Binocular vision in congenital glaucoma

We have studied binocular vision in a group of 189 patients suffering from congenital glaucoma, before and after treatment, as well as the elements upon which vision depends. Therapeutic modalities, including occlusion are discussed. We insist on the possibility of recovering binocular vision in congenital glaucoma.     

Algorithm for interpreting the results of frequency doubling perimetry

PURPOSE:To evaluate an algorithm for the identification of glaucomatous visual field defects with the screening mode of frequency doubling technology.METHODS:Screening-mode frequency doubling technology and Swedish interactive threshold algorithm perimetry were performed on 137 of 150 consecutive patients referred to a glaucoma specialist. We created an algorithm for the frequency doubling technology that gave increased importance to both more severe defects and defects closer to fixation. These values were then compared with the results of the Swedish interactive threshold algorithm visual fields evaluated by the glaucoma hemifield test, two masked glaucoma specialists, and a published definition of glaucomatous damage to determine sensitivity and specificity of the frequency doubling technology screening mode for detecting glaucoma.     

Temporal contrast sensitivity loss in primary open-angle glaucoma and glaucoma suspects

The need for more sensitive tests for the early detection of compromised visual function in glaucoma is established by anatomic and psychophysical evidence of damage occurring to optic nerve fibers in eyes with normal visual fields. The results are reported of temporal frequency testing on 51 glaucoma suspects without visual field loss in either eye, 52 glaucoma patients with visual field deficits in the tested eye, and 11 normal subjects. Modulation transfer functions were obtained using a sinusoidally flickering 5 degrees spatially uniform white field viewed with central fixation and plotted at six frequencies from 5-30 Hz. The results showed a frequency-specific sensitivity loss centered at 15 Hz and a nonfrequency-specific mean sensitivity loss, that was greater, on average, in glaucoma patients than in suspects. Sensitivity losses of both kinds were seen in most glaucoma patients, but only in a minority of glaucoma suspects. About 12% of suspects were indistinguishable from the lowest performing one third of these glaucoma patients. A smaller number of suspects appeared to form a second mode in the frequency distribution for temporal sensitivity at 15 and 25 Hz. In patients with glaucoma, age was found to be a significant factor associated with the magnitude of mean sensitivity loss. Age was not a significant factor contributing to sensitivity loss in individual suspect data as measured by regression analysis, but it contributed to a small and consistent sensitivity loss across frequency for group-averaged data in those older than 55 years of age.     

Learning effect for frequency doubling perimetry in patients with glaucoma.

PURPOSE: We studied the results obtained by repeated frequency doubling perimetry in patients with glaucoma and demonstrated a learning effect. METHODS: Prospective observational study. Thirty-three patients who had glaucoma and had never experienced frequency doubling perimetry participated in this study. The patients were examined by frequency doubling perimetry three times within 6 months. Mean deviation, pattern standard deviation, and intraocular pressure at examination were compared among three results. RESULTS: On frequency doubling perimetry, the mean deviation results of the first, second, and third tests were -7.96 dB, -7.29 dB, and -7.36 dB, respectively. The first and second results and the first and third results were significantly different (P = 0.029 and P = 0.049, respectively). No significant differences with regard to pattern standard deviation and intraocular pressure were noted. CONCLUSION: A positive learning effect was found for frequency doubling perimetry in the first and second mean deviation results of patients with glaucoma.     

Trends in glaucoma surgery before and after the introduction of new topical glaucoma pharmacotherapies

OBJECTIVE: Recent advances in pharmacotherapy that have improved the ability to effect sustained reductions in intraocular pressure may delay or obviate the need for surgery for open-angle glaucoma. This analysis explored this possibility by evaluating the frequency of surgeries for open-angle glaucoma in the US Medicare population before and after the 1996 introduction of latanoprost, a topical prostaglandin analogue with potent ocular antihypertensive efficacy and a better safety profile than older topical glaucoma medications. METHODS: Data from the Medicare 5% Standard Analytical File were used to develop national estimates of the frequency of glaucoma surgeries in the US yearly from 1994 through 1999. RESULTS: While the number of US Medicare patients with a diagnosis of glaucoma remained constant from 1994 through 1999, the number of inpatient and outpatient glaucoma surgeries declined with a particularly sharp drop between 1996 and 1997. In 1999 relative to 1994, the number of annual glaucoma surgeries among unique patients with a diagnosis of glaucoma was reduced by 72% for inpatient procedures and 42% for outpatient procedures. CONCLUSIONS: The number of glaucoma surgeries among US Medicare patients markedly decreased from 1994 to 1999, during which time the prevalence of glaucoma remained stable in this population. The decrease in surgeries coincided with the introduction of improved topical pharmacotherapies for the management of glaucoma. Although the ability to infer a causal relationship between introduction of new pharmacotherapy and the decrease in surgeries is limited, the consistency of these data with those of several other studies renders the findings compelling.     

Identification of glaucoma-related visual field abnormality with the screening protocol of frequency doubling technology

Purpose: To evaluate the predictive power of frequency doubling technology to distinguish glaucoma suspects from persons with glaucoma visual field loss.Methods: A consecutive series of 76 subjects referred to a glaucoma service underwent perimetry in one eye with frequency doubling technology in a screening mode and Humphrey 24-2 threshold testing in random order, and had optic disk and clinical nerve fiber layer grading.Results: All subjects performed perimetry with both instruments satisfactorily, with an average test time of 1.8 ± 0.7 minutes per eye for the frequency doubling technology (instrument time). Of 33 eyes classified as abnormal by glaucoma hemifield test, 91% (30/33) were abnormal on frequency doubling technology (two or more abnormal locations of 17), whereas 94% (31/33) of glaucoma suspects with normal Humphrey fields had normal results with frequency doubling technology. Frequency doubling technology results were highly correlated with Humphrey mean deviation by linear regression (r² = .74, P = .047) and with corrected pattern standard deviation probability value. A frequency doubling technology error score for each quadrant of the field was highly correlated with the number of severely abnormal points per quadrant in Humphrey threshold tests (r² = .63, P = .034). There was close agreement between clinical examination of the optic disk and nerve fiber layer and frequency doubling technology results. Three-level quantification of abnormality in frequency doubling technology results did not add to diagnostic accuracy.Conclusion: Frequency doubling technology testing shows promise as a screening method in glaucoma.     

Screening for primary open-angle glaucoma in the developed world: are we there yet?

BACKGROUND: In 1995, the Quebec Agency for Health Services and Technology Assessment (AETMIS) stated that a formal screening program for primary open-angle glaucoma (POAG) could not be recommended for the province of Quebec, owing to "a high degree of uncertainty and because of the high cost such a program would entail." The purpose of this article was to evaluate the possibility of instituting a POAG screening program in light of recent advances in the diagnosis and treatment of glaucoma. METHODS: We reviewed new developments that have occurred since the mid to late 1990s in the field of glaucoma. Changes that could positively influence the feasibility and organization of future glaucoma screening programs were identified. RESULTS: New technologies, including confocal scanning laser ophthalmoscopy (HRT II), optical coherence tomography (Stratus OCT), and scanning laser polarimetry with variable corneal compensation (GDx-VCC), permit early detection of optic nerve and nerve fibre layer structural damage. Together with advanced psychophysical tests (frequency doubling perimetry and short wavelength automated perimetry) for earlier detection of functional damage, they provide an increased understanding of the diagnosis and monitoring of POAG. Elevated intraocular pressure (IOP) remains the most important risk factor for glaucoma. Clinical trials indicate that lowering IOP at different stages of the disease can arrest or decrease its rate of progression. Moreover, it is important to assess pachymetry because IOP measurements are influenced by central corneal thickness. Finally, new treatments, such as prostaglandin analogues or selective laser trabeculoplasty, are safer and may also achieve lower intraocular pressures. INTERPRETATION: Health policy involves the investment of public resources, and cost-effectiveness analyses for POAG screening are heavily weighted by the degree of uncertainty that glaucoma screening can be effectively and reliably achieved. The many new developments and advancements outlined herein, combined with the possible increasing prevalence of POAG, necessitate the re-evaluation of screening for primary open-angle glaucoma.     

原发性闭角型青光眼的发病机制研究新进展

原发性闭角型青光眼(PACG)是临床上最常见的一种青光眼类型,全球发病率高且致盲性大,具有进行性不可逆发展的特点。PACG的发病机制复杂多样,不仅与眼部解剖结构的异常有关,如前房结构出现角膜小、短眼轴和浅前房等特征,近年研究还发现晶状体、虹膜、睫状体及脉络膜异常均与PACG的发病有关。另外PACG的发生与遗传因素和心理应激因素亦有较紧密的关系,本文结合文献报道较为全面地从解剖特征、遗传因素、心理应激三个方面对PACG的发病机制做了简要论述,希望籍此为青光眼的早期诊断和治疗提供有益的理论支撑。     

Central retinal artery occlusion (reversible in sickle trait with glaucoma.

We report a case of central retinal artery occlusion in an 18-year-old black woman with sickle-trait haemoglobinopathy and acute glaucoma after hyphaema. The central retinal artery occlusion occurred immediately after treatment of the glaucoma with osmotic agents, raising the possibility that they played a precipitating role. We suggest that osmotic agents be used with extreme caution in sickle patients with glaucoma. The occlusion was treated by anterior chamber paracentesis with eventual return of good vision. The reversibility of retinal and optic nerve function after total ischaemia is discussed.     

Awareness of eye diseases and risk factors: identifying needs for health education and promotion in Canada

BACKGROUND: Little is known about the level of general public knowledge in Canada regarding the risk factors, prevention, and treatment of major blinding eye diseases. METHODS: The study was a cross-sectional survey using self-administered questionnaires of patients presenting to 33 family practitioners' offices in British Columbia. We asked patients' opinions on the "value" of preventing blindness; the possibility of preventing cataract, glaucoma, and macular degeneration; the possibility of treating these conditions; and their knowledge of risk factors. RESULTS: A total of 882 adults completed the questionnaires. Preventing vision loss was reported as one of 2 top health priorities in 28% of the questionnaires, more commonly by those with higher education and non-European ancestry. Overall, 69.2% reported familiarity with cataract as a cause of vision loss, 41.2% with glaucoma, and 20.2% with macular degeneration. Of these, 97.5% recognized the possibility of treatment for cataract, 91.5% for glaucoma, and 77.0% for macular degeneration, yet few respondents knew risk factors (amenable to intervention) for specific eye diseases. Men and younger respondents were more likely to report not knowing risk factors. Chinese-Canadians were least familiar with the association between smoking and cataract. Family history, probably the most important factor to help diagnose glaucoma, was recognized by only 23% of respondents. INTERPRETATION: Although loss of vision was reported as a major medical concern, there is little understanding of the risk factors for different eye diseases. The association of non-European ancestry and low educational attainment with poor knowledge of eye diseases suggests that innovative education programmes in primary and secondary schools and in non-English languages are needed to improve knowledge, attitudes, and practices.     

经巩膜睫状体光凝作为青光眼首选手术方式的探讨及展望

睫状体光凝是难治性青光眼的主要治疗手段之一,其降眼压速度快、效果佳,但由于存在眼球萎缩和视力下降的风险,使其临床应用受到限制.经巩膜睫状体光凝的术后效果及并发症的发生主要与激光能量、点数、范围等操作参数以及患者眼部色素水平有关.其降眼压作用不依赖于房角开放状况,对操作技术要求相对较低.随着技术的进步和光凝参数的优化,睫状体光凝的安全性和有效性较前大大提高.同时由于其非侵入的特性,避免了许多青光眼滤过手术相关的严重并发症.结合地区经济发展水平、医疗资源配置情况、患者意愿和随访依从性等因素,近年来有研究者尝试将经巩膜睫状体光凝用于视力尚好的原发性开角型青光眼患者和药物控制不佳的慢性闭角型青光眼,并作为新生血管性青光眼的首选手术治疗方案,取得了较好效果,为青光眼的治疗提供了新的思路.本文对经巩膜睫状体光凝的安全性、有效性及其影响因素进行了综述,同时对其作为青光眼患者首选手术治疗方案的可能性和可行性作以分析、探讨和展望.     

Is Genetic Risk for Sleep Apnea Causally Linked With Glaucoma Susceptibility?

PurposeObservational studies have suggested that individuals with pre-existing sleep apnea (SA) have up to double the risk of developing glaucoma than individuals without SA. Understanding risk factors for glaucoma is important to assist with well-structured screening, early intervention, and efficient allocation of specialist consultation. The objective of this study is therefore to use genetic data to determine whether SA is a causal risk factor for glaucoma.MethodsTwo-sample Mendelian randomization (MR) analyses were performed to assess the association between genetically predicted SA and glaucoma susceptibility using genome-wide association study (GWAS) of 25,062 SA cases, 313,372 controls derived from 23andMe and summary data from a glaucoma GWAS meta-analysis (20,582 cases, 119,318 controls), including individuals of European descent, mainly from the UK Biobank.ResultsInverse variance weighted regression of genetic susceptibility for SA on risk of glaucoma revealed no strong evidence for an association between SA and glaucoma (OR = 0.95, 95% confidence intervals = 0.84–1.07), results were consistent across all MR predictors.ConclusionsWe found little genetic evidence supporting a causal association between SA and glaucoma. Our results refute the possibility of a large effect (glaucoma OR > 1.5 per doubling of odds on SA) between SA and glaucoma.     

Postradiation secondary glaucoma and prevention measures]

The authors have examined the possibility of preventing the development of secondary glaucoma after eye irradiation with a narrow medicinal proton beam. Twenty-eight patients with cilio-choroidal melanoma were involved in the study, 7 male and 21 female ones, aged 48.4 on an average. The authors' findings evidence that postradiation changes in the anterior segment of the eye, resulting from radiation iridocyclitis, are mainly responsible for the development of secondary glaucoma. Preliminary laser-effected formation of iridal coloboma is conducive to a normal flow in the anterior chamber at the expense of an additional pupil functioning and thus helps reduce the possibility of secondary glaucoma development by 1.6 times (or by 38.5%).     

The Groningen Longitudinal Glaucoma Study. I. Baseline sensitivity and specificity of the frequency doubling perimeter and the GDx nerve fibre analyser

PURPOSE: To describe the baseline data of a large cohort of patients included for follow-up with perimetry using the frequency doubling technique (FDT) and with quantification of the retinal nerve fibre layer as assessed by GDx, and to calculate the sensitivity and specificity of both devices from these baseline data. METHODS: Regular visitors to our glaucoma service were included. All subjects were followed for at least 4 years with FDT in full-threshold mode, GDx and conventional perimetry. Patients were classified as having either glaucoma or suspect glaucoma, according to baseline perimetry results. In addition, a group of healthy subjects was recruited outside the hospital. RESULTS: A total of 452 glaucoma patients, 423 glaucoma suspects and 237 healthy subjects were incorporated into the analyses. Sensitivities for both FDT and GDx were fixed at 0.90. For the group as a whole, the specificity was 0.81 for FDT, using number of depressed test-points p < 0.01 in the total deviation probability plot with a cut-off point > 1, and 0.78 for GDx, using the Number, with a cut-off point > 29. The area under the receiver operating characteristic (ROC) curve was 0.92 for FDT and 0.94 for GDx. Of the subjects with suspect glaucoma, 75% showed normal FDT test results and 52% showed normal GDx results. Unlike FDT, GDx failed to detect some moderate/severe glaucoma cases. CONCLUSIONS: The performances of FDT and GDx are approximately equivalent in terms of sensitivity, specificity and area under the ROC curve. In glaucoma suspects, GDx in particular yielded a rather high percentage of positive test results. The majority of these positive test results are presumably false-positive results rather than results indicating preperimetric glaucoma.     

A glaucoma survey in South India

Conclusions In India, villagers will not seek medical advice, as long as they can see on one eye. The frequency of glaucoma in South India was similar to that to be expected in Europe or USA. It was not possible to perform a population survey. We had to concentrate on that part of the population who attends eye camps or an eye hospital, a pre-selected and motivated group of the entire population with most probably more glaucoma cases than with those not motivated to seek medical advice. We could show that our diagnostic methods did not result in over-diagnosing mere tonometric glaucomas. Every fifth eye in our glaucoma patients was blind from glaucoma, which demonstrates that we had a very high percentage of late stage of the diseases amongst our patients, although it was not possible to include perimetry in the diagnostic procedures.Glaucoma screening in villagers without offering other medical services was not successful in this part of the world, but glaucoma screening must be included in the work of eye camps and outpatient departments of eye hospitals. Once a diagnosis of glaucoma is established, surgery should be offered to the patient. Long-term treatment with drugs will not be appreciated but soon be refused or forgotten by the illiterate patients.     

Surgical management of glaucoma: a review

This review will briefly describe the history of surgical glaucoma treatment and concentrate on the current surgical strategies for managing glaucoma. A discussion of treatments for angle closure, open-angle glaucoma and paediatric glaucoma with an emphasis on drainage surgery are included. The role of cataract surgery is also briefly described. Drainage surgery evolved from peripheral iridectomy and sclerotomy with an increasing understanding of aqueous flow within the eye and the production of a functioning bleb. The current mainstays include trabeculectomy, glaucoma drainage devices as well as goniotomy and trabeculotomy, which have all been in existence for more than 40 years. Their various advantages as well as methods used to minimize their disadvantages, including the antimitotics and case selection are discussed. We finish by discussing the preliminary results of some newer forms of drainage surgery illustrating the energetic search for methods to minimize the problems of hypotony and bleb failure.     

A clinical evaluation of uveitis-associated secondary glaucoma

PURPOSE: To investigate the clinical features of secondary glaucoma associated with uveitis. SUBJECTS AND METHODS: The subjects of the study were 1,604 eyes of 1,099 patients with uveitis at Miyata Eye Hospital, Miyakonojo, Miyazaki, between October 1974 and January 2000. The intraocular pressure (IOP) and clinical data were analyzed retrospectively. Secondary glaucoma was defined as being an IOP higher than 21 mmHg and needing treatment with medication to control the high IOP. RESULTS: Secondary glaucoma was found in 293 eyes (18.3%) of 217 patients (19.7%) among the uveitis patients. The clinical entity with the highest frequency of secondary glaucoma was Posner-Schlossman syndrome in 100%, followed by sarcoidosis in 34.1%, herpetic anterior uveitis in 30.4%, Beh?et's disease in 20.8%, HLA-B 27 related acute anterior uveitis in 20.0%, Vogt-Koyanagi-Harada' disease in 16.4%, and HTLV-1 uveitis in 16.2%. Among the 293 eyes with secondary glaucoma, the majority (72%) had active anterior uveitis at the time of high IOP. Only 7.5% of secondary glaucoma eyes had peripheral anterior synechia wider than 180 degrees of trabecular meshwork. Steroid glaucoma was found only in 8.9% of the secondary glaucoma eyes. Surgical therapy mainly with trabeculectomy with anti-metabolites was performed in 38 eyes and the postsurgical IOP was controlled to 20 mmHg or lower in 36 eyes. Despite the medical and surgical therapy for secondary glaucoma, defect of the visual field was found in 38% of the secondary glaucoma eyes. CONCLUSIONS: The frequency of secondary glaucoma in 1,604 eyes with uveitis was 18.3%, and the frequency of secondary glaucoma differed depending upon the clinical entity of uveitis. The evaluation and the management of IOP are very important in treatment patients with uveitis, in addition to the management of intraocular inflammation.     

Current concepts in the pathogenesis and management of exfoliation syndrome and exfoliative glaucoma

Exfoliative glaucoma is a common, sight-threatening disease that develops as a consequence of exfoliation syndrome. There are important differences in the clinical appearance, course, and prognosis of exfoliative glaucoma versus primary open-angle glaucoma. At the clinical, biochemical, and cellular levels, exfoliative glaucoma is a distinct entity, with an intriguing mechanism of development and numerous systemic manifestations that require further elucidation. The subtlety of clinical signs results in the diagnosis of exfoliative glaucoma often being overlooked and resulting in less-than-ideal management. We provide an overview of recent studies investigating the medical, laser, and surgical therapy of exfoliative glaucoma, with a focus on innovative approaches that may slow the progression of, or even prevent, the development of exfoliation syndrome and exfoliative glaucoma.     

Surgical management of patients with combined glaucoma and corneal transplant surgery

The reasons for having combined glaucoma and corneal transplant surgery are myriad. Patients with corneal transplants have a high frequency of developing secondary glaucoma. Patients with preexisting glaucoma have even higher risk for developing glaucoma refractory to medical management after penetrating keratoplasty. The indication for corneal transplant affects the risk for developing postkeratoplasty glaucoma. The surgical treatment options for treating glaucoma include laser trabeculoplasty, cycloablation, trabeculectomy, and glaucoma drainage implants. In addition, the sequencing of glaucoma surgery relative to penetrating keratoplasty affects the outcome. Newer corneal transplant techniques may have a lower risk for developing secondary glaucoma.