Carracedo Rodríguez, Juan Gonzalo

Profile Picture
First Name
Juan Gonzalo
Last Name
Carracedo Rodríguez
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Optometría y Visión
UCM identifierORCIDScopus Author IDDialnet IDGoogle Scholar ID

Search Results

Now showing 1 - 7 of 7
  • Publication
    A review of international medical device regulations: Contact lenses and lens care solutions
    (Elsevier, 2018-11-14) Zaki, Marina; Pardo, Jesús; Carracedo Rodríguez, Juan Gonzalo
    Medical devices are under strict regulatory oversight worldwide and such regulations prioritise patient safety and efficacy over anything else. Contact lenses fall under the medical device category - a result of direct contact with the eye. Equally regulated are the contact lens care product solutions, which include cleaning and maintenance solutions and lubricating and rewetting drops. In the USA, it is the FDA Centre for Devices and Radiological Health (CDRH) overseeing the regulations of medical devices, since 1976. In the European Union, it is the EU Commission responsible for regulating devices in Member States. The categorisation of contact lenses into medical devices is based on their inherent risk to the wearer. Contact lenses are subject to crucial regulatory oversight from concept to clinical evaluation, clinical investigations through to the finished lens product, and finally, strict conditions associated with their marketing approval including post-marketing surveillance. The physiochemical and manufacturing testing, such as biocompatibility testing alongside pre-clinical stability, sterility and microbiological testing are just some of the essential testing lenses must endure. Only through understanding the inherent risks and potential complications that can arise from contact lens wear, can one truly appreciate the need to adhere to strict regulations. The challenge however, lies in the need for more standardised regulations and flexible approaches, ensuring innovative device technologies reach patients in a timely manner without compromising public health and safety. This review highlights some key requirement, differences and similarities between the FDA and EU administrations in the approval of contact lenses.
  • Publication
    Corneal surface wettability and tear film stability before and after scleral lens wear
    (Elsevier, 2019-04-06) Serramito Blanco, María; Privado Aroco, Ana; Batres Valderas, Laura; Carracedo Rodríguez, Juan Gonzalo
    Purpose: The aim of this study was to evaluate the anterior surface of scleral contact lens and ocular surface wettability before and after one-month of scleral lens wear in patients with keratoconus. Methods: Forty-nine patients with keratoconus (36.26 ± 9.03 years) were recruited. The sample was divided into two groups: patients with intrastromal corneal ring (KCICRS group) and patients without ICRS (KC group). TFSQ, Schirmer I test, Ocular Surface Disease Index (OSDI questionnaire), tear break-up time (TBUT) and corneal staining were evaluated in two different visits: Baseline (before lens wear) and one-month visit (10 min after lens removal). Visual Analog Scale (VAS questionnaire) was filled in just after inserting the lenses and just before removing them. TFSQ mean and inferior were evaluated over the contact lens surface at the moment of inserting the lens (baseline visit) and after 8 h of lens wear (one-month visit). Results: Anterior corneal surface TFSQ values increased in all groups after scleral lens wear (p < 0.05). However, there were no statistical differences found at the moment of inserting or after 8 h of lens wear on previous contact lens surface TFSQ (p > 0.05). No changes were found in tear volume for total and in KC and KCICRS groups (p > 0.05). For all groups, there was a statistical decrease of TBUT (p < 0.05). In addition, OSDI score, corneal staining and VAS score improved after scleral lens wear from baseline in total and in both KC and KCICRS groups (p < 0.05). Conclusion: The scleral contact lens surface keeps its wettability after one-month of wear. However, the wettability of the ocular surface is worse after contact lens wearing.
  • Publication
    Short-term Effect of Scleral Lens on the Dry Eye Biomarkers in Keratoconus
    (Lippincott Williams & Wilkins, 2016-02) Carracedo Rodríguez, Juan Gonzalo; Serramito Blanco, María; Martín Gil, Alba; Wang, Zicheng; Carballo Álvarez, Jesús; Pintor, Jesús
    Purpose: To evaluate the most important signs of dry eye, such as osmolarity, inflammation, and diadenosine tetraphosphate (Ap4A) concentration before and after wearing scleral lenses for 8 h in keratoconus patients. Methods: A pilot, experimental, short-term study involved 26 keratoconus patients (average age, 36.95 ± 8.95 years). They voluntarily enrolled in the study at the Optometry Clinic of the Faculty of Optics and Optometry in the University Complutense of Madrid. They were divided into two groups: patients with intrastromal corneal ring, the ICRS group, and patients without ICRS, the keratoconus (KC) group. Ocular Surface Disease Index questionnaire, the Schirmer test without anesthesia, tear break-up time, matrix metalloproteinase 9 (MMP-9) concentration, osmolarity, and Ap4A concentration were evaluated before and after wearing a scleral lens for 8 h. Results: The patients wore the scleral lenses from 6 to 9 h, with a mean of 7.59 ± 0.73 h. The mean scleral lens sag for all patients was 4310 ± 166.31 μm, ranging from 4200 μm to 4800 μm. No significant changes in the Schirmer test and tear break-up time were found for either group. Ocular Surface Disease Index scores were statistically lower after wearing scleral lenses for both groups (p < 0.05). A significantly lower osmolarity and a significant rise of MMP-9 concentration after wearing scleral lenses were found in both groups (p < 0.05). Diadenosine tetraphosphate concentration was lower after wearing the scleral lens in the KC group (p < 0.05) but no significant difference was found for the ICRS group (p > 0.05). Conclusions: Short-term scleral lens wearing improves the symptomatology and some signs of dry eye, such as osmolarity and Ap4A concentration. The increase of MMP-9 concentration could be caused by tear film stagnation and use of preserved saline.
  • Publication
    Posterior cornea and thickness changes after scleral lens wear in keratoconus patients
    (Elsevier, 2018-05) Serramito Blanco, María; Carpena Torres, Carlos; Carballo Álvarez, Jesús; Piñero, David Pablo; Lipson, Michael; Carracedo Rodríguez, Juan Gonzalo
    Purpose: To evaluate the changes in the corneal thickness, anterior chamber depth and posterior corneal curvature and aberrations after scleral lens wear in keratoconus patients with and without intrastromal corneal ring segments (ICRS). Methods:Twenty-six keratoconus subjects (36.95 ± 8.95 years) were evaluated after 8 h of scleral lens wear. The subjects were divided into two groups: those with ICRS (ICRS group) and without ICRS (KC group). The study variables evaluated before and immediately after scleral lens wear included corneal thickness evaluated in different quadrants, posterior corneal curvature at 2, 4, 6 and 8 mm of corneal diameter, posterior corneal aberrations for 4, 6 and 8 mm of pupil size and anterior chamber depth. Results: There was a statistically significant corneal thinning (p < 0.05) in the inferior region of the KC group and in the superior region of the ICRS group. No change (p > 0.05) in the anterior chamber depth was found. The KC group showed a steepening (p < 0.05) in the temporal quadrant and a flattening that mainly affected to the superior-nasal quadrant. The ICRS group showed a steepening (p < 0.05) that mainly affected to the superior-nasal quadrant. Regarding posterior corneal aberrations, only changes (p < 0.05) in Z4 for 8 mm and Z8 for 4 mm were found in the KC group. Conclusions: Short-term scleral lens wear showed a thinning of the cornea and changes in the posterior corneal curvature affects different regions in keratoconus patients with and without ICRS.
  • Publication
    Variation of Coma Aberration With Prismatic Soft Contact Lenses
    (Wolters Kluwer, 2018-11) Carpena Torres, Carlos; López Alonso, José Manuel; Burgos Martínez, Mercedes; Carracedo Rodríguez, Juan Gonzalo; Carballo Álvarez, Jesús
    PURPOSE: To analyze the variation in vertical coma and the rest of ocular aberrations before and after fitting prismatic soft contact lenses (PSCL). METHODS: Thirty-seven eyes of 20 healthy subjects (24.30±2.03 years) were evaluated to analyze the variation in ocular wavefront aberrations before and after fitting PSCL of different base-down prism values (1.0, 1.5, and 2.0 prism diopters [PD]), designed to study its influence in the compensation of vertical coma aberration. A Hartmann-Shack sensor with a wavelength of 780 nm was used, considering a pupil size of 3 mm. In addition, the influence of PSCL in visual function under photopic conditions in terms of high-contrast visual acuity and contrast sensitivity was evaluated. RESULTS: There was statistically significant differences (P<0.05) in ocular aberrations from first to seventh order after fitting PSCL, but only the differences in vertical tilt, horizontal tilt, defocus, vertical astigmatism, and vertical coma were clinically relevant (Strehl ratio <0.8). The mean of vertical coma (μm) was 0.022±0.030 for control, 0.045±0.064 for 1.0 PD (P=0.645), 0.048±0.053 for 1.5 PD (P=0.037), and 0.074±0.047 for 2.0 PD (P<0.001). The changes in visual function under photopic conditions were not clinically relevant. CONCLUSIONS: PSCL induce a magnitude of vertical coma aberration directly proportional to prism value without affecting the rest of ocular high-order aberrations.
  • Publication
    Diquafosol Delivery from Silicone Hydrogel Contact Lenses: Improved Effect on Tear Secretion
    (Mary Ann Liebert, 2018-03-01) Dominguez Godínez, Carmen Olalla; Carracedo Rodríguez, Juan Gonzalo; Pintor, Jesús
    Purpose: The aim of this study was to evaluate the ability to uptake and to deliver diquafosol from commercial contact lenses (CLs) and its effect on tear secretion. Methods: For both in vitro and in vivo experiments, two commercial silicone hydrogel (Si-Hy) CLs (comfilcon A and balafilcon A) were used. The CLs were soaked overnight for 12 h in diquafosol solution and control CLs were soaked in saline solution (NaCl 0.9%). The CLs were introduced into a new well container with 1 mL of saline solution, and aliquots of 100 μL were extracted at different times during a period of 6 h to measure the diquafosol release. For in vivo experiments, nine male New Zealand white rabbits were used. CLs soaked in diquafosol were inserted in the eye and compared with control CLs and diquafosol topical instillation. Schirmer's tests were performed to evaluate tear secretion and diquafosol release at different times during the 6-h period. Results: For in vitro experiments, the largest amount of diquafosol was released during the first 24 h for both CL materials under study, without statistical differences between them (P < 0.05). The topical application showed the maximum release at 1 min after instillation, meanwhile the release from both CL materials was at 30 min of insertion. The effect on tear secretion was higher with CL delivery compared with topical instillation (P < 0.05), being 300 min for both CLs and 90 min for topical application. Conclusion: The use of CLs increases the residence time of diquafosol on the ocular surface with a concomitant enhancement in tear secretion during longer periods.
  • Publication
    Anterior Corneal Curvature and Aberration Changes After Scleral Lens Wear in Keratoconus Patients With and Without Ring Segments
    (Wolters Kluwer, 2019-03) Serramito Blanco, Maria; Carpena Torres, Carlos; Carballo, Jesús; Piñero, David; Lipson, Michael; Carracedo, Gonzalo; Serramito Blanco, María; Carpena Torres, Carlos; Carballo Álvarez, Jesús; Carracedo Rodríguez, Juan Gonzalo
    Objective: To evaluate changes in the anterior corneal curvature and aberrometry after scleral contact lens wear in keratoconus (KC) subjects with and without intracorneal ring segments (ICRS). Methods: Twenty-six subjects diagnosed with keratoconus were selected to participate in the study. Subjects were divided into 2 groups, those with ICRS (KC-ICRS group) and those without ICRS (KC group). Subjects were instructed to wear 16.5-mm scleral lenses for 8 hours. Topographic and aberrometric parameters were evaluated before lens wear and immediately after lens removal. Anterior corneal curvature was evaluated at corneal diameters of 2, 4, 6, and 8 mm, and corneal aberrations were measured at 4-, 6-, and 8-mm pupil diameters. Results: The mean age of subjects was 36.95±8.95 years. In KC group, there was a statistically significant flattening of the central corneal curvature, from 6.98 to 7.09 mm (P<0.05). No changes were found in the central corneal curvature in the KC-ICRS group. The KC group showed anterior corneal curvature flattening, mainly in the nasal quadrant. The KC-ICRS group showed flattening primarily in the inferior hemisphere. In the KC group, spherical aberration for 6-mm pupil increased significantly. In the KC-ICRS group, changes in aberrations were significant for high-order root mean square at 4- and 6-mm pupil diameters (P<0.05), for oblique astigmatism for 4 mm and 6 mm, and for vertical coma for 4-mm pupil (P<0.05). Conclusion: Short-term scleral lens wear showed flattening of the anterior corneal surface in all subjects. In the KC group, the flattening was more pronounced in the nasal quadrant while changes were more pronounced inferiorly in KC-ICRS group.