Immunologic assessment and KMT2D mutation detection in Kabuki syndrome.

Kabuki or Niikawa-Kuroki syndrome (KS) is a rare disorder with multiple malformations and recurrent infections, especially otitis media. This study aimed to investigate the genetic defects in Kabuki syndrome and determine if immune status is related to recurrent otitis media. Fourteen patients from 12 unrelated families were enrolled in the 9-year study period (2005-2013). All had Kabuki faces, cleft palate, developmental delay, mental retardation, and the short fifth finger. Recurrent otitis media (12/14) and hearing impairment (8/14) were also more common features. Immunologic analysis revealed lower memory CD19+ cells (11/13), lower memory CD4+ cells (8/13), undetectable anti-HBs antibodies (7/13), and antibody deficiency (7/13), including lower IgA (4), IgG (2), and IgG2 (1). Naïve emigrant lymphocytes, lymphocyte proliferation function, complement activity, and superoxide production in polymorphonuclear cells were all normal. All the patients had KMT2D mutations and 10 novel mutations of R1252X, R1757X,Y1998C, P2550R fs2604X, Q4013X, G5379X, E5425K, R5432X, R5432W, and R5500W. Resembling the phenotype of common variable immunodeficiency, KS patients with antibody deficiency, decreased memory cells, and poor vaccine response increased susceptibility to recurrent otitis media. Large-scale prospective studies are warranted to determine if regular immunoglobulin supplementation decreases the frequency of otitis media and severity of hearing impairment.

Visual outcomes for high myopic patients with or without myopic maculopathy: a 10 year follow up study.

AIM: To evaluate the visual outcomes for high myopic patients aged 40 years and older with or without myopic maculopathy. METHODS: 552 high myopic (spherical equivalent < or =-6.0D or axial length > or =26.5 mm) patients were enrolled in the study, 230 cases with myopic maculopathy (at least lacquer cracks were identified) and 322 cases without maculopathy. The initial and final visual acuity (VA) (after 10 years) was compared between two groups. Additionally, the relation between sex, age, refraction, and axial length was analysed to find out the possible risk factors associated with visual outcome in myopic maculopathy. RESULTS: In 92% of patients aged 40-49, final VA was better than 20/40 after 10 years of follow up. However, it was less than 40% in those older than 60 years. For more than 50% of patients older than 40 years of age with maculopathy, their vision had decreased more than two lines in Snellen VA after 10 years of follow up, compared to only 4.3% of analogues without myopic maculopathy. Patchy atrophy and choroidal neovascularisation in myopic macular degeneration groups showed poorer visual outcome than lacquer cracks in the macular lesion group. Other prognostic factors of visual outcomes were myopic refraction, axial length, and ageing. CONCLUSIONS: Clearly, prognosis for patients with maculopathy is poorer than for those without maculopathy. Refractive status, axial length, and ageing are the main factors involved in determining the visual outcomes. The macular grading also affects the visual outcome for high myopic patients.

Innervation of orbital and choroidal blood vessels by the pterygopalatine ganglion in pigeons.

Orbital and choroidal blood vessels in mammals are known to receive a parasympathetic innervation from the pterygopalatine ganglion, which appears to utilize vasoactive intestinal polypeptide (VIP) and nitric oxide (NO) to increase choroidal blood flow. The present studies were undertaken to elucidate the anatomical and neurotransmitter organization of the pterygopalatine ganglion input to orbital and choroidal blood vessels in pigeons. Single- or double-label immunohistochemistry were employed on paraformaldehyde-fixed cryostat sections of the pigeon eye and surrounding orbital tissue to localize 1) VIP+ neurons and fibers; 2) choline acetyltransferase (CHAT)-containing cholinergic neurons and fibers; 3) axons containing the 3A10 neurofilament-associated antigen; and 4) neuronal NO synthase (nNOS)-containing neurons and fibers. NOS+ neurons and fibers were also identified by NADPH-diaphorase histochemistry in sections and whole-mount specimens. The pterygopalatine ganglion was found to consist of an interconnected series of three to four main microganglia of about 50-200 neurons each and numerous lesser microganglia. The major microganglia of the pterygopalatine network in pigeon lie along the superior aspect of the Harderian gland, with many additional fibers and microganglia of the network encircling the gland. Neurons of all microganglia were extremely rich in VIP, nNOS, and NADPH-diaphorase and moderate in CHAT. The majority of the pterygopalatine ganglion neurons were observed to co-contain VIP and nNOS. Axons labeled for VIP, nNOS, NADPH-diaphorase, or the 3A10 antigen could be traced from the pterygopalatine ganglion network to perivascular fiber plexi on orbital blood vessels. These orbital vessels, many of which enter the choroid posteriorly and nasally, appear to be a conduit by which pterygopalatine postganglionic fibers reach the choroid. The pterygopalatine postganglionic fibers were also seen to innervate the Harderian gland and contribute branches to the nearby ophthalmic nerve. Within the choroid, VIP+ fibers were widely scattered and sparse but were most abundant in nasal choroid. A few VIP+ and NADPH- diaphorase+ neurons were also observed in the choroid. These results suggest that pterygopalatine ganglion neurons of birds use VIP and NO to exert vasodilatory control over blood flow to and within the avian choroid.

The effects of choroidal or ciliary nerve transection on myopic eye growth induced by goggles.

PURPOSE: To determine the role of the choroidal and ciliary nerves and the functions they control, choroidal blood flow (CBF) and accommodation-pupil diameter, respectively, in myopia induced by form-vision deprivation. METHODS: Three groups of chicks were studied: chicks with choroidal nerves cut in the right eye, chicks with ciliary nerves cut in the right eye, and sham control chicks that received the same surgical preparation but no nerve cuts. A plastic, dome-shaped goggle was glued over the right eye of birds in all three groups after orbital surgery, and, 2 weeks later, CBF was measured using laser Doppler flowmetry. Refractive status was then measured using streak retinoscopy, and axial, nasotemporal, and dorsoventral lengths were measured using vernier calipers after enucleation. The eyes were also weighed. RESULTS: In the sham control birds, considerable ocular enlargement in all dimensions and a high degree of myopia (-14.68 diopters) was observed in the goggled eye, and CBF in the goggled eye was 66% of that in the nongoggled eye. In birds with choroidal nerve cuts, the degree of enlargement of the goggled eye was less in all dimensions, and the myopia in the goggled eye (-4.74 D) was attenuated compared to that observed in the sham controls. CBF in the goggled eye was 21% of that in nongoggled eye. Finally, in the birds with ciliary nerve cuts, nasotemporal and dorsoventral enlargement of the goggled eye were similar to that in the shams, but the axial elongation and the degree of myopia (-9.57 D) were less than observed in sham control eyes. As in the shams, CBF in the goggled eye was reduced to 59% of that in the nongoggled eye. CONCLUSIONS: These results show that although elimination of accommodation and severe reductions in CBF do affect eye growth (the latter more so), they do not prevent form-vision deprivation-induced myopia. Thus, either the mechanism of visual deprivation-induced myopia is different from that in idiopathic human myopia, or CBF levels and accommodation do not play a major role in either.

The relationship of choroidal blood flow and accommodation to the control of ocular growth.

We have carried out a number of different studies in chicks to examine the relationship between choroidal blood flow and myopic eye growth, and between accommodation and myopic eye growth. Our studies on choroidal blood flow show that myopic eye growth produced by form vision degradation leads to dramatic reductions in choroidal blood flow. These reductions appear directly attributable to the eye enlargement and the reduction in choroidal blood flow does not appear to be permissive for eye growth, since experimentally reduced choroidal blood flow hinders eye growth. Choroidal blood flow that is slightly above normal, however, may slightly enhance eye growth. Our studies on accommodation do not reveal any major necessary role of accommodation in regulating normal growth or in form vision degradation induced myopic eye growth. We found preliminary evidence, however, that chronically stimulating accommodation over a 2 week period, thereby producing excessive time in accommodation, may be sufficient for yielding a small but significant degree of myopic refractive error. Our studies suggest that neither fluctuations in choroidal blood flow nor an intact accommodative apparatus are essential for normal eye growth or myopic eye growth produced by form deprivation. Further studies are needed to confirm that excessive time in accommodation might be sufficient for producing myopia. Finally, our finding that choroidal blood flow is substantially reduced in myopic eyes may have implications for the etiology of the retinal problems suffered by humans with moderate to severe myopia.

The cornea in young myopic adults.

AIMS: To further understand the effect of refractive error on the corneal dimensions and function. METHODS: Corneal curvature, corneal thickness, and axial length measurements were performed, as well as specular microscopy and fluorophotometry, on patients with various refractive statuses. 216 subjects, mean age 22.2 (SD 4.2) years, were examined. Patients with previous contact lens wear history, external eye diseases, as well as previous ocular surgeries, were excluded. RESULTS: The corneas were flatter in eyes with longer axial length (r = -0.22, p = 0.003). Eyes with more myopic spherical equivalent had longer axial length (r = -0.90, p <0.001) as well as less corneal endothelial density (r = 0.20, p = 0.037). Corneal endothelial density decreased in eyes with longer axial length (r = 0.24, p = 0.019); however, it correlated neither with corneal thickness (r = -0.06, p = 0.59) nor with corneal curvature (r = -0.07, p = 0.52). The corneas had a mean corneal thickness of 533 (SD 29) microm and were thinner in more myopic eyes (r = 0.16, p = 0.021). The corneas tended to be thinner in eyes with longer axial length. However, the correlation did not reach statistical significance (r = -0.11, p = 0.14). Besides, there was no significant correlation between the corneal thickness and the corneal curvature (r = -0.13, p = 0.093) and the endothelial permeability (r = 0.042, p = 0.69). The corneas with higher endothelial density had larger corneal transfer coefficient (r = 0.26, p = 0.024) and higher permeability to fluorescein molecules (r = 0.28, p = 0.014). Nevertheless, the corneal endothelial permeability did not correlate significantly with either the axial length (r = -0.18, p = 0.11) or the degree of myopia (r = 0.12, p = 0.26). CONCLUSION: Changes in the anterior segments as the eyeball elongates in myopia progression included flatter corneal curvature, decreased corneal thickness, as well as decreased endothelial density. These factors should be considered in refractive surgery.

Distribution within the choroid of cholinergic nerve fibers from the ciliary ganglion in pigeons.

The distribution of the ciliary ganglion (CG) innervation to the pigeon choroid was determined immunohistochemically, using antisera against choline acetyltransferase (CHAT) and a neurofilament-related protein (the 3A10 antigen). Single-labeling revealed that the nerve fibers containing these two antigens were similarly distributed in the pigeon choroid, with the superior and temporal quadrants of the eye containing the most fibers. Both types of fibers surrounded and ramified on choroidal blood vessels. Additionally, CHAT+ varicosities were evident among vessels in the choroid and choriocapillaris. Double-label immunofluorescence revealed that CHAT and the 3A10 antigen were almost completely colocalized in choroidal nerve fibers, but absent from CHAT+ varicosities. Substance P-containing and calcitonin gene-related peptide-containing choroidal nerve fibers were poor in 3A10+ labeling. Transection of the postganglionic fibers of the CG reduced CHAT+ and 3A10+ nerve fibers in the choroid to 3-5% of normal abundance, with most of the residual fibers being located in the nasal and inferior quadrants. The present results suggest that the CG in pigeon preferentially influences choroidal blood flow in the superior and temporal parts of the eye, which are involved in high acuity and binocular vision.

Choroidal blood flow is reduced in chicks with ocular enlargement induced by corneal incisions.

We have previously reported decreased choroidal blood flow (CBF) associated with goggle-induced ocular enlargement and myopia. It was uncertain, however, if this change in CBF was related to the occurrence of ocular enlargement or the increased ocular temperature produced by the goggle. We therefore used corneal surgery-induced ocular enlargement that eliminated the thermal effects observed with goggles to investigate the effects of ocular enlargement on CBF. Central corneal incisions (2 mm in length) were made in the right eye of 4 day old chicks and the wound sutured. In one group, the incision was oriented along the vertical meridian (with the head in its natural position -beak tip 30-45 degrees below horizontal), while in another group the incision was oriented along the horizontal meridian (with the head in its natural position). Age matched controls received no corneal incision. Two weeks later, CBF was measured using laser Doppler velocimetry. After determining CBF, the eyes were removed and axial length, nasotemporal length and dorsoventral length were measured. Ocular enlargement was induced in 11 out of 12 chicks with vertical cuts. The CBF in the operated eye of these 11 animals was 62% of that in the nonoperated eye. Ocular enlargement was also induced in eight of 14 chicks with horizontal cuts. The CBF in the operated eye in these eight chicks was 60% of that in the nonoperated eye. The extent of eye growth was greater in all dimensions in the vertical cut chicks with ocular enlargement than in the horizontal cut chicks with ocular enlargement.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduction in choroidal blood flow occurs in chicks wearing goggles that induce eye growth toward myopia.

Goggles that degrade the retinal image produce axial enlargement of the ocular globe and large myopic refractive errors. Many authors have assumed that visual image degradation itself leads to myopia. Hodos and co-authors have shown, however, that goggled eyes in chicks are considerably warmer than normal. Such temperature changes may either underlie or be a consequence of alterations in choroidal blood flow (CBF). Since alterations in CBF could affect eye growth, we explored the effect of monocular goggling on CBF in chicks. Plastic goggles were glued over one eye in four-day old chicks and the goggles were left in place for 12 or 14 days. Fourteen days after the goggling, CBF was measured using laser Doppler velocimetry. Three groups of chicks were studied: 1) chicks with goggles for 14 days; 2) chicks with goggles for 12 days followed by no goggles for the two days; 3) age matched non-goggled chicks. A -scan ultrasonography confirmed that the visual deprivation produced vitreous chamber elongation in the goggled eye and that the degree of elongation for the goggled eye was the same for the two goggled groups. The results were: 1) blood flow in non-goggled chicks was similar in both eyes; 2) blood flow was significantly reduced in the goggled eye in chicks wearing goggles for 14 days- 37% of control; and 3) blood flow was still significantly reduced in the goggled eye in chicks whose goggles were removed two days before measurement- 51% of control. These results show that CBF is reduced by goggles that result in myopic eye growth.(ABSTRACT TRUNCATED AT 250 WORDS)

The effectiveness of 0.5% atropine in controlling high myopia in children.

Twenty highly myopic children (> or = -6.0 D) were treated with 0.5% atropine eyedrops once per night. Twelve subjects were initially treated with a short-acting cycloplegic agent, tropicamide (0.5%) (Group A), and the other eight subjects did not receive any myopic therapy before atropine (Group B). These cases were followed for up to five years. In Group A, the mean myopic progression rate after 0.5% atropine treatment was -0.01 +/- 0.04 D/M (Diopter/Month), which was significantly lower than that of the period during tropicamide treatment (-0.12 +/- 0.09 D/M) (p < 0.05). In Group B, the mean myopic progression rate after atropine therapy was begun was -0.04 +/- 0.06 D/M, which was also significantly slower than that of non-medication, -0.14 +/- 0.07 D/M (p < 0.05). The results suggested that 0.5% atropine is effective for slowing down myopic progression, even in highly myopic children.

The effect of 0.5% timolol maleate on the ocular perfusion of ocular hypertensive patients by scanning laser flowmetry.

To understand the effect of 0.5% timolol maleate on the ocular perfusion of the optic disc and macula in ocular hypertensive patients, we enrolled 10 males and 15 females without any systemic or ocular disease, except intraocular pressure higher than 20 mmHg. Their average age was 33 +/- 13 y/o (range 14-45). Under the randomized, double-masked design, one drop of 0.5% timolol maleate was given in one eye, and placebo in the fellow eye. Heart rate, blood pressure, intraocular pressure, and ocular perfusion were measured at baseline, and then 30 minutes and 2 hours after treatment. Ocular perfusion was measured by Heidelberg Retina Flowmeter (Heidelberg Engineering GmbH, Heidelberg, Germany). We used 10 degrees measurement field and 10 x 10 pixels measurement frame. Four areas were measured, i.e., temporal upper, temporal lower, and nasal parts of the optic disc, and macula. In comparison to the baseline, the treated eyes had a slight reduction of blood flow, volume, and velocity 30 minutes after treatment, but these parameters came back close to the baseline value at 2 hours after treatment. Similar changes were also noted in the control eyes. The results showed that a single drop of 0.5% timolol had minimal effects on the retinal and macular circulation within 2 hours after treatment.

The choroidal blood flow response after flicker stimulation in chicks.

Form-deprivation myopia (FDM) can be prevented by exposing the animal to stroboscopic illumination (10 Hz). Flicker illumination is known to stimulate the release of dopamine (DA) from the retina. We hypothesize that DA was released and diffused into the choroid. To prove this hypothesis, we decided to undertake an investigation in chicks and measure choroidal blood flow (ChBF) during stimulation of the ocular fundus with diffuse flicker. White Leghorn chicks (2 weeks old) were used for this study. Different flash stimulations (5 Hz approximately 50 Hz) were given for 3 minutes, then ChBF was recorded with the PeriFlux flowmeter simultaneously and continuously for 5 minutes. Some birds are recorded up to 120 minutes to find out any late-onset effect. The ChBF was increased after flicker stimulation. The difference was statistically significant in 10 Hz, 20 Hz, and 30 Hz. The ChBF can maintain 20% higher for 60 minutes. Therefore, flicker illumination preventing FDM may be induced by the hyperactivity of ganglion cells, then stimulates the release of DA from the retina and suppresses the development of myopia.

The regulation of the scleral growth associated with deprivation myopia in chicks.

The mechanism of axial elongation caused by experimental or clinical myopia is still unknown. We sought to explore the changes of scleral chondrocytes during myopia formation through the cell biology model. White Leghorn chicks were used for this study. The right eye was covered with a translucent goggle after hatching, and the left eye was left uncovered for control. The chicks were maintained on 12 hours light-dark cycle for two weeks, then sacrificed every other day and the eyeballs removed for study. Our results in the primary culture of scleral chondrocytes showed that the densities of chondrocytes on myopic eyes were significantly higher than those of the controlled non-myopic eyes, and 3H-thymidine incorporation rate also increased with the increasing of the concentration of fetal bovine serum. The PCNA index of chondrocytes in myopic eyes was also higher than that of the controlled non-myopic eyes. Thus, axial elongation of experimental myopia in the chick is the result of active tissue remodeling rather than passive scleral stretching alone.

The cycloplegic effects of cyclopentolate and tropicamide on myopic children.

Thirty-seven myopic children were given either 1-2 drops of 1% cyclopentolate or 1% tropicamide twice with 5 min intervals to evaluate the time course and maximal cycloplegic effect of both agents. The other fifteen subjects were given 1% tropicamide initially, then 1% cyclopentolate given after 30 min of maximal effect of tropicamide appeared to evaluate whether the effect of cyclopentolate was superior to tropicamide. Cycloplegic refraction was measured with an auto-refractometer (Topcon RK-3000) before drug delivery and every 15 min thereafter, for 90 min. The maximal cycloplegic effect of cyclopentolate was around 45 min, then it remained stable until 90 min after the last instillation. The effect of tropicamide was faster than that of cyclopentolate. It was around 30 min, then it stabilized until 75 min. The extra effect of cyclopentolate over tropicamide was minimal (only -0.1D). The power of cornea and astigmatism were not affected by either agent. However, a big variation in astigmatism was noted during the course, especially with cyclopentolate. This study suggests that 1% tropicamide should be a good agent for routine refractive status checking on myopic children.

The effect of intravitreal injection of atropine on the proliferation of scleral chondrocyte in vivo.

Atropine was found to be effective in arresting the progression of myopia. However, the actual mechanism is still unclear. Thus, we tried to investigate the in vivo effect of atropine on the proliferation of scleral chondrocytes in chicks of form-deprivation myopia. Twenty chicks were equally divided into 4 groups which included intravitreal injection of normal saline (IVN), IVN with goggling (IVNG), intravitreal injection of atropine (1%) (IVA), and IVA with goggling (IVAG) groups. Intravenous injection of bromodeoxyuridine (BrdU) (30 mg/kg) from subaxillary vein was performed 2 hours before being sacrificed. The eyeballs were then fixed in 10% neutral-buffered formalin at 4 degrees C. Standard BrdU immunohistochemical staining was performed. The BrdU labeling index was obtained from the average of positive labelings of BrdU in scleral chondrocytes for every 100 counting cells in posterior poles and anterior scleral margins by two experienced technicians. The BrdU index on the anterior scleral margin of the IVAG group was less than that of the IVNG group. The index on the anterior scleral margin of the IVNG group was higher than the IVN group. Although the index on the posterior poles of the IVNG group was also higher than the IVN group, it was statistically not different. Also, no statistical difference was found between IVN and IVA on the anterior scleral margins or posterior poles. The index was significantly different on the anterior scleral margins, but not on the posterior pole among each group. Therefore, intravitreal injection of atropine could inhibit the proliferation of chondrocytes on the anterior margins of sclera, but not the posterior poles in form-deprivation myopia.

Effects of different concentrations of atropine on controlling myopia in myopic children.

Although 1% atropine effectively slows myopia progression, it is associated with adverse effects, including photophobia, blurred near vision, and poor compliance. We investigated whether lower doses of atropine would control myopia progression. One hundred and eighty-six children, from 6 to 13 years of age, were treated each night with different concentrations of atropine eye drops or a control treatment for up to 2 years. The mean myopic progression in each of the groups was 0.04 +/-0.63 diopter per year (D/Y) in the 0.5% atropine group, 0.45+/-0.55 D/Y in the 0.25% atropine group, and 0.47+/-0.91 D/Y in the 0.1% atropine group. All atropine groups showed significantly less myopic progression than the control group (1.06+/-0.61 D/Y) (p<0.01). Our study also showed that 61% of students in the 0.5% atropine group, 49% in the 0.25% atropine group and 42% in the 0.1% atropine group had no myopic progression. However, 4% of children in the 0.5% atropine group, 17% in the 0.25% atropine group, and 33% in the 0.1% atropine group still had fast myopic progression (>-1.0 D/Y). In contrast, only 8% of the control group showed no myopic progression and 44% had fast myopic progression. These results suggest that all three concentrations of atropine had significant effects on controlling myopia; however, treatment with 0.5% atropine was the most effective.

Influence of destruction of retina-RPE complex on the proliferation of scleral chondrocytes in chicks.

We studied the role of the retina-retinal pigment epithelium (RPE) complex in the proliferation of scleral chondrocytes in chicks. Seventy-two chicks were allocated to one of four groups: intravitreal gentamicin (400 microg) injection (destruction of retina-RPE complex); intravitreal gentamicin injection with goggling; goggling only (form-deprivation myopia); and intravitreal saline injection (control). The chicks were killed and retina-RPE complexes were harvested under a microscope. Retina-RPE complexes were then co-cultured with primary culture of first day scleral chondrocytes in Transwell-COL co-culture systems (Costar), with two different pore sizes (0.4 and 3.0 microm) and serum-deprivation medium. An MTT assay was performed at A550 after 4 days. In the 0.4 microm pore size system, the absorbency at A550 showed no differences between groups. However, in the 3.0 microm pore size system, the absorbency at A550s in the intravitreal gentamicin groups was significantly lower than in the control and the goggle groups (p<0.05), indicating that destruction of the retina-RPE complex inhibited chondrocyte proliferation. The absorbency in the goggle group was higher than in the control group (p<0.05). These results indicate that the retina-RPE complex exerts a positive effect on the proliferation of scleral chondrocytes via a molecule sized between 0.4.and 3.0 microm in diameter.

Embedded hard contact lens: reports of a case.

Contact lens migration into the upper eye lid with resultant lid mass is a rare complication of hard contact lens wear. We present a case in which a cosmetically unacceptable upper lid mass was the chief problem. The patient had switched to soft contact lenses and tolerated them well for about 13 months. From computed tomographic scan pictures and the keratoscopic change, surgical exploration through the opening of a discharging sinus in the upper forniceal area delivered a 8 x 8 mm hard contact lens and a flux of tenacious mucoid discharge. Double eversion of the upper tarsus, which was advised by Green in 1963, was the most important technique in reaching the correct diagnosis, and it should be stressed again on examining patients with a history of displaced hard contact lens.

Evaluation of optic disc changes in severe myopia.

PURPOSE: To evaluate the changes in the optic nerve head in highly myopic subjects by means of confocal laser scanning opthalmoscope. METHODS: Using laser scanning and a three-dimensional image analysis system, we studied 114 young (21.4 +/- 1.4 years), highly myopic subjects with refractive errors greater than -8.0 D and a control group of 29 subjects (18.9 +/- 1.2 years) with myopia of -3.0 D or less. Measurements included cycloplegic refraction, corneal curvature, biometric axial length, and morphometric values of the optic disc obtained with a laser scanning disc analyzer. RESULTS: The optic disc area in highly myopic eyes was similar to that in mildly myopic eyes. However, regression analysis revealed that the optic disc area increased with axial length in subjects with severe myopia. The cup/disc ratio, the disc depth, the neuroretinal rim area, and the tilting of the disc were not significantly different between the severe and mild myopia groups. CONCLUSIONS: These findings may be useful in further investigations of myopic progression and of the mechanisms responsible for the development of myopic complications.

Epidemiologic study of the prevalence and severity of myopia among schoolchildren in Taiwan in 2000.

BACKGROUND AND PURPOSE: A nationwide survey was performed in 2000 to determine the prevalence and severity of myopia among schoolchildren in Taiwan and to compare these findings with the results of the last survey performed in 1995. METHODS: We first divided the whole island into regions according to developmental grade scores and then sampled with the probability proportional to the size of the population within each stratum. A total of 10,889 students were enrolled, including 5,664 boys and 5,225 girls, with ages ranging from 7 to 18 years. The refractive status and corneal radius of each student were measured with an autorefractometer under cycloplegia and checked with retinoscopy. Axial length was measured using biometric ultrasound. RESULTS: The myopia rate increased from 20% at 7 years, to 61% at 12 years, and 81% at 15 years. A myopic rate of 84% was found for schoolchildren aged 16 years through 18 years. The mean refractive index reached myopic status at the age of 8, and increased to -4.12 D in girls and -3.15 D in boys at the age of 18 years. The prevalence of high myopia (> -6.0 D) at the age of 18 years was 24% in girls and 18% in boys. The increase in axial length corresponded with the progression of myopia. The anterior chamber depth was slightly deeper from 7 years to 13 years and then remained stable. The lens thickness decreased from 7 years to 11 years. After age 15, further thickening of the lens was correlated with both age and severity of myopia. However, the corneal curvature was not related to age or severity of myopia. Girls had a higher prevalence and more severe degree of myopia than boys. Children in urban areas had a higher prevalence and more severe degree of myopia than children in rural areas. CONCLUSION: The prevalence and severity of myopia in schoolchildren in Taiwan in 2000 increased compared to 1995, with the most severe increases occurring in younger age groups. Thus, preventing schoolchildren developing myopia at a young age may slow down the increase in severity of myopia in Taiwan.