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At least 1,693 records · Page 94Linked to original sources
PubMed1989

Do optometrists screen for glaucoma?

A survey of optometrists practising in Nottingham was undertaken to identify their methods of screening for glaucoma in the community. There was found to be great variation in all parameters examined including referral criteria. Although all of the respondents screened for glaucoma, 50% appeared not to be aware of subtle optic disc signs of the disease, 8% never measured intra-ocular pressures and 19% never performed visual field analysis. In a general practice population age 50 and over, 73% of patients had visited their optician within the last two years, 67% knew glaucoma was an eye disease, but only 15% remembered being screened for glaucoma.

False Positive Reactions↗
PubMed1991

Low vision aids--is our service cost effective?

A questionnaire and telephone survey was carried out on a Scottish population of patients with impaired vision, in order to ascertain the proportion of patients who gain benefit from Low Vision Aids (LVA) and to determine the number of LVAs which are retained but unused. One third of the patients who answered the questionnaire never use their LVAs, and one half were not satisfied with the service provided. A cost analysis indicated that approximately (pounds) 8,000 worth of LVAs are neither used nor returned each year to a single LVA service. The patients' ages, diagnoses, and visual acuities were related to the compliance rate. It appears that increasing age and decreasing visual acuity may be factors which decrease compliance. However none of the factors analysed could be used as a reliable predictor of patient satisfaction or of eventual benefit. Other health services which provide intensive training in the use of LVAs reportedly achieve a higher level of compliance. We conclude that our present service could probably be improved by the employment of additional staff specifically trained to teach patients how to make best use of the LVAs provided.

Adolescent↗
PubMed1991

An analysis of the accuracy of prediction of intraocular implant power in the myopic patient.

A series of 90 eyes of 88 myopic patients who underwent extracapsular cataract surgery with intraocular lens implants (IOLs) between 1984 and 1989 were analysed in a retrospective study. The axial length as obtained by ultrasonic A scan and keratometry readings were applied to the SRK1 and modified SRK (SRK2) formulae and the result compared with the actual post-operative state achieved.

Cataract Extraction↗
PubMed1991

The reproducibility of biometry and keratometry measurements.

Axial length and corneal curvature are entered into formulae to calculate intraocular lens power for cataract surgery and the absolute measurement of fundus structures such as neuroretinal rim area in glaucoma. The reproducibility (coefficient of variation, CV) of biometry and keratometry was investigated by taking five measurements of thirty phakic eyes. Although both techniques were found to be highly reproducible (CV less than 1%), keratometry was the more so. However, a clinically significant difference was noted between the first and the mean of five readings for both biometry (0.15 +/- 0.05 mm) and keratometry (0.05 +/- 0.03). Taken together, these errors would result in a postoperative refractive error of 0.65D using the SRK formula. Measurement errors were just as likely to occur with short or long eyes. Similar results were found when the analysis was performed on three measurements of both axial length and corneal curvatures. We recommend taking the average of three biometry and keratometry readings to improve the reliability of the techniques, and to increase the accuracy of calculating intraocular lens power and fundus structure dimensions.

Biometry↗
PubMed1991

Comparative analysis of three prospective trials of multifocal implants.

A clinical analysis of best cases four to 12 months postoperatively was made to assess the function of 47 3M multifocal implants, 40 Iolab multifocal implants and 24 AMO multifocal implants. Overall 86 (79%) eyes could see 6/12 and N6 unaided. The multifocal function for each lens worked well for distance, intermediate and near in the majority but an increase in depth of field was at a cost of reduced resolution efficiency. The 3M lens was associated with symptoms of poor optical quality in 29.8% and with an inability to read N5 with correction in 17%. The Iolab lens provided better reading vision but less good distant vision than the other types and was associated with symptoms of poor optical quality in 15%. Many of these had a pupil diameter greater than 3.5 mm. The AMO lens gave a poorer unaided reading vision than the other lens types but had the lowest incidence of optical symptoms.

Humans↗
PubMed1992

Clinical comparison of automated and manual keratometry in pre-operative ocular biometry.

Corneal measurements, using the manual (Topcon OM-4) and automated (Canon RK-1) keratometers was performed on 104 eyes of 104 patients undergoing cataract and implant surgery to assess the role of automated keratometry in pre-operative ocular biometry. Four eyes of four patients were excluded from statistical analyses for various reasons. The time taken to perform automated keratometry was a mean of 61 (SD 21) seconds compared to 205 (SD 37) seconds for manual keratometry; the difference was statistically significant (p < 0.001). In terms of the various keratometry values compared, mean K (corneal refractive power), flattest K, steepest K, astigmatism and the axis of astigmatism, 65% to 75% of the cases on automated keratometry were within 0.26 dioptres or 11 degrees of manually determined values; the difference was statistically significant (p < 0.001). Although automated keratometry was significantly quicker than manual keratometry, we continue to use manual keratometry values for intraocular lens power calculations as the accuracy demonstrated by automated keratometry was considered inadequate for this purpose.

Aged↗
PubMed1996

Comparison between an ophthalmic optician and an ophthalmologist in screening for diabetic retinopathy.

The best method of screening for diabetic retinopathy is still debated: fundus photography, general practitioners, hospital physicians and ophthalmic opticians have been advocated. This study compared the performance of an ophthalmic optician with an ophthalmologist, both using mydriatic and slit lamp biomicroscopy and direct ophthalmoscopy. A total of 474 eyes of diabetics in a single group practice were examined by both practitioners at their annual check. There was total agreement about presence or absence of retinopathy in 366 eyes (77%). Although the optician diagnosed less background diabetic retinopathy (83 versus 123 eyes) and diabetic maculopathy (47 eyes versus 63 eyes), he would have referred 20 of 26 eyes with moderate or severe maculopathy and 33 of 36 eyes with moderate or severe background retinopathy: sensitivities of 0.77 and 0.92 respectively. This compares favourably with previous studies and we suggest that ophthalmic opticians with suitable training would be an effective body to screen for diabetic retinopathy.

Clinical Competence↗
PubMed1996

Preventable delays in the treatment of intraocular melanoma in the UK.

Intraocular melanoma should be treated urgently to improve the chances of survival and of conserving the eye and vision. The aims of this study were to determine the mode of presentation of intraocular melanoma in the United Kingdom and to identify any preventable causes of delay in treatment. A total of 112 patients were included and questioned about their initial symptoms, the type of practitioner consulted and their subsequent management. Thirty per cent of patients were asymptomatic and detected on routine ophthalmoscopy. Symptomatic patients presented with blurred vision (52%), photopsia (26%), visual field loss (9%) and miscellaneous symptoms (13%). Patients presented to an optometrist in 66 cases (59%), to a general practitioner in 30 cases (27%) and to an ophthalmologist in 16 cases (14%). The tumour was misdiagnosed in 12% of patients presenting to an optometrist and in 27% of cases presenting to a GP. The period from the time of onset of symptoms or detection of an abnormality to the time when the patient was referred to the Ocular Oncology Service averaged 6 months (range 0-36 months). Patients waited an average of 4 months if referred urgently as compared with 7.7 months if referred non-urgently (Mann-Whitney U-test, p = 0.0003). Patients were likely to be treated sooner if they were referred directly to the ophthalmologist rather than via the GP (7.8 months vs 4.8 months; Mann-Whitney U-test, p = 0.02).

Adult↗
PubMed1997

Astigmatism decay immediately following suture removal.

In a prospective study of 34 patients with high post-operative astigmatism (mean 6.90 D, range 2.75-15.00 D) following extracapsular cataract surgery (13 limbal sections and 21 corneal sections), we used keratometry to assess the changes in corneal curvature seen within 30 minutes of suture removal and compared these with the astigmatism found 2 weeks later. The greatest change occurred within the first 5 minutes of suture removal (mean 3.63 D; 95% confidence interval (95% CI) 2.85-4.41). The rate of decay then declined so that between 15 and 30 minutes the mean change was 0.56 D (95% CI 0.43-0.69). At 2 weeks a further mean decay of 1.29 D (95% CI 0.99-1.61) occurred. Of the 6 patients exhibiting a residual astigmatism greater than 3.00 D at 30 minutes, 4 continued to do so 2 weeks later. Our study suggests that keratometry 30 minutes following suture removal is only moderately different from that seen 2 weeks later. Although not stable enough to suggest that patients could be routinely refracted within 30 minutes of suture removal, in cases where early visual recovery is essential, such as in monocular patients, it may be reasonable to offer a temporary spectacle correction immediately following suture removal. Furthermore keratometry at 30 minutes after suture removal accurately predicts the necessity for further removal of sutures and indicates which patients can be discharged to the care of their own optometrist, making a further hospital visit unnecessary.

Aged↗
PubMed1997

Clinical assessment of a hand-held automated keratometer in cataract surgery.

PURPOSE: Pre-operative keratometry was performed on 32 eyes of 32 patients undergoing extracapsular cataract extraction with intraocular lens implantation, for calculation of intraocular lens power. In an additional 20 eyes of 20 patients post-operative keratometry was performed to guide selective suture removal. Readings from a manual keratometer and an automated hand-held keratometer were compared. METHODS: Pre-operative measurements were repeated three times on each subject to assess the repeatability of each machine. Mean-difference plots were performed to define the limits of agreement of the two machines. RESULTS: Repeatability was higher using manual keratometry (MK) than automated keratometry (AK). There was broad agreement between the two machines in pre-operative and post-operative assessment, although clinically significant differences are likely to occur in some cases. CONCLUSIONS: MK should continue to be used for routine pre-operative keratometry, with the AK providing a useful alternative when MK is not possible. AK is sufficiently accurate to allow its use in post-operative assessment of suture-induced astigmatism.

Astigmatism↗
PubMed1998

The changing pattern of glaucoma referrals by optometrists.

PURPOSE: To identify any change in optometric referral patterns for suspect glaucoma over a 5 year period. METHOD: A retrospective analysis was carried out of referrals for suspect glaucoma to a hospital glaucoma clinic from 1988 and 1993. RESULTS: There was a significant decrease in the positive referral rate with time from 56% in 1988 to 37% in 1993 (p = 0.02). Intraocular pressures (IOPs) of all patients prior to referral and at presentation to the glaucoma clinic were significantly higher in 1988 (25.1 and 25.6 mmHg respectively) than in 1993 (22.4 and 23.0 mmHg respectively, p < 0.0005). However, the presenting IOPs of eyes with glaucoma were similar in the cohorts (27.5 vs 26.4 mmHg, p = 0.33). Prior to referral, optometrists performed visual fields on 28% of patients in 1988 and on 48% in 1993 (p 0.01), giving an estimate of the cup/disc ratio in 15% of patients in 1988 and 41% in 1993 (p = 0.0004). CONCLUSIONS: The increased false positive referral rate appears to be associated with the increasing use of visual field analysers by optometrists and a willingness to refer at lower IOPs. Increased false positive referrals result in increased waiting times for hospital assessment.

England↗
PubMed1998

Glaucoma screening by optometrists: positive predictive value of visual field testing.

PURPOSE: Visual field testing is increasingly being performed by optometrists in order to improve glaucoma detection. The aim of this study was to assess the positive predictive value (PPV) of visual field testing as currently practised by optometrists. METHODS: A retrospective study was performed of referrals for suspected glaucoma to an ophthalmology department during a 3 month period. The PPV for glaucoma was determined according to the reason for referral. RESULTS: There were 86 referrals for suspected glaucoma. Isolated field loss accounted for 12% of these referrals but no cases of glaucoma detection. These subjects were either false positive referrals or had field defects of nonglaucomatous aetiology (tilted optic disc and porencephalic cyst). The PPV for glaucoma among referrals with isolated field loss was significantly less than that among referrals with field loss in association with corroborative abnormalities (0 vs. 60%, p = 0.005). No such difference was found for referrals with raised intraocular pressure (43% vs. 57%, p = 0.38) or suspicious discs (25% vs. 53%, p = 0.60). CONCLUSIONS: Visual field testing is currently leading to unnecessary referrals to the hospital eye service with no detectable improvement in the accuracy of glaucoma suspect referrals. It is important that optometrists perform visual field testing in accordance with validated screening methodology.

Adult↗
PubMed1998

Measurement of axial length in the calculation of intraocular lens power.

PURPOSE: Accurate measurement of ocular axial length is essential for accurate intraocular lens (IOL) power calculation. Although it is common practice to average several axial length measurements to improve accuracy, it has been suggested that a single high-quality A-scan ultrasonographic measurement is adequately accurate owing to the high test-retest reliability of A-scan biometry. The aim of this study was to compare the accuracy of a single high-quality A-scan measurement with that of the average of three acceptable measurements in the calculation of IOL power. METHOD: We studied 103 eyes of 103 patients who underwent cataract-IOL surgery. All these patients underwent pre-operative ocular biometry, a standardised extracapsular cataract extraction with posterior chamber IOL implantation, and clinical refraction between 10 and 14 weeks post-operatively. RESULTS: There was no statistically significant difference between the two study groups in measured axial length (p > 0.01), calculated emmetropic IOL power (p > 0.05) or the prediction of post-operative refraction (p > 0.99). CONCLUSION: The use of a single high-quality axial length measurement was as accurate as the mean of three acceptable axial length measurements in the calculation of IOL power.

Cataract Extraction↗
PubMed1998

Optimisation of outpatient resource utilisation in cataract management.

PURPOSE: We assessed whether patients referred with a diagnosis of cataract require outpatient assessment before listing for surgery or whether the general practitioner could have direct access to the waiting list. We also studied whether pre-assessment clinics made a significant difference to management even when waiting times were long. METHODS: Data about patients referred with a diagnosis of cataract to the Oxford Eye Hospital and associated hospitals were collected. Seventy-five patients were prospectively studied and 100 patient records were retrospectively analysed. RESULTS: Twenty-six per cent of patients had a misdiagnosis or additional problems affecting management. Optometrists provided more information than general practitioners, but their diagnostic accuracy was equal (73% optometrists, 75% general practitioners). At the pre-assessment clinic pupil dilatation changed management in only 4% of patients. CONCLUSION: Listing patients on the basis of referral letters would be inappropriate in 1 in 4 patients. Pre-assessment clinics rarely picked up a clinically relevant change. Thus if outpatient consultation included a decision on the exact surgical plan including implant power, then pre-assessment clinics may not be necessary.

Cataract↗
PubMed2000

Cataract surgery and the optometrist.

PURPOSE: To determine the outcome of discharge on the first day following cataract surgery and the feedback from patients' optometrists. METHODS: Casenotes of patients who had cataract surgery between 1 April 1997 and 30 June 1998 were analysed. Patients without complications were discharged on day 1 and advised to see their optometrist at 1 month. Patients were given a form for refraction with a pre-paid envelope for their optometrist. Completed letters from the optometrists were returned to the hospital to be analysed by the principal surgeon and acted on appropriately. A questionnaire was sent out to patients whose notes did not contain any information after the first post-operative examination. RESULTS: A total of 318 eyes from 288 patients underwent cataract surgery. Completed forms from the optometrist were received in 245 (77%) cases; no optometrist's letter was found in the remaining 73 cases (23%). Of these 73 patients, 50 (68%) had other ocular pathology requiring hospital follow-up and 9 had died. There were only 6 patients about whom post-operative information could not be obtained. There were no significant differences regarding the age and sex of those who did or did not attend the optometrist. CONCLUSION: Patients without complications can be discharged to the care of their optometrist on the first day following cataract surgery. With good communication between hospital and the optometrist, better use can be made of available resources.

Aftercare↗
PubMed2000

CJD and the eye.

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Creutzfeldt-Jakob Syndrome↗