Types Of Visual Field Defects Research Articles

Scleral edge, not optic disc or retina, is the primary site of injury in chronic glaucoma

In chronic glaucoma, there is a gradual painless loss of vision, early manifestation of arcuate field defect and typical atrophy of the optic disc known as 'cupping'. Chronic glaucoma is classified into high-tension glaucoma (HTG) and normal-tension glaucoma (NTG). Although both types manifest with the same typical visual field defect and cupping of the optic disc, high-tension glaucoma has elevated intraocular pressure whereas in normal-tension glaucoma the intraocular pressure (IOP) is within the normal range (10-21 mmHg). There are several theories about the pathogenesis of chronic glaucoma ranging from high intraocular pressure directly damaging the optic disc to programmed death(apoptosis) of the ganglion cells of the retina. But none of them satisfactorily explain the manifestation of the early arcuate field defect which is a pathognomonic feature of both types of chronic glaucoma. This article focuses on two main issues. First, how and why the arcuate field defects are produced in the early stages of glaucoma and secondly to find out the common ground in the pathogenesis of both high and normal tension glaucoma. The early arcuate field defects are an important lead in discovering the pathogenesis of glaucoma, therefore if any factor or site which could not possibly produce initial sharply defined arcuate field defects was ruled out. This article presents an unconventional approach to the pathogenesis of glaucoma. Instead of looking for various factors causing glaucoma, emphasis was placed on determining the primary site of injury which could produce the initial arcuate field defects. Keeping the arcuate visual field defects in mind, the primary site of injury appears to be at the scleral edge and not the optic disc or the retina in chronic glaucoma. The border tissue which separates the sclera and choroid from the nerve fibers would atrophy due to chronic ischemia as a result of high intraocular pressure in HTG, whereas due to poor systemic circulation in NTG. In both types of chronic glaucoma, the ciliary circulation supplying the prelaminar and border tissue is compromised. As a result of atrophy of the border tissue, the optic disc sinks as a whole beginning temporally due to its tilted position and causing nerve fibers to stretch, kink, and cut at the scleral edge. This process of optic disc sinking would accelerate due to loss of nerve fibers which also provides anchorage to the optic disc. This cycle would continue until all the nerve fibers are cut at the scleral edge and the optic disc is destroyed.

Visual Field Abnormalities in Nonarteritic Anterior Ischemic Optic Neuropathy

To evaluate the pattern of various types of visual field defects and their prevalence at initial examination of nonarteritic anterior ischemic optic neuropathy (NA-AION). The data were compiled from 312 consecutive eyes (in 265 patients) that fulfilled our inclusion and exclusion criteria. A comprehensive ophthalmic evaluation was performed, including recording of visual acuity, visual fields with a Goldmann perimeter (using I-2e, I-4e, and V-4e targets regularly), and intraocular pressure; slitlamp examination of the anterior segment; ophthalmoscopy; color fundus photography; and in acute cases, fluorescein fundus angiography. The visual field defects were divided into 2 groups: (1) general field defects and (2) various types of scotoma in the central 30 degrees . The prevalence of various types of visual field defects was estimated for I-2e, I-4e, and V-4e isopters by dividing the total number of eyes with the defect by the total number of eyes that could see that particular target. Exact 95% confidence limits for the prevalence were computed. Of the 265 patients, 169 (63.7%) were male and the mean +/- SD patient age was 55.0 +/- 9.1 years. The median interval between the first visual field test and the onset of NA-AION was 2 weeks. Of the 312 eyes, the I-2e target was seen by 75.3%, the I-4e target by 90.7%, and the V-4e target by 100%. Overall prevalence of general visual field defects was 83.4% with I-2e, 78.8% with I-4e, and 68.9% with V-4e, whereas the prevalence of scotoma(s) within the central 30 degrees was 55.3%, 49.5%, and 36.2%, respectively. Central scotoma was seen in 48.5% with I-2e, 43.8% with I-4e, and 29.2% with V-4e. A detailed prevalence of various types of visual field defects is given. Relative inferior altitudinal defect was most common (34.9% with I-2e and 22.3% with I-4e), but the absolute inferior altitudinal defect was seen in only 8.0%. By contrast, absolute inferior nasal sector visual loss was the most common defect detected in NA-AION (22.4%), but it occurred in only 3.4% with I-2e and 11.0% with I-4e. Overall, loss of the nasal part of the visual field was the most common occurrence. Our study demonstrated that NA-AION eyes may initially show a variety of optic nerve-related visual field defects. Our study also showed that an absolute inferior nasal visual field defect is much more common (22.4%) than an absolute inferior altitudinal visual field defect (8.0%) in NA-AION and could be considered the most characteristic single field defect in NA-AION. We found that a combination of relative inferior altitudinal defect with absolute inferior nasal defect is usually the most common pattern in NA-AION.

Posterior ischaemic optic neuropathy: clinical features, pathogenesis, and management

To investigate and present a comprehensive account of the clinical features, pathogenesis, and management of posterior ischaemic optic neuropathy (PION). This retrospective study is based on 53 consecutive eyes of 42 patients with PION seen in my clinic since 1973, who fulfilled the inclusion criteria. They were systematically evaluated, treated, and followed by me. All patients had initially detailed ophthalmic evaluation of the anterior and posterior segments, including visual field with Goldmann perimeter and fluorescein fundus angiography. All patients aged 50 years and older were also investigated for giant cell arteritis (GCA). Every attempt was made to rule out other causes of visual loss. Follow-up evaluation was similar to the initial evaluation except angiography. Aetiologically, PION can be divided into three types: arteritic due to GCA, nonarteritic not due to GCA, and surgical following a surgical procedure. Steroid therapy was given to only those nonarteritic PION patients who opted to try that, but was given to all arteritic PION patients. PION was nonarteritic in 28 patients (35 eyes), arteritic in 12 (14 eyes), and surgical in three (four eyes). Visual acuity varied between 20/20 and no light perception--it was count fingers or less in 19 of 35 eyes with nonarteritic PION, four of 14 in arteritic, and all four with surgical PION. The most common visual field defect was central visual loss, alone or in combination with other types of visual field defects. Initially, optic disc and fundus showed no abnormality but the disc usually developed pallor in about 6-8 weeks. Aggressive treatment with high-dose systemic steroid during the very early stages of nonarteritic PION produced significant improvement of visual acuity as well as visual fields, but not so in arteritic or surgical PION. However, some spontaneous visual improvement also occurred in some untreated nonarteritic PION cases. PION is a distinct clinical entity but should be diagnosed only after exclusion of all other causes of visual loss. In all patients older than 50, GCA must be ruled out. There is usually marked visual loss, with central field defect being the most common. The study suggests that high-dose steroid therapy in nonarteritic PION, soon after the onset of visual loss, resulted in significant visual improvement compared to the untreated cases, but not in arteritic and surgical PION.

Visual fields in retinoblastoma survivors.

To describe the visual field defects in retinoblastoma survivors and relate those defects to characteristics such as tumor size, tumor location, and treatment modality. Thirty-one patients treated for retinoblastoma were included in this study. Humphrey visual fields were determined in 33 eyes. Twenty-seven patients (29 eyes, 68 tumors) had sufficient diagnosis and treatment data available for further analysis. Twenty-six of the 27 patients had both absolute and relative visual field defects. Four types of visual field defects were observed and correlated with location of the tumor and therapy to the individual tumors: (1) no residual defect, (2) absolute scotoma, (3) arcuate and sector scotoma, and (4) "pseudo"-visual field defects caused by relative enophthalmos resulting from radiation. Patients with retinoblastoma demonstrate a variety of long-term visual field defects after treatment for their intraocular disease. Characteristics that determine the size and type of defects are tumor size, tumor location, and treatment method.

Craniopharyngioma: a review of long-term visual outcome.

To assess the clinical presentation and long-term visual outcome in a series of patients with craniopharyn-gioma. Retrospective case review. Thirty-six patients were reviewed, comprising 19 female patients and 17 male patients. The age range was 2-77 years with a bimodal distribution of 17 children (mean age 10 years) and 19 adults (mean age 47 years). Blurred vision was the most common visual complaint (23 cases, 64%) and headache the most frequent systemic complaint (19 cases, 53%). The average duration of systemic symptoms was 45 weeks compared to 10 weeks for visual symptoms. Deficits in visual acuity occurred in 13 patients (36%) and showed no significant change from initial presentation to final review. Sixteen patients (44%) had bitemporal hemianopia on presentation and pleomorphism (change from one type of visual field defect to another) occurred in 11 patients. Recurrence of tumour occurred in 15 patients (42%) and was more likely in children (59%) than adults (26%). The mean time period to recurrence was 7 years. The average follow-up period for all cases was 10 years. Patients with craniopharyngioma generally present late, and the visual symptoms are often preceded by a long history of systemic symptoms. Children are more likely to present with systemic symptoms than adults. Visual field pleomorphism is a feature of craniopharyngioma and occurred in one-third of the patients. Local recurrence is common. Although magnetic resonance imaging is the recommended means of follow up, regular neuro-ophthalmic review is useful in the early detection of anterior visual pathway compression by recurrent tumour.

Author’s reply

We appreciate Dr. Lee’s review of anatomic data regarding the optic chiasm. In particular, Dr. Lee provides a detailed summary of the functional anatomy of the chiasm in primates. Consequences on the visual field of compressions by tumors of the pituitary are not solely a function of the anatomy of the chiasm but also depend on other factors, such as variations in the position of the chiasm relative to the sella turcica. In antero-positioned chiasm, compression by the suprasellar extension of a pituitary adenoma will most likely affect the posterior part of the chiasm. Conversely, when the chiasm is retropositioned, consequences of suprasellar tumors will most likely affect the anterior part of the chiasm. Dynamics of tumor growth also play an important role in chiasmal lesions. In acromegaly, relatively rapid suprasellar extensions from the pituitary are often irregular, leading to visual field defects often less systematized than in other tumors. Moreover, local vascular factors may play a role in lesions of the chiasm. In our survey of 307 cases of acromegaly, we have observed 24 unilateral visual field defects. We are confident that Goldmann perimetry performed by trained technicians has enough sensitivity to detect defects of the macular bundle contralateral to a superotemporal defect. Although we have observed typical Traquair’s junctional scotoma in other causes of pituitary tumors, this type of visual field defect was not found in our series of patients with acromegaly.

Lebersche Optikusneuropathie mit klinischer Besserung

Spontaneous recovery in Leber's hereditary optic neuropathy is rare. Does the clinical course of Leber's hereditary optic neuropathy (LHON) differ between patients with and without spontaneous recovery? We compared the clinical and molecular genetic characteristics of 12 visually symptomatic patients having the classical clinical course of LHON who recovered spontaneously with those of 60 who did not. Classical fundus findings and typical visual field defects were comparable in the two groups; vision improved within 18 months in all cases. The worst visual acuity during the acute stage of LHON was 0.03 in the recovery group. Patients with the 3460 and especially the 14484 mutation had a better chance of recovery. No patient with the 11778 mutation who recovered had secondary mutations. Among patients who recovered women were underrepresented and heteroplasmy was more common. Some families showed a raised rate of clinically affected members with recovery. The clinical picture of LHON remains the same regardless of whether the patient recovers spontaneously. A higher rate of spontaneous recovery characterizes some families. Spontaneous recovery is rare in women. Heteroplasmy is frequent in patients with recovery. Our results show a better clinical course of LHON in patients with the 11778 mutation without secondary mutations. Prognosis is better if the peripapillary microangiopathy is seen for a relatively long period, and there is only partial optic atrophy.

Leber optic neuropathy in women and children

Leber's hereditary optic neuropathy is associated with point mutations in the mitochondrial DNA (mtDNA) that appear to be pathogenetic for this disease. These mutations affect nucleotide positions 3460, 11778 and 14484. Does the clinical course of LHON differ between men, women and children? We reviewed the clinical and molecular genetic characteristics of 15 visually symptomatic patients with the clinical diagnosis of LHON (11 women and 4 male children) and compared them with 66 men with LHON. LHON was confirmed clinically and with molecular genetic methods in all cases. Men, women and children showed no differences: Classic fundus findings and typical visual field defects were equally found in both sexes. However, age at the beginning of the disease, severity of LHON and rate of spontaneous recovery differed between groups. Women were older (19-55 years, average 31.3 years) than men (15-53 years, average 24.3 years) at the beginning of the disease. Women suffered more severely from LHON. Spontaneous recovery of vision in women was extremely rare. Many more women had a LHON-affected mother than men. All the affected children (9-14, average 11.7 years at the beginning of the disease) did not have a good visual outcome. There are some differences in the course of LHON between men and women, concerning age, severity of LHON and rate of spontaneous recovery. Children may also have an unfavorable prognosis.

Cerebral aneurysms causing visual symptoms: their features and surgical outcome

Cerebral aneurysms causing visual symptoms before surgery are relatively rare. We have experience with 17 cases of such aneurysms and report their clinical features and surgical outcome. The locations of aneurysms presenting with visual dysfunction in our series are as follows: internal carotid (IC)-cavernous aneurysms in six of 29 total cases, 21%; IC-ophthalmic aneurysms in nine of 36 total cases, 25%; and anterior communicating artery (A com A) aneurysms in two of 217 total cases, 1%. The size of the aneurysms, the period between the onset of symptoms and surgical treatment, the pre- and post-operative visual function, and the surgical methods used to treat the aneurysm were analyzed. All the visually symptomatic cases featured large (15–24 mm) or giant (>25 mm) aneurysms. Visual symptoms occurred before aneurysmal rupture in all cases but one. The type of visual field defect and the degree of reduced visual acuity were highly variable, without a typical clinical presentation. Five out of six IC-cavernous aneurysms were treated surgically with common carotid artery (CC) ligation or IC ligation with superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis. Three of these cases showed improvement of visual symptoms after surgery. Six out of nine IC-ophthalmic aneurysms were treated surgically (CC ligation or direct clipping), with four cases showing improvement of visual symptoms after surgery. One case of an A com A aneurysm featured a ruptured aneurysm that had physically penetrated the optic chiasm, while the other case was a giant unruptured aneurysm. The interval between the onset of symptoms and surgical treatment was the only factor identified which affected the clinical outcome of the aneurysms presenting with visual dysfunction. All cases that were determined to show improvement of visual function were treated surgically within 3 months of the onset of symptoms. Cerebral aneurysms presenting with visual dysfunction before surgery are most commonly large or giant, and unruptured. Recovery of visual function can most often be expected when surgical treatment is performed expeditiously, before the visual dysfunction becomes irreversible.

Short-wavelength automated perimetry and retinal nerve fiber layer evaluation in suspected cases of glaucoma.

To determine if short-wavelength automated perimetry (SWAP) provides evidence that indicates early functional losses in ocular hypertensive subjects and to establish a direct comparison with early structural abnormalities in the retinal nerve fiber layer (RNFL). A total of 160 eyes belonging to 83 patients with ocular hypertension (intraocular pressure >21 mm Hg and normal results on standard automated perimetry evaluation), on which a SWAP and RNFL study were performed, were examined. One hundred twenty-eight age-matched subjects without ocular hypertension were evaluated to establish the 95% and 99% confidence intervals at each of the 76 exploration points of the SWAP test. The RNFL study results were normal in 83 cases (51.8%) and pathologic in 77 cases (48.1%). The SWAP results were pathologic in 57 cases (35.6%). Significant differences (P<.001) were observed when comparing the distribution of normal and pathologic SWAP results among the types of defects in the RNFL (focal wedge, diffuse atrophy, and mixed atrophy). Short-wavelength automated perimetry is a useful test for the early detection of visual field losses. It is more sensitive than standard automated perimetry and provides a high association with RNFL assessment, which has proved capable of detecting signs of glaucomatous damage several years before the onset of the typical visual field defects.

A novel mutation in the GLC1A gene causes juvenile open-angle glaucoma in 4 families from the Italian region of Puglia.

Primary open-angle glaucoma encompasses a complex of potentially blinding ocular diseases characterized by a normal-appearing angle of the anterior chamber, a characteristic degeneration of the optic nerve with resultant typical visual field defects, and usually, an elevated intraocular pressure. It can be subdivided into 2 groups according to the age at onset: the more prevalent chronic open-angle glaucoma diagnosed after 40 years of age, and the less common juvenile form, which occurs between 3 years of age and early adulthood. A locus for primary open-angle glaucoma (GLC1A) has been mapped to a 3-centimorgan region of the long arm of chromosome 1 (1q23-25). Recently, the myocilin (MYOC) gene, located in this chromosomal interval, has been found mutated in several patients affected by primary open-angle glaucoma. To describe the clinical and molecular genetic features of 4 pedigrees affected by autosomal dominant juvenile open-angle glaucoma, all from the Italian region of Puglia. Clinical study, gonioscopy, automated perimetry, and DNA analysis were performed on several members of the 4 families. We identified a new molecular defect (1177GACA-->T) in the third exon of the GLC1A gene. This mutation is present in all affected persons and in 2 still phenotypically normal persons. Our results are important for diagnostic purposes because it is now possible to identify asymptomatic carriers, for whom clinical surveillance for the early detection and treatment of glaucoma may be suggested.

Visual fields in patients with posterior GPi pallidotomy.

The objective of this study was to describe the incidence and types of visual field defects after posterior globus pallidus internus (GPi) pallidotomy for Parkinson's disease. The creation of the pallidotomy lesion carries a risk of damaging neighboring structures such as the optic tract. The reported frequency of visual field defects in patients after pallidotomy varies from 0 to 40%. Goldmann visual field testing was performed on 40 patients who underwent microelectrode-guided posterior GPi pallidotomy. The optic tract was identified during the procedure by listening during microelectrode recording for the evoked responses to light flashes and by assessing stimulation-induced subjective responses. After the first 18 patients, lesioning thresholds were increased from 0.5 to > or =1.0 mA so that the lesion was placed more distant from the optic tract. The location of individual lesions was determined on postsurgical MRI. Three patients (7.5%) had visual field defects likely related to the pallidotomy. These were contralateral homonymous superior quadrantanopias, associated in two patients with small paracentral scotomas. The incidence of visual field defects with the early technique was 11% (2/18) and decreased to 4.5% (1/22) after thresholds for lesioning were increased. Except for the location of the lesion relative to the optic tract (more ventral, adjacent to or extending into the optic tract), no other variable correlated with a post-pallidotomy visual field defect. Microelectrode-guided GPi pallidotomy is a relatively safe procedure as regards visual function even when the optic tract is used as a guide for lesion placement.

Optic nerve head-related visual fields

A variety of pathological processes at the level of the optic nerve head, such as papilledema, circulatory diseases, glaucoma, as well as certain inborn abnormalities, cause visual-field defects. The type of visual-field defect is dependent on the anatomic distribution of the nerve fibers involved and on the disease causing the optic nerve head damage. Therefore, the location and cause of the lesion determine the shape, extension, and depth of the visual-field defect.

Visual and blood flow responses in low-tension glaucoma

Low or normal-tension glaucoma (NTG) is a rare clinical condition characterized by a glaucomatous cupping of the optic disk associated with the appearance of typical visual field defects, without ocular hypertension. According to several authors, NTG accounts for 5–15% of primary open angle glaucomas (POAG). In our open study we obtained a complete documentation of clinical and instrumental data — tonometric curve, computerized perimetry, pattern electroretinogram, pulsatile ocular blood flow (POBF) and retinography — on 10 consecutive patients (18 eyes) affected by NTG. We found that the NTG patients were similar to the controls as regards arterial systemic pressure and heart rate, but that POBF values were lower in the NTG patients.

A back propagation neural network for the classification of visual field data

The computer assisted moving eye campimeter (CAMEC) is a visual field analyser that uses a moving target to hold the patient's fixation while the stimuli are presented. A neural network has been used to classify visual field data in the CAMEC format. This has the potential to provide self-testing diagnostic visual field examinations without the presence of skilled clinical personnel. A three-layer back propagation network was designed, with 110 units in the input layer, each unit corresponding to a test point on the CAMEC grid, a hidden layer of 40 units and an output layer of 22 units, each one corresponding to a particular type of visual field defect. Four hundred and ninety simulated field plots were generated in the CAMEC format by experienced ophthalmologists. These data were split into a training sets of 440 plots and a test set of 50 plots. Training of the neural network was accomplished by cycling the training set up to 50,000 times through the network. The effect of changing the number of hidden units was investigated using the test set of field plots. Optimizing the network configuration results in a classification accuracy of 98.2% for the training set of data and 96% for the test set.

Homonymous Quadrantic Visual Field Defect Resulting from Vertebrobasilar Insufficiency: Report of a Case

A patient showing a congruous homonymous superior quadrantanopsia was found at autopsy to have infarction of the striate cortex. The lesion involved the inferior bank of the calcarine fissure almost entirely and approximately one fifth of the superior bank. Additionally, infarctions of the visual association cortex and the pontine tegmentum were found. No lesions in the corresponding temporal lobe were present. Two types of visual field defects have been described in association with occipital lobe lesions: a monocular temporal crescentic defect if the lesion is anterior and a congruous homonymous hemianopsia if it is posterior. This patient seems to represent a variant of the latter. The most prominent difference with respect to quadrantanopsias resulting from lesions of the optic radiation is the high degree of congruity, especially in the central portion of the field. Association with nonocclusive vascular events related to vertebrobasilar hypoperfusion rather than embolization is also more common.

An analysis of step-like field defects in Gilles de la Tourette syndrome

Step-like visual field defects have been found in 37 individuals exhibiting Gilles de la Tourette syndrome (TS). The authors present an analysis of these step-like field defects. There is a near equal distribution of nasal and temporal steps in this group of individuals. The majority (76%) of steps face upwards. These results are independent of age and sex. However, drugs used in management of TS have a quantitative effect on visual fields. Drug therapy reduces the number of steps detected and also reduces areas of sensitivity difference at the horizontal meridian. Analysis also suggests that plotting at least two isopters will result in detection of a step-like field defect in all individuals exhibiting TS and in 91% of the eyes of such individuals.It is difficult to determine the underlying pathophysiology for these types of visual field defects. It is suggested that dopamine, a neurotransmitter of the retina might be involved in some manner in the pathogenesis of the visual field defects.

Cartographic deformations in a parabolic visual field map.

Visual fields are traditionally represented in the polar azimuthal equidistant projection. In this map, field areas are increasingly exaggerated with increasing visual angle. To facilitate description of central field defects, enlargement of the central visual field by a parabolic, non-linear projection has been proposed. The cartographic deformations associated with this projection were studied by using mathematical isopter models. A change from equidistant to parabolic projection not only altered relative isopter sizes but also their shapes. Also, the normal nasal-temporal asymmetry was obscured. Thus, the parabolic projection may conceal some types of visual field defects, e.g. loss of the temporal cresent. Neither projection represented surface areas correctly. It is argued that the area-true Lambert's projection would be ideal for visual field representation.

The spectrum of the visual field defects in the tilted disc syndrome Clinical study and review

The tilted disc syndrome is a common ocular anomaly characterized by dysversion of the optic disc, congenital crescent, situs inversus of the retinal vessels, and ectasia and depigmentation of the fundus. The anomaly causes visual field defects that can mimic the defects produced by other neuro-ophthalmological diseases, particularly chiasmal lesions. This paper deals with the visual field defects of the tilted disc syndrome in an attempt to classify them and to find differential features as regards similar defects of other origin. Four types of visual field were charted in patients with tilted disc syndrome: normal field, altitudinal, quadrantanopia-like and hemianopia-like defects. These latter two defects tend to cross the vertical meridian, point towards the blind spot, and are partly surrounded by an arc of vision. A correspondence exists between the type of visual field defect and the position of the depigmented/ectatic area of the fundus.

Performance of computer assisted perimeters.

This article describes a large number of points that have to be considered when evaluating computer-assisted-perimeters (CAP). With the ever increasing numbers of commercially available CAP over a large quality-range the choice of a CAP for a certain type of practice becomes very difficult indeed. The authors starting position and present-day manual perimetry are first described. The shortcomings of kinetic perimetry are demonstrated. A differentiation of several types of visual field defects is given. Such a differentiation is indispensable for the evaluation of CAP. Each phase of the visual field examination: detection, limited-and extended assessment is considered. Special attention has been given to examination-strategies. They are the most important part of the software of CAP and usually the least comprehensible part. The existing threshold and suprathreshold-techniques are explained. The author expresses a preference for a threshold-related gradient-adapted suprathreshold detection strategy. Random presentation, stimulus-timing, zero-fear presentations and reliability measurements among many other points are mentioned. The possibilities for an extended assessment and especially the data-base for follow-up examinations are described. The extended (or intermediate) assessment should provide sufficient information on spatial and intensity distribution of the defects. The important matter of the graphical display of CAP-results is elucidated. Statistical considerations may be one of the most promising features of CAP. Repetition of measurements will be necessary for such statistical treatments. The accurate numerical description of defectvolume and its fluctuation, and subsequently the absence or presence of significant change are ultimate goals of statistical programmes. General data on the hardware and software of a particular CAP provide the basis for understanding the results of a clinical evaluation of this CAP. The ultimate answer concerning the usefulness of a CAP can only be given by this clinical evaluation. The criteria and problems of such evaluations are discussed and illustrated with an example. In the addendum a suggestion for a classification of glaucomatous visual field defects is presented. The list of references gives over 160 publications related to CAP.