Oftalmopatías: situación epidemiológica de egresos hospitalarios en el Hospital Regional Guillermo Grant Benavente entre los años 2018 y 2021 / Ophthalmopathy: epidemiological situation of hospital discharges at the Guillermo Grant Benavente Regional Hospital between 2018 and 2021

Introducción: La salud visual es de vital importancia para el individuo, habiendo una mayor incidencia de oftalmopatías sobre los 50 años. Pese a su impacto sanitario, Chile carece de estudios epidemiológicos suficientes. La gran variabilidad de sus presentaciones hace importante conocer cuales ameritan el tratamiento intrahospitalario. Objetivo: Describir las principales causas de egresos hospitalarios por enfermedades del ojo y sus anexos en el Hospital Regional Guillermo Grant Benavente entre los años 2018 y 2021. Materiales y métodos: Estudio ecológico que analizó 1764 egresos hospitalarios por enfermedades del ojo y sus anexos del Hospital Guillermo Grant Benavente entre los años 2018 y 2021. Los datos corresponden al Departamento de Estadísticas e Información en Salud (DEIS). Resultados: Las patologías más prevalentes fueron: Trastornos De La Coroides Y De La Retina (33%) (TCR) Trastornos Del Cristalino (14,7%), Trastornos De La Esclerótica, Córnea, Iris Y Cuerpo Ciliar (10,2). Trastornos Del Párpado, Aparato Lagrimal Y Órbita (12,7%) (TPAO) Esta última con diferencias estadísticamente significativas para el sexo. Conclusión: Se ve una disminución de la atención hospitalaria desde el año 2020 debido a la pandemia del virus SARS-COV-2. No hay diferencias por sexo, excepto para la TPAO, similar a lo visto en la literatura. La acumulación de oftalmopatías en el rango de población adulta y adulta mayor, refleja un envejecimiento poblacional. Se reconoce además a los TCR como la patología con mayor incidencia. El estudio contribuye a la epidemiologia local, aportando a la falta de conocimientos actualizados, describiendo los diagnósticos más frecuentes de la especialidad.

Introduction: Eye care is vital for the individual, with a higher incidence of ophthalmopathy over 50 years. Despite its health impact, Chile lacks sufficient epidemiological studies. The great variability of their presentations makes it important to know which ones merit in-hospital treatment. Objective: To describe the main causes of hospital discharges for eye diseases and its adnexa at the Guillermo Grant Benavente Regional Hospital between 2018 and 2021. Material and methods: An ecological descriptive study that analyzed 1,764 hospital discharges for eye diseases and its adnexa from the Hospital Guillermo Grant Benavente between the years 2018 and 2021. The data corresponds to the Department of Statistics and Health Information (DEIS). Results: The most prevalent pathologies were: Disorders of the Choroid and Retina (33%) (TCR), Disorders of the Lens (14.7%), Disorders of the Sclera, Cornea, Iris, and Ciliary Body (10.2). Disorders of the Eyelid, Lacrimal Apparatus and Orbit (12.7%) (TPAO) The latter with statistically significant differences for sex. Conclusion: A decrease in hospital care is seen since 2020 due to the SARS-COV-2 virus pandemic. There are no differences by sex, except for PPAO, similar to what has been seen in the literature. The accumulation of ophthalmopathy in the range of the adult population and older adults, reflects an aging population. TCR is also recognized as the pathology with the highest incidence. The study contributes to the local epidemiology and the lack of updated knowledge, describing the most frequent diagnoses of the specialty.

Population-based Incidence of Intraocular Lens Exchange in Olmsted County, Minnesota.

PURPOSE: To determine the population-based incidence of pseudophakic intraocular lens exchange in Olmsted County, Minnesota. DESIGN: Retrospective review of a population-based cohort. METHODS: Patients undergoing pseudophakic intraocular lens exchange in Olmsted County, Minnesota, between January 1, 1986 and December 31, 2016 were identified from the Rochester Epidemiology Project medical record linkage system. Indications and outcomes were determined, and the incidence rate was calculated as cases per 1 000 000 person-years. Poisson regression analysis was used to assess changes in incidence over time, and the cumulative probability of needing a lens exchange was estimated by Kaplan-Meier analysis. RESULTS: Eighty cases of intraocular lens exchange were identified, yielding an overall age- and sex-adjusted incidence rate of 28.4 per million (confidence interval [CI], 22.1-34.7), which increased over the study period (P = .04). The 30-year cumulative probability of intraocular lens exchange among patients undergoing cataract surgery was 1.5% (CI, 0.6%-2.4%), increasing at a relatively constant rate. Dislocated lenses accounted for 72.5% of lens exchanges. Unplanned refractive outcome of primary cataract surgery and uveitis-glaucoma-hyphema syndrome from squared-edged haptics emerged as newer indications for intraocular lens exchange. CONCLUSIONS: The population-based incidence of pseudophakic intraocular lens exchange has increased over the last 30 years, and can be explained by the increase in incidence rate of cataract surgery over the same period. Surgeons should be aware of emerging indications of intraocular lens exchange, which reflect changes in lens design and increasing expectations of refractive outcomes.

The Incidence and Risk Factors of Lens-iris Diaphragm Retropulsion Syndrome during Phacoemulsification.

PURPOSE: In the present study, the incidence and risk factors of lens-iris diaphragm retropulsion syndrome (LIDRS) were evaluated. METHODS: Patients who underwent cataract surgery using phacoemulsification between June 2014 and December 2014 were included in the study. The preoperative ocular biometric and intraoperative surgical parameters were examined. The incidence of LIDRS and various risk factors were analyzed using an independent t-test, Pearson's chi-square test, and univariable and multivariable logistic regression analyses. RESULTS: Among 124 eyes of 124 patients, 100 (80.6%) had no LIDRS and 24 (19.4%) had LIDRS. LIDRS occurred in 13 of 31 vitrectomized eyes (41.9%) and 11 of 93 non-vitrectomized eyes (11.8%). Based on univariable analysis, age (odds ratio [OR], 0.920; p = 0.001), vitrectomized eye (OR, 5.038; p = 0.001), spherical equivalent (OR, 0.778; p < 0.001), axial length (OR, 1.716; p < 0.001), anterior chamber depth (OR, 3.328; p = 0.037), and 3.0 mm vs. 2.2 mm incision size (OR, 4.964; p = 0.001) were statistically significant risk factors associated with the development of LIDRS. Conditional multivariable logistic regression showed that vitrectomized eye (OR, 3.865; 95% confidence interval [CI], 1.201 to 12.436; p = 0.023), long axial length (OR, 1.709; 95% CI, 1.264 to 2.310; p = 0.001), and 3.0 vs. 2.2 mm incision size (OR, 3.571; 95% CI, 1.120 to 11.393; p = 0.031) were significant independent risk factors associated with LIDRS. CONCLUSIONS: LIDRS is a relatively common occurrence and was found to be associated with vitrectomized eye, long axial length, and larger incision size. Evaluating risk factors prior to cataract surgery can help reduce associated morbidity.

[Visual impairment and blindness in children in a Malawian school for the blind]. / Sehbehinderung und Blindheit bei Kindern in einer malawischen Blindenschule.

PURPOSE: The aim of this study was to determine the anatomic sites of severe visual impairment and blindness in children in an integrated school for the blind in Malawi, and to compare the results with those of previous Malawian blind school studies. METHODS: Children attending an integrated school for the blind in Malawi were examined in September 2011 using the standard WHO/PBL eye examination record for children with blindness and low vision. Visual acuity [VA] of the better eye was classified using the standardised WHO reporting form. RESULTS: Fifty-five pupils aged 6 to 19 years were examined, 39 (71 %) males, and 16 (29 %) females. Thirty eight (69%) were blind [BL], 8 (15 %) were severely visually impaired [SVI], 8 (15 %) visually impaired [VI], and 1 (1.8 %) was not visually impaired [NVI]. The major anatomic sites of visual loss were optic nerve (16 %) and retina (16 %), followed by lens/cataract (15 %), cornea (11 %) and lesions of the whole globe (11 %), uveal pathologies (6 %) and cortical blindness (2 %). The exact aetiology of VI or BL could not be determined in most children. Albinism accounted for 13 % (7/55) of the visual impairments. 24 % of the cases were considered to be potentially avoidable: refractive amblyopia among pseudophakic patients and corneal scaring. CONCLUSIONS: Optic atrophy, retinal diseases (mostly albinism) and cataracts were the major causes of severe visual impairment and blindness in children in an integrated school for the blind in Malawi. Corneal scarring was now the fourth cause of visual impairment, compared to being the commonest cause 35 years ago. Congenital cataract and its postoperative outcome were the commonest remedial causes of visual impairment.

Regulating exposure of the lens of the eye to ionising radiations.

The International Commission on Radiological Protection (ICRP) has reviewed recent epidemiological evidence suggesting that, for the lens of the eye, the threshold in absorbed dose for the induction of deleterious health effects is about 0.5 Gy. On this basis, the Commission recommends that for occupational exposure in planned exposure situations, the equivalent dose limit for the lens of the eye should be 20 mSv in a year, averaged over defined periods of 5 yr, with exposure not exceeding 50 mSv in any single year. This paper summarises the data that have been taken into account by the ICRP and critically examines whether the proposed downward revision of the dose limit is justified. Overall, it is concluded that the accumulating radiobiological and epidemiological evidence makes it more appropriate to treat cataract induction as a stochastic rather than a deterministic effect. Within this framework, it is illogical to have the same dose limit for the lens of the eye as for the whole body irradiated uniformly. This could be addressed either by removing the special dose limit for the lens of the eye, assigning it an appropriate tissue weighting factor and including it in the computation of the effective dose, or through a composite approach involving the use of a tissue weighting factor for effective dose computations together with a special limit on the equivalent dose to the lens of the eye to ensure that no individual was subject to an unacceptably high risk of induction of clinically significant cataracts.

Eye lens radiation exposure and repeated head CT scans: A problem to keep in mind.

OBJECTIVES: The deterministic character of radiation-induced cataract is being called into question, raising the possibility of a risk in patients, especially children, exposed to ionizing radiation in case of repeated head CT-scans. This study aims to estimate the eye lens doses of a pediatric population exposed to repeated head CTs and to assess the feasibility of an epidemiological study. METHODS: Children treated for a cholesteatoma, who had had at least one CT-scan of the middle ear before their tenth birthday, were included. Radiation exposure has been assessed from medical records and telephone interviews. RESULTS: Out of the 39 subjects contacted, 32 accepted to participate. A total of 76 CT-scans were retrieved from medical records. At the time of the interview (mean age: 16 years), the mean number of CT per child was 3. Cumulative mean effective and eye lens doses were 1.7mSv and 168mGy, respectively. CONCLUSION: A relatively high lens radiation dose was observed in children exposed to repeated CT-scans. Due to that exposure and despite the difficulties met when trying to reach patients' families, a large scale epidemiological study should be performed in order to assess the risk of radiation-induced cataracts associated with repeated head CT.

Decreasing rate of capsule complications in cataract surgery: eight-year study of incidence, risk factors, and data validity by the Swedish National Cataract Register.

PURPOSE: To define the incidence of capsule complication and its risk factors in Sweden over an 8-year period. SETTING: Fifty-two ophthalmic surgery units in Sweden. DESIGN: Database study. METHODS: Data were collected prospectively in the Swedish National Cataract Register (NCR) from 2002 through 2009. The NCR contains 97.3% of the total number of cataract extractions in Sweden over the 8-year study period. One mandatory variable in the register is capsule complications during surgery. As a means to validate the accuracy of register data on capsule complications, a randomly selected sample of 2400 registrations was compared with corresponding medical records. RESULTS: The analyses were based on 602,553 cataract extractions reported to the NCR. A capsule complication was reported in 12,574 cataract extractions, corresponding to a frequency of 2.09%. The incidence of this complication consistently decreased each year from 2002 to 2006, after which it stabilized. Poor corrected distance visual acuity in the surgical eye (≤ 0.1), the occurrence of glaucoma, diabetic retinopathy, and age were among the parameters significantly related to a capsule complication. Some of these parameters also decreased over time. However, even after adjusting for this, there was an obvious decrease in capsule complications over time. The validity test showed a certain underreporting of capsule complications to the registry, but it was not significant and did not change over time. CONCLUSION: The incidence of capsule complications decreased over time. This may be partly the result of fewer risk factors and of better surgical quality. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

The frequency of pseudoexfoliation syndrome in the middle Black Sea region of Turkey.

PURPOSE: To assess the frequency of pseudoexfoliation syndrome (PEX) and evaluate its association with specific ocular diseases in patients attending the Department of Ophthalmology at Gaziosmanpasa University Hospital. METHODS: A prospective study was conducted at the Gaziosmanpasa University Hospital between December 2007 and December 2008. A total of 831 subjects aged 45 or above attending the general ophthalmic clinics were recruited for this study. Each patient underwent complete ophthalmic assessment, including ocular history, visual acuity testing, slit-lamp examination, applanation tonometry, gonioscopy, and fundus examination. RESULTS: Of the 831 subjects, 12.2% had PEX. Pseudoexfoliation was bilateral in 74.2% of cases, significantly associated with cataract, glaucoma, age-related macular degeneration (AMD), and phacodenesis. Of the patients with PEX, 43.6% had cataract, 6.9% had glaucoma, 7.9% had AMD, and 0.9% had phacodenesis. In addition, 9.8% had cataract + glaucoma, 13.7% had cataract + phacodenesis, and 17.8% had all of them. The prevalence of PEX had a tendency to increase with age but had no sex predilection. CONCLUSIONS: The study findings enhance our knowledge of PEX in Anatolia, particularly in the Middle Black Sea region.

[Ocular findings in Alport syndrome: 32 case studies]. / Atteinte oculaire au cours du syndrome d'Alport. A propos de 32 cas.

BACKGROUND: Alport syndrome is an inherited disease resulting in kidney failure, hearing loss, and ocular abnormalities. The purpose of this study was to describe the incidence and type of ocular abnormalities and to determine inheritance of this syndrome in our population. PATIENTS AND METHODS: A total of 32 patients, from ten different families in South Tunisia, underwent a complete ocular examination. Inheritance was determined using pedigrees and genotyping. RESULTS: The best corrected visual acuity was 7.6/10. Biomicroscopy showed polymorphous dystrophy in 3%, anterior lenticonus in 28%, lens opacities in 3%, cataract in 19%, and retinal flecks in 37%. The genetic survey found five families with X-linked Alport syndrome, four families with recessive autosomal disease, and one family with dominant autosomal disease. DISCUSSION: Ocular abnormalities have been reported in 9%-82% of Alport syndrome patients. They are rare in childhood and increase in frequency and severity with age. The types of ocular defects described mostly involve the lens, the retina and more rarely the cornea. The most common changes are anterior lenticonus and perimacular retinal flecks. In approximately 85%, Alport syndrome is X-linked. In the remaining 15%, the transmission is autosomal recessive and exceptionally autosomal dominant. CONCLUSION: Ocular examination is a precious help for Alport syndrome diagnosis. It can also determine the prognosis of nephropathy.

Single-piece acrylic intraocular lens implantation in children.

PURPOSE: To assess the short-term outcomes of single-piece acrylic intraocular lens (IOL) implantation in children by determining the incidence of postoperative visual axis opacification and the need for a second procedure to clear the axis, cell deposits on the IOL optic, posterior synechias, and IOL decentration. SETTING: Miles Center for Pediatric Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: This retrospective case review comprised 43 consecutive implantations (33 patients) of a single-piece hydrophobic acrylic IOL (AcrySof SA30AL or SA60AT, Alcon). An analysis of 42 eyes with posterior capsulectomy and vitrectomy was performed. Eyes with traumatic cataract and secondary IOLs were excluded. RESULTS: Single-piece acrylic IOLs were implanted in 42 eyes. The mean age was 33.5 months +/- 28.9 (SD) (range 0.5 to 110 months) and the mean follow-up, 12.0 +/- 8.2 months (range 1.0 to 27.5 months). Postoperative opacification of the visual axis occurred in 7 eyes (16.7%). Secondary surgical procedures were required in 5 eyes (11.9%). Lens deposits were observed in 8 eyes (19.0%) and synechias, in 5 eyes (11.9%). All IOLs were well centered postoperatively. CONCLUSION: The short-term data suggest implantation of the AcrySof single-piece hydrophobic acrylic IOL is safe in the pediatric eye.

Phacoemulsification without intraocular lens implantation in patients with high myopia: long-term results.

PURPOSE: To estimate the cumulative incidence of postoperative retinal detachment (RD), rhegmatogenous retinal lesions requiring argon laser treatments, anterior (ACO) and posterior (PCO) capsule opacification, and neodymium:YAG (Nd:YAG) laser capsulotomy in patients with high myopia who had phacoemulsification without intraocular lens (IOL) implantation. SETTING: Department of Ophthalmology and Neurosurgery, University of Siena, Siena, Italy. METHODS: Seventy-three eyes of 57 patients with high myopia who had phacoemulsification without IOL implantation from 1993 to 1996 were retrospectively reviewed. The mean postoperative follow-up was 62.3 months and the mean axial length, 30.22 mm (range 29.10 to 33.70 mm). The incidence of RD and preoperative and postoperative prophylactic argon laser photocoagulation for rhegmatogenous retinal lesions were assessed. Between 1997 and 2000, ACO was evaluated subjectively and PCO was evaluated using the EPCO photographic image-analysis system. The incidence of Nd:YAG laser capsulotomy was noted. RESULTS: Argon laser photocoagulation was performed in 8 eyes (10.9%) preoperatively and 3 eyes (4.1%) postoperatively. One RD (1.3%) was observed 26 months after surgery; no preoperative or postoperative prophylactic argon laser photocoagulation or Nd:YAG laser capsulotomy was performed in this eye. At 1 year, 49 eyes (67.1%) had mild ACO and 24 (32.8%) had anterior capsule fibrosis. The data did not change during subsequent follow-up visits. At 6 years, the mean PCO grade was 1.109 (range 0.972 to 2.931); an Nd:YAG laser capsulotomy was performed in 12 eyes (16.4%). CONCLUSIONS: Compared with other studies that evaluated the outcomes of highly myopic patients who had cataract surgery with posterior chamber IOL implantation, our patients, who did not have IOL implantation, had a lower incidence of postoperative rhegmatogenous retinal lesions requiring argon laser treatments and a similar incidence of postoperative RD and visually significant PCO.

Prevalence of pigmented lens striae in a black population: a potential indicator of age-related pigment dispersal in the anterior segment.

PURPOSE: To determine the prevalence of pigmented striae of the anterior lens capsule, with or without associated glaucoma, in a black primary eye care population. METHODS: Over a 16-month period, five practitioners searched for pigmented lens striae (PLS) among consecutive patients who underwent pupillary dilation during routine eye care provided within the primary care service of an urban eye clinic in Chicago, Illinois. RESULTS: Meeting the inclusion criteria were 1608 blacks (mean age +/- SD, 40.9 +/- 23.7 years; range, 5 to 100; 1056 females, 552 males). Among the group, 29 (1.8%) subjects had PLS (mean age, 66.5 +/- 11.3 years; range, 33 to 88; 25 females, 4 males). PLS were bilateral 89% of the time. Sixteen of the 29 (55%) blacks had central corneal endothelial pigment dusting (14 bilateral), frequently creating a well-formed Krukenberg's spindle. Trabecular pigmentation varied among the PLS subjects from mild to heavy. Using multiple logistic regression, age (in years) (odds ratio, 1.05; 95% confidence interval, 1.02 to 1.07; p = 0.0003), female gender (odds ratio, 4.46; 95% confidence interval; 1.03 to 19.19; p = 0.045), and hyperopic refractive error (in diopters) (odds ratio, 1.35; 95% confidence interval; 1.09 to 1.67; p = 0.006) were significant predictors of PLS. CONCLUSIONS: PLS were present in about 1.8% (2.4% females, 0.7% males) of our black population, and they were frequently associated with other signs of intraocular pigment dispersion. Age, female gender, and refractive error were significant predictors for PLS. This is new information that is helpful for understanding a clinical sign that may be an indicator of age-related pigment dispersal within the anterior segment.

Results of ophthalmologic screening examinations of German Pinschers in Finland--a retrospective study.

OBJECTIVE: To retrospectively review ophthalmologic findings in German Pinschers in Finland. ANIMALS STUDIED: One hundred and twenty-two German Pinschers that had ophthalmologic examination performed according to the Finnish Kennel Club's Eye Scheme before June 15, 1999. PROCEDURES: A total of 154 eye examination reports of 122 dogs were analysed and all described findings were reported. RESULTS: Persistent hyperplastic tunica vasculosa lentis (PHTVL) was diagnosed in 8.4% of all cases, and hereditary cataract (HC) in 6.5%. Even higher numbers of similar changes were reported by ophthalmologists; some of the dogs, however, were officially diagnosed as "free of symptoms" of inherited ocular diseases. A relatively high number (4.5%) of dogs had reported changes in Y sutures. A pedigree analysis suggests recessive inheritance for both diseases. Because of missing information about many dogs in the pedigree, an autosomal incomplete inheritance pattern cannot be ruled out in either case. CONCLUSIONS: Both HC and PHTVL are inherited diseases in German Pinschers. Further studies are needed to determine the importance of the changes found in Y sutures. Discrepancies between the official diagnosis and described changes are probably partially due to the lack of familiarity with the published literature concerning this breed. Further studies are needed to ascertain the inheritance pattern for both diseases. So far breeding with affected animals should be avoided.

Intraoperative complications during cataract surgery in the very old.

PURPOSE: To determine if there is a difference in intraoperative complications during cataract surgery in very old patients (> or = 88 years) compared with younger patients (< 88 years). METHODS: The records of 802 consecutive cataract operations were reviewed. Identical techniques of small-incision phacoemulsification were used in all cases. A total of 102 eyes were in patients aged 88 to 98, designated as the "very old." The remaining 700 eyes were in patients under 88, designated as "younger." The incidence of intraoperative complications in the 2 groups was compared. RESULTS: Posterior capsule tears, vitreous loss, and loss of the nucleus were found as complications. Overall, these events occurred in 10% of the very old and in only 3% of those under age 88. Vitreous loss occurred in 7% of the very old and in only 1.6% of those under 88. There was 1 dropped nucleus in the very old. In the younger patients, 90.5% of eyes with complicated surgery achieved 20/40 visual acuity or better, but only 40% of complicated cases in the very old achieved this. Furthermore, 50% of complicated cases in the very old had visual acuity of 20/200 or worse, all directly attributed to surgical difficulties. Fifteen percent of patients in both groups had trabeculectomies with no influence on complications. We noted that 8% of the very old required pupil stretching compared with 2% of those under 88. CONCLUSIONS: This study strongly suggests that very old patients (i.e., those 88 years and older) have a higher incidence of intraoperative complications during cataract surgery than younger patients. Furthermore, such complications may result in severe visual loss. These findings may have significance as the population ages.

Posterior capsule striae.

PURPOSE: To find the incidence, contributing factors, outcomes, and clinical impact of intraoperative posterior capsule striae. SETTING: Iladevi Cataract & IOL Research Centre, Ahmedabad, India. METHODS: In a prospective study, 100 consecutive eyes had phacoemulsification and intraocular lens (IOL) (AcrySof MA30BA) implantation. The presence of striae was noted at the end of the operation, and factors contributing to their development were identified. Follow-up was done at regular intervals, and the clinical impact of striae on patients' vision was evaluated. RESULTS: Striae were observed in 56 eyes (Group 1) but were absent in 44 (Group 2). Mean age in Group 1 was 65.96 years +/- 9.15 (SD) and in Group 2, 59.20 +/- 10.36 years (P = .0012). Mean axial lengths were 23.47 +/- 1.63 and 24.12 +/- 1.49 mm, respectively (P = .0419). Average lens thickness was greater in Group 1 (4.50 +/- 0.43 mm) than in Group 2 (4.13 +/- 0.41 mm) (P = .0001). The sex of patient, capsulorhexis size and centration, grade of cataract hardness, scleral rigidity, and IOL centration were not found to contribute to striae development. The striae disappeared by 5 months postoperatively and did not show a positive Maddox rod phenomenon. CONCLUSION: Intraoperative striae observed in many patients were associated with relatively older age, greater lens thickness, and shorter axial length. The striae eventually disappeared and had no effect on vision.

Association of HLA type with pseudoexfoliation of the lens capsule.

AIMS/BACKGROUND: To identify an HLA association with pseudoexfoliation of the lens capsule to support the hypothesis that there is a genetic predisposition to pseudoexfoliation. A randomised trial would be ideal for establishing a relation but is more costly and time consuming to conduct. Case-control studies provide an alternative method of establishing a relation. METHODS: The study group comprised 128 subjects who presented to a major eye centre with pseudoexfoliation. Data from blood donors representative of the population of Ireland were used to form a control group. RESULTS: An HLA association with pseudoexfoliation is identified for 14 antigens. Eleven antigens (HLA A1, A33, B8, B47, B51, B53, B57, B62, DR3, DR12, and DR13) are significantly more common in the pseudoexfoliation group while three antigens (HLA B12, B17, and DR2) are significantly less common. Four HLA antigens are strongly associated, with odds ratios of over 7.5. CONCLUSION: The strength of this HLA association is supportive evidence for a genetic component to the development of pseudoexfoliation of the lens capsule.

The cumulative frequency distribution curve of the eye pressure.

Knowledge of the probability of having glaucoma at different levels of eye pressure is a prerequisite for estimating at which eye pressure levels preventive pressure-lowering treatment ought to be applied. The glaucoma tolerance may not be the same in all population groups. Calculation of tolerance distribution curves may be performed if the frequency distribution curves of pressure in eyes with and without glaucoma are known. Regression analysis has been performed to compute curves approaching the cumulative frequency distribution of the eye pressure in different subgroups. Results of a population study including subjects greater than or equal to 65 years of age have been used. An equation describing an asymmetric sigmoid curve has been applied in the curve fitting procedure. The derivative of this equation was used to describe the noncumulative frequency distribution curves. The analysis has been performed in subgroups consisting of normal eyes, glaucomatous eyes, eyes with and without pseudo-exfoliation.