Conscious sedation during ophthalmic surgery under local anesthesia.

Sedation during ophthalmic local anesthesia helps to ensure comfort and cooperation during eye surgery. Sedation requirements of ophthalmic patients have changed with the popularization of newer surgical and anesthetic techniques. Many sedative agents are available to anesthesiologists including benzodiazepines, intravenous anesthetic induction agents, narcotic analgesics and a-adrenoreceptor agonists. However, there is no single ideal sedative agent, regime or protocol that can completely cater to the wide spectrum of ophthalmic procedures performed in a heterogeneous patient population. Moreover, the clinical practice of sedation during ophthalmic surgery under local anesthesia is varied and not without risk of complications and adverse events. Hence, balanced sedative techniques should only be used after careful consideration of patient profile, the type of eye surgery, and patient and surgeon preferences. Good knowledge of the pharmacology of sedative agents is fundamental to their useful clinical application.

Knowledge of visual experience during cataract surgery under local anaesthesia: a nationwide survey of UK ophthalmologists.

AIM: To evaluate the knowledge and practices of UK ophthalmologists regarding patients' subjective visual experience during cataract surgery under local anaesthesia. METHODS: A nationwide postal survey was conducted on UK ophthalmologists using a standardised questionnaire. RESULTS: The proportion of surgeons who operated under regional anaesthesia who thought that patients could experience the following visual sensations were: no light perception (54%); light perception (95%); one or more colours (93%); flashes of light (81%); movement (87%); instruments (61%); surgeon's hands or fingers (53%); surgeon (43%); and changes in light brightness (88%). Fifty-eight per cent of them thought that patients might be frightened by this, and 77% thought that preoperative counselling could help alleviate this fear. The proportion of surgeons who operated under topical anaesthesia who thought that patients could experience the following visual sensations were: no light perception (10%); light perception (94%); one or more colours (97%); flashes of light (86%); movement (96%); instruments (81%); surgeon's hands or fingers (65%); surgeon (51%); changes in light brightness (95%). Fifty-nine per cent of them thought that patients might be frightened by this, and 80% thought that preoperative counselling could help alleviate this fear. CONCLUSION: Most UK surgeons believed that during cataract surgery under local anaesthesia, patients might experience various visual sensations which could cause fear and that such fear could be alleviated by preoperative counselling.

Practice preferences of ophthalmic anaesthesia for cataract surgery in Singapore.

INTRODUCTION: This study aims to describe the preferences of ophthalmic anaesthesia for cataract extraction among ophthalmologists in Singapore. METHODS: A nationwide questionnaire survey of all cataract surgeons in institutional and private practice in Singapore was conducted in August 2004. RESULTS: The response rate was 61.1 percent (88 out of 144 eligible ophthalmologists surveyed). Phacoemulsification was the preferred surgical technique for 92 percent of the respondents while extra-capsular cataract extraction was preferred by eight percent. For all surgeons performing phacoemulsification, the anaesthesia technique of choice was peribulbar anaesthesia for 43 percent, topical anaesthesia for 42 percent, retrobulbar anaesthesia for 13 percent, and sub-tenons and general anaesthesia for one percent each of the respondents. For all the surgeons performing extra-capsular cataract extraction, the preferred anaesthetic technique was peribulbar anaesthesia for 69 percent, retrobulbar anaesthesia for 30 percent and sub-tenons anaesthesia for one percent of the respondents. The surgeons' main reasons for choosing a specific anaesthesia modality for their surgery were patient comfort and surgeon's choice. The majority of surgeons used mild sedation and monitored anaesthesia care for their cataract surgeries. CONCLUSION: Peribulbar anaesthesia is currently the preferred anaesthesia technique for both phacoemulsification and extra-capsular cataract extraction in Singapore. Topical anaesthesia closely follows peribulbar anaesthesia as a preferred choice for phacoemulsification.

Patients' expectation and experience of visual sensations during phacoemulsification under topical anaesthesia.

PURPOSE: To describe what patients expect to see and the visual sensations they actually experience during phacoemulsification under topical anaesthesia. We also sought to determine if patients find their intraoperative visual experience frightening and the factors associated with this. MATERIALS AND METHODS: Ninety-eight patients who underwent phacoemulsification and intraocular lens implantation under topical anaesthesia were interviewed preoperatively on what they expected to see with their operated eye during surgery and again postoperatively on what they actually saw. No patient received counselling about possible intraoperative visual sensations. A logistic (multivariate) regression model was used for statistical analysis. RESULTS: Preoperatively, 36 patients (36.7%) expected at least light perception, 38 (38.8%) expected no light perception, and 24 (24.5%) were unsure what to expect. Some patients also expected a variety of different visual sensations. Postoperatively, all patients (100%) reported seeing light intraoperatively and many experienced various other visual sensations. Nineteen patients (19.4%) found their visual experience frightening. The following factors were statistically associated with a frightening visual experience: preoperative anxiety, previous cataract surgery in the fellow eye, experiencing an intraoperative increase in clarity, not seeing movement intraoperatively, and not knowing what to expect. CONCLUSIONS: The majority of patients in this study either expected that they would see nothing at all during the surgery or were unsure of what to expect. All patients subsequently saw at least some light, and many perceived various other visual sensations that were frightening to nearly one in five patients. Preoperative counselling should inform about possible intraoperative visual experience.

Visually significant opacification of hydrophilic acrylic intraocular lenses--a clinico-pathological analysis.

PURPOSE: To describe the clinic-pathological analysis of the visually significant opacification of the Cirrus International Hydroflex foldable hydrophilic acrylic intraocular lens (IOL) (model SC600-2, Medical Developmental Research Inc., Clearwater, Florida) and to highlight that this IOL is the same model as the Acryflex SC600-2 IOL, by the same manufacturer. METHODS: Retrospective review of five eyes of four patients with opacification of their Cirrus International Hydroflex foldable hydrophilic acrylic IOLs (model SC600-2) after uncomplicated phacoemulsification and IOL implantation. Two IOLs were explanted from two patients 14 to 24 months after initial implantation. Each explanted lens was divided into equal halves, one half for scanning electron microscopy (SEM) study and the other half for transmission electron microscopy (TEM) examination. SEM and TEM samples were also subjected to energy dispersive X-ray analysis (EDX). RESULTS: The IOL opacification was detected 14 to 24 months after uncomplicated phacoemulsification and IOL implantation. EDX analysis showed that the crystals contained calcium and phosphorus, presumably calcium phosphate. CONCLUSIONS: The Cirrus International Hydroflex foldable hydrophilic acrylic IOL (model SC600-2) is associated with opacification, that appeared worse centrally than peripherally. This is the same model as the Acryflex SC600-2 IOL, made by the same manufacturer. The opacification consists of calcium and phosphate.

6th Yahya Cohen Lecture: visual experience during cataract surgery.

INTRODUCTION: The visual sensations many patients experience during cataract surgery under local anaesthesia have received little attention until recently. This paper reviews the recent studies on this phenomenon, discusses its clinical significance and suggests novel approaches to reduce its negative impact on the surgery. METHODS: Literature review. RESULTS: Many patients who have cataract surgery under retrobulbar, peribulbar or topical anaesthesia experience a variety of visual sensations in their operated eye during surgery. These visual sensations include perception of light, movements, flashes, one or more colours, surgical instruments, the surgeon's hand/fingers, the surgeon and changes in light brightness. Some patients experience transient no light perception, even if the operation is performed under topical anaesthesia. The clinical significance of this phenomenon lies in the fact that approximately 7.1% to 15.4% of patients find their visual experience frightening. This fear and anxiety may cause some patients to become uncooperative during surgery and trigger a sympathetic surge, causing such undesirable effects as hypertension, tachycardia, ischaemic strain on the heart, hyperventilation and acute panic attack. Several approaches to reduce the negative impact of patients' visual experience are suggested, including appropriate preoperative counselling and reducing the ability of patients to see during surgery. CONCLUSIONS: The findings that some patients find their intraoperative visual experience distressing have a major impact on the way ophthalmologists manage their cataract patients. To reduce its negative impact, surgeons should consider incorporating appropriate preoperative counselling on potential intraoperative visual experience when obtaining informed consent for surgery.

Myopia: attempts to arrest progression.

Previous studies have evaluated the efficacy of several interventions to decrease the progression of myopia. These include devices that alter the perception of the visual environment and pharmacological treatments. There is no conclusive evidence thus far that alteration of the pattern of spectacle wear, bifocals, ocular hypotensives, or contact lenses retards the progression of myopia. Several randomised clinical trials have demonstrated that the rate of progression of myopia is lower in children given atropine eye drops than those given placebo. However, atropine is associated with short term side effects such as photophobia and possible long term adverse events including light induced retinal damage and cataract formation. Other more selective antimuscarinic agents such as pirenzipine are presently being evaluated. Further well conducted randomised clinical trials with large sample sizes and adequate follow up designed to evaluate treatments to retard the progression of myopia should be conducted, since the identification of an effective intervention may have a greater public health impact on the burden and morbidity from myopia than the few treatments currently available.

Subjective visual experience during phacoemulsification and intraocular lens implantation using retrobulbar anesthesia.

PURPOSE: To investigate the subjective visual experience of patients during phacoemulsification and intraocular lens (IOL) implantation using retrobulbar anesthesia. SETTING: Department of Ophthalmology, Tan Tock Seng Hospital, Singapore. METHODS: Seventy cataract patients who had routine phacoemulsification and posterior chamber IOL implantation under retrobulbar anesthesia were interviewed on the day of their surgery regarding their visual experience in the operated eye during surgery. Thirty-nine men (55.7%) and 31 women (44.3%) were included in the study. Their mean age was 65.1 years (range 37 to 87 years). Preoperative best corrected visual acuity ranged from 6/12 to counting fingers. Sixty eyes (85.7%) had no ocular pathology other than cataract. Eleven patients (15.7%) reported no light perception during the surgery. The rest reported they could see light (59 patients, 84.3%), 1 or more colors (39 patients, 55.7%), flashes (35 patients, 50.0%), movements (34 patients, 48.6%), instruments (12 patients, 17.1%), and the surgeon's fingers or hands (11 patients, 15.7%). The colors seen included red (23 patients, 32.9%), blue (17 patients, 24.3%), yellow (12 patients, 17.1%), green (7 patients, 10. 0%), and orange (1 patient, 1.4%). Eight patients (11.4%) saw a spectrum of colors similar to a rainbow. Thirty-one patients (44.3%) reported that the brightness of light changed during surgery. Five patients (7.1%) found their visual experience frightening. Patients who reported seeing colors (P =.048, Fisher exact test) and flashes of light (P =.027, Fisher exact test) were more likely to find the experience frightening. There was no statistically significant correlation between those who found the experience frightening and patient sex or age, length of surgery, or history of cataract surgery in the fellow eye. CONCLUSIONS: Many patients having phacoemulsification and IOL implantation under retrobulbar anesthesia experienced a variety of visual sensations that were frightening in a small proportion of cases.

Subjective visual experience during phacoemulsification and intraocular lens implantation under topical anesthesia.

OBJECTIVE: The aim of this study was to investigate the subjective visual experience of patients during phacoemulsification and intraocular lens (IOL) implantation under topical anesthesia. DESIGN: Postoperative questionnaire survey. PARTICIPANTS: The study cohort consisted of 52 patients with cataracts. There were 18 male (34.6%) and 34 female (65.4%) patients. Their mean (+/- SD) age was 67.5 (+/-10.8) years. INTERVENTION: The patients underwent routine phacoemulsification and IOL implantation under topical anesthesia. MAIN OUTCOME MEASURES: The patients were interviewed on the same day after their operation regarding their visual experience in the operated eye during surgery. RESULTS: All patients (100%) reported that they could see at least some light during the surgery. Some patients reported they could also see one or more colors (50 patients, 96.2%), movements (32 patients, 61.5%), flashes (24 patients, 46.2%), the surgeon's fingers/hands (13 patients, 25%), instruments (12 patients, 23.1%), and/or the surgeon (4 patients, 7.7%). The colors seen included red (24 patients, 46.2%), yellow (23 patients, 44.2%), blue (12 patients, 23.1%), green (7 patients, 13.5%), and orange (6 patients, 11.5%). Eight patients (15.4%) saw the spectrum of colors similar to that of the rainbow. Twenty-four patients (46.2%) reported that the brightness of light changed during the course of the operation. Eight patients (15.4%) found their visual experience frightening. There was no statistically significant association between those who found the visual experience frightening and the sex or age of the patient, a history of cataract operation in the fellow eye, the type of visual sensation experienced, or the presence of coexisting ocular pathology. CONCLUSION: All patients undergoing phacoemulsification under topical anesthesia experience a variety of visual sensations that may be frightening in a small proportion of patients.

Subjective visual experience during extracapsular cataract extraction and intraocular lens implantation under retrobulbar anaesthesia.

PURPOSE: To investigate the subjective visual experience of patients during cataract surgery under retrobulbar anaesthesia. METHODS: One hundred cataract patients who underwent routine extracapsular cataract extraction and intraocular lens implantation under retrobulbar anaesthesia were interviewed by the authors on the same day after their operation regarding their visual experience in the operated eye during surgery. RESULTS: Forty-three men and 57 women were included in the study. Their mean age was 68.4 years (range 40-87 years). Their pre-operative best corrected visual acuity ranged from 6/12 to perception of light. Eighty-four eyes had no other ocular pathology apart from cataract. Twenty patients reported no light perception during the surgery. The rest reported that they could see light (80 patients), one or more colours (56 patients), movements (39 patients), flashes (36 patients), instruments (16 patients) and/or the surgeon's fingers or hands (10 patients). The colours seen included red (29 patients), yellow (29 patients), green (12 patients), blue (11 patients) and orange (2 patients). Fifteen patients saw a spectrum of colours similar to that of the rainbow. Forty-four patients reported that the brightness of light changed during the operation. Five patients found their visual experience frightening. There was no correlation between those who found the experience frightening and the sex or age of patient, presence of coexisting ocular pathology, duration of operation, whether the operation was the first or second cataract operation in the patient, or the type of visual sensation experienced. CONCLUSION: Many patients undergoing cataract surgery under retrobulbar anaesthesia experience a variety of visual sensations that may be frightening in a small proportion of cases.