Posterior capsular opacification in pseudophakic eyes with a silicone or acrylic intraocular lens.

PURPOSE: To compare posterior capsular opacification in eyes with IOL of two different materials--silicone or acrylic. METHODS: Eighty consecutive eyes undergoing cataract surgery were prospectively randomized in two groups, 40 eyes receiving a silicone (Sl--30NB) and 40 eyes an acrylic (Acrysof MA60BM) intraocular lens (IOL). The same surgeon performed phacoemulsification and the intraocular lens (PHACO IOL) operation in all cases. Patients were re-examined on the first postoperative day, after one week, four months, and 1-2.4 years. Seven eyes were lost to late control. RESULTS: Clinically significant posterior capsular opacification (PCO) (including eyes with capsulotomy already performed) was equally common in both groups; 25% in the silicone group and 19% in the acrylic group (p=0.53). The posterior capsule remained clear in 61% of the silicone and 76% of the acrylic IOL eyes (p=0.18). In the whole study group, 29% of eyes with and 14% without concurrent ocular diseases had significant PCO (p=0.13). In the silicone IOL group, PCO was more common in eyes with concurrent ocular diseases (44%) than eyes without other diseases (10%) (p=0.049). Eyes with acrylic IOL showed no difference in significant PCO, with or without other diseases (18% and 20%, respectively). CONCLUSIONS: In a consecutive series of 80 cataract eyes central PCO was equally common in eyes receiving a silicone or an acrylic IOL. In the silicone IOL group, however, significant PCO was more common if there was concurrent ocular disease, while with the acrylic IOL concurrent ocular disease did not seem to increase the risk of PCO.

Topical anesthesia with or without propofol sedation versus retrobulbar/peribulbar anesthesia for cataract extraction: prospective randomized trial.

PURPOSE: To evaluate the feasibility of intravenous sedation in addition to topical anesthesia during cataract extraction. SETTING: Helsinki University Eye Hospital, Helsinki, Finland. METHODS: Three hundred seventeen eyes of 291 consecutive patients having cataract surgery were prospectively randomized to receive topical (oxybuprocaine 0.4%, n = 96), combined (topical anesthesia and propofol sedation, n = 107), or retrobulbar/peribulbar (prilocaine 1.5%, n = 114) anesthesia. The intraoperative conditions were judged by the surgeon. A numerical scale (0 to 10) was used to assess the degree of pain during surgery. Outcome measures were the number of complications and adverse events registered perioperatively and 1 week postoperatively as well as Snellen visual acuity. RESULTS: The success of posterior chamber intraocular lens (IOL) implantation through a self-sealing clear corneal incision was 97.9%, 96.3%, and 98.2% in the topical, combined, and retrobulbar/peribulbar groups, respectively. There was no difference among the groups in pain during surgery, frequency of complications, or outcome measures. One week postoperatively, visual acuity was 20/40 or better in 81.7%, 78.5%, and 77.5% of eyes in the topical, combined, and retrobulbar/peribulbar groups, respectively. The surgeon reported significantly fewer difficulties in the retrobulbar/peribulbar group (9.8%) than in the topical (26.0%) (P =.004) or combined (21.0%) (P =.036) groups. Additional sedative/analgesic medication given intraoperatively was required significantly more often in the topical (15.6%) than in the retrobulbar/peribulbar group (2.6%) (P =.002). Patients with bilateral surgery preferred combined anesthesia over retrobulbar/peribulbar anesthesia; however, there was no significant difference in patient acceptance among groups in patients having unilateral surgery. CONCLUSION: Intravenous propofol sedation added to topical anesthesia did not improve the operative conditions or surgical outcome. Retrobulbar/peribulbar anesthesia ensured the best surgical conditions. Patients in all anesthesia groups reported high satisfaction. However, patients having bilateral surgery seemed to prefer combined anesthesia over retrobulbar/peribulbar anesthesia.

Phacoemulsification and intraocular lens implantation in eyes with open-angle glaucoma.

PURPOSE: To study the effect of phacoemulsification and intraocular lens implantation (PHACO IOL) on intraocular pressure (IOP) and glaucoma medication in open-angle glaucoma (OAG) eyes. METHODS: 38 open-angle glaucoma (OAG) eyes with cataract underwent phacoemulsification and intraocular lens implantation (PHACO IOL) performed by one surgeon (RJU). None of the patients had prior intraocular surgery. Surgery was performed by scleral incision on 37% and by clear corneal incision on 63%. Patients were re-examined on the first postoperative day, after one week, 4 months, and in 29 cases 1-3.7 (mean 2.8) years after the operation. RESULTS: The mean preoperative IOP was 18.4+/-3.3 mmHg with a mean of 1.7 glaucoma medications. On the first postoperative day, the mean IOP rose to 28.2 +/- 12.5 mmHg. IOP > or = 30 mmHg occurred in 39.5% of the eyes. After one week, IOP had returned to the preoperative level. After 4 months, IOP had further decreased to 16.1 +/- 3.8 mmHg (p = 0.0027). After a mean follow-up of 1-3.7 (mean 2.8) years, the average postoperative IOP was 15.1 +/- 2.9 mmHg, being significantly (p = 0.001) lower than the preoperative IOP with 86% of the patients having a mean of 1.6 drugs on average. The type of incision (scleral vs. corneal) did not affect the postoperative IOP level. Using the criteria of Bigger and Becker (1971) the long-term IOP control after PHACO-IOL surgery was improved or unchanged in 86% and worse in 14% of the preoperatively well-controlled OAG eyes. CONCLUSIONS: In OAG eyes PHACO IOL is associated with a significant decrease in IOP with less medication up to 1-3.7 (mean 2.8) years.

Intraocular pressure after phacoemulsification and intraocular lens implantation in nonglaucomatous eyes with and without exfoliation.

PURPOSE: To evaluate intraocular pressure (IOP) after phacoemulsification and intraocular lens (IOL) implantation in nonglaucomatous eyes with and without exfoliation. SETTING: Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland. METHODS: One hundred ninety-six eyes that had phacoemulsification with IOL implantation were examined. Eyes with a history of intraocular disease or surgery that could affect IOP were excluded. The study comprised the remaining 160 eyes: 23 with exfoliation (EXF group) and 137 without exfoliation (non-EXF group). Follow-up data were available for 136 eyes. The same surgeon performed all surgeries. Patients were examined on the first postoperative day and after 1 week, 4 months, and 1.0 to 2.7 years. RESULTS: One day postoperatively, IOP rose in the EXF group from a mean preoperative level of 16.3 mm Hg +/- 2.7 (SD) to 21.0 +/- 8.5 mm Hg, a 28.4% increase (P =.0061). In the non-EXF group, mean IOP rose from 16.2 +/- 3.4 mm Hg to 20.5 +/- 5.7 mm Hg, a 29.9% increase (P =.001). In 4 eyes (17.4%) in the EXF group and 8 eyes (5.8%) in the non-EXF group, IOP increased to 30 mm Hg or higher at 1 day. After this, significant IOP decreases occurred in both the EXF and non-EXF group, respectively, as follows: 14.2 +/- 3.0 mm Hg (12.0% decrease from preoperative value; P =.001) and 15.0 +/- 2.9 mm Hg (5.9%; P =.001) 1 week postoperatively; 12.8 +/- 2.7 mm Hg (20.2%; P =.0002) and 13.8 +/- 2.7 mm Hg (13.2%; P =.001) after 4 months; and 12.3 +/- 2.6 mm Hg (23.2%; P =.0001) and 12.7 +/- 2.7 mm Hg (21.2%; P =.001) after 1.0 to 2.7 years. There was no significant difference between the 2 groups. CONCLUSION: After phacoemulsification with IOL implantation, IOP decreased significantly and remained lower than preoperatively in eyes with and without exfoliation. One day postoperatively, transient pressure peaks were more common in eyes with exfoliation. One eye without exfoliation developed glaucoma.

Evaluating cataract surgery gains by assessing patients' quality of life using the VF-7.

PURPOSE: To describe the development and performance of a questionnaire designed to measure functional impairment caused by cataract. SETTING: Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland. METHODS: The results of a visual-functioning index (VF-14) of 168 patients with first-eye cataract surgery were analyzed. Patients with significant comorbidity were excluded, leaving 142 patients for the final analysis. Snellen visual acuity measurements and complete preoperative and 4 month postoperative clinical status were performed by ophthalmologists. Outcome measures, including the VF-14, patient perception of trouble with vision, patient satisfaction with vision, and the cataract symptom score, were taken by nurses at the preoperative clinical examinations and at the 4 month postoperative visit. The Spearman rank correlation was used to determine which items of the VF-14 best correlated with a change in patient satisfaction. RESULTS: Seven items of the VF-14 that best correlated with patient satisfaction were selected for inclusion in a new 7-item index (the VF-7). Based on the Spearman rank correlation, the items from best to worst were nighttime driving; reading small print; watching television; seeing steps, stairs, or curbs; reading traffic, street, or store signs; cooking; and doing fine handwork. The correlation among changes in the VF-7 score and visual acuity in the operated eye was 0.17, while the correlation among changes in the VF-7 and patient satisfaction caused by cataract surgery was high (r = .56). CONCLUSION: The VF-7 was a strong predictor of change in patient satisfaction caused by cataract surgery.

Converting to topical anesthesia in cataract surgery.

PURPOSE: To evaluate the complications and difficulties encountered by surgeons converting from paraocular to topical anesthesia in cataract surgery and to evaluate patient pain and satisfaction with each procedure. SETTING: Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland. METHODS: Three hundred eyes of 245 consecutive patients were prospectively assigned by permuted block-restricted randomization to receive topical (bupivacaine 0.75%) (Group 1; n = 136) or paraocular (Group 2; n = 163) anesthesia. The intraoperative conditions were judged by the surgeon. A numerical scale (0 to 10) was used to assess the degree of pain during administration of anesthesia, during surgery, and 1 and 24 hours postoperatively. Outcome measures were the number of complications and adverse events registered perioperatively and 4 months postoperatively as well as Snellen visual acuity and surgically induced astigmatism (SIA) measured 1 week and 4 months after surgery. RESULTS: The success of posterior chamber intraocular lens (IOL) implantation through a self-sealing clear corneal incision was very high (99.3% and 96.9% in Groups 1 and 2, respectively). One case (0.7%) in the topical group required vitrectomy and implantation of an anterior chamber IOL. Anesthesia-related difficulties were reported in about 40% of patients in Group 1 and 4% in Group 2 (P < .001). Supplemental paraocular anesthesia was required in 4 cases (2.9%) in the topical group. Sedative/analgesic medication given perioperatively was required significantly more often in Group 1 (13.2%) than in Group 2 (2.4%) (P < .01). Significantly more pain during surgery (P < .001) and 1 hour after surgery (P < .001) was reported in the topical group. In Group 1 69.9% and in Group 2 93.3% reported no pain during surgery (P < .001). Chemosis (1.8%), subconjunctival hemorrhage (1.2%), and periorbital hematoma (1.2%) were seen only in the paraocular group. Perioperatively, no severe complications occurred in Group 1 and the number of adverse events was less than in Group 2. Postoperatively, 2 cases of endophthalmitis developed in the topical group and none in the paraocular group. There was no between-group difference in outcome measures; a visual acuity of 20/40 or better was found in 87.8% of eyes in Group 1 and 84.9% in Group 2 4 months postoperatively, and the percentages of eyes with SIAs within 1.0 diopter of preoperative values were similar (78.6% and 73.3%, respectively). Patient preference for topical anesthesia appeared to be higher than for paraocular anesthesia. CONCLUSION: Paraocular anesthesia gave better analgesia than topical, but topical anesthesia provided acceptable analgesia during surgery and showed that intraocular procedures can be performed without akinesia. The surgeon converting to topical anesthesia may expect slight difficulty in 40% of cases and more severe difficulty in 7%. Surgically related complications were similar with both methods.

Outcomes of small incision cataract surgery.

PURPOSE: To compare cataract surgery outcome measures 4 months postoperatively and determine their association with changes in the eye's functional state. SETTING: Department of Ophthalmology, Helsinki University Central Hospital, Finland. METHODS: This longitudinal study comprised 219 consecutive patients having first-eye or second-eye cataract surgery by one surgeon. In most patients, the technique consisted of small-incision cataract surgery with in-the-bag intraocular lens implantation. Patients were interviewed and clinical data obtained preoperatively and 4 months postoperatively. Adverse events occurring within 24 hours and 4 months postoperatively were compared with changes in global measures of vision. Surgical success in terms of surgically induced astigmatism (SIA) was measured at 4 months using vector analysis of the changes in astigmatism and defining the extent to which the surgical goal was achieved. The association between the surgical astigmatism goals and global measures of vision was analyzed. RESULTS: The percentage of patients showing improvement 4 months after first-eye cataract surgery varied by outcome measure: Snellen visual acuity (95.0%), VF-14 score (89.4%), satisfaction with vision (80.1%), self-reported trouble with vision (75.8%), and cataract symptoms (75.1%). Changes in Snellen acuity after second-eye cataract surgery were similar but VF-14 changes were significantly less than after first-eye surgery. Changes in global measures of vision were also better after first-eye surgery. The correlation between the change in VF-14 score and global measures of vision was stronger than between the change in Snellen acuity and the same general outcome measures. A good correlation was also seen between the changes in VF-14 scores and cataract symptoms. Mean SIA in all eyes was 0.2 diopter (D) +/- 0.7 (SD); 91.2% were within +/- 1.0 D of preoperative values. Failure to achieve surgical astigmatism goals was not associated with patients in whom global measures of vision did not improve, nor was there a correlation between adverse events occurring within 24 hours or 4 months postoperatively and global measures of vision. The only association was between ocular comorbidity or potential risk factors of phacoemulsification and adverse events seen within 24 hours and at 4 months. CONCLUSION: Estimates of the proportion of patients benefiting from cataract surgery varied with the outcome measure used to determine benefit. The change in the VF-14 score was a better measure than Snellen acuity of the benefit of cataract surgery.

Traumatic aphakia treated with an iris prosthesis/intraocular lens or epikeratophakia.

OBJECTIVE: We retrospectively analyzed the visual results and postoperative complications associated with severely traumatized eyes in which aphakia was corrected with epikeratophakia or a sutured iris prosthesis/intraocular lens (IOL). METHODS: Fourteen eyes (14 patients) with traumatic aphakia and severe anterior segment complications were corrected either with epikeratophakia or a sutured iris prosthesis/IOL. All eyes lacked lens capsule or iris support for an IOL. The surgical technique of implanting an iris prosthesis/IOL employed transcleral suturing in the ciliary sulcus combined with penetrating keratoplasty. RESULTS: In the eight eyes treated with epikeratophakia, four (50%) had spectacle-corrected visual acuity of 20/40 or better. Almost all of these eyes lost one or two Snellen lines of baseline spectacle-corrected visual acuity. Few complications occurred after epikeratophakia; none were severe. Of six eyes with penetrating keratoplasty and a sutured iris prosthesis/IOL or a sutured posterior chamber IOL, two (33%) achieved a visual acuity of 20/40 or better. In the IOL group, severe complications occurred, including posterior dislocation of the lens and secondary glaucoma. CONCLUSIONS: The surgical correction of aphakia in severely traumatized eyes requires specialized surgical techniques. Epikeratophakia is a low-risk operation that can be performed in eyes in which an IOL is contraindicated. The iris prosthesis/IOL technique results in good cosmetic results; however, due to complications, this technique should be used with caution.

Long-term follow-up of pediatric epikeratophakia.

BACKGROUND: Epikeratophakia is a potentially reversible corneal surgical procedure that can correct refractive errors in children who are aphakic and poor candidates for intraocular lens implantation. The correction of aphakia in the pediatric population poses specific problems because of associated amblyopia. METHODS: The clinical records of 61 consecutive patients (82 eyes) treated for pediatric aphakia by epikeratophakia were reviewed retrospectively with a follow-up of 3 to 5 years. For the purpose of analysis, the patients were divided into seven groups. RESULTS: The overall success rate for epikeratophakia was 92%, but with repeated surgery, the patient success rate was 93%. The average refractive error at 1 year was + 0.10 diopters (D). At 1 year, 68% of eyes had a refraction within 1 D of emmetropia. In these growing eyes, we documented an average myopic shift of -0.40 D during 4 years. A myopic shift occurred in 30.2% and a hyperopic shift in 9.4% of eyes. Spectacle-corrected visual acuity at 3 years showed 36% of eyes seeing 20/40 or better. Visual acuity results in different groups varied with the timing of epikeratophakia, density of amblyopia and parents' ability to maintain the patching schedule. The most encouraging results came from the treatment of monocular traumatic cataracts. In this group, 31% achieved visual acuities of 20/40 or better and 85% achieved 20/100 or better at final examination. Those with incomplete congenital cataracts also showed favorable results: 39% achieved 20/40 or better at final examination. CONCLUSIONS: Follow-up of 3 to 5 years demonstrated that epikeratophakia can correct refractive errors safely and successfully in aphakic children, either as a primary procedure, or as a secondary procedure after cataract extraction.

Photoastigmatic keratectomy for correction of astigmatism in corneal grafts.

BACKGROUND: The efficacy and safety of excimer laser photoastigmatic refractive keratectomy (PARK) for treatment of astigmatism after penetrating keratoplasty (PKP) was evaluated in this study. METHODS: A VisX 20/20 excimer laser was used to correct the regular astigmatic component of the grafts. The epithelium was removed manually in seven cases and in three patients with the PTK mode of the laser. The results were analyzed for uncorrected visual acuity (UCVA), best corrected acuity (BCVA), haze, and changes in the cylinder and axis. The vectorial change in astigmatism was measured using Alpins' method. RESULTS: Preoperative astigmatism ranged from 3.50 to 11.25 D (mean, 5.98 +/- 2.28) and the mean attempted correction of astigmatism was 6.28 +/- 1.56 D (range, 3.50-9.00 D). The induced reduction of net corneal astigmatism was 48.1%. The vector-corrected astigmatism, which was 6.40 +/- 3.49 D at 1 month postoperatively, was reduced at 12 months to 4.28 +/- 2.42 D. The Alpin Success Index varied in the range 0.06 to 1.0. Although the UCVA improved by > or = 2 lines in 60% of the eyes, the BCVA decreased in 40% of the eyes and three patients required a reoperation. CONCLUSION: Although PARK is relatively safe and effective in reducing post-PKP cylinder and improves UCVA, the frequently and surprisingly late-developing corneal haze often impairs the BCVA.

Use of collagen shields in cataract surgery.

A randomized, prospective, multicenter study evaluated the efficacy and safety of using collagen shields to deliver drugs after cataract surgery. Collagen shields saturated with an antibiotic and a steroid were placed in 90 eyes postoperatively. A control group of 93 eyes received the same drugs through a peribulbar/retrobulbar injection. One day after surgery, the shield group had significantly less corneal edema, conjunctival hemorrhaging, and postoperative pain and fewer corneal opacities. All symptoms except the conjunctival hemorrhaging disappeared by day seven. Our study suggests that using collagen shields for drug delivery after cataract surgery decreases tissue damage and increases patient comfort without adverse side effects.

Early rehabilitation after small incision cataract surgery.

BACKGROUND: The use of smaller cataract incision is thought to induce less astigmatism, resulting in a more stable refraction and more stable wound. METHODS: We have analyzed the early astigmatic changes and rehabilitation in 20 eyes of 16 patients operated with advanced phacoemulsification techniques. The patients operated with small-incision surgery (incision 4.0 mm) were compared to those with large-incision surgery (incision 7.5 mm). Keratometric values and visual acuity data were evaluated up to 6 months postoperatively. RESULTS: Less initial induced astigmatism was demonstrated at day 7 postoperatively with a 4.0-millimeter incision (0.1 +/- 0.53 D) compared with a 7.5-millimeter incision (1.90 +/- 1.97). Similar but not statistically significant changes were seen at days 1 and 30 postoperatively. Visual rehabilitation was also faster in the small-incision group and 70% of the eyes gave uncorrected visual acuity of 20/40 or better in this group as early as the first postoperative day. Only 11% of the eyes showed that uncorrected visual acuity after large-incision surgery at first postoperative day. CONCLUSION: The low amount of induced cylinder, rapid stabilization of the wound, and faster visual rehabilitation confirms the advantage of small-incision cataract surgery to large-incision surgery.

Irradiation cataract in children after bone marrow transplantation.

Chemotherapy and radiation produce a dose-dependent anti-leukemic effect. Combined chemoradiotherapy and bone marrow transplantation (BMT) were given in our clinic to treat children with acute leukemias. Total body irradiation of 10 Gy in a single dose was used. One long-term side effect of this treatment was the development of subcapsular cataract; this was seen in all nine long-term survivors of the 17 children with acute lymphoblastic (ALL) or acute myelogenous (AML) leukemia who were treated as described above. One year after marrow transplantation, all the eyes studied had visual acuity of 20/20 and an optically clear lens. Three years later, 60% of the eyes had visual acuity of less than 20/40 and all had posterior, subcapsular cataracts. The cataract in all cases was quite uniform, consisting of opacities in the posterior subcapsular region. Cataract formation was treatment-related and seemed to correlate only to the type of total body irradiation. We concluded that the cataracts seen in the present study were a late complication of allogeneic BMT and were specifically due to the single-dose total body irradiation.

Long-term evaluation of timolol.

Maintenance effect of the topical beta-blocker timolol on intraocular pressure (IOP) was investigated for a mean follow-up of 31.6 months in a group of 155 patients (275 eyes) with glaucoma or ocular hypertension. The mean IOP-value was calculated from 3 readings of the daytime IOP curve, and the mean eye pressure of the right and left eye in the respective individual was used. The medical therapy was carried out with our ranking order of drugs of choice: timolol, timolol combined with adjunctive drug therapy, laser trabeculoplasty and/or filtering surgery. Intraocular pressure was controlled with timolol alone in 98 of 155 patients (63.2%, Group 1). In 36 patients, timolol plus adjunctive medication was required to control IOP (23.2%, Group 2). Twenty-one (13.6%, Group 3) required either laser trabeculoplasty or filtering surgery in addition to timolol. Sufficient IOP-lowering effect was more frequently maintained in patients with ocular hypertension than those with glaucoma simplex or capsular glaucoma. Failures in timolol treatment occurred mostly within 6 months from the start of the therapy and correlated well with higher initial IOP. Transient adverse effects were observed in 11.2% of cases. In three cases (1.9%) local and systemic side effects were serious enough to require discontinuation of the drug therapy. One patient (0.7%) was a non-responder and was withdrawn from the study for that reason. Sixteen patients (10.3%) were lost to follow-up during the 4 year study.

Visual, refractive, and keratometric results of epikeratophakia in children. A two-year follow-up.

Fifty-two patients under the age of 16 years (68 eyes) received epikeratophakia grafts for the correction of aphakia. In 27 eyes, epikeratophakia was a primary procedure combined with lensectomy. Fifteen children underwent bilateral surgery. Overall, the success rate was 91%, and with repeated surgery it was 94%. The average change in refractive error was 15.9 diopters (D) and the average spectacle overcorrection was +0.3 D. Sixty-one percent (35/57) of the eyes were within 1 D of emmetropia and 97% (55/57) were within 3 D of emmetropia. Overall, the refraction was stable in the follow-up between six months and 1 1/2 years following surgery. However, a myopic shift of 2.0 D occurred between six months and 1 1/2 years in very young children following refractive surgery. The corneal curvature was measured only in older children and showed an average increase of 10.7 D. Visual acuity results in verbal patients were comparable to those in patients with contact lenses. The majority of smaller children demonstrated improvement in visual acuity with a combination of epikeratophakia and amblyopia therapy.

One-year follow-up of epikeratophakia for keratoconus.

We report 1-year follow-up findings on 42 of the first epikeratophakia procedures performed for keratoconus at the Helsinki University Central Hospital. Altogether 40 patients (42 eyes) received epikeratophakia grafts to flatten their cones. The age of the patients ranged between 19 and 44 years. The mean follow-up for these patients was 10.7 +/- 4.4 months, and in 12 patients follow-up extended to over 12 months. Overall, the success rate for the procedure was 93%, and with repeated surgery it was 97% for all patients; in all patients uncorrected visual acuity improved. Preoperatively 82% of the patients had uncorrected acuity worse than 20/400, while all patients followed for 1 year had uncorrected visual acuity better than 20/400. At 6 and 12 months postoperatively best corrected visual acuities were all returned to within one line of their preoperative best corrected acuity; in 83% acuities were 20/40 or better 12 months postoperatively. Four patients out of 12 followed for 1 year needed no postoperative overrefraction at all. The mean flattening by keratometry readings was 9.8 diopters (D) and the mean decrease in myopia in terms of spherical equivalent was 5.3 D. The degree of irregular astigmatism was measured in five cases using LSU topographical corneal shape analysis, and showed that the mean preoperative irregular astigmatism of 3.9 D was reduced to 1.3 D in the long-term analysis. One case report is presented to show in detail the topographical changes induced by epikeratophakia in keratoconus. The noninvasive nature of the epikeratophakia procedure makes it a safe and desirable option for the treatment of keratoconus.

Epikeratophakia for treatment of keratoconus.

Epikeratophakia has been applied for the correction of aphakia in children and adults as well as for the treatment of keratoconus to correct the refractive errors accompanied by these conditions. In this paper we present preliminary results of the outcome of ten consecutive keratoconus patients who were subjected to epikeratophakia. The patients suffered from advanced keratoconus without any major haziness in the optic area of the cornea, and they had become unable to tolerate contact lenses. Follow-up period varied form 1 to 4 months. Two minor complications were verified (one erosion and one partly detached lenticule) but these were managed and further healing was without problems. The keratometry values were markedly changed by the operation. The improval of the visual acuity after the operation was accompanied by the postoperative increase in the transparency of the lenticule. Epikeratophakia seems to be a safe and relatively simple method for the treatment of keratoconus.

Epikeratophakia in children.

In the past two years 29 patients (ages 9 months to 15 years) received 37 epikeratophakia grafts. 91.1 percent of the original surgeries were successful. The average change in refractive error was 16.7 diopters, and the average spectacle overcorrection was +0.2 diopters. We have obtained good visual results in our very young patients were follow-up is already over 1 year. We demonstrated also some improvement in visual acuity in older children especially those with traumatic or secondary cataracts. The study demonstrates that we can add an average of +17.1 diopters with an epikeratophakia graft and that the amount of correction obtained is remarkable predicted.

Stimulation of adenylate cyclase of ciliary processes in response to decreased inflow of aqueous humour.

Intravitreal injection of ouabain was used to induce unilateral hypotony and to study the relationship of adenylate cyclase (AC) and sodium-potassium activated adenosine triphosphatase (NaK-ATPase) both of which are involved in the production of aqueous humour. After preliminary experiments, days 3 and 5 were chosen as representative times when IOP was maximally reduced and stable following ouabain injection. NaK-ATPase and adenylate cyclase activities were measured biochemically in the same homogenates of isolated ciliary processes (CP). Biochemical measurements showed that 46% of NaK-ATPase activity was inhibited after 3 days, and about 78% of NaK-ATPase was inhibited 5 days after ouabain injection. At the beginning of NaK-ATPase inhibition there was a significant stimulation of adenylate cyclase activity of the CP. The highest activities were seen 2 and 3 days after ouabain injection. The suggestion is made that these 2 enzymes are interdependent.

Surface localization of 5'-nucleotidase on the mouse lymphocyte.

The optimal conditions for the cytochemical localization of 5'-nucleotidase (AMPase) in the mouse lymphocyte have been established. Quantitative monitoring of the effects of fixation and the components of the cytochemical medium showed that the cytochemistry can be performed under conditions that do not lead to loss of AMPase activity, and also under conditions where penetration of the substrate into the cell has occurred. The cytochemical reaction product was seen only on the surface of a proportion of splenic lymphocytes, regardless of the fixative used. Biochemical data confirmed that AMPase is an ectoenzyme and is the only protein in splenic lymphocytes capable of catalysing the hydrolysis of AMP. The activity of 5'-nucleotidase was studied also by harvesting cells either from thymus or spleen of A/ST or Cd-1 mouse strains. The enzymatic activity in splenic lymphocytes was more than six time higher than the activity of intact thymus cells. Cytochemically it was evident that within splenic lymphocytes there was a distinct population of lymphocytes with readily demonstrable AMPase activity, and another with no cytochemically demonstrable AMPase activity. It was concluded that murine lymphocytes vary in their activity of AMPase, and that the enzyme is exclusively confined to the cell surface.