Laser Vision Correction in Patients with High Astigmatism

A 40-year-old male presented to the Clarity clinic to seeking laser vision correction. Vision was correctable to 20/20 OU with -0.25-2.50×10 OD and plano-4.25×160 OS. He reported a vague history of amblyopia and patching therapy for the left eye in childhood. His medical history was non-contributory.

External and slit lamp examinations were unremarkable. Wave scan studies (Figure 1) showed lower order aberration of -0.05-1.99×11 OD and +0.39-4.50×159 OS. Pentacam elevation tomography demonstrated sagittal power maps (Figure 2) compatible with the clinical presentation with central corneal pachymetry of approximately 560 microns OU. Keratometric readings were 41.6/45.3×64 in the left eye.

 

Discussion of Treatment Options:

High levels of astigmatism OS placed the left eye outside of the range of refractive errors treatable with custom wave scan technology (3.50 diopters). This left us with the option of treating the problematic eye with past standard excimer laser technology or approaching the problem with a staged approach, treating the high levels of astigmatism initially with femtosecond technology and then following up with custom LASIK after allowing for a suitable period of stability. After a full review of his clinical status and discussion of inherent risk and benefits the patient elected to pursue femto AK as an initial treatment with definitive custom wave scan guided LASIK to follow after refractive stabilization.

 

Treatment Course

On 3/15/13 a refractive surgical procedure consisting of custom Intralase LASIK OD and Intralase Femtosecond Arcuate Keratotomy OS was performed. The AK parameters consisted of paired 80-degree arcuate cuts centered on the 60-degree steep axis at an 8.0 mm optical zone. Incision depth was calculated at 75% of the thinnest ultrasonic pachymetry reading measurement in the 8.0 OZ and incisions were angled at 105 degrees. Following creation of the arcuate AK cuts with Intralase the incisions were opened with a Sinskey hook and a bandage contact lens was placed. Postoperative care consisted of topical steroids and antibiotics given at a frequency identical to that administered with postoperative LASIK care.

The postoperative course of the patient was uneventful with uncorrected day one visual acuity OD 20/20 and 20/50 in the FemtoAK treated eye with Wave scan documented refractive error of -1.13-1.29X172 (Figure 3). The patient was advised that following demonstration of refractive stability on two successive monthly follow up examinations that we would proceed with the LASIK component of his treatment for the OS. Stability was apparent in two months and LASIK was performed thereafter yielding 20/25 uncorrected acuity and a happy patient.

 

Discussion:

One of the seminal developments in the field of laser vision correction has been the application of wave scan technology to our excimer laser ablations in the treatment of myopia, hyperopia and astigmatism. It has allowed for a profound precision and customization allowing us to measure and to treat both lower order and higher order aberrations thus giving our refractive surgery candidates a more comprehensive treatment often resulting in uncorrected visual results better than 20/20. Not only do wave scan custom treatments allow us to treat higher order aberrations with improved refractive outcomes, they have been equally effective in reducing annoying quality of vision issues after surgery as well. CustomVue Wavescan guided excimer ablations also allow the surgeon to make use of sophisticated tracking technology assuring that patients with higher levels of astigmatism are more accurately treated in terms of critical axis alignment.

In the case in question the use of precise Intralase femtosecond AK incisions allowed us to bring our patient into range for a superior excimer laser LASIK treatment. Although it did require some patience, as we had to wait for refractive stability, the excellent outcome was worth the wait.

 

 

Author
Dr. Fox

You Might Also Enjoy...

Femtocataract Refractive Cataract Surgery

A 55-year-old female CEO presented for refractive surgical consultation at the Clarity Center with complaints of steadily declining uncorrected visual acuity with problems both at distance and near range.

Choosing from the Refractive Menu

The science and art of modern refractive surgery continues to evolve with breath taking speed to the point that it now qualifies as a bona fide surgical subspecialty within the field of eye care.

Laser Assisted Keratoplasty in Rapidly Progressive Keratoconus

A 30 year old car salesman presented in August 2011 with history of a rapidly progressive ectactic dystrophy which was creating a significant impact on visual function and the ability to work. Patient was wearing a hybrid contact lens with reasonable comfo

Collagen Cross Linking in the Treatment of Keratoconus

A 21-year-old Hispanic male presented to the Clarity Refractive clinic in January 2013 referred by his family optometrist with newly diagnosed Keratoconus Attempts at finding an adequate spectacle correction or contact lens fit had been thus far unsuccessf