Choun-Ki Joo

Capsular opening contraction after continuous curvilinear capsulorhexis and intraocular lens implantation

Purpose: To evaluate the progressive constriction of the anterior capsule opening that can occur after continuous curvilinear capsulorhexis (CCC). Setting: Kangnam St. Mary’s Hospital, Seoul, Korea. Methods: Changes in the anterior capsule opening after CCC were evaluated in 166 pseudophakic eyes at 1 week and 1 and 3 months postoperatively. The capsular opening diameter was measured with an image analysis system. Results: The capsular opening diameter was reduced by an average of 13.87% 3 months after CCC. There was more dense opacity in the anterior than in the posterior capsule. Lens epithelial cells (LECs) were the main cause of capsule contraction; sex, age, intraocular lens haptic length and haptic material, and CCC size did not have a statistically significant effect on capsule shrinkage (P > .05). Three months after surgery, most eyes with an initial capsular opening diameter of less than 5.5 mm had an opening diameter smaller than 5.0 mm. In most eyes with an initial capsular opening larger than 5.5 mm, the opening remained larger than 5.0 mm. Conclusion: Our results suggest that the ideal CCC size is 5.5 to 6.0 mm or larger and that LEC removal is necessary to preserve the pupillary zone and thus prevent progressive capsular opening shrinkage.

Effect of a capsular tension ring on intraocular lens decentration and tilting after cataract surgery

Purpose: To evaluate the effect of a capsular tension ring (CTR) on the tilting and decentration of intraocular lenses (IOLs) after cataract surgery. Setting: Department of Ophthalmology, Ilsan Paik Hospital, Inje University, Kyunggyi‐do, Korea. Methods: Cataract surgery was performed in both eyes of 20 patients ranging in age from 57 to 75 years. The 40 eyes were divided into 2 groups based on whether a CTR (Lucid Korea) was implanted. Each patient received a CTR in 1 eye only. All IOLs (AcrySof® MA60BM, Alcon) were implanted in the capsular bag after a continuous curvilinear capsulorhexis smaller than the IOL optic was created and phacoemulsification performed. The extent of IOL tilting and decentration was measured with the EAS‐1000 anterior eye segment analysis system 7, 30, and 60 days after surgery. Results: The extent of IOL decentration was statistically significantly less in eyes with both an IOL and CTR than in those with an IOL only. The mean decentration in the CTR‐IOL group was 0.38 mm ± 0.16 (SD) at 7 days, 0.43 ± 0.15 mm at 30 days, and 0.42 ± 0.17 mm at 60 days. The mean values in the IOL‐only group were 0.49 ± 0.11 mm, 0.53 ± 0.14 mm, and 0.57 ± 0.16 mm, respectively. The amount of IOL tilting was also significantly less in the CTR‐IOL group. The mean tilting in the CTR‐IOL group was 2.22 ± 0.46 degrees at 7 days, 2.36 ± 0.50 degrees at 30 days, and 2.47 ± 0.40 degrees at 60 days. The mean values in the IOL‐only group were 3.14 ± 0.65 degrees, 2.91 ± 0.67 degrees, and 3.06 ± 0.56 degrees, respectively. Conclusion: These results indicate that the CTR reduces undesirable postsurgical IOL movement for at least 60 days.

Corneal perforation during laser in situ keratomileusis

Two cases of corneal perforation that occurred during laser ablation but not during flap formation in laser in situ keratomileusis (LASIK) are reported. In the first case, no problem in flap formation occurred, and stromal bed thickness was assumed to be about 239 microns after laser application. However, a stromal bed perforation was found when 608 pulses were applied (theoretical ablation depth was 140 microns). Excessive dehydration due to prolonged exposure to the operating microscope light may change the ablation rate and cause corneal perforation. In the second case, LASIK retreatment was performed using the original flap for correction of regressed myopia (-4.0 diopters). Although the stromal bed thickness was assumed to be about 175 microns after the laser application, a stromal bed perforation was found when 151 pulses were applied (theoretical ablation depth was 37 microns). Unexpected corneal ectasia after the first LASIK treatment may cause a corneal perforation in LASIK retreatment. In conclusion, excessive dehydration of the cornea should be avoided, and careful examination of the corneal shape is necessary to prevent corneal perforation during laser ablation in LASIK.

Phacoemulsification with a bevel-down phaco tip: Phaco-drill

Abstract We present a technique for in situ lens nucleus emulsification using low phaco power and high vacuum, a continuous curvilinear capsulorhexis, and hydrodelineation. Emulsification is done with the phaco tip slanted down 30 or 45 degrees. Cutting and aspiration do not cause an undesirable energy loss. This technique can be combined with the nuclear chopping or divide and conquer methods because of its ability to drill and hold the nucleus. Posterior capsular rupture is prevented because the separated epinucleus acts as a barrier between the nucleus and the cortex. The low power used minimizes the energy transfer to the corneal endothelium. This technique is particularly useful in eyes with brunescent cataract.

Effect of Flap Removal in Myopic Epi-LASIK Surgery on Visual Rehabilitation and Postoperative Pain: A Prospective Intraindividual Study

Purpose: A prospective intraindividual study to evaluate the effect of flap removal in myopic epi-LASIK surgery on visual rehabilitation and postoperative pain. Methods: Ninety eyes of 45 patients were treated for myopia with epi-LASIK. In each patient, the epithelial flap was repositioned in one eye after epi-LASIK (group 1) while the flap was removed in the other (group 2). Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), spherical equivalent (SE) refraction, postoperative pain and corneal haze were examined for 6 months after surgery in both groups. Results: Group 2 had a better UCVA at 4 days and BCVA at 1 week after surgery (p = 0.001, p = 0.043) than group 1. No significant differences were observed between the two groups in terms of UCVA, BCVA, or SE refraction at 1 week and 1, 2 and 6 months. Postoperative pain scores were similar for both groups. In group 2, severe pain (pain level ≧6) was relatively less than in group 1 at 2 h and 12 h after surgery. Corneal haze levels in both groups were not different. Conclusions: Epi-LASIK surgery with flap removal was found to significantly promote re-epithelialization and visual recovery during the early postoperative period. It was also found to be more predictable and less painful than epi-LASIK surgery.

Comparative immunological study of penetrating and anterior lamellar keratoplasty in a murine model

&NA; In lamellar keratoplasty, the diseased part of a cornea is replaced while the healthy tissue remains lamellar keratoplasty has the advantage of better graft survival compared to penetrating keratoplasty (PK). We compared the immunological responses to PK and anterior lamellar keratoplasty (ALK) in a murine model. PK or ALK was performed using C57BL/6 donor grafts and BALB/c recipients, and graft opacity was assessed to evaluate graft rejection up to 8 weeks. We evaluated the immunological responses in both groups, which were not clinically considered as graft failure on postoperative day 21. PK mice showed reduced clinical graft survival compared to ALK mice. The mRNA expression of inflammatory mediators, such as IL‐1&bgr;, IFN‐&ggr;, and granzyme B, in grafted corneas of PK mice, was significantly increased compared to the levels in ALK mice at postoperative day 21. PK led to a higher delayed‐type hypersensitivity response and IFN‐&ggr; secretion in an in vitro T cell assay from draining lymph nodes (LNs), as compared to ALK. Furthermore, PK showed increased angiogenesis and lymphangiogenesis in grafted corneas compared to ALK and led to greater infiltration of CD3+ T cells into grafted corneas and increased frequencies of mature antigen presenting cells (APC; MHC‐IIhighCD11c + cells) and IL‐12 + dendritic cells (DCs) in the draining LNs of transplanted mice. In conclusion, PK results in increased graft rejection compared to ALK through relatively increased neovascularization and lymphangiogenesis, which can induce infiltration of pathologic T cells and mature APC migration into grafted corneas and draining LNs. HighlightsAnterior lamellar keratoplasty (ALK) shows better graft survival compared to penetrating keratoplasty (PK) in murine model.PK leads to relatively higher delayed type hypersensitivity response.PK induces neovascularization and lymphangiogenesis more than ALK.