GP Problem Solving
With Dr. Pat Keech and Dr. Ken Maller
Links to Case Studies:
Case 1
By: Dr. Pat Keech
Patient is a white male yoga instructor, age 50, with keratoconus and dry eyes. Recent corneal graft on the left eye is still in recovery. His right eye underwent PKP in 1991 and he has been wearing a bitoric gas permeable lens with good success. Recently, the right lens began popping out several times a day, indicating a refit is in order. The patient uses Restasis bid and Refresh contacts qid.
Presenting right lens parameters:
Boston XO: BC 6.85/7.38 Power -14.50/-17.50 Diameter: 9.0 BVA 20/20-
Refraction: -13.75 –2.25 x 065 VA 20/150
Corneal topography attached, indicating significant oblique astigmatism of the corneal graft with reverse geometry, that is, the central bow tie is significantly flatter than the surrounding bed.
Even though the corneal astigmatism approaches 7 D, I decided to try a stock reverse geometry lens (CRT) to see if good centration and vision was achievable.
The following trial lens was inserted for observation:
- OD: BC 7.70 Power: +050 Diameter 10.50 LZA –35 RZD .575 Paragon CRT in hds 100
- Edge lift at 4:00 was noted, but with over-refraction of –13.00, VA 20/30 was obtained. The lens centered well with good peripheral tear exchange and movement.
The following lens was ordered:
OD: CRT design BC 7.60 Power: -13.00 Diameter 10/50 LZA –35 RZD .575
When the lens was dispensed 8 days later, the over-refraction was +1.00 with VA 20/15-
Therefore, a new lens was ordered, incorporating a power change:
OD: CRT design BC 7.60 -12.25 Diameter 10.5 LZA –35 RZD .575
The final design has been tolerated well for daily wear for two years, despite the edge lift at 4:00. Corrected vision remains 20/20 or better in the right eye.
Case 2
By: Dr. Pat Keech
Patient Judith V, is age 60, and has Type II diabetic with no retinopathy. She has been wearing aspheric simultaneous multifocal gas permeable contact lenses since 2003. Last year she had seen another optometrist due to insurance changes, and he was unable to refit her due to comfort challenges, so she went back to her old contact lenses, even though the vision had deteriorated. She has returned to our office for a refitting.
Presenting lenses:
OD Lifestyle Marquis BXO multifocal BC 7.54 EQ 7.70 Power –2.25, hi add 9.5 Diam
OS Lifestyle Marquis BXO multifocal BC 7.54 EQ 7.70 Power –3.00 hi add 9.5 Diam
Visual acuities: OD 20/25 OS 20/40 at near (modified monovision, OD for distance)
Both lenses were fitting over 1 D flat, with superior nasal positioning
The over-refraction indicated that both eyes were overminussed at least +0.50 D.
The patient also experienced significant spectacle blur. Post-refraction was at least 1.00 D less minus than her refraction previous to fitting in 2003. This is not uncommon with aspheric multifocal fittings, especially if the patient has somewhat low ocular rigidity, which this patient has demonstrated.
Corneal topographic maps are attached. (Please excuse the poor resolution due to low ink.) The central flattening and inferior steepening are not uncommon in long-term rigid contact lens wearers, and most probably are induced by the high riding contacts. The goal in refitting is to correct the over-minused status, improve the visual function and maintain the good comfort.
Although this corneal topography resembles keratoconus, this patient has no signs of the disease. No corneal thinning and no reduction in best corrected visual acuity are present. She does appear to have what I call “low corneal rigidity” in that her corneas are malleable and change shape easily, thus the spectacle blur. But we can use lens designs intended for keratoconus to improve fit and function. You may have noticed that highly aspheric lens designs such as the Rose K lens offer better near vision for your presbyopic keratoconic patients than expected. Also, such a lens should provide better centering, just as it does for similarly shaped KC patients. Therefore, we decided to do a trial fitting with Rose K lenses to see the result.
Trial lenses:
OD 7.40 -2.00 8.7 Rose K Over-refraction –0.75 with VA 20/25+2
OS 7.30 -3.00 8.7 Rose K Over-refraction –1.25 with VA 20-25+3
There was good movement and centration, only slightly superior, but with excessive edge lift, so we ordered steep peripheral curves. N The diameter was also increased to aid in centering the lenses.
Lenses ordered:
OD 7.35 -3.25 9.2 Rose K in BXO with steep PC
OS 7.30 -4.25 9.2 Rose K in BXO with steep PC
When the lenses were dispensed, the distance VA was 20/25 in each eye at distance with 20/20 OU. At near the vision was 20/30 OU. At the two week progress check, the distance visual acuity had improved to 20/20 in each eye, with 20/30 at near. The patient does need OTC readers +1.00 for very fine print in dim light, but does without readers most of the time. The lenses center well with good movement. The refraction after lens removal has returned to her previous levels. And the fluorescein pattern with the lenses in situ shows alignment, not the central bearing pattern previously shown with her former contact lenses.
Case 3
By: Dr. Ken Maller
Background Information
Patient A.S. is a 61 year old female that has a history of hard lens wear of approximately 20 years, followed by gas permeable lens wear for an additional 20 years. The gas permeable lens wear was discontinued when she became intolerant of the lenses approximately 3 years ago. Her gas permeable lens intolerance was due to discomfort and resulted in very reduced wear time. At that time she was fit into soft contact lenses and has worn them for the past 3 years despite the fact that she complained her vision was rather poor. Finally frustrated by the poor vision with the soft lenses she was wearing, she sought another Optometric Physician that elected to refit her into SynergEyes M lenses. She was delighted with her vision as she was now able to see very well at both distance and near but she soon developed wearability problems. Her eyes were becoming irritated as well as she reported extreme difficulties in wearing her glasses due to significant blur upon removal of her SynergEyes M lenses.
She was referred to Ophthalmology for assessment of this irritation episode. The symptoms included difficulty focusing, excessive tearing and a sensation that the eyes were swollen. Lens wear was discontinued and she was prescribed Zylet. This irritation resolved and she resumed wear with the SynergEyes M lenses. Three months later she once again was referred to ophthalmology for excessive irritation, tearing, and decreased vision over the previous four days, worse in the left eye.
Entering acuities with the SynergEyes M lenses were:
OD 20/70- Ph 20/50+2
OS 20/80 Ph 20/40-.
Noteworthy findings from this exam included a diagnosis of mild keratitis OS and a question as to whether or not she has Keratoconus. Topography was done this day and can be seen below.
At the conclusion of this visit with Ophthalmology, she was referred to me to corroborate the diagnosis of Keratoconus as well as refit her to eliminate the recurring keratitis that was likely due to the SynergEyes M lenses. She reported to me eight days later.
Her entering spectacle acuity was:
OD 20/50-
OS 20/80+
The spectacle prescription she was wearing was:
OD –1.50 – 350 x 180 +1.25 Add
OS –0.50 – 1.50 x 180 +1.25 Add
I refracted her that day finding:
OD –4.00 – 1.25 x 090 20/50-
OS –0.25 – 1.00 x 080 20/80+
I performed topography this day also, and that can be seen below.
Although both corneas are clearly irregular, my impression was that the impact of the SynergEyes M lenses were obscuring the true underlying diagnosis. Normally in a situation like this, I would fit a pair of “transition” lenses that would allow the patient to function while also allowing the corneas to rehabilitate and return to their more normal state. Unfortunately for this lady, I was leaving town the next day and would not return to the office for almost 3 weeks. Due to this logistical timing issue, we mutually agreed that the best course of action for us would be for her to discontinue wearing the SynergEyes M lenses for the next four weeks, at which time she would return to my office so that we could better assess her underlying condition as well as refit her into a better contact lens option than the SynergEyes M lenses.
During the 3 week period that I was out of the office, the patient became nervous that perhaps her vision may not ever be correctable and so decided to seek another opinion. She went to a corneal specialist that diagnosed her with Keratoconus and subsequently referred her to a contact lens fitter within his office.
The patient elected not to proceed with the contact lens fitter within the corneal specialist’s office because that fitter indicated that it would be highly unlikely that they would successfully address the patient’s presbyopia with contacts alone. The patient felt that this fitter would not be fully addressing her needs and so she decided to wait for me to return to my office.
The patient returned to my care 4 weeks after our initial encounter. She had not worn the SynergEyes M lenses since that time. She also told me about her diagnosis of Keratoconus from the corneal specialist which now had her very distraught as she had had some time to do some research on the internet about the condition. She did also have a new pair of glasses made from a prescription that she received in the corneal specialists office.
This new spectacle Rx was:
OD –2.50 – 1.75 x 006 +2.25 Add
OS –1.75 – 0.50 x 016 +2.25 Add
Distance acuity with these spectacles:
OD 20/25-
OS 20/25-
Her refraction on this day was now:
OD –2.50 – 2.75 x 002 +2.50 Add
OS –1.75 – 2.25 x 005 +2.50 Add
Distance acuity with this refraction was:
OD 20/20-
OS 20/25+
Near acuity with this refraction was:
OD 20/20-
OS 20/20-
Her topography on this day can be seen below.
Although a somewhat compromised tear film can be seen on the topography, and the inferior cornea is slightly steeper than the superior, these corneas are showing very regular astigmatism (slightly asymmetric) and no sign of Keratoconus. I suspect that given more time with no contact lens wear, along with ocular surface treatment to restore a more normal pre-corneal tear film, and the asymmetry of the astigmatism would approach even greater symmetry. The remainder of the exam was non-contributory.
At the conclusion of my exam, I explained my findings to the patient. After a long discussion of the options that were open to us, I recommended refitting her into gas permeable multifocals. She reminded me again that she was forced to discontinue wearing her gas permeable lenses 3 years earlier due to discomfort and intolerance. Despite her skepticism, I convinced her to at least explore this path that I had recommended.
Fitting Information
Using Wave software, I designed a custom pair of gas permeable multifocals. The parameters of the lenses are as follows:
OD
Material: Optimum Extra
Base Curve: 7.19 +/- 0.17 mm
Diameter: 11.30 mm
Power: -3.69 +/- 1.41 D
Center Thickness: 0.19 mm
Edge Thickness: 0.13 mm
Front Pupil: 3.40 mm
Center Distance design multifocal
OS
Material: Optimum Extra
Base Curve: 7.23 +/- 0.15 mm
Diameter: 11.30 mm
Power: -2.96 +/- 1.24 D
Center Thickness: 0.19 mm
Edge Thickness: 0.13 mm
Front Pupil: 3.40 mm
Center Distance design multifocal
Upon dispensing these lenses, results were as follows:
Monocular Distance Acuity:
OD 20/20-
OS 20/40
Distance Over-Refraction with Trial Lenses:
OD +0.25 20/20
OS +0.75 20/25
Monocular Near Acuity:
OD 20/50
OS 20/50-
Near Over-Refraction with Trial Lenses:
OD +1.25 20/20-
OS +1.50 20/20-
Biomicroscopic Evaluation:
OD Well centered, well aligned, good movement, slightly loose.
OS Positioned slightly nasal, slight excessive inferior edge lift, overall loose.
Plan: Since the lenses were not fitting nor correcting as ideal as I would have liked, I did not dispense this pair to her. I redesigned both lenses. OD slightly tighter, increase (+), decrease pupil size, OS tighten the vertical peripheral area, increase (+), decrease pupil size.
New lens parameters:
OD
Material: Optimum Extra
Base Curve: 7.18 +/- 0.18 mm
Diameter: 11.30 mm
Power: -3.11 +/- 1.79 D
Center Thickness: 0.23 mm
Edge Thickness: 0.13 mm
Front Pupil: 3.20 mm
Center Distance design multifocal
OS
Material: Optimum Extra
Base Curve: 7.20 +/- 0.15 mm
Diameter: 11.30 mm
Power: -1.94 +/- 1.65 D
Center Thickness: 0.23 mm
Edge Thickness: 0.13 mm
Front Pupil: 3.10 mm
Center Distance design multifocal
Upon dispensing these new lenses, results were as follows:
Monocular Distance Acuity:
OD 20/20
OS 20/20-
Distance Over-Refraction with Trial Lenses:
OD Plano 20/20
OS Plano 20/20-
Monocular Near Acuity:
OD 20/20
OS 20/20
Near Over-Refraction with Trial Lenses:
OD Plano 20/20
OS Plano 20/20
Biomicroscopic Evaluation:
OD Well centered, well aligned
OS Well centered, well aligned
Application, removal, and care was reviewed. She was instructed to use Optimum solutions.
Follow-Up
She came back for follow-up nine days later. She reported that her comfort and vision were excellent. Wearing time was 14 – 16 hours per day.
Monocular Distance Acuity:
OD 20/20
OS 20/20
Distance Over-Refraction with Trial Lenses:
OD Plano 20/20
OS Plano 20/20
Monocular Near Acuity:
OD 20/20
OS 20/20
Near Over-Refraction with Trial Lenses:
OD Plano 20/20
OS Plano 20/20
Biomicroscopic Evaluation:
OD Well centered, well aligned, (-) NaFl staining
OS Well centered, well aligned, (-) NaFl staining
Discussion
I believe this case has lessons on several levels. In fact, when I finished the case, I sent a report to the original Optometric Physician that fit her into the SynergEyes M lenses as well as another report to the referring Ophthalmologist, and both doctors were surprised by the “Synergitis” (the term I coined for the corneal redistribution and inflammatory keratitis induced by the SynergEyes lenses). The Ophthalmologist was genuinely surprised by the Keratoconic-like corneal topography that was created by the SynergEyes lenses. I told him that the corneal specialist had also incorrectly diagnosed her with Keratoconus. He responded that he wasn’t really all that surprised. He said that the extent of impact that contact lenses can have on corneas such as in this case, is not part of the general knowledge within ophthalmology, and encouraged me to write up this case for general publication. Another very important point to make is that she had a 20 year history of hard lens wear, 20 years of gas permeable lens wear, and 3 years ago she became intolerant. Despite this history of intolerance, I recommended returning to gas permeable lens wear because upon examination I did not see any specific reason for the previously reported contact lens problem. The patient is doing exceptionally well with both her vision and her comfort and is delighted that I convinced her to explore a return to gas permeable lenses. This was obviously a good choice of treatment for this woman.
Links to Case Studies:
