Phacoemulsification Using Microhook Iris Retractor for the Management of Ectopia Lentis in Marfan Syndrome

PURPOSE: We evaluated the clinical results of phacoemulsifacation using microhook iris retractor for the management of ectopia lentis in Marfan syndrome. METHODS: Seventeen eyes of 9 patients with Marfan syndrome were included. All the patients had undergone phacoemulsifacation with microhook iris retractor capsule stabilization between May 1997 and January 2000. RESULTS: Mean patient age was 11.6 +/-8.2 years old. Superior nasal(38%) and superior temporal(38%) were the most common direction of lens dislocation. Fifteen eyes demonstrated improvement in best corrected visual acuity by 2 lines or more following average follow-up period of 22.9 +/-9.2 months. As postoperative complications retinal detachment developed in 3 eyes. CONCLUSIONS: Phacoemulsifacation using microhook iris retractor for capsule stabilization appears to be a good technique for the management of ectopia lentis in Marfan syndrome.

Morphometric Study of Relationship between Plane of Inferior Oblique Muscle and Adjacent Globe Structure

There are no known data of recession point of inferior oblique muscle (IO) in Korean.The purpose of this study was to determine the accurate reinsertion point of IO and compare the previous data with ours.Thirty-one Korean cadaver orbits were dissected to expose the full length of extraocular muscles and sclera, and then we measured the length from the recession point of IO to lateral edge of insertion of inferior rectus muscle (IR)and to inferior edge of insertion of lateral rectus muscle (LR).Eight mm recession point of IO was measured 6.9 +/-0.6 mm posteriorly along the inferior border of LR from inferior edge of LR insertion, and 4.6 +/-1.5 mm inferiorly.For 10 mm recession, it was 5.6 +/-1.3 mm posteriorly and 6.6 +/-2.0 mm inferiorly.For 12 mm recession, it was measured 4.7 +/-0.7 mm posteriorly and 8.4 +/- 1.5 mm inferiorly.And for 14 mm recession, it was 3.7 +/-1.7 mm posteriorly and 9.5 +/-2.0 mm inferiorly. Eight mm recession point of IO was measured 3.5 +/-0.6 mm posteriorly along the lateral border of IR from the lateral edge of IR insertion, and 6.5 +/-0 .8 mm laterally.For 10 mm recession, it was 2.9 +/-1.0 mm posteriorly and 3.6 +/- 1.0 mm laterally.For 12 mm recession, it was measured 3.3 +/-0.6 mm posteriorly and 2.3 +/-0.6 mm laterally.For 14 mm recession, it was 3.0 +/-1.5 mm posteriorly and 0.5 +/-0.9 mm laterally.The cord length on a straight line from 14 mm recession point of IO to the scleral exit site of the inferior temporal vortex vein was 6.6 +/-1.4 mm (range 4~9 mm).The distance from IO recession points to IR insertion site and to LR insertion site were compared in ten paired eyes, and the difference was not statistically significant (p>0.05).We made anatomical studies to evaluate the proper placement of scleral reinsertion site of IO in Korean.

Clinical Results after Surgical Treatment in Congenital Cataract

There are many unknown factors in the surgical treatment of congenital cataract such as time of surgery, surgical problems, and aphakic visual correction. Recently, the advancement of microsurgical technique and visual rehabilitation have reduced the rate of postoperative complications and visual losses. We have studied 81 eyes of 55 patients who had recieved cataract surgery from January 1994 to January 1998 at the department of ophthalmology, Yonsei University College of Medicine. These eyes have been categorized by age into three groups : Group l (0~1 year), Group ll (2~5 years), and Group lll(6~10 years). Cataract extraction was done in all eyes and posterior chamber intraocular lens implantation was performed in groups ll and lllfor aphakic visual correction and the followings were investigated : preoperative vision; surgical method; postoperative vision; refractive error;and complications. Improvements in surgical procedures such as lens aspiration, posterior continuous circular capsulorhexis, anterior vitrectomy, intraocular lens implantation, and intraocular lens capture (Group ll) have brought better visual outcomes in groups II and III as well as decreased incidence of after-cataract. Thus, intraocular lens implantation in congenital cataract of 1year and older should actively be considered.

Clinical Evaluation of AMO Phacoflex SI-30NB in the Aspect of A-constant

We inspected reliability of A-constant of AMO SI-30NB by comparing target diopter and actual postoperative refractive status. Group 1 comprised 191 eyes which were implanted AMO PhacoFlex SI-30NB with corneal incision. Group 2 comprised 45 eyes implanted Pharmacia 812C with scleral incisions. Group 3 comprised 17 eyes implanted AMO OgaciFlex SI-30NB with corneal incision. Refraction was performed on post operative day 1, day 5, day 14, 1 month, and 3 month. It revealed hyperopic shift of 0.31 to 0.40 diopter compared to the target diopters in both Group 1 and Group 3 and no statistical difference was found between two groups(p value>0.05). On the other hand, Group 2 were statistically significant(p value<0.01). We attempted mathematical modelling of this phenomenon and the cause of hyperopylene haptics, structural weakness of haptic-optic junction, and the structure of SI-30NB itself.

Corneal Astigmatism Change after Simultaneous Surgery for Cataract and Pterygium

It is known that surgically induced astigmatism can be reduced by incision along the steep axis. Also, high grade astigmatism can be induced by pterygium. We evaluated the amount of corneal astigmatism according to the severity of pterygium in cataract patients. We retrospetively analysed the change of astigmatism after simultaneous surgery for cataract and pterygium retrospectively. We divided patients into two groups, temporal incision group. We confirmed that astigmatism is induced by moderate to severe pterygium. The more severe the pterygium, the more the amount of astigmatism. The amount of astigmatism was reduced after surgery irrespective of the incision. Postoperative astigmatic change was stabilized earlier in the temporal incision group than in the superior incision group. We concluded thath simultaneous surgery for cataract and pterygium can be considered when the severity of the pterygium is moderate to severe. Incision location in those surgeries should be decided according to whether the previous astigmatism was with-the-rule or aganinst-the-rule and this can be assumed by the state of astigmatism of the healthy, fellow sys. If the assumption is not possible, temporal incision is more desirable in aspectes of stability and predictability of postoperative astigmatism.

The Potential Acuity Meter to Predict Postoperative Visual Acuity after Cataract Surgery

The potential acuity meter(PAM) has been reported to be a useful instrument for predicting postoperative visual acuity after cataract extraction surgery. Forty nine eyes were tested with PAM before surgery, and the best postopertive visual acuity was obtained. The PAM accurately predicted the postoperative visual acuity to within three lines in 90.0% of the cases. When the test is in error, the tendency is for the PAM to underestimate the final acuity rather than to overestimate. Especially under undilated pupil, in dense cataracts (<20/200),and,in posterior subcapsular and cortical cataracts, the PAM tends to underestimate further.