Central Cornea Thickness Research Articles

Consequences of Puberty on Efficacy of Intraocular Pressure-Lowering Drugs in Male Dutch-Belted Rabbits.

To investigate the changes in intraocular pressure (IOP), aqueous flow, and outflow facility, as well as efficacy of IOP-lowering drugs before and after sexual development in rabbits. Male Dutch-belted rabbits were studied at night between the ages of 8 and 44 weeks. During these times, body weight, testicular volume, and serum testosterone were measured to monitor sexual maturity. Ocular measurements included anterior chamber depth, central corneal thickness, IOP, aqueous flow, and outflow facility. Systemic acetazolamide or topical timolol, latanoprost, or saline were administered pre- and postpuberty to assess drug effects on these parameters. Body weight, testicular volume, and serum testosterone increased until 28 weeks of age. IOP increased during prepuberty (R2 = 0.49, P = 0.003), dropped significantly during puberty, rising again immediate postpuberty, and changing little thereafter. Postpuberty compared with prepuberty found higher IOP (P < 0.0001), slower aqueous flow (P = 0.008), lower outflow facility (not statistically significant, P = 0.07), increased central cornea thickness, and increased anterior chamber volume. Timolol lowered IOP both pre- and postpuberty, whereas, latanoprost and acetazolamide decreased IOP postpuberty only. As male rabbits mature, the cornea thickens and the anterior chamber volume increases. At the same time, aqueous flow slows, yet, IOP increases. This suggests that decreased outflow facility and/or increased episcleral venous pressure might contribute to the puberty-related changes in IOP. Underdevelopment of tissues of the outflow pathways may contribute to the differences in drug efficacy in rabbits when young compared with after sexual maturity.

Distribution and associations of intraocular pressure in 7- and 12-year-old Chinese children: The Anyang Childhood Eye Study.

PurposeTo report the intraocular pressure (IOP) and its association with myopia and other factors in 7 and 12-year-old Chinese children.MethodsAll children participating in the Anyang Childhood Eye Study underwent non-contact tonometry as well as measurement of central corneal thickness (CCT), axial length, cycloplegic auto-refraction, blood pressure, height and weight. A questionnaire was used to collect other relevant information. Univariable and multivariable analysis were performed to determine the associations of IOP.ResultsA total of 2760 7-year-old children (95.4%) and 2198 12-year-old children (97.0%) were included. The mean IOP was 13.5±3.1 mmHg in the younger cohort and 15.8±3.5 mmHg in older children (P<0.0001). On multivariable analysis, higher IOP in the younger cohort was associated with female gender (standardized regression coefficient [SRC], 0.11, P<0.0001), increasing central corneal thickness (SRC, 0.39, P<0.0001), myopia (SRC, 0.05, P = 0.03), deep anterior chamber (SRC, 0.07, P<0.01), smaller waist (SRC, 0.07, P<0.01) and increasing mean arterial pressure (SRC, 0.13, P<0.0001). In the older cohort, higher IOP was again associated with female gender (SRC, 0.16, P<0.0001), increasing central corneal thickness (SRC, 0.43, P<0.0001), deep anterior chamber (SRC, 0.09, P<0.01), higher body mass index (SRC, 0.07, P = 0.04) and with increasing mean arterial pressure (SRC, 0.09, P = 0.01), age at which reading commenced (SRC, 0.10, P<0.01) and birth method (SRC, 0.09, P = 0.01), but not with myopia (SRC, 0.09, P = 0.20).ConclusionIn Chinese children, higher IOP was associated with female gender, older age, thicker central cornea, deeper anterior chamber and higher mean arterial pressure. Higher body mass index, younger age at commencement of reading and being born of a caesarean section was also associated with higher IOP in adolescence.

Assessment of central corneal thickness, intraocular pressure and retinal nerve fiber layer thickness at women with polycystic ovary syndrome

Objective: To compare intraocular pressure, central cornea thickness, anterior chamber depth, axial length and thickness of retina nerve fiber layer between women with polycystic ovary syndrome and healthy at the same age segment. Methods: Between August 2015-January 2016, 46 with polycystic ovary syndrome and 53 healthy, were included. After performing refraction measurements, Intraocular pressure, central cornea thickness, anterior chamber depth, axial length and retina nerve fiber layer thickness were investigated . In the statistical analysis of the data, the Independent Samples t test was utilized in the comparison of groups. Results: While mean age was 23.43±4.52 (16-35) in the group with polycystic ovary syndrome, mean age level was found as 24.09±6.14 (18-41) among the controls (P=0,549). Intraocular pressure values were measured and found as 17.73±2.67 mmHg in the group with polycystic ovary syndrome, while the values were 15.21±2.42 mmHg in the controls (P <0,001) . Although it was 79.41±10.28 µm in the group with polycystic ovary syndrome, retina nerve fiber layer thickness in the nasal quadrant was found to be 73.83±10.98 µm among the controls. Conclusion: We found that the increased levels seen in intraocular pressure and retina nerve fiber layer thickness in the nasal quadrants of the patients with polycystic ovary syndrome were statistically significance. Hence, we recommend that the patients with polycystic ovary syndrome should be closely evaluated as to eye assessment.

Two Years’ Experience in Keratoconus Treatment using Collagen Cross-linking

ABSTRACT Purpose To evaluate safety, efficacy, and stability of cross-linking (CLX) procedure as a method for keratoconus treatment in the I and II stage of disease. Materials and methods Twenty eyes of 15 patients (13 males, 2 females, average age 31 years) with keratoconus I stage (13 eyes) and II stage (2 eyes) (by Krumeich classi­fication) were treated by CLX procedure, using riboflavin Medio Cross for standard CLX); riboflavin Medio Cross TE for transepithelial CLX was used to treat keratectasia after previous keratorefractive surgery; in all the cases UV CBM X linker (Vega, CSO) was used. The study included evaluation of uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA) pre- and postoperative, pachymetry (central cornea thickness) (Visante OCT, Zeiss) pre- and postoperative, total astigmatism pre- and postoperative, using keratotopography (Atlas, Zeiss). Diagnosis and analysis have been performed at the International Center for Ophthalmology in Moscow, Russian ­Federation, since 2012 to 2014 years. Follow-up period was from 1 to 24 months. Results Average UCVA preoperative was 0.4 (Decimal), and average BCVA was 0.64. Average UCVA postoperative was 0.49; average BCVA was 0.66. Total astigmatism preoperative was 2.81 D; total astigmatism postoperative 2.80 D. Central cornea thickness (CCT) preoperative 454 mkm; CCT post­operative 447 mkm. Conclusion Cross-linking indicated safety, stability, and efficacy for treatment of I and II stage keratoconus at the end of follow-up period. Cross-linking is not effective in the treatment of II and III stage of disease. Further study is required. How to cite this article Dementiev D, Sysoeva M, Shipunova A. Two Years’ Experience in Keratoconus Treatment using Collagen Cross-linking. Int J Kerat Ect Cor Dis 2017;6(1):11-13.

Corneal endothelial cell loss and corneal biomechanical characteristics after two-step sequential or combined phaco-vitrectomy surgery for idiopathic epiretinal membrane.

To assess the impact of sequential and combined surgery [cataract surgery and 23-gauge pars plana vitrectomy (PPV) with peeling] on corneal endothelium cell density (CED) and corneal biomechanical characteristics. Phakic eyes with epiretinal membrane (ERM) were prospectively allocated to (i) cataract surgery and subsequent PPV (CAT group), (ii) PPV and subsequent cataract surgery (VIT group) or (iii) phacovitrectomy (COMBI group). Eyes were examined at baseline, 1month after each surgery, and at 3 and 12months follow-up. Corneal endothelium cell density (CED) was assessed with non-contact specular microscopy. Pachymetry [central cornea thickness (CCT)], keratometry and cornea volume (CV) were measured with Pentacam Scheimpflug camera. Primary outcome was change in CED after 12months; secondary outcomes were changes in CCT and CV after 12months. Sixty-two eyes were enrolled and allocated to the three groups. The mean preoperative CED was 2776, 2794 and 2653 cells/mm2, which decreased significantly at 12months by 15.3, 20.0 and 19.3% in the CAT, VIT and COMBI group. There was no significant difference in percentage cell loss between the groups at final follow-up. The CED decreased significantly after cataract surgery, but was unaffected by PPV. Central cornea thickness (CCT) increased by 10μm (p=0.005) and CV by 1.38mm3 (2.3%, p<0.001) in the COMBI group. There were no significant differences in CCT or CV between the groups at final follow-up. Combined and sequential surgery in ERM leads to a small decrease in CED. Performing cataract surgery before, after or in combination with vitrectomy did not make any significant difference with respect to final CED, CCT or CV.

Characterization of ocular biometrics and aqueous humor dynamics in primary angle closure suspects.

Detailed characterizations of ocular biometrics and parameters of aqueous humor dynamics are lacking in primary angle closure suspect (PACS) patients. This study aims to characterize these parameters and compare them with age-matched healthy volunteers.Elderly healthy volunteers (60.6 ± 7.2 years of age, mean ± SD, n = 28) and PACS patients (64.1 ± 11.6 years, n = 30) completed the study. Parameters investigated were axial length (AXL), anterior chamber depth (ACD), anterior chamber volume (ACV), central cornea thickness (CCT), intraocular pressure (IOP), aqueous flow (Fa), outflow facility (C), episcleral venous pressure (EVP), and uveoscleral outflow (Fu). Comparisons and correlations were made between and within groups.In healthy volunteers, ocular biometric parameters, IOP, and EVP correlated very well between the 2 eyes of each individual, but Fa, C, and Fu were not significantly correlated. Biometric parameters of the PACS group significantly (P < 0.001) differed from those of the healthy controls: AXL (23.31 ± 1.03 mm [PACS] vs 22.39 ± 1.04 mm [Control]; mean ± SD), ACD (2.44 ± 0.33 mm [PACS] vs 1.86 ± 0.25 mm [Control]), ACV (136.0 ± 36.1 μL [PACS] vs 81.4 ± 21.8 μL [Control]), CCT (526.9 ± 37.0 μm [PACS] vs 556.1 ± 28.4 μm [Control]). There was no significant change in IOP, Fa, C, EVP, or Fu between Control and PACS. Furthermore, IOP showed no significant correlations with AXL, ACD, ACV, CCT, or C in both groups.The PACS eyes had a shorter AXL, a shallower ACD, and a smaller ACV, but a thicker CCT. Despite these morphological changes, the PACS eyes did not have any significant changes in IOP, and aqueous humor dynamics parameters. This is consistent with the findings that IOP did not show significant correlations with biometrics, or C.

Short-term effects of femtosecond laser assisted cataract surgery (FLACS) on central and peripheral cornea thickness

Short-term effects of femtosecond laser assisted cataract surgery (FLACS) on central and peripheral cornea thickness

A Comparison of Central Corneal Thicknesses Measured with Two Different Methods in Cases of Primary Open-Angle Glaucoma

ABSTRACTAccurate and repeatable measurement of the central cornea thickness (CCT) is important in terms of follow-up of glaucoma patients. The aim of this study was to compare CCT measurements made with an ultrasonic pachymeter (USP) and with the Spectralis Anterior Segment Module optical coherence tomography (OCT) device. The study included 52 eyes of 26 primary open-angle glaucoma patients. CCT measurements were taken with the USP device and then with the OCT by imaging cornea slices. The mean CCT was measured as 555.71 ± 47.76 μm with USP and 569.46 ± 49.5 μm with OCT. Despite the differences between the measurements of the two methods, a very strong degree of consistency was seen between the CCT measurement with USP and OCT (ICC = 0.93, p < 0.001).

Effect of femtosecond and microkeratome flaps creation on the cornea biomechanics during laser in situ keratomileusis: one year follow-up.

To compare the corneal biomechanical outcomes at one year after laser in situ keratomileusis (LASIK) with the flaps created by Ziemer and Moria M2 microkeratome with 110 head and -20 blade. Totally 100 eyes of 50 consecutive patients were enrolled in this prospective study and divided into two groups for corneal flaps created by ZiemerFemto LDV and Moria M2 microkeratome with 110 head and -20 blade. Corneal biomechanical properties including cornea resistance factor (CRF) and cornea hysteresis (CH) were measured before and 1, 3, 6, 12mo after surgery by ocular response analyzer. Central cornea thickness and corneal flap thickness were measured by optical coherence tomography. The ablation depth (P=0.693), residual corneal thickness (P=0.453), and postoperative corneal curvature (P=0.264) were not significant different between Ziemer group and Moria 110-20 group after surgery. The residual stromal bed thickness, corneal flap thickness, CH and CRF at 12mo after surgery were significant different between Ziemer group and Moria 110-20 group (P<0.01);Ziemer group gained better corneal biomechanical results. The CRF and CH increased gradually from 1 to 12mo after surgery in Ziemer group, increased from 1 to 6mo but decreased from 6 to 12mo in Moria 110-20 group. Both CRF and CH at one year after surgery increased with the increasing of residual cornea thickness; pre-LASIK CRF, CRF also increased with residual stromal bed thickness, while CH decreased with the increasing of pre-LASIK intraocular pressure and cornea flap thickness (P<0.01). In one year follow-up, femtosecond laser can provide better cornea flaps with stable cornea biomechanics than mechanical microkeratome.

Determinants of peripapillary retinal nerve fiber layer thickness regarding ocular and systemic parameters - the MIPH Eye&Health Study.

Optical coherence tomography (OCT) allows quantitative image analysis of retinal tissue in vivo. Peripapillary retinal nerve fiber layer (pRNFL) thickness is widely used for evaluation of retinal nerve fiber rarefaction in several optic neuropathies. This study evaluates associations of pRNFL thickness in healthy adult subjects in order to evaluate influencing factors. A cross-sectional study was performed in a working-age population. Only eyes without detectable ocular pathologies were included in the analysis. Among analyzed systemic cardiovascular parameters were age, gender, body-mass index, mean arterial blood pressure, HbA1c, high- and low-density-lipoproteins, and triglycerides. A comprehensive ophthalmological examination including refraction, tonometry, keratometry, and central corneal thickness measurmentwas performed. In addition, pRNFL thickness was imaged by spectral-domain OCT. Univariable and multivariable associations of pRNFL thickness in all four quadrants and on average with systemic and ocular parameters were calculated using a generalized estimating equation model. Three hundred and six subjects were included. pRNFL thickness measurements showed a significant association with spherical equivalent: pRNFL thickness decreased with increasing myopia in all quadrants (multivariable regression coefficients Beta: superior: 1.16, 95% CI [0.62;1.71], p < 0.001; temporal: 0.87, [0.33;1.41], p = 0.001; inferior: 1.80, [1.18;2.42], p < 0.001; nasal: 2.60, [2.01;3.20],p < 0.001) and on average (1.51, [1.20;1.82], p < 0.001). A thicker central cornea thickness was related to lower pRNFL in the superior (-0.05, [-0.10; -0.01], p = 0.01), the inferior quadrant (-0.05, [-0.10;0.00], p = 0.03) and on average (-0.04, [-0.07; -0.01], p = 0.02). All other parameters were not associated. Our findings highlight the importance of refraction when evaluating pRNFL thickness and its independence from other systemic parameters.

Changes in axial length, central cornea thickness, and anterior chamber depth after rhegmatogenous retinal detachment repair

BackgroundThis study was designed to measure changes in anterior chamber depth (ACD), central cornea thickness (CCT), and axial length (AL) after scleral buckle (SB) surgery or pars plana vitrectomy (PPV) for the repair of rhegmatogenous retinal detachment (RD).MethodsWe prospectively reviewed the records of 245 eyes of 245 patients scheduled to undergo SB surgery and 238 eyes of 238 patients scheduled to undergo PPV. ACD, CCT, and AL were measured by spectral-domain optical coherence tomography (SD-OCT) and biometry, before surgery as well as 6 and 12 months postoperatively.ResultsFor both SB and PPV surgeries, ACD was observed to decrease significantly postoperatively, with this trend continuing throughout the follow-up period (p < 0.005). CCT showed no significant difference after PPV or SB surgery. AL increased significantly after SB surgery but not PPV.ConclusionOur results show that SB surgery altered the shape of the eye by changing both ACD and AL. PPV resulted in altered ACD. These findings should elucidate the changes to be expected after SB and PPV surgeries.

Long-term evaluation of eyes with central corneal thickness

PurposeTo study long-term refractive and visual outcomes of laser in situ keratomileusis (LASIK) in eyes with a postoperative thin central cornea.MethodsIn this retrospective observational case series, we studied 282 myopic eyes with a normal preoperative topographic pattern and postoperative thin corneas (<400 μm) that had at least 3 years of follow-up after LASIK in three private clinics. The main outcome measures were safety, efficacy, predictability, percent tissue altered, and complications.ResultsThe mean postoperative central corneal thickness was 392.05 μm (range: 363.00–399.00 μm). After a mean follow-up of 6.89±2.35 years (standard deviation), the safety index was 1.17, the efficacy index was 0.94, and predictability (±1.00 diopter [D]) was 73.49. The mean residual stromal bed thickness was 317.34±13.75 μm (range: 275–356 μm), the mean flap thickness was 74.76±13.57 μm (range: 55–124 μm), and the mean percent tissue altered was 37.12%±3.62% (range: 27.25%–49.26%). No major complications were recorded.ConclusionLASIK with a resultant central cornea thickness <400 μm seems to be effective, safe, and predictable provided that preoperative topography is normal and the residual stromal bed thickness is >275 μm.

Visual Field Loss, Quality of Life and Ocular Biometric Parameters: A Cross Sectional Study of Taiwanese Adults

Purpose: To evaluate the severity of visual field loss in Taiwanese adults and assess the associations between visual field loss detected by frequency doubling technology (FDT) perimetry and vision-related quality of life (QoL) in Taiwanese adults. Methods: A total of 206 eyes from 206 subjects were included. Each subject was examined using FDT (N-30 threshold test) perimetry, optical coherence tomography (OCT), noncontact tonometry, cycloplegic refractometry, and National Eye Institute Visual Functioning Questionnaire 25 items (NEI VFQ-25). Results of FDT tests were classified into four groups (normal, early, moderate, and severe defects) using FDT probability map analysis. OCT parameters included central cornea thickness (CCT), thickness of retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), focal loss volume (FLV), and global loss volume (GLV) of GCC. The global score, subscales of near and distance activities of VFQ were calculated. Linear regression analysis was used to analyze the factors associated with visual field loss. Kruskal-Wallis analysis was used to examine the relationship between FDT results and vision-related QoL. Results: Among the 206 subjects, 72 were normal. The numbers of participants having early, moderate, and severe visual field loss were 101, 27, and 6. Moderate visual field defect was associated with CCT, GLV, GCC, and SE when compared to the subjects with normal response. Kruskal-Wallis analysis indicated that those with moderate visual field loss determined by FDT had worse vision related QoL and more difficulties in distance activities of VFQ (p=0.01) than people with normal response. Conclusion: Moderate visual field loss detected by FDT was associated with vision-related QoL in young adults. Further study is warranted to determine the potential of visual field loss as a predicting factor for vision loss related QoL.

Central Cornea Thickness in Glaucoma and Non-Glaucoma African Population

Central Cornea Thickness in Glaucoma and Non-Glaucoma African Population

Different Clinical Parameters to Diagnose Glaucoma Disease: A Review

Glaucoma is a severe human eye disease that causes permanent loss of vision. The main cause of glaucoma eye disease is the continuous loss of retinal nerve fiber layers due to the increase in the intra ocular pressure inside the eyes. The function of these retinal nerve fibers is the transformation of recognized object information in the form of signals to the brain, where these signals are recognized as object. Damages to these nerve fibers generate blind spots and these blind spots leads to permanent blindness. Therefore, Retinal Nerve Fiber Layer Thickness is the main parameter to diagnose glaucoma. Other parameters also leading to glaucoma are Intraocular Pressure, Vertical Cup to Disc Ratio, Neuro Retinal Rim Thickness, Central Cornea Thickness, Inferior Superior Nasal and Temporal Sector Ratio etc. Therefore, the identification of these parameters plays the major role in glaucoma assessment, since it allows timely treatment to prevent the vision loss caused by glaucoma. To estimate these parameters, clinical instruments such as Tonometry, Ophthalmoscopy, Heidelberg Retinal Tomography, Perimetry, Pachymetry, Optical Coherence Tomography, GDx etc are adopted. This paper presents the various parameters, as mentioned above, used to analyze and diagnose the Glaucoma disease and associated advantages, disadvantages and the different instruments used to analyze each clinical parameter. General Terms Glaucoma, Clinical Parameters

Central corneal thickness in children with type 1 diabetes mellitus and the effect of metabolic control on corneal thickness

Objective: To research whether central corneal thickness (CCT) of children with Type 1 diabetes mellitus (T1D) is different from healthy children at same age group and whether metabolic control has an effect on corneal thickness. Materials and methods: The children with T1D who applied to our outpatient department with the aim of controlling for possible diabetes complications and who had no diabetic retinopathy were prospectively evaluated. The healthy children from the same age group who applied to our outpatient setting for eye control and who had no systemic or eye disease were included in the control group. The CCT of all children was measured with ultrasonic pachymeter with topical anesthesia. Findings: While the corneal thickness for healthy children was 554.25±42.85 (500 – 678 µ), the average corneal thickness for diabetic children was 567.38±33.28 (487 – 628 µ). A significant difference was detected for average corneal thickness (Z=-2.040 p=0.041). No relation was detected between the central cornea thickness and the duration of diabetes (t=1.418 p=0.168), average HbA1C level (t=1.261p=0.218), hyperglycemia (t=0.228 p=0.821) and hypoglycemia attack number (t=-0.332 p=0.743). Result: CCT is increased in the patients compared to the control group even before diabetes mellitus (DM) has developed a retinopathy. A relation of this increase with period of diabetes, HbA1C level and hypoglycemia attack number could not be detected.

CD147 required for corneal endothelial lactate transport.

CD147/basigin is a chaperone for lactate:H(+) cotransporters (monocarboxylate transporters) MCT1 and MCT4. We tested the hypothesis that MCT1 and -4 in corneal endothelium contribute to lactate efflux from stroma to anterior chamber and that silencing CD147 expression would cause corneal edema. CD147 was silenced via small interfering ribonucleic acid (siRNA) transfection of rabbit corneas ex vivo and anterior chamber lenti-small hairpin RNA (shRNA) pseudovirus in vivo. CD147 and MCT expression was examined by Western blot, RT-PCR, and immunofluorescence. Functional effects were examined by measuring lactate-induced cell acidification, corneal lactate efflux, [lactate], central cornea thickness (CCT), and Azopt (a carbonic anhydrase inhibitor) sensitivity. In ex vivo corneas, 100 nM CD147 siRNA reduced CD147, MCT1, and MCT4 expression by 85%, 79%, and 73%, respectively, while MCT2 expression was unaffected. CD147 siRNA decreased lactate efflux from 3.9 ± 0.81 to 1.5 ± 0.37 nmol/min, increased corneal [lactate] from 19.28 ± 7.15 to 56.73 ± 8.97 nmol/mg, acidified endothelial cells (pHi = 6.83 ± 0.07 vs. 7.19 ± 0.09 in control), and slowed basolateral lactate-induced acidification from 0.0034 ± 0.0005 to 0.0012 ± 0.0005 pH/s, whereas apical acidification was unchanged. In vivo, CD147 shRNA increased CCT by 28.1 ± 0.9 μm at 28 days; Azopt increased CCT to 24.4 ± 3.12 vs. 12.0 ± 0.48 μm in control, and corneal [lactate] was 47.63 ± 6.29 nmol/mg in shCD147 corneas and 17.82 ± 4.93 nmol/mg in paired controls. CD147 is required for the expression of MCT1 and MCT4 in the corneal endothelium. Silencing CD147 slows lactate efflux, resulting in stromal lactate accumulation and corneal edema, consistent with lactate efflux as a significant component of the corneal endothelial pump.

Морфофункціональні зміни органа зору у зимівників української антарктичної станції «академік вернадський»

The study revealed that the Antarctic territory in the area of the Ukrainian Antarctic station "Academician Vernadsky" can be referred to the zone of the "super high", risk in developing ophthalmological pathology, caused by ultraviolet radiation. The results of the comprehensive dynamic study of 24 winterers of the XVI and XVII Ukrainian Antarctic expeditions (2011-2013) showed the developing of specific changes in the organ of vision under the exposure to the excessive natural ultraviolet radiation (UVR), such as parenchymatous-endothelial keratopathy, nuclear-posteriorcapsular phacopathy, maculopathy. Morphological changes were recorded using the cornea densitometry method: a decrease of the central cornea thickness by 14.3%, a decrease of the density and the number of endothelial cells of hexagonal type by 10.1% and 16.6%, respectively (P < 0.05). Using densitometry method, we detected morphological changes in the lens. Specifically, we found an increase of the optic lens density: in median zone by 10.1%, in maximal zone by 21.6%, in posterior part by 13.1%, P < 0.05. The results of densitometry recordings point to the development of local opacity in the posterior lens parts (in the nucleus and in the capsule). The data of the computed quantitative macula perimetry showed a significant decrease of light sensitivity of retina conicalis cells by 6 times (P < 0.05). The morphological signs of the endured acute solar retinopathy were found in more than 50% winterers. The revealed pathological changes can be considered as pre-, subclinical manifestations of the cornea dystrophy, cataracts and maculodystrophy, caused by specific action of the natural UVR, thus demanding the elaboration of the combined preventive measures.

Correlation between the pressure-to-cornea index and both structural and functional measures of glaucoma.

Purpose:the pressure-to-cornea index (PCI) was proposed in order to integrate intraocular pressure and central cornea thickness as a single-risk factor for glaucoma. The purpose of this study was to correlate the PCI with a structural and two functional measures of glaucoma.Setting:University Hospital in South America.Materials and Methods:Pressure-to-cornea index was calculated for 70 eyes of 36 subjects (glaucoma and suspects). Cup-to-disc (C/D) ratio, mean deviation (MD) and pattern standard deviation (PSD) as recorded by Humphrey automated perimetry (SITA 24-2) were correlated with PCI (Pearson's correlation coefficient).Results:Pearson's correlation coefficient between PCI and C/D was 0.329 (95% confidence interval [95% CI], 0.09–0.526; P = 0.006); between PCI and MD was − 0.356 MD (95% CI, −0.549 to − 0.126; P = 0.003); and between PCI and PSD was − 0.215 (95% CI, −0.433 to 0.025; P = 0.07).Conclusion:In addition to serve as a single-risk factor, PCI can be used to stage glaucoma severity as well.

Sensitivity of the Risk Factors for the Progression of Ocular Hypertension to Primary Open Angle Glaucoma

In this article we evaluate the sensitivity of the risk factors of ocular hypertension progression in primary open angle glaucoma in order to distinguish between the three risk levels based on prediction classification models. The prediction classification models were trained and testing by using the most common risk factors from examination of 398 Egyptian patients. Standard classification trees as well as bagged classification were used. We classify the risk level into three risk levels which are high, middle and low based on the combination of the structural and functional risk factors. The classification outcomes of the trees were compared and we measured the sensitivity of each risk factor. The bagged classification has the best accuracy which is 87.7% for training datasets and 72.2% for testing datasets with area under the receiver operating characteristics curve (AUROC) 0.925 while decision tree gave 80% for training datasets and 68.7% for testing datasets with AUROC 0.868. The central cornea thickness (CCT) gave the best with average AUROC 0.946. Bagged classification tree promises to be a new and efficient approach for glaucoma classification. The CCT is very important risk factor due to its classification sensitivity.