Irlen syndrome: systematic review and level of evidence analysis / Síndrome de Irlen: revisão sistemática e análise do nível de evidência

ABSTRACT Background: Scotopic sensitivity syndrome, later called Meares-Irlen syndrome or simply Irlen syndrome (IS) has been described as symptoms of poor reading ability due to poor color matching and distorted graphic images. Individuals with this syndrome are considered slow, ineffective readers with low comprehension and visual fatigue. It is still uncertain whether the disease pathophysiology is an independent entity or part of the dyslexia spectrum. Nevertheless, treatments with lenses and colored filters have been proposed to alleviate the effect of the luminous contrast and improve patients' reading performance. However, no evidence of treatment effectiveness has been achieved. Objective: The aim of the present study was to obtain evidence about IS etiology, diagnosis and intervention efficacy. Methods: A systematic review was performed covering the available studies on IS, assessing the available data according to their level of evidence, focusing on diagnostic tools, proposed interventions and related outcomes. Results: The data showed high heterogeneity among studies, and lack of evidence on the existence of IS and treatment effectiveness. Conclusion: The syndrome as described, as well as its treatments, require further strong evidence.

RESUMO Background: A síndrome da sensibilidade escotópica, posteriormente denominada síndrome de Meares-Irlen ou simplesmente síndrome de Irlen (SI), foi descrita como indivíduos com sintomas de baixa capacidade de leitura devido à combinação de cores e distorções nas imagens. Indivíduos com essa síndrome podem apresentar leitura lenta e ineficaz, com baixo nível de compreensão e fadiga visual. A fisiopatologia da doença ainda é incerta como uma entidade independente ou como parte do espectro da dislexia. No entanto, tratamentos com lentes e filtros coloridos foram propostos com o objetivo de aliviar o efeito do contraste luminoso e melhorar o desempenho de leitura dos pacientes. Outrossim, nenhuma evidência de eficácia do tratamento foi alcançada. Objetivos: Obter evidências sobre a etiologia, eficácia diagnóstica e intervenção da SI. Métodos: Foi realizada uma revisão sistemática, cobrindo os estudos disponíveis sobre a SI, avaliando os dados disponíveis de acordo com seu nível de evidência, com foco em ferramentas de diagnóstico, intervenções propostas e desfechos relacionados. Resultados: Os dados mostram alta heterogeneidade, falta de evidência sobre a existência da SI e eficácia do tratamento. Conclusões: A síndrome descrita e seus tratamentos exigem evidências mais robustas.

Clinical outcomes of currently available multifocal intraocular lenses

This study investigates the characteristics and clinical outcomes of different types of extended depth-of-focus and multifocal intraocular lenses (IOLs) to determine which IOL can increase patient satisfaction. Modern cataract surgery has undergone tremendous evolution in terms of IOL quality. Recently, different types of presbyopia-correcting IOLs have become commercially available. Among them, multifocal IOLs are the most frequently used. Multifocal IOLs are different from conventional monofocal IOLs because these have multiple focus, which enable patients to see both distant and near objects at the same time. Multifocal IOLs can be classified as either refractive or diffractive IOLs. Diffractive multifocal IOLs include traditional bifocal lenses and relatively new trifocal lenses, and are the most widely used multifocal IOLs owing to their good clinical performance. Trifocal IOLs have an advantage over bifocal IOLs in terms of intermediate visual acuity, but can cause decreased contrast sensitivity and night vision disturbances. Recently developed extended depth-of-focus IOLs are different from traditional multifocal IOLs in that these extend the focus, resulting in smooth continuous focus. It also has the benefit of better contrast sensitivity and improved visual quality over multifocal IOLs; however, is relatively weak in terms of near visual acuity.

Specific Visual Symptoms and Signs of Meares-Irlen Syndrome in Korean

PURPOSE: To discriminate the visual symptoms and signs of Meares-Irlen syndrome (MIS) and nonspecific dyslexia from other ophthalmologic diseases (NODs). METHODS: Forty-five patients were enrolled. Thirty four of the patients with MIS whose symptoms improved with tinted lenses comprised MIS group. The other 11 patients whose reading difficulty improved with other ocular therapy and did not require tinted lenses comprised NODs group. The main symptoms causing dyslexia and associated ocular diseases were evaluated. RESULTS: The mean age was 17.9 +/- 9.5 years in MIS group, and 19.3 +/- 11.0 years in NODs group. In MIS group, the most common symptoms while reading were difficulty to move lines (85%), doubling (53%), and difficulty in bright condition (27%). On the other hand, blurring was the most common symptom in NODs group (45%). The associated ocular diseases in the two groups were refractive error (79% and 73%), dry eye (29% and 18%), and exophoria (6% and 27%), respectively. CONCLUSIONS: Doubling, difficulty to move lines, and difficulty in bright condition while reading are main specific symptoms in MIS compared to nonspecific dyslexia from other ophthalmologic disorders.

Comparison of Colvardpupillometer, ORBScan II and Sirius in Determining Pupil Size for Refractive Surgery

PURPOSE: To compare pupil size measured by Colvard(R)pupillometer, ORBScan II(R), Sirius(R) and analyze correlation between pupil size and night vision disturbance after refractive surgery according to measuring methods. METHODS: Two hundred eyes of one hundred patients who underwent refractive surgery were retrospectively evaluated. Pupil size was measured with Colvard(R)pupillometer, Sirius(R) in the scotopic light condition and with ORBScan II(R), Sirius(R) in the photopic light condition. Patients filled out questionnaire about night vision disturbance at postoperative three months. Correlation between pupil size according to measuring methods and night vision disturbance was evaluated. RESULTS: The mean age of patient was 26 years and number of male patients was 36. In scotopic light condition, pupil size measured with Colvard(R)pupillometer (6.76 mm) was significantly larger than that of Sirius(R) (6.53 mm) (p < 0.001). In photopic light condition, pupil size measured with ORBScan II(R) (3.98 mm) was significantly smaller than that of Sirius(R) (4.41 mm) (p < 0.001). Night vision disturbance were correlated with pupil size and Sirius(R) in the scotopic light condition had strongest correlation among three measuring method (r = 0.44). CONCLUSIONS: Sirius(R) tends to measure pupil size smaller than Colvard(R)pupillometer in the scotopic light condition. The correlation between night vision disturbance and pupil size was highest in Sirius(R).

Long-Term Quality of Life after Myopic Laser Refractive Surgery

PURPOSE: To investigate long-term satisfaction and quality of life after myopic laser refractive surgery. METHODS: This study included 231 myopic patients who underwent laser refractive surgery (LASIK, LASEK or PRK) at least five years prior, between 2002 and 2005, at 5 hospitals. Using a telephone survey, patients were asked to subjectively answer 26 questions regarding satisfaction, quality of life changes, and visual symptoms. RESULTS: The mean patient satisfaction score was 8.12 (scale of 1 to 10). Improvement in quality of life was reported by 91% of the subjects. Intention to have surgery again was reported by 87.9% of the subjects and intention to recommend refractive surgery to a friend or family was reported by 80.5% of the subjects. The most common discomfort symptoms after myopic laser refractive surgery were dry eye symptoms (57.1%), followed by night vision disturbances (54.3%). CONCLUSIONS: Long-term satisfaction and quality of life were shown to be positive in patients treated with myopic refractive surgery.

Clinical Results and Some Problems of Multifocal Apodized Diffractive Intraocular Lens Implantation

PURPOSE: To evaluate near and far visual outcomes, subjective visual symptoms, and patient satisfaction with AcrySof(R) ReSTOR(R) diffractive multifocal intraocular lenses (IOL), and to study the reasons for postoperative dissatisfaction. METHODS: Twenty-three eyes of 19 patients received phacoemulsifications and implantation of AcrySof(R) ReSTOR(R) IOL. The main outcome measures, taken at postoperative 1 day, 1 week, 1 month, and 3 months, were uncorrected and corrected near and distant visual acuity, refractory errors, subjective visual symptoms (glare, halo, and night vision), and satisfaction. RESULTS: At the 3-month postoperative visit, the mean uncorrected near and distant visual acuities were 0.59+/-0.24 (0.25+/-0.22 LogMAR unit) and 0.78+/-0.27 (0.13+/-0.10 LogMAR unit), respectively. In addition, patients' satisfaction with uncorrected near vision, intermediate vision, far vision, and general visual performance were better than their satisfaction with night vision. Glare and halos were reported as severe by only 10.2% and 5.3% of patients, respectively. The seven eyes with poor patient satisfaction included eyes with a high incidence of preoperative ocular diseases or preoperative and postoperative high corneal astigmatisms of more than 1.0 diopter. CONCLUSIONS: The AcrySof(R) ReSTOR(R) IOL demonstrated good near and distant visual acuity with good patient satisfaction. Previous ocular disease, corneal astigmatism less than 1.0 diopter, and patient lifestyle should be considered to enhance patient satisfaction.

Clinical Outcomes of Wavefront-Guided Epi-LASIK: 6-Months Follow-up

PURPOSE: We evaluate the clinical outcomes after wavefront-guided (WFG) Epi-LASIK in mild and moderate myopia . METHODS: The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, total high order aberrations, contrast sensitivity for day and night vision, and pain score in 114 eyes of 61 patients who had undergone WFG Epi-LASIK were measured preoperatively and at 1 day, 1 week, 1 month, 2 months, and 6 months postoperatively. RESULTS: At 1 day, 1 week, 1 month, 2 months and 6 months postoperatively, UCVA & BCVA had improved significantly. At 1 month postoperatively, the spherical equivalent was -0.93+/-0.74 and showed a stable pattern at 6 months postoperatively. There was no statistically significant difference in total high-order aberration between preoperatively measurements and measurements taken at 6 months postoperative (p=0.745). At a frequency of 19 cpd, night contrast sensitivity showed significant statistical difference (p=0.010) but no difference at low and medium frequencies between preoperative measurements and postoperative six months measurements. Pain subsided at 2 weeks postoperative. All patients maintained clear cornea and suffered no complications. CONCLUSIONS: At 6 months postoperatively, patients who underwent Wavefront-guided Epi-LASIK showed successful results for the correction of moderate myopia and excellent contrast sensitivity at night time. Wavefront-guided Epi-LASIK may solve the visual quality problem after refractive surgery and, therefore, may be clinically useful.

Refractive Surgery 2004 in Korea

PURPOSE: This study investigates both the current situation and future trends in the field of refractive surgery in Korea. METHODS: Members of the Korean Society of Cataract and Refractive Surgery (KSCRS) have been annually surveyed regarding cataract and refractive surgery since 1995. The 2004 annual survey, which consisted of 58 multiple-choice questions, was mailed in May 2004 to 322 KSCRS members; fifty-four (16.8%) members responded. Data from the 2004 survey was compared with that of previous annual surveys and similar studies from the USA. RESULTS: The respondents indicated that patients in their forties accounted for the highest percentage (57%) of subjects, and LASIK accounted for the highest percentage (82%) of refractive surgeries. Degeneration of corrected vision, night halo, and glare accounted for a high proportion of the complications arising after refractive surgery. LASIK was the preferred method for treating myopia less than -12 diopters, while phakic IOL was preferred for myopia more than -12 diopters. Lastly, more respondents indicated that they had experienced legal problems associated with PRK or LASIK than the previous year. CONCLUSIONS: LASIK remains the refractive surgery procedure of choice, although wavefront-guided ablation is gaining in popularity. Approximately half of the respondents indicated they used MMC in their refractive surgeries.

Comparison of the Clinical Results of Lensectomy and LASIK for High Myopia

We retrospectively evaluated clinial results of 13 eyes of 8 patients who underwent lensectomy and 11 eyes of 7 patients who underwent LASIK(laser assisted in sity keratomileusis) for correction of high myopia. Clinical outcomes of uncorrected and corrected visual acuity, postoperative refraction, and contrast sensitivity were evaluated. Subjective tests concerning glare, night halos, or decrement of night vision were also performed in each group. Postoperative uncorrected and corrected visual acuities were not significantly different between two groups. Predicatability was significantly higher in lensectomy group than that of LASIK group. Mean contrast sensitivity value of highest frequency(20 cpd) in LASIK group was significantly lower than that in lensectomy group. Subjective glare or night hlaos occurred more in LASIK group. During follow-up, visual loss with 2 lines or more was noted in 2 eyes due to postoperative complications in lensectomy group. No complication occurred in LASIK group. LASIK has been considered reasonably predictable and safe method for correction of high myopia. But our data suggest that lensectomy may give better quality of vision postoperatively compared to LASIK for high myopia. If prophylactic treatments which are aimed to prevention of postoperative complications are carried out prior to lensectomy, lensectomy is a reasonable refractive surgical potion especially for middle-aged patients with high myopia.

The Comparison between 5.0mm and 6.0mm Ablation Diameter in Surgical Result of Excimer Laser Photorefractive Keratectomy

We analyzed the results of 5.0mm and 6.0mm ablation diameter in excimer laser photorefractive keratectomy using the same excimer laser (Aesculap-Meditec, MEL 60, Germany) In 5.0mm ablation diameter group, forty one eyes of thirty five patients were operated from March 1994 to February 1995 and in 6.0mm ablation diameter group, thirty eyes of twenty three patients were operated from July 1995 to December 1995. All were followed for at least 6 months and analyzed by retrospective method. Refractive change, naked visual acuity, corneal haze and night vision difficulties were measured at 1, 3, and 6 months postoperatively. In eyes treated with 6.0mm ablation diameter, the initial hyperopic shift was reduced with significant differences at 1 and 3 months (p.05). The subjective symptoms of night vision difficulty were significantly lower in the 6.0mm treatment group at 1 and 3 months (p=0. 0067, p=0.02). In conclusion, treatment with 6.0mm ablation diameter made less initial hyperopic shift and reduction of side effects in comparison with 5.0mm ablation diameter.

A Comparison of Contrast Sensitivity Between Strabismic and Anisometropic Amblyopia

Contrast sensitivity was measured by MCT 8000(R)(Vistech Consultant INC, U.S.A.) in two groups: 23 strabismic amblyopes and 10 anisometropic amblyopes. In general, the amblyopic eyes exhibited a statistically significant loss of contrast sensitivty in both day and night vision. When visual acuity was equated between groups, the anisometropic group had a greater loss of contrast sensitivity at the high spatiaI frequencies and the strabismic group exchibited a similar loss of contrast at all spatial frequencies. Test-retest correlations(average 0.76) were statistically significant, which demonstrated that the test using MCT 8000(R) was reliable.

The Aasesament of Contrast Sensitivity by MCT 8000(R) in Normal Eyes and Peeudophakic Eyes

The standard vision test using Snellen acuity is not always an accurate indicat or of functional vision loss. Acuity measures optical blur, but psudophakic eyes frequently do not affect optical blur. Therefore, acuity cannot provide relevant informations on the loss of vision experienced by the patients. Contrast sensitivity, not acuity, has been shown to be effective in determining functional vision loss due to psudophakic eyes. The MCT 8000(R), glare and contrast sensitivity system. was used for measurement of contrast sensitivity in 19 pseudophakic eyes at postoperative 1 month, 18 pseudophakic eyes at post-operative 3 months and 18 normal control eyes. The results were as follows: 1) Contrast sensitivity decreased in pseudophakic eyes compared to normal eyes in four different conditions; day vision, day vision with perpheral glare, night vision and night vision with central glare. 2) In pseudophakic eyes, contrast sensitivity was not different between 1 month and 3 months postoperatively.