Surgical Correction

With Dr. Bruce Anderson and Dr. Shawna Hill

Links to Case Studies:

• Case 1
• Case 2
• Case 3
• Case 4
• Case 5

Case 1

By: Dr. Bruce Anderson

On March 3, 2009, Patient RL, who is a 79-year-old female, presented for a contact lens fitting for her right eye. RL had a history of a corneal transplant in the right eye secondary to Fuch's dystrophy. RL's vision in this eye at distance with her current glasses, was 20/80⁺². She had never worn contact lenses previously. Topography was performed is enclosed below.

Due to the significant central distortion and astigmatism, it was decided to fit her into a rigid lens. With the aid of the information from the topography, I fit her into a Dyna Intralimbal design. The initial trial contact lens placed on her eye had a prescription of:

Dyna Intralimbal
OD 45.00 / -0.87 / 11.2 / 9.4 / STD
BC / Power / Dia / OZ / PC

With the lens in place and over refraction of -0.25, she could see 20/30 at distance. The initial contact lens held position very well, and exhibited approximately 0.5mm movement. There was a slight central touch from the flourscein pattern with the contact lens. The peripheral edge was slightly tight. From this, I ordered an initial contact lens, in the Dyna Intralimbal design:

Dyna Intralimbal / Menicon Z
OD 44.75 / -0.75 / 11.2 / 9.4 / 1+ Flat
BC / Power / Dia / OZ / PC

The initial contact lens was dispensed on March 10, 2009. The acuity at distance with the lens was 20/40+. The contact lens held well on the cornea and decentered slightly nasally. The fit of the lens centrally was 1- flat. The lens was dispensed at this visit with a wearing schedule beginning at two hours the first day and increasing by one hour a day. A follow-up was scheduled for one week.

At the one week follow-up visit, on March 19, 2009, RL stated that she was doing very well. She currently had the lens on the eye for two hours at this visit, and had worn the lens for a maximum of eight hours. The acuity with the contact lens was 20/40⁺². Over refraction was variable between Plano and +0.50. The contact lens was holding well centrally with a slight nasal decentration and was moving approximately 1/4 mm. There was no significant corneal staining or irritation secondary to the wearing of the lens.

The final follow-up visit was provided on April 2, 2009. At this visit, she stated that she was doing extremely well and was now wearing the lens all day. The acuity with the lens was 20/30-1, over refraction was variable at +0.25 to Plano. The lens was holding centrally very well, again, with a slight nasal decentration. It was moving approximately 1/4 to 1/2 mm movement. Upon removal of the lens, there was no significant corneal staining or irritation. The final assessment is that she was doing very well and the fit was stable. She was discharged for one year with follow-up with her cornea doctor back north in six months (she was a seasonal resident of Florida).

DISCUSSION:
The reason for choosing this patient for the case report is there are many interesting factors that need to be evaluated when fitting this type of patient.

1. She has a corneal transplant and we need to ensure that the lens does not cause any irritation or problems with the transplant.
2. She has an extremely high amount of astigmatism as measured with the topography, measured at approximately 15.00 D.
3. She has no history of previous lens wear and the ability to tolerate wearing a rigid lens.

In an attempt to correct this astigmatism, one needs to look at the topography and evaluate the condition of the eye and determine what lens design may work best. With evaluation of the topography, it is noted that the astigmatism is located more centrally than peripherally. The astigmatism is located mainly within the graft region. However, there is a nasal drop-off. From this I would expect the lens to shift nasally. By using a large diameter lens, I was able to vault over the central cornea and hold to the peripheral cornea to keep the lens in place. This would also make the lens more comfortable and easier to adapt to wearing. Also from the topography, there is a flatter region at approximately 180° on the cornea. I had concerns that the lens would bear in this area and cause irritation Because of the drop-off nasally and flat region temporally, my initial contact lens used for evaluating the fit was based on the flatter end of the curvature spectrum based on the corneal curvature. The sim Ks were 40.07D/55.57D @ 108°. With this drop-off nasally, a slightly steeper lens could vault over some of these areas and hug the peripheral cornea. The initial trial lens had a base curve of 45.00D and 11.2 diameter. The trial lens fit very well on the eye, however, was slightly tight, and thus, this necessitated the use of a slightly flatter peripheral curve and slightly flatter base curve. Once the contact lens was worn, the lens was decentering slightly nasally. This is due to the steeper region nasally, which allows the lens to slide in the nasal direction. There was slight bearing of the peripheral curve at the 180° flat region; however, this did not prove to be a problem during the wearing of the lens. This was evaluated during each follow-up visit. Fortunately, even though RL did not have a history of wearing contact lenses previously, she adapted to the lens quickly. She did extremely well with the wearing of the lens and was very determined to be successful. She was discharged from immediate follow-up and was scheduled to return in one year.

Other things for discussion about the fit of this lens is the use of a large diameter. Using larger diameter lenses such as this, you can vault over the central cornea. Many times, you may be able to ignore the measured astigmatism in the central region even if it appears to be significant. Look at the topography of the peripheral cornea and determine how far the toricity extends. If the astigmatism is central, a large diameter spherical lens may be the best fit choice. The peripheral curves and edge of lens are used to stabilize and hold the lens in place. Other things to be considered are the material used. With corneal transplants, you do not want to cause irritation to the eye due to lack of oxygen. I prefer to use the highest DK material available with any particular design. The design must be stable with any material and not flex. My favorite materials include Menicon Z and Boston XO2.

The final fitting pearls that may be taken from fitting this cornea:

1. Use topography to evaluate corneal astigmatism and irregularity and realize that many times, the astigmatism that is measured is only central and not peripheral. If this is the case a large diameter lens will usually work well
2. Think large. The larger diameter lenses hold more stably on the eyes, keep their position better, move less and cause less lens awareness. Large diameter lens will fit up under the upper lid and create a more comfortable fit.
3. Use high permeable and stable materials to prevent a hypoxic situation that could aggravate a corneal transplant.

Case 2

By: Dr. Bruce Anderson

Patient DW was initially seen on January 15, 2008 as a referral for a contact lens fitting. DW had a history of keratoconus in both eyes and subsequently had a corneal transplant in the left eye. He presented for a lens refitting for his left eye. He was presently wearing a rigid lens over a piggy-back soft contact lens and wanted to be fitted into a better lens. His vision with his current contact lens at distance was 20/30 in the left eye.

Slit lamp evaluation of the left eye with the contact lenses removed revealed a well healed and clear corneal transplant in the left eye. The central cornea was clear with a trace of punctate staining. There were no remaining sutures in place. Topography was performed and the results are enclosed below.

DW reported trying rigid contact lenses previously without a soft lens, but was unsuccessful and could not wear the rigid lens comfortably. He was hoping for a more comfortable lens that was not a piggy-back system. Because of his history, I decided to fit him into the SynergEyes hybrid lens. The initial fitting contact lens placed on the left eye had a prescription of:

SynergEyes PS
OS 7.6 / Plano / 8.6 / L 2
BC / Power / SC / Lift

I used high molecular fluorescein to evaluate the fit with the lens in place. The lens centered well and revealed slight pooling paracentrally. There was a light lens touch over the central cornea. The lens exhibited approximately 1/8 mm movement after 10-15 minutes of wear. There was an over refraction of +0.25 with the vision corrected to 20/20. The contact lens ordered for the left eye was:

SynergEyes PS
OS 7.6 / +0.25 / 8.6 / L 2
BC / Power / SC / Lift

The contact lens was dispensed on January 3, 2008. The fit of the left lens revealed that it was centering properly. It was slightly tight with approximately 1/8 mm movement. There was a bubble present at approximately 11:00 close to the limbus. The acuity was 20/20 with a Plano over refraction. The lens was dispensed at this visit and a follow-up visit was scheduled for one week. A wearing schedule was given of two hours the first day, increasing by an hour each day.

At the one week follow-up visit on February 26, 2008, he stated that he was wearing the lens approximately 10 hours. The acuity was 20/20. Over refraction was +0.25. The lens was centering well with approximately 1/8 mm movement. With the contact lens removed, there was no significant corneal staining or irritation. Further follow-up was provided on February 19, 2008. At this visit, he stated that he was still doing well. The acuity with the contact lens was 20/25+. Over refraction was Plano. The lens was moving approximately 1/8 mm. Upon removal of the contact lens, there was a trace of central punctuate staining. I scheduled one further follow-up for approximately three weeks. On March 7, 2008, he was evaluated again. He stated he was doing very well with the contact lens. The wearing time was all day. The acuity was 20/20 with a Plano over refraction. The lens was centering well with approximately 1/8 mm or less of movement. There was no significant corneal staining upon removal of the contact lens. He was released from care at this point and requested that he return in one year.

However, DW was seen on May 28, 2008 for an emergency with acute red eyes in both eyes. DW's profession is a fire fighter, and stated that he had recently fought a major fire with excessive smoke. Since the fire he had been having significant redness and irritation in both eyes. Evaluation of the contact lens in the left eye revealed that it was fitting well and the acuity was 20/25. There was 2+ circumlimbal injection. There was a trace of microcysts 360° at the limbus. The central cornea was clear, however, there was slight punctuate staining. I placed him on Tobradex ophthalmic solution, 1 drop both eyes every two hours for 48 hours and then q.i.d. until return. I asked him to return in one week. At the follow-up visit on June 11, 2008, he said that he was doing very well and was currently back to wearing the contact lens. He stated that he had not had any further problems, and his eyes had cleared quickly after starting the medication. I did provide warnings about wearing the lenses in noxious environments and the need to remove the lenses as soon as possible in these situations. No further follow-up was scheduled.

DISCUSSION:
The choice for fitting the SynergEyes lens was made because of DW's previous intolerance to rigid lenses. He was wearing a piggy-back system, but he was not pleased having to wear two lenses. The initial trial Synergeyes lens that was chosen to be placed on the eye was based on the topography readings. The central cornea readings for the left eye were 44.71/ 48.50 @ 127. There was also a certain amount of plateauing of the graft. This configuration will usually do well with a reverse geometry design. The initial base curve of 7.6 mm was based on approximating the flatter meridian. The Lift 2 chosen, in that it was in the middle of the available lifts. If lift adjustments needed to be made, the lift could then be increased or decreased as needed. As it turns out, the initial lens did fit well and this parameter was ordered based on the initial evaluation of the fit and flourscein pattern. If it is found that the lens was bearing too heavy on the cornea, then the lift could be changed or the base curve could be steepened to pull it away from the cornea. The fit needs to be followed over several weeks to be sure it is stable and the cornea is not being compromised. Frequently, this lens will tighten on the eye over time. Any changes in the fit from expected should be made with a change in the lens parameters to resolve any problems. Follow up visits should be made over many weeks to several months to ensure the fit is stable. Always use flourscein to evaluate for localized corneal irritation, so the fit can be adjusted to eliminate these potential problem spots. Pay close attention to the junction portion of the lens to ensure that it does not bear too heavy on the cornea. If the touch in this region is too heavy, this will frequently cause irritation. If so, then the fit needs to be adjusted.

Also, there were concerns about the red eye reaction that had occurred after the smoke exposure. Working in an irritating environment and wearing contact lenses is always a concern. Precautions are taken in his work as a fire fighter, but excessive smoke exposure alone (even if contact lenses were not worn) can be a significant problem. Recommendations were made to keep the eyes lubricated as much as possible during fire work. The contacts should be removed as soon as possible after extreme exposure to smoke and other irritants. The lenses should be thoroughly cleaned and disinfected after such exposure.

When fitting a corneal transplant, special care is needed to prevent any hypoxic situation. Chronic irritation and edema could lead to a corneal rejection. Always remove the lens at each visit. Use flourscein to check for any areas of chronic corneal irritation. Check for microcysts, especially at the limbus to look for signs of chronic hypoxia. If changes are noted then the fit needs to be questioned.

DW was seen approximately one year later. At this visit, he was doing well. The vision and the fit were stable and no changes were made.

Case 3

By: Dr. Shawna Hill

Background: 36-year-old female with a long-standing diagnosis of keratoconus and s/p Intacs OS (2005) was referred to the office with a decrease in GP comfort and vision in her "better" eye OD in the past few months. Not wearing GP OS (softperm tore)

Refraction:
OD -12.00+1.75x060 (20/40+2)
OS -18.50+6.00x095 (20/60+2)

Keratometry (Auto K)
OD 52.00/54.50@065
OS 54.50/59.62@107

Plan: Intacs OD and GP fit OS

Pentacam OS

Diagnostic fitting in office
Rose K (Blanchard Lab)
Boston ES with + lenticular

VA c GP OS 20/40+2             CL OR -0.50 (NI)

SLE: Interpalpebral fit, centered and good movement. 3 point touch. Inferior edge lift

Plan: Re-evaluate in 3 weeks

3 weeks later:
VA c GP OS 20/30+ (Vision normally improves from original dispense)

CL OR plano DS

SLE: Good, even fl pattern. Centered and good movement. 3 point touch. Inferior edge lift without staining.

PHOTO OS

Plan: Add ACT grade #2
Asymmetric corneal technology is for the asymmetric keratoconic cornea (steeper inferiorly causing GP edge lift). ACT is quadrant specific and allows the steepening of the inferior quadrant only. Available in 3 grades.
ACT grade #1 for slight pooling stand-off to ACT grade #3 for severe edge stand-off

PHOTO OS after ACT grade#2

Pearl: If GP is rubbing on inferior Intacs segment, ACT can be used to steepen inferior lens. By doing this, edge lift is reduced and it causes greater space mid-peripherally as evidence by the small bubbles.

3 weeks after INTACS OD: Note apical clearance
Unknown GP parameters—was referred from another office

Plan: Re-fit GP OD 3 months s/p Intacs OD
Refraction OD: -6.75+3.00x057 (20/40)
        Much less myopia after bi-segment Intacs!

Keratometry OD: 49.12/51.75@075

Rose K (Blanchard Lab) Boston ES material

VA c GP OD 20/25 with plano OR

Central SPK due to previous apical clearance lens-educated patient that it will resolve with the new fit

Case 4

By: Dr. Shawna Hill

Background: 25 year old male s/p Intacs (OD 5/07 and OS 5/08). Severe keratoconus OU (OS progressed rapidly in 2008). Possible refractive amblyopia OS due to hyperopia. (Intacs causes a hyperopic shift)

Refraction (7/08 s/p Intacs OU)
OD -7.50+4.75x150 (20/400)
OS +5.25+0.50x140 (20/50)

Keratometry
OD 56.2/60.9@099 (Pentacam-auto K unable)
OS 47.12/53.25@094

Current GP parameters (note OS is the GP parameters BEFORE Intacs OS) Boston XO

CL OR
OD +0.25 (20/30+3)
OS +3.50 (20/25+3)

SLE OS c +4.00 Ciba Night 8.4: SCL in place with good movement; GP Pooling centrally with moving bubble.

Plan: Build up wearing time OS-limit to 8 hours. Re-evaluate in 4 weeks

Axial Topography 8/08

Re-fit OS
Flattened GP by ~ 2D
No longer needed std flat PC due to BC changes

GP disp OS 9/08

Vcc OS: 20/50+
CLOR OS: +1.00 (20/30)
(This can be frustrating as the s/p Intacs patients can shift during the lens fitting process. This is why we wait a minimum of 3 months before re-fitting unless absolutely necessary.)

SLE

Plan: Re-order with new power, all other parameters the same

Update: Last follow-up exam 3/09
Vcc 20/30+2 OD, OS with plano CLOR

Patient is doing well.

Case 5

By: Dr. Shawna Hill

Background: 44 year old male with PMD OS. Intacs OS 8/06 with subsequent removal 6/07 due to gaping incision wound.

Refraction OS: -4.75+6.00x025 (20/30-2)

The flat/steep option from Lens Dynamics (Wheat Ridge, CO) did not adequately resolve the PMD pattern in this case of peripheral seal-off at 11-12 o'clock, edge lift at 2 o'clock and bearing at 5 o'clock.

Next option: Quad sym design!

Note the much steeper base curvature chosen for the inferior quadrant.

SLE Photo: fitting and initial dispense of this lens. FYI- Use piggyback OS with Ciba Night and Day (+0.50, 8.4 BC) to prevent discomfort.

Note the better fitting relationship in after a few weeks of wear.

Gaping incision wound has re-epithelialized but has excavated appearance.

It is important to re-evaluate after two weeks of continuous wear, and do not change parameters too quickly.

Links to Case Studies:

• Go to Case 1
• Go to Case 2
• Go to Case 3
• Go to Case 4
• Go to Case 5
• Back to top