Journal of Ophthalmic and Vision Research
Year:2008 | Volume:3 | Issue:1|Papers Count:11

Purpose: To determine the effect of horizontal rectus muscle surgery on visual acuity, head posture and electronystagmographic indices in patients with congenital nystagmus. Methods: This prospective comparative case series was conducted on 58 patients with congenital nystagmus over a period of three years. Patients were divided into three groups: the first group (29 cases) had head posture less than 20°, binocular visual acuity (BOVA) less than 20/30 and tropia less than 30D and underwent large recession of all four horizontal rectus muscles; the second group (23 cases) had head posture less than 20°, BOVA< 20/30 and tropia more than 30D who underwent large recession of two horizontal rectus muscles; and the third group (6 cases) had head posture more than 20° with any BOVA or tropia who underwent Kestenbaum-Anderson surgery.Results: Mean age of the patients was 18.7±9.1 years and mean follow-up period was 17.5±7.4 months. Visual acuity improved in all three study groups and was statistically significant in the 2-rectus group (P<0.001). The speed and amplitude of nystagmus waves decreased in all groups which was statistically significant in the 4-rectus group (P values, 0.02 and 0.04, respectively). A small myopic shift was seen in the 2-rectus and 4-rectus groups and a small hyperopic shift was found in the Kestenbaum-Anderson group. Statistically significant improvement was achieved in eye deviation in the 2-rectus group and in head posture in the Kestenbaum-Anderson group (P<0.001).Conclusion: Horizontal recti surgery in congenital nystagmus can improve visual acuity, ocular deviation and abnormal head posture, which is particularly marked with 2-rectus recession. Electronystagmographic indices improve especially with 4-rectus recession.

Purpose: To determine the correlation between interpupillary distance (IPD) and innerouter intercanthal distance (IOICD) and to find a regression equation for calculating IPD based on IOICD measurements.Methods: The study subjects were randomly selected from individuals aged 3 months to 20 years who were referred to our ophthalmology clinic, health care centers and children attending kindergartens. Participants were divided into 4 age categories: £3, 3-5, 5-12.5 and 12.5-20 years. IPD was measured by a PD meter (PD2, Oculus, Germany); other parameters including IOICD, nasal limbus to temporal limbus (NLTL), inner intercanthal distance (IICD) and outer intercanthal distance (OICD) were measured using a translucent plastic ruler. Results: The study included 254 female (60.6%) and 165 male (39.4%) subjects with mean age of 87.7±73.2 (range 3-240) months. Significant correlation was observed between IOICD and IPD in the 3-5 yr and 12.5-20 yr age groups. In the £3 and 5-12.5 year age groups, NLTL had the best correlation with IPD. The regression equations for calculating IPD according to IOICD were as follows. In male subjects, near IPD= 0.941×IOICD (r²= 0.98, P<0.001) and for female subjects, near IPD= 0.948×IOICD (r²= 0.98, P<0.001).Conclusion: IPD and IOICD measurements are strongly and positively correlated; IOICD measurements are simpler to obtain and may be used to calculate IPD readings which are more difficult to measure by usual methods in children.

Purpose: To evaluate the outcomes of primary pterygium excision with adjunctive amniotic membrane transplantation. Methods: In an interventional case series, consecutive patients with primary pterygia underwent surgical excision with transplantation of preserved amniotic membrane onto bare sclera. Patients were followed for at least 12 months and the results were evaluated in terms of recurrent pterygium growth and complications.Results: Fifty eyes of 50 consecutive patients including 27 male and 23 female subjects with mean age of 43.36±10.88 years were operated. The pterygia extended onto the corneas for 4.69±1.2 (range 3 to 7) mm. Only one eye (2%) demonstrated recurrent pterygium growth which responded to subconjunctival mitomycin C injection. Another eye (2%) developed amniotic membrane retraction which eventually required a second transplantation leading to complete resolution.Conclusion: Primary pterygium excision with amniotic membrane transplantation is a safe and effective surgical technique with low recurrence rate.

Purpose: To evaluate the effect of laser in situ keratomileusis (LASIK) on stereoacuity (SA).Methods: This prospective study includes 200 patients scheduled for LASIK. SA was evaluated preoperatively and one week, one month and three months postoperatively using the Random Dot test. Patients with preoperative SA worse than 480 sec/arc were excluded from the study.Results: The study included 138 female (69%) and 62 male (31%) subjects. Spherical equivalent was -0.5 to -12.0 D. Mean preoperative SA was 124.80±124.64 (range 480-15) sec/arc which deteriorated to 138.30±126.48 sec/arc one week after surgery (P=0.158) but improved to 111.30±112.15 sec/arc (P=0.002) one month and 103.65+112.20 sec/arc (P=0.001) three months postoperatively. Overall, stereoacuity decreased in 9.5%, increased in 32.5% and remained unchanged in 58% of patients (P=0.007). Patients with anisometropia had worse SA; eventually, SA increased in 5 non-amblyopic anisometropic patients.Conclusion: Despite the overall improvement in mean SA after LASIK, a minority of patients experienced decreased SA. Anisometropic patients without amblyopia seem to have a chance for improved SA after LASIK.

Purpose: To compare spherical aberration and contrast sensitivity with two different types of aspheric posterior chamber intraocular lenses (PCIOLs): Tecnis Z9000 versus Akreos AO.Methods: Thirty-four eyes of 34 patients undergoing phacoemulsification for senile cataracts were randomly assigned to implantation of Tecnis Z9000 or Akreos AO PCIOLs. Outcome measures included best-corrected visual acuity (BCVA), spherical aberration (SA) with 4 and 6 mm pupil diameters and contrast sensitivity under photopic and mesopic conditions at spatial frequencies of 1, 2, 5, 10 and 20 cycles per degree (cpd) three months postoperatively.Results: Mean BCVA was 0.08±0.08 logMAR in the Tecnis Z9000 group and 0.11±0.09 logMAR in the Akreos AO group (P=0.33). SA was less with Tecnis than Akreos AO with 4 and 6 mm pupil diameter (0.14±0.10 mm vs 0.28±0.09 mm, P< 0.001 and 0.30±0.18 mm vs 0.33±0.08 mm, P=0.4, respectively). Contrast sensitivity was significantly higher in the Tecnis Z9000 group at 1, 2, 5 and 10 cpd under photopic and at 1, 2 and 10 cpd under mesopic conditions.Conclusion: Tecnis Z9000 IOL seems to entail better visual outcomes in terms of spherical aberration and contrast sensitivity as compared to Akreos AO.

Purpose: To compare the visual outcomes and complications of lensectomy and posterior chamber intraocular lens (PCIOL) implantation with or without posterior capsulotomy and anterior vitrectomy in older subjects with pediatric cataracts.Methods: Seventeen eyes of 12 children aged 10 to 15 years with congenital or developmental cataracts were randomly divided to two groups. Lensectomy and PCIOL (Alcon Acrys of MA60 AC) implantation was performed with (8 eyes) or without (9 eyes) posterior capsulotomy and anterior vitrectomy.Results: Mean age at the time of surgery was 12.3±1.5 (range 10-15) years and mean follow-up period was 18.7±11.2 (range 6-36) months. Posterior capsule opacification developed in three eyes in the non-vitrectomy group; however, media opacification was mild and capsulotomy was not required in any case. All eyes in the vitrectomy group had a clear visual axis at final follow-up (P=0.2). No significant difference was observed between the two groups in term of visual acuity (P=0.3) or complications.Conclusion: Although posterior capsulotomy and anterior vitrectomy seems to be safe in pediatric cataract surgery, it may not be necessary as a routine procedure in older children.

Purpose: To determine the incidence of steroid induced ocular hypertension following myopic photorefractive keratectomy (PRK).Methods: Myopic PRK was performed on 506 eyes of 269 patients. Preoperatively, spherical equivalent refractive error ranged from -1.00 to -5.00 diopters (D) and cylinder was less than 4 D. Baseline intraocular pressure (IOP) before PRK and at different time intervals after the procedure was measured by Goldmann applanation tonometry. IOP readings were corrected according to central corneal thickness as measured by Orbscan pachymetry. For the purpose of the study, corrected IOP >21 mmHg was considered as ocular hypertension.Results: Ocular hypertension developed in 40 (7.9%) eyes overall, which occurred in 16 eyes (40%) 2-3 weeks postoperatively (mean IOP=23.5±3.0mmHg), in 20 eyes (50%) after 4-6 weeks (mean IOP=25.1±4.2 mmHg) and in 4 eyes (10%) 8-12 weeks following PRK (mean IOP=29.0±3.1 mmHg). There was no correlation between the level of IOP rise and preoperative spherical equivalent refractive error. IOP recovered to normal in all eyes after discontinuation of topical steroids and initiation of anti-glaucoma medications. Mean duration of IOP normalization was 28.5±27.7 (range 7-108) days and no instance of steroid-induced glaucoma was observed in any patient. Conclusion: Topical steroids may cause ocular hypertension following PRK. Early detec-tion, prompt treatment and close follow-up are recommended. We suggest measuring IOP in post-PRK patients no later than 10 to 14 days after initiation of corticosteroid treatment.

Purpose: To compare the frequency and severity of retinopathy of prematurity (ROP) among singleton and multiple-birth neonates referred to Farabi Eye Hospital, Tehran- Iran.Methods: In this retrospective study, records of 99 consecutive neonates from multiple gestation pregnancies including 68 twins, 26 triplets and 5 quadruplets who were screened for ROP from 2002 to 2004 were reviewed. The frequency, severity and risk factors for ROP were determined and compared to a group of singletons who were matched in terms of gender, birth weight (BW), gestational age (GA), oxygen therapy, respiratory distress syndrome, blood transfusion, sepsis and phototherapy.Results: ROP was present in 12.1% of multiple-birth neonates as compared to 15.1% of singletons (P=0.53). Threshold ROP was present in 6.1% of multiple-birth neonates versus 7.1% of singletons (P=0.62). ROP was detected in 60% of quadruplets versus 9.6% of twins and triplets; threshold disease was observed in 40% of quadruplets as compared to 4.2% of twins and triplets (P<0.03). However, considering the effect of BW and GA, logistic regression analysis revealed no statistically significant difference in the frequency and severity of ROP among subgroups of multiple-gestation pregnancies. Conclusion: There was no significant difference between multiple-birth neonates and matched singletons in terms of frequency and severity of ROP. Any apparent higher rate may be due to independent risk factors such as low birth weight and gestational age rather than multiple pregnancies per se. Screening for ROP in multiple gestation births may be conducted according to standard protocols applied for singletons.

The number of people with diabetes mellitus is increasing and cataracts are one of the most common causes of visual impairment in these subjects. Advances in cataract surgical techniques and instrumentation have generally improved the outcomes; however, surgery may not be safe and effective in certain individuals with pre-existing retinal pathology or limited visual potential. This review article aims to address different aspects surrounding cataracts in diabetic patients. In a computerized MEDLINE search, relevant studies were selected by two authors using the keywords “diabetes mellitus”, “cataract”, “diabetic retinopathy” and “diabetic maculopathy”.

Purpose: To report the histopathologic features of corneal involvement in a patient with xeroderma pigmentosum (XP).Case Report: A 19-year-old man with XP presented with bilateral corneal leukoma and decreased visual acuity predominatly in his right eye. Penetrating keratoplasty was performed in the right eye due to severe corneal opacity, vascularization and lipid deposition. The corneal button underwent histopathologic evaluation which disclosed chronic interstitial lipogranulomatous keratitis.Conclusion: To our knowledge, this is the first report of corneal involvement in xeroderma pigmentosum from Iran describing the histopathologic features in this rare condition.

Purpose: To present a case of autosomal dominant dystrophic epidermolysis bullosa with symblepharon formation due to eye rubbing.Case Report: A 10-year-old girl suffering from blistering and ulcerative lesions of the trunk and palms and dystrophic nails since childhood was referred to our clinic with a symblepharon connecting the medial portion of the right upper lid to the superonasal quadrant of the cornea. The central cornea in both eyes exhibited mild subepithelial opacification. She had history of eye rubbing due to foreign body sensation in the right eye, resulting in red eye and blister-like conjunctival lesions since three years ago. She had previously undergone surgical symblepharon removal leading to more severe recurrence of the condition.Conclusion: Dominant dystrophic epidermolysis bullosa may be accompanied by external ocular manifestations. Protection of the eye from minor trauma such as rubbing may help prevent ocular complications.