Purpose: To evaluate role of axial length in Central Retinal Vein Occlusion (CRVO). Patients and Methods: The study group consisted of 30 patients with unilateral CRVO (19 ischemic & 11 nonischemic). The control group included 29 individuals who matched the study group patients in age, sex systemic hypertension and diabetes mellitus status.The axial lengths of affected and fellow eyes of patients and controls were measured using A-scan ultrasonography.Results: The mean axial length of affected eyes was not statistically significantly shorter than that of unaffected eyes in the CRVO group (22.88mm vs 22.90 mm) & its two ischemic & nonischemic subgroups (P>0.05). There were not statistically significant differences in axial length between control eyes and affected eyes in the CRVO group (23.11mm vs 22.88mm) & ischemic & nonischemic subgroups (P>0.05) as well.Conclusion: Our study did not demonstrate a significantly shorter axial length in CRVO eyes without macular edema. Axial length as a measurement of axial hyperopia may not be a risk factor for CRVO.

Purpose: To evaluate the effect of interocular axial length (AL) difference on outcomes of treatment for anisometropic amblyopia in comparison with normal participants. Methods: In this historical cohort study, 83 patients with anisometropic amblyopia were divided into two age groups, 70 children (mean, 7. 86 ± 1. 56 and range, 5–15 years) and 13 adults (mean, 26. 46 ± 10. 87 and range, 16–45 years). The control group consisted of 43 non-amblyopic children and 17 non-amblyopic adults. Treatment outcomes after a period of one year were defined as successful or unsuccessful when posttreatment amblyopic corrected distance visual acuity (CDVA) was reported as ≤0. 9 versus CDVA ≤ 0. 8, respectively. AL was measured using a Lenstar LS900 (Haag-Streit AG, Switzerland). Results: Fifty-nine patients showed satisfactory treatment outcomes (55 children and 4 adults), while unsuccessful treatment outcomes were observed in 24 patients (15 children and 9 adults). The mean of amblyopia treatment duration was 1. 24 ± 0. 76 years. The mean of interocular AL difference in all patients, control, successful and unsuccessful treatment outcome groups were 0. 49 ± 0. 70mm (range, 0. 00–3. 89 mm), 0. 12 ± 0. 07 mm (range, 0. 02–0. 41), 0. 33 ± 0. 23 mm (range, 0. 00–0. 99 mm), and 1. 81 ± 0. 80 mm (range, 1. 14–3. 89 mm), respectively. In both age groups, the mean of interocular AL difference in patients with unsuccessful treatment outcomes was greater than those with successful treatment outcomes and that of the control group (P < 0. 001). Conclusion: The results of this study suggest that the outcome of anisometropic amblyopia treatment may depend on the interocular AL difference.

Purpose: To assess the repeatability of Pentacam AXL as a Scheimpflug-based system or measuring axial length according to the age, sex, lens type, axial length value, and type of cataract. Methods: The present study was conducted using multistage cluster sampling in Tehran, Iran. Ocular biometry was performed, using the Pentacam AXL, by an experienced optometrist on all the participants. The axial length (AL) measurements were taken thrice, with a gap of 10 minutes. To evaluate the repeatability, the intraclass correlation coefficient (ICC) and the repeatability coefficient (RC) were calculated. To determine the significant difference in the repeatability index among study variables, the tolerance index (TI) was calculated. Results: In this report, 897 eyes of 677 individuals aged between 20 and 91 years (mean ± SD: 64. 90 ± 13. 62 years) were reported. The ICC of the axial length measurements was 0. 981 for all cases. Based on the within-subject standard deviation, the RC was 0. 401. The ICC was 0. 976 and 0. 985 in men and women, respectively. The TI showed better RC of measurements among females. The ICC decreased from 0. 999 in participants under 40 years to 0. 973 in individuals over 60 years of age. The TI showed a decrease in RC with advancing age. The RC was worse in eyes with nuclear cataracts,the RC was also worse in the first quartile of the signal-to-noise ratio (SNR) compared to the other SNR quartiles. Conclusion: The Scheimpflug-based system Pentacam AXL had high repeatability in measuring axial length. Some variables such as male gender, older age, and nuclear cataract were associated with reduced repeatability of the measurements. A higher SNR was associated with better repeatability of the axial length measurements.

Objective: To determine the association between the axial length of the eye and retinal vein occlusion [Branch Retinal Vein Occlusion (BRVO) and Central Retinal Vein Occlusion (CRVO)].Method: 18 patients with CRVO and Hemi-Retinal Vein Occlusion (hemiRVO) and 18 patient with BRVO were selected and 18 patient who referred for cataract extraction were matched with cases as control group. Axial length was measured in both eyes in cases and controls with A-scan biometry. The data were analysed according to student t test.Results: The affected and fellow eyes in CRVO group differ significantly in axial length (P=0.007). In BRVO group this difference was less but still significant (P=0.048). The axial length of non affected eye of CRVO and BRVO groups is lower than control group with P=0.047 & P=0.017 respectively. In BRVO group mean axial length of the affected eyes was 22.52 mm (80=0.72) and mean axial length of the fellow eyes was 22.77 mm (80=0.64). In CRVO group mean axial length of the affected eyes was 22.71 mm (80= 0.85) and mean axial length of the fellow eyes was 23.23 mm (80=0.71).In control group mean axial length was 23.77 mm (80=1.02).Conclusion: In our study the affected eyes in both groups were smaller than the fellow eyes, this difference in CRVO group is more pronounced. However this study could not clarify that this difference is either the cause or the effect of the vein occlusion, on the other hand even the fellow eye in BRVO & CRVO group is smaller in axial length than control eyes.

Purpose: To compare axial length (AL) changes after trabeculectomy with mitomycin C (MMC) measured using two methods, contact and non-contact biometry.Methods: Thirty-four eyes of 31 glaucoma patients who were candidates for primary trabeculectomy were enrolled. AL was measured using A scan ultrasound biometry (UD-6000 Ultrasonic A/B scanner biometer, TOMEY) and non-contact optical biometry device (LenStar LS 900, Haag Stereit) preoperatively and 3 and 6 months postoperatively. Postoperative values, measured at 3 and 6 months, were compared with the preoperative values.Results: After trabeculectomy, AL decreased by 0.21±0.16 mm and 0.14±0.13 mm at month 3 and 0.19±0.15 and by 0.14±0.15 mm at month 6 after surgery using A scan and LenStar, respectively (P<0.001 for all comparisons). The mean reduction in AL was significantly lower with LenStar compared with A scan with a mean difference of 0.07±0.15 mm (P=0.011) at month 3 and 0.04±0.09 mm (P=0.02) at month 6.Conclusion: LenStar can provide more accurate AL measurements than A scan which is attributable to the elimination of false AL reduction caused by the effect of contact biometry probe on softened eyes after trabeculectomy.

Purpose: To evaluate the effect of childhood corneal opacity on the anteroposterior length of the globe in adulthood.Methods: Twenty-three patients with significant unilateral corneal opacity which had developed before the age of 6 years and the normal fellow eyes (controls) were evaluated. A comprehensive ocular examination including measurement of anterioposterior length and anterior chamber depth was performed.Results: Mean age was 65.9±12.9 years. Mean axial length was 25.45±2.47 mm in affected eyes vs 22.85±3.34 mm in normal fellow eyes (P=0.001). The difference in axial length was attributed to elongation of the vitreous cavity in affected eyes (18.91±2.82 vs 15.71±2.73 mm, P<0.001).Conclusion: Corneal opacity in childhood can result in axial myopia in adulthood due to elongation of the posterior segment.

Purpose: To comparethe intraocularlens (IOL) power, keratometricvalues, and axial length of both eyes.Methods: In a case series, 100 patients were selected by simple randomized sampling. Keratometry was performed by Goldman keratometer, axial length was measured with contact method, and PC IOL power was calculated with A constant 118.5 by SRK II formula in both eyes of all patients.Inclusion criteria were axial length of 22-26mm, anisometropia≤0.50 diopter, age 2≥15 years, and good patient cooperation. The values of both eyes were compared and statistically analysed.Results: Keratometry, axial length, and intraocular lens power of fellow eyes had no clinically significant differences. Axial length of eyes in men was significantly longer than women. Mean keratometric values of women's eyes was significantly more than men. There was no significant difference in intraocular lens power between men and women. The IOL power difference was≤1 diaper in 89% of cases and≤2 diapers in 99%. The IOL power difference was 0.61±0.65 diopter in women and 0.45±0.53 diaper in men which was not statistically significant.Conclusion: There are usually acceptable results of IOL power calculation by using fellow eye criteria. This can be used in medium sized eyes with less than 0.5 diaper anisometropia. Sometimes there is a surprise result, which may be related to precision of used formula or experience of exammer.