Could Corneal Densitometry be a Progression Criterion for Subclinical Keratoconus?

Objectives: The objective of this study is to investigate the changes in topometry, tomography, and corneal densitometry in subclinical keratoconus (SK) at the 6-month interval. Methods: The clinical keratoconus and SK groups included 25 eyes; the control group included 22 eyes from 22 patients. Corneal topographic, tomographic, topometric, and densitometric values obtained using the Pentacam HR imaging system were analyzed. Results: Posterior elevation (PE), Keratoconus index (KI), index of height asymmetry (IHA), index of height decentration (IHD), Dp, Da, Final D, maximum pachymetric progression index (PPImax), and maximum Ambrósio relational thickness parameters showed significant changes between the baseline and the 6th-month follow-up in SK group (p<0.05 for all values). There were significant changes in all zones except a central layer of 6-10 zone, anterior, and central layer of 10-12 zone between the baseline and the 6th-month follow-up in the SK group (p<0.05, for all values). The changes in mean±standard deviation of KI, IHA, IHD, PPImax parameters, and corneal densitometry values of the posterior layer of 0-2 mm and 2-6 mm zones were significant in the SK group compared to the controls (p<0.05, for all values). Conclusion: PE, KI, IHA, IHD, and PPImax parameters as well as increasing corneal light backscatter of the posterior central layer might be useful for follow-up of progression of SK. New multimeric parameters created by combinations of topometric, tomographic, and corneal densitometry parameters could be the future of SK follow-up.

Evaluation of Choroidal Vascular Structure in Hyperopic Anisometropic Amblyopia.

Objectives: The aim of the study was to investigate the choroidal structure of patients with anisohypermetropic amblyopia compared to that of healthy eyes in controls of the same age. Methods: The study comprises three groups: One group was the amblyopic eyes of patients with anisometropic hypermetropia (AE group), another group was the fellow eyes of patients with anisometropic hypermetropia (FE group), and a final group of healthy controls. Both the choroidal thickness (CT) and choroidal vascularity index (CVI) values were obtained using the spectral-domain optical coherence tomography (OCT) method of improved depth imaging (EDI-OCT; Heidelberg Engineering GmbH, Spectralis, Germany, Heidelberg). Results: This study included 28 anisometropic amblyopic patients (AE and FE groups) and 35 healthy controls. Regarding the distribution of ages and sexes (p=0.813 and p=0.745), the groups were the same. The mean best-corrected visual acuity in AE, FE, and the control group was 0.58±0.76, 0.008±1.30, and 0.004±1.20 logMAR units, respectively. There was a significant difference in terms of CVI, luminal area (LA), and all the CT values between groups. Post hoc univariate analyses indicated that CVI and LA were significantly higher in AE compared to FE and the control group (p<0.05, for each). The temporal, nasal, and subfoveal CT values were considerably higher in AE compared to FE and the control groups (p<0.05, for each). However, there was no difference between FE and the control group (p>0.05, for each). Conclusion: The AE group had larger LA, CVI, and CT values compared to the FE and control groups. These results show that choroidal changes in amblyopic eyes in children are permanent in adulthood if untreated and are involved in the pathogenesis of amblyopia.

Choroidal Vascular Index in Patients With Attention-Deficit/Hyperactivity Disorder and Methylphenidate.

PURPOSE: To investigate choroidal vascularity in children with attention-deficit/hyperactivity disorder (ADHD) who were not receiving therapy, children with ADHD who were regularly taking methylphenidate (MPH), and healthy controls. METHODS: The study included three groups: patients with newly diagnosed ADHD without treatment, patients diagnosed as having ADHD who were already being treated with oral MPH, and controls. Both choroidal vascularity index (CVI) and choroidal thickness were measured using an enhanced-depth imaging mode of spectral-domain optical coherence tomography (EDIOCT) (Spectralis; Heidelberg Engineering GmbH). RESULTS: There was a significant difference in CVI and stromal area between groups. Post-hoc univariate analysis showed that CVI was significantly lower in patients with ADHD treated with MPH compared with the other groups (P < .001, for each); however, there was no difference between the treatment-free ADHD group and controls (P = .305). In contrast, stromal area was significantly higher in patients with ADHD treated with MPH than the other groups (P < .001, for each group). The correlation of CVI with MPH treatment duration in patients with ADHD treated with MPH showed a significant, moderate negative correlation (P = .01, r = - 0.66). CONCLUSIONS: CVI is reduced in patients with ADHD treated with MPH, and the decrease in CVI becomes significant with increasing duration of MPH treatment. This result reflects an indirect effect of MPH treatment on choroidal vascular structures. [J Pediatr Ophthalmol Strabismus. 2023;60(6):411-416.].

Assessment of Tear Meniscus Dimensions Using Anterior Segment Optical Coherence Tomography in Vitamin D Deficiency in a Pediatric Population.

BACKGROUND: To investigate of the effect of vitamin D (Vit-D) deficiency on the tear film in children and compare it with that of healthy subjects. METHODS: This prospective and cross-sectional study comprised 75 eyes of children who had Vit-D deficiency (Group 1) and 85 eyes of age- and gender-matched healthy children (Group 2). The tear-film break-up time (TF-BUT) and Schirmer test values, as well as the Ocular Surface Disease Index (OSDI) scores, were recorded for the participants in all groups. Measurement of the tear meniscus area (TMA) and tear meniscus height (TMH) was performed 2 times in the same day via the use of anterior segment-optical coherence tomography (AS-OCT). RESULTS: The mean age of the participants in Group 1 was 12.42 ± 3.40 years, while in Group 2, it was 12.59 ± 2.32 years (p = 0.758). Group 1 comprised 43 females and 32 males, while Group 2 comprised 44 females and 41 males (p = 0.250). The mean TMH, TMA, and Schirmer test values were found to be significantly lower in children with Vit-D deficiency (Group 1) than in healthy children (Group 2), with p < 0.05 for all the values. It was concluded that there was no significant difference in the values for the mean TF-BUT and OSDI scores (p = 0.029 and p = 0.596, respectively). CONCLUSION: The children with Vit-D deficiency exhibited lower TMH, TMA, and Schirmer test values. The alterations that were observed in these parameters were more prominent in the participants who had lower Vit-D levels.

Evaluation of Retinal Layer Thicknesses in Patients with Keratoconus Using Retinal Layer Segmentation Analysis.

OBJECTIVE: To conduct an evaluation of the effects of irregular astigmatism on the retinal nerve fiber layer (RNFL) and the retinal layers observed using spectral-domain optical coherence tomography (SD-OCT) in patients who had keratoconus (KC). MATERIALS AND METHODS: A total of 255 eyes from 255 individuals, comprising 72 eyes of KC patients, 70 eyes of patients with astigmia, and 113 eyes of healthy controls were included in the analysis. RNFL scan maps (comprising global, temporal, superotemporal, inferotemporal, nasal, inferonasal, and superonasal maps) and macular thickness (MT) maps of a standard from the Early Treatment Diabetic Retinopathy Study (ETDRS) grid were assessed. The measurements were segmented automatically using Spectralis software, and included the RNFL, inner and outer plexiform layers (IPL, OPL), inner and outer nuclear layers (INL, ONL), ganglion cell layer, retinal pigment epithelium (RPE) in the central 6-mm ETDRS subfield. RESULTS: The RNFL thickness in the KC group was lower when compared with the other two groups; however, statistically significant differences were noted in the global, temporal, superotemporal, and inferotemporal sectors (p < 0.05 for all). All of the central MT parameters showed significant variation among the groups, while a statistically significant decrease was noted in the KC group, except in the inferior outer sector (p = 0.741). In the segmentation analysis, the KC group had the significantly lowest IPL, ONL, RPE, and outer retinal layer (ORL) thickness among the groups (p < 0.05 for each). The astigmatic group was similar to the control group with regard to these parameters (p > 0.05 for each). CONCLUSION: The eyes in the KC group appeared to have a thinner RNFL and MT when compared to those in the astigmatic and control groups. The ORLs, especially the ONL and RPE, were the most affected component of the macula in the KC group.

Effects on Wavefront Aberration after Short-term Wear of Senofilcon A Photochromic Contact Lens.

BACKGROUND: To assess the variability in wavefront aberrations with short-term wear of photochromic senofilcon A contact lenses in both its activated and inactive states. METHODS AND MATERIAL: In this cross-sectional study, 20 participants who had previously used soft contact lenses were enrolled. Corneal aberrometry measurements were performed on each subject, without contact lenses, using Sirius Scheimpflug-Placido topography. The photochromic lenses were illuminated using a blue-violet light (λ max = 420 nm) so as to provoke an activated state, and measurements were taken with the lenses inserted, in both states. The root mean square (RMS) of the aberrations was calculated, and the higher- and lower-order aberrations, astigmatism, coma, spherical aberration, and trefoil measurements were evaluated using a 5.0-mm pupil diameter. RESULTS: The average contact lens sphere power was - 2.33 ± 1.07 D. The mean refractive errors with contact lens wear were 0.07 ± 0.18 D for the sphere and - 0.26 ± 0.15 D for the cylinder. The mean RMS values for all the corneal aberrations showed no statistically significant differences with and without contact lenses (p > 0.05). In a bivariate correlation analysis, there was a positive correlation between contact lens sphere power and coma (vertical and horizontal) in the activated state (r = 0.455, p = 0.44 and r = 0.495, p = 0.27, respectively). CONCLUSION: The photochromic contact lenses did not influence ocular aberration during short-term wear, even when the photochromatic additive was activated. This property may help to provide more comfortable vision with lens wear. This finding needs to be verified by further studies.

Assessment of corneal endothelial cell morphology and anterior segment parameters in COVID-19.

Background: The ocular manifestations of the 2019 novel coronavirus disease (COVID-19) vary from acute follicular, pseudomembranous, and hemorrhagic conjunctivitis to keratoconjunctivitis with subepithelial infiltrates and dendritic lesions. Similar to other respiratory viruses, such as adenoviruses, it is thought that COVID-19 may impact the cornea. However, its impact on the cornea and anterior segment parameters are currently poorly understood. Objective: This study aims to assess the corneal endothelial cell morphology and anterior segment parameters in patients who have recovered from COVID-19. Methods: In this cross-sectional study, the COVID-19 group comprised 34 patients who had been diagnosed with and recovered from COVID-19, while the control group comprised age- and sex-matched individuals without any systemic or ocular diseases. The endothelial cell density (ECD), coefficient of variation (CV) of cell area, hexagonal cell percentage (HEX), anterior chamber depth (ACD), central corneal thickness (CCT), horizontal anterior chamber diameter (HACD), iridocorneal angle (ICA), horizontal visible iris diameter (HVID), pupillary diameter (PD), and keratometry values (K1 and K2) were analyzed for each participant. The differences in each of these between the groups were analyzed using either an independent samples t test or a Mann-Whitney U test based on the normality of the data. Results: Regarding corneal endothelial cell morphology, the ECDs for the COVID-19 and control groups were 2278.50 ± 186.78 cells/mm2 and 2420.15 ± 222.25 cells/mm2, respectively (p = 0.002). A significant increase was noted in CV values in the COVID-19 group compared with the control group (p < 0.001). The HEX values for the COVID-19 and control groups were 56.26 ± 5.75 and 61.50 ± 3.63, respectively (p < 0.001). Regarding the anterior segment parameters, no significant differences were observed between the groups (p > 0.05). Conclusions: It was hypothesized that individuals who had recovered from COVID-19 would demonstrate a reduction in their endothelial functional preserves. A decrease in ECD and HEX and an increase in CV were observed in the individuals during their early post-recovery period from COVID-19.

Comparative Evaluation of Central Corneal Thickness in Cross-Linked Keratoconic Eyes.

PURPOSE: To compare the central corneal thickness (CCT) measurements measured by using the Pentacam Scheimpflug system with the CCT measured using ultrasound pachymetry (UP) and to compare the compatibility between the methods in normal, keratoconic, and cross-linked keratoconic corneas. METHODS: The study included 50 eyes of 50 patients with keratoconus (keratoconus group), 50 eyes of 50 patients with progressive keratoconus who underwent corneal cross-linking treatment (CCL group), and 50 eyes of 50 healthy subjects (control group). Patients in the keratoconus and CCL groups were further classified into mild (mean keratometry [Km] ≤ 47 D) and moderate keratoconus subgroups (47.0 < Km < 52.0 D). CCT values were noted from the Pentacam Scheimpflug and UP. RESULTS: The difference between the Pentacam and UP values was largest in the CCL group (-20.9 0.21.5 µm), followed by the keratoconus and control groups (-10.6 0.20.3 and 0.4 0.6.8 µm). The Pentacam and UP measurements were not comparable in the keratoconus and CCL groups (P = 0.001 and P < 0.001), whereas they were comparable in the control group (P = 0.62). In subgroup analysis, the 2 methods were comparable in the mild keratoconus subgroup (P = 0.12) and not comparable in the moderate keratoconus subgroup and in both mild and moderate subgroups of the CCL group (P = 0.001, P < 0.001 and P < 0.001). CONCLUSIONS: Pentacam Scheimpflug tomography and UP can be used interchangeably in normal and mild keratoconic eyes, but not in moderate keratoconic and cross-linked keratoconic eyes. Pachymetry measurements from Scheimpflug must be interpreted with extreme caution with different methods before planning an invasive procedure in these eyes.