Duarte Amado’s research while affiliated with Centro Hospitalar Universitário de Lisboa Central and other places

Purpose Chronic hyperglycemia is responsible for vascular and neurodegenerative retinal changes in diabetic patients. However, other eye structures have been also associated with changes, such as corneal biomechanics and lens thickness. The author's objective was to analyze the accommodative process – crystalline structural change and pupillary diameter based on Anterior Segment Optical Coherence Tomography (AS-OCT). Methods Prospective case-control study. The anterior chamber parameters were studied using AS-OCT. The monocular accommodative process was obtained with different Dioptric Powers (0 D, 2.5 D, 5 D and 7 D – lens integrated in the OCT software) in both controlled photopic and scotopic conditions. 2 groups have been analyzed: group 1 with type 2 diabetic patients and group 2 with healthy-controls. Measurements of anterior chamber depth (ACD), lens vault (LV), pupillary diameter (PD) and iris thickness (IT) were obtained. Results A total of 71 patients were evaluated (group 1 − n = 36; group 2 – n = 35). The mean age was 69.15 ± 5.55 years. Diabetic patients have showed the basal highest LV and lowest ACD values, with statistically significance (p < 0.05). In highest accommodative power, group 2 has experimented a significant reduction in ACD, ACA and PD (p < 0.05). The LV change has not proved important in the process. Group 1 has showed a significant response in scotopic conditions, even with a lower response with the highest accommodative stimuli compared to group 2. Conclusions The accommodative process is impaired in diabetic patients, with a significant difference in pupillary response more than in lens vault. This could be important to explain the importance of the anterior segment of crystalline in accommodation. Further studies will be necessary to clarify the DM effects on these parameters.

The purpose of this study is to evaluate the macular ganglion cell layer (GCL) and peripapillary retinal nerve fibre layer (RNFL) thickness in patients with unilateral posterior cerebral artery (PCA) ischaemic lesions using spectral-domain optical coherence tomography (SD-OCT). A prospective, case-control study of patients with unilateral PCA lesion was conducted in the neuro-ophthalmology clinic of Centro Hospitalar Lisboa Central. Macular and peripapillary SD-OCT scans were performed in both eyes of each patient. Twelve patients with PCA lesions (stroke group) and 12 healthy normal controls were included in this study. Peripapillary RNFL comparison between both eyes of the same subject in the stroke group found a thinning in the superior-temporal (p = 0.008) and inferior-temporal (p = 0.023) sectors of the ipsilateral eye and nasal sector (p = 0.003) of the contralateral eye. Macular GCL thickness comparison showed a reduction temporally in the ipsilateral eye (p = 0.004) and nasally in the contralateral eye (p = 0.002). Peripapillary RNFL thickness was significantly reduced in both eyes of patients with PCA compared with controls, affecting all sectors in the contralateral eye and predominantly temporal sectors in the ipsilateral eye. A statistically significant decrease in macular GCL thickness was found in both hemiretinas of both eyes of stroke patients when compared with controls (p < 0.05). This study shows that TRD may play a role in the physiopathology of lesions of the posterior visual pathway.

Glaucoma is a multifactorial condition under serious influence of many risk factors. The role of diabetes mellitus (DM) in glaucoma etiology or progression remains inconclusive. Although, the diabetic patients have different healing mechanism comparing to the general population and it has a possible-negative role on surgical outcomes. This review article attempts to analyze the association of both diseases, glaucoma and DM, before and after the surgery. The epidemiological studies, based mainly in population prevalence analyzes, have shown opposite outcomes in time and even in the most recent articles also the association remains inconclusive. On the contrary, the experimental models based on animal induced chronic hyperglycemia have shown an important association of both diseases, explained by common neurodegenerative mechanisms. Diabetic patients have a different wound healing process in the eye viz-a-viz other organs. The healing process is more and it results in lower surgical survival time, higher intraocular pressure (IOP) levels and, therefore, these patients usually need more medication to lower the IOP. Both randomized and nonrandomized retrospective and experimental molecular studies have shown the association between DM and glaucoma. Further studies are needed to get better explanations about outcomes on more recent surgical procedures and with the exponential use of antifibrotics. How to cite this article: Costa L, Cunha JP, Amado D, Pinto LA, Ferreira J. Diabetes Mellitus as a Risk Factor in Glaucoma’s Physiopathology and Surgical Survival Time: A Literature Review. J Curr Glaucoma Pract 2015;9(3):81-85.

Purpose Diabetes Mellitus is associated with changes in refractive parameters. Some aspects already studied were the corneal biomechanics and lens thickness. Although, the discussion about anterior chamber angle and depth is still open. The author objective was to analyze and correlate the anterior chamber depth, lens vault and lens thickness with disease duration and metabolic status. Methods Prospective case‐control study. The anterior chamber and refractive parameters were studied using the Visante OCT and the differences between diabetic patients with metabolic control and disease stability were determined (group 1), without (group 2) and group‐control (3). The metabolic control is based on HbA1c levels. The cut‐off considered was 7%. Results A total of 64 patients were evaluated (group 1 – n = 21; group 2 – n = 20; group 3 – n = 23). The mean age was 64.32 ± 7.55 years and approximately 5 years of disease duration. In both groups of diabetic patients we found thicker lens, narrow anterior chamber and higher lens vault compared to control group. There was a difference between diabetic groups exists, but it was not statistically significant. Conclusions The anterior chamber angle and lens vault are influenced by the serum glucose levels. Further studies will be necessary to clarify the physiopathology mechanism responsible for the anterior segment modifications.

Purpose Diabetes Mellitus is associated with changes in refractive parameters. Some aspects already studied were the corneal biomechanics and lens thickness. Although, the discussion about anterior chamber angle and depth is still open. The author objective was to analyze and correlate the anterior chamber depth, lens vault and lens thickness with disease duration and metabolic status. Methods Prospective case–control study. The anterior chamber and refractive parameters were studied using the Visante OCT and the differences between diabetic patients with metabolic control and disease stability were determined (group 1), without (group 2) and group‐control (3). The metabolic control is based on HbA1c levels. The cut‐off considered was 7%. Results A total of 64 patients were evaluated (group 1 – n = 21; group 2 – n = 20; group 3 – n = 23). The mean age was 64.32 ± 7.55 years and approximately 5 years of disease duration. In both groups of diabetic patients we found thicker lens, narrow anterior chamber and higher lens vault compared to control group. There was a difference between diabetic groups exists, but it was not statistically significant. Conclusions The anterior chamber angle and lens vault are influenced by the serum glucose levels. Further studies will be necessary to clarify the physiopathology mechanism responsible for the anterior segment modifications.

Purpose The authors intend to present an analysis and comparison of the choroidal thickness in more distant superior regions. Choroidal thickness is increased in a heterogeneous pattern superiorly to the fovea in diabetic patients without diabetic retinopathy. Methods Observational case‐control study of 60 eyes of 60 patients with diabetes mellitus type 2 without diabetic retinopathy. A control group of 31 eyes of 31 patients without diabetes with similar demographic features was also created. All the patients were recruited from the same outpatient clinic. Enhanced depth imaging spectral‐domain optical coherence tomography ( EDI SD ‐ OCT SPECTRALIS ® ) was performed and high‐resolution macular scans were obtained. Choroidal thickness was evaluated 2000 μ m superiorly to the fovea by manual layer segmentation. Previous studies have validated the validity of using a manual layer segmentation procedure in OCT . Statistical analysis was done with SPSS Statistics. A p value <0.05 was considered statistically significant. Results Diabetic patients were in average 67.0 ± 9.6 years old and 56.7% were male. Average choroidal thickness 2000 μ m superiorly to the fovea was 287.77 ± 74.32 μ m in diabetic patients and 249.81 ± 53.96 μ m in non‐diabetic patients. There was a significant increase in choroidal thickness in diabetic patients when compared to non‐diabetic patients (T‐student, p = 0.014). Conclusions Choroidal thickness can be accurately measured using high‐definition macular OCT scans. This study documented structural differences in the choroid associated with diabetes mellitus type 2 that are not only present in the central foveal area as reported in previous studies. Diabetes Mellitus is associated with multiple microvascular dysfunctions that are probably coupled with choroidal vascular modifications that induce changes in thickness.

Purpose Historically, is made the distinction between optic neuropathies and macular diseases. Although, in our practical experience we believe that optic nerve ( ON ) damage, such as nerve edema or atrophy, at certain point will affect the macula. We have analyzed the scientific/structural impact of this clinical impression. The authors studied the correlation between Retinal Nerve Fiber Layer ( RNFL ) thickness and total macular/ganglionic cell layer ( GCL ) thicknesses using Optic Coherence Tomography (Heidelberg Spectralis ® ). Methods This retrospective study, evaluate 114 patients with the initial diagnose of optic neuropathy. First, was measured the average thickness of RNFL in 4 quadrants and the central macula and GCL thicknesses in 1º, 2º and 3º mm in fovea. We studied it in 3 groups: ON pathology (1º – n: 68), chiasmal compressive lesions (2º – n: 8) and retro‐chiasmal pathology (3º – n: 38). The layer's thickness was correlated in 3 groups. Results The 1º and 3º group had a significant impairment in all measures ( RNFL , total central macula and GCL ). There is a moderate correlation between RNFL and total central macular thicknesses (r: 0,354 and r: 0,314) and the correlation is strong comparing RNFL and GCL in 2º mm (r: 0,653 and r: 0.775) and 3º mm (r: 0,674 and r: 0, 839) thicknesses. Although, we didn't find any correlation between the RNFL and GCL thicknesses in 1º mm of fovea. In 2º group the results wasn't statistically significant, possible because the sample is short (n: 8). Conclusions In both groups, there is a correlation between the RNFL and total macula thicknesses. The impairment of total macula thickness is strongly correlated with the decreased thickness in GCL of foveae's 2º and 3º mm. This study shows in that pré‐chiasmal and retrochiasmal lesions, the impairment RNFL co‐exists with affection of macula thickness.

Purpose To evaluate the thickness of macular retina and determine which retinal layers are most affected by retrochiasmal visual pathways lesions. Methods Mean retinal thickness utilizing automated intraretinal layer segmentation of spectral domain optical coherence tomography scans was performed in 40 eyes of 40 patients with retrochiasmal visual pathways lesions and compared with 60 eyes of control subjects. Multiple linear regression analysis was used to determine the relationship between retinal thickness and follow‐up, age and gender. Results Ganglion cell and inner plexiform layer was thinner in the temporal hemiretina ipsilateral and in the nasal hemiretina contralateral than in healthy controls. The mean thickness was significantly reduced in lesions over 6 months of duration, with no differences in correlations with age or gender. Conclusions This study demonstrate ganglion cell and inner plexiform thinning in the hemimacular area. These results support the concept that transneuronal retrograde degeneration of the retinal ganglion cells can be detected by OCT in humans with retrochiasmal visual pathways lesions. This homonymous hemimacular thinning in OCT represents an imaging biomarker that can be of valu in diagnosis, prognosis and clinical trials of neuroprotectives therapies.

Purpose: The authors present a comparative study of corneal sensitivity in patients with diabetes mellitus type 2. Methods: Transverse observational study of 40 eyes of 40 diabetic patients. Corneal sensitivity was measured by esthesiometry using a handheld esthesiometer (Cochet-Bonnet). The measurements were performed in 4 quadrants: superior, temporal, inferior, nasal. The procedure was repeated three times. Patients were also divided between those with or without diabetic retinopathy. A control group of 40 eyes of 40 non-diabetic patients was also created. Corneal confocal microscopy (Heidelberg®) was also performed and results were compared. Results: Patients were in average 60 years old. Gender distribution was simi- lar. Esthesiometry was different between the diabetic patients and the control group (p<0.05). Diabetes Mellitus was associated with corneal hypoesthesia. Moreover the hypoesthesia was more severe in the patients with diabetic retinopathy when compared with those with diabetes without retinopathy. Imaging with corneal confocal microscopy also detected several differences between diabetic and non-diabetic patients. Conclusion: Corneal sensitivity is significantly reduced in diabetic patients. Systemic peripheral neurodegeneration present in Diabetes Mellitus also affects corneal enervation. Further studies are needed to further understand the underlying mechanisms speci cally associated with neurodegeneration of these nerves. The role of esthesiometry in the diabetic retinopathy screening needs to be explored.