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Purpose: Having previously demonstrated the efficacy of 0.01% atropine eye drops for inhibiting progression of childhood myopia, we conducted additional analyses to assess post-treatment changes in myopia progression., Study Design: Analysis of follow-up data from a previously reported randomized controlled trial METHODS: A mixed-effects model was used to compare intergroup changes in spherical equivalent (SE) and axial length (AL) at 1 month and 12 months after discontinuation of 2-year treatment with atropine or placebo in 167 school-age children., Results: Follow-up measurements were available for 149 participants at 1 month after discontinuation of treatment and for 51 participants at 12 months after discontinuation. At 1 month post-treatment, differences between the atropine and placebo groups in least squares (LS) mean changes in SE and AL, respectively, from 24 months were -0.06 diopters (D) (95% CI: -0.21, 0.08; P = .39) and 0.02 mm (95% CI: -0.05, 0.08; P = .60). At 12 months post-treatment, intergroup differences (atropine vs placebo) in LS mean changes in SE and AL, respectively, were -0.13 D (95% CI: -0.35, 0.10; P = .26) and -0.02 mm (95% CI: -0.12, 0.09; P = .75). LS mean changes in SE and AL from treatment discontinuation did not differ between the groups at 1 or 12 months post-treatment., Conclusion: Axial elongation was significantly less in the atropine group than in the placebo group. The suppression effect obtained at 2 years was maintained after 12 months. The absence of intergroup differences in myopia progression since treatment cessation suggests that myopic rebound did not occur., (© 2023. Japanese Ophthalmological Society.)

The evidence-basis based on existing myopia control trials along with the supporting academic literature were reviewed; this informed recommendations on the outcomes suggested from clinical trials aimed at slowing myopia progression to show the effectiveness of treatments and the impact on patients. These outcomes were classified as primary (refractive error and/or axial length), secondary (patient reported outcomes and treatment compliance), and exploratory (peripheral refraction, accommodative changes, ocular alignment, pupil size, outdoor activity/lighting levels, anterior and posterior segment imaging, and tissue biomechanics). The currently available instrumentation, which the literature has shown to best achieve the primary and secondary outcomes, was reviewed and critiqued. Issues relating to study design and patient selection were also identified. These findings and consensus from the International Myopia Institute members led to final recommendations to inform future instrumentation development and to guide clinical trial protocols.

Purpose: To investigate prospectively the characteristics in the higher-order aberrations and anterior segment tomography in patients with pathologic myopia., Methods: One hundred and twelve consecutive highly myopic patients (mean age 43.4 ± 9.3 years, spherical equivalent of refractive error ≥8 D and an axial length ≥26.5 mm) were studied. Thirty-seven emmetropic individuals (mean age 37.0 ± 14.5 years, spherical equivalent of refractive error ≤ ±1 D) were analyzed as controls. The ocular and cornea higher-order aberrations were measured using a Hartmann-Shack wavefront sensor (KR-1W; Topcon Corporation, Tokyo, Japan). The crystalline lens rise, the angle-to-angle, and the white-to-white values were measured using anterior segment OCT (SS-1000; Tomey Corporation, Nagoya, Japan). The mean curvature of the anterior corneal surface, the thickness at the thinnest central corneal point, the location of the central corneal point, the corneal volume, the anterior chamber volume, and the anterior chamber depth were measured using the Pentacam HR (Oculus, Inc., Wetzlar, Germany)., Results: The ocular total higher-order aberration for 4-mm pupil, the ocular spherical aberrations, and internal spherical aberration for 6-mm pupil were significantly higher in highly myopic eyes than in the emmetropic controls. The crystalline lens rise was significantly smaller in highly myopic eyes than in the emmetropic controls. The anterior chamber depth and the anterior chamber volume were significantly larger in highly myopic eyes than in the emmetropic controls., Conclusion: Highly myopic eyes had higher-order aberrations than emmetropic eyes because of the increasing internal aberrations.

Purpose: To investigate the serial changes of accommodation and spherical aberration in eyes with accommodative spasm., Methods: Four patients with accommodative spasm and ten healthy subjects were studied. The ocular refractive power (spherical equivalent) and spherical aberration were measured serially with an open-field, binocular Hartmann-Shack wavefront aberrometer. Patients and subjects wore full-correction lenses and were instructed to fixate a target set at 50 cm from the eye. The time-average of the refractive power, spherical aberration, and fluctuations of accommodation analyzed by the fast Fourier transform (FFT) of the two groups were compared., Results: The average ± standard deviation refractive power in the patients was significantly more negative than that in the healthy subject (-3.12 ± 1.06 vs. -1.49 ± 0.17 D). The integrated intensity of the FFT from 1 to 4 Hz was significantly higher in the patients than in the healthy subjects. The spherical aberration in patients was more negative than that in the healthy subjects (-0.033 ± 0.048 μm vs. 0.002 ± 0.027 μm)., Conclusions: Eyes with accommodative spasm are characterized by a lead of accommodation with greater fluctuations and negative spherical aberrations. Excessive accommodation can be measured objectively in such eyes with a binocular wavefront aberrometer without cycloplegics.

Purpose: To investigate the effect of the Optimized Aspheric Transition zone profile (OATz) that was devised to minimize the "red ring" in corneal topography on ocular higher order aberrations following LASIK for myopia., Methods: Laser in situ keratomileusis with OATz using the Nidek Advanced Vision Excimer Laser Platform (NAVEX) was performed on 22 eyes with a 4.5-mm optical zone and 8.0-mm transition zone (OATz group). Conventional LASIK was performed on 11 eyes with a 6.0-mm optical zone and 7.0-mm transition zone as a control (conventional group). The higher order aberrations for the central 6-mm diameter were measured at 1 month postoperatively using a Hartmann-Shack wavefront sensor. In addition to the spherical aberration, the magnitude and orientation of trefoil, coma, tetrafoil, and secondary astigmatism were compared between two groups using Zernike vector analysis., Results: The mean magnitude (root-mean-square) of the total higher order aberrations in the conventional group (0.70 +/- 0.28 microm) was significantly higher than that in the OATz group (0.51 +/- 0.15 microm, P < .05, unpaired t test). For spherical aberration, the OATz group had significantly lower values (0.22 +/- 0.17 microm) than the conventional group (0.38 +/- 0.23 pm, P < .05). The magnitude of coma in the conventional group was also higher than that in the OATz group (P < .05), and the mean axis of coma was 8.6 degrees in the conventional group and 64.3 degrees in the OATz group. No statistically significant differences were noted in the magnitude and axes of trefoil, tetrafoil, or secondary astigmatism between the two groups., Conclusions: The OATz profile may decrease the surgically induced increase of higher order aberrations, especially spherical aberration, following LASIK. However, a study with equivalent treatment groups and larger sample sizes is required for a definitive conclusion.

Purpose: To investigate the age-related changes in a myopic shift under binocular conditions (phoria myopia) in patients with intermittent exotropia (IXT)., Methods: Forty-five patients with IXT were studied: 21 were < or =9 years old (children), 11 were between 10 and 19 years (adolescents), and 13 were between 20 and 43 years (adults). The angle of strabismus was determined by the alternating prism cover test. The spherical refractive error was measured at 1 m using infrared video retinoscopy under monocular and binocular viewing conditions., Results: The change in the spherical refractive error (DeltaR) between binocular and monocular conditions was significantly larger in adults (DeltaR = -1.11 +/- 1.01 diopters (D), average +/- standard deviation) than in children (DeltaR = -0.34 +/- 0.34 D; P < 0.05, analysis of variance). DeltaR was significantly correlated with the angle of exotropia only in adults (r = 0.55, P = 0.04). After strabismus surgery, DeltaR decreased in adults (n = 3)., Conclusions: Because a significant myopic shift under binocular conditions was detected in IXT patients older than 20 years, phoria myopia can occur after age 20 even if functional disturbances are not observed in children or adolescent IXT patients, a fact that specialists need to bear in mind when treating younger patients.

Purpose: To determine the cone spacing in normal and myopic eyes from the images obtained by an adaptive optics (AO) fundus camera., Methods: Nineteen eyes of 19 healthy volunteers with a mean +/- SD spherical equivalent refractive error of -3.7 +/- 3.3 diopters (D) (range, -0.3 to -11.1 D) and a mean axial length of 25.4 +/- 1.61 mm (range, 23.4-28.0 mm) were investigated in a prospective cross-sectional study. An AO fundus camera equipped with a liquid crystal phase modulator was used to obtain the images of the photoreceptor mosaic. The spacing between the cones was calculated manually at a retinal locus 2 degrees temporal from the center of the fovea. The magnification of the image was calculated by the axial length measured with an IOL Master., Results: The axial length was correlated with the refractive error (Pearson, r = -0.869; P < 0.001). The average cone spacing in the moderate- to high-myopia group (-6.5 +/- 2.3 D, n = 9) was 4.71 +/- 0.44 microm, which was significantly greater (P = 0.002) than the 3.90 +/- 0.47 microm in the normal and low-myopia groups (-1.1 +/- 0.9 D, n = 10). The cone spacing was significantly correlated with the axial length (r = 0.77, P < 0.001)., Conclusions: The AO fundus camera is capable of acquiring images of the photoreceptors in normal and myopic eyes. The greater spacing between cones in the myopia group is consistent with histological findings. These results suggest that retinal expansion should be considered in addition to Knapp's law when aniseikonia is evaluated in axial myopia., ((c) Japanese Ophthalmological Society 2007)

Purpose: To investigate whether the type of posterior staphyloma (PS) affects the development of macular hole and retinal detachment (MHRD) in high myopia., Methods: Included in this retrospective study were 28 highly myopic eyes with MHRD (MHRD group) and 47 highly myopic eyes without MHRD (control group). The presence or absence of PS and the type of PS according to the classification of Curtin, the postoperative visual acuity, and the retinal reattachment rate were investigated., Results: The percentage of eyes with PS was significantly higher in the MHRD group than in the control group (P < 0.001). The rate of type II PS was significantly higher in the MHRD group (P = 0.01). There were no significant differences among the types of PS regarding the retinal reattachment rates and visual outcome., Conclusions: Eyes with type II PS have a higher risk for the development of MHRD. However, the type of PS did not seem to affect the anatomic and visual outcome.

Purpose: Myopic foveoschisis is common in high myopia. We report results of a pilot study of vitrectomy for patients with myopic foveoschisis., Design: Interventional case series., Methods: In an institutional setting five patients with high myopia (six eyes), and who had progressive visual impairment presumably due to myopic foveoschisis were studied. No eyes had a macular hole preoperatively based on optical coherence tomography (OCT). We performed vitrectomy including vitreous cortex removal, internal limiting membrane (ILM) peeling, and gas tamponade. Patients were followed for at least 6 months. Best-corrected visual acuity (BCVA), OCT. Scanning laser ophthalmoscope (SLO) microperimetry was examined in three eyes., Results: The foveal detachment resolved completely in five eyes and partially in one eye. No serious complications developed including macular hole formation or retinal detachment; BCVA improved more than two lines in all eyes (100%) 6 months postoperatively (P <.01); SLO microperimetry showed smaller scotoma compared with preoperatively and stabilized fixation., Conclusions: Vitrectomy with vitreous cortex removal, ILM peeling, and gas tamponade could be useful to treat myopic foveoschisis in highly myopic eyes. Because the natural course of the disease is not well-understood, further study should establish indications for this surgery.

Purpose: Macular holes cause retinal detachments in highly myopic eyes. Because degenerative macular changes often coexist, biomicroscopic evaluation of macular hole status after retinal reattachment is sometimes difficult. We studied macular holes with retinal detachment after vitrectomy using optical coherence tomography and evaluated the anatomic status of the hole and factors associated with anatomic success., Design: Retrospective, nonrandomized, comparative study., Patients: Sixteen eyes that underwent vitrectomy for retinal detachment associated with a macular hole were included. Internal limiting membrane peeling with indocyanine green was performed in 14 eyes; the epiretinal membrane was peeled with a diamond-dusted membrane scraper alone in two eyes. All retinas reattached postoperatively. The follow-up period at the optical coherence tomography examination was at least 6 months., Methods: Optical coherence tomography was performed vertically and horizontally, and the presence of a persistent macular hole was determined. Other information was obtained from patient records., Results: The macular holes closed in seven of 16 eyes (44%). Age, sex, axial length, preoperative best-corrected visual acuity, duration of symptoms, preoperative refractive error, and the preoperative area of the retinal detachment were not significantly correlated with hole closure. Improved postoperative best-corrected visual acuity (P <.05) was significantly associated with macular hole closure, and more frequent visual improvement (P =.06) was of borderline significance., Conclusions: The success rate was lower than those obtained in eyes without myopia or in myopic macular holes without retinal detachments. Macular hole closure may predict improved visual outcome for patients with retinal detachment and macular holes. Optical coherence tomography detects persistent macular holes in highly myopic eyes with retinal detachment.

The purpose was to compare the ocular higher-order aberrations and the visual performance between photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). Ocular aberrations and visual performance were measured after PRK in 26 eyes, after LASIK in 39 eyes, and in 29 normal myopic control eyes. Ocular aberrations were measured with a Hartmann-Shack aberrometer. Visual performance was evaluated with grating contrast sensitivity, high and low contrast visual acuity, and letter contrast sensitivity under full correction with spectacles. The results were that the root mean square (RMS) values of ocular higher-order aberrations after PRK or LASIK were significantly greater than that of normal controls for both 4-mm and 6-mm zones (PRK; 0.22 +/- 0.09 and 0.85 +/- 0.24 microm, LASIK; 0.20 +/- 0.06 and 0.82 +/- 0.24 microm, normal; 0.10 +/- 0.03 and 0.33 +/- 0.11 microm. P < 0.05 between PRK and normal, LASIK and normal, One Way ANOVA on Ranks). There were no significant differences between PRK and LASIK. The ocular higher-order aberrations increased in proportion with the attempted refractive correction by PRK and LASIK. The ocular higher-order aberrations correlated better with grating contrast sensitivity, low contrast visual acuity, and letter contrast sensitivity than with high contrast visual acuity. There was no difference among normal, PRK and LASIK in all the visual function tests, except between normal and PRK, or between normal and LASIK with letter contrast sensitivity. In conclusion, there was no difference in both ocular higher-order aberrations and visual performance between PRK and LASIK. The result suggests that surgeons can choose refractive procedures according to the corneal conditions or daily activities of patients.

Purpose: To study the effect of accommodation on ocular aberrations., Design: Observational case series., Methods: The ocular aberrations in 33 eyes of 33 young adults were measured with a Hartmann-Shack wavefront aberrometer before and during 3 diopters of accommodation., Results: The root mean square values of wavefront error did not change for a 4-mm and a 6-mm zone; however, spherical aberration changed significantly toward negativity for both the 4-mm zone (P <.001) and 6-mm zone (P =.022)., Conclusions: During accommodation, the significant change in spherical aberration occurs without a change of image quality. Therefore, for customized aberration, it may not be advantageous to eliminate the physiologic spherical aberration for far vision.

Objective: To assess the relation between magnitude of refractive correction and changes in higher order wavefront aberrations of the cornea after laser in situ keratomileusis., Design: Prospective, consecutive, nonrandomized comparative trial (self-controlled)., Participants: One hundred eyes of 53 patients with myopia (-2.0 to -13.0 diopters) were included., Intervention: Laser in situ keratomileusis was performed. Videokeratography measurements were conducted before and 1 month after surgery., Main Outcome Measures: The videokeratography data were used to calculate the higher order wavefront aberrations of the cornea for both small (3 mm) and large (6 mm) pupils., Results: For a 3-mm pupil, the surgery significantly increased coma-like (2.4 +/- 1.3-fold, P < 0.001, paired t test) and spherical-like (1.8 +/- 0.9-fold, P < 0.001) aberrations. For a 6-mm pupil, both coma-like (4.4 +/- 3.3-fold, P < 0.001) and spherical-like (9.4 +/- 5.2-fold, P < 0.001) aberrations were significantly increased by surgery. The amount of achieved correction showed significant correlations with the changes in coma-like (Pearson correlation coefficient r = 0.446, P < 0.001) and spherical-like (r = 0.348, P < 0.001) aberrations for a 3-mm pupil, and coma-like (r = 0.566, P < 0.001) and spherical-like (r = 0.693, P < 0.001) aberrations for a 6-mm pupil. The eyes that lost 2 or more lines of baseline spectacle-corrected visual acuity showed significantly larger induced increases in coma-like (P = 0.003, Mann-Whitney U test) and spherical-like (P = 0.009) aberrations for a 3-mm pupil than those that either improved or remained within 1 line of spectacle-corrected visual acuity, Conclusions: Laser in situ keratomileusis, performed using the current algorithms, increases higher order wavefront aberrations of the cornea, dependent on the amount of refractive correction.

Purpose: To determine local refractive changes and higher-order aberrations in patients with nuclear or cortical cataract., Setting: Osaka University Medical School, Osaka, Japan., Methods: Wavefront analysis of both ocular and corneal aberrations was performed with the Hartmann-Shack aberrometer in 2 patients, a 22-year-old woman with bilateral developmental nuclear cataract and a 68-year-old woman with mild bilateral cortical cataract., Results: Case 1 showed a delay in the wavefront that caused a myopic shift in the central pupillary area in both eyes, associated with the nuclear cataract. The spherical-like aberration (right eye, 36%; left eye, 21%) was greater than the coma-like aberration in both eyes. Case 2 showed an advancement of the wavefront that caused a hyperopic shift, especially in the lower temporal pupillary area, that was associated with the cortical cataract. The coma-like aberration (right eye, 63%; left eye, 52%) was greater than the spherical-like aberration in both eyes. The polarity of the third-order spherical aberration was negative in Case 1 and positive in Case 2. Corneal higher-order aberrations were small and had a different distribution than ocular higher-order aberrations in both patients., Conclusions: The Hartmann-Shack aberrometer was useful in detecting local refractive changes and higher-order aberrations in patients with mild cataract. The polarity and the absolute value of ocular higher-order aberrations may be useful parameters to characterize eyes with cataract.

Purpose: It has still not been determined whether the retinal mechanism causing form-deprivation myopia (FDM) is different from that causing lens-induced myopia (LIM). We previously reported that FDM was blocked by an intravitreal injection of the nitric oxide (NO) synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME). In this study, we investigated the effect of L-NAME on LIM in chicks., Method: The left eyes of 6-day-old chicks were injected with 30 microl of nontoxic concentrations of L-NAME (< or = 360 mM) or saline. The right eyes were injected with 30 microl of saline. A -16 dpt lens was placed in front of the left eye for 6 days. Another group of 6 chicks were injected with 180 mM L-NAME (left eye) and with saline (right eye) before placing -16 dpt lenses in front of both eyes. After removing the lens, the refraction and the axial length were measured. The effect of L-NAME (180 mM) on the retina of a separate group of chicks was examined by electroretinography 60 min after an intravitreal injection in non-LIM-treated eyes., Results: The eyes of chicks that were injected with 180 or 360 mM L-NAME were less myopic and had significantly shorter axial lengths than control eyes. A significant decrease of the On response and an increase of the Off response were observed., Conclusion: The injection of L-NAME into developing chick eyes that were then covered with a -16 dpt lens resulted in a modifications of retinal function and an inhibition of the development of myopia. These results, combined with the earlier findings, suggest that NO modulates a common retinal pathway that leads to both LIM and FDM., (Copyright 2001 S. Karger AG, Basel.)

Purpose: To assess functional and anatomical outcomes after foveal translocation with 360-degree retinotomy and simultaneous torsional muscle surgery in patients with myopic neovascular maculopathy., Methods: Foveal translocation with 360-degree retinotomy was performed in 11 eyes of 11 patients with myopic neovascular maculopathy. Ten eyes had simultaneous torsional muscle surgery with recession of the superior oblique muscle and tucking of the inferior oblique muscle. Silicone oil removal with or without intraocular lens implantation was performed 2 to 8 weeks after the primary procedure. Visual acuity, binocular function, and degree of cyclotorsion were assessed preoperatively and postoperatively. Angles of retinal and globe rotation, distance of foveal shift, and surgical complications were also investigated., Results: With a mean postoperative follow-up of 6.2 months (range, 3 to 13 months), vision improved (greater than 0.2 logarithm of minimal angle of resolution [logMAR] units) in eight eyes, was unchanged in two eyes, and worsened (greater than 0.2 logMAR units) in 1 eye. Seven of 11 eyes (64%) had a final visual acuity of 20/50 or better. Five patients developed or maintained binocular fusion, four patients continued to have suppression, and two patients developed diplopia that was managed by spectacles with Fresnel prisms. Subjective cyclotorsion was less than 8 degrees in 10 eyes. Mean retinal and globe rotations were 23.4 degrees and 19.8 degrees, respectively. Average size of the choroidal neovascular membrane was 0.8 disk diameter, whereas the average distance of foveal shift was 1.5 disk diameter. After the primary procedure, three eyes developed retinal detachment, one eye macular hole, and one eye proliferative vitreoretinopathy. These complications were successfully managed by additional surgery., Conclusion: Foveal translocation with 360-degree retinotomy is effective in restoring vision in some patients with myopic neovascular maculopathy. Although the development of torsional diplopia is generally obviated by simultaneous extraocular muscle surgery, a relatively high incidence of surgical complications should be taken into account with this procedure.

Purpose: To compare the visual outcome after foveal translocation by scleral shortening and that after 360 degrees retinotomy with extraocular muscle surgery in a patient with bilateral myopic neovascular maculopathy., Methods: Case report., Results: A 52-year-old woman with bilateral myopic neovascular maculopathy underwent foveal translocation with scleral shortening in the left eye, and visual acuity improved from 20/70 to 20/30. However, choroidal neovascularization recurred, and the final visual acuity was 20/40 after excision of the choroidal neovascularization. Foveal translocation with 360 degrees retinotomy was performed on the right eye, and visual acuity improved from 20/150 to 20/30. The critical print size was better, and the retinal sensitive area was larger in the right eye., Conclusion: The better reading ability shown by foveal translocation by a 360 degrees retinotomy compared with scleral shortening may stem from a larger retinal sensitive area obtained by this method.

Purpose: To document the visual outcome after successful foveal translocation with intentional retinal detachment and scleral shortening for the treatment of myopic neovascular maculopathy., Methods: Two severely myopic patients with subfoveal neovascular membranes underwent surgical translocation of the fovea to an area of healthy retinal pigment epithelium by means of scleral shortening and intentional retinal detachment. In the postoperative period, monocular and binocular visual function were studied., Results: In one patient, best-corrected visual acuity improved from 20/150 to 20/20 postoperatively. In the second patient, acuity initially improved from 20/70 to 20/30. In both patients, the fixation point shifted from the site of the neovascular membrane. Oblique astigmatism developed and was managed with hard contact lenses. Diplopia and subjective torsion occurred transiently. Micropsia occurred in one patient. Peripheral fusion assessed by Worth four-dot testing after resolution of diplopia disclosed suppression in the nondominant eye in both cases., Conclusions: Foveal translocation with intentional retinal detachment and scleral shortening was useful in improving visual acuity in two patients with myopic neovascular maculopathy. Diplopia and aniseikonia occurred but resolved over time as suppression developed. This technique is promising for patients with myopic neovascular maculopathy.

Purpose: Form-deprivation myopia (FDM) is believed to result principally from actions of substances that modulate information processing in the retina. We used a chick model to investigate what role nitric oxide (NO), a gaseous neuromodulator, might play in the development of FDM., Methods: We injected different concentrations of the NO synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) (30 ml) into the left eyes and the same volume of saline into the right eyes of 6-day-old chicks. Both eyes of most chicks were occluded for 6 days with translucent goggles. After removal of the goggles, the refraction was measured by retinoscopy and the axial lengths with an A-mode ultrasound. In some chicks we measured the concentration of NOx (nitrite and nitrate) in the retina. A few chicks, not wearing occluders after injection of L-NAME and saline, ERG and refraction, were examined 6 days after the treatment., Results: In chicks that wore occluders, refractive error and axial length were significantly less affected in eyes injected with L-NAME (180, 360, or 540 mM) compared to control (right) eyes. ERG changes were reversible, except in eyes injected with the highest concentration (540 mM) of L-NAME. The eyes of chicks, injected with L-NAME and reared without occlusion, had normal refractive values. After 6 days of form deprivation, the concentration of NOx in the retina of eyes injected with L-NAME (180 mM) was significantly less than the concentration in eyes injected with saline., Conclusions: The injection of L-NAME before occlusion of developing chick eyes leads to reversible modifications in retinal function and inhibits the development of form-deprivation myopia.

Background: The retina is known to be involved in the development of form-deprivation myopia (FDM); however, it is not clear whether the retinal changes that lead to lens-induced myopia (LIM) are the same as those involved in FDM. To gain insight into the retinal mechanism(s) that cause myopia, we investigated differences in the results of electroretinography (ERG) in eyes with FDM and LIM., Methods: LIM or FDM was induced in chick eyes by placing various powers of spectacles or an occluder over the left eyes of 6-day-old chicks. After 6 days, the spectacles or occluder was removed, refraction and axial length were measured and ERG was performed. Results for eyes treated with spectacles and those treated with occluders were compared., Results: Refraction and axial length changed concomitant with the power of the lens used, but components of the ERG of eyes with LIM were not related to the power of lens added. Refraction and axial lengths of eyes covered with a -16 D lens did not differ from these values in eyes covered with an occluder. The a- and b-waves were also similar for the two groups. However, oscillatory potentials decreased significantly in the chicks with FDM., Conclusions: Retinal function differs in LIM and FDM, as indicated by differences in the oscillatory potentials. This difference may stem from the fact that in FDM the retinal image is continuously defocused, whereas images are ultimately focused on the retina in LIM.

Chick eyes occluded for various periods or treated with various concentrations of kainic acid (KA) or 2-amino-4-phosphonobutylate (APB) during development showed characteristic changes of electroretinography and of refraction. In occluded eyes, oscillatory potential amplitudes (OP-A) were reduced, even with high-intensity stimulation, in proportion to duration of occlusion, but b wave amplitude was unchanged, implying functional changes in inner layers of the deprived retina. OP-A reduction after only 1 week of occlusion and reversibility of this change might reflect retinal changes preceding axial elongation. KA was confirmed to induce myopia with axial elongation and APB to induce hyperopia with axial shortening. KA and APB both suppressed OP-A. KA reduced ON and OFF responses, but low-dose APB suppressed only ON responses. Study results suggest that myopia could be induced by changes of inner retina mediating OP attenuation and degradation of ON and OFF responses. This manuscript reports unpublished work that is not currently under consideration for publication elsewhere.