Prevalence of glaucoma in the Northern Finland Birth Cohort Eye Study

The Finnish current care guideline for open-angle glaucoma

This article is an English translation of the 4th Finnish Current Care Guideline for diagnostics, treatment and follow-up of primary open-angle glaucoma, normal-tension glaucoma and pseudoexfoliative glaucoma. This guideline is based on systematic literature reviews and expert opinions with Finland's geographical and operational healthcare environment in mind.

The prevalence of glaucoma in a 70-year-old Swedish population in the city area of Gothenburg

PURPOSE

To determine the prevalence of and risk factors for open-angle glaucoma in a population of 70-year-olds in Gothenburg, Sweden and to compare the visual function between the glaucoma population and the non-glaucoma population.

METHODS

Of the entire cohort (n = 1203), 1182 participants responded a questionnaire on self-reported glaucoma and were tested for blood pressure (BP) and diabetes. In all, 560 participants underwent ophthalmic examination including best-corrected visual acuity (BCVA), intraocular pressure (IOP), central corneal thickness (CCT), contrast sensitivity (CS), perimetry and photos of the retina and lens.

RESULTS

Glaucoma prevalence was 4.8% (95% confidence interval, 3.0%-6.6%), of which 56% was previously undiagnosed. The proportion of participants with diastolic BP >90 mmHg was higher in the non-glaucomatous group (8.3%) than the glaucoma group (0%), p < 0.001. A family history of glaucoma was present in a larger proportion of the glaucoma group (39%) than of the non-glaucomatous group (1.1%), p = 0.001. Mean IOP in individuals without glaucoma was 16 mmHg, versus 21 mmHg in participants with glaucoma detected at the examination. IOP was ≤21 mmHg in 67% among participants with previously unknown glaucoma. BCVA was lower in eyes with previously unknown glaucoma than in eyes without glaucoma (p = 0.017) but BCVA in the best eye did not differ. CCT and CS were similar in all cases.

CONCLUSIONS

The prevalence of glaucoma was comparable to that reported previously. A family history of glaucoma and higher IOP were risk factors associated with glaucoma. BCVA in the best eye did not differ significantly between subjects with and without glaucoma.

A Systematic Review of Glaucoma Diagnosis in Prevalence Studies and Quality of Reporting

PRCIS

This systematic review has revealed that variable definitions of glaucoma continue to be used in prevalence studies, despite the introduction of the International Society of Geographic and Epidemiologic Ophthalmology (ISGEO) criteria.

PURPOSE

To systematically review diagnostic criteria and examinations performed in glaucoma prevalence studies over time and determine the quality of reporting. Accurate estimates of glaucoma prevalence are crucial to inform resource allocation. However, diagnosis of glaucoma comprises inherently subjective examinations and the cross-sectional nature of prevalence studies precludes monitoring for progression.

METHODS

A systematic review of PubMed, Embase, Web of Science, and Scopus was performed to examine diagnostic protocols used by glaucoma prevalence studies and evaluate uptake of the ISGEO criteria, introduced in 2002 to standardize glaucoma diagnosis in prevalence studies. Detection bias and compliance with the Strengthening Reporting of Observational Studies in Epidemiology (STROBE) guidelines were evaluated.

RESULTS

Ten thousand five hundred forty-four articles were identified. After deduplication, 5589 articles were screened, yielding 136 articles pertaining to 123 studies. An absence of data in many countries was identified. Ninety-two percent of studies stated diagnostic criteria, and 62% used the ISGEO criteria since their publication. Weaknesses of the ISGEO criteria were identified. Temporal variations in the performance of various examinations were observed, including heterogeneity in angle assessment. Mean STROBE compliance was 82% (range 59-100%); 72 articles had a low risk of detection bias, 4 had a high risk, and 60 had some concerns.

CONCLUSION

Heterogeneous diagnostic definitions persist in glaucoma prevalence studies, despite introduction of the ISGEO criteria. Standardization of criteria remains imperative and the development of new criteria represent a valuable opportunity to achieve this goal. In addition, methods of determining diagnoses are poorly reported, suggesting a need for improvement in study conduct and reporting. Accordingly, we propose the Reporting of quality Of GlaUcoma Epidemiological Studies (ROGUES) Checklist. We have also identified a need for further prevalence studies in regions with limited data and to update Australian angle closure glaucoma prevalence. Design and reporting of future studies can be informed by this review's insights into diagnostic protocols previously used.

A generalizable deep learning regression model for automated glaucoma screening from fundus images

A plethora of classification models for the detection of glaucoma from fundus images have been proposed in recent years. Often trained with data from a single glaucoma clinic, they report impressive performance on internal test sets, but tend to struggle in generalizing to external sets. This performance drop can be attributed to data shifts in glaucoma prevalence, fundus camera, and the definition of glaucoma ground truth. In this study, we confirm that a previously described regression network for glaucoma referral (G-RISK) obtains excellent results in a variety of challenging settings. Thirteen different data sources of labeled fundus images were utilized. The data sources include two large population cohorts (Australian Blue Mountains Eye Study, BMES and German Gutenberg Health Study, GHS) and 11 publicly available datasets (AIROGS, ORIGA, REFUGE1, LAG, ODIR, REFUGE2, GAMMA, RIM-ONEr3, RIM-ONE DL, ACRIMA, PAPILA). To minimize data shifts in input data, a standardized image processing strategy was developed to obtain 30° disc-centered images from the original data. A total of 149,455 images were included for model testing. Area under the receiver operating characteristic curve (AUC) for BMES and GHS population cohorts were at 0.976 [95% CI: 0.967-0.986] and 0.984 [95% CI: 0.980-0.991] on participant level, respectively. At a fixed specificity of 95%, sensitivities were at 87.3% and 90.3%, respectively, surpassing the minimum criteria of 85% sensitivity recommended by Prevent Blindness America. AUC values on the eleven publicly available data sets ranged from 0.854 to 0.988. These results confirm the excellent generalizability of a glaucoma risk regression model trained with homogeneous data from a single tertiary referral center. Further validation using prospective cohort studies is warranted.

Diabetes mellitus and risk of open-angle glaucoma-A population-based follow-up study

PURPOSE

The aim of this study was to investigate the association of diabetes mellitus (DM) and risk of open-angle glaucoma (OAG).

METHODS

This population-based historic cohort consisted of individuals at age ≥ 40 years with DM treatment initiated 2001-2010 and a reference population matched by age, gender and hospital district. Incidence of OAG was compared between individuals with DM and their matched non-diabetic reference pairs. New glaucoma cases were identified from medication reimbursement certificates and hospital billing records. Incidence rate ratios (IRR) were analysed with Poisson regression models adjusted for age, sex, hospital district, socioeconomic status, systemic medications and chronic diseases. We analysed the sensitivity of the results with adapted input variables and performed a competing events analysis.

RESULTS

Of the 244 100 study subjects meeting inclusion criteria, 2721 (1.1%) developed OAG. Follow-up spanned from 2001 to 2017. DM was associated with a modestly reduced incidence of OAG when adjusted for confounding factors (IRR 0.92, CI 0.85-0.99).

CONCLUSIONS

In our longitudinal population-based study, we found a modest decrease in the risk of OAG for individuals with DM.

Antenatal and neonatal factors and morphology of the optic nerve head in the Northern Finland birth cohort

PURPOSE

The optic nerve head (ONH) is a part of the brain that can be evaluated through the transparent medium of the eye. The purpose of this study was to explore the possible correlations among the properties of the optic nerve head, maternal factors during pregnancy and neonatal parameters in a randomized sample of a birth cohort.

METHODS

The Northern Finland 1966 Birth Cohort has been prospectively monitored since their antenatal period. Data on pregnancy and neonatal period were collected during gestation and right after birth in 1966. A randomized sample of 3070 subjects underwent an ophthalmic assessment at the age of 46-48 years. The examination protocol included scanning laser ophthalmoscopy with the Heidelberg Retina Tomograph. The ophthalmological parameters assessed were the disc area and the neuroretinal rim volume of the ONH.

RESULTS

We found that chronic pulmonary disease of the mother (p = 0.007), the number of gestational weeks (p = 0.030) and the mother's highest measured systolic blood pressure (p = 0.035) during pregnancy had a statistically significant effect on the disc area. Smaller disc size was associated with pulmonary disease and early gestation. There was a significant difference in rim volume between genders (p < 0.001). Women had larger neuroretinal rim volumes compared to men.

CONCLUSION

In this population-based study, the vast majority of antenatal and neonatal factors showed no correlation with optic disc area or rim volume. Furthermore, even the factors with statistically significant correlation with ONH morphology had limited predictive value.

A prospective study on effectiveness of elevated intraocular pressure as a criterion for glaucoma referrals by optometric practitioners in Sweden

PURPOSE

To evaluate the outcome of referrals for suspected glaucoma based on elevated intraocular pressure (IOP) made by optometric practitioners in Sweden.

METHODS

This prospective study included 95 individuals referred to the Skåne University Hospital Malmö, Sweden, during 2019, by optometric practitioners, based on elevated IOP. Positive outcome was defined as a diagnosis of glaucoma, or a diagnosis of suspected glaucoma. Referral accuracy was analysed. Positive predictive values (PPV) of different hypothetical IOP and age thresholds were calculated.

RESULTS

In 34% (95% CI: 24-43%) of the referrals, no eye disease was found. Intraocular pressure (IOP) was the only referral criterion in 77% (73/95). The PPV was 35% (95% CI: 25-45%) for all referrals, 27% (95% CI: 16-38%) for IOP-only referrals and 59% (95% CI: 36-82%) for referrals including additional findings. In IOP-only referrals, no definite diagnosis of glaucoma was made in any patients <45 years of age. Applying a theoretical age limit of ≥45 years with a hypothetical IOP limit of ≥25 mmHg in patients 45-69 years and of ≥22 mmHg in patients ≥70 years increased the PPV to 42% (95% CI: 27-57%). IOP-only referrals would have been reduced by 27% without missing any glaucoma cases.

CONCLUSION

The overall predictive value of the referrals was poor. Glaucoma resources would have been used more effectively by increasing the required age for IOP-only referrals to ≥45 years in combination with different IOP thresholds for certain age groups.

Development of Primary Open Angle Glaucoma-Like Features in a Rhesus Macaque Colony From Southern China

Purpose

To describe the ocular phenotype of spontaneous glaucoma in a non-human primate colony.

Methods

In total, 722 Rhesus macaque monkeys aged 10 to 25 years underwent optical coherence tomography (OCT), fundus photography (FP), and intraocular pressure (IOP) measurements. Monkeys with baseline cup-to-disc ratio (CDR) <0.5 were used to establish baseline ocular features. A subset was followed longitudinally for three years and compared to glaucoma suspects on the basis of OCT/FP criteria.

Results

The average IOP under ketamine sedation and average CDR for the entire colony was 13.0 ± 4.3 mm Hg and 0.38 ± 0.07, respectively. The mean baseline conscious IOP of glaucoma suspects (N = 18) versus controls (N = 108) was 16.2 ± 3.5 mm Hg and 13.9 ± 2.3 mm Hg, respectively (P = 0.001). All glaucoma suspects had unremarkable slit lamp examinations and open angles based on anterior segment OCT. Baseline global circumpapillary retinal nerve fiber layer (RNFL) thickness was 91.5 ± 11.0 µM versus 102.7 ± 8.5 µM in suspects and controls, respectively (P < 0.0001). All sectors on the baseline circumpapillary OCT showed a significant reduction in RNFL thickness versus controls (P ≤ 0.0022) except for the temporal sector (P ≥ 0.07). In three-year longitudinal analysis, neither CDR nor OCT parameters changed in controls (N = 40; P ≥ 0.16), whereas significant increase in CDR (P = 0.018) and nominally significant decreases in two OCT sectors (nasal, P = 0.023 and nasal inferior, P = 0.046) were noted in suspects.

Conclusions

Members of a nonhuman primate colony exhibit important ophthalmic features of human primary open-angle glaucoma.

Translational Relevance

Identification of a spontaneous model of glaucoma in nonhuman primates represents an unprecedented opportunity to elucidate the natural history, pathogenesis and effective therapeutic strategies for the disease.

Effectiveness of Elevated Intraocular Pressure as a Criterion for Glaucoma Referral After 6 Years of Follow-Up

Purpose

To evaluate the long-term predictive value of the need to treat patients referred by optometric practitioners, regarding glaucoma, in Malmö, Sweden, using intraocular pressure (IOP) as the primary referral criterion.

Patients and Methods

This retrospective study included 94 of 108 (87%) individuals referred to the Skåne University Hospital in Malmö, Sweden, for elevated IOP during 2012–2013. Data were extracted from patient records by the end of 2019. Positive outcome was defined as glaucoma, treated suspected glaucoma or treated ocular hypertension (OH) at referral or during the follow-up period. Positive predictive values (PPV) were calculated using different hypothetical thresholds for age and IOP-levels. Long-term follow-up was used to evaluate whether the first visit diagnoses would change over time, and if this would affect the effectiveness of the referrals.

Results

Elevated IOP was the only referral criterion in 84% (n=79). In 28 patients (35%) among the IOP-only referrals, no ocular disease was found, and 26 patients (33%) had a positive outcome at the first visit. Median follow-up time was 6.4 years. PPV according to diagnosis after follow-up was 42% (95% CI: 32–54%) for IOP-only referrals. Including thresholds of ≥45 years of age in combination with an IOP of ≥25 mmHg in the referral criteria would have reduced the number of IOP-only referrals by 27% (21 of 79), and increased the PPV to 57% (95% CI: 45–71%) at the last visit. No positive outcome would have been missed, among those that were followed-up after the first visit, when applying these thresholds for referral, over a follow-up period of six years.

Conclusion

Using only elevated IOP as referral criterion showed a poor accuracy for predicting those that require IOP lowering treatment. The long-term follow-up allowed us to verify the applicability of higher hypothetical threshold requirements on age and IOP for glaucoma referrals from optometric practices.

Combined structure-function analysis in glaucoma screening

AIM

To assess the applicability of a structure-function (S-F) analysis combining spectral-domain optical coherence tomography (SD-OCT) and standard automated perimetry (SAP) in glaucoma screening in a middle-aged population.

METHODS

A randomised sample of 3001 Caucasian participants aged 45-49 years of the Northern Finland Birth Cohort Eye Study was examined. We performed an eye examination, including 24-2 SAP, optic nerve head (ONH) and retinal nerve fibre layer (RNFL) photography and SD-OCT of the peripapillary RNFL. The S-F report was generated by Forum Glaucoma Workplace software. OCT, SAP and the S-F analysis were evaluated against clinical glaucoma diagnosis, that is, the positive '2 out of 3' rule based on the clinician's evaluation of ONH and RNFL photographs and visual fields (VFs).

RESULTS

At a specificity of 97.5%, the sensitivity for glaucomatous damage was 26% for abnormal OCT, 35% for SAP and 44% for S-F analysis. Estimated areas under the curve were 0.74, 0.85 and 0.76, and the corresponding positive predictive values were 8 %, 10% and 12%, respectively. By applying a classification tree approach combining OCT, SAP and defect localisation data, a sensitivity of 77% was achieved at 90% specificity. In a localisation analysis of glaucomatous structural and functional defects, the correlation with glaucoma increased significantly if the abnormal VF test points were located on borderline or abnormal OCT zones.

CONCLUSION

SAP performs slightly better than OCT in glaucoma screening of middle-aged population. However, the diagnostic capability can be improved by S-F analysis.

A Simple Subjective Evaluation of Enface OCT Reflectance Images Distinguishes Glaucoma From Healthy Eyes

Purpose

We present a subjective approach to detecting glaucomatous defects in enface images and assess its diagnostic performance. We also test the hypothesis that if reflectivity changes precede thickness changes in glaucoma there should be reduced correlation between the modalities in glaucoma compared to controls.

Methods

Twenty glaucoma participants and 20 age-matched controls underwent high-resolution OCT scans of one eye. 4 µm-thick enface slabs were constructed through the retina. Enface indices were depths of first gap in visible retinal nerve fiber bundles (RNFBs) and last visible bundle, subjectively evaluated in six sectors of a 3.5 mm circle around the optic disc. Retinal nerve fiber layer thickness (RNFLT) along the same circle was extracted at angles corresponding to enface indices. Between-group differences were tested by linear mixed models. Diagnostic performance was measured by partial receiver operating characteristic area (pAUC).

Results

First gap and last visible bundle were closer to the inner limiting membrane in glaucoma eyes (both P < 0.0001). Enface indices showed excellent diagnostic performance (pAUCs 0.63-1.00), similar to RNFLT (pAUCs 0.63-0.95). Correlation between enface and RNFLT parameters was strong in healthy (r = 0.81-0.92) and glaucoma eyes (r = 0.73-0.80).

Conclusions

This simple subjective method reliably identifies glaucomatous defects in enface images with diagnostic performance at least as good as existing thickness indices. Thickness and reflectivity were similarly related in healthy and glaucoma eyes, providing no strong evidence of reflectivity loss preceding thinning. Objective analyses may realize further potential of enface OCT images in glaucoma.

Translational Relevance

Novel enface OCT indices may aid glaucoma diagnosis.

Profile of Glaucoma in the Eastern Region of Saudi Arabia: A Retrospective Study

Background:

Glaucomas remain asymptomatic until severe, indicating that the actual number of affected individuals may be higher than those diagnosed.

Objective:

To study the clinical patterns of glaucoma cases in the Eastern Province of Saudi Arabia.

Patients and Methods:

This retrospective study was conducted at King Fahd Hospital of the University, Al-Khobar, and Dhahran Eye Specialist Hospital, Dhahran, Saudi Arabia. The medical records of all patients with glaucoma who visited these hospitals from January 2015 to December 2018 were critically reviewed. Data regarding patients' demographic characteristic, clinical data and their medical and surgical management techniques were collected and analyzed.

Results:

A total of 999 patients were included, of which 52.9% were males, 94.8% were Saudi, and the mean age was 58.8 years. Bilateral involvement was observed in 82.3% of cases. Primary open-angle glaucoma (POAG) was the most prevalent type of glaucoma (27.7%), followed by secondary glaucomas (26.7%), primary angle-closure glaucoma (PACG) (18.2%), primary congenital glaucoma (2.7%), and juvenile open-angle glaucoma (2.2%), which were the most frequent glaucoma subsets.

Conclusion:

The study population was most affected by POAG, secondary glaucomas and PACG. Knowledge regarding prevalence of glaucoma is important to plan services, allocate resources, and prevent blindness.

Association of Genetic Polymorphisms in Oxidative Stress and Inflammation Pathways with Glaucoma Risk and Phenotype

Oxidative stress and neuroinflammation are involved in the pathogenesis and progression of glaucoma. Our aim was to evaluate the impact of selected single-nucleotide polymorphisms in inflammation and oxidative stress genes on the risk of glaucoma, the patients’ clinical characteristics and the glaucoma phenotype. In total, 307 patients with primary open-angle glaucoma or ocular hypertension were enrolled. The control group included 339 healthy Slovenian blood donors. DNA was isolated from peripheral blood. Genotyping was performed for SOD2 rs4880, CAT rs1001179, GPX1 rs1050450, GSTP1 rs1695, GSTM1 gene deletion, GSTT1 gene deletion, IL1B rs1143623, IL1B rs16944, IL6 rs1800795 and TNF rs1800629. We found a nominally significant association of GSTM1 gene deletion with decreased risk of ocular hypertension and a protective role of IL1B rs16944 and IL6 rs1800629 in the risk of glaucoma. The CT and TT genotypes of GPX1 rs1050450 were significantly associated with advanced disease, lower intraocular pressure and a larger vertical cup–disc ratio. In conclusion, genetic variability in IL1B and IL6 may be associated with glaucoma risk, while GPX and TNF may be associated with the glaucoma phenotype. In the future, improved knowledge of these pathways has the potential for new strategies and personalised treatment of glaucoma.

Genetic pre-screening for glaucoma in population-based epidemiology: protocol for a double-blind prospective screening study within Lifelines (EyeLife)

Background

Early detection of glaucoma is paramount to maintain patients’ eyesight, however glaucomatous vision loss tends to begin in the periphery with up to 50% of patients unaware they are affected. Because glaucomatous vision loss is permanent, screening appears attractive, but currently is not cost-effective. Therefore we aim to investigate the utility of genetic pre-screening for glaucoma in a population-based setting, called EyeLife.

Methods

EyeLife adopts a double blind prospective design with contrasting groups. Selected participants (n = 1600) from the Lifelines cohort are 55 years of age or older, and of either the highest or lowest 20% of the genetic risk distribution for glaucoma. We obtained a highly curated list of genetic variants from the literature to obtain each participants’ genetic risk for glaucoma. Participants will undergo comprehensive ophthalmic screening. The primary outcome is the relative risk of glaucoma given a high genetic risk compared to a low genetic risk.

Discussion

If genetic pre-screening is successful, it will increase the yield of a glaucoma screening program by focusing on high-risk individuals. This, in turn, may improve long-term visual health of middle-aged and elderly people.

Trial registration

Ethics approval was obtained on January 31, 2019, and the study was retrospectively registered with the Netherlands Trial Register (NL8718) on the 17th of June, 2020.

Icare versus Goldmann in a randomised middle-aged population : The influence of central corneal thickness and refractive errors

PURPOSE

The aim of this study was to compare the measurements of intraocular pressure by two tonometers, the Icare rebound tonometer and the Goldmann applanation tonometer, in a randomised screening study. The influence of refraction and central corneal thickness on the measurements was also evaluated.

METHODS

Intraocular pressure was measured with rebound tonometer and Goldmann applanation tonometer in 1266 participants; refraction and central corneal thickness were also determined. One randomised eye of each participant was selected for this report's analysis. A Bland-Altman plot was used to compare the values obtained with the two devices.

RESULTS

The correlation between rebound tonometer and Goldmann applanation tonometer was good: the intraclass correlation coefficient (r) between the two methods was 0.735 (p < 0.001). The mean difference (rebound tonometer-Goldmann applanation tonometer) was 0.11 ± 2.3 mmHg. The difference was not statistically significant (95% confidence interval: 0.11 to 0.13, p = 0.09). With increasing central corneal thickness, not only did intraocular pressure values with both devices increase, but the difference between them also increased. Refraction (spherical equivalent) did not influence intraocular pressure or the rebound tonometer-Goldmann applanation tonometer difference. However, high astigmatism (≥2D) exerted an influence on intraocular pressure values taken with Goldmann applanation tonometer.

CONCLUSION

Measurements with rebound tonometer and Goldmann applanation tonometer are relatively uniform although rebound tonometer slightly overestimated intraocular pressure. Both rebound tonometer and Goldmann applanation tonometer and the difference between these devices were affected by central corneal thickness but not by refraction. Higher astigmatism affected Goldmann applanation tonometer more than rebound tonometer. It is concluded that rebound tonometer is a reliable method for measuring intraocular pressure in a population-based screening study.

Diagnostic performance of modern imaging instruments in glaucoma screening

AIM

To evaluate the applicability of imaging devices (spectral-domain optical coherence tomography (Cirrus SD-OCT), scanning laser polarimetry (GDx) and scanning laser ophthalmoscopy (Heidelberg Retinal Tomograph, HRT3)) for glaucoma screening in a middle-aged unselected population.

METHODS

Participants of the population-based Northern Finland Birth Cohort Eye Study, aged 45 to 49 years, underwent a comprehensive eye examination including modern imaging with five methods (retinal nerve fibre layer (RNFL) and macular ganglion cell layer +inner plexiform layer (GCIPL) analysis and their combination with SD-OCT, GDx and HRT). The performance of the automated classification of the imaging devices was assessed using a clinical glaucoma diagnosis as reference, that is, the '2 out of 3' rule based on the evaluation of optic nerve head and RNFL photographs and visual fields.

RESULTS

We examined 6060 eyes of 3039 subjects; in the clinical evaluation, glaucomatous damage was found in 33 subjects (1.1%) in 43 eyes. The following sensitivities were obtained; RNFL analysis (53%), GCIPL analysis (50%), OCT combination analysis (61%), GDx (56%) and HRT (31%) with corresponding specificities of 95%, 92%, 90%, 88% and 96%. The area under the curve values were 0.76, 0.73, 0.75, 0.75 and 0.73, respectively. Post-test probabilities of glaucoma after positive imaging finding with each of these methods in this unselected population were 11%, 7%, 6%, 5% and 7%, respectively.

CONCLUSION

Screening capabilities of the OCT, GDx and HRT were rather similar. The accuracy of all evaluated parameters was only moderate and thus screening with these parameters alone is not reliable.

Relationship between ocular biometry and severity of primary angle-closure glaucoma: relevance for predictive, preventive, and personalized medicine

Background

Several ocular factors have been identified for primary angle-closure glaucoma (PACG), such as a small cornea, elevated intraocular pressure (IOP), shallow anterior chamber, and short axial length (AL). However, the relationship between the severity of PACG and various ocular parameters [IOP, anterior chamber depth, AL, central corneal thickness] is not fully understood.

Methods

A 7-year cross-sectional study. A total of 2254 eyes of 1312 PACG patients (females = 856 [1479 eyes] and males = 456 [775 eyes]) were included. A detailed eye examination was performed. The participants were categorized into gender subgroups followed by subdivision into three different severity groups according to their mean deviation (MD) of the visual fields results as follows: mild (MD ≤ 6 dB), moderate (MD 6-12 dB), and severe (MD > 12 dB) PACG. The associations of ocular biometry with severity of PACG were analyzed using paired Student's t test, multivariate linear regression, and logistic regression analysis.

Results

There was a significant positive correlation between the MD and AL in the female subgroup (B = 0.663, p = 0.001, 95%CI = 1.070 to 1.255) but not in the male subgroup. Increased AL levels (mild [OR = 1], moderate [OR = 1.047, p = 0.062, 95%CI = 0.947 to 2.462], and severe [OR = 1.274, p < 0.001, 95%CI = 1.114 to 1.457]) were only associated with the severity of PACG in females. Paired Student's t tests showed that the long AL female eyes have a higher MD value than in the short AL female eyes (mean difference = 3.09, t = 6.846, p < 0.001) in the same subjects, but not in the male subgroup (p = 0.648).

Conclusions

The AL was positively and significantly related to the severity of PACG in female but not male subjects. This finding refers to the PACG pathogenesis and suggests the use of AL assessment in glaucoma monitoring, diagnosis, and progression. This may contribute to further development of personalized strategies in preventive medicine.