Comparison of cycloplegia at 20- and 30-minutes following proxymetacaine and cyclopentolate instillation in white 12-13-year-olds

CLINICAL RELEVANCE

Reducing the time between drop instillation and refraction reduces the time paediatric patients and young adults spend in practice, facilitating more eye examinations daily.

BACKGROUND

The current procedure for paediatric cycloplegic refraction is to wait for at least 30-minutes post-instillation of a cycloplegic before measuring spherical equivalent refraction. This study compared cycloplegia at 20- and 30-minutes following 0.5% proxymetacaine and 1.0% cyclopentolate in 12-13-year-olds.

METHODS

Participants were 99 white 12-13-year-olds. One drop of proxymetacaine hydrochloride (Minims, 0.5% w/v, Bausch & Lomb, UK) followed by one drop of cyclopentolate hydrochloride (Minims, 1.0% w/v, Bausch & Lomb, UK) was instilled into both eyes. Spherical equivalent refraction was measured by autorefraction (Dong Yang Rekto ORK-11 Auto Ref-Keratometer) at 20- and 30-minutes post-instillation. Data were analysed through paired t-testing, correlations, and linear regression analysis.

RESULTS

There was no significant difference in level of cycloplegia achieved at 20- (Mean spherical equivalent refraction (standard deviation) 0.438 (1.404) D) and 30-minutes (0.487 (1.420) D) post-eyedrop instillation (t (98) = 1.667, p = 0.099). The mean spherical equivalent refraction difference between time points was small (0.049 (0.294) D, 95% confidence interval =-0.108 ̶ 0.009D). Agreement indices: Accuracy = 0.999, Precision = 0.973, Concordance = 0.972. Spherical equivalent refraction at 20- and 30-minutes differed by ≤0.50D in 92% of eyes, and by <1.00D in 95%.

CONCLUSIONS

There was no clinically significant difference in spherical equivalent refraction or level of cycloplegia at 20- and 30-minutes post-eyedrop instillation. The latent time between drop instillation and measurement of refractive error may be reduced to 20 minutes in White 12-13-year-olds and young adults. Further studies must determine if these results persist in younger children and non-White populations.

New application of an old drug proparacaine in treating epilepsy via liposomal hydrogel formulation

Proparacaine (PPC) is a previously discovered topical anesthetic for ophthalmic optometry and surgery by blocking the central Nav1.3. In this study, we found that proparacaine hydrochloride (PPC-HCl) exerted an acute robust antiepileptic effect in pilocarpine-induced epilepsy mice. More importantly, chronic treatment with PPC-HCl totally terminated spontaneous recurrent seizure occurrence without significant toxicity. Chronic treatment with PPC-HCl did not cause obvious cytotoxicity, neuropsychiatric adverse effects, hepatotoxicity, cardiotoxicity, and even genotoxicity that evaluated by whole genome-scale transcriptomic analyses. Only when in a high dose (50 mg/kg), the QRS interval measured by electrocardiography was slightly prolonged, which was similar to the impact of levetiracetam. Nevertheless, to overcome this potential issue, we adopt a liposome encapsulation strategy that could alleviate cardiotoxicity and prepared a type of hydrogel containing PPC-HCl for sustained release. Implantation of thermosensitive chitosan-based hydrogel containing liposomal PPC-HCl into the subcutaneous tissue exerted immediate and long-lasting remission from spontaneous recurrent seizure in epileptic mice without affecting QRS interval. Therefore, this new liposomal hydrogel formulation of proparacaine could be developed as a transdermal patch for treating epilepsy, avoiding the severe toxicity after chronic treatment with current antiepileptic drugs in clinic.

REPLACEMENT OF LIDOCAINE GEL WITH TOPICAL PROPARACAINE ANESTHESIA FOR ROUTINE INTRAVITREAL INJECTIONS: A Comparative Study

PURPOSE

Lidocaine gel was suggested to be highly effective in providing anesthesia for intravitreal injections but adverse effects include a possibility of making sterilization of the conjunctiva difficult. Hence, we wished to determine the effect of using 0.5% proparacaine drops alone over the use of 3.5% lidocaine hydrochloride gel anesthesia during office-based intravitreal injections.

METHODOLOGY

This was a case-control study in patients who came routinely to the clinic for antivascular endothelial growth factor injections. Eyes were treated with one of two anesthesia modalities. A total of 216 injections in 120 patients were reviewed. One group (N = 107) underwent anesthesia with 0.5% proparacaine drops, and the control group (N = 109) received 3.5% lidocaine gel. The pain perceived after injection was graded using the numerical rating scale, and score was immediately recorded by the "masked" injecting physician.

RESULTS

The mean pain score (±SD) for the proparacaine-only group versus gel group was 1.97 (±1.17) versus 1.76 (±0.92), P value = 0.3174. There was no statistical difference between the 2 groups.

CONCLUSION

3.5% lidocaine gel is not superior to 0.5% proparacaine drops as patients attained good pain control and excellent rates of overall satisfaction with proparacaine drops alone.

Postoperative Corneal Injuries: Incidence and Risk Factors

BACKGROUND

Previous studies of postoperative corneal injury rates relied on provider-initiated incident reports, which may underestimate the true incidence. Postoperative administration of proparacaine eye drops is used almost exclusively to diagnose corneal injury; therefore, identifying instances of administration may provide a better estimate of corneal injuries. We compared proparacaine administration versus provider-initiated reports to determine rates of corneal injury. In addition, potential associations between clinical variables and injury were assessed with a matched case-control study.

METHODS

The health records of 132,511 sequential adult postanesthesia recovery room admissions (January 1, 2011 to June 30, 2017) were reviewed to identify postoperative proparacaine administration and incident reports of corneal injury. Patients with corneal injury were matched with control patients at a 1:2 ratio to assess factors associated with injury.

RESULTS

Proparacaine drops were administered to 442 patients (425 patients received proparacaine for diagnosis and 17 patients received proparacaine for unrelated reasons). Incident reports identified 320 injuries, and the aggregate corneal injury count was 436 (incidence, 3.3 injuries [95% confidence interval {CI}, 3.0-3.6] per 1000 cases of general anesthesia). Proparacaine administration had a greater case ascertainment percentage than incident reporting (97.5% vs 73.4%; P < .001). The matched case-control analysis found greater risks associated with longer duration of anesthesia (odds ratio, 1.05 [95% CI, 1.03-1.07] per 10 minutes of anesthesia; P < .001) and nonsupine surgical position (odds ratio, 3.89 [95% CI, 2.17-6.98]; P < .001). Patients with injuries also had more evidence of sedation and agitation during anesthesia recovery.

CONCLUSIONS

Calculation of incidence by using the administration of a medication (proparacaine eye drops) that is almost exclusively used to diagnose a specific injury (corneal injury) showed higher case ascertainment percentage than incident-reporting methods. Similar strategies could be used to monitor the rates of other adverse events.

Serotonin enhances oxybuprocaine- and proxymetacaine-induced cutaneous analgesia in rats

The aim of the study was to investigate the analgesic effects of adding serotonin to oxybuprocaine or proxymetacaine preparations. We employed a rat model of the cutaneous trunci muscle reflex (CTMR) to conduct the dose-response curves and duration of drugs (oxybuprocaine, proxymetacaine, or serotonin) as an infiltrative anesthetic. The use of isobolographic methods to analyze the drug-drug interactions. We showed that oxybuprocaine and proxymetacaine, as well as serotonin produced dose-dependent skin antinociception. On the basis of 50% effective dose (ED₅₀), the rank order of drug potency was serotonin [7.22 (6.45-8.09) μmol/kg] < oxybuprocaine [1.03 (0.93-1.15) μmol/kg] < proxymetacaine [0.59 (0.53-0.66) μmol/kg] (P < 0.01 for each comparison). The sensory block duration of serotonin was longer (P < 0.01) than that of oxybuprocaine or proxymetacaine at the equipotent doses (ED₂₅, ED₅₀, and ED₇₅). The mixture of serotonin with oxybuprocaine or proxymetacaine produced a better analgesic effect than the drug itself. We have concluded that oxybuprocaine, proxymetacaine, or serotonin displays dose-related cutaneous analgesia. Oxybuprocaine or proxymetacaine is more potent and has a shorter duration of cutaneous analgesia than serotonin. Serotonin produces a synergistic antinociceptive interaction with oxybuprocaine or proxymetacaine.

Adding Dopamine to Proxymetacaine or Oxybuprocaine Solutions Potentiates and Prolongs the Cutaneous Antinociception in Rats

BACKGROUND

We evaluated the interaction of dopamine-proxymetacaine and dopamine- oxybuprocaine antinociception using isobolograms.

METHODS

This experiment uses subcutaneous drug (proxymetacaine, oxybuprocaine, and dopamine) injections under the skin of the rat's back, thus simulating infiltration blocks. The dose-related antinociceptive curves of proxymetacaine and oxybuprocaine alone and in combination with dopamine were constructed, and then the antinociceptive interactions between the local anesthetic and dopamine were analyzed using isobolograms.

RESULTS

Subcutaneous proxymetacaine, oxybuprocaine, and dopamine produced a sensory block to local skin pinpricks in a dose-dependent fashion. The rank order of potency was proxymetacaine (0.57 [0.52-0.63] μmol/kg) > oxybuprocaine (1.05 [0.96-1.15] μmol/kg) > dopamine (165 [154-177] μmol/kg; P < .01 for each comparison) based on the 50% effective dose values. On the equianesthetic basis (25% effective dose, 50% effective dose, and 75% effective dose), the nociceptive block duration of proxymetacaine or oxybuprocaine was shorter than that of dopamine (P < .01). Oxybuprocaine or proxymetacaine coinjected with dopamine elicited a synergistic antinociceptive effect and extended the duration of action.

CONCLUSIONS

Oxybuprocaine and proxymetacaine had a higher potency and provoked a shorter duration of sensory block compared with dopamine. The use of dopamine increased the quality and duration of skin antinociception caused by oxybuprocaine and proxymetacaine.

The Addition of Epinephrine to Proxymetacaine or Oxybuprocaine Solution Increases the Depth and Duration of Cutaneous Analgesia in Rats

BACKGROUND

The aim of this experiment was to investigate the interaction between epinephrine and 2 local anesthetics (proxymetacaine or oxybuprocaine) using subcutaneous injections under the hairy skin, thereby simulating infiltration blocks.

METHODS

Using a rat model of cutaneous trunci muscle reflex in response to local skin pinpricks, the anesthetic properties of proxymetacaine and oxybuprocaine alone and in combination with epinephrine as an infiltrative anesthetic were tested. Isobolographic analysis was used for the analgesic interactions between adjuvant epinephrine and the local anesthetics. Lidocaine was used as a control group.

RESULTS

Oxybuprocaine, proxymetacaine, and lidocaine elicited a dose-dependent block to pinpricks. On the 50% effective dose (ED50) basis, their relative potencies were proxymetacaine [0.126 (0.113-0.141) μmol] greater than oxybuprocaine [0.208 (0.192-0.226) μmol] greater than lidocaine [6.331 (5.662-7.079) μmol] (P < 0.01 for each comparison). On an equipotent basis (ED25, ED50, and ED75), sensory block duration elicited by oxybuprocaine or proxymetacaine was greater than that elicited by lidocaine (P < 0.01). Coadministration of proxymetacaine, oxybuprocaine, or lidocaine with epinephrine produced a synergistic analgesic effect and prolonged the cutaneous analgesic effect. After adding epinephrine, oxybuprocaine was much faster, reaching its maximal blockade, than proxymetacaine or lidocaine (P < 0.01).

CONCLUSIONS

We concluded that proxymetacaine and oxybuprocaine were more potent and produced greater duration of nociceptive block than lidocaine. The use of epinephrine augmented the potency and prolonged the duration of proxymetacaine, oxybuprocaine, and lidocaine as an infiltrative anesthetic.

Efficacy of Single Dose Oral Paracetamol in Reducing Pain During Examination for Retinopathy of Prematurity: A Blinded Randomized Controlled Trial

OBJECTIVE

To investigate the efficacy of paracetamol in reducing pain during examination for retinopathy of prematurity (ROP) in preterm infants.

METHODS

A total of 114 infants undergoing eye examination for retinopathy of prematurity screening were prospectively randomized. Topical anesthetic (Proparacaine; Alcaine® drop 0.5%) was applied 30 s before the eye examination in all the infants. The infants in the intervention group (Group 1, n = 58) received 15 mg/kg of oral paracetamol, 60 min before the examination. The control group (Group 2, n = 56) received the same volume of sterile water per oral with an opaque syringe. Primary outcome measurement was pain assessed by Premature Infant Pain Profile (PIPP) score. Secondary outcome measurements were tachycardia (>180 bpm)/bradycardia (<100 bpm), desaturations (<85% for >10 s), and crying time.

RESULTS

The groups were similar for gestational age, birthweight or postnatal age at examination. The intervention group had a significantly lower mean PIPP score during eye examination, following insertion of the speculum [Group 1:12 (9-13) vs. Group 2:14 (13-15), p 0.001]. There were no significant differences between the groups with regard to crying time and the number of the patients with tachycardia/bradycardia and desaturation.

CONCLUSIONS

Oral paracetamol modestly reduces pain scores during eye examinations. Further cross-over trials on dose and frequency of paracetamol and combination of pharmacological with non-pharmacological approaches and paracetamol alone as a single agent in significant pain reduction are needed.

Randomized double-masked controlled trial comparing pain scores with and without the use of supplementary 2% lidocaine gel in LASIK

PURPOSE

To compare pain scores with and without supplementary topical 2% lidocaine gel in patients undergoing simultaneous bilateral laser-assisted in situ keratomileusis (LASIK) under topical anesthesia using 0.5% proparacaine eye drops.

DESIGN

Randomized double-masked placebo-controlled trial.

METHODS

Fifty-one Chinese subjects (102 eyes, with 51 eyes in each arm) were included. One eye was randomly allocated to have supplementary 2% lidocaine gel while the other eye received carbomer gel as control, in addition to topical 0.5% proparacaine. The pain scores for each eye during microkeratome flap creation, during laser ablation, and at 15, 30, and 45 minutes after LASIK were assessed. An overall pain score of the LASIK procedure was also obtained. Primary outcome measures were pain scores during and after LASIK. Secondary outcomes included need for additional topical anesthesia, patient cooperation score, and duration and complications of surgery.

RESULTS

In the 2% lidocaine gel-treated group, the pain scores were significantly lower during microkeratome flap creation and laser ablation, and postoperatively at 30 and 45 minutes (P<.05 for all). Patients in the lidocaine gel group required less additional topical anesthesia (P=.0004) and were more cooperative (P=.019) as compared to the carbomer gel group. No surgical or postoperative complications were observed.

CONCLUSIONS

The use of supplementary 2% lidocaine gel in LASIK is effective in lowering the pain experienced during and up to 45 minutes after LASIK.

Local anaesthetic eye drops for prevention of pain in preterm infants undergoing screening for retinopathy of prematurity

BACKGROUND

Screening examinations for retinopathy of prematurity (ROP) are performed routinely in the neonatal intensive care unit and are a recognised cause of pain in the newborn.

OBJECTIVES

To determine the effect of instillation of topical anaesthetic eye drops compared with placebo or no treatment on pain in infants undergoing ROP screening.

SEARCH STRATEGY

We used the standard search strategy of the Cochrane Neonatal Review Group. This included a search of the Cochrane Neonatal Group register and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 10, 2010). We identified relevant studies by searching the following: (1) computerised bibliographic databases: MEDLINE (1966 to October 2010), EMBASE (1988 to October 2010) and Web of Science (1975 to March 2010; (2) the Oxford Database of Perinatal Trials. We searched electronically abstracts from PAS from 2000 to 2010 and handsearched abstracts from ESPR from 2000 to 2009.

SELECTION CRITERIA

All randomised, or quasi-randomised controlled trials, or randomised cross-over trials.

DATA COLLECTION AND ANALYSIS

We used the standard methods of the Cochrane Neonatal Review Group.

MAIN RESULTS

We identified two studies for inclusion. Both studies were randomised cross-over trials performed in single centres. Both studies used the Premature Infant Pain Profile (PIPP) score as a measure of pain response. Different methods of evaluating PIPP scores are presented including the absolute PIPP score, a PIPP score > 10 or > 12 and an increase in PIPP ≥ 4 from the baseline value. There is a nonsignificant reduction in pain scores at one minute and a nonsignificant increase at five minutes post insertion of the speculum. PIPP score > 12 at one minute resulted in a statistically significant reduction in the number of patients who experienced pain (typical risk ratio (RR) 0.56, 95% CI 0.36 to 0.89; typical risk difference (RD) -0.23, 95% CI -0.39 to -0.86; number needed to treat to benefit (NNTB) 4). When pain was defined as an increase in PIPP > 4 there was a statistically significant reduction in the absolute number of patients who experienced pain at one minute (typical RR 0.70, 95% CI 0.52 to 0.94; typical RD -0.19, 95% CI -0.34 to -0.04; NNTB 5.3).

AUTHORS' CONCLUSIONS

The administration of topical proparacaine 30 seconds prior to the ophthalmological evaluation was associated with a reduction in pain scores especially at the time of speculum insertion. However, despite treatment, screening remains a painful procedure and the role of nonpharmacological and pharmacological intervention including different local anaesthetic agents should be ascertained in future randomised trials.

Masked trial of topical anesthesia for retinopathy of prematurity eye examinations

PURPOSE

To observe the effect of a topical anesthetic on pain and corneal clarity in premature infants undergoing eye examinations for retinopathy of prematurity (ROP).

METHODS

ROP examinations were performed on premature infants who were randomized to receive either proparacaine 0.5% or an artificial tear solution in the right eye. All infants received an artificial tear solution in the left eye. Assessment of discomfort was performed by use of the Premature Infant Pain Profile (PIPP) during examination of the right eye, with a painful event defined as a PIPP score≥11. The left eye was then examined and a comparison of corneal clarity was made between the 2 eyes.

RESULTS

A total of 39 examinations were performed on 34 infants: artificial tear solution was administered 17 times and topical proparacaine anesthetic 22 times. The mean PIPP score for those receiving artificial tears was 10.4 compared with 8.8 for the anesthetic group (p=0.17). Of the examinations without anesthetic, 65% were painful, compared with 27% with anesthetic (p=0.04). No effect on corneal clarity was observed in any examination.

CONCLUSIONS

The use of a topical anesthetic appears to marginally decrease pain and has no adverse effect on subjectively assessed corneal clarity during examination of premature infants for ROP.

Pain management during eye examinations for retinopathy of prematurity in preterm infants: a systematic review

AIM

To assess whether non-pharmacological and/or pharmacological measures lead to decreased pain during an eye examination in preterm infants.

METHODS

.

DESIGN

Systematic review.

SUBJECTS

Premature infants meeting the criteria for screening eye examination for retinopathy.

INTERVENTION

Databases were searched through the Ovid interface. Randomized and quasi-randomized controlled trials were included. Data were assessed independently by three reviewers.

MAIN OUTCOME MEASURES

Pain assessed by Premature Infant Pain Profile (PIPP) or physiological changes.

RESULTS

Eight studies were included and grouped according to intervention: oral sucrose (group 1), anaesthetic eye drops (group 2) and non-pharmacological measures (group 3). For group 1, the mean PIPP score with sucrose was 1.38 (WMD) (95% CI: 0.41-2.35) lower than that of placebo (p = 0.005). For group 2, one study showed a reduction of two points on the PIPP score with topical proparacaine, whereas another showed no benefit. For group 3, developmental care improved developmental scores and salivary cortisol in one study.

CONCLUSION

Sucrose reduced pain during the eye examination, whereas the efficacy of proparacaine was not consistent in the studies included. However, PIPP scores remained relatively high in all the studies; thus further research is required to delineate better pain reduction strategies.

Topical proparacaine and episcleral venous pressure in the rabbit

PURPOSE

To determine the effect of proparacaine-induced topical anesthesia on episcleral venous pressure (EVP).

METHODS

In anesthetized rabbits (n = 11), EVP was measured with a servonull micropressure system, with glass pipettes with 2- to 3-microm tips used to cannulate episcleral veins. Additional measurements included arterial, intraocular, and orbital venous pressures obtained by direct cannulation, to assess the ocular pressure gradients, and carotid blood flow and heart rate, to verify preparation stability. The protocol entailed 5 to 10 minutes of stable baseline recording followed by topical application of proparacaine (0.5%, 10 microL) with continued measurements for another 5 to 15 minutes.

RESULTS

Baseline EVP without topical anesthesia was 12.3 +/- 1.1 mm Hg. EVP decreased significantly to 8.7 +/- 0.9 mm Hg within minutes after application of proparacaine. A small decrease also occurred in intraocular pressure. All other measured variables were unchanged.

CONCLUSIONS

These results suggest that the episcleral circulation is under tonic neural control and that either an upstream resistance site is under tonic vasodilatory control or a downstream site is under vasoconstrictor control.

Liquid nitrogen cryotherapy of superior limbic keratoconjunctivitis

PURPOSE

To evaluate the effects of liquid nitrogen cryotherapy on superior limbic keratoconjunctivitis (SLK).

DESIGN

Interventional case series.

METHODS

In this clinical practice case series, the effects of liquid nitrogen cryotherapy on SLK were observed. Liquid nitrogen cryotherapy was performed using a Brymill E tip spray (0.013-inch aperture) with a double freeze-thaw technique. All subjects were outpatients who had local anesthesia with a single drop of topical proparacaine. The main outcome measure was the resolution of the disease process after treatment.

RESULTS

Four female patients (average age, 64 +/- 13 years) and seven eyes with SLK were treated with liquid nitrogen cryotherapy. Resolution of signs and symptoms occurred within two weeks. Disease recurred in two patients and three of seven eyes, although repeat cryotherapy eradicated SLK in all cases. The repeat cryotherapy was performed at three months postoperatively. There were no adverse ocular events.

CONCLUSIONS

Liquid nitrogen cryotherapy appears to be an effective alternative treatment for SLK as all subjects studied achieved long-term cures. Repeat cryotherapy may be necessary in some instances and may be performed three months after the first treatment.

Does prior instillation of a topical anaesthetic alter the pupillary mydriasis produced by tropicamide (0.5%)?

PURPOSE

It is common clinical practice to instill a topical anaesthetic prior to the instillation of a mydriatic agent into the eye. The main rationale for using the anaesthetic is to increase corneal permeability, so that more of the mydriatic agent reaches the receptor sites within the anterior chamber. It addition, as mydriatics generally cause stinging, prior use of an anaesthetic should reduce the degree of discomfort. The aim of the present study was to determine whether the efficacy of mydriasis produced by an antimuscarinic agent is enhanced by prior instillation of a topical anaesthetic.

METHOD

The study was performed using a double-masked protocol on 20 healthy young subjects. One drop of either proparacaine (proxymetacaine) (0.5%) or isotonic saline was instilled into the eye, followed by one drop of tropicamide (0.5%). Pupil diameter was measured using a customized photographic device at 0, 10, 20, 30 and 60 min following drug instillation. Additionally, subjects were asked to rate the degree of discomfort following the instillation of each drop on a scale from 0 (no discomfort) to 10 (agony).

RESULTS

There was no significant difference in either the rate of onset of mydriasis, or the maximum pupil diameter achieved between the two conditions. The mean change in pupil diameter produced by tropicamide after the instillation of saline or proparacaine was 2.31 and 2.28 mm, respectively. The mean discomfort scores following instillation of saline and proparacaine were 1.15 and 1.65, respectively, while mean discomfort scores following the instillation of tropicamide after saline or proparacaine were 4.00 and 0.85, respectively.

CONCLUSIONS

Instillation of a topical anaesthetic does significantly reduce the degree of discomfort produced by the instillation of tropicamide. However, it does not produce any significant increase in either the magnitude or rate of onset of mydriasis.

Selbstmedikation mit Lokalanästhetika durch Glaukompatienten bei der Teletonometrie

BACKGROUND

Self-tonometry, a supplementary measurement of the intraocular pressure in ophthalmology by glaucoma patients using an automatic tonometer, will become more and more important in the future. As long as the self-tonometry has to work in the contact modus with the ocular surface, home application of a topical anaesthetic by the glaucoma patient will be a requirement for a successful measurement. So far no severe problems within this controlled self-medication have been seen. Nevertheless, public health authorities believe patient health is put at high risk by the application of local anaesthetics during self-tonometry. As there are no clinical studies of the health care, we evaluated the local tolerability of a topical anaesthetic in line with self-tonometry employing a modified tonometer OCUTON S.

MATERIAL AND METHODS

A total of 100 glaucoma patients participated in a prospective clinical study of the routine clinical service in which each was monitored for 1 year. The telemonitoring involved self-tonometry for at least 6 months in every case and Ocuton S Proparakain-POS 0.5% eyedrops (proxymetacaine-HCl) were applied by the probands before every measurement of the intraocular pressure with a modified self-tonometer. Information regarding the local tolerability of the topical anaesthetic was analysed using a standardised questionnaire. The intensity of the following subjective symptoms was listed in separate visual analogue scales for: lacrimation, burning, foreign body sensation, mucus aggregation, pruritus and pain.

RESULTS

Information from 83 glaucoma patients on local tolerability of proparacaine eyedrops could be analysed. For several reasons no data could be gathered from 17 probands, which were refusal to complete the questionnaire, cancelled participation and, in two test persons, there emerged an allergic reaction (local eyelid redness and swelling) which necessitated a change to a different topical anaesthetic. In all other participants the application was carried out without any significant local or systemic symptoms or side-effects. Immediately after application of the eyedrops 36.1% of the test persons suffered a minor conjunctival hyperaemia which eased off within 1 h in 20.4% of these patients. Of the interviewed glaucoma patients 91.5% judged the single symptoms on the visual analogue scale between zero and medium intensity. The severest effects, according to the subjective evaluation, were felt in symptoms of burning with a score of 94 and lacrimation graded 96. The least intensity was established in the symptom of mucus aggregation where 72.3% rated this symptom in the visual analogue scale between 0 and 10. The other symptoms pruritus, feeling of pressure and foreign body sensation hardly differed in subjective ratings.

CONCLUSION

A self-medication with topical anaesthetics on undamaged ocular surfaces for self-tonometry purposes can be performed by glaucoma patients without a high risk potential. However, the application presupposes that routine ophthalmological examinations are carried out according to the ophthalmological associations' recommendations. Therefore, medical care concepts which integrate self-tonometry into routine ophthalmological services and comply with the complex requirements of a modern glaucoma management should be applied more often.

Posterior vitrectomy under topical anesthesia

BACKGROUND

To determine the safety and efficacy of topical anesthesia in posterior vitrectomy.

METHODS

A total of 93 patients (93 eyes) with various vitreoretinal diseases not needing scleral buckling and with short predicted duration of surgery underwent posterior vitrectomy under topical (49 eyes) or retrobulbar (44 eyes) anesthesia. Patients in the topical group were sedated with neuroleptic anesthesia. Postoperatively, patients were shown a visual analogue pain scale (VAPS) from 0 (no pain) to 10 (unbearable pain) to rate the levels of pain. The main outcome measures were overall and worst intraoperative pain scores, duration of surgery, and pain score during the administration of the retrobulbar anesthetic agent.

RESULTS

Mean surgical time was 57.9 minutes in the topical group and 56.6 minutes in the retrobulbar group (p > 0.05). The pain scores were not significantly different. Mean overall pain scores were 1.71 (SD 1.04, range 0-5) in the topical group and 1.38 (SD 1.04, range 0-3) in the retrobulbar group (p > 0.05). Mean worst pain scores were 3.20 (SD 1.30, range 1-7) and 2.95 (SD 0.73, range 1-4), respectively (p > 0.05). There was no significant correlation between duration of surgery and overall pain score in either group (r = 0.146, p = 0.356, and r = 0.174, p = 0.385, respectively). No patient required additional injection anesthesia in the topical group.

INTERPRETATION

Topical anesthesia combined with systemic sedation and analgesia in posterior vitrectomy procedures provided sufficient analgesic effects in selected patients needing no scleral buckling and with short predicted surgery time.

Topical anaesthesia alone versus topical anaesthesia with intracameral lidocaine for phacoemulsification

BACKGROUND

Cataract is defined as loss of transparency of the natural lens and is usually an age-related phenomenon. The only recognized treatment available for cataract involves surgery. An ideal anaesthetic should allow for pain-free surgery with no systemic or local complications. It should be cost effective and should facilitate a stress-free procedure for surgeon and patient alike. Topical anaesthesia involves applying anaesthetic eye drops to the surface of the eye prior to and during surgery. This has found large acceptance especially in the USA where it is used by 61% of cataract surgeons. Many surgeons who perform cataract surgery under topical anaesthesia also use intraoperative supplementary intracameral lidocaine (injected directly into the anterior chamber of the eye). The benefits and possible risks of intracameral lidocaine have been assessed by a number of randomized controlled trials, but the results have been conflicting and many of the endpoints have been heterogeneous.

OBJECTIVES

The primary objective of this systematic review was to assess pain during surgery and patient satisfaction with topical anaesthesia alone compared to topical anaesthesia with intracameral anaesthesia for phacoemulsification. The secondary objectives were to assess adverse effects and complications attributable to choice of anaesthesia and the need for additional anaesthesia during surgery.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 2), MEDLINE (1966 to May 2006), EMBASE (1980 to May 2006) and LILACs (1982 to 3 May 2006). We also searched the reference lists of the identified studies and the Science Citation Index. We did not have any language restriction.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) comparing topical anaesthesia alone to topical anaesthesia with intracameral lidocaine.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. For dichotomous outcomes data were presented as odds ratios. For continuous outcomes the weighted mean difference was employed. A random-effects model was used unless there were fewer than three trials in a comparison, where a fixed-effect model was used. We explored heterogeneity between trial results using a chi-squared test.

MAIN RESULTS

A total of eight trials comprising of 1281 patients were identified for analysis. Our data comparison showed a significantly lower intraoperative pain perception in patient groups using supplementary intracameral lidocaine, although the difference was small. No significant difference was demonstrated between the groups receiving topical anaesthesia alone and topical combined with intracameral anaesthesia in terms of the need for supplemental anaesthesia, intraoperative adverse events or corneal toxicity.

AUTHORS' CONCLUSIONS

The use of intracameral unpreserved 1% lidocaine is an effective and safe adjunct to topical anaesthesia for phacoemulsification cataract surgery.

Phacoemulsification in vitrectomized eyes under topical anesthesia

PURPOSE

To study phacoemulsification in vitrectomized eyes under topical anesthesia, assessing anesthetic and intraoperative characteristics and complications.

METHODS

A prospective study was performed on 52 eyes of 51 patients who underwent phacoemulsification of cataract with intraocular lens implantation under topical anesthesia, having previously undergone pars plana vitrectomy. Surgical and anesthetic observations and complications were recorded, as were visual outcomes.

RESULTS

Ninety-two percent of patients had improved visual acuity postoperatively with only one patient having visual loss as a result of surgery. The most common intraoperative observations were of a deep anterior chamber, posterior capsular plaques, posterior synechiae, and nuclear sclerotic cataracts. Topical anesthesia proved satisfactory in 96%, with only two patients requiring intracameral lignocaine 1%; no patients required conversion to injection anesthesia. There were no major operative or postoperative complications.

CONCLUSIONS

Phacoemulsification in vitrectomized eyes can be challenging, but is visually rewarding. Topical anesthesia proved satisfactory for the vast majority of cases, with none of our patients requiring conversion to injection anesthesia.

Subtenon lidocaine vs topical proparacaine in adult strabismus surgery

Intraoperative subtenon 2% lidocaine and topical 0.5% proparacaine in patients undergoing strabismus surgery were compared. No additional systemic analgesics and sedatives were used. Mean and total pain scores intraoperatively and postoperatively were not different. Each anesthetic agent provides good intraoperative anesthesia and postoperative analgesia. Topical 0.5% proparacaine may be preferred because of its easy administration and fewer side effects, lack of hospital admission, and immediate and predictable alignment of the eyes.

Assisted local anaesthesia for endoscopic dacryocystorhinostomy

BACKGROUND

Endoscopic dacryocystorhinostomy is traditionally performed under general anaesthesia. However, there are reports in the literature of various local anaesthetic techniques with or without sedation for this procedure. An effective and acceptable local anaesthetic technique enables the avoidance of the risks associated with general anaesthesia, particularly for elderly patients, with the added benefit of reduced bleeding, reduced nausea and vomiting, and reduced length of hospital stay and thus health care cost savings. This study aims to evaluate the safety and patient acceptance of a minimally invasive assisted local anaesthetic technique for endoscopic dacryocystorhinostomy.

METHODS

A prospective questionnaire-based study is presented of 24 consecutive adult patients who underwent 26 endoscopic dacryocystorhinostomies in a day surgery including 22 primary and four revision procedures performed by one surgeon under local anaesthesia and sedation over a 4-month period.

RESULTS

Apart from persistent postoperative vomiting in one patient there were no anaesthetic complications. There were no instances of epistaxis. The mean pain score on a visual analogue scale of 0-10 was 1.56 and 56% reported no pain. Ninety-two per cent would recommend the procedure to others.

CONCLUSION

This assisted local anaesthetic technique for endoscopic dacryocystorhinostomy is safe and acceptable to patients.

Assessment of bacterial contamination of three multidose ophthalmic solutions

OBJECTIVE

To investigate the frequency of bacterial contamination of multidose proparacaine hydrochloride, tropicamide, and eyewash bottles used in veterinary ophthalmology examination rooms during normal operating procedures.

METHODS

Three representative bottles each of proparacaine hydrochloride, tropicamide, and purified water eye wash were opened at the same time, numbered, and placed into small animal examination rooms. Doctors, students and technicians who were using the solutions were blinded to the study. Aerobic cultures were obtained at the time of opening (time 0), at 1 week (time 1), and at 2 weeks after opening (time 2) the bottles. The sites cultured included a drop of each solution, the inside of the bottle cap, the tip of the bottle, and the bottle threads and medication residue found in these threads.

RESULTS

Aerobic cultures of tropicamide and proparacaine had no growth of bacteria from any of the evaluated sites. Staphylococcus epidermidis was cultured from the tip of one bottle of eye wash after 1 week.

CONCLUSIONS

We conclude that proparacaine, tropicamide, and eyewash solutions used in veterinary examination rooms are adequately preserved for use in ophthalmic examination. They have a low level of bacterial contamination 1 or 2 weeks after opening when used and stored according to the recommendations of the product manufacturers and previous studies.

Effect of proparacaine on central corneal thickness values: an evaluation using noncontact specular microscopy and pentacam

PURPOSE

To study the effect of 1 drop of 0.5% proparacaine on central corneal thickness values monitored by nonspecular microscopy and Pentacam, a corneal topographer with rotating Scheimpflug camera.

METHODS

Forty subjects were divided into 2 groups with 1 group measured with a noncontact specular microscope and the other group with Pentacam (Oculus, Inc., Wetzlar, Germany). One eye was randomly selected, and corneal thickness values were monitored every 30 seconds for 10 minutes. Baseline corneal thickness values were defined as the average of all measurements taken over 10 minutes. One drop of 0.5% proparacaine was instilled, and the corneal thickness values were monitored by the same instrument every 30 seconds for another 10 minutes after drug instillation.

RESULTS

The 2 groups shared similar age range, refractive error, and baseline corneal thickness values. The spontaneous variation of corneal thickness values was within 3 mum for 10 minutes before drug instillation. There was no obvious trend of corneal thickness value change after the instillation of local anesthetics. The variation of corneal thickness values against the baseline was within 5 mum.

CONCLUSION

One drop of 0.5% proparacaine does not produce any significant change in central corneal thickness.

Duration of corneal anesthesia following topical administration of 0.5% proparacaine hydrochloride solution in clinically normal cats

OBJECTIVE

To determine duration of corneal anesthesia following topical administration of 0.5% proparacaine hydrochloride solution in domestic shorthair (DSH) cats.

ANIMALS

20 clinically normal DSH cats.

PROCEDURES

Baseline corneal touch threshold (CCT) was established by use of a Cochet-Bonnet aesthesiometer. Treatment consisted of a single 50-microL topical application of an ophthalmic preparation of 0.5% proparacaine solution to a randomly selected eye of each cat. The corneal touch threshold was assessed 1 and 5 minutes after application to the cornea and at 5- minute intervals thereafter for 60 minutes.

RESULTS

Corneal sensitivity, as determined by Cochet-Bonnet aesthesiometry, was significantly reduced from baseline for 25 minutes following topical administration of ophthalmic proparacaine. Maximal anesthetic effect lasted 5 minutes.

CONCLUSIONS AND CLINICAL RELEVANCE

As determined by Cochet-Bonnet aesthesiometry, duration of anesthetic effects on the cornea induced by a single topical application of an ophthalmic preparation of 0.5% proparacaine solution in DSH cats is considerably shorter than the reported duration of corneal anesthesia in dogs.

Topical Anesthesia in Transconjunctival Sutureless 25-Gauge Vitrectomy for Macular-Based Disorders

PURPOSE

To evaluate the safety and feasibility of topical anesthesia in vitrectomy using the transconjunctival sutureless 25-gauge system (TSV 25G).

METHODS

TSV 25G vitrectomy was performed prospectively in 46 eyes of 46 patients with macular-based disorders, including macular holes (n = 31), idiopathic epiretinal membranes (n = 11), and vitreoretinal traction syndrome (n = 4). Topical anesthesia was administered in each patient by instilling 2% Alcaine at 5 min intervals, three times before surgery. Additional Alcaine drops were given as a supplementation if needed during the operation. The levels of intraoperative analgesia were graded from 1 (adequate) to 3 (inadequate).

RESULTS

Thirty-one patients (67.4%) tolerated the procedure well, with no additional anesthetic agent. Thirteen patients (28.3%) required additional topical anesthesia and 2 patients (4.3%) required a systemic sedative. Intraoperative pain occurred when the sclera was pierced by the microcannula and when sclera indentation was performed. No patient required additional retrobulbar or peribulbar anesthesia. There was no intraoperative complication which was specifically related to topical anesthesia.

CONCLUSION

Topical anesthesia permits the successful management of some surgically less complex vitreoretinal disorders when the TSV 25G is used.

Pupil dilation using a pledget sponge: a randomized controlled trial

BACKGROUND

To show that a pledget soaked in mydriatics and placed in the lower conjunctival fornix is as effective as drops in providing mydriasis for cataract surgery.

METHODS

A randomized, masked, controlled trial of 56 patients assigned to either a pledget group (n=25) or a control eye drops group (n=31) was carried out. Controls had the routine practice of repeated topical mydriatic drops: tropicamide, phenylepherine and atropine. The trial group had a 3-mm pledget trimmed, soaked in mydriatics and placed in the inferior fornix for 20 min. Pupil diameter was measured using a photographic technique with a standard scale shown in each picture. Two masked observers measured the pupils using the scale of the ruler in the developed photograph. All patients completed a 0-10 stinging score prior to surgery.

RESULTS

There were no complications. The mean pupil diameter in the control group was 7.23 (6.91-7.94 95% confidence intervals [CI]) and 7.44 (6.96-7.92 95% CI) in the pledget group. There was no statistically significant difference in pupil diameter between the two groups: difference between means 0.21 (-0.32 to 0.75 95% CI) and Student's t-test of the difference between means (t=0.8 and two-tailed) probability P=0.43. There was no significant difference in the stinging scores: Mann-Whitney test P=0.69.

CONCLUSION

The use of a pledget cellulose sponge to deliver mydriatics prior to cataract surgery is as effective as the conventional method of repeated drop administration and was not associated with any adverse effects.

Prospective Randomized Double-Masked Trial to Evaluate Perioperative Pain Profile in Different Stages of Simultaneous Bilateral LASIK

PURPOSE

To evaluate the perioperative pain profile in simultaneous bilateral LASIK.

METHODS

Fifty consecutive Chinese patients undergoing simultaneous bilateral LASIK were randomly allocated to have either the right or left eye operated first. The pain scores for each eye at speculum placement, microkeratome cut, laser ablation, and at 15, 30, and 45 minutes after the procedure were recorded. In addition, an overall score for the whole operation was evaluated immediately after the procedure for each eye. Comparisons between eyes and among different stages of the procedures were analyzed.

RESULTS

The second eye was significantly more painful than the first eye at the stage of speculum placement and microkeratome pass (P < 0.001). Laser ablation was the least painful stage for both eyes. There were no statistical differences in pain scores for the postoperative period.

CONCLUSION

Higher pain scores were associated with the stages involving eyelid manipulation. In patients with small palpebral fissures where stretching of the eyelid structures are anticipated, supplementary anesthesia for the lid region should be considered when required.

Comparison of Corneal Thickness After the Instillation of Topical Anesthetics

PURPOSE

To compare changes in human corneal thickness after the instillation of proparacaine with those after oxybuprocaine instillation with time over a period of 10 minutes.

METHODS

Eighteen healthy young participants were recruited. Proparacaine was used in the right eye and oxybuprocaine in the left. Right and left baseline corneal thicknesses were measured every 30 seconds for 10 minutes using a noncontact specular microscope by 1 observer. Baseline corneal thickness was defined as the average of all values taken over 10 minutes. Changes in corneal thickness were measured every 20 seconds for 10 minutes after the administration of 1 drop of 0.5% proparacaine onto the right cornea and 1 drop of 0.4% oxybuprocaine onto the left cornea.

RESULTS

Mean baseline right cornea thickness was 531 +/- 45 microm, and that of the left cornea was 531 +/- 42 microm. The corneal thickness after proparacaine increased by 8.6 microm ( approximately 4.5-12.6 microm, 95% CI) and then returned to baseline within 80 seconds. Corneal thickness after applying oxybuprocaine increased by 7.7 microm (3.6-11.2 microm, 95% CI) and then returned to baseline within 80 seconds. There was a second transient increase about 5 minutes later after proparacaine instillation but no additional transient increase after oxybuprocaine instillation.

CONCLUSION

Oxybuprocaine is similar to proparacaine in terms of the severity of its effect on corneal thickness. Corneal thickness instability may occur for 5 minutes after proparacaine administration. Changes in corneal thickness after topical anesthetic instillation should be considered when performing measurements for refractive surgery or central corneal thickness in glaucoma patients.

Patient pain during stretching of small pupils in phacoemulsification performed using topical anesthesia

PURPOSE

To assess the pain experienced by patients with small pupils during pupil stretching in phacoemulsification performed using topical anesthesia.

SETTING

Royal Victoria Eye & Ear Hospital and Mater Misericordiae University Hospital, Dublin, Ireland.

METHODS

This was a prospective study that included 26 eyes with small pupils requiring mechanical pupil stretching during phacoemulsification cataract surgery performed under topical anesthesia without sedation.

RESULTS

The mean pain score for the instillation of anesthetic drops (2.02) was higher than the mean pain score for the pupil stretch (1.63), but this difference was not significant (signed rank test = -32; P = .2738). There was no significant correlation between the duration of surgery and the overall pain score (r = 0.345; P = .08). There was no significant correlation between change in pupil size and either the pupil stretch score (r = -0.069; P = .74) or the overall pain score (r = -0.032; P = .8739).

CONCLUSIONS

Pupil stretching during phacoemulsification in patients with small pupils was performed with minimal patient-reported pain using topical anesthesia. Stretching small pupils with a mechanical device during phacoemulsification performed under topical anesthesia was a safe procedure and did not result in significant patient discomfort.

Flap suturing with proparacaine for recurrent epithelial ingrowth following laser in situ keratomileusis surgery

PURPOSE

To evaluate the safety and efficacy of flap suturing with proparacaine application for the management of recurrent epithelial ingrowth following laser in situ keratomileusis (LASIK).

SETTING

Private consultation practice and Department of Ophthalmology, Rush University, Chicago, Illinois, USA.

METHODS

Six eyes of 5 patients with recurrent epithelial ingrowth had flap lifting followed by debridement of interface epithelial cells, interface application of proparacaine, and the placement of interrupted 10-0 nylon sutures.

RESULTS

Four eyes achieved a best corrected visual acuity (BCVA) of 20/40 or better. Two eyes required repeat debridement with suturing and were stable with at least a 1-year follow-up. No eye lost more than 1 line of BCVA. Three eyes regained excellent uncorrected visual acuity due to a reduction in induced astigmatism.

CONCLUSIONS

Recurrent epithelial ingrowth following LASIK surgery can be a visually debilitating condition. Flap suturing with interface proparacaine application may be effective in preventing further recurrences of epithelial ingrowth after initial debridement.

Efficacy of sucrose to reduce pain in premature infants during eye examinations for retinopathy of prematurity

BACKGROUND

Eye examinations for retinopathy of prematurity (ROP) are painful to the neonate. The use of topical anesthetic for eye examinations to evaluate ROP is routine in our neonatal intensive care unit (NICU), but does not completely suppress painful responses. Sweet solutions have been shown to reduce procedural pain in newborns.

OBJECTIVE

To examine whether the addition of sucrose 24% to topical anesthetic improves procedural pain control during the ROP eye examination.

METHODS

Neonates born at < or = 30 weeks' gestation were included in this placebo-controlled, double-blind, crossover study. Patients were randomly assigned to receive treatment with either proparacaine HCl ophthalmic solution 0.5% plus 2 mL of sucrose 24% or proparacaine HCl ophthalmic solution 0.5% plus 2 mL of sterile water (placebo) prior to an eye examination. In a subsequent eye examination, each patient received the alternate treatment. Oral sucrose and sterile water were prepared in the pharmacy in identical syringes, and physicians, nurses, and pharmacists in the NICU were blinded to the treatment given. Pain was measured using the Premature Infant Pain Profile (PIPP) scoring system, which measures both physical and physiologic measures of pain, and the scores were simultaneously assessed by 2 study nurses. PIPP scores were recorded 1 and 5 minutes before and after the eye examination and during initial placement of the eye speculum. The same ophthalmologist performed all eye examinations. Several different definitions of a pain response were investigated.

RESULTS

Twenty-three infants were studied, with 12 receiving sucrose and 11 receiving placebo as the first treatment. For 3 of the 5 definitions of pain response, patients experienced significantly less pain at speculum insertion with sucrose than with placebo. After the ROP examination, pain responses were similar with either sucrose or placebo.

CONCLUSIONS

Oral sucrose may reduce the immediate pain response in premature infants undergoing eye examination for ROP.

Duration of effect and effect of multiple doses of topical ophthalmic 0.5% proparacaine hydrochloride in clinically normal dogs

OBJECTIVE

To determine the duration of effect and the effect of multiple doses of topical ophthalmic application of 0.5% proparacaine hydrochloride on corneal sensitivity in clinically normal dogs.

ANIMALS

8 clinically normal dogs.

PROCEDURE

Dogs were randomly allocated to treatment order in a 2 x 2 (period X treatment) crossover study. Treatments consisted of topical application of ophthalmic 0.5% proparacaine (1 drop or 2 drops at a 1-minute interval); treatments were applied to both eyes. A Cochet-Bonnet aesthesiometer was used to determine corneal touch threshold (CTT) before corneal application, 1 and 5 minutes after corneal application, and at 5-minute intervals thereafter for 90 minutes.

RESULTS

The CTT value before treatment differed significantly from CTT values after treatment until 45 minutes after application in the 1-drop group and until 55 minutes after application in the 2-drop group. As determined by use of the Cochet-Bonnet aesthesiometer, a significantly greater anesthetic effect was detected for the 2-drop treatment, compared with the effect for the 1-drop treatment, at 30, 35, 40, 45, 50, and 55 minutes after application. Maximal anesthetic effect lasted for 15 minutes for the 1-drop treatment and 25 minutes for the 2-drop treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Duration of corneal anesthetic effect induced by topical ophthalmic application of 0.5% proparacaine in dogs of this study is considerably longer than that reported elsewhere. Serial application of doses of 0.5% proparacaine increases the duration and magnitude of corneal anesthetic effects.

[A subjective evaluation of epibulbar and etrobulbar anesthesia in cataract phacoemulsification]

Described in the paper are comparative descriptions of the efficiency of epibulbar and retrobulbar anesthesia made through evaluating the sensation of pain experienced by patients in cataract phacoemulsification and IOL implantation. The patients (1046 subjects, aged 28 to 89) were shared between 2 groups; they received an identical premedication by midazolam, peroral administration, 3.75 mg in 1 h before surgery. Epibulbar anesthesia with 1% proximetacaine hydrochloride, administered via instillator, was used in Group 1 (524 patients). Analgesia with 2% lidocaine hydrochloride solution (injections, 1:1) was made in Group 2 (522 patients). The subjective pain sensations experienced by patients during subsequent surgical stages were evaluated by an international 6-point scale. The pain sensations were found to vary from 0 to 4 points (mean point value--2.25) in Group 1. The most severe pain was experienced by the patients during the introduction of the phacoemulsificator tip into the anterior chamber of the eye (mean pain value--1.75 points) as well as during IOL implantation (mean pain value--1.25). The instillator-based analgesia does not normally provoke any complications and is well tolerated by patients; it can be recommended for cataract phacoemulsification.

Effect of midazolam on anxiety level and pain perception in cataract surgery with topical anesthesia

PURPOSE

To study the effect of sedation on patients' anxiety level and perception of pain during cataract surgery under topical anesthesia.

SETTING

Royal Eye Infirmary, Plymouth, England.

METHODS

This prospective controlled double-blind clinical trial comprised 100 consecutive patients having routine phacoemulsification with posterior chamber intraocular lens implantation under topical anesthesia by a single experienced surgeon. Patients were randomized to receive intravenous midazolam (0.015 mg/kg body weight) 15 minutes before surgery or no sedation. The main evaluation criteria were the anxiety based on the 6-item, short form of the State-Trait Anxiety Inventory, the pain score using a visual analog scale, and overall patient satisfaction.

RESULTS

All operations were uneventful, and no side effects were noted from the use of midazolam. Anxiety scores were significantly higher on arrival at the hospital than just before the commencement and after the conclusion of the surgery in both groups (P<.05). Patients were less anxious after administration of midazolam, but this did not achieve statistical significance. The mean pain score was 0.29 (range 0 to 4) in the sedation group and 0.38 (range 0 to 4) in the control group; the difference between groups was not statistically significant. The patients were equally satisfied in both groups, with mean scores of 3.84 (range 0 to 4) and 3.88 (range 2 to 4), respectively.

CONCLUSIONS

Patients who had cataract surgery under topical anesthesia were highly satisfied with their operative experience and reported minimal pain during surgery. Anxiety levels diminished after arrival at the hospital, possibly because of reassurance by experienced staff. Intravenous midazolam did not seem to significantly reduce pain or anxiety.

In vivo transscleral iontophoresis of amikacin to rabbit eyes

The objectives of these studies were to determine the amount and distribution of the aminoglycoside antibiotic amikacin delivered to rabbit eyes following transscleral iontophoresis and to determine the inter-study reproducibility of delivery over three identical studies. New Zealand White rabbits (N = 6 per dose group) were treated with a 200-mg/mL amikacin solution at 0, 2, 3 or 4 mA of (+) DC current for 20 minutes. Amikacin concentrations in eye tissues were highest with the 4-mA treatment. Concentrations for all three studies at this current were approximately 5.4, 40, 41, 343, and 92 mcg/g in the vitreous humor, anterior segment, non-treated hemisphere of the sclera, treated hemisphere of the sclera, and retina/choroid, respectively. These values were approximately 27, 50, 40, 10, and 13 fold greater than in the 0-mA control group and are well above the in vitro minimum inhibitory concentrations (MICs) for this drug. Inter-study reproducibility (measured as %CV) depended on the tissue type and treatment group and ranged from 8% for the retina/choroid to 51% for the anterior segment in the 4-mA group. Pretreatment with topical proparacaine hydrochloride local anesthetic did not affect amikacin delivery and total drug delivered was not affected by delivery time for the same total charge administered. Therapeutically relevant amounts of amikacin were delivered into eye tissues in a reproducible and controllable manner.

Local anaesthesia for vitreoretinal surgery: an audit of patient and surgical experience

PURPOSE

Local anaesthesia for vitreoretinal surgery is little used as these procedures are deemed to be too long and uncomfortable for patients to tolerate. In this unit anterior intraconal local anaesthesia is used for most routine surgery. We undertook an audit to ensure that surgical standards and patient acceptability were not compromised.

METHODS

A prospective observational audit was performed. Audit data included: Grade of anaesthetist and surgeon; details of anaesthetic and operation; compliance of patient; operating conditions and pain scores. Anaesthesia was provided with a combined peribulbar and intraconal anaesthetic, using bicarbonate buffered lignocaine and bupivacaine 50:50 mixture.

RESULTS

135 (76%) had local anaesthesia alone, 13 (7%) had local anaesthesia with sedation and 29 (16%) had general anaesthesia. 96.4% of patients were compliant and 98.8% of operating conditions were good or excellent. The mean perioperative pain score was 0.1 (range of 0-1), 97% said they would choose local anaesthesia again.

CONCLUSIONS

LA for vitreoretinal surgery is a useful and flexible method of anaesthesia, which has been shown to have excellent patient tolerance.

The antibacterial effect of topical anesthetic proparacaine on conjunctival flora

PURPOSE

To investigate the antibacterial effect of topical anesthetic proparacaine on conjunctival flora.

METHODS

One hundred and forty-four eyes of 72 patients awaiting cataract surgery were included in the study. A commercially available solution of proparacaine, preserved with benzalkonium chloride 0.01%, was instilled in one eye of all subjects while the vehicle solution, including the same concentration of preservative in aqueous solution, was administered to the other eye. Conjunctival cultures were taken from all eyes before and 15 minutes after the instillation of proparacaine and the vehicle.

RESULTS

Of the 144 eyes, 76 (52.8%) had positive-conjunctival cultures with the most commonly isolated organisms being coagulase-negative staphylococci in each group. Of the 76 culture-positive eyes, 40 (52.6%) received proparacaine and 36 (47.4%) the vehicle preparation. Fifteen minutes after the instillation of proparacaine and the vehicle eyedrops, four eyes (10%) and 12 eyes (33.3%) had culture-positive conjunctival smears, respectively. Proparacaine significantly reduced the number of culture-positive eyes (p = 0.0003), in contrast to the vehicle (p = 0.21).

CONCLUSION

A topical anesthetic, proparacaine, demonstrates antibacterial effects on the conjunctival flora.

Evaluation of an anesthetic regimen for retroorbital blood collection from mice

Many Institutional Animal Care and Use Committees require anesthetization of mice for retroorbital blood collection procedures. Optimal anesthetic regimens should provide chemical restraint and adequate analgesia for a sufficient but otherwise minimal duration. This study was conducted to evaluate the effectiveness, safety, and practical utility of the general anesthetic combination of ketamine and medetomidine with and without the topical anesthetic proparacaine. In addition, we sought to evaluate the reversal of general anesthesia with atipamezole. The findings suggest that the combination of ketamine, medetomidine, proparacaine, and atipamezole is a safe and humane anesthetic regimen for retroorbital collection of blood samples from mice.

A randomized comparison study of drop versus spray topical cycloplegic application

PURPOSE

To evaluate the acceptance of ocular spray administration.

METHODS

A randomized, single-masked comparison in a cohort of children from 3 to 13 years. Assessment of patient pain was recorded on a visual analog scale. Cycloplegia was assessed by an ophthalmologist masked to the assignment. A questionnaire was used to assess patient acceptance. 126 patients participated. The average age was 7.7 years for spray, 7.1 for drops.

RESULTS

Pain (higher number = more painful): means: 41/100 for spray; 35/100 for drops (P=0.28). No difference in cycloplegia noted (i.e., satisfactory in all subjects). Subjective acceptance: high in both patient groups, but a preference for spray was noted (P=0.06). No untoward drug reactions occurred with either method.

CONCLUSIONS

Cycloplegic spray was as acceptable, or more acceptable than drops. Cycloplegia was comparable for the two methods. Spray application of cycloplegic drugs is a satisfactory route of topical administration for children.

In vivo confocal Raman spectroscopy of the human cornea

PURPOSE

To investigate the feasibility of a confocal Raman spectroscopic technique for the noninvasive assessment of corneal hydration in vivo in two legally blind subjects.

METHODS

A laser beam (632.8 nm; 15 mJ) was maintained on the cornea by using a microscope objective lens (x25 magnification, NA = 0.5, f = 10 mm) both for focusing the incident light as well as collecting the Raman backscattered light, in a 180 degrees backscatter configuration. An optical fiber, acting as the confocal pinhole for elimination of light from out-of-focus places, was coupled to a spectrometer that dispersed the collected light onto a sensitive array detector for rapid spectral data acquisition over a range from 2,890 to 3,590/cm(-1). Raman spectra were recorded from the anterior 100-150 microm of the cornea over a period before and after topical application of a mild dehydrating solution. The ratio between the amplitudes of the signals at 3,400/cm(-1) (OH-vibrational mode of water) and 2,940/cm(-1) (CH-vibrational mode of proteins) was used as a measure for corneal hydration.

RESULTS

High signal-to-noise ratio (SNR = 25) Raman spectra were obtained from the human corneas by using 15 mJ of laser light energy. Qualitative changes in the hydration of the anteriormost part of the corneas could be observed as a result of the dehydrating agent.

CONCLUSION

With adequate improvements in system safety, confocal Raman spectroscopy could potentially be applied clinically as a noninvasive tool for the assessment of corneal hydration in vivo.

Cycloplegia in African-American children

PURPOSE

The selection of a cycloplegic agent depends on the desired outcome, the characteristics of the patient receiving the drug, and the associated risks. The Orinda Longitudinal Study of Myopia (OLSM) has used 1% tropicamide to assess the ocular components and cycloplegic refractions in a large cohort of predominantly Caucasian children. Although tropicamide has provided adequate cycloplegia and mydriasis for the OLSM cohort, conventional clinical wisdom and scientific investigations have suggested that tropicamide might not produce adequate cycloplegia and mydriasis for subjects with darker iris pigmentation. In this study one drop of 1% tropicamide followed by one drop of 1% cyclopentolate was used to determine their effectiveness in producing adequate cycloplegia and mydriasis for cycloplegic refraction and ocular component measurements in a group of African-American children.

METHODS

Nineteen children [age range 5.5 to 15.6 years, mean 8.4 years +/- (SD) 2.5 years] were tested at Family HealthCare of Alabama, Eutaw, AL. Their accommodative responses were measured using a Canon R-1 autorefractor prior to and at 30, 45, and 60 min after instillation of one drop of 0.5% proparacaine, 1% tropicamide (Mydriacyl), and 1% cyclopentolate (Cyclogyl) in both eyes. A target of 20/155 letters in a 4x4 grid positioned behind a +6.50 diopter (D) Badal lens provided accommodative stimuli of 1.00 D, 2.00 D, and 4.00 D.

RESULTS

All results are presented as mean +/-1 SD. Pupils, measured from video frames, dilated rapidly and maximally at 30 min after instillation of eye drops (7.3+/-0.5 mm) Predilation, the mean accommodative responses were 0.17+/-0.29 D for the 1.00 D stimulus, 1.01+/-0.40 D for the 2.00 D stimulus, and 2.77+/-0.74 for the 4.00 D stimulus. At 30 min after drop instillation, the responses were 0.07+/-0.14 D for the 1.00 D stimulus, 0.36+/-0.35 D for the 2.00 D stimulus, and 0.77+/-0.61 for the 4.00 D stimulus. Results were very similar at 45 and 60 min after drop instillation.

CONCLUSIONS

Combining 1% tropicamide and 1% cyclopentolate was very effective in providing both cycloplegia and mydriasis adequate for ocular biometry and cycloplegic refractions 30 min after drop instillation in African-American children.

Randomised prospective masked study comparing patient comfort following the instillation of topical proxymetacaine and amethocaine

AIMS

To evaluate the claim that topical proxymetacaine produces little or no discomfort on instillation by comparing it against topical amethocaine.

METHODS

This randomised, masked, double blind, prospective study involved 53 consecutive patients. Each patient received one drop of amethocaine 0.5% in one eye and one drop of proxymetacaine 0.5% in the other. The duration of the stinging sensation and degree of discomfort (using descriptive and a linear analogue method) for each topical anaesthetic was assessed.

RESULTS

The mean duration of stinging was 3.2 seconds for proxymetacaine and 22.1 seconds for amethocaine the difference being statistical significant (p < 0.001). The mean descriptive discomfort score was 2.6 for proxymetacaine and 14.2 for amethocaine (p = 0.01). The mean linear analogue score was 5.8 for proxymetacaine and 35.6 for amethocaine (p < 0.001). Proxymetacaine had a successful tonometry rate of 93% and amethocaine 98%.

CONCLUSION

This clinical study confirms that proxymetacaine is more comfortable on instillation than amethocaine. Minimising unnecessary patient discomfort is not only ideal, but encourages cooperation in apprehensive patients especially in children.

Topical anesthesia: Proxymetacaine versus Amethocaine for clear corneal phacoemulsification

PURPOSE

To evaluate the use of proparacaine (Proxymetacaine) versus tetracaine (Amethocaine) as the topical anesthetic agent for phacoemulsification cataract surgery using a 3.5 mm clear corneal sutureless incision.

SETTING

Harold Wood Hospital, Romford, Essex, United Kingdom.

METHODS

This prospective study comprised 40 randomly selected patients. Twenty were given Proxymetacaine and 20, Amethocaine. The level of discomfort experienced during delivery of the topical anesthetic agent and during and immediately after surgery was measured using a pain score. During surgery, topical anesthesia was supplemented by intracameral lignocaine 1%.

RESULTS

Patients given Proxymetacaine experienced no stinging sensation during its administration; those given Amethocaine reported varying degrees of discomfort. The difference between groups was statistically significant (P < .01). There was no difference between groups in the amount of discomfort experienced intraoperatively or postoperatively.

CONCLUSION

Proxymetacaine is the topical analgesic of choice for phacoemulsification because it produced no discomfort on administration yet had the same analgesic properties as Amethocaine.

Experimental study of tetrodotoxin, a long-acting topical anesthetic

PURPOSE

To determine the effectiveness and toxicity of tetrodotoxin for use as a long-acting topical anesthetic.

METHODS

Four groups of six rabbits each received a 40-microl aliquot of either tetrodotoxin in one of three concentrations (10 mM, 1 mM, or 0.1 mM) or proparacaine 0.5% into the inferior conjunctival cul-de-sac of one eye, with the fellow eye of each rabbit receiving 40 microl of a 60-mM, pH 4.3 sodium citrate vehicle as a control. Corneal sensation was tested for up to 8 hours after administration of drugs, and response was noted by no blink, partial blink without full eyelid closure, and full blink. Slit-lamp examination at 12 and 24 hours after administration and pachymetry before and 24 hours after administration were performed to detect corneal toxicity.

RESULTS

Rabbits receiving all three concentrations of tetrodotoxin did not demonstrate any ocular irritation, corneal thickening, or signs of systemic toxicity. At a dose of 10 mM, tetrodotoxin produced an anesthetic effect lasting up to 8 hours. At 1 mM, tetrodotoxin was an effective but shorter-acting anesthetic. At 0.1 mM, tetrodotoxin had no significant anesthetic effect. Proparacaine-treated rabbits initially were anesthetic, but this effect was largely gone by 1 hour and completely gone by 3 hours.

CONCLUSIONS

Tetrodotoxin is a long-acting topical anesthetic in the rabbit cornea. Although additional toxicity studies are required, tetrodotoxin may provide an effective, long-lasting topical anesthetic for use in pain control after corneal procedures such as photorefractive keratectomy.

Dilute topical proparacaine for pain relief after photorefractive keratectomy

PURPOSE

The purpose of the study is to determine whether there is a nonanesthetic and nontoxic concentration of topical proparacaine that can be applied repeatedly to the cornea to reduce pain after photorefractive keratectomy (PRK).

METHODS

Part I: To determine a nonanesthetic concentration, the corneal sensitivity of 50 healthy volunteers was assessed using aesthesiometry before and after a drop of either 0.01%, 0.025%, 0.05%, 0.1%, or 0.2% topical proparacaine. Ten volunteers similarly were tested with multiple doses of 0.05% proparacaine. To evaluate toxicity, ten healthy volunteers self-administered 0.05% proparacaine to one eye and placebo to the other eye every 15 minutes for 12 hours on day 1 and every hour for 12 hours on days 2 through 7. Subjects were assessed throughout the week using visual acuity, slitlamp examination, aesthesiometry, and ultrasonic pachometry. Part II: In a prospective, double-masked study, 34 patients who underwent PRK (48 eyes) self-administered either topical 0.05% proparacaine or placebo for 1 week after PRK as needed to reduce pain. Patients recorded their pain score before and after drop use and answered a pain-relief questionnaire.

RESULTS

Part I: Proparacaine concentrations greater than or equal to 0.1% eliminated sensation from some corneas; concentrations of less than or equal to 0.05% were never fully anesthetic. No corneal toxicity was observed except for some minimal punctate staining in both treatment and placebo eyes. Part II: Patients in the treatment group had significantly more pain relief (P < 0.001) for a longer period (P < 0.001) than did patients in the control group. Average change in pain score was significantly greater in the treatment group (P < 0.002). No significant difference in the number of days needed to reach complete epithelial healing was found between the two groups (P < 0.18).

CONCLUSIONS

Dilute (0.05%) topical proparacaine is nonanesthetic and nontoxic, and can be used safely for at least 1 week to reduce pain after PRK.

Drop, then decide approach to topical anesthesia

I developed an approach to topical anesthesia--drop, then decide--with the goal of increasing the percentage of patients able to have topical anesthesia for anterior segment surgery. This study comprised 150 consecutive surgeries performed using the technique, including cataract extraction with intraocular lens (IOL) implantation, trabeculectomy, combined procedures, and McCannel suturing. Six patients also had anterior vitrectomy. Patients were not preselected. All cases were initiated with topical anesthesia and supplemented with at least mild intravenous sedation by an anesthesiologist. The decision on whether to use anesthetic blocks was made after evaluating patient response early in the surgery. The approach had an overall success rate (no regional block needed) of 89.3%; 92.0% of the cataract/IOL implantation cases were successful. Most patients reported they were comfortable throughout the procedure. The success rate was high among patients who may be considered poor candidates for topical anesthesia; younger patients had more difficulty. This approach allows more patients to benefit from the advantages of topical anesthesia over other techniques.

Topical anesthesia for phacoemulsification: initial 20-case series with one month follow-up

We report the results of our initial 20 phacoemulsification cases performed using topical anesthesia. The preferred topical regimen consisted of preservative-free 0.75% bupivacaine. Intravenous sedation was provided primarily with fentanyl and midazolam. Phacoemulsification was performed through a scleral tunnel incision, and a one-piece poly(methyl methacrylate) or three-piece silicone intraocular lens was implanted. There were no complications with the anesthetic technique. One day postoperatively, 69% of patients with a desired refractive error within 0.75 diopters of emmetropia had an uncorrected visual acuity of 20/40 or better. At one month, all patients had a best corrected acuity of 20/30 or better, and 60%, 20/20 or better. Eighteen patients reported complete intraoperative comfort, and 17 reported complete postoperative comfort. Seven of the 10 patients who had had previous peribulbar anesthesia preferred topical. All 10 "first eye" patients said they would choose topical anesthesia for future surgery. With appropriate case selection, topical anesthesia for phacoemulsification surgery can be used with excellent intraoperative and postoperative results.