[Odontogenic infection as cause of orbital cellulitis]. / Een dentale oorzaak van orbitale cellulitis.

BACKGROUND: Orbital cellulitis is a potentially life-threatening condition. Compression of the optical nerve can cause total or partial loss of vision. Early diagnosis is crucial to prevent complications. In case of a unilateral sinusitis as cause of a unilateral orbital cellulitis complete clinical and dental examination combined with imaging are essential in diagnostics. CASE DESCRIPTION: A 53-year-old man presented with left eye movement impairment, intermittent diplopia and moderate swelling of the left lower eyelid. His diagnosis was post septal orbital cellulitis and despite administration of oral antibiotics no clinical improvement was observed. Orbital imaging by CT could not exclude a dental cause of his unilateral maxillary sinusitis. He was referred to the department of oral and maxillofacial surgery where clinical examination showed a dental cause. After removal of two decayed upper molars a complete recovery was accomplished. CONCLUSION: Odontogenic causes for unilateral orbital cellulitis should always be considered in diagnostics in adults. Clinical presentation and dental examination combined with adequate imaging can confirm the diagnosis.

What did we learn in 35 years of research on nutrition and supplements for age-related macular degeneration: a systematic review.

The aim of this paper is to summarize all available evidence from systematic reviews, randomized controlled trials (RCTs) and comparative nonrandomized studies (NRS) on the association between nutrition and antioxidant, vitamin, and mineral supplements and the development or progression of age-related macular degeneration (AMD). The Cochrane Database of Systematic Reviews, Cochrane register CENTRAL, MEDLINE and Embase were searched and studies published between January 2015 and May 2021 were included. The certainty of evidence was assessed according to the GRADE methodology. The main outcome measures were development of AMD, progression of AMD, and side effects. We included 7 systematic reviews, 7 RCTs, and 13 NRS. A high consumption of specific nutrients, i.e. ß-carotene, lutein and zeaxanthin, copper, folate, magnesium, vitamin A, niacin, vitamin B6, vitamin C, docosahexaenoic acid, and eicosapentaenoic acid, was associated with a lower risk of progression of early to late AMD (high certainty of evidence). Use of antioxidant supplements and adherence to a Mediterranean diet, characterized by a high consumption of vegetables, whole grains, and nuts and a low consumption of red meat, were associated with a decreased risk of progression of early to late AMD (moderate certainty of evidence). A high consumption of alcohol was associated with a higher risk of developing AMD (moderate certainty of evidence). Supplementary vitamin C, vitamin E, or ß-carotene were not associated with the development of AMD, and supplementary omega-3 fatty acids were not associated with progression to late AMD (high certainty of evidence). Research in the last 35 years included in our overview supports that a high intake of specific nutrients, the use of antioxidant supplements and adherence to a Mediterranean diet decrease the risk of progression of early to late AMD.

Procedural aspects of the organization of the comprehensive European Board of Ophthalmology Diploma examination.

The comprehensive European Board of Ophthalmology Diploma (EBOD) examination is one of 38 European medical specialty examinations. This review aims at disclosing the specific procedures and content of the EBOD examination. It is a descriptive study summarizing the present organization of the EBOD examination. It is the 3rd largest European postgraduate medical assessment after anaesthesiology and cardiology. The master language is English for the Part 1 written test (knowledge test with 52 modified type X multiple-choice questions) (in the past the written test was also available in French and German). Ophthalmology training of minimum 4 years in a full or associated European Union of Medical Specialists (UEMS) member state is a prerequisite. Problem-solving skills are tested in the Part 2 oral assessment, which is a viva of 4 subjects conducted in English with support for native language whenever feasible. The comprehensive EBOD examination is one of the leading examinations organized by UEMS European Boards or Specialist Sections from the point of number of examinees, item banking, and item contents.

Retinal blood flow is increased in type 1 diabetes mellitus patients with advanced stages of retinopathy.

BACKGROUND: Diabetic retinopathy (DRP) is a common microvascular complication seen in patients with type 1 diabetes mellitus (T1DM). The effects of T1DM and concomitant (proliferative) DRP on retinal blood flow are currently unclear. Therefore, we measured retinal vascular blood flow in T1DM patients with and without DRP and non-diabetic controls. We further assessed the acute effects of panretinal photocoagulation on retinal microvascular bloodflow in eight patients with diabetes. METHODS: Thirty-three T1DM patients with proliferative DRP, previously treated with panretinal photocoagulation (pDRP), 11 T1DM patients with untreated non-proliferative retinopathy (npDRP) and 32 T1DM patients without DRP (nDRP) were compared with 44 non-diabetic gender-matched controls. Using scanning laser Doppler flowmetry (HRF, Heidelberg) blood flow in the retinal microvasculature was measured temporal and nasal of the optic disc and averaged into one flow value per eye. The right eye was used as a default for further analyses. Eight patients with novel proliferative retinopathy (4 T1DM and 4 with type 2 diabetes) were measured before and several months after photocoagulation. Between-group differences in retinal blood flow were assessed using ANOVA corrected for multiple comparisons (Bonferroni). RESULTS: Retinal blood flow was higher in the treated pDRP compared with the nDRP group and controls (all P Bonferroni < 0.01). Furthermore, there was a positive linear trend for blood flow with lowest blood flow in the control group and highest in the pDRP group (P-for-trend < 0.01). In the eight patients with novel proliferative retinopathy, blood flow did not significantly change before and after panretinal photocoagulation (P > 0.05). Using regression analysis, no variables were found as predictors of retinal blood flow. CONCLUSIONS: In comparison with controls and nDRP patients, retinal blood flow significantly increased in the pDRP group, which previously underwent photocoagulation treatment, but not in the npDRP patients. These changes may be a consequence of a failing vascular autoregulation in advanced diabetic retinopathy.

Evaluation of adding item-response theory analysis for evaluation of the European Board of Ophthalmology Diploma examination.

PURPOSE: To investigate whether introduction of item-response theory (IRT) analysis, in parallel to the 'traditional' statistical analysis methods available for performance evaluation of multiple T/F items as used in the European Board of Ophthalmology Diploma (EBOD) examination, has proved beneficial, and secondly, to study whether the overall assessment performance of the current written part of EBOD is sufficiently high (KR-20≥ 0.90) to be kept as examination format in future EBOD editions. METHODS: 'Traditional' analysis methods for individual MCQ item performance comprise P-statistics, Rit-statistics and item discrimination, while overall reliability is evaluated through KR-20 for multiple T/F items. The additional set of statistical analysis methods for the evaluation of EBOD comprises mainly IRT analysis. These analysis techniques are used to monitor whether the introduction of negative marking for incorrect answers (since EBOD 2010) has a positive influence on the statistical performance of EBOD as a whole and its individual test items in particular. RESULTS: Item-response theory analysis demonstrated that item performance parameters should not be evaluated individually, but should be related to one another. Before the introduction of negative marking, the overall EBOD reliability (KR-20) was good though with room for improvement (EBOD 2008: 0.81; EBOD 2009: 0.78). After the introduction of negative marking, the overall reliability of EBOD improved significantly (EBOD 2010: 0.92; EBOD 2011:0.91; EBOD 2012: 0.91). CONCLUSION: Although many statistical performance parameters are available to evaluate individual items, our study demonstrates that the overall reliability assessment remains the only crucial parameter to be evaluated allowing comparison. While individual item performance analysis is worthwhile to undertake as secondary analysis, drawing final conclusions seems to be more difficult. Performance parameters need to be related, as shown by IRT analysis. Therefore, IRT analysis has proved beneficial for the statistical analysis of EBOD. Introduction of negative marking has led to a significant increase in the reliability (KR-20 > 0.90), indicating that the current examination format can be kept for future EBOD examinations.

History and future of the European Board of Ophthalmology Diploma examination.

PURPOSE: The European Board of Ophthalmology Diploma (EBOD) examination has evolved over the last few years, especially with the introduction of negative marking (-0.5 points) for incorrect or blank answers (0 points for don't know option), which aimed to improve the quality and reliability of the examination. METHODS: In 2010, negative marking at the written part of the EBOD examination has been introduced in an attempt to improve not only the reliability of the examination as entity but also the statistical performance parameters of the individual questions. As lower pass rates and discrimination of female candidates are feared by the general public when negative marking is concerned, these parameters have been explicitly investigated. RESULTS: Introduction of negative marking has not only lead to improved reliability of the EBOD examination (increased Cronbach's alpha value: ≤0.80 without and ≥0.90 with negative marking), but also to improved statistical performance parameters of the individual questions. The pass rate of the EBOD examination has proven to remain at the same high level as without negative marking (around 90%). Furthermore, although female candidates do seem to have different answering strategies (p < 0.01, use of don't know option), no statistically significant difference has been found between total scores of male and female candidates (p > 0.05). CONCLUSION: Introduction of negative marking at the written EBOD examination has proven to be beneficial, not only for the organizers (improvement of the statistical performance of the examination and its questions), but also for candidates (better discrimination with borderline candidates). These results have been obtained without evidence of lower pass rates or discrimination of female candidates.

Randomized controlled trial on the effects of CCTV training on quality of life, depression, and adaptation to vision loss.

PURPOSE: In addition to performance-based measures, vision-related quality of life (QOL) and other subjective measures of psychosocial functioning are considered important outcomes of training in the visually impaired. In a multicenter, masked, randomized controlled trial, subjective effects of training in the use of closed-circuit televisions (CCTV) were investigated. METHODS: Patients (n = 122) were randomized either to a treatment group that received usual delivery instructions from the supplier combined with concise outpatient training, or to a control group that received delivery instructions only. Subjective outcomes were the low vision quality-of-life questionnaire (LVQOL), EuroQOL 5 dimensions, adaptation to age-related vision loss (AVL), and the Center of Epidemiologic Studies Depression scales. Linear mixed models were used to investigate treatment effects. Differential effects of patient characteristics were studied by implementing higher order interactions into the models. RESULTS: From baseline to follow-up, all patients perceived significantly less problems on the reading and fine work dimension (-28.8 points; P < 0.001) and the adaptation dimension (-4.67 points; P = 0.04) of the LVQOL. However, no treatment effect was found based on the intention-to-treat analysis. CONCLUSIONS: This study demonstrated the effect of receiving and using a CCTV on two vision-related QOL dimensions; however, outpatient training in the use of CCTVs had no additional value. (trialregister.nl number, NTR1031.).

RB1 mutations and second primary malignancies after hereditary retinoblastoma.

Survivors of hereditary retinoblastoma have a high risk of second primary malignancies, but it has not been investigated whether specific RB1 germline mutations are associated with greater risk of second primary malignancies in a large cohort. We conducted a retrospective cohort study of 199 survivors of hereditary retinoblastoma with a documented RB1 germline mutation diagnosed between 1905 and 2005. In total, 44 hereditary retinoblastoma survivors developed a second primary malignancy after a median follow-up of 30.2 years (range 1.33-76.0). A significantly increased risk of second primary malignancy was observed among carriers of one of the 11 recurrent CGA>TGA nonsense RB1 mutations (hazard ratio (HR) = 3.53; [95% confidence interval (CI) = 1.82-6.84]; P = .000), and there was a significantly lower risk for subjects with a low penetrance mutation (HR = .19; [95% CI = .05-.81]; P = .025). Our findings suggest a genotype-phenotype correlation for second primary cancers of retinoblastoma survivors and may impact on long-term surveillance protocols of patients with hereditary retinoblastoma, if confirmed by future studies.

A systematic review of the adverse events of intravitreal anti-vascular endothelial growth factor injections.

BACKGROUND: Intravitreal ranibizumab and pegaptanib are registered for neovascular age-related macular degeneration. No formal safety study has been conducted for intravitreal bevacizumab. These anti-vascular endothelial growth factor (anti-VEGF) drugs are being used on a large scale in daily practice for different ocular diseases. The objective of the present study was to systematically assess and compare the incidences of adverse events of anti-VEGFs. METHODS: A systematic search was conducted in April 2009 with no date restrictions in PubMed, Embase, Toxline, and the Cochrane library. We used the terms pegaptanib, bevacizumab, ranibizumab, intravitreal, and specific and general terms for adverse events. Studies describing adverse events after anti-VEGF injections and the official safety data were included. RESULTS: Two hundred and seventy-eight articles were included, and the incidences of adverse events were calculated separately for effect, safety, and specific side effect studies. The incidences of serious ocular and nonocular adverse events were approximately below 1 per 100 injections for intravitreal bevacizumab, intravitreal ranibizumab, and intravitreal pegaptanib. Most mild ocular adverse events were below 5 per 100 injections. CONCLUSION: The reported rates of serious adverse events were low after anti-VEGF injections. There is no sufficient evidence to conclude that there is a difference in incidences between the anti-VEGFs.

Restrictions in daily life after retinoblastoma from the perspective of the survivors.

BACKGROUND: Little is known about the impact of retinoblastoma (RB) on the health status of survivors in terms of disabilities and worries, both of which may restrict participation in activities of daily life. METHODS: In this population-based cross-sectional study, content analysis was used to extract data on perceived restrictions and worries, from semi-structured interviews held with 156 RB survivors aged 8-35 years. The International Classification of Functioning Disabilities and Health (ICF) was used as a framework. RESULTS: Of all survivors, 55% perceive RB-related restrictions in daily life activities (school, professional career, mobility, self-care, intimate relationships). Young/adolescent survivors (6%) and adult survivors (15%) frequently report anxiety about developing a second primary tumor (SPT). Compared with the general population, RB survivors did not differ in rates of employment or marital status. However, special educational services were more frequently offered, and the level of completed education was lower. CONCLUSION: RB has influenced the lives of most survivors and, even though their prognosis was good, illness-related restrictions are common. Especially fear of developing SPT and of further loss of vision are important life-long problems, and many survivors had special education needs. The ICF might serve as a bridge between families and professionals, because this classification may facilitate early detection of problems.

[The sense and nonsense of waiting--waiting in ophthalmological practice]. / Wachten, zin en zonde-- wachten in de oogheelkundige praktijk.

Waiting is commonplace in many areas of health care and has become a topical and politically important issue in the provision of healthcare services. Whilst managers and governments (the Treek agreement ('Treekoverleg') on benchmarking in the Dutch health services, 2000) search for solutions to this problem and have formulated norms for what they consider acceptable, there is little information concerning the clients' own opinions. An understanding of these could be an important consideration during policy-making and political discussions. In the ophthalmological clinic it has been established that the waiting lists for cataract surgery should not exceed 6 months because patients may experience negative outcomes if they have to wait longer than this. Solutions to the problems of long waiting can be found in the use of digital communication methods or integration of eye-care with other professionals such as general practitioners. In some cases, having to wait may actually have positive aspects.

Co-morbidity and visual acuity are risk factors for health-related quality of life decline: five-month follow-up EQ-5D data of visually impaired older patients.

BACKGROUND: Co-morbidity is a common phenomenon in the elderly and is considered to be a major threat to quality of life (QOL). Knowledge of co-existing conditions or patient characteristics that lead to an increased QOL decline is important for individual care, and for public health purposes. In visually impaired older adults, it remains unclear which co-existing conditions or other characteristics influence their health-related QOL. Our aim was to present a risk profile of characteristics and conditions which predict deterioration of QOL in visually impaired older patients. METHODS: Analyses were performed on data from an observational study among 296 visually impaired older patients from four Dutch hospitals. QOL was measured with the EuroQol-5D (EQ-5D) at baseline and at five-month follow-up. Nine co-existing condition categories (musculoskeletal; diabetes; heart; hypertension; chronic obstructive pulmonary disease (COPD) or asthma; hearing impairment; stroke; cancer; gastrointestinal conditions) and six patient characteristics (age; gender; visual acuity; social status; independent living; rehabilitation type) were tested in a linear regression model to determine the risk profile. The model was corrected for baseline EQ-5D scores. In addition, baseline EQ-5D scores were compared with reference scores from a younger visually impaired population and from elderly in the general population. RESULTS: From the 296 patients, 50 (16.9%) were lost to follow-up. Patients who reported diabetes, COPD or asthma, consequences of stroke, musculoskeletal conditions, cancer, gastrointestinal conditions or higher logMAR Visual Acuity values, experienced a lower QOL. After five months, visual acuity, musculoskeletal conditions, COPD/asthma and stroke predicted a decline in QOL (R2 = 0.20). At baseline, the visually impaired older patients more often reported moderate or severe problems on most EQ-5D dimensions than the two reference groups. CONCLUSION: In visually impaired older patients, visual acuity, musculoskeletal conditions, COPD/asthma and stroke predicted a relatively rapid decline in health-related QOL. With this risk profile, a specific referral by the ophthalmologist to another sub-specialty may have a beneficial effect on the patient's health-related QOL. A referral by the ophthalmologist or optometrist to a multidisciplinary rehabilitation service seems appropriate for some patients with co-morbidity. The current results need to be confirmed in studies using pre-structured questionnaires to assess co-morbidity.

Measuring the refractive properties of the diabetic eye during blurred vision and hyperglycaemia using aberrometry and Scheimpflug imaging.

PURPOSE: This study aimed to measure the refraction and geometry in the diabetic eye during the presence and absence of hyperglycaemia and blurred vision, using aberrometry and Scheimpflug imaging. METHODS: Aberrometry and Scheimpflug imaging were used to examine ocular refraction and higher-order aberrations, as well as the shape of the cornea and the lens, in 25 patients with diabetes mellitus. From these parameters, the equivalent refractive index of the lens was calculated. Using paired t-tests, comparisons were made between a first series of measurements (Visit 1) taken in the presence of blurred vision and hyperglycaemia (> 10.0 micromol/l), and a second series of measurements (Visit 2) taken under normal conditions. RESULTS: The mean difference in blood glucose between Visits 1 and 2 was 5.9 mmol/l (standard deviation [SD] 3.1) (p < 0.0001). Both small hyperopic and myopic shifts of equivalent refractive error (ERE) were found in nine patients (mean absolute difference ERE: 0.38 D [SD 0.12]; p = 0.02). Furthermore, higher-order aberrations (root mean square [RMS] error) were slightly increased in four patients (mean difference RMS error: 0.07 microm [SD 0.02]; p = 0.04) at Visit 1, compared to Visit 2. No significant changes were observed in the shape of the cornea or lens in any of the patients. No significant correlations were found between changes in blood glucose levels and the measured parameters in diabetic eyes. CONCLUSIONS: The present study suggests that subjective symptoms of blurred vision during hyperglycaemia are not necessarily caused by changes in the refractive properties of the diabetic eye.

Risk of second malignancies in survivors of retinoblastoma: more than 40 years of follow-up.

BACKGROUND: Survivors of hereditary retinoblastoma have an elevated risk of developing second malignancies, but data on the risk in middle-aged retinoblastoma survivors (ie, those with more than 40 years of follow-up) are scarce. METHODS: Data from the Dutch retinoblastoma registry were used to analyze risks of second malignancies in 668 retinoblastoma survivors, diagnosed from 1945 to 2005 (median age = 24.9 years) and classified as having had hereditary or nonhereditary disease based on the presence of family history, bilateral disease, or a germline RB1 mutation. Standardized incidence ratios (SIRs) and absolute excess risks (AERs) of subsequent cancers in patients with hereditary and nonhereditary disease were estimated by comparison with Dutch sex-, age-, and calendar year-specific rates. Multivariable Cox regression and competing risk analyses were used to determine associations of treatment with risks of second malignancies. All statistical tests were two-sided. RESULTS: After a median follow-up of 21.9 years, the risk of second malignancies in survivors of hereditary retinoblastoma (SIR = 20.4, 95% confidence interval [CI] = 15.6 to 26.1) far exceeded the risk of survivors of nonhereditary retinoblastoma (SIR = 1.86, 95% CI = 0.96 to 3.24). Among patients with hereditary disease, treatment with radiotherapy was associated with a further increase in the risk of a subsequent cancer (hazard ratio = 2.81, 95% CI = 1.28 to 6.19). After 30 years of follow-up, elevated risks of epithelial cancers (lung, bladder, and breast) were observed among survivors of hereditary retinoblastoma. After 40 years of follow-up, the AER of a second malignancy among survivors of hereditary retinoblastoma had increased to 26.1 excess cases per 1000 person-years. The cumulative incidence of any second malignancy 40 years after retinoblastoma diagnosis was 28.0% (95% CI = 21.0% to 35.0%) for patients with hereditary disease. CONCLUSION: Our analysis of middle-aged hereditary retinoblastoma survivors suggests that these individuals have an excess risk of epithelial cancer. Lifelong follow-up studies are needed to evaluate the full spectrum of subsequent cancer risk in hereditary retinoblastoma survivors.

Changes in the internal structure of the human crystalline lens with diabetes mellitus type 1 and type 2.

PURPOSE: To investigate the effect of diabetes mellitus (DM) type 1 and type 2 on the internal structure of the lens. DESIGN: Observational cross-sectional study. PARTICIPANTS AND CONTROLS: One hundred seven patients with DM type 1, 106 patients with DM type 2, and 75 healthy control subjects. METHODS: Scheimpflug photography was used to image the lens of the right eye of 213 patients with DM and 75 healthy control subjects. The densitogram of the Scheimpflug image was used to indicate the nucleus and the different layers of the cortex of the lens. Lenses with cataract were excluded. MAIN OUTCOME MEASURES: The size of the nucleus and the different layers of the cortex of the lens. RESULTS: The nucleus and the different cortical layers of the DM type 1 lenses were significantly thicker compared with those of the control group (P<0.001). A significant association was found between the duration of DM type 1 and both the anterior and posterior cortex, its different layers, and the nucleus (P<0.001). The increase in the anterior and posterior cortex with the duration of DM was comparable with that of the nucleus. No important differences in the internal structure of the lens were found between the patients with DM type 2 and the control group. CONCLUSIONS: Diabetes mellitus type 1 has a significant effect on the internal structure of the lens. The difference in effect of DM type 1 and type 2 on internal lens structure suggests an essential difference in pathogenesis. Furthermore, the results of the present study may indicate that the increase in the size of the lens with DM type 1 is the result of a generalized swelling of the lens, affecting all its different parts.

Precision and reliability of retinal thickness measurements in foveal and extrafoveal areas of healthy and diabetic eyes.

PURPOSE: To determine the precision and reliability of retinal thickness measurements with an optical coherence tomograph (Stratus OCT 3; Carl Zeiss Meditec, Dublin, CA) and a retinal thickness analyzer (RTA; Talia Technology Ltd., Neve-Ilan, Israel) in foveal, parafoveal, and perifoveal areas. METHODS: Three measurements of all areas were performed within 1 hour on the same day with each instrument in the eyes of healthy volunteers and diabetic patients. The latter group was divided into eyes with and without macular edema. RESULTS: Measurement precision, expressed as the 95% limits of agreement (LA 95%), was significantly higher (i.e., a lower LA 95%, P < 0.01) for the OCT in comparison to the RTA in virtually all areas of the retina. Moreover, measurement reliability, expressed as the intraclass correlation coefficient, was high with the OCT (>0.90) and moderate to low with the RTA (0.26-0.89). A direct influence of macular edema itself on measurement precision of para- and perifoveal areas was found in the OCT measurements. CONCLUSIONS: The high measurement precision and reliability of the OCT suggests that this instrument is currently the most suitable technique for detection and follow-up of diabetic macular edema. When macular edema is present, the OCT can reliably detect changes of at least 36 microm at the fovea, 55 microm in parafoveal areas below a thickness of 744 microm, and 42 microm in perifoveal areas below a thickness of 1011 microm.

The influence of diabetes mellitus type 1 and 2 on the thickness, shape, and equivalent refractive index of the human crystalline lens.

PURPOSE: To study the influence of diabetes mellitus (DM) types 1 and 2 on the thickness, radius of curvature, equivalent refractive index, and power of the lens. DESIGN: Observational cross-sectional study. PARTICIPANTS AND CONTROLS: One hundred fourteen patients with DM type 1, 112 patients with DM type 2, and 75 control subjects. METHODS: Lens thickness and the anterior and posterior radius of the lens were measured by means of corrected Scheimpflug imaging. Ocular refraction was determined with Hartmann-Shack aberrometry. The equivalent refractive index and the power of the lens were calculated from these parameters. Several systemic parameters (e.g., duration of DM, glycated hemoglobin, and type of medication) and ocular comorbidity (e.g., level of diabetic retinopathy) were recorded. MAIN OUTCOME MEASURES: The thickness, anterior and posterior radii, equivalent refractive index, and power of the lens. RESULTS: The lenses of the patients with DM type 1 were significantly thicker and more convex, compared with those of the control group (P<0.001). Furthermore, there was a significant decrease in the equivalent refractive index of their lenses compared with the control group. No difference in lens parameters was found between the patients with DM type 2 and the control group. In the DM type 1 group, the duration of DM was an important determinant of lens biometry; the independent effects of the duration of DM per year on lens thickness, anterior radius, posterior radius, and equivalent refractive index were respectively 95%, 88%, 207%, and 45% of the effect of age per year. Lens power and ocular refraction were not affected by DM types 1 or 2. CONCLUSIONS: The results of the present study show that DM type 1 has a major impact on lens biometry. Furthermore, the difference in effect of DM types 1 and 2 on lens biometry may indicate a fundamental difference in pathogenesis. The decrease in equivalent refractive index of the lens seemed to compensate for the profound increase in lens convexity in patients with DM type 1, resulting in no significant change in lens power or ocular refraction with the duration of DM.

Refractive properties of the healthy human eye during acute hyperglycemia.

PURPOSE: To measure the refractive properties of the healthy human eye during acute hyperglycemia by means of Scheimpflug imaging and Hartmann-Shack aberrometry. METHODS: Acute hyperglycemia was induced in five healthy subjects (two males, three females, mean age +/-SD 24.8 years +/- 4.6) by means of an oral glucose tolerance test (OGTT) after subcutaneous somatostatin injection. Before and every 30 minutes after the OGTT, measurements with Scheimpflug imaging and Hartmann-Shack aberrometry were performed. The main outcome measures were the thickness and shape of the lens, and the ocular refractive error and higher order aberrations. The equivalent refractive index of the lens was calculated from these parameters. Measurements at baseline and during hyperglycemia were analyzed by means of Wilcoxon signed rank sum tests. RESULTS: During hyperglycemia (mean blood glucose level at baseline: 4.0 mmol/l; mean maximal blood glucose level: 18.4 mmol/l) no changes could be found in the refractive properties within the group. In one subject, a hyperopic shift (0.4 D) was observed, together with a more convex shape of the anterior lens surface and a decrease in the equivalent refractive index of the lens. CONCLUSIONS: This study shows that hyperglycemia generally does not cause changes in the refractive properties of the healthy eye. Nevertheless, in one subject a hyperopic shift accompanied by a change in shape and refractive index of the lens was measured. This finding could provide an explanation for the mechanism underlying the refractive changes that are often observed during hyperglycemia.