Video-oculographic Analysis in Nystagmus Patients

Purpose@#To evaluate the usefulness of video-oculographic waveform analysis in nystagmus patients. @*Methods@#We carried out an observational case study in 18 patients (age, 7-32 years) with nystagmus who visited our clinic regularly for more than 1 year. Video-oculography (VOG) recording was performed (SLVNG®; SLMED, Seoul, Korea/3D Video-Oculography®; SMI, Teltow, Germany), and the velocity, peak velocity, and frequency of ocular movement were evaluated. The results of VOG analysis were compared to the diagnosis based on clinical examination and video recording. @*Results@#Eleven patients showed corresponding results, while the results differed between presumed diagnosis by VOG waveform analysis and clinical diagnosis in seven patients. Two of the discordant group showed additional waveforms that were not found on clinical examination. In addition, the number of inverse cases was two. The VOG waveform results corresponded to the diagnosis based on video recording in 16 patients. @*Conclusions@#Video-oculography is useful for diagnosis and management of nystagmus patients as it is noninvasive, comfortable, and can be performed in patients with difficulties with electronystagmography, such as pediatric patients. In addition, its waveform analysis and quantification are reliable taking into consideration diagnosis based on clinical examination and video recording.

Regressed Retinal Astrocytic Hamartomas in Tuberous Sclerosis by Mammalian Target of Rapamycin Inhibitor (Everolimus) Treatment

Purpose@#We report a case of regressed retinal astrocytic hamartomas (RAHs) in tuberous sclerosis complex (TSC) patients by mammalian target of rapamycin inhibitor (everolimus) treatment. Case summary: A 12-year-old girl diagnosed with TSC visited for regular checkups. The patient had undergone regular fundus examinations every year after the finding of multiple RAHs in both eyes in the initial screening at 3 months of age. There was no change in the size or thickness of the lesions until she reached 10 years of age. Two months later, the patient started systemic everolimus (5 mg, AFINITOR®, Novartis, Basel, Switzerland) treatment for 17 months under the care of a pediatric neurologist for seizure control. Subsequent fundus examination and measurements by optical coherence tomography showed improvement in the maximal thickness of all lesions, specifically, a reduction of 25%. @*Conclusions@#mTOR inhibitors are targeted agents that regress systemic hamartomas and control convulsions without serious side effects in TSC patients. The particular one used in this study, Afinitor everolimus, reduced the RAH size in our patient. Thus, in cases where an RAH affects vision due to its location, everolimus can considered as a therapeutic option.

Video-oculographic Analysis in Nystagmus Patients

Purpose@#To evaluate the usefulness of video-oculographic waveform analysis in nystagmus patients. @*Methods@#We carried out an observational case study in 18 patients (age, 7-32 years) with nystagmus who visited our clinic regularly for more than 1 year. Video-oculography (VOG) recording was performed (SLVNG®; SLMED, Seoul, Korea/3D Video-Oculography®; SMI, Teltow, Germany), and the velocity, peak velocity, and frequency of ocular movement were evaluated. The results of VOG analysis were compared to the diagnosis based on clinical examination and video recording. @*Results@#Eleven patients showed corresponding results, while the results differed between presumed diagnosis by VOG waveform analysis and clinical diagnosis in seven patients. Two of the discordant group showed additional waveforms that were not found on clinical examination. In addition, the number of inverse cases was two. The VOG waveform results corresponded to the diagnosis based on video recording in 16 patients. @*Conclusions@#Video-oculography is useful for diagnosis and management of nystagmus patients as it is noninvasive, comfortable, and can be performed in patients with difficulties with electronystagmography, such as pediatric patients. In addition, its waveform analysis and quantification are reliable taking into consideration diagnosis based on clinical examination and video recording.

Regressed Retinal Astrocytic Hamartomas in Tuberous Sclerosis by Mammalian Target of Rapamycin Inhibitor (Everolimus) Treatment

Purpose@#We report a case of regressed retinal astrocytic hamartomas (RAHs) in tuberous sclerosis complex (TSC) patients by mammalian target of rapamycin inhibitor (everolimus) treatment. Case summary: A 12-year-old girl diagnosed with TSC visited for regular checkups. The patient had undergone regular fundus examinations every year after the finding of multiple RAHs in both eyes in the initial screening at 3 months of age. There was no change in the size or thickness of the lesions until she reached 10 years of age. Two months later, the patient started systemic everolimus (5 mg, AFINITOR®, Novartis, Basel, Switzerland) treatment for 17 months under the care of a pediatric neurologist for seizure control. Subsequent fundus examination and measurements by optical coherence tomography showed improvement in the maximal thickness of all lesions, specifically, a reduction of 25%. @*Conclusions@#mTOR inhibitors are targeted agents that regress systemic hamartomas and control convulsions without serious side effects in TSC patients. The particular one used in this study, Afinitor everolimus, reduced the RAH size in our patient. Thus, in cases where an RAH affects vision due to its location, everolimus can considered as a therapeutic option.

Long-term Changes in Refractive Error after Spectacle Use

PURPOSE: To evaluate the long-term changes in spherical equivalent (SE) refractive error and astigmatism in patients after spectacle use. METHODS: A total of 103 patients with refractive error without strabismus and amblyopia who received at least 3 years of follow-up after using spectacles were included in this study. Patients were divided into groups according to the age at which spectacles were used (+0.75 D), and the initial degree of astigmatism (<1.00 D, 1.00 to 3.00 D, ≥ 3.00 D). Changes in the SE refractive error and astigmatism were compared between these groups using mixed linear models.. RESULTS: Patients were followed up for a mean of 9.1 ± 1.6 years. An overall negative shift in SE refractive error and an increasing tendency in astigmatism during follow-up were noted regardless of the age at which spectacles were used (p < 0.001). The myopic group showed the largest negative shift in SE and the largest increase in astigmatism (p < 0.001, p = 0.02 respectively). The low and moderate astigmatism groups were more likely to have significant increases in astigmatism (p < 0.001). CONCLUSIONS: Patients with refractive error showed a negative shift in SE and an increasing tendency in astigmatism regardless of the age at which spectacles were used. Changes in SE and astigmatism may be influenced by the initial degree of SE, and the initial degree of astigmatism may influence changes in astigmatism.

Prevalence and Factors Associated with the Use of Eye Care Services in South Korea: Korea National Health and Nutrition Examination Survey 2010–2012

PURPOSE: To estimate the factors and prevalence of eye care service utilization in the South Korean population. METHODS: This cross-sectional, population-based study included data from 22,550 Koreans aged ≥5 years who participated in the Korea National Health and Nutrition Examination Survey from 2010 to 2012. For people aged 5 to 11 years (young children), information was based on self-reports of contact with eye care service in the past year; for people aged ≥12 years (older population), the information was based on the self-reported lifetime contact with eye care service. Univariate and multivariate logistic regression analyses of the complex sample survey data were performed. RESULTS: The prevalence of eye care service use in young children during the past year was 61.1% (95% confidence interval, 58.1%–64.1%), while that in the older population during their lifetime was 73.5%. Subjects aged 7 to 11 years were more likely to have had an eye examination in the past year than subjects aged 5 to 6 years (odds ratio, 3.83; 95% confidence interval, 2.37–6.19). Multivariate logistic regression analysis indicated that higher monthly household income, being a National Health Insurance holder, and having private health insurance were related to more frequent use of eye care services in young children. For the older population and women, those living in an urban area and those with a best-corrected visual acuity less than 20 / 40 in the worse-seeing eye were more likely to have had an eye examination during their lifetime. Low education level was associated with low lifetime use of eye care services in the older population. CONCLUSIONS: There are sociodemographic disparities with use of eye care services in South Korea. This population-based study provides information that is useful for determining different intervention programs based on sociodemographic disparities to promote eye care service utilization in South Korea.

Optical Coherence Tomography Findings of Optic Nerve Head Drusen in Children and Adolescents

PURPOSE: To analyze the features of optic nerve head drusen (ONHD) observed on the optical coherence tomography (OCT) of pediatric and adolescent patients and to compare the characteristics of diagnosed ONHD pediatric and adolescent patients with the control group. METHODS: We performed a retrospective chart review of pediatric and adolescent patients with nasal elevation or marginal blurring of the optic nerve head on either direct ophthalmoscopic examination or fundus photography. Patients were compared with a control group of the same age who had normal optic nerve heads and no abnormal findings except refractive errors under ophthalmic examination including OCT. RESULTS: There were 29 eyes (n = 16) with ONHD as a subretinal mass-like lesion on OCT among 84 eyes with nasal elevation or marginal blurring of the optic nerve head on OCT. Thirteen patients (18.8%) were diagnosed with ONHD in both eyes. The following 3 groups were compared: group 1, showing nasal elevation or marginal blurring of the optic nerve head on OCT and diagnosed with ONHD; group 2, without ONHD; group 3, normal controls. The spherical equivalent was significantly different among the groups (p < 0.001). Compared with group 3, group 1 showed peripapillary retinal nerve fiber layer thickening of the temporal area; however, there was no difference between groups 1 and 2. CONCLUSIONS: Buried ONHD in children and adolescents may be asymptomatic and the diagnosis can be made when a subretinal mass-like lesion is detected on OCT.

Pharmacologic Effects of Atropine Penalization in Amblyopic Eyes

PURPOSE: To analyze the pharmacologic effect of atropine penalization in amblyopic eyes. METHODS: Distant and near visual acuity, near point of accommodation (NPA), and pupil size were measured in the sound eye of 40 children with amblyopia before and after receiving atropine sulfate 1% solution. Amblyopic children were divided into 2 groups according to the time of follow-up visit: 4-days and 7-days after injection; the same tests were performed on all the scheduled follow-up visits. This study included a control group of 20 normal children who received the same test on the initial visit and the scheduled follow-up visits. RESULTS: Visual acuity of the sound eye at distance showed greater decreases in children with 4-day follow-up visits compared with 7-day visits in the amblyopic group (p = 0.24). There was no significant difference in near visual acuity between the amblyopic group and the normal control group by follow-up interval (p = 0.98, p = 0.75). Near point of accommodation significantly increased in the 4-day visit group in both the amblyopic and the normal control groups (p = 0.04 and p = 0.03, respectively), Pupil size was significantly maintained in the 4-day visit, amblyopic group (p = 0.01). CONCLUSIONS: Atropine effectively decreased the vision of the sound eye in amblyopic children. However, to maintain the pharmacologic effect, two separate atropine instillations per week (on a weekday and the weekend) should be considered as a treatment for amblyopia.

Relationship among Dominant Eye & Hand and Deviated Eye under General Anesthesia

PURPOSE: To evaluate the association between ocular dominance, hand dominance and eye deviation in orthophoric and strabismus patients under general anesthesia during surgery. METHODS: The subjects were divided into 2 groups. Group 1 was composed of 38 patients who underwent strabismus surgery and group 2 was composed of 107 patients who underwent non-strabismus surgery under general anesthesia. Best corrected visual acuity (BCVA), dominant hand and fixating eye were obtained before surgery, and ocular dominance was assessed using the hole-in-the-card test. Under general anesthesia, we took a digital photo of both eyes, and the deviating eye was determined. RESULTS: Under general anesthesia, the deviated eye showed no statistically significant correlation to the dominant eye and dominant hand in group I, respectively (p = 0.61, 0.74, respectively). In group II, there was no correlation between the deviated eye and the dominant eye (p = 0.65). The deviated eye also showed no correlation to the dominant hand in group II (p = 0.61). CONCLUSIONS: There was no correlation between the dominant and deviated eye under general anesthesia in the strabismus surgery group and the non-strabismus surgery group. Also, there was no correlation between the dominant hand and the deviated eye in patients under general anesthesia in the 2 groups.

Comparative Analysis of the Humphrey Static Perimetry and the Goldmann Kinetic Perimetry: Application of the Humphrey Static Perimetry to Visual Disability Evaluation

PURPOSE: In the evaluation of visual field defect, Goldmann kinetic perimetry is the preferred method. However, in many cases, Humphrey static perimetry is performed for visual disability evaluation in Korea. In the present study we investigated the correlation between Goldmann kinetic perimetry and Humphrey static perimetry for disability evaluation using visual field score (VFS). METHODS: This study included 126 eyes, classified into the following groups: 60 eyes, normal group; 11 eyes, contraction of central visual field group; 42 eyes, irregular visual field group; 13 eyes, hemianopsia group. All subjects were examined with Goldmann kinetic perimetry and Humphrey static perimetry. We studied the correlation of the VFS between Goldmann kinetic perimetry and Humphrey static perimetry according to the Korean Academy of Medical Science Guides for Impairment Evaluation (KAMS Guides) and American Medical Association Guides for the Evaluation of Permanent Impairment (AMA Guides). RESULTS: Regarding contraction of central visual field group, Goldmann VFS, Humphrey VFS and extended Humphery VFS showed no statistical significance (AMA: p = 0.50, p = 0.30, KMAS: p = 0.36, p = 0.18. respectively). In the irregular visual field and hemianopsia groups, Goldmann VFS and Humphrey VFS showed statistical significance (AMA: p = 0.00, p = 0.00, KMAS: p = 0.00, p = 0.00. respectively). Goldmann VFS and extended Humphrey VFS showed no statistical significance (AMA: p = 0.13, p = 0.12, KMAS: p = 0.08, p = 0.99. respectively). CONCLUSIONS: The contraction of central visual field based on Humphrey static perimetry can be applied to visual disability evaluation. However, in the majority of cases, there is a difference between the two tests and Goldmann kinetic perimetry should be used first in the evaluation of visual field disability evaluation.

Anthropometric Measurements of Soft-Tissue Orbits in Korean Newborns

PURPOSE: To establish a database of the anthropometric measurements of soft-tissue orbits in Korean newborns. METHODS: A total of 69 normal term newborns (39 males, 30 females) in the first 48 hours after delivery, were included in the present study. Anthropometric measurements of soft-tissue orbits were taken with vernier calipers by one of the authors. With eyes closed, horizontal eyelid fissure length (HFL), lower lid height (LLH), upper lid height (ULH), intercanthal distance (ICD), and inter-outercanthal distance (IOCD) were measured and with eyes opened with a speculum, the interpupillary distance (IPD) was measured. RESULTS: There was no significant difference between either sex or between the right and left eyes. HFL was 20.8 +/- 1.2 mm, LLH and ULH were 11.1 +/- 2.3 and 16.5 +/- 2.5 mm, respectively; ICD, IPD, and IOCD were 22.9 +/- 2.1 mm, 39.8 +/- 3.0 mm, and 65.3 +/- 5.8 mm, respectively. CONCLUSIONS: Anthropometric measurements of normal Korean newborns' soft-tissue orbits in the present study can be used as basic data for the proper evaluation and growth of soft-tissue orbits.

A Study of Driving Behaviors among Patients with Chronic Ophthalmological Disorders

PURPOSE: This study examines driving behaviors among patients treated for chronic ophthalmologic disorders and the effects of visual acuity and visual field on driving performance. METHODS: A 15-item survey was given to 153 patients treated for chronic ophthalmologic disorders including diabetic retinopathy, glaucoma, retinal vessel occlusions, and senile macular degeneration. Six items questioned the patient's discomfort based on a five-point scale according to different driving conditions and one item involved a self-assessment of driving problems. Results were compared with the best corrected visual acuity (BCVA) and visual fields of the patients. RESULTS: In total, 16.2% of first-class drivers and 24.1% of second-class drivers rated below the evaluation standards of the driving license aptitude test. Overall, 82.6% of the patients continued to drive, while 7.8% renounced driving due to decreased visual acuity. Patient discomfort was significantly correlated with visual acuity (r = -0.503, p < or = 0.01). Among the patients scoring below the evaluation standards, 74.2% responded that their visual acuity had become a problem while driving. CONCLUSIONS: These results call for appropriate driving programs and measures to educate people about responsive driving considering the visual function of patients treated for chronic ophthalmologic disorders.

Amblyogenic Risk Factors in Primary Family Members of Patients with Exotropia

PURPOSE: To investigate the prevalence of amblyogenic risk factors in the primary family members (parents, siblings) of patients with exotropia. METHODS: The authors of the present study examined primary family members including parents and siblings of 58 exotropia patients in our clinic. Best corrected visual acuity, refractive error, and cover-uncover test were performed. A total of 49 normal children's family members (control group) were examined in a similar manner. The prevalence of significant ocular findings were determined and compared to the control group. RESULTS: In 58 eligible families (153 subjects except proband), 65.4% had significant ocular findings: In parents, anisometopia, astigmatism, hyperopia, and strabismus were found at a rate of 18.1%, 31.1%, 2.5%, and 11.2%, respectively. In siblings, anisometropia, astigmatism, hyperopia, and strabismus were found at a rate of 24.3%, 24.3%, 5.4%, and 18.9%, respectively. Compared to the control group, in parents of exotropia patients, anisometropia, astigmastim, and strabismus were observed at a higher rate. In siblings, anisometropia, and strabismus were observed at a higher rate. CONCLUSIONS: Primary family members of exotropia patients have a high prevalence of amblyogenic risk factors. The present study offers rationale for providing comprehensive eye exams for parents and children with a family history of exotropia.

Effect of Intracameral Triamcinolone to Control Inflammation in Rabbit Eyes

PURPOSE: To investigate the effect of intracameral triamcinolone on the control of inflammation with rupture of the posterior lens capsule during cataract surgery in rabbit eyes. METHODS: Twenty rabbit eyes were subjected to experimentally induced rupture of the posterior lens capsule and prolapse of the vitreous body into the anterior chamber. After anterior vitrectomy with and without triamcinolone, aqueous flare was measured with a laser flare meter on days 1, 3, 7, 14 and 28. RESULTS: Vitrectomized eyes with triamcinolone showed a less marked increase in postoperative aqueous flare intensity on days 14 and 28 than did those without triamcinolone (p<0.05). CONCLUSIONS: Intracameral injection of triamcinolone was beneficial for visualizing the prolapsed vitreous in the anterior chamber and for helping to control the postoperative inflammation without adverse effects.

10-Prism-Diopter Fixation Test for Amblyopia

PURPOSE: To evaluate the clinical usefulness of the 10-prism-diopter (PD) fixation test in the diagnosis of amblyopia. METHODS: The study comprised 132 children (42 normal, 90 amblyopes) who underwent the 10-PD fixation test and stereoacuity test. The sensitivity, specificity, false-positive and false-negative rates of the 10-PD fixation test were analyzed according to the clinical diagnosis. RESULTS: The 10-PD fixation test sensitivity was 86%, the specificity was 61%, the false-positive rate was 17% and the false-negative rate was 24%. Data showed agreement between the 10-PD fixation test and the stereoacuity test (gamma=0.737, p=0.000). The results in the 10-PD base-down test and base-out test also showed agreement (gamma=0.779, p=0.000). CONCLUSIONS: The 10-PD fixation test is a simple and useful method in detecting amblyopia.

The Meaning of Monocular Occlusion on Preoperative Evaluation in Basic Intermittent Exotropia

PURPOSE: To assess the clinical potential of one-hour monocular occlusion on preoperative alignment evaluation in basic intermittent exotropia. METHODS: Twenty-nine patients with basic intermittent exotropia who were preoperatively examined for one-hour monocular occlusion were selected (monocular occlusion group). Their records were reviewed retrospectively. The measured angle after one hour of monocular occlusion was used to determine the surgical target angle. The control group consisted of 29 patients whose age, sex and control state were similar to the monocular occlusion group. Measurement of the angle of strabismus was not done in the control group. Surgery was performed for the measured angle at six meters. The results of surgery were used to compare the groups relative to the control state. RESULTS: Fifteen patients (51.7%) had an increase in the distance deviation after one hour of monocular occlusion. Of the patients with good control, 78.6% (11/14) had an increase in the angle of misalignment. Only 26.7% (4/15) of patients with poor control experienced a change in the angle deviation (p<0.05). In all, 79.3% of patients in the study group and 75.9% of those in the control group had a satisfactory surgical outcome. Among the patients with good control, 85.7% of patients who underwent surgery for increased angle had a satisfactory outcome, compared with 71.4% of patients who underwent surgery for initial angle (p=0.375). CONCLUSIONS: One-hour monocular occlusion might help to prevent undercorrection after surgical treatment by identifying the hidden deviation, especially in the patients whose control over the distance deviation was good.

Comparison of the Normal Visual Fields Between the Goldmann and Humphrey Kinetic Perimetries

PURPOSE: To show Humphrey automated kinetic perimetry can be substituted for Goldmann perimetry, which has been used in the field of disability evaluation field, the differences of normal visual fields between two perimetries were evaluated. METHODS: Goldmann and Humphrey automated kinetic perimetries were performed simultaneously in 70 eyes of 35 normal healthy Koreans who had no specific ophthalmologic disease at 12 meridians; 0degrees, 30degrees, 60degrees, 90degrees, 120degrees, 150degrees, 180degrees, 210degrees, 240degrees, 270degrees, 300degrees, and 330degrees. The mean values of field in each case were compared. In addition, the corrected values were obtained through the calculation of the difference in the two maximal fields. RESULTS: The visual fields of Humphrey and Goldmann kinetic perimetries showed a similar oval shape, but the fields of Goldmann were statistically significantly wider than the Humphrey fields. As the values of Humphrey were compared with the original data of Goldmann, all values of the visual field were narrow. CONCLUSIONS: The visual fields by Humphrey automated kinetic perimetry were smaller than those by Goldmann perimetry. Therefore, if Humphrey kinetic perimetry is used for the evaluation of visual disability, the visual field should be evaluated after the correction.

Guideline Development for the Evaluation of Visual Impairment in Korea

This guideline is developed to provide criteria for evaluating permanent impairment of the visual system as it affects an individual's ability to perform activities of daily living. This new assessment system is based on the 5th and 6th edition of American Medical Association and McBride impairment assessment system but revised on the consideration of Korean culture and simple application. This evaluation of impairment is based on an assessment of visual acuity and visual field. Especially it weighs binocular vision and binocular visual fields and the binocular vision and binocular visual fields provide 50% of weight and the right and left eye each contribute 25%. A further adjustment of the impairment rating is included at the final step of this evaluation. Functional deficits for individual adjustments include diplopia, problem of accommodation, abnormality of eyelids, tearing, cosmetic problems from cornea opacity, glare, aphakia, and dark-adaptation. The adjustment can be added to impairment rating up to 15%. Further study is necessary to revise and update of this disability evaluation that have potential problems in actual application.

Correlation of OCT and Hemifield Pattern VEP in Hemianopia

PURPOSE: To analyze the correlation between RNFL thickness changes measured by OCT and hemifield pattern VEP in hemianopic visual field loss. METHODS: Twelve eyes of six patients with hemianopia were studied. Two patients had bitemporal hemianopia caused by chiasmal tumor, one patient had inferior hemianopia caused by traumatic optic neuropathy, and three patients had homonymous hemianopia caused by occipital lobe lesions. The retinal nerve fiber layer thickness around the optic disc was measured by optical coherence tomography (OCT) and visual pattern evoked potentials were measured using hemifield stimulations. RESULTS: Normal eyes of traumatic optic neuropathy patients were excluded from the analysis. The retinal nerve fiber layer thickness as measured by OCT corresponded to the visual field defect in 9 of 11 eyes (81.8%) and the hemifield pattern VEP response corresponded to visual field defect in 7 of 11 eyes (63.6%). CONCLUSIONS: RNFL thickness measurement by OCT and hemifield PVEP are useful in evaluation of patients with hemianopia. However, they should be performed with caution, and compared with various clinical examinations because of their incomplete correlation with visual field defects.

Comparison of Results of Cryopexy and Laser Indirect Ophthalmoscopy in Rhegmatogenous Retinal Detachment

PURPOSE: To compare the efficacy and safety of intraoperative laser indirect ophthalmoscopy and cryopexy for rhegmatogenous retinal detachment through the use. METHODS: We retrospectively analyze the clinical results of 60 patients (61 eyes) with rhegmatogenous retinal detachment. All eyes had an attached macula and were scheduled for conventional scleral buckling surgery with cryopexy (25 eyes) or laser indirect ophthalmoscopy (36 eyes) from March 2001 to August 2007. The visual acuities of the two groups at the first postoperative day, 1 week, 1 month, and 3 months were compared. Retinal reattachment, macular pucker, cystoid macular edema, and proliferative vitreoretinopathy were confirmed 3 months after surgery. RESULTS: The visual recovery was faster in patients who received laser indirect ophthalmoscopy (1 day, P=0.044; 1 week, P=0.017). During the follow-up period, anatomical failure in the laser indirect ophthalmoscopy group did not develop, but there were two anatomical failures in the cryopexy group. In addition, 1 PVR was detected in the cryopexy group. However, neither group exhibited macular pucker or cystoid macular edema. Postoperative additional laser photocoagulation was performed on 7 eyes (19.4%) in thelaser indirect ophthalmoscopy group and 2 eyes (4.0%) in the cryopexy group. CONCLUSIONS: Although intraoperative laser indirect ophthalmoscopy causes less chorioretinal scar formation than cryopexy, it has a higher anatomical success rate and allows for faster visual recovery.