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MOST patients who undergo cataract surgery under peribulbar anaesthesia experience a sometimes frightening array of visual hallucinations, Hungarian researchers report. "Our research indicates that a majority of cataract patients see lights that change in intensity, different colours, and even surgical instruments, which at times can make them very uncomfortable," Zsolt Biró MD told a session of the annual congress of the German-speaking Association for Intraocular Lens Implantation and Refractive Surgery (DGII). He conducted a study to ascertain whether cataract patients experience visual sensations during phaco and IOL implantation performed under peribulbar anaesthesia, and what the nature of these sensations might be. He interviewed 164 patients within the first hour following standard phaco and IOL implantation. Patients ranged in age from 34 to 90 years. Sixty participants (37%) had other ophthalmic pathologies, including glaucoma, diabetic retinopathy, AMD or myopia. Some 58% of the patients underwent first eye surgery while the remainder underwent second eye surgery. The preoperative treatment consisted of a mild sedative (one tablet 0.25mg Xanax) and pupillary dilation. The researchers administered one drop of 10% Neosynephrine and 4% Humacaine (oxybuprocaine). Standard peribulbar anaesthesia followed, which included 2.5ml of 0.2% Naropine (ropivacaine) and 1.5ml of 10% Lidocaine. The surgeons then applied 10 minutes of oculocompression. Thirty-two patients (19.5%) had no light perception at all during surgery. By contrast, 132 (80.5%) reported various visual sensations at some point during the cataract surgery. All of those who experienced visual sensations saw lights of different and changing intensities. Sixteen of the patients in the study considered the strong microscope light very disturbing and uncomfortable. Some 88% of the study participants saw different colours. The most commonly experienced colours, in descending order of incidence, were grey-black, yellow, red, and blue, followed by pink, white, green, violet and brown. A few patients reported seeing a rainbow-like scale of colours. Half the study participants reported seeing clear shapes and forms, mostly consisting of basic shapes, such as circles, squares, triangles, rectangles and ellipses. Others reported seeing shapes within other shapes and shadowy borders. Eighteen of the patients reported seeing surgical instruments. Nine other reported seeing images of the surgeon’s fingers. Five participants said they considered the surgery in general to be a very uncomfortable experience. Seventeen patients were asked to draw representations of their visual experiences. These were shown to the last 71 patients of the study group to prepare them for what was to come. According to Dr Biró, patient awareness may well be the component that counted most towards patient satisfaction. He said the group shown the drawings of possible visual sensations experienced during surgery was less anxious during surgery than the unprepared group. "It would be advantageous to inform the cataract patient of potential intraoperative visual sensations prior to surgery in order to reduce patient anxiety," he suggested. Dr K Eong and his team in Singapore reported similar experiences in a 1999 study which followed 100 cataract patients who underwent retrobulbar anaesthesia. While 20 patients saw nothing when questioned directly after surgery, the other 80 participants experienced colours, movements, flashes, instruments and hands, in that order. Some 5% were quite frightened by the experience. A common finding in both studies was the lack of any relationship between the intraoperative visual sensations and the patient age, sex, preoperative visual acuity, concomitant ocular pathology, first or second eye surgery or cataract severity. Zsolt Biró MD Medical University of Pécs, Hungary Email: zsolt.biro@ako.pte.hu or phaco@clinics.pote.hu
Zsolt Biró MD |
