Jau-Der Ho

Validity of the keratometric index: Evaluation by the Pentacam rotating Scheimpflug camera

PURPOSE: To determine the keratometric index based on actual measurements of the anterior and posterior corneal surfaces using a rotating Scheimpflug camera (Pentacam, Oculus) and evaluate the accuracy of this keratometric index in estimating total and posterior corneal powers. SETTING: Departments of Ophthalmology, Taipei Medical University Hospital and Taipei City Hospital, Taipei, Taiwan. METHODS: The right eye of 221 subjects was measured with the Pentacam system. The radius of the best‐fit sphere for the anterior corneal surface (rant) and posterior corneal surface (rpost), mean radius of simulated keratometry (rsimK), and central corneal thickness were obtained. The ratio of rant to rpost (AP ratio) and keratometric index were calculated in each eye. RESULTS: The means for rant, rpost, rsimK, and AP ratio were 7.75 mm ± 0.28 (SD), 6.34 ± 0.28 mm, 7.75 ± 0.27 mm, and 1.223 ± 0.034 mm, respectively. These parameters were normally distributed. The mean calculated keratometric index (Ncal) was 1.3281 ± 0.0018. Using the keratometric indices of 1.3281 (Ncal), 1.3315 (Gullstrand schematic eye), and 1.3375 (conventional), the mean arithmetic and absolute estimation errors for the total corneal power were, 0.00 ± 0.24 diopter (D) and 0.17 ± 0.17 D, 0.43 ± 0.23 D and 0.45 ± 0.21 D, and 1.21 ± 0.24 D and 1.21 ± 0.24 D, respectively. The total corneal power was predicted to within ±0.50 D of the actual value in 95.0%, 60.2%, and 0.9% of eyes, respectively. The mean arithmetic and absolute estimation errors for the posterior corneal power using an AP ratio of 1.223 (this study) or 1.132 (Gullstrand schematic eye) were 0.00 ± 0.17 D and 0.13 ± 0.12 D and 0.47 ± 0.18 D and 0.47 ± 0.17 D, respectively. The posterior corneal power was estimated to within ±0.50 D of the actual value in 97.7% and 60.2% of eyes, respectively. CONCLUSION: Using the Pentacam‐derived keratometric index improved the prediction accuracies of total and posterior corneal powers.

Effects of aging on anterior and posterior corneal astigmatism.

Purpose: To evaluate age-related changes in astigmatism of both corneal surfaces and the whole cornea. Methods: The right eyes of 370 subjects were measured with a rotating Scheimpflug camera (Pentacam). Astigmatisms of the anterior and posterior corneal surfaces were determined. The total corneal astigmatism was derived using power vector summation and vergence tracing. Age-related changes to corneal astigmatism were evaluated using polar value analysis (both in diopter and millimeter). Results: For the anterior and total cornea, the proportion of with-the-rule astigmatisms decreased and those of oblique and against-the-rule astigmatisms increased with age. For the posterior cornea, most eyes displayed against-the-rule astigmatisms in all age groups. There was a significant trend toward against-the-rule astigmatism associated with increasing age for both anterior and total corneal astigmatisms (mean changes of −0.18 and −0.16 diopters/5 years, respectively), and toward with the rule in posterior corneal astigmatism (a mean change of 0.022 diopters/5 years). Regarding shape changes, a “flat meridian toward a more vertical orientation” trend with increasing age for both the anterior and posterior corneal surfaces was observed (mean changes of 0.0295 and 0.0224 mm/5 years, respectively). The posterior corneal surface compensated for the astigmatism arising from the anterior corneal surface in 91.4% and 47.7% of eyes in the 21-30 and ≥71 years groups, respectively. Conclusions: There were age-related shifts toward against-the-rule and with-the-rule astigmatisms for the anterior and posterior corneal surfaces, respectively. The compensating effects of the posterior corneal surface on anterior corneal astigmatism decreased with advancing age.

Trends and outcomes of treatment for primary rhegmatogenous retinal detachment: a 9-year nationwide population-based study.

PurposeTo determine the trends and outcomes for treating primary rhegmatogenous retinal detachment (RRD) in a nationwide population-based study in Taiwan.MethodsWe collected admission data during the period of 1997–2005, from the Taiwan National Health Insurance Research Database, a source that covers over 96% of Taiwans 23 million citizens. Totally 28 911 patients with a first-time admission diagnosis of RRD (ICD-9-CM codes 361 to 361.07) and undergoing surgical treatment (scleral buckling (SB), pars plana vitrectomy (PPV), or their combination) were identified. The utilized operation type, 180-day readmission rate for recurrent retinal detachment, length of hospital stay, and admission charge were obtained. Contingency table/χ 2 test and t-test were employed for the statistical analysis.ResultsPrimary PPV (with or without SB) was a primary procedure in 47.3% of cases in 1997. This rate rose significantly to 61.2% in 2005. A significant decrease in the total 180-day readmission rate occurred from 18.95% in 1997 to 13.81% in 2005. These rates also significantly decreased for each surgical modality (from 16.30 to 11.38% for SB, from 21.29 to 14.69% for PPV, and from 22.99 to 16.55% for PPV+SB). The length of hospital stay decreased for each surgical modality between 1997 and 2005.ConclusionsThere was a significant trend towards more frequently employing primary PPV (with or without SB) for the management of primary RRD. In addition, significant improvements in the primary success rates were shown for each surgical modality group and for total samples between 1997 and 2005.

Estimation of the effective lens position using a rotating Scheimpflug camera

PURPOSE: To describe a no‐history method of estimating the effective lens position (ELP) for double‐K intraocular lens (IOL) power calculation in eyes that had previous refractive surgery. SETTING: Departments of Ophthalmology, Taipei Medical University Hospital and Taipei City Hospital, Taipei, Taiwan. METHODS: The corneal height (Hm) and anterior chamber diameter (AGm) in 106 unoperated eyes were measured using a rotating Scheimpflug camera. The theoretical anterior corneal radius (Rrt) was then derived from Hm and AGm by regression and rearrangement of the Fyodorov equation. The ELP estimate was then calculated from Rrt. The performance of this ELP estimation method in double‐K IOL power calculation and the performance of other methods were compared retrospectively in 11 eyes having cataract surgery that had previous refractive surgery. The refractive results 9 to 12 weeks after cataract surgery were selected for data analysis. RESULTS: The new ELP estimation method, combined with the BESSt formula or the Savini et al. method for estimating post refractive–surgery corneal power (Kpost) in the double‐K SRK/T formula, provided the best IOL power prediction results. The mean arithmetic and absolute IOL prediction errors were −0.05 ± 0.62 diopters (D) and 0.49 ± 0.34 D, respectively, when combined with the BESSt formula and 0.03 ± 0.73 D and 0.60 ± 0.36 D, respectively, when combined with the Savini et al. method. With either combination, all 11 eyes were within ±1.00 D of the refractive prediction error. CONCLUSION: This ELP estimation method may be helpful for IOL power calculation in post refractive–surgery eyes when historical data are unavailable.

Dementia is associated with open-angle glaucoma: a population-based study

PurposePrevious epidemiologic studies that focused on the association between open-angle glaucoma (OAG) and dementia showed inconsistent results. In the present study, we explored the association between OAG and dementia in an ethnic Chinese (ie, Taiwanese) population using a population-based data set.MethodsWe retrieved data on study subjects for this case-control study from the Longitudinal Health Insurance Database 2000. We identified 7770 patients who had a diagnosis of dementia as cases, and 7770 subjects matched in terms of sex and age, which were randomly extracted as controls. A conditional logistic regression conditioned on age group, sex, and index year was used to assess the association of dementia with previously diagnosed OAG among the sampled patients.ResultsOf 15 540 patients, 1.70% had prior OAG, including 2.02% of the dementia group and 1.38% of the controls. After adjusting for patient socioeconomic characteristics and comorbid medical disorders, dementia patients were more likely to have had prior OAG than controls (odds ratio (OR): 1.44; 95% confidence interval (CI): 1.12–1.85; P<0.01). In addition, female dementia patients were more likely to have had prior OAG than controls (OR: 1.93; 95% CI: 1.35–2.77; P<0.001), whereas no statistical difference in prior OAG between male dementia patients and controls was found.ConclusionsFemale dementia patients were associated with a higher proportion of prior OAG than were the controls.

Increased risk of open-angle glaucoma following chronic rhinosinusitis: a population-based matched-cohort study

PurposeAnatomically, the eyes and paranasal sinuses are neighboring structures and some studies have mentioned eye disease in conjunction with chronic rhinosinusitis (CRS). However, to the best of our knowledge, no prior research has investigated the risk of developing open-angle glaucoma (OAG) among CRS patients. This study aims to provide an estimated risk of developing OAG among patients with CRS by using a population-based data set in Taiwan.MethodsThis retrospective cohort study used data sourced from the ‘Longitudinal Health Insurance Database 2000’. A total of 15 642 CRS patients were included in the study cohort and 46 926 subjects were randomly extracted as a comparison cohort. A cox proportional-hazards regression analysis was performed to calculate the 5-year risk of subsequently developing OAG following a diagnosis of CRS between the study cohort and the comparison cohort.ResultsThe incidence rate of developing OAG over the 5-year follow-up period was 5.45 (95% CI: 4.95–5.98) per 1000 person-years for the study cohort and 2.80 (95% CI: 2.60–3.03) per 1000 person-years for the comparison cohort. After censoring the cases that died over the 5-year period and adjusting for the factors of monthly income, geographic region, hypertension, diabetes, coronary heart disease, hyperlipidemia, and hypothyroidism the hazard ratio for developing OAG over the 5-year period for subjects with CRS to subjects without CRS was 1.73 (95% CI: 1.53–1.96).ConclusionWe found that those subjects with CRS had a significantly higher risk of developing OAG over the 5-year follow-up period as compared with subjects without CRS.

Surgeon age and operative outcomes for primary rhegmatogenous retinal detachment: a 3-year nationwide population-based study

PurposeThe aim was to study the association of surgeon age with operative outcomes for primary rhegmatogenous retinal detachment (RRD) in Taiwan.MethodsA total of 7427 adult patients of primary RRD who were treated by 284 ophthalmologists with scleral buckling (SB), pars plana vitrectomy (PPV), or their combination from 2002 to 2004 were identified in the Taiwan National Health Insurance Research Database. The adjusted odds ratios (OR) of 180-day readmission between ophthalmologist age groups were calculated.ResultsFor SB, patients treated by ophthalmologists aged ⩾51 years had a greater 180-day readmission rate (OR=1.44, 95% confidence interval (CI)=1.01–2.07, P<0.05) than those treated by ophthalmologists aged 41–50 years. For PPV, patients treated by ophthalmologists aged ⩽40 years had a lower 180-day readmission rate than those treated by ophthalmologists aged 41–50 and ⩾51 years (OR=0.58 and 0.22, 95% CI=0.47–0.71 and 0.13–0.63, P<0.001 and <0.001, respectively). For PPV+SB, patients treated by ophthalmologists aged ⩾51 years had a higher 180-day readmission rate than those treated by ophthalmologists aged ⩽40 and 41–50 years (OR=3.32 and 2.45, 95% CI=2.29–4.21 and 1.36–4.40, P<0.01 and <0.01, respectively). The absolute differences in the 180-day readmission rate by surgeon age ranged from −0.1 to 3.2%. The proportions of selecting primary SB (without PPV) as the treatment modality were 33.1, 35.6, and 70.6% for the ⩽40-, 41-to 50-, and ⩾51-year groups, respectively.ConclusionsSurgeon age is a relatively weak predictor for the outcomes of primary RRD surgery in aggregate in Taiwan and certainly not appropriate for discriminating performance among individual surgeons.

Association between open-angle glaucoma and neovascular age-related macular degeneration: a case-control study

PurposeTo investigate the relationship between previously diagnosed open-angle glaucoma (OAG) and neovascular age-related macular degeneration (AMD) using a routine insurance dataset.MethodsThis study retrieved data from the Taiwan Longitudinal Health Insurance Database 2005. We found 3282 patients with neovascular AMD as cases and 13 128 sex- and age-matched subjects without neovascular AMD as controls. Conditional logistic regressions were performed to evaluate the association of neovascular AMD with previously diagnosed OAG among the sampled patients.ResultsOf the 16 410 sampled patients, 2.55% had previously diagnosed OAG, 5.06 and 1.92% for the cases and controls, respectively. The logistic regression analysis showed that the odds ratio (OR) of previously diagnosed OAG for cases was 2.45 (OR: 2.45; 95% confidence interval: 1.99–3.01) compared with the controls after adjusting for potential confounders. In addition, the adjusted ORs for previously diagnosed OAG were similar for patients with AMD in both genders (with an adjusted OR of 2.49 for males and 2.39 for females). Furthermore, it shows that OAG was significantly associated with neovascular AMD regardless of sex even after adjusting for monthly income, geographic region, urbanisation level, and comorbidities (with adjusted ORs of 2.49 for males and 2.39 for females).ConclusionsThis study demonstrated that patients with neovascular AMD had a higher odds of previously diagnosed OAG compared with those patients without neovascular AMD regardless of sex.

Increased risk of neovascular age-related macular degeneration in patients with herpes zoster ophthalmicus: a retrospective cohort study

decrease in the study eye is a direct consequence of the DEX 0.7 injection. In addition, this study confirmed the findings of Kim et al. (2016) that subfoveal choroidal thickness significantly decreases after DEX 0.7 injection in eyes with DME. In conclusion, choroidal volume decreased significantly in eyes with DME after DEX 0.7 injection, while choroidal volume in the fellow eyes remained unchanged.