Cystoid macular oedema and changes in retinal thickness after phacoemulsification with optical coherence tomography

AIMS

To study the incidence of cystoid macular oedema and changes in retinal thickness after phacoemulsification with optical coherence tomography (OCT).

METHODS

In all, 131 eyes of 131 patients were studied at the ophthalmology clinic at Tung Wah Eastern Hospital from September 2001 to October 2002. All the patients had clinical assessment and OCT preoperatively and at weeks 2, 4, and 8 postoperatively. The incidence of postoperative cystoid macular oedema (CMO) was evaluated. The foveal thickness (FT) and central 1 mm retinal thickness (CT) at different time intervals were analysed.

RESULTS

Four (3.05%) patients developed CMO after phacoemulsification, which was evident clinically and tomographically. Fluorescein angiogram confirmed leakage in all cases. For other patients, the mean preoperative FT was 189.36 +/- 26.83 microm. The mean FT, were 175.74 +/- 26.79 microm, 180.25 +/- 27.13 microm, 176.58 +/- 26.45 microm at 2 weeks, 4 weeks, and 8 weeks postoperatively, respectively. The preoperative FT was significantly thicker than those in the postoperative period. The same trend was noted for CT.

CONCLUSION

OCT is useful for detecting and confirming clinical CMO after cataract surgery; however, its use in detecting subtle changes in retinal thickness is limited by the normal variation in retinal thickness. The measurement of retinal thickness with OCT may also be affected by the status of the lens.

Intravitreal injection of bevacizumab for choroidal neovascularisation associated with pathological myopia

AIM

To assess the efficacy and safety of an intravitreal injection of bevacizumab (Avastin(R)) for myopic choroidal neovascularisation (mCNV).

METHODS

Intravitreal bevacizumab (1 mg) was injected into eight eyes of eight patients with mCNV in this non-randomised, interventional case series. The best-corrected visual acuity (BCVA) was measured and the optical coherence tomography (OCT) and fluorescein angiography findings were examined before and after treatment. The minimum follow-up time was 3 months.

RESULTS

The mean BCVA was 0.26 before treatment and 0.51 at the last visit (p = 0.009). The BCVA improved to two or more lines in six eyes (75%) and remained the same in two eyes (25%). Leakage from the mCNV on fluorescein angiography decreased in seven eyes (87.5%). The choroidal neovascularisation area on fluorescein angiography (p = 0.049) and the foveal thickness on OCT images decreased significantly (p = 0.027) after the treatment. No major complications developed.

CONCLUSION

Intravitreal injection of bevacizumab seems to be an effective and safe treatment for mCNV.

Intravitreal tissue plasminogen activator to treat macular edema associated with branch retinal vein occlusion

PURPOSE

To evaluate the efficacy of intravitreal tissue plasminogen activator (tPA) injection for branch retinal vein occlusion (BRVO).

DESIGN

Retrospective, interventional case series.

METHODS

Seventeen eyes presenting with macular edema caused by BRVO were treated with an intravitreal tPA (Monteplase, 40 k IU) injection. We assessed the visual acuity (VA) and foveal thickness measured with optical coherence tomography.

RESULTS

The mean duration of symptoms before surgery was 3.6 +/- 3.8 weeks. The mean logMAR VA significantly improved from 0.603 +/- 0.327 at baseline to 0.388 +/- 0.248 (P < .01) at one month and 0.359 +/- 0.319 (P < .05) at six months. The mean foveal thickness significantly decreased from 738 +/- 156 microm at baseline to 454 +/- 213 microm (P < .001) at one month and 253 +/- 164 microm (P < .001) six months.

CONCLUSION

Intravitreal tPA injection may be an effective treatment for resolving macular edema and improving the VA in BRVO.

Indocyanine green angiographic features of myopic subfoveal choroidal neovascularization as a prognostic factor after photodynamic therapy

Purpose

To determine the influence of clinical features and Indocyanine green (ICG) angiographic features on the visual outcome of patients with myopic sub-foveal choroidal neovascularization (CNV) who received photodynamic therapy (PDT).

Methods

Thirty-six consecutive patients (39 eyes) with myopic CNV who were followed up for more than one year after PDT were enrolled in this study. Clinical features included age, gender, refractive error, great linear dimension, and subretinal hemorrhage. ICG features included the lesion size, lacquer cracks, hypofluorescence surrounding the CNV (dark rim), peripapillary atrophy size, and visible prominent choroidal veins under the macula. Linear regression analysis was performed using the change in visual acuity (ΔlogMAR) as the dependent variable and the above factors as independent variables.

Results

At one-year follow-up after PDT, a younger age (p=0.002) and the presence of a dark rim (p=0.002) were significantly correlated with an improvement of visual acuity (decrement in logMAR) after PDT. Other factors had no significant influence on changes in visual acuity.

Conclusions

Younger patients and patients with a dark rim on ICG angiography had a higher chance of visual improvement after PDT in myopic CNV.

Development of the human retina in the absence of ganglion cells

Retinal development was studied in eyes from fetal and neonatal human anencephalic (AnC) and normal age-matched infants to determine the time of retinal ganglion cell (GC) loss and its effect on the development of other retinal neurons. At fetal week (Fwk) 14, GC loss was evident in central retina and by Fwk 19-20 almost all GC were absent, although immunocytochemical labeling for GC markers brain 3, neurofilament M and parvalbumin detected a few GC in the AnC far periphery at older ages. The inner nuclear and inner plexiform (IPL) layers showed variable amounts of thinning but all normal bipolar (BP) and horizontal cell markers were still present. The amacrine (AM) labels calbindin and calretinin were markedly reduced. Lamination for these markers in the IPL was less organized than in normal retinas, with BP and AM markers extending into the degenerated GC layer. Cone and rod photoreceptors had normal morphology and topography in AnC retina and each expressed normal phototransduction and synaptic markers. The prospective fovea was identified in AnC neonatal retina by cone packing and the absence of immunolabeled rod photoreceptors. In one AnC neonatal retina, blood vessels and astrocytes extended across the inner retina in the putative fovea and there was no evidence of a pit. In another AnC neonatal retina, blood vessels and astrocytes formed a foveal avascular zone in the inner retina and a shallow pit was present within this zone. However, both foveas showed evidence for the onset of cone elongation and packing. These findings support the model of Springer and Hendrickson [2005; Vis. Neurosci. 22, 171] in which the foveal avascular zone is critical for pit formation, but suggest that mechanisms inherent to the outer retina may be involved in early stages of foveal cone packing.

Change of foveal and perifoveal thickness measured by OCT after phacoemulsification and IOL implantation

PURPOSE

Cataract surgery is known to elicit postoperative macular oedema owing to its traumatic effect. The aim of the study was to measure the foveal and perifoveal thickness of the retina after uneventful phacoemulsification and posterior chamber intraocular lens (PC-IOL) implantation.

METHODS

Retinal thickness values of the foveal and perifoveal (fovea+3.0 mm, fovea+6.0 mm) sectors and the minimum values were measured in a prospective study using optical coherence tomography (OCT) in 71 eyes of 71 patients (34 men, 37 women, mean age: 68.8 years) who underwent cataract surgery. Phacoemulsification and 'in the bag' implantation of a foldable PC-IOL was performed under topical anaesthesia. Data were collected 1 day before the operation, and postoperatively at 1, 7, 30, and 60 days. Contralateral eyes of each patient served as controls. 'Student's t-test' was used for statistical analysis, and P<0.05 value was considered significant.

RESULTS

No significant change of the thickness values could be measured 1 day after surgery. However, a significant increase could be detected on the postoperative 7, 30, and 60 days in the perifoveal 3.0 and 6.0 mm sectors either calculated alone or averaged together with the foveal values. The initial (preoperative) average value of 234.1+/-2.6 microm (mean+/-SEM, n=536) in the 6.0 mm perifoveal region increased to 242.5+/-2.6 microm (mean+/-SEM, n=488, P<0.01) 1 week, to 247.7+/-4.6 microm (n=352, P<0.01) 1 month, and to 246.0+/-5.9 microm (n=208, P<0.05) 2 months after surgery, which proved to be significant. However, the relative change of macular thickness was moderate, 3.5, 5.6, and 5.3% at the above periods, respectively. In a subgroup of patients (n=34) minimum 6 months after cataract surgery, the 6.0 mm perifoveal values were found to be elevated at (237.8+/-3.9 microm, mean+/-SEM, n=272) as compared to the control eyes (233.9+/-3.8 microm, mean+/-SEM, n=272). The difference was 1.7% and proved not to be significant (P>0.05).

CONCLUSIONS

Mild subclinical perifoveal oedema following cataract surgery was detected using OCT at postoperative day 7 to 6 months. The minimal and the foveal values in itself are inadequate to describe the phenomenon. The macular thickness values of the perifoveal 3.0 and 6.0 mm sectors alone or averaged together with the foveal values provide more accurate description of the postoperative macular oedema.OCT enables the detection of minimal increases in perifoveal retinal thickness even 6 months after cataract surgery.

Spectrum of foveal development in albinism detected with optical coherence tomography

BACKGROUND

Optical coherence tomography (OCT) has shown the absence of a foveal depression in an individual with oculocutaneous albinism, type 1 (OCA1) and best-corrected visual acuity (BCVA) of 20/400. However, the presence of an annular light reflex in the macula has been noted with indirect ophthalmoscopy in other patients with albinism who have better vision. We studied macular architecture in albinism with OCT when binocular BCVA was > or = 20/60 and compared this to detection of foveal development with binocular indirect ophthalmoscopy.

METHODS

Eleven patients with albinism and BCVA > or = 20/60 were recruited for OCT. Average central macular thickness was recorded. Presence of an oval annular reflex was determined with binocular indirect ophthalmoscopy.

RESULTS

Mean binocular BCVA was 20/39 (range: 20/20 to 20/50). Twelve eyes had a rudimentary annular reflex detected with ophthalmoscopy. OCT was reliable in 20 of 22 eyes. A foveal depression was identified with OCT in four eyes. Mean macular thickness for these four eyes was 233 microm (+/- 22.5 microm). We found a weak inverse correlation between BCVA (logMAR) and thickness (r = -0.21).

CONCLUSIONS

OCT shows the spectrum of foveal development in albinism, from complete absence of development to a central depression corresponding to a rudimentary annular reflex detected with ophthalmoscopy. The reduced rate of detection of foveal development with OCT compared with ophthalmoscopy is likely related to poor fixation in patients with nystagmus.

The transient efficacy of a single intravitreal triamcinolone acetonide injection for diabetic macular edema

BACKGROUND

The major cause of visual impairment in diabetic patients is macular edema. The failure of laser photocoagulation in a large subgroup of patients with clinically significant diabetic macular edema has prompted interest in other treatment methods.

OBJECTIVES

To evaluate the long-term efficacy and safety of an intravitreal injection of triamcinolone acetonide for clinically significant diabetic macular edema.

METHODS

In a retrospective case series 31 diabetic patients with persistent, recurrent or diffuse clinically significant diabetic macular edema received a single 4 mg (0.1 ml) intravitreal triamcinolone acetonide injection and were followed for at least 6 months. The main outcome measures evaluated were classified as primary: visual acuity and central macular thickness, and secondary: intraocular pressure and cataract progression. Statistical analysis included Student's t-test, chi-square test and the MacNamar test.

RESULTS

Best visual acuity results were observed 2.6 +/- 2.4 months post-injection. At that time the mean foveal thickness had decreased by 37% from a baseline of 455 +/- 100 to 288 +/- 99 mu (P< 0.001) and the mean visual acuity improved from 6/42 to 6/23 (P< 0.001). Final mean visual acuity after an average of 10 +/- 1.8 months follow-up (range 6-13 months) was identical to the baseline, although mean foveal thickness was still significantly lower than the initial thickness (368 +/- 166 vs. 455 +/- 100 mu, P< 0.01). Statistical analysis did not identify any pre-injection prognostic factors for improved visual acuity. The only complications that occurred were elevated intraocular pressure in 42% of patients and cataract progression in 21%. There was no endophthalmitis.

CONCLUSIONS

Intravitreal injection of triamcinolone acetonide for clinically significant diabetic macular edema is effective in reducing foveal thickness and improving visual acuity in the short term. Longer follow-up revealed that visual acuity returned to pre-injection values, even though a modest decrease in the foveal thickness persisted. Further studies are needed to evaluate the long-term efficacy in conjunction with laser photocoagulation treatment.

Adult-onset foveomacular vitelliform dystrophy

BACKGROUND

Adult-onset foveomacular vitelliform dystrophy (AOFVD) is a condition that presents classically as bilateral, symmetrical, grayish-yellow, round or oval-shaped lesions within the macular area. These lesions are mildly elevated and are typically one third to one half disc diameter in size. The onset of the disease is usually between 30 and 50 years of age with variable genetic inheritance, although some have suggested an autosomal dominance inheritance pattern. Patients with AOFVD typically present with symptoms of blurred vision or mild metamorphopsia. Results of diagnostic testing show a normal or mildly subnormal electro-oculogram (EOG). Fluorescein angiography results (FA) typically show hypofluorescence in the area corresponding to the vitelliform lesion and a surrounding ring of hyperfluorescence. Results of optical coherence tomography (OCT) show the vitelliform lesion as being located in the retinal pigment epithelium (RPE) layer or between the RPE and photoreceptor layer.

CASE REPORTS

Two cases of AOFVD are presented with each patient having different macular appearances owing to the different stage of the disease process. In case 1, a 76-year-old white man presented with stage II AOFVD characterized by typical vitelliform lesions. His best-corrected acuities were 20/70+ in the right eye (O.D.) and 20/80- in the left eye (O.S.). In case 2, a 54-year-old white man presented with stage V AOFVD with bilateral atrophic maculae with best-corrected acuities of 10/60- O.D. and 10/160- O.S.

CONCLUSION

Patients with adult-onset foveomacular vitelliform dystrophy typically have slow progressive vision loss. However, patients can develop dramatically decreased vision owing to subfoveal choroidal neovascularization (CNV). Thus, it is important to establish the correct diagnosis and monitor this condition. Furthermore, because there are reports of AOFVD having an autosomal dominance inheritance pattern with variable penetrance, it is recommended that the patient's family members have a comprehensive eye examination to rule out any early signs of this rare eye condition.

Ocular coherence tomographic examination of postoperative foveal architecture after scleral buckling vs vitrectomy for macular off retinal detachment

AIMS

This pilot study uses Optical Coherence Tomography (OCT) imaging to compare the difference in foveal architecture after successful retinal detachment (RD) surgery by scleral buckling or pars plana vitrectomy (PPV).

METHODS

Prospective recruitment of patients with macular off RDs. Detachment surgery was undertaken by scleral buckling, external drainage, and air injection (group 1) or by PPV (group 2). Postoperatively patients had clinical examinations and OCT at 1, 3, 6, and 12 months. If abnormalities persisted, a further OCT was obtained at 18 months.

RESULTS

Retinal reattachment, including clinical macular reattachment, was achieved in all cases within 24 h postoperatively. In group 1 (n=22), postoperative OCT showed persistent foveal detachment in 63% of cases (n=14) at 1 and 3 months. At 6 and 12 months, 36% (n=8) and 9% (n=2) had a persistent foveal detachment, respectively, and at 18 months, foveal detachment eventually. In group 2 (n=21), postoperative OCT showed an attached fovea in all cases; however, foveal thickening suggesting intraretinal oedema was present in all cases. The oedematous appearance of retina on OCT settled in 1-3 months. No foveal abnormality was seen at 6 and 12 months postoperatively.

CONCLUSIONS

A high proportion of patients with successful retinal reattachment surgery by scleral buckling had foveal detachments postoperatively. No cases who had PPV had foveal detachments; however, transient retinal oedema was evident in all cases. The aetiology of these changes is unknown and warrants further investigation, as there is the potential of a long-term effect on vision.

Decreasing efficacy of repeated intravitreal triamcinolone injections in diabetic macular oedema

BACKGROUND/AIM

Intravitreal triamcinolone (IVTA) results in transient improvements in diabetic macular oedema (DMO), necessitating repeated injections. The authors report a case series of 10 eyes of 10 patients with DMO, who received a repeat injection of 4 mg IVTA, at least 26 weeks after the first injection of the same dose.

METHOD

Pre-injection and at 2, 4, 9, and 17 weeks post-injection, best corrected visual acuity (BCVA) and central foveal thickness (CFT) on optical coherence tomography, after the first and repeat injections, were compared using paired t test. Side effects were monitored.

RESULTS

BCVA, CFT, intraocular pressure (IOP), and cataract scores were not significantly different before initial and repeat injections (given at 32.5 (SD 3.5) weeks after the first injection). Transient improvements of BCVA and CFT were achieved after both injections. However, after the repeat injection, the BCVA was significantly worse at all time points (p<0.05) and so were the best achieved CFT and the CFT at 4 weeks post-injection (p = 0.034 and 0.011 respectively), compared with the initial injection. Post-injection maximum IOPs and increase in cataract scores were not significantly different between the two injections.

CONCLUSION

A repeat injection of 4 mg of IVTA may not be as effective as an initial injection for the treatment of DMO.

Optical coherence tomography of idiopathic juxtafoveolar telangiectasia

BACKGROUND AND OBJECTIVE

To document optical coherence tomography (OCT) findings in a series of eyes with group 2A idiopathic juxtafoveal telangiectasia.

PATIENTS AND METHODS

This study is a retrospective review of patient charts, OCT, fundus photography, and fluorescein angiography involving 23 eyes (12 patients). Mean retinal thickness in 9 macular areas was calculated and compared to previously published measurements from normal eyes.

RESULTS

OCT in 8 of 13 stage 3 eyes revealed foveal cysts without evidence of cystoid macular edema on fluorescein angiography or biomicroscopy, and 1 lamellar hole. In stage 3 eyes, mild retinal thickening was found in 7 of 9 macular areas (P < .05).

CONCLUSIONS

OCT commonly reveals foveal cysts in stage 3 idiopathic juxtafoveal telangiectasia. Consistent findings of associated mild macular thickening and lack of late petaloid hyperfluorescence on fluorescein angiography suggest that these cysts differ in pathophysiology from cystoid macular

Posterior sub-Tenon's capsule injection of triamcinolone acetonide prevents panretinal photocoagulation-induced visual dysfunction in patients with severe diabetic retinopathy and good vision

PURPOSE

To evaluate prospectively the efficacy of a single sub-Tenon's capsule injection of triamcinolone acetonide (TA) against panretinal photocoagulation (PRP)-induced macular thickening and visual disturbance in patients with severe diabetic retinopathy and good vision.

DESIGN

Prospective, comparative, interventional case series.

PARTICIPANTS

Twenty eyes of 10 patients with severe nonproliferative diabetic retinopathy or non-high-risk proliferative diabetic retinopathy whose visual acuity was 20/40 or better (<0.3 in logarithm of the minimum angle of resolution [logMAR] acuity) before the PRP, whose retinopathy was bilateral and symmetrical. The averaged parafoveal retinal thickness was more than 300 microm, leading to a worse visual prognosis after PRP.

INTERVENTION

Sub-Tenon's capsule injection of 20 mg TA.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA) with logMAR chart and averaged foveal thickness (FT) using the retinal mapping program of optical coherence tomography.

METHODS

In all patients, PRP was performed every other week for 4 sessions on both eyes, and 1 week before PRP; 1 eye received the TA injection, and the other eye served as a control. The clinical course of BCVA and FT was monitored for up to 24 weeks after beginning PRP.

RESULTS

Before TA injection, BCVA and FT were 0.055+/-0.072 and 235.5+/-37.5 microm in the TA-injected eye and 0.065+/-0.071 and 233.7+/-39.8 microm in the control eye, respectively; there was no significant difference between eyes. After the TA injection, FT in the TA-injected eyes was significantly decreased. During and after the PRP, FT in the control eye increased dramatically and reached 312.0+/-68.2 microm at 24 weeks, which was significantly different from that in the TA-injected eyes (235.3+/-38.6 microm at 24 weeks). Best-corrected visual acuity in the control eye decreased with time to 0.24+/-0.13; in contrast, and BCVA in the TA-injected eye was good (to 0.085+/-0.11) .

CONCLUSIONS

As a pretreatment for PRP, a single sub-Tenon's capsule injection of TA has beneficial effects for preventing PRP-induced foveal thickening and visual dysfunction in patients with severe diabetic retinopathy and good vision.

Intravitreal Triamcinolone Acetonide for Persisting Cystoid Macular Edema After Penetrating Keratoplasty

PURPOSE

The intravitreal application of triamcinolone acetonide as treatment of long-standing, therapy-resistant cystoid macular edema after penetrating keratoplasty is reported.

METHODS

A 44-year-old patient showed therapy-resistant cystoid macular edema for 2 years after repeated penetrating keratoplasty was performed as treatment of keratoconus. The crystalline lens was clear. The patient received an intravitreal injection of approximately 20 mg of triamcinolone acetonide. Preinjection visual acuity measured 20/80.

RESULTS

Within the first 4 weeks after the injection, dense cataract developed necessitating cataract surgery. After phakoemulsification, visual acuity improved to 20/50. Optical coherent tomography and fluorescein angiography showed an almost complete resolution of cystoid macular edema. Ten months after the injection, visual acuity remained at 20/50, and intraocular pressure measured 15 mm Hg without antiglaucomatous therapy taken.

CONCLUSIONS

Intravitreal injection of triamcinolone acetonide may be an additional tool in the treatment of therapy-resistant cystoid macular edema after penetrating keratoplasty. After intravitreal injection of triamcinolone acetonide, cataract may rapidly develop in eyes that have been intensively treated, topically and systemically, by corticosteroids for several years.

Nutritional manipulation of primate retinas. IV. Effects of n--3 fatty acids, lutein, and zeaxanthin on S-cones and rods in the foveal region

Lutein and zeaxanthin are xanthophylls selectively accumulated by primate retinas that may protect the macula from age-related macular degeneration. In this project, we manipulated n-3 fatty acids, lutein and/or zeaxanthin levels in the diet and studied their possible outcome on S-cone and rod cell density in the foveal region. Rhesus monkeys (7-16 year, n=17) were fed from birth xanthophyll-free semipurified diets with either adequate or low n-3 fatty acids. Five monkeys were supplemented with lutein and six with zeaxanthin for 6-24 months, while six remained xanthophyll-free until sacrifice. Retinas were embedded in methacrylate and serial 2 microm sections were cut along the vertical meridian. Rod nuclei, and immuno-labelled outer segments of S-cones and rods, were reconstructed and counted in an 8 microm strip. The density profiles were compared with data from control monkeys (n=7) fed a standard laboratory diet. S-cone density profiles were symmetrical along the vertical meridian and the densities decreased rapidly with retinal eccentricity. Rod densities were higher in the superior region than the inferior region in most of the control and experimental animals. Unlike the significant effects observed for retinal pigment epithelial cells of these same monkeys (Leung, I.Y-F., Sandstrom, M.M., Zucker, C.L., Neuringer, M., Snodderly, D.M., 2004. Nutritional manipulation of primate retinas. II. Effects of age, n-3 fatty acids, lutein, and zeaxanthin on retinal pigment epithelium. Invest. Ophthalmol. Vis. Sci. 45, 3244-3256), neither xanthophyll supplementation nor low dietary n-3 fatty acids produced consistent effects on S-cone or rod density profiles of the experimental animals. However, monkeys low in n-3 fatty acids had increased variability of S-cone density in the fovea and low density of foveal rod outer segments. The high variability suggests that the photoreceptors of some animals were resistant to the nutritional manipulations, while others may have been affected. Thus, the photoreceptors appear less sensitive than the retinal pigment epithelium to these nutritional manipulations. However, it is possible that more consistent effects would emerge at a later age or after exposure to stressors such as high light levels.

Correlation of clinical and genetic findings in Hungarian patients with Stargardt disease

PURPOSE

Autosomal recessive Stargardt disease (arSTGD) presents with substantial clinical and genetic heterogeneity. This study was conducted to correlate foveolar thickness (FT) and total macular volume (TMV), measured by optical coherence tomography (OCT), with other clinical characteristics and with specific genetic variation in Hungarian patients with arSTGD.

METHODS

After a standard ophthalmic workup, both eyes of 35 patients with STGD from Hungary and of 25 age-matched healthy control subjects were tested with OCT. FT and TMV were measured automatically with the OCT mapping software in the nine Early Treatment Diabetic Retinopathy Study areas of 3500 microm in diameter. All patients were screened for mutations by a combination of the ABCR400 microarray and direct sequencing.

RESULTS

The patients with STGD presented with markedly thinned retina in the foveola and decreased macular volume, 72 microm and 1.69 mm3, respectively, compared with 169 microm and 2.48 mm3 in the normal subjects, respectively. Statistically significant correlation was observed between visual acuity (VA) and TMV and between VA and FT. Disease-associated mutations were detected in 23 (65.7%) of 35 patients, including 48.5% with both alleles and 17.2% with one allele. The most frequent ABCA4 alleles in Hungarian patients with STGD were L541P/A1038V (in 28% of all patients), G1961E (20%) and IVS40+5G-->A (17%). Specific genotypes correlated with some phenotypic features and allowed for predictions of the disease progression.

CONCLUSIONS

Hungarian patients with STGD presented with extensive foveolar thinning and macular volume loss. Genetic analysis detected several ABCA4 alleles at high frequency in the cohort of patients, suggesting founder effect(s). Unusually homogeneous distribution of disease-associated mutations aided genotype-phenotype correlation analyses in this population.