Evaluation of hemifield sector analysis protocol in multifocal visual evoked potential objective perimetry for the diagnosis and early detection of glaucomatous field defects.

PURPOSE: Multifocal visual evoked potential (mfVEP) is a newly introduced method used for objective visual field assessment. Several analysis protocols have been tested to identify early visual field losses in glaucoma patients using the mfVEP technique, some were successful in detection of field defects, which were comparable to the standard automated perimetry (SAP) visual field assessment, and others were not very informative and needed more adjustment and research work. In this study we implemented a novel analysis approach and evaluated its validity and whether it could be used effectively for early detection of visual field defects in glaucoma. METHODS: Three groups were tested in this study; normal controls (38 eyes), glaucoma patients (36 eyes) and glaucoma suspect patients (38 eyes). All subjects had a two standard Humphrey field analyzer (HFA) test 24-2 and a single mfVEP test undertaken in one session. Analysis of the mfVEP results was done using the new analysis protocol; the hemifield sector analysis (HSA) protocol. Analysis of the HFA was done using the standard grading system. RESULTS: Analysis of mfVEP results showed that there was a statistically significant difference between the three groups in the mean signal to noise ratio (ANOVA test, p < 0.001 with a 95% confidence interval). The difference between superior and inferior hemispheres in all subjects were statistically significant in the glaucoma patient group in all 11 sectors (t-test, p < 0.001), partially significant in 5 / 11 (t-test, p < 0.01), and no statistical difference in most sectors of the normal group (1 / 11 sectors was significant, t-test, p < 0.9). Sensitivity and specificity of the HSA protocol in detecting glaucoma was 97% and 86%, respectively, and for glaucoma suspect patients the values were 89% and 79%, respectively. CONCLUSIONS: The new HSA protocol used in the mfVEP testing can be applied to detect glaucomatous visual field defects in both glaucoma and glaucoma suspect patients. Using this protocol can provide information about focal visual field differences across the horizontal midline, which can be utilized to differentiate between glaucoma and normal subjects. Sensitivity and specificity of the mfVEP test showed very promising results and correlated with other anatomical changes in glaucoma field loss.

The role of hemifield sector analysis in multifocal visual evoked potential objective perimetry in the early detection of glaucomatous visual field defects.

OBJECTIVE: The purpose of this study was to examine the effectiveness of a new analysis method of mfVEP objective perimetry in the early detection of glaucomatous visual field defects compared to the gold standard technique. METHODS AND PATIENTS: Three groups were tested in this study; normal controls (38 eyes), glaucoma patients (36 eyes), and glaucoma suspect patients (38 eyes). All subjects underwent two standard 24-2 visual field tests: one with the Humphrey Field Analyzer and a single mfVEP test in one session. Analysis of the mfVEP results was carried out using the new analysis protocol: the hemifield sector analysis protocol. RESULTS: Analysis of the mfVEP showed that the signal to noise ratio (SNR) difference between superior and inferior hemifields was statistically significant between the three groups (analysis of variance, P < 0.001 with a 95% confidence interval, 2.82, 2.89 for normal group; 2.25, 2.29 for glaucoma suspect group; 1.67, 1.73 for glaucoma group). The difference between superior and inferior hemifield sectors and hemi-rings was statistically significant in 11/11 pair of sectors and hemi-rings in the glaucoma patients group (t-test P < 0.001), statistically significant in 5/11 pairs of sectors and hemi-rings in the glaucoma suspect group (t-test P < 0.01), and only 1/11 pair was statistically significant (t-test P < 0.9). The sensitivity and specificity of the hemifield sector analysis protocol in detecting glaucoma was 97% and 86% respectively and 89% and 79% in glaucoma suspects. These results showed that the new analysis protocol was able to confirm existing visual field defects detected by standard perimetry, was able to differentiate between the three study groups with a clear distinction between normal patients and those with suspected glaucoma, and was able to detect early visual field changes not detected by standard perimetry. In addition, the distinction between normal and glaucoma patients was especially clear and significant using this analysis. CONCLUSION: The new hemifield sector analysis protocol used in mfVEP testing can be used to detect glaucomatous visual field defects in both glaucoma and glaucoma suspect patients. Using this protocol, it can provide information about focal visual field differences across the horizontal midline, which can be utilized to differentiate between glaucoma and normal subjects. The sensitivity and specificity of the mfVEP test showed very promising results and correlated with other anatomical changes in glaucomatous visual field loss. The intersector analysis protocol can detect early field changes not detected by the standard Humphrey Field Analyzer test.

Prevalence and causes of blindness, low vision and status of cataract in 50 years and older citizen of Qatar-a community based survey.

BACKGROUND: Rapid Assessment for the Avoidable Blindness (RAAB) was conducted in Qatar during 2009. We present the prevalence and determinants of visual disabilities and status of cataract among citizens aged 50 years and older. METHODS: Residents of randomly selected houses and clusters participated in the survey. Opticians noted the presenting and the best corrected vision of participants from 49 clusters. Ophthalmologists examined participants with additional instruments like bio-microscope, digital camera, auto-perimeter and auto-refractor in a mobile van. World Health Organization recommended principal cause of blindness (Visual acuity [VA] < 3/60 in better eye), Severe visual impairment (SVI) (<6/60), low vision (VA < 6/18) and unilateral blindness (VA < 3/60) were designated. Persons with VA < 6/18 and cataract were interviewed to calculate coverage and barriers for cataract surgeries. Age sex adjusted prevalence of visual disabilities and their 95% Confidence Intervals (CI) were estimated. RESULTS: We examined 2,433 (97.3%) participants. The age sex adjusted prevalence of bilateral blindness was 1.28% [95% CI 1.22-1.35], SVI (1.67%), low vision (3.66%) and unilateral blindness (3.61%) in 50 years and older population. Female and older age groups were significant risk factors of visual disabilities. Cataract and glaucoma were the main causes of visual disabilities. The coverage of cataract services was 68.2%. Believing that cataract as an aging process (25) and adequate vision in the fellow eye (15) were the reasons for delay in surgery. CONCLUSIONS: To reduce avoidable blindness, un-operated cataract should be addressed. Primary and secondary eye care systems should be strengthened to improve the care of blinding eye diseases in Qatar.

Dexmedetomidine during local anesthesia.

The objective of our study was to assess the efficacy and safety of dexmedetomidine given in a small dose for a 1-h infusion as an adjuvant to local analgesia in ophthalmic operations. The study was double-blind prospective, randomized, and placebo controlled. We studied the effects of a small dose of dexmedetomidine (0.5 micro.kg(-1).h(-1) for 10 min followed by 0.2 micro.kg(-1).h(-1) for 50 min. Patients were divided randomly into two groups with 20 patients in each: group A was the study group and group B was the placebo group. Heart rate, systolic blood pressure, and diastolic blood pressure were significantly lower in the dexmedetomidine group than the placebo group. Bispectral index values were significantly lower in the dexmedetomidine group than the placebo group. Also, intraocular pressure significantly decreased in the dexmedetomidine group compared to the placebo group. The study revealed that dexmedetomidine in the studied dose has a sedative effect, provides safe control of heart rate and blood pressure, and also decreases intraocular pressure during ophthalmic surgery under local anesthesia.

Determinants of women's choice of their obstetrician and gynecologist provider in the UAE.

BACKGROUND: The objective of this study is to evaluate women's priorities and preferences in selecting their obstetrician and gynecologist in a non-Western society. METHODS: Consecutive sample of 508 patients attending the obstetric and gynecologic services of AL-Ain Hospital; AL-Ain; United Arab Emirates during 4 months was recruited. Participants were interviewed by using a structured 26-item questionnaire administered by means of face-to-face interview within 24 h of admission in the ward or before consultation in the outpatient clinic. Respondents were asked about their preferences, priorities, determinants of choice of their obstetrician and gynecologist, their view of his/her role as a medical provider, and their perception of importance of each of provider's characteristics and roles on a five-point Likert scale. RESULTS: Four hundred thirty-nine (86.4%) participants preferred female physicians. Sixty-one (12%) had no preference and eight (1.6%) preferred male physicians. Reasons for female selection were privacy during intimate examination (89.1%) or counseling (68.8%), religious beliefs (74.3%), and cultural traditions (45.3%). Female preference was significantly associated with higher parity (P = 0.002), religion (P = 0.005), nationality (P = 0.01), occupation (P = 0.02), education (P = 0.04), and poor recognition of physician's role as professional/expert (P < 0.00001). Male preference was significantly associated with experience at previous encounter (P = 0.03), obstetric consultation (P = 0.04), and perceiving physician's role as skilled communicator (P = 0.01) or health educator (P = 0.04). Other physician characteristics affecting choice were professionalism, bedside manners, empathy, communication, competence, availability, and religion. CONCLUSIONS: Physician's attitude, professional profile, sex, and religious faith determine women's choice of obstetricians and gynecologists. Most women prefer female providers because of embarrassment during pelvic examination and reproductive counseling, religious beliefs, and sociocultural values.