PURPOSE. To compare the number of retinal ganglion cells (RGCs) topographically mapped with specific visual field threshold test data in the same eyes among glaucoma patients. METHODS. Seventeen eyes of 13 persons with well-documented glaucoma histories and Humphrey threshold visual field tests (San Leandro, CA) were obtained from eye banks. RGC number was estimated by histologic counts of retinal sections and by counts of remaining axons in the optic nerves. The locations of the retinal samples corresponded to specific test points in the visual field. The data for glaucoma patients were compared with 17 eyes of 17 persons who were group matched for age, had no ocular history, and had normal eyes by histologic examination. RESULTS. The mean RGC loss for the entire retina averaged 10.2%, indicating that many eyes had early glaucoma damage. RGC body loss averaged 35.7% in eyes with corrected pattern SD probability less than 0.5%. When upper to lower retina RGC counts were compared with their corresponding visual field data within each eye, a 5-dB loss in sensitivity was associated with 25% RGC loss. For individual points that were abnormal at a probability less than 0.5%, the mean RGC loss was 29%. In control eyes, the loss of RGCs with age was estimated as 7205 cells per year in persons between 55 and 95 years of age. In optic nerves from glaucoma subjects, smaller axons were significantly more likely to be present than larger axons (R 2 = 0.78, P < 0.001). CONCLUSIONS. At least 25% to 35% RGC loss is associated with statistical abnormalities in automated visual field testing. In addition, these data corroborate previous findings that RGCs with larger diameter axons preferentially die in glaucoma.

Number of ganglion cells in glaucoma eyes compared with threshold visual field tests in the same persons.

Neuronal death in glaucoma.

Our understanding of glaucoma has undergone dramatic changes in the past decade. The ferment has derived from new epidemiologic information, improved diagnostic methods, and developments in surgical and drug therapy. This review concentrates on primary open-angle glaucoma, the most prevalent form of the disorder in Western countries. Definition Primary open-angle glaucoma usually affects both eyes and combines a particular abnormal appearance of the optic disk (optic-nerve head) with a slowly progressive loss of visual sensitivity (Figure 1). The characteristic appearance of the glaucomatous optic disk is visible by ophthalmoscopy (Figure 2). The present standard for determining visual loss in glaucoma . . .

Open-Angle Glaucoma

Glaucoma is a term describing a group of ocular disorders with multi-factorial etiology united by a clinically characteristic intraocular pressure-associated optic neuropathy. It is not a single entity and is sometimes referred to in the plural as the glaucomas. All forms are potentially progressive and can lead to blindness. The diverse conditions that comprise glaucoma are united by a clinically characteristic optic neuropathy: glaucomatous optic neuropathy (GON). Evidence suggests that the primary site of neurological injury is at the optic nerve head. This fact enables the conditions to be grouped, irrespective of the causal mechanism(s). The term experimental glaucoma implies model resemblance to the human condition. We propose that 'experimental glaucoma' be restricted to animal models with demonstrable features of GON and/or evidence of a primary axonopathy at the optic nerve head. A fundamental inadequacy in this framework is any reference to the pathogenesis of GON, which remains unclear.

/pdf/definition-of-glaucoma-clinical-and-experimental-concepts-4yhluwq4k8.pdf

Definition of glaucoma: clinical and experimental concepts

PurposeThe aims of this study were (a) to explore patients self-reported visual disability resulting from glaucoma by means of a questionnaire developed for this purpose; (b) identify activities strongly associated with a measure of visual field loss, (c) to quantify different psychophysical aspects

Quality of life in glaucoma and its relationship with visual function.

• We designed and evaluated a new test for the detection of early glaucoma damage in 133 persons who were classified as normal, suspected of having glaucoma, or having glaucoma. The test stimulates the entire visual field with a flashing white light under dark-adapted conditions. It can be performed easily by a high proportion of subjects and is as reproducible as present psychophysical tests. Glaucomatous eyes were discriminated from normal with a diagnostic power of 0.91 as judged by receiver operating characteristic analysis, and specificity and sensitivity were 91% and 86%, respectively. Glaucoma suspects with an abnormal response to the whole-field scotopic test were more likely to have other signs indicating early optic nerve injury, including a greater proportion of borderline field defects, nerve fiber layer defects, or glaucomatous fellow eyes. Assessment of whole-field scotopic sensitivity may be useful in glaucoma screening.

https://jamanetwork.com/HttpHandlers/ArticlePdfHandler.ashx?journal=ophth&articleId=639610&pdfFileName=archopht_110_4_031.pdf

A whole-field scotopic retinal sensitivity test for the detection of early glaucoma damage.

Objective To demonstrate differences in foveal constrast sensitivity (CS) between glaucomatous and nonglaucomatous eyes using a simple, rapid computerized test. Methods This study included consecutive patients with glaucoma (35 eyes) and age-matched control participants (23 eyes) with visual acuity of 20/30 or better. Patients with any other ocular disease, including cataract, were excluded. All participants underwent a comprehensive ocular examination, perimetry, and CS. Contrast sensitivity was examined by means of 2 computerized psychophysical tests. The transient method included the presentation of a target in a temporal, 2-alternative, forced-choice procedure, and the static method involved 4 forced-choice procedures. The targets were Gabor patches with spatial frequencies of 1.5 to 9.0 cycles per degree. The tests were conducted under photopic and mesopic conditions. Results Significantly lower foveal CS was found in glaucomatous eyes under photopic and mesopic conditions for all spatial frequencies ( P P P Conclusions The results indicate that foveal CS is impaired in glaucoma despite good visual acuity, suggesting that central visual function damage occurs in glaucoma. The similarity between the 2 methods of testing implies that the static method, being the shorter and easier one, may be used in future research. Further research is necessary to establish a CS testing role in the screening and monitoring of glaucoma.

/pdf/reduced-mesopic-and-photopic-foveal-contrast-sensitivity-in-1uu3gq4oe6.pdf

Reduced mesopic and photopic foveal contrast sensitivity in glaucoma.

Artificially Produced Quadrantanopsia in Computed Visual Field Testing

PURPOSE Evaluation of data obtained during diurnal intraocular pressure (IOP) measurements by means of the Goldmann Applanation tonometer in sitting and lateral decubitus positions. PATIENTS AND METHODS Retrospective cohort study of 41 consecutive untreated subjects (82 eyes) with ocular hypertension or suspicious discs. The IOP was measured by Goldmann Applanation tonometer in sitting position at 9 AM, 12 AM, 3 PM, and 6 PM; and in right lateral decubitus position around 12:15 PM. RESULTS In the right eye (RE) mean peak IOP was 22.19±4.68 mm Hg. In the left eye (LE) peak mean IOP was 22.19±3.8 mm Hg. In 91.5% of the eyes, the IOP increased in the lateral decubitus position. The average change in the RE was an increment of 4.22±2.67 mm Hg (P<0.001) and in the LE an increment of 3.51±3.11 (P<0.001). This increment was significantly higher in the dependent eye (i.e., lower eye) (P=0.049). Sixty-seven percent of eyes had a positional elevation of IOP between 2 and 5 mm Hg and 23.2% of eyes had IOP elevation between 6 and 12 mm Hg. In the great majority of the eyes (80.5% RE and 78% LE) the lateral decubitus IOP was greater than maximal diurnal sitting IOP. CONCLUSIONS The IOP in the lateral decubitus position was significantly higher than the mean maximal diurnal sitting IOP. Over 20% of the patients had an IOP increase of ≥6 mm Hg when lying down. Timely identification of patients with excessive postural elevation of IOP could affect their management and prevent visual fields loss.

Intraocular pressure curves of untreated glaucoma suspects and glaucoma patients in sitting and lateral decubitus positions using the goldmann applanation tonometer.

We investigated whether cataract decreases whole-field scotopic sensitivity, a measurement used for the detection of early glaucoma damage. The study population consisted of 33 patients scheduled for cataract surgery. Patients were >/=50 years old and had no ocular disease except senile cataract. The whole-field scotopic sensitivity of one eye of each subject was measured 1 day before and 3 months after cataract surgery. That of six persons of similar age without cataract was also measured twice, 3 months apart. Cataract extraction was associated with significantly improved sensitivity (p = 0.005). With stratification by cataract type, only persons with nuclear sclerosis demonstrated a significantly improved sensitivity after cataract surgery (p = 0.03). The magnitude of sensitivity improvement after surgery did not differ significantly between patients with mild compared to moderate cataract. Multiple regression analysis revealed that age, preoperative intraocular pressure, change in visual acuity, cataract type, and cataract severity were not independently significant predictors of change in sensitivity after cataract surgery. We conclude that cataract may alter the whole-field scotopic sensitivity score and may need to be taken into account in its use for glaucoma screening.

Yoseph Glovinsky

Papers

A whole-field scotopic retinal sensitivity test for the detection of early glaucoma damage.

Reduced mesopic and photopic foveal contrast sensitivity in glaucoma.

Artificially Produced Quadrantanopsia in Computed Visual Field Testing

Intraocular pressure curves of untreated glaucoma suspects and glaucoma patients in sitting and lateral decubitus positions using the goldmann applanation tonometer.

Effect of cataract on a scotopic sensitivity screening test for glaucoma.