Topically instilled caffeine selectively alters emmetropizing responses in infant rhesus monkeys.

Oral administration of the adenosine receptor (ADOR) antagonist, 7-methylxanthine (7-MX), reduces both form-deprivation and lens-induced myopia in mammalian animal models. We investigated whether topically instilled caffeine, another non-selective ADOR antagonist, retards vision-induced axial elongation in monkeys. Beginning at 24 days of age, a 1.4% caffeine solution was instilled in both eyes of 14 rhesus monkeys twice each day until the age of 135 days. Concurrent with the caffeine regimen, the monkeys were fitted with helmets that held either -3 D (-3D/pl caffeine, n = 8) or +3 D spectacle lenses (+3D/pl caffeine, n = 6) in front of their lens-treated eyes and zero-powered lenses in front of their fellow-control eyes. Refractive errors and ocular dimensions were measured at baseline and periodically throughout the lens-rearing period. Control data were obtained from 8 vehicle-treated animals also reared with monocular -3 D spectacles (-3D/pl vehicle). In addition, historical comparison data were available for otherwise untreated lens-reared controls (-3D/pl controls, n = 20; +3D/pl controls, n = 9) and 41 normal monkeys. The vehicle controls and the untreated lens-reared controls consistently developed compensating axial anisometropias (-3D/pl vehicle = -1.44 ± 1.04 D; -3D/pl controls = -1.85 ± 1.20 D; +3D/pl controls = +1.92 ± 0.56 D). The caffeine regime did not interfere with hyperopic compensation in response to +3 D of anisometropia (+1.93 ± 0.82 D), however, it reduced the likelihood that animals would compensate for -3 D of anisometropia (+0.58 ± 1.82 D). The caffeine regimen also promoted hyperopic shifts in both the lens-treated and fellow-control eyes; 26 of the 28 caffeine-treated eyes became more hyperopic than the median normal monkey (mean (±SD) relative hyperopia = +2.27 ± 1.65 D; range = +0.31 to +6.37 D). The effects of topical caffeine on refractive development, which were qualitatively similar to those produced by oral administration of 7-MX, indicate that ADOR antagonists have potential in treatment strategies for preventing and/or reducing myopia progression.

Blockade of epidermal growth factor and its receptor and axial elongation in experimental myopia.

To examine the influence of epidermal growth factor (EGF) and its receptor (EGFR) on axial ocular elongation, we intraocularly injected an EGF antibody and an EGFR antibody into young guinea pigs with lens-induced axial elongation (myopization). Mean axial elongation was reduced in the eyes injected with the EGF/EGFR-antibody compared with the contralateral control eyes injected with PBS (phosphate-buffered solution) (0.43 ± 0.13 mm vs 0.53 ± 0.13 mm; P < .001). The intereye difference in axial length increased (P = .005) as the doses of the EGF antibody and EGFR antibody increased. As a corollary, the thickness of the retina at the posterior pole was dose-dependently increased in the injected eyes compared to the contralateral control eyes. Immunohistochemical staining for EGF and the relative mRNA expression of EGF and EGFR were the highest in eyes not injected with the EGF antibody or EGFR antibody and decreased (P < .05) as the dose of EGF antibody or EGFR antibody increased. In an in vitro study, EGF had a stimulating effect and the EGF antibody had an inhibitory effect on the proliferation and migration of RPE cells. The findings showed that the intravitreal application of an EGF antibody and EGFR antibody is associated with a dose-dependent reduction in lens-induced axial elongation in young guinea pigs. The EGFR family may play a role in axial elongation of the eye and in the development of myopia.

Optical biometry-based axial length alterations after intravitreal dexamethasone implant / Alterações do comprimento axial com base na biometria óptica após o implante de dexametasona intravítrea

ABSTRACT Purpose: To investigate changes in axial length after intravitreal dexamethasone implantation in patients with macular edema. Methods: We performed a prospective comparative study of 46 patients with unilateral macular edema, due to diabetic retinopathy, retinal vein occlusion, and non-infectious uveitis, who underwent dexamethasone implantation. The fellow eyes of the patients were considered the control group. The central macular thickness was measured by spectral-domain optical coherence tomography, and axial length was measured by IOLMaster 700 optical coherence biometry. We compared axial length and central macular thickness values within the groups. Results: In the study group, the baseline central macular thickness was 460.19 ± 128.64 mm, significantly decreasing to 324.00 ± 79.84 mm after dexamethasone implantation (p=0.000). No significant change in central macular thickness measurements was seen in the control group (p=0.244). In the study group, the baseline axial length was 23.16 ± 0.68 mm, significantly increasing to 23.22 ± 0.65 mm after dexamethasone implantation (p=0.039). However, the control group exhibited no significant change in axial length (p=0.123). Conclusions: In addition to significantly reducing central macular thickness measurements, intravitreal dexamethasone implantation also significantly changes optical biometry-based axial length measurements.

RESUMO Objetivo: Investigar alterações no comprimento axial após implante de dexametasona intravítrea em pacientes com edema macular. Métodos: Foi realizado um estudo prospectivo e comparativo de 46 pacientes com edema macular unilateral, devido à retinopatia diabética, oclusão da veia retiniana e uveíte não infecciosa, que foram submetidos ao implante de dexametasona. Os olhos contralateral de cada paciente foram considerados o grupo controle. A espessura macular central foi medida por tomografia de coerência óptica de domínio espectral, e o comprimento axial foi medido por meio de biometria de coerência óptica de domínio espectral e o comprimento axial foi medido pela biometria de coerência óptica com IOLMaster 700. Comparamos o comprimento axial e os valores da espessura macular central dentro dos grupos. Resultados: No grupo de estudo, a espessura macular basal foi de 460,19 ± 128,64 mm, diminuindo significativamente para 324,00 ± 79,84 mm após o implante de dexametasona (p=0,000). Nenhuma mudança significativa nas medidas da espessura macular central foi observada no grupo controle (p=0,244). No grupo de estudo, o comprimento axial basal foi de 23,16 ± 0,68 mm, aumentando significativamente para 23,22 ± 0,65 mm após o implante de dexametasona (p=0,039). No entanto, o grupo controle não apresentou alteração significativa no comprimento axial (p=0,123). Conclusões: Além de reduzir significativamente as medidas da espessura macular central, o implante de dexametasona intravítrea também altera significativamente as medidas de comprimento axial baseadas na biometria óptica.

Amphiregulin and ocular axial length.

PURPOSE: To assess the potential role of amphiregulin as messenger molecule in ocular axial elongation. METHODS: The experimental study included guinea pigs (total n = 78) (age: 3-4 weeks) which underwent bilateral lens-induced myopization and received 15 days later three intraocular injections in weekly intervals of amphiregulin antibody (doses:5 µg, 10 µg, 20 µg) into their right eyes, and three phosphate-buffered saline injections into their left eyes; and guinea pigs without lens-induced myopization and which received three unilateral intraocular injections of amphiregulin antibody (dose: 20 µg) or amphiregulin (doses: 1 ng; 10 ng; 20 ng) into their right eyes, and three phosphate-buffered saline injections into their left eyes. Seven days later, the animals were sacrificed. Intravitally, we performed biometry, and histology and immunohistochemistry post-mortem. RESULTS: In animals with bilateral lens-induced myopization, the right eyes receiving amphiregulin antibody showed reduced axial elongation in a dose-dependent manner (dose: 5 µg: side difference: 0.14 ± 0.05 mm;10 µg: 0.22 ± 0.06 mm; 20 µg: 0.32 ± 0.06 mm; p < 0.001), thicker sclera (all p < 0.05) and higher cell density in the retinal nuclear layers and retinal pigment epithelium (RPE) (all p < 0.05). In animals without lens-induced myopia, the right eyes with amphiregulin antibody application (20 µg) showed reduced axial elongation (p = 0.04), and the right eyes with amphiregulin injections experienced increased (p = 0.02) axial elongation in a dose-dependent manner (1 ng: 0.04 ± 0.06 mm; 10 ng: 0.10 ± 0.05 mm; 20 ng: 0.11 ± 0.06 mm). Eyes with lens-induced axial elongation as compared to eyes without lens-induced axial elongation revealed an increased visualization of amphiregulin upon immunohistochemistry and higher expression of mRNA of endogenous amphiregulin and epidermal growth factor receptor, in particular in the outer part of the retinal inner nuclear layer and in the RPE. CONCLUSION: Amphiregulin may be associated with axial elongation in young guinea pigs.

Optical biometry-based axial length alterations after intravitreal dexamethasone implant.

PURPOSE: To investigate changes in axial length after intravitreal dexamethasone implantation in patients with macular edema. METHODS: We performed a prospective comparative study of 46 patients with unilateral macular edema, due to diabetic retinopathy, retinal vein occlusion, and non-infectious uveitis, who underwent dexamethasone implantation. The fellow eyes of the patients were considered the control group. The central macular thickness was measured by spectral-domain optical coherence tomography, and axial length was measured by IOLMaster 700 optical coherence biometry. We compared axial length and central macular thickness values within the groups. RESULTS: In the study group, the baseline central macular thickness was 460.19 ± 128.64 mm, significantly decreasing to 324.00 ± 79.84 mm after dexamethasone implantation (p=0.000). No significant change in central macular thickness measurements was seen in the control group (p=0.244). In the study group, the baseline axial length was 23.16 ± 0.68 mm, significantly increasing to 23.22 ± 0.65 mm after dexamethasone implantation (p=0.039). However, the control group exhibited no significant change in axial length (p=0.123). CONCLUSIONS: In addition to significantly reducing central macular thickness measurements, intravitreal dexamethasone implantation also significantly changes optical biometry-based axial length measurements.

Scleral Cross-Linking Using Glyceraldehyde for the Prevention of Axial Elongation in the Rabbit: Blocked Axial Elongation and Altered Scleral Microstructure.

BACKGROUND: This study aims to assess the efficacy of the scleral collagen cross-linking method using glyceraldehyde solution for prevention of lens-induced axial elongation in New Zealand rabbits and investigate the biochemical and microstructural changes that occur. METHODS: The right eyes of New Zealand rabbits aged seven weeks were randomly divided into three groups: the cross-linking group (n = 6), non-crosslinking group (n = 5), and untreated control group (n = 5). Eyes in cross-linking and non-crosslinking groups were treated with a -8.00 Diopter spherical lens over the course of two weeks. The cross-linking effects were achieved by a sub-Tenon's injection of 0.15 ml 0.5 M glyceraldehyde to eyes in the CL group. Ocular parameters were measured on the 1st, 7th, and 14th days. Biomechanical testing, light and electronic microscopy were used. RESULTS: Following the cross-linking treatment, eyes in the cross-linking group had a shorter axial length compared to those in the non-crosslinking group (p = 0.006). Collagen fibrils larger than 240 nm were observed in the scleral stroma of cross-linking group, which were absent in the scleral stroma of the non-crosslinking and untreated control group. The mean ultimate stress and Young's modulus was significantly greater in the cross-linking group compared to those in the non-crosslinking and untreated control group (p < 0.05). No histological damage observed in the retina or choroid. CONCLUSIONS: This study demonstrates that lens-induced axial elongation in rabbits can be effectively blocked by cross-linking using glyceraldehyde, with anatomical and mechanical modification and no deleterious effects.

Riboflavin and ultraviolet A irradiation for the prevention of progressive myopia in a guinea pig model.

In this study, we evaluated the effect of oral administration of riboflavin combined with whole-body ultraviolet A (UVA) irradiation on the biochemical and biomechanical properties of sclera in a guinea pig model to control the progression of myopia. Experimental groups were administered 0.1% riboflavin solution with or without vitamin C by gavage from 3 days before myopic modeling and during the modeling process. Guinea pigs underwent 30 min of whole-body UVA irradiation after each gavage for 2 weeks. For control groups, guinea pigs were administered vitamin C and underwent either whole-body UVA irradiation without 0.1% riboflavin solution or whole-body fluorescent lamp irradiation with or without 0.1% riboflavin solution. Resultantly, myopia models were established with an increased axial length and myopic diopter. Compared with myopic eyes in the control groups, the net increase in axial length, diopter and strain assessment decreased significantly, and the net decrease in sclera thickness, ultimate load, and stress assessment decreased significantly in experimental groups. MMP-2 expression showed a lower net increase, while TIMP-2 expression showed a lower net decrease. In addition, hyperplasia of scleral fibroblasts was more active in myopic eyes of experimental groups. Overall, our results showed that oral administration of riboflavin with whole-body UVA irradiation could increase the strength and stiffness of sclera by altering the biochemical and biomechanical properties, and decreases in axial elongation and myopic diopter are greater in the guinea pig myopic model.

Effect of pharmacological pupil dilation on measurements and iol power calculation made using the new swept-source optical coherence tomography-based optical biometer.

PURPOSE: To determine whether pupil dilation affects biometric measurements and intraocular lens (IOL) power calculation made using the new swept-source optical coherence tomography-based optical biometer (IOLMaster 700©; Carl Zeiss Meditec, Jena, Germany). PROCEDURES: Eighty-one eyes of 81 patients evaluated for cataract surgery were prospectively examined using the IOLMaster 700© before and after pupil dilation with tropicamide 1%. The measurements made were: axial length (AL), central corneal thickness (CCT), aqueous chamber depth (ACD), lens thickness (LT), mean keratometry (MK), white-to-white distance (WTW) and pupil diameter (PD). Holladay II and SRK/T formulas were used to calculate IOL power. Agreement between measurement modes (with and without dilation) was assessed through intraclass correlation coefficients (ICC) and Bland-Altman plots. RESULTS: Mean patient age was 75.17±7.54 years (range: 57-92). Of the variables determined, CCT, ACD, LT and WTW varied significantly according to pupil dilation. Excellent intraobserver correlation was observed between measurements made before and after pupil dilation. Mean IOL power calculation using the Holladay 2 and SRK/T formulas were unmodified by pupil dilation. CONCLUSIONS: The use of pupil dilation produces statistical yet not clinically significant differences in some IOLMaster 700© measurements. However, it does not affect mean IOL power calculation.

Scleral Cross-linking Using Riboflavin and Ultraviolet-A Radiation for Prevention of Axial Myopia in a Rabbit Model.

Myopic individuals, especially those with severe myopia, are at higher-than-normal risk of cataract, glaucoma, retinal detachment and chorioretinal abnormalities. In addition, pathological myopia is a common irreversible cause of visual impairment and blindness. Our study demonstrates the effect of scleral crosslinking using riboflavin and ultraviolet-A radiation on the development of axial myopia in a rabbit model. The axial length of the eyeball was measured by A-scan ultrasound in New Zealand white rabbits aged 13 days (male and female). The eye then underwent 360° conjunctival peritomy with scleral crosslinking, followed by tarsorrhaphy. Axial elongation was induced in 13 day-old New Zealand rabbits by suturing their right eye eyelids (tarsorrhaphy). The eyes were divided into quadrants, and every quadrant had two scleral irradiation zones, each with an area of 0.2 cm² and a radius of 4 mm. Crosslinking was performed by dropping 0.1% dextran-free riboflavin-5-phosphate onto the irradiation zones 20 sec before ultraviolet-A irradiation and every 20 sec during the 200 sec irradiation time. UVA radiation (370 nm) was applied perpendicular to the sclera at 57 mW/cm² (total UVA light dose, 57 J/cm²). Tarsorrhaphies were removed on day 55, followed by repeated axial length measurements. This study demonstrates that scleral crosslinking with riboflavin and ultraviolet-A radiation effectively prevents occlusion-induced axial elongation in a rabbit model.

Scleral cross-linking by riboflavin and blue light application in young rabbits: damage threshold and eye growth inhibition.

BACKGROUND: Scleral cross-linking (SXL) by riboflavin and light application has been introduced as a possible treatment to increase scleral tissue stiffness and to inhibit excessive axial elongation of highly myopic eyes. We evaluated an ocular tissue damage threshold for blue light irradiation, and used SXL treatment to induce eye growth inhibition. METHODS: The sclera of 3-week-old rabbits (39 pigmented and 15 albino rabbits) were treated with different blue light intensities (450 ± 50 nm) and riboflavin. Alterations and a damage threshold were detected in ocular tissues by means of light microscopy and immunohistochemistry. The influence of SXL on the eye growth was examined in 21 young rabbits and was measured by using A-scan ultrasonography, micrometer caliper, and for selected eyes additionally by MR imaging. RESULTS: Light microscopic examinations demonstrated degenerative changes in ocular tissue after irradiation with blue light intensities above 400 mW/cm(2) (with and without riboflavin application). Therefore, that light intensity was defined as the damage threshold. Tissue alteration in retina, choroid, and sclera and activation of retinal microglia cells and Müller cells could be earlier observed at blue light intensities of 150 and 200 mW/cm(2). Albino rabbits were less sensitive to this SXL treatment. A significant reduction of the eye growth could be detected by SXL treatment with the minimal efficient blue light intensity of 15 mW/cm(2) and maintained stable for 24 weeks. CONCLUSIONS: SXL with riboflavin and blue light intensities below a defined damage threshold can induce a long lasting growth inhibitory effect on young rabbit eyes. Therefore, SXL might be a realistic approach to inhibit eye elongation in highly myopic eyes.

The effect of pupil dilation on AL-Scan biometric parameters.

The purpose of this study was to investigate the effects of pupil dilation on the parameters of the AL-Scan (Nidek Co., Ltd, Gamagori, Japan). We compared the measurements of axial length (AL), anterior chamber depth (ACD), central corneal keratometry reading, pupil diameter, and intraocular lens (IOL) power of 72 eyes of 72 healthy volunteers and patients scheduled for cataract surgery before and 45 min after instillation of cyclopentolate hydrochloride 1 % using the AL-Scan. Intraobserver repeatability was assessed by taking three consecutive recordings of ACD and AL. Only ACD readings were significantly different between predilation and postdilation (P < 0.001). The difference of the other measurements between two sessions was not statistically significant (P > 0.001). Only two cases in the study demonstrated changes in IOL power higher than 0.5 D. The intraobserver repeatability of both devices was good (CV values for ACD and AL were 0.16 and 0.20 %, respectively). Dilated pupil size did not affect the measurement of IOL power using the A-Scan optical biometer, but increase in ACD after dilation should be taken into account when performing refractive surgeries in which ACD is very important such as phakic anterior chamber IOL implantation.

Scleral cross-linking using riboflavin and ultraviolet-a radiation for prevention of progressive myopia in a rabbit model.

Our study demonstrates the effect of scleral cross-linking using riboflavin and ultraviolet-A radiation on the development of axial myopia in a rabbit model. Axial length of the eyeball was measured by A-scan ultrasound in 22 New Zealand white rabbits aged 13 days. The right eyes then underwent 360-degree conjunctival peritomy with (experimental group, n = 11) or without (control group, n = 11) scleral cross-linking, followed by tarsorrhaphy. The left eyes served as a control eye. In the experimental group, the right eyeballs were divided into quadrants, and every quadrant had either 2 (n = 8) or 6 (n = 3) scleral irradiation zones, each with an area of 0.2 cm² and radius of 4 mm. Cross-linking was performed by dropping 0.1% dextran-free riboflavin-5-phosphate onto the irradiation zones at 20 s before ultraviolet-A irradiation and every 20 s during the 200-s irradiation time. UVA radiation (370 nm) was applied perpendicular to the sclera at 57 mW/cm² (total UVA light dose, 57 J/cm²). Tarsorrhaphies were removed on day 55, followed by repeated axial-length measurement. In the control group, mean axial length in the right eyes increased from 10.50 ± 0.67 mm at baseline to 15.69 ± 0.39 mm 55 days later, for a mean change of 5.19 ± 0.85 mm. In the experimental group, corresponding values were 10.68 ± 0.74 mm and 14.29 ± 0.3 mm, for a mean change of 3.61 ± 0.76 mm. The between-group difference in the change in mean axial length was statistically significant (p < 0.001, Mann-Whitney nonparametric test). The present manuscript demonstrates that scleral cross-linking with riboflavin and ultraviolet-A radiation effectively prevents occlusion-induced axial elongation in a rabbit model.

Intravitreal injection of bevacizumab: changes in intraocular pressure related to ocular axial length.

PURPOSE: To evaluate the immediate and short-term effects of intravitreal injection of 1.25 mg/0.05 ml of bevacizumab on intraocular pressure related to different ocular axial lengths. DESIGN: A prospective case series of consecutive patients referred to the Department of Ophthalmology, San Pietro-Fatebenefratelli Hospital, from September 2011 through January 2011. METHODS: Twenty-five patients (10 men and 15 women, mean age 70.2 ± 8.98 years) scheduled for intravitreal injection of bevacizumab for the treatment of neovascular age-related macular degeneration were enrolled in this study. Axial length was measured preoperatively using IOLMaster. Intraocular pressure was measured before injection, after 1 min and after 15 min using Tono-Pen XL tonometry. RESULTS: The mean intraocular pressure change following the intravitreal bevacizumab injection was 21.92 ± 6.95 mmHg after 1 min and 6.24 ± 3.77 mmHg after 15 min. The mean axial length of the examined eyes was 23.2 ± 1.06 mm. A good correlation was observed between the axial length and intraocular pressure rise after both 1 (R (2) = 0.752, p < 0.001) and 15 min (R (2) = 0.559, p < 0.001). CONCLUSIONS: Patients undergoing intravitreal injection of 0.05 ml of bevacizumab can be exposed to intraocular pressure increases correlated to ocular axial length.

[Myopic CNV]. / Myope CNV.

Choroidal neovascularisation secondary to pathological myopia is the most common cause of severe visual impairment in myopic patients younger than 50 years old. The typical features of myopic CNV in contrast to age-related macular degeneration as well as the anatomic characteristics have an impact on the parameters of the baseline and follow-up examinations. As the usually small fibrovascular lesions show a rapid progression in the spontaneous course of the disease and lead to irreversible damage to the photoreceptors, prompt initiation of treatment is mandatory. The superior functional results of anti-VEGF drugs provide the reason for the first-line status of this treatment modality. Increasing safety data and consistent results of prospective pilot trials have proved photodynamic therapy to be inferior. There are signs that PRN-based treatment algorithms may allow for less frequent dosing than in other retinal diseases.

[Myopia update 2011]. / Myopie-Update 2011.

This review summarises some recent aspects of myopia research. The following conclusions have been drawn. As long as myopia progression is visually controlled, at least three different interventions are possible: (i) spectacles/contact lenses which correct only the centre of the visual field and leave the periphery somewhat myopic, (ii) outdoor activity or equivalent temporary increase in illuminance, (iii) pharmacological intervention of retinal growth signals that are transmitted to the underlying sclera. Options (i) and (ii) can be used without risks although there is still room for improvement of the variables. Option (iii) has re-entered a new phase of orientation with new searches for candidate targets after previous testing with muskarinic antagonists (pirenzepine) in children did not enter phase 3 level. If myopia is outside the range over which it is visually controlled by emmetropisation (in the case of high and pathological myopias), in principle the possibility exists to improve the mechanical stability of the sclera pharmacologically. However, there is still a need for more research. Up to now, the mechanical weakness of the sclera in highly mopyic eyes is surgically stabilised by "scleral buckling". However, these procedures have found limited acceptance since the effects were not very reliable. In 40 - 50 % of the cases of high myopia, degenerative processes are found in the retina which can be seen as consequence of the mechanical tension in the fundus, but may also be indepedent of this factor (no significant correlation with axial length!). In part they can be slowed down by intravitreal anti-VEGF therapy. A long-term study from Denmark has shown that most patients with myopia of between 6-9 dpt during puberty reach retirement age without disabling visual loss.

Effects of 7-methylxanthine on the sclera in form deprivation myopia in guinea pigs.

PURPOSE: The aim of this study was to determine the effect of the adenosine receptor antagonist 7-methylxanthine (7-MX) on form deprivation myopia in 3-week-old guinea pigs. METHODS: Two groups of 3-week-old guinea pigs were subjected to monocular deprivation (MD) using a diffuser and fed either 7-MX (300 mg/kg body weight; n = 7) or vehicle control (saline at an equal volume to 7-MX; n = 7). A control group (n = 6) was not subjected to form deprivation. Ocular refraction, axial length and body weight were measured at the start and after 21 days. The thickness of the posterior sclera was measured by light microscopy and the collagen fibril diameter in the inner, middle and outer layers of the sclera was measured by electron microscopy. RESULTS: In the vehicle control group, 21 days of MD produced significant amounts of myopia, axial elongation, thinning of the posterior sclera and thinning of the median collagen fibril diameter in the posterior sclera relative to the contralateral eyes. In the guinea pigs fed with 7-MX, however, form deprivation produced significantly less myopia and axial elongation compared with vehicle control animals. The 7-MX-treated animals exhibited a thickening of the posterior sclera in both the MD eye and the contralateral eye. In the 7-MX-treated animals, the median collagen fibril diameter in the posterior sclera was not reduced by form deprivation. CONCLUSIONS: Treatment with 7-MX appears to not only decrease the amount of myopia by around 50% and eliminate the eye elongation induced by form deprivation in guinea pigs, but also to prevent form deprivation myopia-related scleral changes, such as thinning of the sclera and thinning of the collagen fibril diameter in the posterior sclera.