Links to Case Studies:

Case 1

SR 28yowm with 10 year Hx of Keratoconus. Low Cone with history of RGP intolerance.

Fit with Macro lenses on 6/17/2003. OD 6.89/7.50/-10.00 OS 7.18/750/-10.00 VA 20/30+20 20/25-2 Lenses centered well, very comfortable.

From 2003 to 2007 multiple bouts of acute tight lenses episodes OU, Cornea Edema, SPK, Iritis. Responded well to TobraDex, clean lenses, open PCs.

Over time. developed marked Neovascularization 360, OU, diffuse scaring, reduced VA.

Seen on 3/6/2007 VA 20/50, 20/50 Eyes Quiet, lens fitting reasonably well. Elected to re-fit with Reverse Geometry GPs.

Used ABB's custom PMD lens
OD 6.89/-11.50/10.0/6.6/    6.70/.35    8.80/.9    10.5/.45
OS 7.18/-10.00/10.0/6.6/    6.95/.35    9.00/.9    10.70/.45

3/16/2007 Doing well wit new design VA OD 20/25, OS 20/25-1 Generous movement, Cornea clearer, Neo quiet.

4/13/2007 Comfortable with new design VA OD 20/25, OS 20/25 Lenses move and center slightly low but much better than standard designs. Cornea without edema Neo regressing.

Case 2

JT 69yowf Long standing Hx of Keratoconus fit with SoperCones in the 1980s, SoftPerms in the 1990s.

Refit with Marcro Elite Cone Lenses in 2003:

OD 5.81/7.03/ -6.50 VA 20/60 - intermittent bubbles good comfort

OS 5.81/7.03/ -11.00 VA 20/100 unstable with giant bubble minimal acceptable candidate for PK

OS S/P PK-Cat/IOL 1/18/2005.

Multiple bouts of graft rejection OS and irregular cyl.

Pat elected to defer PK OD. Lost Macro OD and not able to duplicate with So2Clear design.

Refit with Reverse Geometry ABB eCorneal design
OD 6.62/-8.50/10.0/6.2    6.37/.3    7.62/1.4    9.7/.2

Lens unstable at dispense with edge standoff and ejection.

Apply B&L PureVision 8.6/+0.75 with same eCorneal as piggy back.

Stable result with optics of eCorneal well centered over pupil 20/25 VA.

Case 3

KERATOCONUS CONTACT LENS FITTING

CASE REPORT: Right and Left Eye

PATIENT: 29-year-old Male

HISTORY: This patient presented for a contact lens fitting on January 29, 2007 for keratoconus. He stated that previously, he had been attempted to be fit into contact lenses and could not find a comfortable lens in the right eye; the left eye was never able to be fit. His vision with his current glasses was 20/70 in the right eye and count fingers at 3 ft. in the left eye.

SLIT LAMP EVALUATION: Under the slit lamp, the right eye revealed slight corneal thinning but no other obvious changes. The left eye had 3+ corneal thinning with 2+ scarring and very obvious Fleischer’s Ring.

TOPOGRAPHY: Enclosed.

DIAGNOSTIC TRIAL LENS: With the use of trial lenses, I proceeded with the contact lens fitting. The initial trial lens for the right eye had a prescription of:

OD   44.75 / -3.00 / 8.6 / .5/9.00 .2/12.20      Standard fitting lens
        BC   / Power/ Dia /      PC

With this trial contact lens in place, the flourscein pattern of the lens was fitting slightly flat and positioned centrally. The edges of the lens were tight. With an over refraction of +0.75, the vision was 20/20.

For the left eye, a fitting lens was used with a prescription of:

OS   60.00 / -8.00 / 8.6 / 6.0 / .3/6.22 .3/7.42 .3/9.22 .4/11.22      Maguire Cone Design
        BC   /Power / Dia / OZ/      PC

During the fitting process for the left, the contact lens would not stay on the eye no longer than a few seconds. Once placed on the eye, upon the first blink, it would pop out of the eye. I was able to position the lens on long enough to see what the contours and the fluorscein pattern of the the lens was. It was observed that the lens was fitting extremely flat centrally, with significant edge lift off. With the aid of topography, and the parameters of the fitting lens as a guideline, the initial contact lenses ordered were:

CONTACT LENS ORDERED:
        Lenticular / Boston XO
OD   44.75 / -2.25 / 9.8 / 7.8 / .4/9.00 .3/11.00 .3/13.00
OS   64.50 / -22.00 / 8.6 / 6.0 / .3/6.10 .3/7.40 .3/9.25 .4/11.50
        BC   /Power/ Dia / OZ /      PC

The contact lenses were dispensed on February 12, 2007. The vision in the right eye was 20/20 and the left eye was 20/30-. With over refraction, the right eye was Plano with 20/20 acuity and the left eye was -0.25 with 20/30 acuity. The right contact lens was centering well with a slight upper lid attachment. The left lens was fitting inferiorly and had 2+ flat edges with a 1+ flat central region. The left lens, upon a forced blink would pop out of the eye. So a second lens was ordered for the left eye with a prescription of:

        Lenticular / Boston XO
OS   66.25 / -24.00 / 8.4 / 6.0 / .3/6.05 .3/7.20 .3/8.40 .3/10.00
        BC   /Power / Dia /OZ/      PC

On March 12, 2007 a follow-up was done for the right eye and a new left lens was dispensed. He stated that he was doing very well with the right lens and his wearing time was up to about eight hours. The acuity in the right eye was 20/20, the left eye was 20/50 with the new contact lens in place. The over refraction in the right eye was Plano and with the left lens held in place, the over refraction was -0.75. The fit of the contact lens was 1+ flat peripheral edge and the central curvature was slightly flat. However, with a blink, the lens would not stay in place for more than five minutes. Another new contact lens was ordered for the left eye with a prescription of:

        Lenticular / Boston XO
OS   67.75 / -25.75 / 8.4 / 6.4 / .2/5.70 .3/6.10 .3/7.00 .2/9.00
        BC   / Power / Dia / OZ /      PC

The new contact lens for the left eye was dispensed on March 19, 2007. The acuity with the initial right contact lens was 20/20^-0 with a Plano over refraction. With the new contact lens dispensed for the left eye, the acuity was 20/50⁺¹, with a Plano over refraction. Evaluation of the fit of the new left contact lens revealed that it was fitting on contour. The edge of the contact lens were in close proximation to the cornea with no significant lift-off. This lens was dispensed and a follow-up was scheduled for one week.

The next follow-up was performed on March 26, 2007. At which time, he stated that the right lens was still doing extremely well, but the left lens was popping out after approximately 15 to 20 minutes and was still unstable on the eye. He was not wearing the left lens at this visit. I proceeded to refit the left eye into a new contact lens. I placed a Dyna Intralimbal lens on the left eye with a prescription of:

        Dyna Intralimbal
OS   55.00 / -11.25 / 11.2 / 9.4 / STD
        BC   / Power / Dia / OZ /      PC

This lens stayed well in place and exhibited approximately ½ to ¾ mm movement. There was a slight flat central region and the edges were 1+ flat. With an over refraction of -3.00, he was able to read 20/50+. A new contact lens was ordered for the left eye with a prescription of:

OS   55.00 / -14.25 / 11.4 / 9.4 / STD      Dyna Intralimbal Menicon Z
        BC   / Power / Dia / OZ /      PC

As of the date of this report, the contact lens has not yet been dispensed to the patient. However, I am confident because of the better centration and with the fit of the lens under the upper lid that this will eventually be a good and stable fit.

DISCUSSION:
Discussion of the fitting process is to contrast the differences between mild keratoconus and extreme keratoconus. Upon evaluation of the topography for the right eye, there is a notable temporal cone which was only moderate in steepness. Because of the cone being located centrally, a fairly standard lens design could be used. I used a larger diameter lens than the initial trial lens in an attempt to vault over the cone and obtain an upper lid attachment. I used the multiple peripheral curve design to allow flaring of the edge of the lens with a fairly flat third peripheral curve to ensure that the lens would obtain proper movement and edge lift. Even though this contact lens is not steep by keratoconic standards, I was able to use a larger OZ as compared to the fitting lens to allow this to vault over the cone and again, obtain good centration and movement.

By contrast, in the left eye, we have an extremely advanced cone and with all attempts to design a standard cone design, the lens would not stay in position on the eye. I was able to obtain a good fit in terms of the slit lamp evaluation; however, due to the small diameter and the lens centering somewhat inferior, the lens would catch the lid and would not stay in place. So I proceeded with the use of a larger diameter lens which is the Dyna Intralimbal lens. I have had good success with the Dyna Intralimbal lens in these situations; however, it has its own set of fitting problems. Over time, this lens tends to tighten on the eye and have significant bearing on the peaks of the cone, which in turn will cause puntate kerititis and possible abrasions. I do not normally proceed with this particular lens unless the standard design does not work.

I present both of these cases for discussion and to provide contrast between a mild cone and a very significantly advanced cone.

Go to Case 1
Go to Case 2
Go to Case 3
Back to top