Evaluation of fixation characteristics in amblyopia using microperimetry.

PURPOSE: To evaluate fixation characteristics in amblyopia using macular analyzer integrity assessment (MAIA) microperimetry and to investigate the factors affecting fixation stability. METHODS: This prospective, cross-sectional study enrolled a total of 58 amblyopic patients who were between 8 and 55 years old. Average threshold macular sensitivity (AT) and fixation characteristics were assessed using MAIA microperimetry. Two Bivariate contour ellipse area (BCEA) fixation indices (63% and 95% proportional values) and the percentage of fixation points within 1° and 2° from the fovea (P1 and P2) were used to assess fixation stability. Non-amblyopic fellow eyes were used as the control group for comparison. RESULTS: AT and fixation stability indices (P1, P2, BCEA 63%, BCEA 95%) were worse in the amblyopic eyes than in the fellow eyes (p < 0.05, for all indices). There was a moderate positive correlation between best corrected visual acuity (BCVA), and AT, and P2, and a moderate negative correlation between BCVA, and BCEA indices. 48% of the eyes were eccentrically fixating (the percentage was 25% in the anisometropic group, 52% in the strabismic group, and 69% in the combined group) and 32% in the non-amblyopic eye (p = 0.052). The preferred fixation eccentricity in amblyopic eyes was significantly greater than the non-amblyopic eyes (p = 0.004), and there was a negative correlation between preferred fixation eccentricity and BCVA (p = 0.012, r = - 0.327). CONCLUSIONS: Our data showed a decrease in fixation stability, a positive correlation between fixation stability and BCVA, and a negative correlation between preferred fixation eccentricity and BCVA in amblyopic eyes.

Evaluation of Behavioral Characteristics in Response to Visual Stimuli in Infants with Cerebral Visual Impairment.

Objectives: To evaluate the behavioral characteristics of infants with cerebral visual impairment (CVI) in response to visual stimuli and the frequency of these features. Materials and Methods: In this retrospective study, 32 infants aged 8-37 months who were referred to the low vision unit in 2019-2021 and diagnosed with CVI based on their demographic characteristics, systemic findings, and standard and functional visual examinations were evaluated. The frequency of ten behavioral characteristics exhibited by infants with CVI in response to visual stimuli as defined by Roman-Lantzy was examined in the patients. Results: The mean age was 23.46±11.45 months, the mean birth weight was 2,550±944 g, and the mean gestational age at birth was 35.39±4.68 weeks. There was hypoxic-ischemic encephalopathy in 22%, prematurity in 59%, periventricular leukomalacia in 16%, cerebral palsy in 25%, epilepsy in 50%, and strabismus in 68.7% of the patients. Color preference for fixation was observed in 40% and visual field preference was observed in 46% of the patients. The most preferred color was red (69%) and the most preferred visual field was right visual field (47%). Difficulty with distance viewing was observed in 84% of patients, visual latency in 72%, need for movement in 69%, absence of visually guided reach in 69%, difficulty with visual complexity in 66%, difficulty with visual novelty in 50%, light-gazing/nonpurposeful gaze in 50%, and atypical visual reflexes in 47%. There was no fixation in 25% of the patients. Conclusion: Behavioral characteristics in response to visual stimuli were observed in most infants with CVI. Knowing and recognizing these characteristic features by ophthalmologists will assist in early diagnosis, referral to visual habilitation, and planning habilitation techniques. These characteristic features are important in order to not miss this critical period in which the brain is still plastic and good responses to visual habilitation can be obtained.

Comparison of Reading Test Parameters from the Print and Tablet Application Forms of the Minnesota Low Vision Reading Test.

Objectives: To compare reading parameters measured with the Turkish version of the Minnesota Low Vision Reading Test (MNREAD-TR) printed acuity chart and the tablet application version of the same test for both normally sighted and low-vision individuals. Materials and Methods: A total of 116 individuals (92 normally sighted and 24 low-vision) were included in the study. All participants were tested with both the print version of the MNREAD-TR chart (method 1) and the tablet application version (method 2). Reading acuity (RA), critical print size (CPS), maximum reading speed (MRS), and reading accessibility index (ACC) were compared statistically. Results: No statistically significant difference was found in RA and CPS between the two methods for the normally sighted individuals (p=0.083 and p=0.075, respectively). There was no statistically significant difference in RA and ACC between the two methods for the patients with low vision (p=0.159 and p=0.103, respectively). The mean MRS was 233.1±34.7 words per minute (wpm) with method 1 and 169.3±23.4 wpm with method 2 in the normally sighted group (p<0.001) and 93.2±50.2 wpm with method 1 and 68.2±34.7 wpm with method 2 in the low-vision group (p<0.001). Conclusion: In our study, it was found that the parameters RA and CPS in the normally sighted individuals and RA and ACC in the low vision individuals provided similar results in both forms of the MNREAD. The tablet application method can be preferred to eliminate evaluators' bias of scoring the printed chart. In addition, applications have other advantages such as being faster and more practical and providing automatic analysis of parameters, especially in low-vision rehabilitation.

Comparison of Two Different Contrast Sensitivity Testing Methods in Patients with Low Vision.

Purpose: To assess the agreement between two different contrast testing modalities using the index of contrast sensitivity (ICS) in patients with low vision. Methods: Thirty-eight patients with low vision were included in the study. Contrast sensitivity (CS) was measured binocularly with both the Vector vision-standardized CS test (CSV-1000E, Vector Vision Co, Greenville, Ohio, USA) and the MonPack 3 (Metrovision, France) after refractive correction for each participant. Based on the data from the two tests, the ICS was calculated. The Bland-Altman technique was used to evaluate the agreement between ICSs obtained from different test methods. Results: Range of best corrected visual acuity was 0.50-1.00 logMAR. According to the median logCS values, CS values were highest at 3 cycles per degree (cpd) for the CSV-1000E test and at 1.5 cpd for the Metrovision MonPack 3 test. The median ICS for CSV-1000E was -0.22 (95th percentile 4.75), and the median ICS for Metrovision MonPack 3 was 0.08 (95th percentile 1.65). The mean difference was 0.655 (between -3.82 and 5.13) within limits of agreement (LoA). The difference and mean values between the two CS test measurements were found to be within LoA range. Conclusions: An agreement was found between the Metrovision MonPack 3 test and the standard CSV-1000E test results in patients with visual impairment. However, the agreement range was within very wide limits. Therefore, it was thought that they may not be used interchangeability in clinical practice.

Fixation Stability and Preferred Retinal Locus in Advanced Age-Related Macular Degeneration

Objectives: To evaluate fixation stability and characteristics of the preferred retinal locus (PRL) in patients with advanced age-related macular degeneration (AMD). Materials and Methods: Sixty-three eyes of 63 patients with AMD who presented to the low vision unit were included in this prospective study. Sociodemographic characteristics, eye examination findings, and reading performance results with the Minnesota Low Vision Reading test were evaluated. Microperimetry was used to evaluate fixation stability and PRL characteristics. Results: There was unstable fixation in 68% of the eyes, relative stable fixation in 27%, and stable fixation in 5%. The mean PRL-foveal distance was 5.15°±3.31° (range 0.75°-14.2°). PRL-foveal distance was greater in cases with unstable fixation than cases with stable fixation (p=0.023). Distance of the PRL from the lesion margin was not associated with absolute scotoma size or fixation stability (p=0.315, p=0.095, respectively). PRLs were most frequently located in the nasal quadrant (31%), followed by the superior quadrant (26%) of the retina. There was no significant relationship between PRL location and fixation stability (p=0.088). Fixation stability was significantly associated with reading speed (p=0.003). Conclusion: In advanced AMD, PRL-foveal distance is an important factor in fixation stability. Knowing the factors that affect fixation stability may be important in determining low vision rehabilitation strategies for these patients because of the strong association between fixation stability and reading speed.

The Effectiveness of Corneal Epithelial Debridement Performed with an Alcohol-Impregnated Sponge.

OBJECTIVE: To evaluate the clinical outcomes of patients who underwent corneal surgery with debridement of epithelium by localised application of an alcohol-impregnated sponge instead of the usual alcohol reservoir method. DESIGN: This study retrospectively included 52 eyes of 27 patients who underwent LASEK (laser-assisted subepithelial keratectomy) and CXL (cross-linking) surgery after application of this alcohol-assisted debridement method between January 2019 and April 2019. PARTICIPANTS: Twenty-four patients who underwent LASEK and three patients who underwent CXL surgery were included in this study, which comprised a total of 52 eye operations. METHODS: Epithelial debridement was performed after placing a 20% ethanol-impregnated sponge on the cornea for 20 seconds. RESULTS: The mean pachymetry value was 509.40 ± 30.37 µm, the mean preoperative spherical equivalent was - 2.14 ± 1.02 dioptres, and the highest myopia and astigmatism values were - 4.25 dioptres and - 2.75 dioptres, respectively. It was seen that the corneal epithelium was completely and easily debrided in a size identical to that of the applied sponge. CONCLUSIONS: Complete debridement of the corneal epithelium can be performed quickly, safely, and easily with this specially prepared sponge.

Evaluation of vision-related quality of life in retinitis pigmentosa patients with low vision.

PURPOSE: To investigate the effect of sociodemographic and clinical characteristics on vision-related quality of life (QoL) in retinitis pigmentosa (RP) patients with low vision. STUDY DESIGN: Retrospective. PATIENTS AND METHODS: Thirty-three RP patients with low vision who had tunnel vision due to RP and 27 volunteers with healthy vision (controls) were included in the study. Visual loss was classified according to the International Classification of Diseases (ICD-10). The National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) was used to determine vision-related QoL. Static automated perimetry (Central 30-2 threshold program) was used for visual field testing, and the degree of the central visual field was calculated. Reading speed was calculated using the Minnesota Low-Vision Reading Acuity Chart (MNREAD) with best near correction. RESULTS: The mean total scores from the NEI VFQ-25 were 47.8 ± 15.8 in the RP group and 94.8 ± 4.3 in the control group (P < .001 for total and subscale scores). The mean total score and the social functioning and dependency scores were higher in the men than in the women (P = .016). The NEI VFQ-25 scores increased when reading speed was above 80 words per minute (wpm). Positive correlations were found between the degree of the central visual field and the mean total score and the general vision, near, and distance activities; social functioning; mental health; role difficulties; dependency; and color vision scores. The factors that affected the NEI-VFQ-25 score the most were male sex and degree of the central visual field in the RP group, whilst education level and the presence of systemic disease were the most effective factors in the controls. CONCLUSION: The only modifiable factor affecting vision-related QoL in patients with RP was reading speed; thus, QoL could improve if reading speed is increased in patients with RP.

Ophthalmologic approach to babies with cerebral visual impairment.

BACKGROUND: Cerebral visual impairment (CVI) is an increasingly common type of visual disturbance in infants and children. The increased incidence is associated with improved neonatal intensive care services and survival of premature infants, especially in developed countries and our country. For accurate ophthalmological evaluation, it is important to know the behavioral responses to visual stimuli that are unique to CVI such as color preference, need for movement, visual latency, visual field preference, and difficulty in visual complexity. METHODS: This review is prepared to draw attention to the subject within the scope of Ankara University Vision, Artificial Vision and Low Vision Rehabilitation training programs. RESULTS: The most common causes are hypoxia and perinatal ischemia. Ocular structures are generally normal or are not sufficient to explain the visual impairment. Diagnosis and habilitation methods differ from visual impairment of ocular origin. As a result, early diagnosis of CVI in infants and toddlers and an effective visual habilitation with a multidisciplinary approach where ophthalmologists and pediatricians lead the team is very valuable. CONCLUSIONS: Early diagnosis and early visual habilitation will increase the quality of life of babies and will provide important gains for families and therefore the whole society. Pediatricians should be familiar with this group of disturbances and the available resources, as they are best placed to refer the child for evaluation and rehabilitation and encourage the family for follow-up.

How Much Do Clinical and Microperimetric Findings Affect Reading Speed in Low Vision Patients with Age-related Macular Degeneration?

Purpose: To investigate the factors affecting the reading speed of patients with central scotoma due to age-related macular degeneration (AMD).Materials and Methods: We included 63 eyes of 63 patients with AMD who applied to our low vision clinic between August 2018 and September 2019 in this prospective study. We evaluated socio-demographic characteristics, eye examination findings and Minnesota Low Vision Reading Test (MNREAD) results. We used the MAIA microperimeter device to evaluate the properties of the preferred retinal locus for fixation (PRL) of the patients. Evaluations included the assessment of the effects of all parameters on reading speed.Results: The PRL was most commonly in the nasal (31%) and superior (26%) quadrants. Twenty-nine percent of the cases preferred the left visual field. PRL localization had no effect on reading speed, whereas, fixation stability, educational status, presence of foveal absolute scotoma, reading acuity and duration of reading interruption were found to have the most significant effects. Multiple regression analysis showed that reading speed decreased by 67 units in the presence of unstable fixation, by 17 units in the presence of foveal absolute scotoma, by 3 units with every 0.1 increase in logMAR value, and by 1.7 units with every 1-year increase in reading interruption. Additionally, being a university graduate was associated with an increased reading speed (by 18 units)Conclusion: Increased reading performance is one of the factors that can improve quality of life. The factors found to affect the reading speed in the current study may guide the rehabilitation process in low vision patients.

Effectiveness of Low Vision Rehabilitation Using Microperimetric Acoustic Biofeedback Training in Patients with Central Scotoma.

PURPOSE: To evaluate the efficacy of visual rehabilitation with microperimeter biofeedback in patients with central scotoma. MATERIALS AND METHODS: 35 consecutive patients with central scotoma (17 age-related macular degeneration (AMD), 14 Stargardt disease, and 4 cone dystrophy) were included in the study. Visual acuity, reading performance by Minnesota Low Vision Reading Test (MNREAD), quality of life by 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25), and fixation analysis by MAIA microperimeter were evaluated before and 1 month after training. The rehabilitation program consisted of 10 training sessions of 10 minutes. RESULTS: The median best-corrected visual acuity (BCVA) was 0.80 logMAR (range 0.3 to 1.3 logMAR). Fifty-nine percent of patients with AMD developed a preferred retinal locus (PRL) nasal to the fovea, and 64% of the patients with Stargardt disease preferred a PRL superior to the fovea. The PRL location in 3 of 4 cone dystrophy patients was nasal to the fovea. The mean PRL distance from the fovea was 7.57 ± 3.61 degrees. Fixation stability improved with P1 values of 22.34 ± 11.81 versus 32.05 ± 18.79 (p = .003) and 95% bivariate contour ellipse area (BCEA) values of 41.6 versus 23.6 (p = .018) before and after training, respectively. There was a significant difference in reading acuity between before and after training (p = 0.008). The overall score and near activities score of NEI VFQ-25 were found to be increased at the end of the rehabilitation (p < 0.001). CONCLUSION: Rehabilitation with acoustic biofeedback in patients with central scotoma looks like a useful technique for improving fixation stability, reading performance and quality of life.

A different surgical approach to cases with zonular weakness or dialysis: sutureless transscleral fixated intraocular lens implantation and stabilization of lens capsule.

PURPOSE: To evaluate the effect of sutureless transscleral fixated intraocular lens (IOL) implantation and capsule stabilization of IOL optics on postoperative visual outcomes in cases with zonular dialysis in excess of 70°. METHODS: Fifteen eyes of thirteen patients with > 70° zonular dialysis and endothelial cell counts higher than 1500 cells/mm2 who had been followed for at least 6 months were included. A modified surgical approach was applied to these eyes with sutureless transscleral fixated IOL implantation and the IOL was secured to the capsulorhexis to stabilize the lens capsule (optic capture). RESULTS: The mean best-corrected visual acuity (BCVA) was 0.21 ± 0.2 on the first day, 0.45 ± 0.33 on the first week, 0.60 ± 0.32 on the first month, 0.80 ± 0.26 on the third month, and 0.82 ± 0.27 on the sixth month. When preoperative BCVA and postoperative BCVA were compared, a statistically significant increase was observed in postoperative BCVA beginning from the seventh postoperative day. There was a statistically significant (p = 0.038) decrease in endothelial cell count at postoperative third and sixth months (1895 ± 65, 1872 ± 376, respectively) compared to preoperative values. CONCLUSIONS: The use of this new surgical modification that utilizes capsular tension rings combined with a procedure that secures the sutureless scleral IOL fixation to the capsulorhexis for the treatment of eyes with zonular dialysis in excess of 70° was found to be very successful in the 6 months of follow-up. More cases and longer follow-up periods are required to provide an idea as to whether different complications will develop in such patients.

Current Approaches to Low Vision (Re)Habilitation

With increased life expectancy at birth and especially the rising incidence of age-related macular degeneration, low vision (re)habilitation is becoming more important today. Important factors to consider when presenting rehabilitation and treatment options to patients presenting to low vision centers include the diagnosis of the underlying disease, the patient's age, their existing visual functions (especially distance and near visual acuity), whether visual loss is central or peripheral, whether their disease is progressive or not, the patient's education level, and their expectations from us. Low vision patients must be guided to the right centers at the appropriate age, with appropriate indications, and with realistic expectations, and the rehabilitation process must be carried out as a multidisciplinary collaboration.

The Evaluation of Reading Performance with Minnesota Low Vision Reading Charts in Patients with Age-related Macular Degeneration.

PURPOSE: To evaluate the reading performance using the Minnesota low vision reading (MNREAD) charts, of patients with age-related macular degeneration (AMD) who use low vision aid (LVA) devices. MATERIALS AND METHODS: This prospective study enrolled 27 patients with AMD. Distance visual acuity (VA) was evaluated with a distance chart designed for patients with low vision. Near vision and reading performance were evaluated with the Turkish version of the MNREAD charts. Unaided vision and vision with LVA devices and high spherical add near glasses was measured. P <0.05 was considered statistically significant. RESULTS: The mean unaided near VA was 1.05 ± 0.27 log of the minimum angle of resolution (LogMAR). The mean VA with the LVA devices was 0.71 ± 0.41 LogMAR. Reading acuity ranged between 1.15 and 0.21 LogMAR, critical print size was between - 1.2 and 0.2 LogMAR. Maximum reading speeds were between 0 and 103 words/min. The cases are divided into groups in terms of reading speed according to age, gender, diagnosis, and education. Reading speed was negatively correlated to increasing age. CONCLUSION: MNREAD reading charts can be used to evaluate reading performance in patients with AMD with low vision. The outcomes of the present study indicate that optical correction is adequate for near VA requirements in this patient population. However, optical correction was inadequate for improving reading performance. Appropriate rehabilitation programs can be used to increase reading speed.