Consuelo Pérez-Rico

Pterygium is a benign fibrovascular lesion of the bulbar conjunctiva with frequent involvement of the corneal limbus. Its pathogenesis has been mainly attributed to sun exposure to ultraviolet-B radiation. Obtained evidence has shown that it is a complex and multifactorial process which involves multiple mechanisms such as oxidative stress, dysregulation of cell cycle checkpoints, induction of inflammatory mediators and growth factors, angiogenic stimulation, extracellular matrix (ECM) disorders, and, most likely, viruses and hereditary changes. In this review, we aim to collect all authors’ experiences and our own, with respect to the study of fibroelastic ECM of pterygium. Collagen and elastin are intrinsic indicators of physiological and pathological states. Here, we focus on an in-depth analysis of collagen (types I and III), as well as the main constituents of elastic fibers (tropoelastin (TE), fibrillins (FBNs), and fibulins (FBLNs)) and the enzymes (lysyl oxidases (LOXs)) that carry out their assembly or crosslinking. All the studies established that changes in the fibroelastic ECM occur in pterygium, based on the following facts: An increase in the synthesis and deposition of an immature form of collagen type III, which showed the process of tissue remodeling. An increase in protein levels in most of the constituents necessary for the development of elastic fibers, except FBLN4, whose biological roles are critical in the binding of the enzyme LOX, as well as FBN1 for the development of stable elastin. There was gene overexpression of TE, FBN1, FBLN5, and LOXL1, while the expression of LOX and FBLN2 and -4 remained stable. In conclusion, collagen and elastin, as well as several constituents involved in elastic fiber assembly are overexpressed in human pterygium, thus, supporting the hypothesis that there is dysregulation in the synthesis and crosslinking of the fibroelastic component, constituting an important pathogenetic mechanism for the development of the disease.

This study aimed to assess the role of multifocal visual-evoked potentials (mfVEPs) as a guiding factor for clinical conversion of radiologically isolated syndrome (RIS). We longitudinally followed a cohort of 15 patients diagnosed with RIS. All subjects underwent thorough ophthalmological, neurological and imaging examinations. The mfVEP signals were analysed to obtain features in the time domain (SNR_min: amplitude, Lat_max: monocular latency) and in the continuous wavelet transform (CWT) domain (b_max: instant in which the CWT function maximum appears, N_max: number of CWT function maximums). The best features were used as inputs to a RUSBoost boosting-based sampling algorithm to improve the mfVEP diagnostic performance. Five of the 15 patients developed an objective clinical symptom consistent with an inflammatory demyelinating central nervous system syndrome during follow-up (mean time: 13.40 months). The (SNR_min) variable decreased significantly in the group that converted (2.74 ± 0.92 vs. 4.07 ± 0.95, p = 0.01). Similarly, the (b_max) feature increased significantly in RIS patients who converted (169.44 ± 24.81 vs. 139.03 ± 11.95 (ms), p = 0.02). The area under the curve analysis produced SNR_min and b_max values of 0.92 and 0.88, respectively. These results provide a set of new mfVEP features that can be potentially useful for predicting prognosis in RIS patients.

Precis: At 6 months the procedure achieved a 33.89% drop in intraocular pressure (IOP), had an overall success rate of 57.15%, and did not change the best-corrected visual acuity. Achieving 20% from the preoperative value without antiglaucoma treatment and as qualified if that level was achieved with antiglaucoma medications. Preoperative and postoperative factors were evaluated for an association with postoperative success using Kaplan-Meier analysis. Results: A significant reduction in mean IOP from preoperative levels was evident at the end of the follow-up. The overall surgical success rate was 57.15%. On the basis of Kaplan-Meier survival analysis, we found that patients whose IOP on the following day of the procedure was <8 mm Hg had a higher success rate than those whose 1-day postoperative IOP was higher. These patients had a percentage of success of 100%, 84.6%, and 76.9% at 1-, 3-, and 6-month postoperative follow-up, respectively. Conclusion: The IOP level on the first postoperative day could be considered a prognostic indicator of success in needling revision performed in failed NPDS.

Background: To induce a moderate chronic ocular hypertension (OHT) by injecting polidocanol, a foamed sclerosant drug, in the aqueous humor outflow pathway. Methods: Intraocular pressure (IOP) was monitored for up to 6 months. Pattern and full-field electroretinogram (PERG and ERG) were recorded and retinal ganglion cells (RGC) and retinal nerve fiber layer (RNFL) thickness were assessed in vivo with optical coherence tomography (OCT) and ex vivo using Brn3a immunohistochemistry. Results: In the first 3 weeks post-injection, a significant IOP elevation was observed in the treated eyes (18.47 ± 3.36 mmHg) when compared with the control fellow eyes (12.52 ± 2.84 mmHg) (p < 0.05). At 8 weeks, 65% (11/17) of intervention eyes had developed an IOP increase >25% over the baseline. PERG responses were seen to be significantly reduced in the hypertensive eyes (2.25 ± 0.24 µV) compared to control eyes (1.44 ± 0.19 µV) (p < 0.01) at week 3, whereas the ERG components (photoreceptor a-wave and bipolar cell b-wave) remained unaltered. By week 24, RNFL thinning and cell loss in the ganglion cell layer was first detected (2/13, 15.3%) as assessed by OCT and light microscopy. Conclusions: This novel OHT rat model, with moderate levels of chronically elevated IOP, and abnormal PERG shows selective functional impairment of RGC.

Purpose: To investigate the feasibility, effectiveness and acceptability of using prosthetic occluding contact lenses (OCLs) to treat moderate amblyopia in adults and of the role of the multifocal visual evoked potential (mfVEP) as a predictor of postamblyopic therapy.Methods: A comparative, prospective, interventional, case series pilot study with amblyopic adults (mean age: 40 years, range 20–50 years) allocated into two intervention groups: eye patching and OCL. The primary outcome variable was logarithm of the minimum angle of resolution (logMAR) best‐corrected visual acuity (BCVA), and secondary outcomes were mfVEP amplitude and latency and patients’ health‐related quality of life National Eye Institute Visual Function Questionnaire (NEI VFQ‐25).Results: Significant improvements in pre‐ to postamblyopic therapy BCVA were seen at 1.5 months in the OCL group [0.29 logMAR, 95% confidence interval (CI): 0.10–0.47 versus 0.11 logMAR, 95% CI: 0.02–0.19; p < 0.001] and eye patching group (0.29 logMAR, 95% CI: 0.17–0.40 versus 0.18 logMAR, 95% CI: 0.12–0.23; p < 0.01). Post‐treatment BCVA was inversely related to age (R: 0.009, 95% CI: −0.02 to −0.001; p = 0.04) and the presence of strabismus (R: −0.3, 95% CI: −0.434 to −0.17; p = 0.001). No significant changes in the number and size of the abnormal mfVEP amplitude and latency defects were observed after occlusion. The NEI VFQ‐25 composite score showed significant improvement in the OCL users at 12 months compared to eye patching.Conclusion: Significant vision improvement can be achieved, making occlusion with OCLs an effective and more acceptable therapy for adults with amblyopia.

Obstructive sleep apnea–hypopnea syndrome (OSAHS) is becoming widely accepted as a risk factor for glaucoma. We discuss the proposed mechanism involved in the pathogenesis of glaucoma in OSAHS, and review the published data on the association between these two conditions, as well as papers regarding functional and structural tests related with glaucomatous damage. There is increasing evidence that the prevalence of glaucoma is higher in OSAHS patients, especially in those with severe disease with apnea-hypopnea index (AHI) >30, and also that sleep disorders may be more frequent in patients with glaucoma, especially in those with normal tension glaucoma (NTG). Several ophthalmic signs and symptoms have been associated with this condition. Raised intraocular pressure (IOP), possibly related to increased body mass index, thinning of retinal nerve fiber layer (RNFL), and alteration of visual field (VF) indices has been demonstrated in many studies, in patients with no history of glaucoma or evidence of glaucomatous changes in the ophthalmic examination. A correlation of AHI with RNFL and VF indices has been described in some studies. Finally, corneal thinning, suspicious glaucomatous disc changes and anomalies in electrophysiological tests such as multifocal visual evoked potential have been described in patients with OSAHS, even in patients with normal findings in the optic nerve and VF, suggesting subclinical optic nerve involvement not detectable in conventional ophthalmic examinations. The pathogenesis of optic nerve involvement has been related to vascular and mechanical factors. Vascular factors include recurrent hypoxia with increased vascular resistance, autonomic deregulation, oxidative stress and inflammation linked to hypoxia and subsequent reperfusion, decreased cerebral perfusion pressure and direct hypoxic damage to the optic nerve. Proposed mechanical factors include increased IOP at night related to supine position and obesity, raised intracranial pressure and elastic fiber depletion in the lamina cribosa and/or trabeculum. In conclusion, ophthalmic evaluation should be recommended in patients with severe OSAHS, and the presence of sleep disorders should be investigated in patients with glaucoma, especially in NTG patients and in those with progressive damage despite controlled IOP, as treatment with continuous positive airway pressure may contribute to stabilizing the progression of glaucomatous damage.

Dysthyroid optic neuropathy is the most serious, although infrequent (8–10 %) complication in Graves’ orbitopathy (GO). It is known that early stages of compressive optic neuropathy may produce reversible visual field defects, suggesting axoplasmic stasis rather than ganglion cell death. This observational, cross-sectional, case–control study assessed 34 consecutive patients (65 eyes) with Graves’ hyperthyroidism and longstanding GO and 31 age-matched control subjects. The patients’ multifocal visual evoked potentials (mfVEP) were compared to their clinical and psychophysical (standard automated perimetry [SAP]) and structural (optic coherence tomography [OCT]) diagnostic test data. Abnormal cluster defects were found in 12.3 % and 3.1 % of eyes on the interocular and monocular amplitude analysis mfVEP probability plots, respectively. As well, mfVEP latencies delays were found in 13.8 and 20 % of eyes on the interocular and monocular analysis probability plots, respectively. Interestingly, 19 % of patients with GO had ocular hypertension, and a strong correlation between intraocular pressure measured at upgaze and mfVEP latency was found. MfVEP amplitudes and visual acuity were significantly related to each other (P < 0.05), but not with the latencies delays. However, relationships between the interocular or monocular mfVEP amplitudes and latencies analysis and SAP indices or OCT data were not statistically significant. One-third of our patients with GO showed changes in the mfVEP, indicating significant subclinical optic nerve dysfunction. In this sense, the mfVEP may be a useful diagnostic tool in the clinic for early diagnosis and monitoring of optic nerve function abnormalities in patients with GO.

Background This study was designed to objectively evaluate visual function and the causal relationship between sleep apnea and optic nerve dysfunction in patients with obstructive sleep apnea syndrome (OSAS) with or without diagnosis of normal-tension glaucoma (NTG) using multifocal visual evoked potentials (mfVEP). Methods This observational, cross-sectional study assessed 20 patients with recently diagnosed OSAS with or without NTG. Diagnosis of sleep apnea was based on overnight polysomnography (ApnoeScreen). All participants underwent a complete physical and ophthalmologic examination. MfVEP recordings obtained using VERIS software (Electro-Diagnostic Imaging, San Mateo, USA), SITA-standard 30-2 automated perimetry (Humphrey Visual Field Analyzer II) and optic coherence tomography (Topcon 3D OCT-1000) exams were performed to evaluate the changes. Results Abnormal mfVEP amplitudes defects (interocular and monocular probability analysis) were found in 40% of the eyes in the non-glaucoma group and in 90% of eyes of the NTG patients. As well, delayed mfVEP latencies (interocular and monocular probability analysis) were seen in 30 and 60% of the eyes of the non-glaucoma and NTG groups, respectively. The average RNFL (retinal nerve fiber layer) thickness was significantly reduced in the NTG eyes compared to the control database and the non-glaucoma eyes. On the Humphrey Visual Field total deviation analysis, all the NTG eyes showed significant clusters of abnormal points but none was detected in the non-glaucoma group eyes. However, the mfVEP amplitude and latency did not show any significant correlation with the standard perimetry and OCT variables, because the mfVEP technique was able to detect far more early visual defects in these patients. Systolic blood pressure, sleep efficiency, arousal index, mean and minimum arterial oxygen saturation (SaO₂), time SaO₂ < 90%, oxyhemoglobin desaturation index, number of central and mixed apneas and apnea-hipopneas index were shown to be significantly correlated with mfVEP amplitude and latency. Conclusions A significant incidence of subclinical optic nerve involvement, not detected with other structural and psychophysics diagnostic techniques was seen by means of the mfVEP. In this sense, the mfVEP may be a useful diagnostic tool in the clinic for early diagnosis and monitoring of optic nerve function abnormalities in patients with OSAS.