MANAGING THE IRREGULAR CORNEA

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Many hard-to-fit patients do well with the Maxim 7 scleral from Accu Lens.
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Metro Optics’ RevitalEyes PRS lens works by having peripheral curves to match the unaltered peripheral cornea while having a flatter central curve to match the post-surgical central profile of the cornea.
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Galilei mapping shows inferior steepening on the anterior corneal curvature map in a 16-year-old male.

Though they can be challenging cases, there are more and more options for patients needing scleral lenses.

Managing patients with irregular corneas, both optically and surgically, can provide some of the most rewarding experiences of one’s career. These patients tend to be difficult to oversee as normal spectacle or traditional soft contact lens wear is often not an option for achieving full visual potential.

Thankfully, the advancements in our field have progressed where there are now a host of alternatives to help patients achieve superior visual results, maintaining both ocular health, as well as stabilizing aggressive ectatic disease. The case studies that follow are examples of how implementing the latest technologies””along with a dose of creativity””can help solve the most challenging situations.

A CROSS-LINKING SUCCESS
A 16-year-old male presented to our clinic as a referral for keratoconus OU. He had a chief complaint of decreased vision OD>OS over the past year as well as a medical history of asthma and environmental allergies. He also had an ocular history significant for keratoconus for two years OD>OS and intolerance to RGP wear.

Entering uncorrected acuities were 20/70 OD, 20/30 OS. Manifest refraction yielded acuities of 20/40 OD, 20/25 OS. Slit lamp examination revealed grade 2 papillae, moderate apical thinning, and Vogts striae in both eyes. Corneal tomography using the Galilei G2 revealed inferior steepening as well as “posterior float” OD>OS. Corneal ultrasound pachymetry using the Pachmate was 450 microns OD, 503 microns OS. All other exam findings were within normal limits.

With subjective complaints of decreasing vision and objective findings that confirmed keratoconus OD>OS, we decided to undergo corneal collagen cross-linking (CXL) in both eyes to stabilize and arrest the progression of his corneal ectasia. We also decided to manage his allergic conjunctivitis concurrently with ocular allergy testing and topical Pataday in both eyes.

CXL is a surgical procedure that has been around for the better part of 15 years, but is a relatively new procedure in the U.S. When used in the treatment of corneal ectasia, CXL is designed to strengthen the cornea and halt progression of corneal ectasia. CXL does this by way of using riboflavin and UVA light (365nm) in conjunction with one another which increases collagen covalent bonds and increases collagen fiber diameter in the corneal stroma. Corneal cross-linking’s primary goal, as mentioned previously, is to stop progression of corneal ectasia and while it may have some visual benefit the benefit on average is mild.

Following CXL we decided to pursue a scleral contact lens fit for this patient. We opted for the Maxim™ 7 scleral (from Accu Lens); the right eye was fit with a Maxim 7 BC 7.34 OAD 17.5 Power -4.75 SAG 544; the left eye with a Maxim 7 BC 7.50 OAD 16.5 Power -3.25 SAG 488. His visual acuity was 20/15 OD, OS and slit lamp examination revealed a good fit with 200 microns of central clearance, limbal clearance 360°, and no conjunctival impingement OD, OS. The patient has since shown no ectatic progression and notes good comfort and vision with his scleral contact lenses.

KERATOECTASIA AND INTACS
A 62-year-old female was experiencing Keratoectasia OD when she came to our clinic. Her chief complaint was poor vision at distance that was not improved with spectacle wear. She also noted previous intolerance to contact lens wear. Ocular history was significant for conductive keratoplasty (CK) in 2005 OU, PRK in 2006 OU, and intra-stromal ring implantation (INTACS) in 2007 OS.

Entering uncorrected visual acuity was 20/400 OD. Manifest refraction was +3.75 -3.75×092 20/60 OD. Slit lamp examination OD revealed multiple CK scars as well as moderate apical thinning. Atlas corneal topography obtained by the referring doctor confirmed diagnosis of keratoectasia OD.

Secondary to her history of INTACS in the fellow eye, we decided to pursue INTACS OD. Corneal topography using the Magellan corneal topographer was obtained three months following her surgery and revealed corneal flattening and marked reduction of irregularity in the anterior corneal curvature. Manifest refraction post-procedure was +2.50 -0.75×045 20/20 OD.

It’s important to note that while CXL is designed to arrest progression of corneal ectasia, INTACS is intended to flatten the central cornea and reduce irregularity. INTACS tends to have a much more dramatic effect on a patient’s best spectacle corrected vision and corneal shape.

Following her three-month visit, she expressed interest in obtaining independence from glasses and so was fit in Maxim 7 scleral lenses OD for distance, OS for near. Her right eye was fit with a Maxim 7 BC 7.50 Power -0.50 OAD 16.0 SAG 447 which showed 175 microns of central clearance, limbal clearance 360°, and  mild edge lift nasally and temporally. Her left eye was fit with a Maxim 7 BC 7.03 Power -0.25 OAD 16.0 SAG 464 which showed 150 microns of central clearance, limbal clearance 360°, and mild edge lift nasally and temporally.

Visual acuity was 20/20-1 at distance OU and J2 at near OU. These lenses were dispensed to the patient while new lenses were ordered with slightly steeper toric peripheral curves at 3 and 9 in both eyes to improve the landing zone of the lenses in both eyes. Further follow-up resolved the issue and there was no evidence of conjunctival impingement, entrapment, or edge lift 360° in either eye.

INTOLERANCE ISSUES
A 49-year-old male presented to our clinic as a referral for a contact lens fitting OD, OS. His chief complaint was blurred vision OD, OS secondary to irregular astigmatism caused by radial keratotomy in 1984. He noted poor vision with spectacle lens wear and intolerance to scleral contact lens wear in the past.

Secondary to history of irregular astigmatism, his flat keratometry values, and his history of intolerance to scleral lens wear, we decided to try Metro Optics’ RevitalEyes PRS series in both eyes. The RevitalEyes PRS lens is a soft specialty lens that works by having peripheral curves to match the unaltered peripheral cornea while having a flatter central curve to match the post-surgical central profile of the cornea. After a few parameter and power changes over a period of a few weeks we were able to achieve 20/20 distance acuity as well as good comfort in both eyes.

Hopefully these examples have illustrated how both CXL and Intacs can delay or even eliminate the need for a penetrating keratoplasty which carries a higher risk. In some cases it provides no improved refractive results, not to mention that it has the constant threat of graft rejection which can make life difficult, especially for younger patients.

With the increasing presence of scleral contact lenses and advances in the specialty contact lens market we can provide those with irregular corneas comfortable contact lens wear with drastically improved vision.

Bryce Brown practices at Mile High Corneal Specialists in Denver, CO.

WHERE TO FIND IT:

Accu Lens •800-525-2470 •acculens.com

Metro Optics •800-223-1858 •metro-optics.com

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