Scanning electron microscopy of the monkey eye in miosis and mydriasis.

The structure of the iris, trabecular meshwork and the course and insertion of the zonular fibres have been examined in extreme miosis and maximal mydriasis of the monkey eye, using scanning electron microscopy. The iris showed pronounced differences in its posterior surface and in the shape of the posterior epithelial pupillary edge; in the course of the fibroblast-and melanocyte-processes in the pupillary area; and in the shape of the posterior epithelial layer and the course of vessels and melanocytes in radial as well as in tangential sections. Some difference was noticed in the width of the gaps at the anterior iris surface but no difference was seen in shape and density of the stromal collagen fibres. The trabecular sheets are spaced wider apart in miotic than mydriatic eyes, as seen through pores of meshworks that were left intact or meshworks that had been cut either circumferentially or meridionally; but a difference in the shape of the lamellar holes was not apparent. The ciliary processes frequently show a single crest in mydriasis and twin crests in miosis. The zonular fibres originate from the pars plana and insert into the lens by means of but two sets of fibres, anterior and posterior zonular fibres. These fibres do not cross; most fibres pass the ciliary processes though some fibres may adhere to valleys or crests being presumably vestigial of artefactual. The posterior zonular fibres insert into the posterior capsule forming a single circular rim, in front of the insertion of the anterior hyaloid membrane. The anterior zonular fibres insert circumferentially into the anterior capsule in two or three rows. All fibres insert axially to the equator of the lens and so-called equatorial fibres do not exist. With the present method, no difference could be demonstrated between the zonular fibres in miosis and mydriasis.     

Effects of pupillary dilation on automated perimetry in normal patients

The effects of pupillary dilation (tropicamide 1%) on automated static threshold perimetry were studied in 18 normal subjects using the Humphrey field analyzer 30-2 and STATPAC programs. The mean defect worsened by 0.83 decibels (standard deviation, 0.92 decibels) in dilated fields as compared with baseline visual fields (P = 0.001). These findings indicate that pupillary dilation in healthy subjects who are not receiving ocular medications produces statistically significant declines in threshold sensitivities. Valid comparison of results from serial visual field testing, therefore, depends on control of or adjustment for the effect of pupillary dilation.     

Effects of pupillary constriction on automated perimetry in normal eyes

The authors studied the effects of pupillary constriction (pilocarpine 2%) on automated static threshold perimetry in 20 normal subjects using the Humphrey Field Analyzer 30-2 and STATPAC programs. The mean defect (MD) worsened by an average of 0.67 decibels (dB) (standard deviation, 0.67 dB) in constricted fields compared with baseline visual fields (P less than or equal to 0.001). Independent comparisons of the unweighted means of threshold values for the central 30 degrees, 24 degrees, and 10 degrees were also done and showed significant reductions in sensitivity after constriction (P less than or equal to 0.001). These findings indicate that changes in pupillary diameter may produce significant declines in threshold sensitivities and support the importance of consistent pupillary diameters on serial automated visual field examinations.     

Recent developments in kinetic perimetry

The manual kinetic perimetry using Goldmann instrument is still widely used and remains a "gold standard" in examining patients with any kind of advanced visual field loss and impaired co-operability. Nevertheless, Goldmann instrument has several disadvantages, such as examiner dependence, response variability, lack of standardization of parameters, poor repeatability. The latest development in kinetic perimetry, which was realized at the University Eye Hospital in Tuebingen (Germany) is semi-automated kinetic perimetry (SKP), using Octopus 101 instrument (Interzeag/Haag-Streit, Koeniz-Bern, Switzerland). It is an examiner-independent, standardized and reproducible method. Additionally, obtained results can be corrected for the mean individual reaction time. This paper will briefly present characteristic, advantages and application of SKP in clinical practice.     

Hydroxyamphetamine mydriasis in normal subjects

Hydroxyamphetamine eyedrops are used to help localize the lesion in Horner's syndrome. Because normal variability in the response to the eyedrops may influence the interpretation of test results in patients with Horner's syndrome, we studied both the interocular variability of the drug's mydriatic effect within each normal subject and the variation between individuals. We used photographs to document the variability among 26 normal subjects. Hydroxyamphetamine hydrobromide 1% eyedrops (Paredrine) were placed in both eyes of normal subjects in the same way that patients with Horner's syndrome are tested. The drug produced a mean increase in pupil size of 1.96 mm (+/- 0.61 S.D.) in the 52 eyes tested. In normal subjects, the mydriatic effect of hydroxyamphetamine was symmetric in each pair of eyes. The mean interocular asymmetry of mydriasis as measured by the difference in dilation (right eye dilation minus left eye dilation) was -0.087 mm (+/- 0.29 S.D.). Thus, the variability of hydroxyamphetamine mydriasis from one eye to the other in a single subject was much lower than the variability between subjects.     

Feasibility and outcome of automated kinetic perimetry in children

Purpose  

Visual field testing in children is often performed using a Goldmann perimeter. Because the technique is performed manually, it is difficult to standardize, and stimuli are often presented too quickly. Automated kinetic perimetry has been successfully established in adults, but to date no results have been published in children. This paper describes the feasibility and outcome of automated kinetic perimetry in children in a standard clinical setting.     

Test-retest variability of frequency-doubling perimetry and conventional perimetry in glaucoma patients and normal subjects

PURPOSE: To compare the test-retest variability characteristics of frequency-doubling perimetry, a new perimetric test, with those of conventional perimetry in glaucoma patients and normal control subjects. METHODS: The study sample contained 64 patients and 47 normal subjects aged 66.16+/-11.86 and 64.26+/-7.99 years (mean +/- SD), respectively. All subjects underwent frequency-doubling perimetry (using the threshold mode) and conventional perimetry (using program 30-2 of the Humphrey Field Analyzer; Humphrey Instruments, San Leandro, CA) in one randomly selected eye. Each test was repeated at 1-week intervals for five tests with each technique over 4 weeks. Empirical 5th and 95th percentiles of the distribution of threshold deviations at retest were determined for all combinations of single tests and mean of two tests, stratified by threshold deviation. The influence of visual field eccentricity and overall visual field loss on variability also were examined. RESULTS: Mean test time with frequency-doubling perimetry in patients and normal control subjects was 5.90 and 5.25 minutes, respectively, and with conventional perimetry was 17.20 and 14.01 minutes, respectively. In patients, there was a significant correlation between the results of the two techniques, in the full field and in quadrants, whereas in normal subjects there was no such correlation. In patients, the retest variability of conventional perimetry in locations with 20-dB loss was 120% (single tests) and 127% (mean tests) higher compared with that in locations with 0-dB loss. Comparative figures for frequency-doubling perimetry were 40% and 47%, respectively. Variability also increased more with threshold deviation in normal subjects tested with conventional perimetry. In both patients and normal subjects, variability increased with visual field eccentricity in conventional perimetry, but not in frequency-doubling perimetry. Both techniques showed an increase in variability with overall visual field damage. CONCLUSIONS: Frequency-doubling perimetry has different test-retest variability characteristics than conventional perimetry and may have potential for monitoring glaucomatous field damage.     

A dissociation of thresholds between Goldmann kinetic perimetry and high-pass resolution perimetry in retinitis pigmentosa]

The authors studied the differences between the automated static perimetry of high-pass resolution perimeter (HRP) and the kinetic perimetry of the Goldmann perimeter in 12 patients with retinitis pigmentosa. In a total of 10 eyes of 6 patients, we found 19 quadrants in which the patients were not able to recognize the largest ring target even when the target was within the isopter of the Goldmann perimetry. Also, there were 10 quadrants in which the largest target was not recognized in a total of 6 eyes of 4 patients even though their visual field showed symmetrical isopter in upper and lower or right and left quadrants in the Goldmann perimetry. As a result, it was suggested that the causes of the dissocation were a greater decrease in sensitivity for the low spatial frequency target than the high spatial frequency target and/or a greater decrease in resolution sensitivity than light sensitivity in retinitis pigmentosa.     

Changes in the shape of the anterior and posterior corneal surfaces caused by mydriasis and miosis: detailed analysis

PURPOSE: To evaluate changes in the anterior and posterior corneal shape, corneal thickness, and anterior chamber depth (ACD) caused by mydriasis or miosis using scanning-slit corneal topography. SETTING: Department of Ophthalmology, Iwate Medical University School of Medicine, Iwate, Morioka, Japan. METHODS: Twenty-eight eyes of 28 healthy volunteers with refractive errors of -6.00 to +0.25 diopters were studied. One eye of each subject had instillation of tropicamide-phenylephrine hydrochloride (Mydrin P) to obtain mydriasis and of pilocarpine hydrochloride 2% (Sanpilo) to obtain miosis. To assess the corneal shape, the best-fit sphere (BFS), axial power, and tangential power were measured for the anterior and posterior corneal surfaces before and after mydriasis and before and after miosis using scanning-slit corneal topography (Orbscan version 3.0, Orbtek, Inc.). The pupil size, corneal thickness, and ACD were also examined before and after mydriasis and before and after miosis. RESULTS: The mean age of the patients was 31.1 years +/- 5.6 (SD) (range 20 to 46 years). The anterior BFS changed from a mean of 8.04 +/- 0.3 mm at the time of mydriasis to a mean of 8.00 +/- 0.3 mm at the time of miosis. The posterior BFS changed from 6.53 +/- 0.3 mm to 6.46 +/- 0.3 mm, respectively. Thus, the anterior and posterior cornea became significantly steeper after miosis (P<.01). The ACD was significantly more shallow after miosis than after mydriasis. However, there was no significant difference in corneal thickness after mydriasis or miosis. CONCLUSIONS: The anterior and posterior corneal shapes changed as a result of mydriasis and miosis, and the refractive power of the cornea significantly increased after miosis. To date, changes in refractive power from changes in pupil size have been attributed to a change in the refractive power of the crystalline lens; however, it is now thought that changes in corneal refractive power also occur.     

Comparison of pupil perimetry and visual perimetry in normal eyes: decibel sensitivity and variability

PURPOSE: To compare the sensitivity and variability of pupil perimetry with visual perimetry at the same retinal locations in normal subjects. METHODS: Pupil perimetry was performed on the right and left eyes of 10 normal subjects using a computerized infrared pupillometer equipped to present perimetric light stimuli and record pupil light reflexes. Eleven locations were tested at different intensities along the horizontal meridian of each eye, and the decibel sensitivity of the pupil light reflex was compared with the visual threshold at the same location. RESULTS: The shape and height of the hill of vision (retinal sensitivity) was very similar between the right and left eyes of each individual using either pupil perimetry (R2 = 0.69) or standard threshold perimetry (R2 = 0.62) but was less similar between subjects. Comparisons between pupil and visual sensitivity revealed a lack of correlation at the same retinal location in normal eyes (R2 = 0.19). CONCLUSIONS: The high intereye correlation for either pupil or visual sensitivity may provide an important tool for detecting focal or asymmetric visual field damage. Although the basic shape of the sensitivity profile of pupil and visual responses was similar under the conditions of testing, the two did not correlate well within each eye among the normal subjects. This highlights that similarities do exist in the sensitivity profile of the two pathways, but they do not seem to vary in the same proportion between normal individuals.     

Visual field assessment in glaucoma: comparative evaluation of manual kinetic Goldmann perimetry and automated static perimetry

PURPOSE: To compare the detection and assessment of progression of visual field defects in primary open-angle glaucoma with manual suprathreshold perimetry on Goldmann perimeter and automated static threshold perimetry on Humphery visual field (HVF) analyzer. METHODS: 105 eyes of 54 patients of primary open-angle glaucoma were followed up with 3-monthly perimetry on Goldmann perimeter and HVF analyzer, for a period of 9 months. RESULTS: HVF analyzer picked up visual field defects in 48 (46%) eyes whereas Goldmann perimeter picked up visual field defects in 26 (25%) eyes. HVF analyzer demonstrated progression in 14 eyes whereas Goldmann perimeter detected progression in 7 eyes during follow up of 9 months. CONCLUSIONS: HVF analyzer is superior to Goldmann perimeter to document and to demonstrate progression of visual field defects in primary open-angle glaucoma.     

中心视野检查联合周边视野检查在青光眼诊断中的价值

目的探讨中心视野检查联合周边视野检查是否能减少青光眼诊断的漏诊率。方法病例组（青光眼患者）84例（165只眼）与对照组（按性别、年龄、文化程度与病例组相配比的正常人群）110例（220只眼）分别使用Octopus101自动电脑视野计进行中心视野检查和周边视野检查,将中心视野检查及中心与周边视野检查的联合结果请三位医生在盲法的情况下独立进行分析评价,最后将评价结果进行统计学的分析,计算出漏诊率。结果病例组中中心视野检查结果异常的有129只眼,而中心视野检查联合周边视野检查结果异常的有153只眼;对照组中中心视野检查结果异常的有17只眼,而中心视野检查联合周边视野检查结果异常的有36只眼。将其中的中心视野检查结果与联合视野检查结果相比较,使用SPSS11.5统计软件进行分析可知：中心视野检查联合周边视野检查漏诊率为7.3%,单独的中心视野检查的漏诊率为21.8%,P=0.000〈0.05,具有统计学意义。结论使用Oc-topus101自动电脑视野计中心视野检查联合周边视野检查能减少青光眼诊断的漏诊率。     

正常人蓝/黄视野和白/白视野的阈值变异性比较

目的:比较正常人蓝/黄(B/Y)视野检查法和白/白(W/W)视野检查法阈值的短期波动、长期波动及个体间变异。方法:应用Octopus101全自动视野计对22￣29岁正常人22例22眼进行B/Y视野检查及W/W视野检查,检测2种视野阈值的短期波动、长期波动及个体间变异,并对短期波动均值、平均阈值长期波动均值及平均阈值的个体间变异进行比较;对B/Y视野1～59个点的阈值长期波动进行分析。结果:B/Y视野检查法的短期波动(1.81±0.28)dB,平均阈值的长期波动(2.64±1.25)dB,均大于W/W视野检查法(1.34±0.21)dB,(1.37±0.78)dB,差异有显著性意义(t=6.60,P<0.001)和(t=4.22;P<0.001);B/Y视野检查法的个体间变异大于W/W视野检查法,差异有显著性意义(F=39.44;41.24;75.37;90.67;均为P<0.0001)。B/Y视野1～59个点阈值长期波动随离心度的增加而增大,呈正相关关系(r=0.4613,P<0.05),上方象限29个点阈值的长期波动(4.41±2.48)dB大于下方象限29个点的长期波动(3.84±2.48)dB,比较有显著意义(t=3.68;P<0.001)。结论:B/Y视野检查法的正常人的阈值变异较W/W视野检查法大,需要有更大的正常值范围。在评估B/Y视野的结果时,应考虑阈值改变的位置和程度,必要时重复检测。常规的W/W视野检查应保留对青光眼的诊断和随访。