Advanced Visual Field Loss Research Articles

Long-term visual outcomes and ocular complications in children with Marner's hereditary cataracts operated in the period 1940-2021.

To investigate visual development and long-term complications after cataract surgery in childhood. This cross-sectional study included patients from a family with Marner's hereditary cataracts who had cataract surgery before 18 years of age. The study was conducted from 1 January 2022 until 31 December 2022. The patients contributed to their medical files and participated in an updated ophthalmologic examination. We included 52 patients (101 eyes, 34 females). The median age at cataract surgery was 7 years (IQR: 5-10) and the age at examination was 40 years (IQR: 21-54). Primary and secondary intraocular lens implantation had been performed in 47.5% (25 patients, 48 eyes) and 16.8% (10 patients, 17 eyes). Visual acuity was ≤0.3 logMAR in 77% (78 eyes), and <0.5 logMAR in 8% (8 eyes). Glaucoma was present in 17% (9 patients, 12 eyes), ocular hypertension in 6% (3 patients, 4 eyes), and 10% (5 patients, 5 eyes) had prior retinal detachment. Mild visual field loss (2 < mean defect (MD) ≤ 6 dB) was found in 62% (63 eyes) and moderate to advanced visual field loss (MD > 6 dB) in 24% (24 eyes). Thirty-five patients (67%) held a driver's licence, and three were not allowed to drive due to low visual function. All patients were employed. After cataract surgery in childhood, many patients achieve normal visual acuity, but mild visual field loss is common. Long-term follow-up is important due to the high risk of glaucoma.

Suprathreshold Approaches to Mapping the Visual Field in Advanced Glaucoma.

Measuring the spatial extent of defects may be advantageous in advanced glaucoma where conventional perimetric sensitivity measurements are unreliable. We test whether suprathreshold tests on a higher density grid can more efficiently map advanced visual field loss. Data from 97 patients with mean deviation < -10 dB were used in simulations comparing two suprathreshold procedures (on a high-density 1.5° grid) to interpolated Full Threshold 24-2. Spatial binary search (SpaBS) presented 20-dB stimuli at locations bisecting seen/unseen points until the seen status of all neighbors matched or until tested points were adjacent. The SupraThreshold Adaptive Mapping Procedure (STAMP) presented 20-dB stimuli where entropy was maximal and modified the status of all points after each presentation, stopping after a fixed number of presentations (estimated as 50%-100% of the presentation number of a current procedure). With typical response errors, SpaBS had worse mean accuracy and repeatability than Full Threshold (both P < 0.0001). Compared to Full Threshold, mean accuracy (Full Threshold: median, 91%; interquartile range [IQR], 87%-94%) was slightly better with STAMP for all stopping criteria, although this was not statistically significant until 100% of conventional test presentations were used. Mean repeatability for STAMP was similar for all stopping criteria (P ≥ 0.02) compared to Full Threshold (Full Threshold: median, 89%; IQR, 82%-93%). STAMP accurately and repeatably maps the spatial extent of advanced visual field defects in as few as 50% of conventional perimetric test presentations. Further work is needed to test STAMP in human observers and in progressive loss. New perimetric approaches may improve information available for advanced glaucoma management and may potentially be more acceptable to patients.

Choroidal detachment and hypotony following selective laser trabeculoplasty: a case report

BackgroundSelective laser trabeculoplasty (SLT) is relatively safe and effective in lowering intraocular pressure (IOP). However, although rare, complications can occur after SLT. This report describes a patient with choroidal detachment due to hypotony following SLT without anterior chamber (AC) inflammation.Case presentationA 67-year-old man was referred for elevated IOP in his left eye with advanced glaucomatous visual field loss. He had previously been diagnosed with idiopathic uveitic glaucoma in the left eye, for which he underwent laser iridotomy, trabeculectomy, and cataract surgery. At the first visit, the IOP of his left eye measured by Goldmann tonometry was 28 mmHg despite maximally tolerated medical treatment. SLT was performed in his left eye, resulting in an IOP of 7 mmHg 7 days later. At 3 weeks post-procedure, the patient experienced ocular pain and decreased visual acuity in his left eye. Slit-lamp examination revealed deep anterior chamber depth and no inflammation reaction, but the IOP in his left eye was 4 mmHg, and both fundus and B-scan ultrasonography showed serous choroidal detachment. All anti-glaucoma agents were stopped, and the patient was started on treatment with oral prednisolone and cyclopentolate eye drops. Three weeks later, choroidal detachment had resolved and the IOP in his left eye had stabilized at 8 mmHg. Follow-up 3 months later showed that the IOP in his left eye remained stable.ConclusionsChoroidal detachment-related hypotony is a rare complication of SLT. This possible complication following SLT should be informed to the patients and considered when performing the procedure.

Cessation of Recurrent Bilateral Optic Disc Haemorrhages after Successful Trabeculectomy: A Case Report

Purpose: To describe a patient with primary open-angle glaucoma in whom bilateral recurrent optic disc haemorrhages disappeared permanently after trabeculectomy. Methods: A 67-old male patient was diagnosed with primary open-angle glaucoma and was followed for 10 years including best corrected visual acuity, visual field examinations, slit lamp examinations, Goldmann applanation tonometry, fundoscopy and optic disc photographs. Results: Optic disc haemorrhages were detected in 8 out of 30 preoperative visits in the right eye and in 3 out of 19 visits in the left eye. Trabeculectomy with intraoperative application of mitomycin C was performed in both eyes due to the advanced visual field loss with an inadequate intraocular pressure control despite maximum-tolerated medical therapy and because of the recurrent optic disc haemorrhages. No further optic disc haemorrhages were observed in either eye after trabeculectomy. Conclusion: Our case report demonstrates that recurrent bilateral optic disc haemorrhages can cease permanently after successful trabeculectomy.

Optical Coherence Tomography Angiography of the Retinal Circulation Following Trabeculectomy for Glaucoma.

Despite successful trabeculectomy, eyes with similar levels of peripapillary and macular vessel densities but with worse preoperative visual field mean deviations may experience functional and vascular decline after surgery. To evaluate the retinal microcirculation change after trabeculectomy according to glaucoma severity using optical coherence tomography angiography (OCTA). We enrolled 59 eyes of primary open angle glaucoma patients who underwent trabeculectomy. The eyes were categorized into 3 groups by preoperative visual field (VF) mean deviation (MD), group 1: MD>-12.0dB, group 2: MD -12.0 to -20.0dB, and group 3: MD <-20.0dB. OCTA was performed preoperatively and 1 year after trabeculectomy. The differences in the radial peripapillary capillary vessel density (pVD) and macular VD between preoperative and postoperative assessment were analyzed and compared in each group. Factors associated with the VD change after trabeculecomy were determined using linear regression analysis. Mean postoperative IOP and IOP reduction did not differ among the 3 groups after trabeculectomy. Preoperative pVD (37.2 vs. 36.6%, P =1.00) and macular VD (39.0 vs. 38.4%, P =1.00) did not differ between groups 1 and 2. Group 1 and 3 showed no changes in VD parameters after trabeculectomy (all, P >0.05). However, group 2 showed statistically significant decreases in pVD (36.6 vs. 32.9%, P <0.001) and macular VD (38.4 vs. 36.0%, P =0.010) after trabeculectomy. The reduction of pVD was associated with a decrease of IOP (Coefficient (β); 0.14, P =0.032) and VF MD (β; 0.15, P =0.0116) in group 2, respectively. Following successful trabeculectomy surgery for uncontrolled glaucoma with similar IOP reduction, glaucoma eyes with advanced visual field loss showed reduced pVD and macular VD measured by OCT-A. These findings may be relevant to disease progression.

Minimum Rim Width and Lamina Cribrosa Depth in Non-Glaucomatous and Glaucomatous U.S. Veterans

Purpose: Assess the utility of the MRW and lamina cribrosa depth measurements for detecting differences between non-glaucomatous and glaucomatous U.S. Veterans. Compare inter-eye differences of individuals with glaucoma. Method: 38 subjects were recruited per group: Group 1 included one eye of non-glaucomatous participants, and Group 2 included each qualifying eye of participants with glaucoma. Analysis compared Group 1 with the more affected eye only of Group 2 participants, and separately between the more and less affected eyes of group 2 participants. MRW measurements were obtained with Heidelberg Eye Explorer© (HEYEX). Average lamina cribrosa depths were measured manually utilizing HEYEX. Results: 26 subjects from Group 1 and 33 subjects from Group 2 were included. A significantly thinner MRW was found in glaucomatous eyes vs. non-glaucomatous eyes (210 µm vs. 309 µm; P &lt; .001). The normative database in HEYEX had an 85% sensitivity and 92% specificity to detect glaucomatous nerves. Among the 27 participants in Group 2 who had both eyes tested, eyes with more advanced visual field loss showed significantly thinner global MRW compared to fellow eyes (203 µm vs. 224 µm P = .03). Lamina cribrosa depths were non-significantly deeper in glaucomatous vs. non-glaucomatous eyes (476 µm vs. 429 µm P = .17). Conclusions: The MRW parameter differentiates between glaucomatous and non-glaucomatous optic nerves. Lamina cribrosa depths were non-significantly deeper in glaucomatous vs. non-glaucomatous participants. Post-hoc inter-eye data analysis suggested that inter-eye differences in gMRW values of glaucomatous eyes reflect asymmetric damage as correlated with the visual field

Standard Reliability and Gaze Tracking Metrics in Glaucoma and Glaucoma Suspects

To compare standard reliability metrics and gaze tracking (GT) metrics on the Humphrey field analyzer (HFA). Retrospective cross-sectional study. The study was performed at the VA Medical Center, San Diego, and included 494 glaucoma and glaucoma suspect patients who had an HFA 24-2 SITA Fast visual field (VF) performed in both eyes. Standard reliability metrics (fixation loss [FL], false-positive [FP], and false-negative [FN]) were compared to GT metrics (deviations of 1°-2° [M1], deviations of 3°-5° [M3], deviations >6° [M6], and tracking failure frequency [TFF]). The main outcome measures were Spearman rank-based correlation coefficient and area under the receiver operating characteristic (AUROC) curves between standard and GT reliability metrics. The 95th percentile limits for GT metrics were 66.7% for M1, 67.5% for M3, 49.5% for M6, and 79.8% for TFF. There were statistically significant correlations between standard and GT reliability metrics using the 95th percentile as a binary cutoff for GT metrics. However, low Spearman correlation values and AUROC calculations suggest little clinical significance of the associations. FN increased as VF severity worsened (P < .001). M6 was lower in eyes with mild compared to moderate and advanced VF loss (P=.012). GT metrics do not have a clinically significant association with standard reliability metrics. Both FN and M6 are influenced by VF severity. Aggregate GT metrics do not aid in reliability assessment. These findings suggest that GT metrics may provide an alternative or complementary measure of VF reliability.

This issue of ACTA

This issue of ACTA

Effect of glaucoma on identification of bottle cap color in ophthalmic medications.

A prospective, nonrandomized, observational trial of 60 glaucoma patients to correlate visual acuity and visual field with ability to distinguish bottle cap color of commonly used ophthalmic medications was conducted. A total of 103 eyes from 60 patients (30 women) were evaluated. The mean logMAR acuity was 0.34±0.54 (approximately 20/45 Snellen acuity), average Humphrey Visual Field (HVF) mean deviation was -8.58±8.69 dB, mean Ishihara plates (out of 14) were 11.78±4.15, and bottle cap color score (out of 10) was 8.56±2.51. Multiple linear regression analysis revealed an independent correlation of visual acuity (P=0.0137) and Ishihara score (P<0.001) with cap color score, but no significant effect with visual field mean deviation (P>0.05). Glaucoma patients with poor visual acuity, but not necessarily advanced visual field loss, are likely to have difficultly identifying the color of their bottle caps. Physicians should be cognizant of this potential issue when reviewing medications with patients.

Cancer-associated retinopathy preceding the diagnosis of cancer

BackgroundThe early diagnosis of cancer is of crucial importance and a key prognostic factor. Cancer-associated retinopathy (CAR) can be symptomatic prior to other manifestations directly related to malignant tumors. The aim of this study was to show that, in selected cases, ophthalmic findings are consistent enough with the diagnosis of CAR to trigger investigations aimed at detecting a previously unknown malignancy.MethodsThis was a monocentric retrospective case series performed in a tertiary referral center. Patients with a diagnosis of CAR were included. Diagnosis was based on the clinical presentation, the visual field and electroretinogram alterations. The clinical presentation, visual field testing and electroretinographic results were analyzed as well as the malignancies identified following the diagnosis of CAR. Follow-up data was collected.ResultsFour patients (two men, two women, median age 65.5 years) were included. All patients presented with posterior segment inflammation at initial presentation as well as advanced visual field loss and an extinguished electroretinogram. The best corrected decimal visual acuity was 0.8 or better in both eyes of three patients and decreased to 0.3 OD and O.2 OS in one patient due to a bilateral macular edema. No patient had a previously known history of cancer. Once the diagnosis of CAR was made, investigations aimed at identifying a malignant tumors subsequently led to the diagnosis of two cases of small cell lung tumors, of one prostate carcinoma and of a uterine sarcoma. The treatment of CAR included plasmapheresis, systemic corticosteroids, azathioprine, cyclosporine and periocular or intraocular corticosteroid injections. In all cases the intraocular inflammation resolved, but pigment mottling, diffuse retinal atrophy, optic disc pallor and arterial narrowing were among manifestations observed during the follow-up of the patients.ConclusionIn selected patients, findings suggestive of CAR can be useful for the early detection of a cancer.

Prophylactic anterior vitrectomy during cataract surgery in eyes at increased risk for aqueous misdirection

PurposePatients with chronic narrow angle glaucoma (CNAG) are at increased risk of developing aqueous misdirection (AM) following intraocular surgery. We present a retrospective case series on the use of posterior capsulorrhexis with core vitrectomy by an anterior approach (CAV) at the time of cataract extraction with or without glaucoma surgery as a prophylactic measure for the prevention of AM in CNAG. MethodsRetrospective case series of six phakic eyes in four patients with CNAG and other risk factors for AM who underwent posterior capsulorrhexis and CAV at the time of cataract surgery with or without glaucoma surgery. The main outcome measures were best-corrected visual acuity (BCVA), intraocular pressure (IOP), and post-operative complications. ResultsSix eyes in four subjects underwent posterior capsulorrhexis with CAV at the time of cataract surgery. The case was combined with incisional glaucoma surgery in the five eyes with advanced visual field loss. The mean logMAR BCVA and IOP improved from 0.554 ± 0.398 and 25.2 ± 13 mmHg, respectively, at the pre-operative visit to 0.257 ± 0.218 and 12.2 ± 1.7 mmHg, respectively, at final follow-up. Both eyes with nanophthalmos developed non-appositional serous choroidals that resolved with atropine, but the left eye required additional treatment with synechiolysis, intraocular lens repositioning, limited AV and endocyclophotocoagulation. There were no permanent, vision-threatening complications. Conclusions and importanceCAV can be safely combined with cataract surgery and glaucoma surgery, and it may be an effective intervention in eyes with CNAG and other risk factors for AM as a prophylactic measure against the development of AM.

Advanced pigment dispersion glaucoma secondary to phakic intraocular collamer lens implant

PurposeWe report a case of pigment dispersion glaucoma secondary to uncomplicated phakic intraocular collamer lens (ICL) (Visian ICL™, Staar Inc., Monrovia, CA) implant that resulted in advanced visual field loss. ObservationsA 50-year-old man presented for routine follow-up status post bilateral phakic intraocular collamer lens (ICL) placement 8 years earlier. He was incidentally found to have a decline in visual acuity from an anterior subcapsular cataract and elevated intraocular pressure (IOP) in the left eye. There were signs of pigment dispersion and no evidence of angle closure. Diffuse optic nerve thinning was consistent with advanced glaucomatous visual field defects. Pigment dispersion was also present in the patient's right eye, but without elevated IOP or visual field defects. The patient was treated with topical glaucoma medications and the phakic ICL in the left eye was removed concurrently with cataract surgery to prevent further visual field loss. Conclusions and importancePigment dispersion glaucoma is a serious adverse outcome after phakic ICL implantation and regular post-operative monitoring may prevent advanced visual field loss.

Systemic medication usage in glaucoma patients

To study the prevalence of the systemic use of some common classes of medications by glaucoma patients and their relationship to the prevalence and severity of chronic open-angle glaucoma (COAG) and primary-angle closure glaucoma (PACG). Observational prospective single-centre cross-sectional study. Glaucoma patients or their pharmacist provided an updated list of all systemic medications that they presently use. The relationship between glaucoma type and severity and medication use for diseases other than glaucoma was assessed by univariate statistics. We studied 514 glaucoma patients. They use a mean of 4.9 oral medications prescribed by a mean of 2.1 doctors. Antihypertensives, medications with anticholinergic properties, steroids, anticoagulants, and thyroid hormones were the most frequently prescribed groups of medications, used by 251 (49%), 178 (35%), 100 (19%), 218 (42%), and 108 (21%) patients, respectively. Steroid usage was associated with advanced visual field loss in COAG patients. Antihypertensives and medications with anticholinergic properties were not associated with severity of COAG and PACG, respectively, and these 3 groups were not associated with an increased prevalence of diagnosis of COAG or PACG. Glaucoma patients take many systemic medications in addition to their topical glaucoma treatment.

Performance of an iPad Application to Detect Moderate and Advanced Visual Field Loss in Nepal

To evaluate the accuracy and efficiency of Visual Fields Easy (VFE), a free iPad app, for performing suprathreshold perimetric screening. Prospective, cross-sectional validation study. We performed screening visual fields using a calibrated iPad 2 with the VFE application on 206 subjects (411 eyes): 210 normal (NL), 183 glaucoma (GL), and 18 diabetic retinopathy (DR) at Tilganga Institute of Ophthalmology, Kathmandu, Nepal. We correlated the results with a Humphrey Field Analyzer using 24-2 SITA Standard tests on 373 of these eyes (198 NL, 160 GL, 15 DR). The number of missed locations on the VFE correlated with mean deviation (MD, r=0.79), pattern standard deviation (PSD, r=0.60), and number of locations that were worse than the 95% confidence limits for total deviation (r= 0.51) and pattern deviation (r= 0.68) using SITA Standard. iPad suprathreshold perimetry was able to detect most visual field deficits with moderate (MD of-6 to-12 dB) and advanced (MD worse than-12 dB) loss, but had greater difficulty in detecting early (MD better than-6 dB) loss, primarily owing to an elevated false-positive response rate. The average time to perform the Visual Fields Easy test was 3minutes, 18 seconds (standard deviation=16.88 seconds). The Visual Fields Easy test procedure is a portable, fast, effective procedure for detecting moderate and advanced visual field loss. Improvements are currently underway to monitor eye and head tracking during testing, reduce testing time, improve performance, and eliminate the need to touch the video screen surface.

Strabismus and binocular diplopia due to advanced glaucomatous visual field loss

To describe a small series of patients with glaucoma whose strabismus and binocular diplopia were due to advanced visual field loss and inability to maintain sensory and motor fusion. This study is an observational case series of 3 patients with binocular diplopia, associated with variable strabismus, which was due to advanced visual field loss. Specific characteristics of the strabismus associated with advanced glaucomatous visual field loss were a subjective floating second image and marked variability of the prism and alternate cover measurements. Measured hypertropia changed in magnitude over a few seconds or a few minutes (even in 1 patient to a hypotropia), which distinguishes this specific type of strabismus from other types of comitant or incomitant strabismus associated with glaucoma. Although visual acuity was 20/400 or better in both eyes in all patients, there was advanced visual field loss in at least one eye. All patients responded poorly to prism, but their symptoms improved with a Bangerter filter applied to the spectacle lens or a MIN occlusion lens to further blur the worse-seeing eye. Variable strabismus associated with advanced glaucomatous visual field loss appears to be a distinct clinical entity that should be distinguished from other types of strabismus associated with glaucoma. Management of this specific type of strabismus is limited by inadequate visual field to fuse, analogous to hemifield slide, and therefore prism and/or strabismus surgery is unlikely to be successful. Primary treatment options include optical blur with Bangerter filters or a MIN occlusion lens although some patients prefer to ignore the second image.

Cases of advanced visual field loss at referral to glaucoma clinics - more men than women?

In many medical conditions 'late presentation' of disease is more of a problem for men than women. Risk of sight loss from glaucoma is certainly greater in those detected with advanced disease. We performed a retrospective study to test the hypothesis that men are more likely than women to have advanced visual field loss at referral to glaucoma clinics. We used 152 918 Humphrey visual fields from 32 147 patients from three regionally different hospitals in England; no other clinical data were made available apart from patient's age, sex and examination dates. The study population was defined as patients with measureable visual field loss in at least one eye at referral to glaucoma clinics. Cases of advanced visual field loss as defined by the Enhanced Glaucoma Severity Staging method at the first visit to secondary care were used as a proxy measure for late presentation of glaucoma. Age-adjusted relative risk (RR) was calculated as the ratio of the proportion of men to women with this proxy measure. Median (interquartile range) age and MD (worse eye) for 3733 men and 4264 women was 72 (63, 79) and 74 (64, 81) years and -6.4 (-11.7, -3.8) and -6.3 (-11.0, -3.8) dB respectively. Overall proportion of patients with advanced visual field loss at referral to glaucoma clinics was slightly higher in men (25.0%) than in women (22.3%); this difference was statistically significant (p < 0.01). Overall age-standardised RR was statistically significant (1.16; p < 0.001); a person with late presentation of glaucoma is 16% (95% confidence interval: 7-25%) more likely to be a man than a woman. A large number of patients with glaucomatous visual field defects are estimated to have advanced loss in at least one eye on referral to secondary care in England; risk for men more likely presenting with late disease is slightly greater than for women.

Lateral Inhibition in the Human Visual System in Patients with Glaucoma and Healthy Subjects: A Case-Control Study.

In glaucoma, the density of retinal ganglion cells is reduced. It is largely unknown how this influences retinal information processing. An increase in spatial summation and a decrease in contrast gain control and contrast adaptation have been reported. A decrease in lateral inhibition might also arise. This could result in a larger than expected response to some stimuli, which could mask ganglion cell loss on functional testing (structure-function discrepancy). The aim of this study was to compare lateral inhibition between glaucoma patients and healthy subjects; we used a case-control design. Cases (n = 18) were selected to have advanced visual field loss in combination with a normal visual acuity. Controls (n = 50) were not allowed to have symptoms or signs of any eye disease. Lateral inhibition was measured psychophysically on a computer screen, with (1) a modified illusory movement experiment and (2) a contrast sensitivity (CS) test. Illusory movement was quantified by nulling it with a real movement; measure of lateral inhibition was the amount of illusory movement. CS was measured at 1 and 4 cycles per degree (cpd); measure of lateral inhibition was the difference between log CS at 4 and 1 cpd. Both measures were compared between cases and controls; analyses were adjusted for age and gender. There was no difference between cases and controls for these two measures of lateral inhibition (p = 0.58 for illusory movement; p = 0.20 for CS). The movement threshold was higher in cases than in controls (p = 0.008) and log CS was lower, at both 1 (-0.20; p = 0.008) and 4 (-0.28; p = 0.001) cpd. Our results indicate that spatially antagonistic mechanisms are not specifically affected in glaucoma, at least not in the intact center of a severely damaged visual field. This suggests that the structure-function discrepancy in glaucoma is not related to a decrease in lateral inhibition.

Progression to Legal Blindness in Patients With Normal Tension Glaucoma: Hospital-Based Study.

To determine the probability of an eye with normal tension glaucoma (NTG) progressing to legal blindness under standard ophthalmic care. Patients diagnosed with NTG (n = 382) between 1985 and 2007 at Gifu University Hospital were followed for at least 5 years under standard ophthalmic care. The collected data included the best-corrected visual acuity (BCVA), intraocular pressure (IOP), and visual field status. Blindness was defined as a BCVA of <20/400 or a constriction of the central visual field to <10° according to the World Health Organization criteria. Kaplan-Meier life table analysis was used to estimate the probability of progressing to blindness in one or both eyes. The mean follow-up period after diagnosis was 13.3 ± 5.4 years with a range of 5.0 to 29.1 years. At diagnosis, 18 patients (4.7%) had unilateral blindness due to glaucoma. At final examination, 34 patients had progressed to unilateral blindness and 5 to bilateral blindness. The Kaplan-Meier life table analysis estimate for unilateral blindness was 5.8 ± 1.3% at 10 years and 9.9 ± 1.9% at 20 years. Similarly, that for bilateral blindness was 0.3 ± 0.3% at 10 years and 1.4 ± 0.8% at 20 years. A Cox proportional hazard model analysis showed that a lower initial BCVA (P < 0.001), a worse initial AGIS (Advanced Glaucoma Intervention Study) score (P = 0.002), and the frequency of changing glaucoma medications during the follow-up periods (P < 0.001) were significantly correlated with the development of blindness in at least one eye. The probability of blindness in eyes with NTG is much lower than previously reported in patients with high-tension glaucoma. Nevertheless, special care should be taken to follow NTG patients, and especially those with worse BCVA and more advanced visual field loss at diagnosis.

Lateral inhibition in the human visual system in healthy subjects and in patients with glaucoma

AbstractPurpose In glaucoma, the density of retinal ganglion cells (RGCs) is reduced. It is largely unknown whether and how this influences the spatial interactions between the remaining RGCs. A decrease in lateral inhibition might arise and could result in a larger than expected response to some stimuli, which could mask RGC loss on functional glaucoma testing. The aim of this study was to compare lateral inhibition in the visual system between glaucoma patients and healthy subjects.Methods A case‐control study was performed with 14 glaucoma patients and 50 healthy subjects. Cases were selected to have advanced visual field loss in combination with a normal visual acuity. Controls had to have a negative ophthalmic and family history, normal eye pressure, and a normal acuity. Experiments were performed monocularly. Lateral inhibition was measured psychophysically on a computer screen, with (1) a modified illusory movement experiment and (2) a contrast sensitivity (CS) test. The illusory movement was quantified by nulling it with a real movement; measure of lateral inhibition was the amount of illusory movement. Log CS was measured at 1 and 4 cpd; measure of lateral inhibition was the difference between log CS at 1 and 4 cpd. Both measures of lateral inhibition were compared between cases and controls; analyses were adjusted for age with multiple linear regressionResults There was no difference in lateral inhibition between cases and controls (P=0.76 for illusory movement; P=0.84 for CS testing). Log CS was lower in the cases than in the controls at both 1 (‐0.21; P=0.006) and 4 (‐0.22; P=0.016) cpd.Conclusion Lateral inhibition is not decreased in glaucoma patients, at least not in patients with a normal visual acuity.

Eye movements and reading in glaucoma: observations on patients with advanced visual field loss.

To investigate the relationship between reading speed and eye movements in patients with advanced glaucomatous visual field (VF) defects and age-similar visually healthy people. Eighteen patients with advanced bilateral VF defects (mean age: 71, standard deviation [SD]: 7 years) and 39 controls (mean age: 67, SD: 8 years) had reading speed measured using short passages of text on a computer set-up incorporating eye tracking. Scanpaths were plotted and analysed from these experiments to derive measures of 'perceptual span' (total number of letters read per number of saccades) and 'text saturation' (the distance between the first and last fixation on lines of text). Another eye movement measure, termed 'saccadic frequency' (total number of saccades made to read a single word), was derived from a separate lexical decision task, where words were presented in isolation. Significant linear association was demonstrated between perceptual span and reading speed in patients (R (2) = 0.42) and controls (R (2) = 0.56). Linear association between saccadic frequency during the LDT and reading speed was also found in patients (R (2) = 0.42), but not in controls (R (2) = 0.02). Patients also exhibited greater average text saturation than controls (P = 0.004). Some, but not all, patients with advanced VF defects read slower than controls using short text passages. Differences in eye movement behaviour may partly account for this variability in patients. These patients were shown to saturate lines of text more during reading, which may explain previously-reported difficulties with sustained reading.