Tuberculum meningioma with recovery of glaucoma-like visual field defects after chiasmal decompression: a case report.

BACKGROUND: To report a case of tuberculum meningioma with recovery of glaucoma-like visual field defects after chiasmal decompression. CASE PRESENTATION: A 39-year-old woman presenting with headache was found to have bilateral arcuate retinal nerve fiber layer (RNFL) thinning on optical coherence tomography (OCT) with a corresponding arcuate scotomas consistent with glaucomatous change. However a suprasellar tumor compressing the anterior chiasm from below was found on magnetic resonance imaging of the brain. After resection of the mass, which was diagnosed as meningothelial meningioma by the pathological examination, the glaucoma-like visual field defects resolved despite the RNFL thinning on the OCT showing no improvement. CONCLUSIONS: Chiasmal compression may mimic glaucoma and produce arcuate scotoma rather than temporal visual field loss. There is a possibility that the development of chiasmal compression somehow converted preperimetric glaucoma into a more advanced form accompanied by visual field defects and that the glaucoma reverted to the preperimetric state after chiasmal decompression.

Optical coherence tomography detects early optic nerve damage before visual field defect in patients with pituitary tumors.

Optical coherence tomography (OCT) is a useful tool for predicting visual recovery after the removal of pituitary tumors. However, the utility of OCT in patients with pituitary tumors and a normal visual field is unclear. We aimed to analyze OCT features in pituitary tumors without visual field defects. Pituitary tumors without visual field defects were selected. A total of 138 eyes from 69 patients, assessed by the Humphrey visual field test and OCT, were enrolled in this study. Using preoperative coronal sections of MR images, patients were divided into chiasmal compression (CC) and non-chiasmal compression (non-CC) groups, and OCT characteristics were examined. The CC and non-CC groups consisted of 40 and 29 patients, respectively. There were no differences in age, sex, tumor type, or degree of visual field testing, but the tumor size was different between the two groups. On OCT, macular thickness ganglion cell complex (mGCC) was significantly thinner in the CC group than that in the non-CC group (112.5 vs 117.4 um, P < 0.05). Based on a database of healthy participants, 24% and 2% of eyes in the CC and non-CC groups had abnormal mGCC thickness (P < 0.01), respectively. In a sub-analysis of the CC group, patients with an abnormal mGCC thickness were older than a normal one (58.2 vs 41.1 years, p < 0.01). OCT can detect early optic nerve damage due to optic CC by pituitary tumors, even in normal visual fields. The degree of mGCC thinning may provide an appropriate surgical timing for pituitary tumors that compress the optic chiasm.

Transient Visual Obscurations Without Papilloedema as the Heralding Symptom of Chiasmal Compression.

Transient visual obscurations (TVOs) represent brief ischaemic events of the optic nerve. These most commonly occur in the setting of raised intracranial pressure or more localised aetiologies within the orbit that result in decreased perfusion pressure. Transient vision loss has rarely been associated with pituitary tumours or optic chiasm compression, but details are lacking. We describe classic TVOs that completely resolved following resection of a pituitary macroadenoma causing chiasmal compression with a relatively normal eye examination. Clinicians should consider neuro-imaging in patients with TVOs and a normal evaluation.

Optical coherence tomography retinal ganglion cell complex analysis for the detection of early chiasmal compression.

PURPOSE: To report patients with sellar tumors and chiasmal compression with normal visual fields, who demonstrate damage to the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) on optical coherence tomography (OCT). METHODS: Seven patients with sellar tumors causing mass effect on the optic chiasm without definite visual field defect, but abnormal GCC are described. GCC/RNFL analyses using Cirrus-OCT were classified into centiles based on the manufacturer's reference range. RESULTS: In seven patients with radiologic compression of the chiasm by a sellar tumor, OCT-GCC thickness detected compressive chiasmopathy before visual defects became apparent on standard automated visual field testing. Without OCT, our patients would have been labelled as having normal visual function and no evidence of compressive chiasmopathy. With only OCT-RNFL analysis, 3/7 patients would still have been labelled as having no compression of the anterior visual pathways. CONCLUSIONS: These patients show that OCT-GCC analysis is more sensitive than visual field testing with standard automated perimetry in the detection of compressive chiasmopathy or optic neuropathy. These cases and previous studies suggest that OCT-GCC analysis may be used in addition to visual field testing to evaluate patients with lesions compressing the chiasm.

Programme choice for perimetry in neurological conditions (PoPiN): a systematic review of perimetry options and patterns of visual field loss.

BACKGROUND: Visual field loss occurs frequently in neurological conditions and perimetry is commonly requested for patients with suspected or known conditions. There are currently no guidelines for how visual fields in neurological conditions should be assessed. There is a wide range of visual field programs available and the wrong choice of program can potentially fail to detect visual field loss. We report the results of a systematic review of the existing evidence base for the patterns of visual field loss in four common neurological conditions and the perimetry programs used, to aid the design of future research and clinical practice guidelines. METHODS: A systematic search of the literature was performed. The inclusion criteria required studies testing and/or reporting visual field loss in one or more of the target conditions; idiopathic intracranial hypertension, optic neuropathy, chiasmal compression and stroke. Scholarly online databases and registers were searched. In addition articles were hand searched. MESH terms and alternatives in relation to the four target conditions and visual fields were used. Study selection was performed by two authors independently. Data was extracted by one author and verified by a second. RESULTS: This review included 330 studies; 51 in relation to idiopathic intracranial hypertension, 144 in relation to optic neuropathy, 105 in relation to chiasmal compression, 21 in relation to stroke and 10 in relation to a mixed neuro-ophthalmology population. CONCLUSIONS: Both the 30-2 and 24-2 program using the Humphrey perimeter were most commonly reported followed by manual kinetic perimetry using the Goldmann perimeter across all four conditions included in this review. A wide variety of other perimeters and programs were reported. The patterns of visual field defects differ much more greatly across the four conditions. Central perimetry is used extensively in neurological conditions but with little supporting evidence for its diagnostic accuracy in these, especially considering the peripheral visual field may be affected first whilst the central visual field may not be impacted until later in the progression. Further research is required to reach a consensus on how best to standardise perimetry for neurological conditions.

Evaluation of pattern ERG as a visual prognosticator in chiasmatic tumours.

BACKGROUND: Tumours compressing the optic pathway may lead to irreversible loss of vision that can be detected by pattern electroretinogram owing to its relation to ganglion cell function. This study aims to assess whether pattern electroretinogram is a useful tool to predict visual outcome following decompressive surgery for sellar and parasellar tumours. DESIGN: Prospective, non-randomized study. PARTICIPANTS: Forty eyes of 20 patients with radiologically confirmed tumours in and around the sellar region. METHODS: Patients were followed for 6 weeks following surgical intervention (transphenoidal or transfrontal approach). MAIN OUTCOME MEASURES: Best-corrected visual acuity, visual fields (Humphrey 30-2 standard automated perimetry) and pattern electroretinogram. The ratio N95/P50 (N2/P1) was calculated for each recording. RESULTS: There was improvement in visual fields in 35.4% eyes with normal n2/p1 ratio (>1.1) as compared to 22.2% with abnormal ratio. Also, 9.6% eyes with normal ratio and 11.1% with an abnormal ratio deteriorated postoperatively. No association was found between pattern electroretinogram and visual fields preoperatively and postoperatively (P = 0.093). CONCLUSIONS: Pattern electroretinogram may not be a useful prognostic indicator in the preoperative assessment of tumours causing chiasmal compression. An abnormal N2/P1 ratio is not necessarily associated with lesser or no clinical improvement following surgery as compared to an eye with a normal pattern electroretinogram.

Predicting visual outcomes after decompression of pituitary tumours based on stratified inner-retinal layer thickness and age.

PURPOSE: The purpose of the study was to evaluate the potential role of stratified preoperative optical coherence tomography (OCT) measurements and age in predicting postoperative visual field (VF) improvement among adult patients with chiasmal compression due to pituitary tumours after decompression surgery. METHODS: Postoperative visual outcomes were analysed using mean deviation of the VF test. Eyes were divided into three groups based on preoperative OCT parameters including peripapillary retinal nerve fibre layer (pRNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness: groups 1, 2 and 3 with pRNFL thickness <65 µm, 65 µm or more but <85 µm, and 85 µm or more, respectively. The GCIPL thickness was also divided into three groups based on values ranging from 55 to 77 µm. Each group was further categorized according to age: 20 years or older but younger than 40 years, 40 years or older but younger than 60, and 60 years or older. RESULTS: This study included 197 eyes of 197 patients with chiasmal compression due to pituitary tumours. No patient showed complete VF recovery in group 1 with a preoperative pRNFL thickness <65 µm or a GCIPL thickness <55 µm regardless of age. These groups showed the worst VF outcome (pRNFL, p = 0.0001; GCIPL, p < 0.0001). However, a significant recovery in VF (greater than 2 dB) was observed in 45% of group 1 patients based on pRNFL thickness and in 61.54% of group 1 patients according to GCIPL thickness. In groups 2 and 3 with a preoperative pRNFL thickness of 65 µm or more and a GCIPL thickness of 55 µm or more, the rate of complete VF recovery decreased as subjects' ages increased. Group 3 with a preoperative pRNFL thickness of 85 µm or more and a GCIPL thickness of 77 µm or more were 2.5-fold and 4.0-fold more likely to completely recover VF, respectively, compared with group 2. CONCLUSIONS: Stratified preoperative pRNFL and GCIPL thicknesses measured via OCT in different age categories are effective biomarkers for predicting visual functional outcomes.

Microvascular Changes in Pituitary Adenoma Correlate with Structural Measurements and Visual Field Loss.

Purpose: This study aimed to determine the relationship among microvascular changes, retinal nerve fiber layer (RNFL) thickness, and visual field loss in pituitary adenoma (PA) patients. Patients and Methods: Optic disc and macular vessel densities were measured, using optical coherence tomography angiography (OCTA) in the eyes from PA patients with radiographic chiasmal compression. Comparisons of retinal microvascular and structural parameters were conducted between PA patients and age/sex-matched healthy controls. The PA group was subdivided into PA with temporal visual field defects (perimetric PA) and PA without visual field defect (preperimetric PA) groups. The study determined correlation between microvascular parameters and optic nerve damage, including visual field and structural measurements. Subgroup analyses were performed to distinguish the different microcirculation characteristics of the perimetric PA eyes and preperimetric PA eyes. Results: Forty-five eyes from 40 PA patients and 24 eyes from 24 healthy controls were recruited prospectively. Eyes in the perimetric PA group had significantly decreased optic disc vessel density but slightly increased macular vessel density at superficial retinal capillary plexus (SCP) level. Eyes in the preperimetric PA group had significantly increased macular vessel density at SCP level. Optic disc vessel density was inversely correlated with visual field mean deviation and positively correlated with RNFL thickness. Conclusion: Significantly decreased optic disc vessel density in the perimetric stage but increased SCP macular vessel density in the preperimetric stage were found in PA patients. Our data suggest that increased SCP macular vessel density may serve as an early biomarker of preperimetric PA eyes, while decreased optic disc vessel density could be a late biomarker of perimetric PA eyes. Optic disc vessel density was correlated with RNFL thickness and visual field loss in PA eyes. OCTA is a useful tool to detect retinal microvascular changes and access the severity of neural impairments in chiasmal compression caused by PA.

SD-OCT parameters and visual field defect in chiasmal compression and the diagnostic value of neural network model.

PURPOSE: To evaluate the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) measurements using spectral domain optical coherence tomography (SD-OCT) in patients with chiasmal compression and analyze the diagnostic value of a neural network model. METHODS: Forty-seven patients with chiasmal compressive disorder were recruited and divided into two groups depending on the visual field defect (perimetric; group 1 and preperimetric; group 2). Fifty-seven normal subjects were also recruited (group 3). Peripapillary RNFL and macular GCIPL were analyzed in each group. A multilayer perceptron was trained using a training dataset and derived a neural network model. The diagnostic performances were compared using the area under the receiver operating curve (AUROC) between each parameters and neural network model. RESULTS: All macular GCIPL parameters, except inferotemporal GCIPL thickness, were thinner in group 1 than in group 2 and group 3, with barely any difference between group 2 and group 3 parameter values. The diagnostic power of the neural network model, minimum GCIPL, and inferonasal GCIPL were superior when compared with other parameters; the diagnostic values of these three parameters are not significantly different in discriminating the patients and normal control. However, the neural network exhibited the best diagnostic power in distinguishing group 2 and group 3. CONCLUSION: Macular GCIPL was reduced in chiasmal compression patients with visual field defect which was not evident in the preperimetric state. Neural network model showed superior diagnostic value in discriminating the preperimetric patients from normal control. The results suggest that neural networks may be helpful in the early diagnosis of chiasmal compression.

Segmented retinal analysis in pituitary adenoma with chiasmal compression: A prospective comparative study.

PURPOSE: The aim of this study was to determine the alteration in ganglion cell complex and its relationship with retinal nerve fiber layer (RNFL) thickness as measured by spectral-domain optical coherence tomography (OCT) in pituitary adenoma cases and also its correlation with visual field (VF). METHODS: This is a prospective comparative study wherein detailed neuro-ophthalmic examination including perimetry, RNFL and ganglion cell layer inner plexiform layer (GCL-IPL) thickness were measured preoperatively in the cases of pituitary adenoma with chiasmal compression with visual symptoms and field changes who were planned for neuro-surgical intervention. These parameters were repeated 1 year after the surgery. GCL-IPL, RNFL parameters were compared with controls and were correlated with VF mean deviation (MD). The diagnostic power of GCL-IPL was tested using the receiver operating characteristic (ROC) curve. Healthy age and sex-matched controls without any ocular and systemic abnormality were taken for comparison. RESULTS: Twenty-four patients qualified the inclusion criteria. A significant thinning of GCL-IPL (P = 0.002) and RNFL (P = 0.039) was noticed in the pituitary adenoma group. GCL-IPL (r = 0.780 P < 0.001) and RNFL (r = 0.669, P < 0.001) were significantly correlated with the MD. The ROC curve values of GCL-IPL were 0.859 (95% confidence interval 0.744% to 0.973) and of RNFL were 0.731 (95% confidence interval 0.585-0.877). The diagnostic ability of GCL-IPL was more as compared to the RNFL analysis, although it was statistically insignificant (P = 0.122). CONCLUSION: GCL-IPL measurements on the OCT are a sensitive tool to detect early anterior visual pathway changes in chiasmal compression for pituitary adenoma patients.

Long term predictive ability of preoperative retinal nerve fiber layer thickness in visual prognosis after chiasmal decompression surgery.

OBJECTIVE: To investigate the relationship between preoperative retinal nerve fiber layer (RNFL) thickness and the recovery of visual field (VF) and visual acuity (VA) 1 year after surgery in chiasmal compression patients presenting with visual impairment. PATIENTS AND METHODS: Twenty-nine eyes of 16 patients with chiasmal compression and 14 eyes of 14 control subjects were enrolled. All patients undergoing chiasmal decompression surgery via a transsphenoidal approach were prospectively evaluated before and 1 year after surgery with best corrected visual acuity (BCVA, logMAR), mean deviation (MD) value with standard automated perimetry (SAP) and RNFL thickness with optical coherence tomography. Eyes with chiasmal compression were divided into two groups according to the mean preoperative RNFL thickness: ≥ 100 µm (Group 1) and < 100 µm (Group 2). The relationship between the mean preoperative RNFL thickness and visual prognosis parameters (VF, VA) was analyzed. RESULTS: The mean preoperative RNFL thickness was 115.92 ± 8.97 µm, 84.0 ± 8.85 µm, and 114.21 ± 7.75 µm in Group 1 (n = 15 eyes), Group 2 (n = 14 eyes) and the control group (n = 14 eyes), respectively. The mean preoperative BCVA was 0.15 ± 0.3 in Group 1, and 0.41 ± 0.39 in Group 2. The mean BCVA increased to 0.03 ± 0.1 in Group 1 in the postoperative period but did not change in Group 2. MD value was - 6.10 ± 5.54 in the preoperative period and - 2.59 ± 2.23 in the postoperative period for Group 1 (p = 0.014), while it was - 18.97 ± 4.14 in the preoperative period and - 18.57 ± 4.51 in the postoperative period in Group 2 (p = 0.24). CONCLUSIONS: This study suggests that lower mean preoperative RNFL thickness was associated with poorer long-term visual prognosis. Preoperative RNFL thickness measurements may be helpful in predicting the recovery of VF and VA after decompression surgery in patients with chiasmal lesion presenting with visual impairment.

Functional Prognostic value of optical coherence tomography in optic chiasmal decompression: A preliminary study.

PURPOSE: To assess the predictive value for functional recovery of Ganglion Cell Complex Layer (GCC) and Retinal Nerve Fiber Layer (RNFL) measurements obtained by Optical Coherence Tomography (OCT) in patients undergoing chiasmal decompression and to define potential OCT thresholds for visual recovery. METHODS: We measured preoperative GCC and RNFL thickness in patients with a sellar and/or perisellar tumor compressing the optic chiasm. Visual recovery was defined as recovery of mean deviation (MD) and pattern standard deviation (PSD) using Humphrey visual field testing after 12 successful decompressions (24 eyes). Receiver operating characteristic curve (ROC) analysis was used to identify the best thresholds. RESULTS: Robust global and focal OCT thresholds were found. Superior GCC≥63µm had the best functional prognostic value (AUC=1) for visual improvement. Mean GCC ≥ 67µm and mean RNFL≥75µm also had excellent predictive values (AUC>0.9). CONCLUSION: In this preliminary study, significant preoperative OCT thresholds for early visual recovery after chiasmal decompression were identified, mainly regarding GCC measurements. Further studies on larger cohorts with closely scheduled follow-up could refine our results.

Parafoveal and Peripapillary Perfusion Predict Visual Field Recovery in Chiasmal Compression due to Pituitary Tumors.

BACKGROUND: To evaluate the potential of vessel density alterations for predicting postoperative visual field (VF) improvement in chiasmal compression using optical coherence tomography angiography (OCT-A). METHODS: The study investigated 57 eyes of 57 patients diagnosed with pituitary tumors and 42 eyes of 42 age and refractive error matched controls. All eyes with chiasmal compression for which preoperative optical coherence tomography (OCT) and OCT-A, and pre- and postoperative VF data were available. Preoperative vessel densities of superficial retinal capillary plexus (SRCP), deep retinal capillary plexus (DRCP), and radial peripapillary capillary (RPC) segment were utilized by OCT-A. RESULTS: Preoperative peripapillary retinal nerve fiber layer and ganglion cell layer complex thickness and vessel densities of SRCP and RPC segments in eyes with chiasmal compression were significantly reduced compared with healthy controls (p < 0.001, p < 0.001, p = 0.007, and p = 0.020, respectively). In multivariate regression analysis, preoperative perimetric mean deviation (MD) (p = 0.002) and vessel density of SRCP (p = 0.025) were correlated significantly with postoperative perimetric MD. Spearman's correlation analysis revealed significant correlations between preoperative MD on perimetry (r = 0.443, p = 0.001), vessel densities of SRCP (r = 0.288, p = 0.035) and RPC segment (r = 0.347, p = 0.009), and postoperative perimetric MD. CONCLUSIONS: Structural degeneration referred to as microvascular alterations measured by OCT-A and preoperative VF defects were associated with worse postoperative VF prognosis. Parafoveal and peripapillary vessel densities may serve as a sensitive, structural prognostic factors in the preoperative judgement of chiasmal compression.

Optical coherence tomography analysis of inner and outer retinal layers in eyes with chiasmal compression caused by suprasellar tumours.

PURPOSE: To compare postoperative macular thickness measurements of inner and outer retinal layers in eyes of patients with chiasmal compression with or without visual field (VF) recovery and healthy controls using optical coherence tomography (OCT). METHODS: Macular spectral-domain OCT has been used for the auto-segmentation of images obtained from 100 eyes affected with chiasmal compression compared with 100 healthy controls enrolled in this study. We have divided eyes with chiasmal compression into two groups: group 1 characterized by VF recovery after tumour excision and group 2 showing partial or no recovery of VF. The thickness of the macular retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor layer (PRL), inner retinal layer (IRL) and outer retinal layer (ORL) was segmented. The correlation between macular RNFL (mRNFL) and functional parameters has been analysed. RESULTS: Both groups 1 and 2 showed significant thinning of RNFL, GCL, IPL and IRL in all quadrants. However, no significant changes have been detected in PRL and ORL of patients in either group compared with healthy controls. A significant thickening was detected in INL and ONL of group 2 compared with healthy controls and group 1. Postoperative mRNFL thickness is significantly correlated with VF defects and visual acuity except temporal quadrant. CONCLUSIONS: Eyes with chiasmal compression showed thinning of the inner retinal layers with thickening of the INL and ONL in patients with partial to no recovery of VF. The changes in retinal microstructures are well-correlated with functional recovery. Further studies are needed to reveal the clinical implications of these findings in patients with chiasmal compression.

Short-Listing the Program Choice for Perimetry in Neurological Conditions (PoPiN) Using Consensus Methods.

BACKGROUND: Neurological conditions frequently cause visual field loss, commonly resulting in perimetry requests for suspected or known conditions. Currently there are no national guidelines for perimetry in neurological conditions. A wide choice of perimetry programs exists. An inappropriate program choice could fail to detect visual field loss. Two phases in this study determined preference of perimetry programs for detection of visual field loss in four common neurological conditions (idiopathic intracranial hypertension (IIH), optic neuropathies, chiasmal compression and stroke), to aid the design of research and clinical practice guidelines. METHODS: A survey consisted of 47 perimetry programs. Orthoptists and neuro-ophthalmologists were asked which perimetry programs they considered important for use in the four neurological conditions. These programs were short-listed for discussion in a consensus meeting. A nominal group technique was used for the consensus meeting to reach consensus on the three most favoured perimetry programs appropriate for the four conditions. RESULTS: Twenty-six participants completed the survey (51% return rate). Nine programs were found to be not applicable to any of the conditions. The short-lists for the conditions varied between six and ten perimetry programs. Seven participants discussed the survey results at a consensus meeting to agree the three most favoured perimetry programs for IIH, optic neuropathy and chiasmal compression (manual/semi manual kinetic, static 30-2 and full-field 120) and for stroke (manual/semi manual kinetic, static 30-2 and monocular Esterman). CONCLUSION: A wide range of perimetry programmes were explored thoroughly through survey and consensus methods in order to determine clinician preference for their use in neuro-ophthalmic practice. The three most favoured perimetry programs for the four conditions was established.

Predictive value of preoperative retinal nerve fiber layer thickness for postoperative visual recovery in patients with chiasmal compression.

The aim of this study was to evaluate the predictive role of preoperative retinal nerve fiber layer (RNFL) thickness for postoperative visual recovery in patients with chiasmal compression through performing a meta-analysis. PubMed, EMBASE, Cochrane Library and China National Knowledge Infrastructure were searched for relevant studies. The study and patient characteristics were extracted. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to estimate the predictive value of RNFL thickness. Subgroup analyses were also performed. Four studies with 202 patients and 395 eyes were included. The pooled results showed that patients with normal RNFL thickness could achieve better visual recovery compared with those with thin RNFL with the OR of 15.61 (95% CI, 4.09-59.61). Significant heterogeneity was observed (I2 = 54.5%, P=0.086). Publication bias was not present. Normal preoperative RNFL thickness could predict better postoperative visual recovery than thin RNFL in patients with chiasmal compression.

Morphological and Functional Inner and Outer Retinal Layer Abnormalities in Eyes with Permanent Temporal Hemianopia from Chiasmal Compression.

PURPOSE: The aims of this study are to compare optical coherence tomography (OCT)-measured macular retinal layers in eyes with permanent temporal hemianopia from chiasmal compression and control eyes; to compare regular and slow-flash multifocal electroretinography (mfERG) in patients and controls; and to assess the correlation between OCT, mfERG, and central visual field (SAP) data. METHODS: Forty-three eyes of 30 patients with permanent temporal hemianopia due to pituitary tumors who were previously submitted to chiasm decompression and 37 healthy eyes of 19 controls were submitted to macular spectral domain OCT, mfERG, and 10-2 SAP testing. After segmentation, the thickness of the macular retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer, and photoreceptor layer (PRL) was measured. Amplitudes and oscillatory potentials (OPs) were measured on regular and slow-flash mfERG, respectively, and expressed as the mean values per quadrant and hemifield. RESULTS: RNFL, GCL, and IPL thickness measurements were significantly reduced in all quadrants, whereas INL, OPL, and PRL thicknesses were significantly increased in the nasal quadrants in patients compared to those in controls. Significant correlations between OCT and 10-2 SAP measurements were positive for the RNFL, GCL, and IPL and negative for the INL, OPL, and PRL. OPs and mfERG N1 amplitudes were significantly reduced in the nasal hemiretina of patients. Significant correlations were found between OP and mfERG amplitudes for inner and outer nasal hemiretina OCT measurements, respectively. CONCLUSION: Patients with permanent temporal hemianopia from previously treated chiasmal compression demonstrated significant thinning of the RNFL, GCL, IPL, and thickening of the INL, OPL, and PRL associated with reduced OP and mfERG N1 amplitudes, suggesting that axonal injury to the inner retina leads to secondary damage to the outer retina in this condition.

Evaluation of Retinal Nerve Fiber Layer Thickness in Acromegalic Patients Using Spectral-Domain Optical Coherence Tomography.

PURPOSE: To evaluate retinal nerve fiber layer (RNFL) thickness in acromegalic patients. METHODS: A study group of 29 patients with acromegaly and a control group of 38 age-matched healthy individuals were enrolled in a cross-sectional study. The study group was further divided by tumor size into two subgroups, a macroadenoma group and a microadenoma group. Serum growth hormone (GH) and insulin-like growth factor-1 (IGF-I) levels were detected at the time of ophthalmological examination in the study group. In both the study and control group, the RNFL thickness in the four quadrants was measured by optical coherence tomography. The relationship between GH and IGF-I levels and RNLF thickness was also evaluated. RESULTS: The difference in mean RNLF thickness in all quadrants between the study and control groups was not statistically significant. In acromegalic patients with macroadenoma, the mean RNLF thickness of the inferior quadrant decreased significantly compared to both patients with microadenoma and healthy individuals (p = 0,032 and p = 0,046). GH and IGF-1 levels were not significantly correlated with the RNLF thickness in the study group. CONCLUSIONS: Excessive GH and IGF-1 levels do not affect the optic nerve or RNLF thickness, whereas the RNLF becomes thinner in the inferior quadrant in acromegalic patients with macroadenoma as a result of the chiasmal compression.

Multi-scale analysis of optic chiasmal compression by finite element modelling.

The precise mechanism of bitemporal hemianopia (a type of partial visual field defect) is still not clear. Previous work has investigated this problem by studying the biomechanics of chiasmal compression caused by a pituitary tumour growing up from below the optic chiasm. A multi-scale analysis was performed using finite element models to examine both the macro-scale behaviour of the chiasm and the micro-scale interactions of the nerve fibres within it using representative volume elements. Possible effects of large deflection and non-linear material properties were incorporated. Strain distributions in the optic chiasm and optic nerve fibres were obtained from these models. The results of the chiasmal model agreed well with the limited experimental results available, indicating that the finite element modelling can be a useful tool for analysing chiasmal compression. Simulation results showed that the strain distribution in nasal (crossed) nerve fibres was much more nonuniform and locally higher than in temporal (uncrossed) nerve fibres. This strain difference between nasal and temporal nerve fibres may account for the phenomenon of bitemporal hemianopia.

Visual acuity and pattern of visual field loss at presentation in pituitary adenoma.

Our purpose was to analyse the demographics, prevalence and pattern of visual field defects in patients with pituitary adenoma. We prospectively recruited 103 consecutive patients (206 eyes) presenting to a neurosurgical unit with pituitary adenoma. Ophthalmological examination and standard automated perimetry (Humphrey, 24-2 threshold) was performed. Severity of visual field defects was also assessed. The mean population age was 53.9 years (standard deviation=15). Visual loss was the most common reason for presentation (39%) followed by endocrine abnormality (21%) and headache (15%). Patients with endocrine abnormality on presentation were 10.9 years younger than those presenting with visual loss (p=0.001). Bitemporal defects were the most prevalent pattern (n=22, 41%) followed by homonymous defects (n=7, 13%). Of the patients with visual field loss, 33% had unilateral visual field defects. The mean visual acuity in those with bitemporal defects was 6/7.5 with half of these patients having 6/6 vision in both eyes. In conclusion, the majority of patients with pituitary adenoma have visual acuity better than 6/7.5 despite having visual field defects. While a bitemporal pattern of visual field loss is the most common, a significant proportion of patients had unilateral and altitudinal defects. Assessment of the visual field is essential to rule out chiasmal compression.