12-month outcomes of ab interno excisional goniotomy combined with cataract surgery in primary open-angle glaucoma and normal tension glaucoma.

PURPOSE: To evaluate the efficacy and safety of excisional goniotomy performed with the Kahook Dual Blade (KDB) combined with cataract surgery in patients with pimary open angle glaucoma (POAG) and Normal Tension Glaucoma (NTG) under topical therapy. Further sub-analysis was performed to compare between 90 and 120 degrees goniotomy. METHODS: This was a prospective case series of 69 eyes from 69 adults (age 78 ± 5.9 years; male = 27, female = 42). Indications for surgery included insufficient IOP control with topical medication, glaucomatous damage progression under topical therapy and reduction of medication burden. Complete success was defined as IOP lowering below 21 mmHg without the need for topical medication. For NTG patients, complete success was defined as IOP lowering below 17 mmHg without the need for topical medication. RESULTS: IOP was significantly lowered from 19.7 ± 4.7 to 15.1 ± 2.7 at 2 months, 15.8 ± 2.3 at 6 months and 16.1 ± 3.2 at 12 months (p < 0.05) for POAG and 15.1 ± 2.5 to 14.1 ± 2.4 at 2 months, 14.1 ± 3.1 at 6 months and 13.6 ± 1.8 at 12 months (p > 0.08) for NTG, respectively. Complete success was achieved in 64% of the patients. IOP lowering under 17 mmHg without the need for topical medication was achieved in 60% of the patients at 12 months. In NTG patients (14 eyes) IOP lowering under 17 mmHg without the need for topical medication was achieved in 71%. No significant difference was recorded in terms of IOP lowering at 12 months in-between 90° and 120° of treated trabecular meshwork (p > 0.7). No severe adverse reactions were recorded in this study. CONCLUSION: One-year results show that KDB combined with cataract surgery is an effective treatment option for glaucoma patients. IOP lowering was successfully achieved in NTG patients with complete success in 70% of the patients. In our study, no significant differences were recorded in-between 90° and 120° of treated trabecular meshwork.

Choroidal hypoperfusion: an indicator of low tension neovascular glaucoma.

PURPOSE: To report a case of low tension neovascular glaucoma in ocular ischemic syndrome. METHODS: An elderly man presenting with vision loss after an episode of hemiparesis was investigated to look for the cause of vision loss and treated. RESULTS: Fluorescein angiography demonstrated poor uveal perfusion and treatment with panretinal photocoagulation led to rapid closure of the angle. CONCLUSION: This case highlights the typical ophthalmic features of ocular ischemic syndrome and emphasizes the necessity of patient education and prognostication.

[The Keyrole of Multiomics in the Predictive, Preventive and Personalised Medical Approach towards Glaucoma Management]. / Die Schlüsselrolle der Multiomics in Prädiktion, Prävention und personalisierter Behandlung vom Glaukom.

Glaucoma is the second leading cause of blindness, with altogether about 70 million patients registered worldwide. These facts prompt us to reconsider currently applied concepts in overall glaucoma management. Innovative strategies of predictive, preventive and personalised medicine (PPPM) are expected to considerably improve disease prevention and personalised treatment. The comprehensive PPPM measures include the application of individualised patient profiles, "phenotyping", molecular characterisation of the pre-lesions and disease stages, innovative screening programs, patient stratification, early and predictive diagnosis, targeted prevention, and the creation of personalised treatment algorithms. The main stakeholders are glaucoma-dedicated researchers, ophthalmologists, general practitioners, groups at risk, specialised medical units, affected patients and their family members, insurances, policy makers, and the diagnostic and pharmaceutical industries. Potential beneficiaries include these groups as well as society as a whole, due to financial savings in the healthcare expected.

Clinical Features of Japanese Patients with Central Retinal Vein Occlusion Complicated by Normal-Tension Glaucoma: A Retrospective Study.

PURPOSE: The association of central retinal vein occlusion (CRVO) with primary open-angle glaucoma (POAG) or ocular hypertension has been reported, and lowering intraocular pressure (IOP) helps to improve the retinal circulation in eyes with CRVO. However, the clinical features of CRVOs with normal-tension glaucoma (NTG) are not well known. Therefore, we investigated Japanese CRVO patients with NTG. METHODS: We retrospectively investigated 234 CRVO patients over 5 years, with follow-ups of more than 12 months, and evaluated the prevalence of glaucoma. RESULTS: Of the 234 CRVO patients, 18 (7.7%) were diagnosed with NTGs (n = 10) or POAGs (n = 8). Seven POAG (87.5%) and 3 NTG (30%) patients had systemic hypertension. At the initial CRVO evaluation, 6 NTGs showed a significantly increased IOP; mean IOP was 13.3 mm Hg before CRVO, 16.2 mm Hg at CRVO, and 13.5 mm Hg at the final visit. CONCLUSIONS: The proportion of NTGs with systemic hypertension was low. IOP of NTG patients was significantly elevated at the initial CRVO evaluation, even in the presence of anti-glaucoma drugs.

Management of Blood Pressure in Patients with Glaucoma.

PURPOSE OF REVIEW: Ocular perfusion pressure (OPP) is defined as the difference between BP and intraocular pressure (IOP). With low BP comes low OPP and resultant ischemic damage to the optic nerve, leading to glaucoma progression. The purpose of this article is to review the literature on BP as it relates to glaucoma and to create a forum of discussion between ophthalmologists and internal medicine specialists. RECENT FINDINGS: Both high and low BP has been linked glaucoma. Low BP is particularly associated with glaucoma progression in normal-tension glaucoma (NTG) patients. Patients who have low nighttime BP readings are at highest risk of progression of their glaucoma. Internal medicine specialists and ophthalmologists should consider the relationship between BP and glaucoma when treating patients with concomitant disease. Too-low nighttime BP should be avoided. Ambulatory blood pressure monitoring is a useful tool to identify patients at greatest risk for progression.

Normal-tension glaucoma and obstructive sleep apnea syndrome: a prospective study.

BACKGROUND: Today, identified risk factors for normal-tension glaucoma (NTG) include abnormal ocular blood flow, abnormal blood coagulation, systemic hypotension, ischemic vascular disorders, and autoimmune diseases. However, pathogenesis of the condition remains unclear. On the other hand, there are also a few studies suggesting that the obstructive sleep apnea syndrome (OSAS) may compromise optic nerve head perfusion and cause glaucomatous optic neuropathy by creating transient hypoxemia and increasing vascular resistance. In this study, we evaluated the possible association between OSAS and NTG. METHODS: We recruited 24 patients with NTG and 24 age and sex matched controls who were also similar for systemic risk factors such as diabetes mellitus (DM), hypertension (HT) and hypercholesterolemia. All patients and controls underwent over-night polysomnography (PSG) for the diagnosis of OSAS and calculation of Apnea-Hypopnea Index (AHI). RESULTS: Patients and controls were statistically similar in terms of age, sex, gender, smoking, systemic risk factors, neck circumference and body mass index. The subjects with AHI ≥ 20 were accepted as OSAS. Ten (41.7%) of 24 patients with NTG and 3 (12.5%) of 24 controls had OSAS (p < 0.05). CONCLUSIONS: The prevalence of OSAS was higher in patients with NTG and the difference between patient and control groups was statistically significant (p < 0.05).

''The association of normal tension glaucoma with Buerger's disease: a case report''.

BACKGROUND: To report a case of a 48-year-old man with Buerger's disease who presented with bilateral normal-tension glaucoma (NTG). CASE PRESENTATION: A 48-year-old man who had been diagnosed with Buerger's disease 12 years ago, and received bilateral below-the-knee amputations for ischemic ulcers of the lower limbs, presented at our clinic due to a sudden loss of visual acuity in the left eye. A fundus exam revealed a cup-to-disc ratio of 0.5 for the right eye and 0.8 for the left eye, arteriolar constriction in both eyes, retinal edema in the inferopapillary area, and splinter hemorrhages and soft exudate in the left eye. We diagnosed the patient as having acute nasal branch retinal artery occlusion in the left eye and bilateral NTG, as a result of the ophthalmologic examination and the other findings. CONCLUSION: Although the pathomechanism of NTG is still unknown, previous studies have suggested that patients with NTG show a higher prevalence of vasospastic disorders. We present the second report of NTG associated with Buerger's disease to be described in the literature.

Low nocturnal ocular perfusion pressure as a risk factor for normal tension glaucoma.

OBJECTIVES: In the absence of raised intraocular pressure (IOP), haemodynamic parameters have been implicated in the development of normal tension glaucoma (NTG). The purpose of this study is to compare 24-hour IOP and haemodynamic parameters in NTG patients and non-glaucoma patients. METHODS: This is a cross sectional study involving 72 NTG patients from University of Malaya Medical Centre eye clinic glaucoma registry. The non-glaucoma patients were volunteers selected from eye clinic patients. All enrolled patients underwent 24-hour IOP and blood pressure monitoring via 2-hourly IOP and blood pressure (BP) measurements. All readings were taken in the sitting position during the diurnal period and in the supine position during the nocturnal period RESULTS: Comparison of the haemodynamic parameters, the nocturnal mean systolic BP, nocturnal mean diastolic BP and nocturnal mean arterial pressure (MAP) were significantly lower in the NTG group. The systemic ocular perfusion pressures (OPP), diastolic OPP and mean OPP taken at night were also significantly lower in the NTG group. The differences between the groups were still manifest after controlling for age and presence of hypertension. CONCLUSION: Our findings show that the nocturnal supine blood pressure parameters (systolic, diastolic and mean) and OPP were significantly lower in the NTG group compared to normals. This may reflect defective autoregulatory mechanisms in NTG patients.

[A challenge to primary open-angle glaucoma including normal-pressure. Clinical problems and their scientific solution].

Primary open-angle glaucoma (POAG), including normal-tension glaucoma (NTG), is reported by the Tajimi Study to afflict 3.9% of the total population, and this represents about 80% of all total glaucoma cases which, in total, afflict 5.0% of the population. We tried to analyze the clinical problems relating to POAG by looking at the pathogenesis, intraocular pressure (IOP), therapy, neuroprotection and surgery of the disease. To elucidate the pathogenesis of glaucoma progression, we measured retinal nerve fiber layer defect (RNFLD) angles', and divided the NTG cases into 2 groups, enlarged RNFLD and stable RNFLD. Disc hemorrhages were found to be significantly more frequent in the enlarged group than in the stable group. RNFLD was enlarged in the direction of disc hemorrhage in over 80% of the eyes. In the majority of the eyes of the enlarged group, the enlargement of RNFLD was toward the fovea. The enlargement of RNFLD in NTG was closely associated with disc hemorrhage and the deterioration of the visual field. We developed a simultaneous structure and function evaluation technique combining spectral-domain (SD) optical coherence tomography (OCT) and fundus-oriented perimeters for the detection of visual field abnormalities in the RNFLD area. We superimposed the ganglion cell complex map obtained by SD-OCT on the fundus-oriented perimeter image. We observed very early or preperimetric normal pressure glaucoma as well as disc hemorrhage adjacent to the borders of the RNFLD. The borderline of the RNFLD seemed to be the thinnest RNFL and had the lowest retinal sensitivity (Active site for RNFLD progression). To clarify the role of the circadian clock genes in the generation of a 24-hour IOP rhythm, we used the microneedle method to measure the IOP at eight time points daily, both in wild type mice and Cry-deficient (Cry 1-/-Cry 2-/-) mice. In the wild-type mice living in light-dark conditions, the pressure measured in the light phase was significantly lower than in the dark phase. This biphasic daily rhythm was maintained under dark-dark conditions. In contrast, the Cry-deficient mice did not show significant circadian changes in their IOP, regardless of the environmental light conditions. These findings demonstrate that clock genes are essential for the generation of the circadian rhythm of IOP. We evaluated the relationship between the genetic polymorphisms of the adrenergic receptor (ADR) and the diurnal IOP in untreated NTG patients. For Del 301-303 in α2B-ADR, De1322-325 in α2C-ADR, and S 49G (A/G) in ßl-ADR, the major homozygotes and minor carriers had parallel diurnal IOP curves, but significantly different diurnal IOP levels. Polymorphisms of the ADR gene may predict the diurnal IOP level of patients with NTG. Looking toward the future, tailor-made medicine in glaucoma therapy, we evaluated the relationship between the polymorphisms of the prostaglandin F2α, receptor (FP receptor) gene and the effectiveness of topical latanoprost treatment in 100 normal volunteers. One SNP(rs3753380) was located in the promoter region of the FP receptor gene and was significantly correlated with % IOP reduction. Two SNPs, rs3753380 and rs3766355 (an SNP in intron 1), were associated with the degree of response to latanoprost. The genotype of these SNPs may be an important determinant of variability in response to latanoprost. To investigate the predictability of IOP response of the fellow eye in a one-eye trials, we compared the correlation of the fellow-eye's IOP response in one-eye trials performed separately for each eye with that of bilateral treatment in 41 normal subjects. Correlation of mean diurnal IOP reduction between 2 one-eye trials was poor (r2 = 0.102), even after subtracting the nontreated eye IOP fluctuations from the treated eye IOPs (r2 = 0.097), but that between fellow eyes in bilateral treatment was excellent (r2 = 0.849). Therefore, we examined the effects of multiple IOP measurements on the correlation of response to glaucoma medication between fellow eyes. Latanoprost was applied to the first eye and then to both eyes of POAG or ocular hypertension patients. IOP measurements were performed twice on different days at baseline, during treatment of the first eye only and for both eyes. No significant correlations of ΔIOP 1 (IOP at baseline-IOP after treatment) between fellow eyes were found. ΔIOP 2 (ΔIOP 1-IOP fluctuation of the contralateral eye) was significantly correlated between the fellow eyes using two post-treatment IOP measurements. Using multiple IOP measurements may improve the prediction of a fellow eye's response to glaucoma medication in one-eye trials. We used a scanning laser ophthalmoscope (SLO) for in vivo imaging and counting of rat retinal ganglion cells (RGCs). RGC survival decreased gradually after crushing the optic nerve. RGC counts by SLO were comparable to those in retinal flat mounts. We developed OCT system for rat eyes. The mean retinal nerve fiber layer (RNFL) thicknesses in the circumpapillary OCT scans were unchanged 1 week after crushing the optic nerve, but then decreased significantly and progressively after the second week. RNFL thicknesses in OCT images correlated significantly with thicknesses determined histologically. SLO and OCT will be useful for evaluating the effects of neuroprotective drugs. We developed a new glaucoma filtration surgery system using a thin honeycomb-patterned biodegradable film in rabbits. The film had a honeycomb-patterned surface that faced the subconjunctival Tenon tissue, while the other side was smooth. Postoperative IOPs of the film-treated eyes were significantly lower than those of the control eyes, but were not significantly different from those of the MMC-treated eyes. The thin honeycomb-patterned film that was attached to the inner bleb wall worked as an adhesion barrier in glaucoma filtration surgery in rabbits.

Changes in optic nerve head blood flow, visual function, and retinal histology in hypercholesterolemic rabbits.

We investigated the effects of hypercholesterolemia on optic nerve head (ONH) blood flow, visual function, and retinal histology in a rabbit model. Hypercholesterolemia was induced in rabbits by feeding them a high cholesterol (1%) diet for 12 weeks. Changes in blood pressure, intraocular pressure (IOP), and ONH blood flow were monitored at 6 and 12 weeks after treatment. The autoregulation of ONH blood flow as detected by laser speckle flowgraphy was verified by an artificial elevation of IOP at 12 weeks. Visually evoked potentials (VEPs) were also recorded and analyzed at 6 and 12 weeks. Finally, a histological examination as well as immunohistochemistry to endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) was performed. In the hypercholesterolemic rabbits, blood pressure, IOP, and ONH blood flow did not alter significantly throughout this study. The autoregulation of ONH blood flow against IOP elevation was found to be impaired at 12 weeks. The amplitudes of the first negative peak of VEPs were diminished. Both the density of the retinal ganglion cells and the thickness of the inner nuclear layer and photoreceptor cell layer were reduced. Immunoreactivity to eNOS was reduced and that to iNOS was enhanced in the hypercholesterolemic rabbits compared to those in the normal control rabbits. The results of this study show that hypercholesterolemia induces impairment in the autoregulation of ONH blood flow and deterioration in visual function and histology. Downregulation of eNOS activity might be one of the causes for impairment of the autoregulation. Enhanced activity of iNOS might be involved in the impaired visual function and histology.

[Optic neuropathies of different etiology and normal tension glaucoma: the point of differential diagnosis].

62 patients (109 eyes) with glaucoma-like optic nerve head cupping and normal IOP indices (Po not more than 21 mm Hg) were examined to find the etiology of optic nerve changes. Regarding corneal biomechanics new-onset primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG) were diagnosed in 27% and 3% of examined patients respectively. In 59% of patients optic neuropathy (ON) of different etiology was found to be the cause of glaucoma-like optic nerve changes including compression ON due to lesion of intracranial portion of optic nerve and chiasma in 6% of cases. In 11% physiologic large optic nerve head cupping with normal visual functions and absence of nerve fiber structural changes was found.

Predicting the development of normal tension glaucoma and related risk factors in normal tension glaucoma suspects.

This study investigated the predicted risk factors for the development of normal-tension glaucoma (NTG) in NTG suspects. A total of 684 eyes of 379 NTG suspects who were followed-up for at least 5 years were included in the study. NTG suspects were those having (1) intraocular pressure within normal range, (2) suspicious optic disc (neuroretinal rim thinning) or enlarged cup-to-disc ratio (≥ 0.6), but without definite localized retinal nerve fiber layer (RNFL) defects on red-free disc/fundus photographs, and (3) normal visual field (VF). Demographic, systemic, and ocular characteristics were determined at the time of the first visit via detailed history-taking and examination of past medical records. Various ocular parameters were assess using spectral-domain optical coherence tomography and Heidelberg retinal tomography. Conversion to NTG was defined either by the presence of a new localized RNFL defect at the superotemporal or inferotemporal region on disc/fundus red-free photographs, or presence of a glaucomatous VF defect on pattern standard deviation plots on two consecutive tests. Hazard ratios were calculated with the Cox proportional hazard model. In total, 86 (12.6%) of the 684 NTG suspects converted to NTG during the follow-up period of 69.39 ± 7.77 months. Significant (P < 0.05, Cox regression) risk factors included medication for systemic hypertension, longer axial length, worse baseline VF parameters, thinner baseline peripapillary RNFL, greater disc torsion, and lamina cribrosa (LC) thickness < 180.5 µm (using a cut-off value obtained by regression analysis). Significant (P < 0.05, Cox regression) risk factors in the non-myopic NTG suspects included medication for systemic hypertension and a LC thinner than the cut-off value. Significant (P < 0.05, Cox regression) risk factors in the myopic NTG suspects included greater disc torsion. The results indicated that 12.6% of NTG suspects converted to NTG during the 5-6-year follow-up period. NTG suspects taking medication for systemic hypertension, disc torsion of the optic disc in the inferotemporal direction, and thinner LC of the optic nerve head at baseline were at greater risk of NTG conversion. Related baseline risk factors were different between myopic and non-myopic NTG suspects.

The role of pattern electroretinograms and optical coherence tomography angiography in the diagnosis of normal-tension glaucoma.

In this study, we investigated the correlation between pattern electroretinogram (PERG) and optical coherence tomography angiography (OCTA) parameters for diagnosis in patients with normal-tension glaucoma (NTG). Forty-nine normal individuals (49 eyes) and 60 patients with NTG (60 eyes) were enrolled. OCTA and PERG parameters, such as macular vessel density (VD) and the amplitude of N35-P50 and P50-N95, were measured. Correlation analyses were performed between the parameters, and the area under the curve (AUC) was used to identify their diagnostic ability for NTG. Macular VD and the amplitude of N35-P50 and P50-N95 showed significant differences between the normal individuals and patients with NTG. Correlation between P50 and N95 amplitude and macular VD was significant in the normal and early glaucoma groups. Macular VD showed a higher AUC value (0.730) than that of P50-N95 amplitude (0.645) in the early glaucoma group. In the moderate to severe glaucoma group, the AUC value of the amplitude of P50-N95 (0.907) was higher than that of macular VD (0.876). The results indicate that PERG and OCTA parameters may identify glaucoma in its early stage, based on the severity of glaucomatous damage in patients with NTG.

What is glaucomatous optic neuropathy?

Glaucomatous optic neuropathy (GON) is the pathohistological feature of glaucoma in the optic nerve. The pathogenesis of GON has been hypothesized, to either originate from compromised mechanical conditions at the lamina cribrosa or as associated with pathological vascular involvement. From a historical perspective, glaucoma is the degeneration of retinal ganglion cells (RGC) due to the elevation of intraocular pressure (IOP). The consensus of glaucoma treatment is generally accepted as sufficient IOP reduction. Is there an additional option to treat GON from the perspective of the vascular theory? In this section, two distinguished leaders in glaucoma research advance their views and discuss the current opinions surrounding the two theories regarding the causes of GON in primary open angle glaucoma (POAG) and normal tension glaucoma (NTG).

Results of Neuroimaging in Patients with Atypical Normal-Tension Glaucoma.

AIM: The aim of the study was to determine the frequency of pathologies which can mimic normal-tension glaucoma (NTG), observed in neuroimaging of NTG patients, and to evaluate the frequency of pathologies in determined additional indications for neuroimaging. Material and Methods. The studied group consisted of 126 NTG patients who met at least one of the following criteria: unilateral NTG, damage in the visual field (VF) inconsistent with optic disc appearance, fast VF progression, worsening of visual acuity, predominant optic disc pallor rather than optic disc excavation, diagnosis under the age of 50, and scotoma in VF restricted by a vertical line. The patients included in the research underwent MRI scans of the brain and both orbits. RESULTS: After neuroimaging, the results of 29 (23%) patients were qualified as positive; 18 (14.2%) of the identified pathologies were found to clinically affect the visual pathway. The most frequent brain pathology was intracranial meningiomas, observed in 4 patients (3.1%), followed by optic nerve sheath meningiomas diagnosed in 3 cases (2.4%), and brain glioma in 1 patient (0.8%). Pituitary gland adenomas were described in 6 patients (4.5%); 3 of the tumours were in contact with the optic chiasm. 53 (40%) patients had minimal ischemic changes in different regions of the brain. In the case of worsening BCVA or fast VF progression, the frequency of positive results was the highest (50% and 40%), whereas in the case of diagnosis at a young age and unilateral involvement, neuropathology was the rarest (0% and 6.9%). CONCLUSIONS: In the case of NTG, the decision to perform neuroimaging should be made after a detailed assessment of clinical status, rather in the event of finding the signs of possible compressive optic neuropathy than as an obligatory procedure for every patient.

Is "normal tension glaucoma" glaucoma?

Primary open angle glaucoma (POAG) represents a distinct disease entity with elevated intraocular pressure (IOP) as the main risk factor, even though the reasons for why the IOP is elevated remains to be elucidated. It is considered that normal tension glaucoma (NTG) is a subtype of POAG, comprising a special form of glaucomatous neurodegeneration or glaucomatous optic neuropathy (GON) almost exactly the same as that seen in POAG, but the IOP, as named, remains in the statistically normal range. Actually the disease entity of NTG has been a profound confusion and it is difficult to be accurately conceptualized. One of the reasons is that the IOP is closely linked to the occurrence of GON in POAG but not in NTG, and for the latter, it seems that GON is secondary to a number of local or systemic disorders. In recent years, increasing evidences suggest that NTG or IOP independent GON is a non-glaucomatous disease with different disease entities from POAG and with more diverse and complex etiologies. Here we hypothesized that NTG, at least for those with recognizable primary diseases, is not a glaucomatous disease; instead, it represents a group of disorders with GON as a characteristic clinical feature or phenotype.

Glaucoma in patients with shunt-treated normal pressure hydrocephalus.

OBJECTIVE: Changes in the pressure gradient between intraocular and intracranial compartments at the lamina cribrosa level are a possible explanation of normal tension glaucoma (NTG). Shunt-treated normal pressure hydrocephalus (NPH) is a model for testing whether the increase (time from disease onset to CSF shunt placement, i.e., "protection period") and decrease (time from shunt placement to observation, i.e., "exposure period") in intracranial pressure (ICP) are glaucoma protective or risk factors, respectively. The authors estimated the prevalence of NTG in patients with shunt-treated NPH and calculated the extent of optic nerve exposure to changes in the trans-lamina cribrosa gradient. METHODS: Data obtained in patients with NPH who had undergone ventriculoperitoneal (VP) shunt placement were analyzed. Patients with more than 6 months' follow-up, no pathologies associated with ICP changes or CSF dynamics disturbances, and no surgical or valve-related complications were scheduled for ophthalmic evaluation. RESULTS: Nine of 22 patients had NTG, which is about a 40-fold increase in rate compared with the rate in the general elderly population without hydrocephalus (p < 0.001). The median protection period was 12.0 months in patients with NTG and 18.0 months in those without NTG (p = 0.033). The median ICP decrease multiplied by duration of exposure in months was 76.0 mm Hg × months in the NTG group and 24.1 mm Hg × months in the no-NTG group (p = 0.048). The patients' median adjusted age (adjusted for "protection" and "exposure" times) was 85.1 years in the NTG group and 78.8 years in the no-NTG group (p = 0.001). CONCLUSIONS: A crucial risk factor for development of NTG in patients with shunt-treated NPH is the duration of optic nerve exposure to the lowering of ICP. Patients with NPH who are candidates for CSF shunting should be informed of the risk of incurring glaucoma. Longitudinal studies could provide estimates of tolerated times for a given ICP decrease.

A Case of Glaucoma in Hereditary Spherocytosis.

PURPOSE: To report a case of glaucoma and the inherited red cell membranopathy hereditary spherocytosis diagnosed simultaneously in 2 individuals in a family. PATIENT: A 66-year-old man with normal pressure glaucoma and hereditary spherocytosis. RESULTS: This patient presented with a branch retinal vein occlusion, and normal tension glaucoma that was incidentally detected. Further history revealed that the patient's maternal grandmother also had hereditary spherocytosis and glaucoma. CONCLUSIONS: We hypothesize that glaucoma and hereditary spherocytosis may be associated. Hereditary spherocytosis may be a potential risk factor for glaucoma by causing impaired blood supply to the optic nerve.