March 2008




Strong visual sensations

by Rich Daly EyeWorld Contributing Editor



Surgeons should warn patients about “frightening” images that they are likely to experience

The great majority of vitrectomy patients experience powerful and sometimes frightening images during surgery, according to a recent study.

The little-studied area of vitrectomy surgery, compared to cataract surgery, examined visual sensations during vitrectomy, and the findings concerned the authors. They urge surgeons to discuss potential images with patients pre-op.

Eiko Sugisaka, M.D., and colleagues at Keio University School of Medicine questioned 56 men and 45 women, 30 to 89 years old, about their experiences during pars plana vitrectomy performed using 2% lidocaine hydrochloride. The study was recently published in the American Journal of Ophthalmology.1 The patients were interviewed during surgery and within three hours after the vitrectomy about their visual experiences during the procedure.

Ninety-one of the 101 patients in the study experienced some type of visual sensation during vitrectomy, including lights (90%), colors (73%) and movements (56%), including the instruments and the surgeons’ hands. In the 94 cases that had triamcinolone-assisted vitrectomy, 35 (37.2%) reported seeing “diffuse whirling black spots” and six patients (5.9%) found the visual experiences frightening.

The number who reported being frightened was similar to those in other studies who retained visual sensations during cataract surgery, which ranged from 3 to 15% in the research cited by the authors.

The study authors asked patients similar questions about their visual sensations during different phases of the 30 minutes of surgery and in the three hours after surgery. Patients were also asked to rate their pain during surgery. “The dialogue with the patient was almost continuous during the different phases of vitrectomy, and continuous reassurances were given that everything was proceeding nicely,” wrote the authors.

The study found no obvious correlations between the different types of sensations for patients with different vitreoretinal pathologic features. Pain scores from 90 patients indicated most (62 patients) had none, and no significant correlation was found between the number of the patients with no visual sensations and the pain score. However, eyes with poor macular function, such as those with rhegmatogenous retinal detachment with macular involvement, submacular hemorrhage, or macular hole, were less likely to experience clear visual sensations.

Another significant correlation was found between the pre-op or post-op visual acuity and intra-operative visual sensation. The authors noted that the findings cannot be expanded directly to mean the intra-operative visual sensation may predict post-op visual acuity; however, patients who reported intra-operative sensation for light as well as colors or moving objects—which are perceived mainly by the cone system—showed significantly better post-op visual acuity.

“This suggests that the intraoperative visual sensation is highly correlated with the macular function of the patient,” they wrote.

The number of patients reporting the various visual sensations appeared unaffected by the amount of anesthesia, gender, age, and pain. The six patients who reported “frightening” visual experiences had no distinct distribution by age or gender, although they did have lower amounts of anesthesia. “Interestingly, the pain score also was lower in these six patients,” wrote the authors. The findings led the authors to recommend pre-op counseling including information about the possibility of intra-op visual sensations that may be experienced.

Jimmy Lai, M.D., United Christian Hospital, Kowloon, Hong Kong, who authored a 2004 study in the Journal of Cataract and Refractive Surgery on visual sensations during cataract surgery using topical and regional anesthesia, agreed on the need for pre-op counseling about the possibility of intra-op visual sensations. However, he does not greatly emphasize such warnings.

“It’s good for patients to be informed of such sensations, but it is not crucial for a good surgical outcome,” he said.

The study results confirmed for the authors that some intra-op communication with patients may help to avoid upsetting patients and help them feel assured.

Dr. Lai agreed that patients should be informed of progress of the operation from “time to time.” He noted that although visual sensations may be frightening to some patients, audio sensation also is important. “I never speak of things like my dissatisfaction with the progress of the surgery or difficulty of the surgery during operation,” Dr. Lai said. “This will cause unnecessary anxiety to patients.”

Dr. Lai added that his clinical experience does not reflect the authors’ assertion that visual sensations during surgery are important determinants of patient satisfaction with any anesthetic technique.

Editors’ note: Dr. Lai has no financial interests related to his comments.

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1. Sugisaka K, Shinoda S, Ishida Y, et al. Patients’ descriptions of visual sensations during pars plana vitrectomy under retrobulbar anesthesia. Am J. of Ophthal. 2007; 144 (2):245-251.

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