Wide-field choroidal thickness and vascularity index in myopes and emmetropes.

PURPOSE: To study regional variations in choroidal thickness (CT), luminal thickness and stromal thickness of the choroid, and choroidal vascularity index (CVI) in low myopic and emmetropic eyes using wide-field optical coherence tomography (OCT). METHODS: Sixty-nine healthy young adults between 20 and 38 years of age participated in this study, including 40 low myopes (mean ± SD spherical equivalent (MSE) refractive error: -3.00 ± 1.39 D, range: -6.00 to -0.62 D) and 29 emmetropes (MSE: -0.05 ± 0.09 D, range: -0.25 to +0.12 D). Wide-field CT, luminal thickness, stromal thickness and CVI were measured across five eccentricities (fovea, parafovea, perifovea; near-periphery and periphery) and four quadrants (nasal, temporal, inferior and superior), in vertical and horizontal meridians, while controlling for a range of extraneous factors potentially influencing the CT. Custom-written software was used to segment and binarize the OCT images. RESULTS: Wide-field CT, luminal thickness and stromal thickness, averaged across all participants, exhibited significant topographical variation, with the foveal (379 ± 8 µm, 200 ± 4 µm, 179 ± 4 µm, respectively) and peripheral (275 ± 8 µm, 161 ± 4 µm, 114 ± 4 µm, respectively) regions presenting the thickest and thinnest regions (all p < 0.001). Wide-field CVI showed a progressively higher percentage (greater vascularity) with increasing eccentricity from the fovea towards the periphery (p < 0.001). Macular CT and stromal choroidal thickness were significantly thinner in myopes compared to emmetropes (p < 0.05). Myopes (55.7 ± 0.3%) showed a slightly higher CVI compared with emmetropes (54.4 ± 0.4%) (p < 0.05). CONCLUSIONS: Low myopia in young adults was associated with significant choroidal thinning across the macular, but not extramacular regions, with this decrease in choroidal thickness mostly attributed to thinning in the stromal component of the choroid, rather than the luminal (vascular) component.

The effect of trabeculectomy on contrast sensitivity, corneal topography and aberrations.

PURPOSE: To investigate the effect of trabeculectomy on corneal topography, corneal sensitivity and aberrations. METHODS: Twenty-four eyes of 24 subjects with open-angle glaucoma who required glaucoma filtration surgery were assessed. The evaluation of corneal topography, corneal sensitivity and aberrations were done before the trabeculectomy procedure, 1 week and 1 month after the trabeculectomy. RESULTS: There were significant differences in cylindrical power (P = 0.02), contrast sensitivity at 12 cycle/degree spatial frequency (P = 0.04) as well as high order aberration (P = 0.04) and high order without spherical component (P = 0.02) following trabeculectomy. However, significant differences were found for keratometric results and Fourier index in 3 and 6 mm pupil diameters between pre- and post-trabeculectomy (P > 0.05). CONCLUSIONS: According to the findings of the current study, trabeculectomy affects contrast sensitivity at 12 cycle/degree spatial frequency, higher-order aberration and higher order without spherical component aberration 1 month after trabeculectomy. Being knowledgeable about these changes may lead to some advancement in post-surgical management of patients particularly in early stages following trabeculectomy.

Topographic determination of corneal asphericity as a function of age, gender, and refractive error.

The aim of the study is to evaluate corneal asphericity in three diameters of 5, 6, and 7 mm, and to assess the effect of age, refractive error, and gender on asphericity. The study included 500 healthy subjects with a mean ± SD age of 29.51 ± 11.53 years. All analyses were based on the right eyes of the patients. Topographic data were analyzed using Oculus Keratograph 4. Mean ± SD corneal asphericity values of the study population in 5, 6, and 7 mm diameters were -0.21 ± 0.11, -0.24 ± 0.10, and -0.27 ± 0.11, respectively. The anterior corneal surface asphericity showed no correlation with either age, gender, or refractive error. The corneal asphericity shows a tendency for an increase with diameter and asphericity does not have a significant correlation with any factors of age, gender, and refractive error.

Optical Coherence Tomography and Biometry in High Myopia with Tilted Disc.

PURPOSE: The purpose of this study was to compare retinal thickness and biometric parameters between highly myopic eyes with and without tilted optic discs. METHODS: A total of 60 eyes from 60 highly myopic individuals (defined as a mean spherical equivalent refraction of -6.00 D or greater and axial length ≥26 mm) underwent detailed ophthalmic examination. Twenty-one eyes (13 females and 8 males; mean age: 29 ± 7 years) with tilted optic discs were recruited and compared with 39 eyes (23 females and 16 males; mean age: 28 ± 6 years) of control subjects without tilted optic discs using spectral domain optical coherence tomography (OCT) and the Lenstar biometer. Disc ovality was assessed using the ratio of minimum to maximum disc diameter (index of tilt). A ratio of ≤0.80 was considered as a tilted optic disc. RESULTS: There were no significant differences in biometric parameters between two groups. However, myopia in the tilted disc group was significantly greater compared to the non-tilted group (-8.82 ± 1.58 D vs. -7.84 ± 1.22 D, p = 0.01). Comparison of OCT sectoral macular nerve fiber layer measurements between groups showed significant differences in inner ring thicknesses for the nasal (p = 0.01), inferior (p < 0.001), and temporal (p = 0.04) quadrants. A significant difference was also seen in outer ring macular nerve fiber layer thickness for the temporal quadrant (p = 0.03). No significant differences were demonstrated in optic disc peripapillary retinal nerve fiber layer (RNFL) thickness between the two groups. CONCLUSIONS: Mean spherical equivalent refractive error is strongly correlated with optic disc tilt; however, other biometric factors are independent of tilt. Structural examination of the eye using OCT can be employed to differentiate between eyes with tilted optic discs and those with normal discs. Peripapillary RNFL appears to be unaffected by tilted discs.

Effect of topical diclofenac on postoperative photorefractive keratectomy pain: a randomized, controlled trial.

BACKGROUND: A major disadvantage of photorefractive keratectomy is postoperative pain and discomfort. This study aims to evaluate whether topical diclofenac 0.1% therapy adds any extra benefit to systemic diclofenac in controlling pain after photorefractive keratectomy. DESIGN: Prospective randomized, double-masked clinical trial applied in the Khatam-al-Anbia Eye Hospital, Mashhad University of Medical Sciences, Mashhad, Iran. PARTICIPANTS: Sixty-eight individuals (age range, 18-35 years) having bilateral photorefractive keratectomy for myopic correction with or without astigmatism. METHODS: All patients received 100 mg of extended-release oral diclofenac two times (12-h interval) before photorefractive keratectomy surgery. Postoperatively, patients were randomized into the case and control groups. Case group was administered the diclofenac 0.1% drop, one drop 2 h preoperatively and four times daily postoperatively for 3 days, whereas the control group was given artificial tears instead. MAIN OUTCOME MEASURES: Pain level, photophobia and functional activity were evaluated by the patient after operation. RESULTS: Two days after surgery, no statistically significant difference in pain level was noted between both groups. In addition, photophobia and functional activity was not different between the case and control groups. Eyelid oedema and conjunctival injection levels were significantly higher in the control group (P < 0.001). CONCLUSIONS: Administration of topical diclofenac to a standardized postoperative pain regime did not alleviate post-photorefractive keratectomy pain, although it is effective in local signs like eyelid oedema and conjunctival injection. It can be concluded that oral diclofenac is sufficient in the management of post-photorefractive keratectomy pain and addition of the topical diclofenac is unnecessary.

Ophthalmic complications among cases of head trauma in north-eastern Iran.

The aim of this study was to investigate the prevalence and pattern of ocular complications in patients with head trauma admitted to the main trauma centre in north-eastern Iran. A total of 459 head-injured patients (36.56 ± 19.30 years of age) with at least one ocular manifestation were recruited. Each individual patient was examined by a neurosurgeon and an ophthalmologist to confirm the type of ocular complication. In addition, all patients were analysed for age, gender, and cause of head injury in addition to the ophthalmic and neurosurgical examinations. Of the 459 patients, 142 (31 %) were female and 317 (69 %) were male. The maximum rate of ocular complications was during the third decade of life and minimum during childhood and in the elderly (>71 years) population. The leading cause of head trauma was motor vehicle accidents, predominant in male adults aged 21-40 years. Ocular complications observed were classified into three major groups: soft-tissue injuries to the globe and adnexae (n = 434), orbital complications (n = 45) and neuro-ophthalmic complications (n = 152). In conclusion, our data provides a useful estimation of the rate and pattern of ocular complications among patients with head injuries seen in trauma centres in north-eastern Iran. Understanding the pattern of ocular complications helps us to design more appropriate preventive methods.

Off-axis partial coherence interferometry in myopes and emmetropes.

PURPOSE: This study describes the axial and peripheral dimensions of myopic and emmetropic eyes in a wide range of retinal locations using a non-contact optical biometer (Zeiss IOLMaster) based upon the principle of partial coherence interferometry. Understanding the optical properties of the peripheral eye may provide insight into myopia development and the possible effects on off-axis visual performance. METHODS: Fifty-two myopes (spherical equivalent between -2.00 and -9.62 D) and 27 emmetropes (spherical equivalent between -0.50 and +0.50 D) with astigmatism less than 0.75 D, participated in this study. Axial length and peripheral cornea to retina lengths were measured using partial coherence interferometry at the fovea and up to ± 30° eccentricity along the horizontal and vertical meridian in 10° steps. Relative cornea to retina length was calculated by subtracting the axial length from that obtained at each peripheral location. RESULTS: Our results showed significant differences between refractive groups for both horizontal (p < 0.001) and vertical (p < 0.001) meridians, illustrating that the retinal shape profile is significantly different between myopes and emmetropes. Myopic eyes exhibited a greater rate of change in cornea to retina lengths with increasing eccentricity than emmetropic eyes, with the temporal portion of the retina exhibiting the steepest shift. In addition, significant nasal-temporal asymmetry was observed, which was more pronounced in myopic eyes. CONCLUSIONS: Axial and peripheral cornea to retina dimension measurements, using partial coherence interferometry, suggest that myopic eyes tend toward an ellipsoid shape compared to the spherical emmetropic eyes.

Comparison of Visual Field Measurements in Glaucomatous Eyes using Oculus and Metrovision Perimeters.

Purpose: To investigate the agreement between the Oculus and Metrovision perimeters in the visual field evaluation of glaucoma patients. Methods: In this cross-sectional study, 41 consecutive glaucoma patients were enrolled. After detailed clinical examinations, visual field testing was performed for all patients using the Oculus and Metrovision perimeters. The interval time between the two visual field examinations was 30 min. Results: A total of 22 participants were male (53.7%) and the mean ± standard deviation (SD) age was 58.6 ± 9.1 years. The absolute average of the mean deviation (MD) in the oculus perimeter (8.24 ± 4.92 dB) was higher compared to the Metrovision perimeter (4.02 ± 4.62; P < 0.001). This difference was also evident in the Bland-Altman graph. The loss variance (pattern SD) values of Oculus perimeter (28.58 ± 16.40) and Metrovision perimeter (28.10 ± 28.45) were not significantly different; although based on the Bland-Altman plots in the lower MDs, the agreement is better and the data dispersion is lower, and in the higher MDs, the agreement is lower. The parameters of four visual field quadrants were also compared and showed poor correlations (P < 0.001). Conclusion: The Oculus and Metrovision perimeter devices have good agreement in lower MDs; however, they cannot be used interchangeably.

Comparison of corneal biomechanical properties in healthy thin corneas with matched keratoconus eyes.

PURPOSE: To compare corneal biomechanical parameters of normal thin corneas with matched keratoconus eyes. SETTING: Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. DESIGN: Cross-sectional comparative study. METHODS: Dynamic corneal response parameters of Corvis ST were compared in 61 eyes with keratoconus with 61 matched healthy thin corneas (corneal thinnest point <500 µm), while corneal thickness, biomechanically corrected intraocular pressure, and age were considered covariates. The receiving operator sensitivity curve analysis was used to determine the cutoff point with the highest sensitivity and specificity, and the area under the curve (AUC) for each parameter. RESULTS: All biomechanical parameters were statistically significant between the 2 groups except for the first ( P = .947) and second ( P = .582) applanation length, first ( P = .783) and second ( P = .301) applanation velocity, and deformation amplitude in the highest concavity phase ( P = .106). The highest mean difference between groups (12.89 ± 2.03 mm Hg/mm) was related to the stiffness parameter at the first applanation (SPA1). Although the Corvis biomechanical index and tomographic biomechanical index had the highest detection ability based on their AUC (0.912 and 0.959, respectively), among the standard and combined biomechanical parameters except for keratoconus screening parameters, the highest discriminative ability was related to SPA1 with AUC, sensitivity, and specificity of 0.793, 60.66%, and 90.16%, respectively. CONCLUSIONS: Keratoconus corneas were significantly softer compared with healthy thin corneas of matched thickness. Optimal cutoff points close to the maximum value defined for screening parameters limit their clinical use for differentiation purposes in these particular types of cases.

After-effect on tear film quality and quantity of reading on laptop computer screen versus hardcopy.

CLINICAL RELEVANCE: Electronic displays, including laptops, tablets, and smartphones, have dramatically altered the way information is accessed and become significant factors in human daily life. They interfere with the blink rate and increase dry eye symptoms, which lead to more discomfort compared to hard copy while reading. BACKGROUND: Digital eye strain occurs when an individual suffers from symptoms, or they are exacerbated, while performing a task requiring digital screen viewing. This study assessed the tear film status immediately following reading on a laptop computer screen versus an identical hard copy. METHODS: Thirty young adults with normal ocular health and reporting no significant symptoms of dry eye (ocular surface disease index (OSDI) score < 13 and non-invasive tear break-up time (NITBUT) > 10 seconds) read a text as hard copy and on a laptop computer screen for 30 min on separate days in a random sequence in a controlled reading experimental condition. The texts were matched in size and contrast and presented at a viewing distance of 40 cm. The NITBUT and strip meniscometry tube tests were administered at baseline and after reading in both conditions. RESULTS: The median baseline NITBUT decreased from 13.0 s to 10.0 s (P < 0.001) after hardcopy reading and to 7.0 (P < 0.001) after reading from a laptop computer screen, with a significant difference between the task medium (P = 0.001). The baseline strip meniscometry tube results decreased from 6.7 mm to 5.0 mm (P < 0.001) after hardcopy reading and to 5.0 mm (P < 0.001) after reading from a laptop computer screen, but there was no significant difference with the task medium (P = 0.085). CONCLUSION: Reading in both conditions led to tear film instability in terms of the tear film quality and quantity. Additionally, the computer screen has a greater impact on the TBUT compared to hardcopy reading, while these two reading mediums had a similar effect on the tear volume.

Seasonal variations in anterior segment angle parameters in myopes and emmetropes.

CLINICAL RELEVANCE: Seasonal variations are known to occur in a range of ocular parameters and in conditions including refractive error and glaucoma. It is of clinical importance to know if seasonal changes also occur in anterior segment angle parameters, given that they can influence these conditions. BACKGROUND: The study aimed to examine the seasonal variations in anterior segment angle parameters in healthy young adults. METHODS: Twenty-three emmetropic participants with a mean age of 26.17 ± 4.43 years and 22 myopic participants with a mean age of 27.27 ± 4.47 years completed four seasons of data collection. Anterior segment angle parameters were measured using swept-source anterior segment optical coherence tomography. Intraocular pressure (IOP) and objective refraction were also measured. Repeated-measures analysis of variance was used to determine the effect of season and refractive error on the various ocular parameters. RESULTS: A significant main effect of season was found for the majority of anterior segment angle parameters, including the angle opening distance at 500 and 750 µm from the scleral spur (p = 0.02, p = 0.006, respectively), angle recess area at 500 and 750 µm from the scleral spur (both p = 0.002), and trabecular iris space area at 500 and 750 µm from the scleral (p = 0.02, p = 0.008, respectively). However, measures of anterior chamber depth and trabecular iris angle did not exhibit statistically significant seasonal variations (all p > 0.05). A significant main effect of season was also found for the changes in IOP (p = 0.004) and objective refraction (p < 0.001). There was no season by refractive group interaction for any anterior segment angle parameter or IOP (all p > 0.05). CONCLUSION: There is a small but significant seasonal changes in the anterior segment angle parameters, refractive error, and IOP in healthy young adult males, in which the anterior segment angle dimensions are narrower, the IOP is higher, and the refraction is more myopic during winter.

Efficacy of five-flash intense pulsed light therapy technique in patients with meibomian gland dysfunction.

CLINICAL RELEVANCE: Meibomian gland dysfunction is the main cause of evaporative dry eye disease and can lead to ocular discomfort and ocular surface damage. Early diagnosis and management of this condition can prevent its impact on patients 'visual health and quality of life. BACKGROUND: In the last decade, intense pulsed light therapy (IPL) has been introduced as a therapeutic option for patients with meibomian gland dysfunction (MGD). Various treatment modalities and protocols have been reported to increase the efficacy of this technique. This study aimed to assess the efficacy of a novel five-flash IPL technique in combination with home-based therapy and to compare it with conventional home care alone in patients with MGD. METHODS: In a randomised controlled trial, 100 symptomatic MGD patients were enrolled. The treatment group underwent three sessions of a five-flash IPL therapy. For all participants, eyelid warming, lid hygiene and lubricant therapy was prescribed. Ocular surface parameters were compared for control and treatment groups. RESULTS: Ocular Surface Disease Index (OSDI), non-invasive keratograph tear break up time (NIKBUT), fluorescein TBUT, MG expressibility, meibum quality and tear osmolarity were improved at follow up visits in both groups (p < 0.05). On day 75, NIKBUT was significantly higher in the IPL group (p = 0.045). The IPL treatment effect was not statistically significant (p > 0.05), except for bulbar and limbal hyperaemia (p = 0.02 and p = 0.02). In both groups, younger patients showed more improvement in NIKBUT (p = 0.02, r = -0.32; p < 0.001, r = -0.52). CONCLUSION: IPL therapy combined with conventional home-based therapy, and home care alone are both effective for patients with MGD. IPL may have an additional role in the improvement of ocular hyperaemia.

The effect of instrument alignment on peripheral refraction measurements by automated optometer.

PURPOSE: Interest in peripheral refraction measurement has grown in recent years in response to the insight it may provide into myopia development. In light of the likely increase in the clinical use of open-field autorefractors for peripheral refraction measurements, the question of instrument alignment and its impact on the accuracy of refraction measurements is raised. The aim of this study was to investigate the accuracy and precision when an open-field device was moved away from alignment with the corneal reflex towards the pupil margins, and to determine the optimum alignment position for peripheral refraction measurements. METHODS: Autorefractions were performed on the right eyes of 10 healthy participants using the Shin-Nippon NVision-K 5001 autorefractor. At least five measurements were taken with the subject fixating a distance target in the primary position of gaze, and then four peripheral fixation targets located along the horizontal meridian (10° and 20° eccentricities in the nasal and temporal retina). Measurements were taken at seven alignment positions across the pupil for each fixation angle. Refraction was recorded as the spherical and cylindrical power. RESULTS: The central objective refraction achieved under cycloplegia based on the autorefraction result for the whole sample, ranged between -5.62 D and +1.85 D for the value of sphere, with a maximum astigmatism of -1.00 D. Acceptable alignment position range varied with fixation angle but was -1.0 to +1.0 mm in width across the pupil. Peripheral refraction measurements centred on the entrance pupil were as reliable as those centred on the corneal reflex. CONCLUSIONS: Our data suggest that for peripheral refraction measurements, there is a range of acceptable positions and operators can be confident of the validity of results obtained if aligned half way between the pupil centre and corneal reflex. The alignment becomes more critical at greater eccentricities.

The Effect of Meibomian Gland Dysfunction Treatment on Sleep Quality.

PURPOSE: To assess the therapeutic efficacy of a combinational therapy, including conventional treatment and intense pulsed light (IPL) technique on sleep quality of patients with meibomian gland dysfunction (MGD). METHODS: Fifty participants with a clinical diagnosis of MGD were enrolled in this study. Participants underwent three sessions of IPL therapy. There was a 2-week interval between IPL sessions 1 and 2 and 1 month between sessions 2 and 3. Treatment was supplemented with conventional home-based therapy (including lid hygiene, warm compress, eyelid massage, and lid margin scrub) for MGD. Dry eye symptomatology, tear film, and ocular surface parameters were evaluated at baseline (day 0) and days 15, 45, and 75. Sleep quality was assessed before and after the study using Pittsburgh Sleep Quality Index (PSQI). RESULTS: PSQI components improved significantly at day 75 in comparison with the baseline (all P < 0.05). Ocular Surface Disease Index (OSDI) score, noninvasive Keratograph tear break-up time (NIKBUT), fluorescein tear break-up time (FTBUT), meibomian gland expressibility, meibum quality score, and tear osmolarity improved at follow-up visits (P < 0.05). Younger patients showed more improvement in NIKBUT, sleep quality, and duration (P = 0.024, P = 0.047, and P = 0.008). Sleep latency decreased with increased NIKBUT and FTBUT and decreased OSDI score (P = 0.001, P = 0.005, and P = 0.041). CONCLUSIONS: The treatment of MGD is effective for improving sleep quality. Younger patients may preferentially benefit from the treatment.

Effect of cyclopentolate versus tropicamide on anterior segment angle parameters in three refractive groups.

CLINICAL RELEVANCE: Frequent clinical application of cycloplegia in clinical practice makes it essential to assess how this condition influences anterior segment angle parameters. BACKGROUND: This study aims to compare the effects of cyclopentolate and tropicamide on anterior segment angle parameters in three adult refractive groups. METHODS: Sixty healthy individuals were recruited and assigned into three refractive groups according to inclusion criteria. At baseline visit, anterior segment angle parameters were measured using anterior segment optical coherence tomography in the right eye. All measurements were repeated at two separate visits, one week apart, after administration of tropicamide 1% and cyclopentolate 1% at similar conditions. Main outcome measures were angle-opening distance, trabecular iris angle, trabecular iris space area and anterior chamber depth. Anterior segment angle parameters were recorded at temporal areas (180 degrees). RESULTS: Sixty participants (29 men and 31 women, age: 27.82 ± 4.71-years) completed the experiment. Baseline mean spherical equivalents were +1.52 ± 1.20 D, -0.04 ± 0.33 D and -1.91 ± 0.91-D in hyperopic, emmetropic and myopic groups, respectively. No statistically significant differences were found between tropicamide and cyclopentolate for all angle parameters in three refractive groups. Both drops induced an increase in all parameters in three refractive groups. Analysis between refractive groups revealed that a more hyperopic refraction was associated with less trabecular iris angle, angle-opening distance and anterior chamber depth parameters in baseline, after tropicamide and cyclopentolate instillations. CONCLUSIONS: Topical application of cycloplegic eye drops in healthy individuals leads to small but significant changes in anterior chamber depth and anterior segment angle parameters, regardless of refractive status. Moreover, lower values of anterior chamber depth and anterior segment angle parameters in hyperopic individuals after administration of cycloplegic drops should be taken into account during biometric measurement and phakic intraocular lens implantation. Due to shorter effect and recovery time and less ocular/systemic reaction of tropicamide versus cyclopentolate, tropicamide could be a recommended cycloplegic agent for diagnostic and therapeutic procedures.

Under-correction or full correction of myopia? A meta-analysis.

PURPOSE: To compare the effect of full-correction versus under-correction on myopia progression. METHODS: A literature search was performed in PubMed, Scopus, Science Direct, Ovid, Web of Science and Cochrane library. Methodological quality assessment of the literature was evaluated according to the Critical Appraisal Skills Program. Statistical analysis was performed using Comprehensive Meta-Analysis (version 2, Biostat Inc., USA). RESULTS: The present meta-analysis included six studies (two randomized controlled trials [RCTs] and four non-RCTs) with 695 subjects (full-correction group, n=371; under-correction group, n=324) aged 6 to 33 years. Using cycloplegic refraction, the pooled difference in mean of myopia progression was - 0.179 D [lower and higher limits: -0.383, 0.025], which was higher but not in full correction group as compared to under correction group (p=0.085). Regarding studies using non-cycloplegic subjective refraction according to maximum plus for maximum visual acuity, the pooled difference in myopia progression was 0.128 D [lower and higher limits: -0.057, 0.312] higher in under-correction group compared with full-correction group (p=0.175). Although, difference in myopia progression did not reach significant level in either cycloplegic or non-cycloplegic refraction. CONCLUSIONS: Our findings suggest that, myopic eyes which are fully corrected with non-cycloplegic refraction with maximum plus sphere, are less prone to myopia progression, in comparison to those which were under corrected. However, regarding cycloplegic refraction, further studies are needed to better understand these trends.

The Effect of Contact Lens-spectacle Reversed Galilean Telescope on the Visual Field of Patients with Open-angle Glaucoma.

PURPOSE: Glaucoma causes irreversible visual field defects. This study aims to evaluate the effect of a reversed Galilean telescope on the visual field of patients with open-angle glaucoma. METHODS: Fifty-two glaucoma patients with a restricted visual field were recruited for this study. Central 30° visual field measurements were performed using a Humphrey visual field analyzer before and after applying the reversed Galilean telescope. To be more cosmetically acceptable, a combination of contact lens-spectacle was used as the reversed Galilean telescope. RESULTS: Our data analysis showed that the reversed Galilean telescope had a significant effect on all measured perimetric indices. Visual field index (VFI) improved from a basic value of 44.38 ± 26.96 to 49.30 ± 29.83 percent by using the reversed telescope (P < 0.001). Moreover, the mean deviation (MD) was significantly improved from the initial value of -19.91 ± 7.19 dB to a value of -18.69 ± 7.73 dB (P < 0.001). However, our results showed a significant reduction in the pattern standard deviation (PSD) comparing before (9.83 ± 2.82) and after (8.51 ± 3.30) values using the reversed Galilean telescope (P < 0.001). CONCLUSION: The contact lens-spectacle combination reversed Galilean telescope significantly improved the central 30° visual field of glaucoma patients with the restricted visual field.

Analysis of Age, Gender, and Refractive Error-Related Changes of the Anterior Corneal Surface Parameters Using Oculus Keratograph Topography.

PURPOSE: To assess refractive error, gender, and age-related differences in corneal topography of a normal population with Oculus Keratograph 4. METHODS: This cross-sectional study included a total of 500 normal eyes of 500 individuals with ages ranging from 10 to 70 years. All participants underwent detailed ocular examinations, including visual acuity measurement, slit-lamp examination, and refractive error evaluation. Slit-lamp examination was performed for all individuals to rule out apparent corneal diseases. Corneal topography parameters were assessed using Oculus Keratograph. The data were analyzed based on gender, refractive error, and age groups using independent sample t-test and one-way analysis of variance. RESULTS: Of a total of 500 participants (age: 29.51 ± 11.53 years) recruited for the present study, 66.4% were female, and 33.6% were male. The mean spherical equivalent of refraction was - 0.98 ± 1.65 diopters. Significant differences were noted in steep keratometry (P = 0.035) and corneal astigmatism (P = 0.014) between genders. Assessment of the data based on refractive error revealed significant differences in an index of vertical asymmetry (P < 0.001), index of height asymmetry (P = 0.003), and index of height decentration (P = 0.011). Considering age groups, significant differences were observed in flat keratometry readings (P < 0.001), mean corneal astigmatism (P = 0.02), minimum radius of curvature (P = 0.037), and apex power (P < 0.001). CONCLUSIONS: There was a prominent variation in some topographic parameters based on gender, age, and refractive error. The information on corneal parameters obtained with Oculus Keratograph from normal eyes provides a reference for comparison with diseased corneas.

Structure versus function in high myopia using optical coherence tomography and automated perimetry.

BACKGROUND: To examine the structure-function relationship between retinal thickness using spectral-domain optical coherence tomography and standard automated perimetry in high myopia. METHODS: The study population comprised 58 highly myopic individuals with no posterior abnormalities (mean spherical equivalent refraction ≤ -6.00 D and axial length ≥ 26.0 mm). All eyes underwent optical coherence tomography with the Spectralis spectral domain optical coherence tomograph and visual field evaluation with the Humphrey Field Analyzer II-i. Average macular layer thicknesses in each quadrant were calculated in a 6 × 6 mm area centred on the fovea. The visual field was assessed from 17 central locations (10°), approximately the equivalent of the area tested by optical coherence tomography in the macular scan. Linear correlations were made between different macular layer thicknesses and peripapillary retinal nerve layer thickness with their matched visual field sensitivities. RESULTS: Participant ages were 28.2 ± 6.4 years, mean spherical equivalent refractions were -8.20 ± 1.40 D and axial lengths were 26.7 ± 0.7 mm. There were significant positive correlations between layer thickness and corresponding visual field sensitivities as follows: ganglion cell layer in all quadrants, temporal quadrant of the nerve fibre layer with nasal quadrant of the visual field, inferior quadrant of the outer nuclear layer with superior visual field, and temporal-superior peripapillary nerve fibre layer with nasal-inferior visual field. CONCLUSION: The correlation between retinal layer thicknesses and visual field sensitivity could be explained by myopia-related losses due to lateral retinal stretching, with further research required to investigate this.

Normative values of visual evoked potentials in Northeastern of Iran.

PURPOSE: Visual evoked potentials (VEPs) provide important diagnostic information related to the functional integrity of the visual pathways. The aim of this study was to establish normative values of different components of pattern reversal VEPs on Iranian normal adult subjects. METHODS: Monocular and binocular pattern reversal VEPs were recorded on 59 healthy participants (22.55±3.79 years old) using the Roland RETI system for two check sizes of 15 and 60min of arc. The measured VEP components were the latencies of N75, P100, N135 and amplitude of N75-P100. RESULTS: Repeated measures ANOVA showed that viewing eye condition has a significant impact on the amplitude of N75-P100 (P<0.001, F=13.89). Also, the effect of check size on the latencies of N75, P100, N135, amplitude of N75-P100 (P≤0.010), as well as the intraocular difference of P100 latency and amplitude N75-P100 (P=0.007) was significant. More specifically, the amplitude of N75-P100 in both check sizes significantly differed between gender groups (P<0.023). CONCLUSION: According to the results of this study, VEPs components are affected by the stimulus size, monocular and binocular recording conditions and gender. Therefore, it is necessary to determine the normative values of VEPs in each population, so that the results could be used in clinical studies.