Surveys show patient satisfaction high, night vision improved with custom ablation

Most patients treated with the three FDA-approved wavefront-guided systems report improvements in glare, halos and quality of night vision.

Patients in the clinical trials of the Alcon, Bausch & Lomb and Visx wavefront-guided custom ablation systems report higher satisfaction with their postoperative nighttime visual results than their preoperative night vision, according to investigators of all three systems.

Surveys of patients in the clinical trials for Food and Drug Administration approval of the Alcon CustomCornea, Bausch & Lomb Zyoptix and Visx CustomVue wavefront-guided customized ablation systems all found decreases in many patients’ night vision problems, according to investigators.

“These improvements are possible because wavefront-guided LASIK corrects higher-order aberrations without inducing new aberrations,” Daniel S. Durrie, MD, medical monitor of the Alcon CustomCornea clinical trial, told Ocular Surgery News.

Researchers found decreases from preoperative levels in patients’ complaints related to poor night vision with all three systems, as well as increases in overall satisfaction with vision.

“The overall satisfaction of patients’ visual outcome appears to be higher when compared to my standard LASIK patients,” said Colman R. Kraff, MD, a lead investigator in the Visx CustomVue clinical trial.

“Issues relating to night vision really went against the grain of traditional thought about LASIK,” Dr. Durrie said. “People say, ‘LASIK causes dryness, glare and halos at night.’ But these patients told us that wavefront-guided LASIK did not induce significantly more glare and halo.”

“Patients said that their night vision improved, and they had absolutely no complaints postop,” agreed Stephen G. Slade, MD, medical monitor of the clinical trial for Bausch & Lomb’s Zyoptix system.

Wavefront patients report less dry eye

LASIK patients treated with the Alcon Custom Cornea wavefront system reported an improvement or no change in their dry eye symptoms, said Daniel S. Durrie, MD. Dr. Durrie called the results “impressive” when compared to standard LASIK patients, who often complain of heightened dry eye after surgery. In the Alcon FDA clinical trials, 2% of patients reported “significantly worse” dry eye symptoms 6 months after surgery compared to 7.4% at 3 months. As symptoms decreased, improvements increased. Six percent of patients reported “significantly better” symptoms at 3 months postoperatively; 8.1% reported the same level of improvement at 6 months postoperatively. “Surface abaltion causes temporary dryness that improves over time,” Dr. Durrie said. “We need to tell our patients that at 3 months, dry eye symptoms may persist, but by 6 months, they usually resolve.”

“This new data gives surgeons the ability to say with much more confidence that the likelihood of having significant problems with wavefront with respect to night vision, glare and halos is potentially minimized,” Dr. Kraff said.

Taken together, more than 1,100 eyes were treated in the phase 3 clinical trials of the three customized ablation systems. Researchers distributed questionnaires to more than 500 patients in the three trials. Among other responses, patients subjectively graded their preoperative and postoperative experience of glare, halo and their quality of night vision. Questionnaire results from patients treated with each system are reviewed in this article.

Improving night driving vision

In a survey of patients in the Alcon trial, quality of vision was reported as unchanged, better, or significantly better by 89.8% of patients at 3 months and 88.3% of patients at 6 months.

“Eighty-five percent of patients at 3 months and 79.4% of patients at 6 months were satisfied or extremely satisfied with their results,” according to an Alcon CustomCornea LASIK Physician’s Booklet.

Night driving difficulty was reported as improved from preoperatively by 6.6% of patients and significantly improved by 12.5% of respondents to the Alcon survey. No change in night driving difficulty was reported by 61.8% of patients. Eighteen percent of patients reported worse night driving difficulty, and 0.7% said it was significantly worse.

“You have two extremes here,” Dr. Durrie said of the Alcon respondents; “6.6% of people were significantly better with wavefront-guided LASIK, while only 0.7% were significantly worse with it. The grid’s been shifted; people are coming out with positive outcomes. The trend in visual disturbances is decreasing.”

Among the Alcon respondents, halos were rated as better than preoperatively by 6.6% and significantly better by 5.1%. No change was reported by 75% of respondents, and 13% reported worse halos. None reported significantly worse halos.

“We can say that no patient in the Alcon clinical trial had significantly worse halos after surgery, and 5.1% had a significant decrease in halos,” Dr. Durrie said.

He said these results suggest it is “very unlikely” that a CustomCornea patient’s visual problems at night, resulting from glare and halo, would become significantly worse after surgery.

Large pupil patients happy

Similar responses were seen from patients in the Visx clinical trials.

Preoperatively, patients were asked about their satisfaction with their night vision when wearing correction; 65% of respondents said they were either satisfied or very satisfied.

At 6 months postoperatively, the patients were asked about their satisfaction without correction; at that time, 85% of respondents said that they were satisfied or very satisfied with their postoperative night vision without correction, Dr. Kraff noted.

Regarding night vision with glare, 81% of postoperative patients were satisfied or very satisfied, compared to 60% before surgery, he said.

Dr. Kraff noted that about the same percentage of patients in the Visx survey, 76%, said they experienced halos around lights “rarely or never” both before and after surgery, so there was no reported increase in this symptom.

Dr. Kraff noted that the improvement in night vision was also seen in people with large pupils treated with the Visx system.

“In the past, these patients have been the hardest to please,” Dr. Kraff said. “People with larger pupils are often more dissatisfied with their nighttime vision. You would expect this group to have the largest complaints, but this was not the case. People with the largest pupils were the happiest with their nighttime vision. This was very surprising.”

The questionnaire responses were analyzed in relation to preoperative pupil size. Patients were categorized into three groups: small pupils (6 mm or less), average-sized pupils (6.1 mm to 7.5 mm) and large pupils (greater than 7.5 mm).

Preoperatively, 69% of patients with small pupils and 65% of patients with average-sized pupils were satisfied or very satisfied with their night vision. Of patients with large pupils, 58% were satisfied or very satisfied with their preoperative night vision.

“After surgery, satisfaction jumped from 58% to 89% of large pupils who were happy with their night vision,” Dr. Kraff said. Similarly, 87% of patients with small pupils and 83% of patients with average-sized pupils reported satisfaction with their night vision.

Similar outcomes occurred in regard to glare. In the largest pupil group, 81% reported satisfaction after surgery as compared with 51% preoperatively, Dr. Kraff said.

He attributed the high level of satisfaction in large-pupil patients to the variable spot scanning of the Visx system and the use of wavefront data to correct higher-order aberrations.

Improved contrast sensitivity

Patients in the Bausch & Lomb Zyoptix wavefront trials also answered questionnaires. According to company materials, about 40% of patients reported having better night driving vision 6 months postoperatively than they did before surgery.

Dr. Slade noted that in addition to the subjective survey results, clinical tests also seemed to confirm this improvement in night vision. While survey results on night vision are encouraging, he cautioned, they should not be equated with scientific findings.

“We had an improvement in contrast sensitivity (that) was statistically significant,” Dr. Slade said. He said no other clinical study he is aware of has demonstrated a statistically significant improvement in contrast sensitivity by 2 units of measurement.

Improvement in contrast sensitivity can significantly improve a patient’s night vision, Dr. Slade said.

“Patients are able to see lighter contrasts. They can see things that they didn’t see before in a variety of low light settings,” he explained.

According to Dr. Slade, contrast sensitivity correlates with aberrations in the eye. “Contrast sensitivity is one of the best measurements we have to determine the practical effect of aberrations on the eye,” he said. “For instance, we will be able to objectively grade what 0.1 µm of spherical aberration means. Contrast sensitivity can show you how much aberration exists in a patient’s eye.”

For Your Information:

• Daniel S. Durrie, MD, can be reached at Durrie Vision, 5520 College Blvd., Suite 200, Overland Park, KS 66211; (913) 491-3737; fax: (913) 491-9650; e-mail: ddurrie@hunkeler.com.
• Stephen G. Slade, MD, can be reached at 3900 Essex Lane, Suite 101, Houston, TX 77027; (713) 626-5544; fax: (713) 626-7744; e-mail: stephen_slade@bausch.com.
• Colman R. Kraff, MD, can be reached at Kraff Eye Institute, 25 E. Washington, Suite 606, Chicago, IL 60602; (312) 444-1111; (312) 444-1953; e-mail: c.kraff@ix.netcom.com. Dr. Kraff is a paid consultant for Visx. He has no direct financial interest in the products discussed in this article.

• Alcon, manufacturer of CustomCornea, can be reached at 6201 South Freeway, Fort Worth, TX 76134; (817) 293-0450; fax: (817) 568-6142.
• Bausch & Lomb, manufacturer of Zyoptix, can be reached at 1400 N. Goodman St., Rochester, NY 14609; (585) 338-5212; fax: (585) 338-0898; Web site: www.bausch.com. Visx Inc., manufacturer of CustomVue, can be reached at 3400 Central Expressway, Santa Clara, CA 95051-7122; (408) 733-2020; fax: (408) 773-7278.