As many as 50 percent of older Americans needing cataract surgery and 30 percent of younger patients who desire elective LASIK eye surgery show some degree of ocular surface disease, says surgeon Richard L. Lindstrom, MD, in a recent article published in Ocular Surgery News.

Dr. Lindstrom, a board-certified ophthalmologist, is founder of Minnesota Eye Consultants (Minneapolis) and Adjunct Professor Emeritus at the University of Minnesota Department of Ophthalmology.

He believes there are four stages of ocular surface disease treatment that cataract and refractive surgeons should carefully manage to enhance their patients’ surgical outcomes:

1. Preparing the cornea prior to surgery
2. Protecting the cornea during surgery
3. Rehabilitating the eye surface after surgery
4. Long-term management of the condition of the eye surface after surgery

For optimum outcomes of patients with dry eye, blepharitis, eye allergies and other eye surface problems, Dr. Lindstrom recommends these general treatment strategies:

Prior to surgery. Treat pre-existing ocular surface disease with eye drop medicines four-times-a-day for 1 to 2 weeks prior to surgery. This treatment can be combined with artificial tears, punctual occlusion, lid hygiene, nutritional supplements and other appropriate therapies.

During surgery. Use a viscous lubricating gel to coat the exterior of the eye during surgery to prevent the corneal epithelium from drying out.

After surgery. A combination of frequent use of artificial tears with twice-daily use of prescription eye drops to improve tear production (Restasis). In some cases of post-LASIK dry eye, this regimen may need to be extended for months to ensure adequate lubrication of the eye is restored.

Long-term maintenance. Patients who have dry eye or other ocular surface disease prior to cataract or LASIK surgery generally will still have the problem after surgery. Dr. Lindstrom says eye doctors need to educate these patients about their problem and the need for long-term treatment.

In a related article published recently in Review of Ophthalmology, LASIK surgeon Karl Stonecipher, MD, agrees with Dr. Lindstrom’s assessment of the need for careful management of ocular surface disease prior to cataract and laser eye surgery.

Dr. Stonecipher, medical director for TLC Laser Eye Centers in Greensboro, N.C., says he routinely prescribes steroid and antibiotic eye drops for use 4 times a day for 3 days prior to cataract and LASIK eye surgery — even for patients with no overt signs of ocular surface disease.

He says this pre-operative regimen gives him greater confidence in eye measurements taken the day of surgery and also has increased the predictability of surgical outcomes.

Dr. Stonecipher also says that though this pre-operative regimen is not yet commonplace among LASIK surgeons, he feels the addition of medicines prior to surgery does not significantly increase LASIK eye surgery cost, and that the potential benefits of a healthier ocular surface prior to surgery outweigh concerns about added costs or patient compliance.

SOURCES:
1. Ocular surface disease needs to be managed before and after surgery. Ocular Surgery News, U.S. edition. December 10, 2009.
2. First things first: Maximizing corneal health preop. Review of Ophthalmology. November 2009.

That’s the conclusion of Canadian researchers in a report published in this month’s issue of the Journal of Cataract and Refractive Surgery.

The investigators conducted a systematic review of several studies that evaluated the effect of surgical removal of cataracts shortly after they were discovered as a measure to improve vision and reduce the risk of injury among older adults. Both published and unpublished studies dating from 1950 to 2008 were included in the research.

Vision data from 737 patients were included in the analysis. Analysis of the data showed that expedited cataract surgery significantly improved visual acuity in most cases. But analysis of pooled data from 535 patients showed only a slight reduction in the risk of falls after cataract surgery that was not statistically significant.

The researchers concluded that accumulating evidence indicates expedited cataract surgery is effective in significantly enhancing vision but is inconclusive in preventing falls.

The results of the study are contrary to earlier research published in the April 2007 issue of the Canadian Medical Association Journal (CMAJ), which found evidence that vision and quality of life decrease and the rate of falls increases among patients during the waiting period for cataract surgery.

SOURCES:
1. Vision improvement and reduction in falls after expedited cataract surgery: Systematic review and meta-analysis. Journal of Cataract and Refractive Surgery. January 2010.
2. The consequences of waiting for cataract surgery: a systematic review. CMAJ. April 24, 2007.

Researchers in Belgium have found just the opposite: LASEK eye surgery appears to reduce pre-operative retinal straylight, which is a potential source of glare. The results of their study suggests patients undergoing LASEK for the correction of myopia may have reduced glare after surgery, especially if they wore soft contact lenses prior to the procedure.

Retinal straylight is light that is scattered by defects in the optical media of the eye and therefore is not available to be focused into a clear image by the retina. This scattered light reduces the contrast of images created by the retina and contributes to glare.

To quantify the changes in retinal straylight after LASEK eye surgery, researchers at Antwerp University Hospital (Edegem, Belgium) evaluated straylight values of 86 eyes of 49 patients scheduled for LASEK surgery.

Straylight measurements were taken prior to LASEK surgery and 6 months after the procedure, using a device called the Oculus C-Quant straylight meter (Oculus Optikgeräte GmbH, Wetzlar, Germany).

Straylight values also were compared with values in a “normal” reference database.

Patients were divided into four groups, based on their habitual method of vision correction prior to surgery:

• Rigid contact lenses
• Soft contact lenses
• Spectacles after a period of contact lens wear
• Spectacles only

Analysis of the pre-operative data revealed that age-corrected straylight values were significantly elevated among patients in the study, especially if they wore soft contact lenses full-time prior to LASEK surgery.

Six months after LASEK, straylight values for all patient groups had returned to normal levels, regardless of the amount of nearsightedness and method of vision correction prior to surgery.

The researchers concluded that higher-than-normal retinal straylight values normalized after LASEK refractive surgery among this patient population.

They also said that wearing soft contact lenses causes higher pre-operative retinal straylight, which is eliminated after LASEK.

SOURCE:  Straylight before and after LASEK in myopia: Changes in retinal straylight. Investigative Ophthalmology & Visual Science. Published online ahead of print December 10, 2009.

The retrospective study followed 455 eyes that underwent photorefractive keratectomy (PRK) for a period of up to nine years after surgery.

Carole Liernur, MD, presented the results of the study at the annual meeting of the European Society of Cataract and Refractive Surgeons (ESCRS) held last week in Barcelona, Spain.

Prior to PRK, all eyes were myopic, ranging from -1.00 to -10.00 diopters (D) of nearsightedness. In all cases, the PRK procedure was performed with a Nidek 5000 excimer laser.

No patients experienced a detached retina during the follow-up period, and only one patient complained of floaters in one eye. This single case of vitreous floaters was most likely related to the natural history of myopia in this patient rather than the PRK procedure, Dr. Liernur said.

PRK eliminates one LASIK risk

Some clinical studies have reported retinal detachment as an infrequent complication of LASIK eye surgery, especially in patients with high myopia. This study set out to determine if PRK has the same LASIK risks for vitreo-retinal complications (affecting the vitreous and/or retina in the back of the eye).

Since no LASIK-style corneal flap is created during PRK, no suction device is attached to the eye to hold it still for this step. The suction device used in LASIK increases the pressure inside the eye, and when the device is removed after the flap has been created, the internal eye pressure quickly returns to normal.

This significant and sudden change in internal eye pressure may weaken the retina in susceptible individuals, increasing the risk for a retinal detachment during or after LASIK.

This study appears to support the belief that PRK does not pose the same risk of vitreo-retinal complications.

Dr. Liernur also said that risks associated with PRK surgery — specifically, corneal haze and post-operative discomfort — can be alleviated with new surgical techniques and topical pain medications.

SOURCE:  No vitreoretinal complications reported after PRK in long-term case series. Ocular Surgery News website (OSNsupersite.com). September 21, 2009.

A retrospective review of 2,000 eyes treated with all-laser LASIK using an IntraLase femtosecond laser to create an extra-thin corneal flap, only one case of central corneal ectasia was reported.

The laser-created flaps in all cases were designed to be 90 microns thick. By comparison, conventional microkeratome-created LASIK flaps in the past have frequently been 160 microns or thicker (though modern bladed microkeratomes are capable of creating thinner flaps as well.)

The one case of post-LASIK ectasia in the study was reported six months after surgery. Patients in the study were monitored for up to three years after the thin-flap LASIK procedure.

Corneal ectasia after LASIK

Corneal ectasia is an apparently rare but serious LASIK complication. It is characterized by an irregular outward bulging of the cornea similar to the eye disease keratoconus.

One possible risk factor for ectasia is failure to leave adequate corneal thickness under the flap created in LASIK surgery to preserve the biomechanical strength and stability of the cornea.

Because of this potential, many refractive surgeons in recent years have chosen to create thinner corneal flaps during the LASIK procedure to preserve greater corneal thickness under the flap.

Though there are promising new treatments for corneal ectasia, the condition can cause permanent vision loss. In severe cases, a corneal transplant may be required to restore vision.

Careful pre-operative screening is key to ectasia prevention

Experts agree that careful pre-operative screening of patients can reduce the risk of post-LASIK ectasia. Corneal topography measurements often can identify patients who may have signs of subclinical keratoconus or other corneal abnormalities and therefore are not good candidates for laser vision correction surgery.

In the current study, investigators re-examined the pre-operative corneal topography measurements of the one patient who developed post-LASIK ectasia and found signs of subclinical keratoconus.

Post-LASIK ectasia: conclusions

Nader Robin, MD, presented the results of the study at the annual meeting of the European Society of Cataract and Refractive Surgeons (ESCRS) held this week in Barcelona, Spain.

Though only one case of ectasia was noted in the study, Dr. Robin said post-LASIK ectasia can occur months or even years after surgery and therefore longer follow-up studies are needed to draw more reliable conclusions about the risks of ectasia after LASIK.

SOURCE:  Thin-flap LASIK with femtosecond laser may help avoid iatrogenic ectasia. Ocular Surgery News website (OSNsupersite.com). September 18, 2009.

Recently, a variation of LASIK called sub-Bowman keratomileusis (SBK) or “thin-flap LASIK” has been gaining popularity among LASIK surgeons. A thinner corneal flap is created in SBK, which may reduce certain LASIK risks — particularly dry eyes and corneal ectasia.

To compare the outcomes produced by thin-flap LASIK with those produced by PRK, researchers Stephen G. Slade, MD, Daniel S. Durrie, MD, and Perry S. Binder, MD, recently conducted a study of 50 patients, performing thin-flap LASIK on one eye and PRK on the other eye of each patient.

Thin-flap LASIK vs PRK: Study design and methods

Of the 100 eyes in the study, the mean pre-operative refractive error was -3.66 diopters (D) of nearsightedness and -0.66 D of astigmatism.

Eyes in the thin-flap LASIK group had a corneal flap created with a 60-Hz IntraLase femtosecond laser (Abbott Medical Optics, Santa Ana, CA). The intended flap thickness was 100 microns, which is about 20 to 40 percent thinner than conventional LASIK flaps.

All eyes in both groups underwent a customized laser ablation with a LADARVision 4000 CustomCornea excimer laser (Alcon Laboratories, Fort Worth, TX)

Follow-up exams were performed one, three and six months after surgery. Measurements performed at each visit included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), contrast sensitivity, corneal topography and wavefront aberrometry.

Thin-flap LASIK vs PRK: Study results

Data gathered during the follow-up visits yielded the following results:

• One month after surgery, 88 percent of thin-flap LASIK eyes achieved UCVA of 20/20 or better, compared with 48 percent of PRK eyes.
• Six months after surgery, there was no significant difference in UCVA of eyes in the two groups: 92 percent of thin-flap LASIK eyes and 94 percent of PRK eyes had UCVA of 20/20 or better.
• At one and three months, the thin-flap LASIK eyes had less significant higher-order aberrations (including spherical aberration) than the PRK eyes.
• Six months after surgery, there was no significant difference in higher-order aberrations between the two groups.

Thin-flap LASIK vs PRK: Study results

The researchers concluded that quality of vision recovered faster in eyes undergoing thin-flap LASIK compared with eyes undergoing PRK, but at six months there were no significant visual differences between the two groups.

The results of the study show that both thin-flap LASIK and PRK produce excellent visual outcomes.

One implication of this study if you are considering laser vision correction and want no possible risk of LASIK flap complications, PRK provides comparable visual acuity to thin-flap LASIK, but you probably will have to wait a few weeks longer after surgery for optimum visual acuity.

SOURCE:  A prospective, contralateral eye study comparing thin-flap LASIK (sub-Bowman keratomileusis) with photorefractive keratectomy. Ophthalmology. June 2009.

Optical Express is Europe’s largest provider of laser vision correction and employs over 3,000 optometrists, refractive surgeons and support staff in the United Kingdom, Ireland, the Netherlands, Germany, France, Croatia and the United States, according to the company.

Wavefront-guided LASIK: Study design and methods

Data were gathered from the electronic records of 17,713 patients (32,569 eyes) who underwent wavefront-guided LASIK at Optical Express refractive surgery centers in 2008. The procedures were performed by 30 LASIK surgeons at 40 Optical Express centers.

All procedures were performed using the STAR S4 IR excimer laser system (Abbott Medical Optics) using a wavefront-guided ablation profile (Advanced CustomVue, AMO).

All patients had low to moderate myopia with or without astigmatism prior to surgery. The mean spherical equivalent amount of pre-operative myopia was -2.97 diopters (range: -0.37 to -6.00 D).

The majority of corneal flaps (75.7 percent) were created with an IntraLase FS-60 femtosecond laser (AMO). The remaining flaps were created with a Moria Evo3 One Use-Plus microkeratome (Moria SA).

Patients ranged in age from 18 to 69 years, with an average age of 35.6 years.

Wavefront-guided LASIK: Study results

Data gathered one month after surgery yielded the following results:

• 92 percent of eyes achieved uncorrected visual acuity (UCVA) of 20/20 or better.
• 99 percent of eyes achieved UCVA of 20/40 or better.
• 94 percent of eyes were within 0.50 D of the intended correction.

Intra-operative LASIK complications occurred in 25 eyes (0.06 percent). The most common of these complications (22 eyes; 0.05 percent) were related to flap creation with a microkeratome. (Numbers and percentages based on 42,143 eyes treated in 2008. Not all patients returned for the 1-month follow-up visit of the study, which comprises 32,569 eyes.)

Post-operative LASIK complications occurred in 210 eyes (0.64 percent). The most common complications were dry eyes (58 eyes) and mild diffuse lamellar keratitis (58 eyes).

Conclusions

The researchers concluded that wavefront-guided LASIK can safely and effectively correct low to moderate myopia, with or without astigmatism.

The also said the low overall rate of complications in this large study (intra-operative: 0.06 percent; post-operative: 0.64 percent) reflects the high level of safety that modern LASIK has achieved.

SOURCE: One-month outcomes of wavefront-guided LASIK for low to moderate myopia with the VISX STAR S4 laser in 32,569 eyes. Journal of Refractive Surgery. July 2009. (Supplement: Clinical Outcomes and Quality of Care in Refractive Surgery, sponsored by Optical Express.)

Of the 500 surgeons on the Panel, 31 responded to the survey.

Among the results:

• 72 percent of the respondents say they have modified their surgical approach to reduce LASIK risks, especially the risk of ectasia — a rare but serious LASIK complication that can cause permanently reduced vision.
• Approaches respondents are using to reduce the risk of ectasia include: paying more attention to pre-existing optical aberrations of the eye when screening LASIK candidates; using a more conservative criterion for minimum residual corneal thickness under the LASIK flap after surgery; creating thinner LASIK flaps with a femtosecond laser to preserve corneal thickness under the flap.
• Regarding laser vision correction preferences, 55 percent of the respondents prefer wavefront-guided LASIK, 20 percent prefer conventional LASIK and 15 percent prefer PRK.
• 73 percent of the LASIK surgeries performed by the respondents are custom LASIK procedures.
• The average LASIK cost charged by the respondents is $2,273 per eye.

If an enhancement surgery is needed to improve visual outcomes of LASIK, 82 percent of the respondents say they prefer to lift the original LASIK flap and the rest say they prefer to perform a surface ablation procedure such as PRK.

SOURCE:  National Panel reflects on refractive surgery. Review of Ophthalmology. July 2009.

The RLE procedure is essentially the same as procedure used for modern cataract surgery. The only difference is that the lens being removed from the eye is clear, not clouded by cataracts.

Many surgeons are reluctant to perform RLE for purely refractive reasons due to the potential for serious complications, such as glaucoma and retinal detachment. Other surgeons, however, point out the low incidence of such complications in both RLE and modern cataract surgery.

RLE safety and effectiveness: Study design

To investigate the safety and effectiveness of refractive lens exchange for the treatment of moderate and high hyperopia, researchers in Indonesia treated 153 eyes with the procedure.

The mean refraction of the eyes prior to surgery was +5.29 diopters (D) and the mean age of the patients was 52 years.

Three different IOLs were investigated, including multifocal IOLs for the treatment of presbyopia. Mean follow-up after surgery was more than five years.

RLE safety and effectiveness: Study results

Amit Tarafdar, MD reported the results of the study at he joint meeting of the Asia-Pacific Academy of Ophthalmology and the American Academy of Ophthalmology held recently in Bali.

Findings of the study included:

• Mean refraction after surgery improved to 0.04 D, compared to +5.29 D prior to the procedure.
• Uncorrected visual acuity (UCVA) at near was 20/20 in more than 90 percent of the subjects.
• There were no occurrences of intra-operative or post-operative complications and no instances of detached retina folowing surgery.

“Clear lensectomy (and RLE) for hyperopia is predictable and extremely safe,” Dr. Tarafdar said. “Results are acceptable for monofocal lenses and extremely good for multifocal lenses.”

Surgeons prefer RLE for high hyperopia, but not high myopia

In related news, a recent survey of refractive surgeons in the American Society of Cataract and Refractive Surgery (ASCRS) found that a majority of surgeons prefer RLE for the surgical treatment of high (+5.00 D) hyperopia, compared with only 9 percent of respondents preferring LASIK for these patients. (Thirty percent of those surveyed said they prefer not to perform either type of surgery on these patients.)

But it is a different story for the correction of high myopia. For patients with -10.00 D of nearsightedness, 40 percent of surgeons surveyed say they prefer phakic IOL implantation, 20 percent prefer LASIK and only two percent prefer RLE.

The difference is due to the higher risk of retinal detachment and other RLE complications among eyes with high myopia compared to eyes with high hyperopia.

SOURCE:  RLE shown safe and effective in moderate, high hyperopia. Ocular Surgery News website (OSNsupersite.com). May 16, 2009.