Tear secretion following spherical and astigmatic excimer laser photorefractive keratectomy

PURPOSE

To evaluate the effect of spherical and astigmatic excimer laser photorefractive keratectomy (PRK and PARK, respectively) on tear secretion.

SETTING

The Vlemma Eye Center, Athens, Greece.

METHODS

Forty-eight eyes of 48 patients had PRK (28 eyes) or PARK (20 eyes) for the correction of myopia and combined myopic astigmatism. The fellow eye served as a control. The mean preoperative spherical equivalent was -3.96 diopters (D) +/- 1.00 (SD) in the PRK eyes (range -2.00 to -6.50 D) and -3.45 +/- 0.50 D in the PARK eyes (range -1.75 to -6.00 D). Attempted correction aimed at emmetropia. Schirmer I and II and tear film breakup time (BUT) tests were performed preoperatively and 1, 3, and 6 months postoperatively. All tests were correlated to the amount of attempted correction.

RESULTS

In the PRK group, the preoperative mean values were Schirmer I, 16.20 mm; Schirmer II, 12.73 mm; and BUT, 16.46 sec. At 1 month, they were 12.23 mm, 8.46 mm, and 13.33 sec, respectively; at 3 months, 13.86 mm, 10.64 mm, and 14.42 sec, respectively; at 6 months, 14.32 mm, 11.32 mm, and 15.36 sec, respectively. In the PARK group, the mean Schirmer I, II, and BUT values were preoperatively 18.52 mm, 14.86 mm, and 17.42 sec, respectively; at 1 month, 14.5 mm, 10.4 mm, and 14.36 sec, respectively; at 3 months, 15.36 mm, 11.81 mm, and 14.72 sec, respectively; and at 6 months, 16.5 mm, 12.15 mm, 16.5 sec, respectively. No correlation to the amount of attempted correction was found. Fellow-eye tests were not affected at any interval.

CONCLUSIONS

In the first 6 months after PRK and PARK, tear secretion test values decreased.

Clear lens extraction and intraocular lens implantation in Marfan's syndrome

Intracapsular clear crystalline lens extraction and intraocular lens (IOL) implantation were performed in 4 highly myopic eyes of 2 patients with Marfan's syndrome. One eye of each patient received an anterior chamber IOL and the other, a scleral-fixated posterior chamber IOL. The preoperative spherical equivalent ranged between -14.50 and -28.00 diopters (D) and axial length range, between 25.32 and 36.02 mm. The SRK II formula was used. Mean uncorrected visual acuity improved from counting fingers to 20/80. Postoperative spherical equivalent correction ranged from -0.75 to +2.75 D. One eye had vitreous loss that was managed by anterior vitrectomy. Modern surgery for cataract and management of its complications suggest that clear crystalline lens extraction and IOL implantation can be attempted in selected cases with Marfan's syndrome.

Crete, Greece glaucoma study

PURPOSE

To investigate the prevalence of primary open-angle glaucoma (POAG) in a randomized sample of the inhabitants of the island of Crete.

PATIENTS AND METHODS

In 18 different villages in all four prefectures of the island of Crete, patients were randomly selected from 1993 through 1998, and an in situ study was accomplished. The sampling fraction (covered by the 1991 census) in each village was approximately 5%. Patients were considered to have POAG when the morphologic aspect of a glaucomatous optic disc was present, and/or a nerve fiber layer defect and a visual field defect was present. The presence of Pseudoexfoliation syndrome (PEX) and pseudoexfoliative glaucoma (PEXG) was also investigated.

RESULTS

The prevalence of glaucoma in Crete was 2.80%. Of those diagnosed with POAG, 9.67% had an intraocular pressure (IOP) under 21 mm Hg, and 25.80% had PEX. The prevalence of simple ocular hypertension without glaucoma was found in 6.58% of the patients. The ratio of subjects with hypertensive glaucoma to those with simple ocular hypertension was 1:2.6.

CONCLUSION

The prevalence of POAG and exfoliation glaucoma appears to be quite high in Crete. Further research will be needed to set more accurate criteria for earlier diagnosis and to enable more efficient organization of the health care system.

Contact lens fitting difficulties following refractive surgery for high myopia

PURPOSE

To describe the clinical and optical problems encountered in contact lens fitting following refractive surgery for high myopia.

METHODS

Following refractive surgery for high myopia (greater than -10.00 D) we corrected residual refractive errors with contact lenses in the four eyes of two patients. The first patient had undergone bilateral laser in situ keratomileusis (LASIK),with two subsequent LASIK retreatments in the left eye. Ten months later she was fit with rigid gas permeable (RGP) lenses in both eyes. The second patient had undergone a clear lens extraction in the right eye and radial keratotomy followed by photorefractive keratectomy(PRK) in the left eye. She was fit with toric soft lenses six years postoperatively.

RESULTS

Final visual acuity obtained with contact lenses was 20/25-20/20 in all eyes. The first patient required significant minus lens power compensation. Furthermore, the RGP lens in the left eye was slightly decentered due to corneal irregularity induced by LASIK. The second patient had regular corneal surfaces and was successfully fit with daily wear toric soft lenses despite the 2.75 D of residual astigmatism in the left eye.

CONCLUSIONS

Following refractive surgery for high myopia a proportion of patients will remain undercorrected. In these patients the alterations in corneal architecture that ensue make contact lens fitting more challenging. Patients with regular astigmatism may be fitted successfully with toric soft lenses. Patients with corneal irregularities should be fit with RGP lenses.

Correlation of subepithelial haze and refractive regression 1 month after photorefractive keratectomy for myopia

PURPOSE

To relate myopic regression after photorefractive keratectomy (PRK) to subepithelial haze at the first postoperative month.

METHODS

One hundred nineteen eyes of 119 patients underwent excimer laser PRK for treatment of myopia up to -8.00 D. Eyes were examined at 1, 3, 6, 9, and 12 months after surgery. All eyes received fluorometholone 0.1% for the first 5 postoperative months in a tapered dose. Dexamethasone 0.1% qid for 1 month was prescribed to all eyes with a spherical equivalent refraction less than plano, followed by an augmented dose of fluorometholone 0.1%. Eyes with myopia greater than -0.75 D at 12 months, as well as those that had received dexamethasone at any postoperative interval--regardless of refractive outcome--were considered to be regressed. Eyes that regressed and those that did not regress were compared statistically (Chi-squared statistical criterion with Yate's correction) regarding haze grade.

RESULTS

Forty-seven percent (56 of 119) of eyes regressed. In 89.28% (50 of 56) of eyes, subepithelial haze grade was 1 to 2, and in 10.71% (6 of 56), subepithelial haze was graded 0 to 0.5 at 1 month. Fifty-three percent of eyes (63 of 119) did not regress and in all, subepithelial haze was graded 0 to 0.5 at the first month. The correlation between regression and haze grade 1 or more at the first postoperative month was statistically significant (P<.001).

CONCLUSION

Mild to marked subepithelial haze (grade 1 to 2) at the first postoperative month after PRK for myopia is strongly related to regression of initial refractive effect and increasing myopia.

Photorefractive keratectomy with a small spot laser and tracker

BACKGROUND

The Autonomous Technologies LADARVision excimer laser system utilizes an eye tracking mechanism and a small spot for photorefractive keratectomy.

METHODS

One hundred and two eyes of 102 patients were treated for -1.50 to -6.25 D of spherical myopia at the spectacle plane using a 6-mm diameter ablation zone. One year follow-up was available for 93 eyes (91%).

RESULTS

Uncorrected visual acuity for eyes treated for distance vision was 20/40 or better in 99% (n = 90), and 20/20 or better in 70% (n = 64) of eyes at 12 months. Spectacle-corrected visual acuity was 20/25 or better in all 92 eyes reported; no eye lost more than 2 lines of spectacle-corrected visual acuity, and only 1 eye (1.0%) experienced a loss of 2 lines (20/12.5 to 20/20) at 1 year. The refractive result was within +/- 0.50 D of the desired correction in 75% (n = 70), and within +/- 1.00 D in 93% (n = 86) of eyes at 12 months. Refractive stability was achieved between 3 and 6 months. Corneal haze was graded as trace or less in 100% of the 93 eyes. No significant reductions were noted in contrast sensitivity or endothelial cell density.

CONCLUSIONS

Patients treated with the Autonomous Technologies LADARVision excimer laser system for -1.50 to -6.25 D of spherical myopia with 1 year follow-up had uncorrected visual acuity of 20/20 or better in 70%, no significant loss of spectacle-corrected visual acuity, no reduction of endothelial cell density or contrast sensitivity, and low levels of corneal haze.

Seven years experience with LASIK for myopia

PURPOSE

This paper presents the results of the last seven years with LASIK for the treatment of myopia.

METHODS

4170 eyes of 3163 patients with a mean preoperative spherical equivalent--9.66 diopters were submitted to LASIK. The eyes were divided in three groups according to the preoperative refraction: Group A (-5 to 10D), group B (-10 to 16D) and group C (over -16 D).

RESULTS

At one year the percentage of eyes within +/- 1D of emmetropia was the following: group A: 84.4%, group B: 70.8%, and group C: 42.8%.

CONCLUSIONS

The method is safe, effective, and predictable especially in the range of myopia between -5 and -15 D of myopia. Predictability could be further improved by secondary procedures.

Corneal epithelial wound healing after excimer laser photorefractive and photoastigmatic keratectomy (PRK and PARK)

PURPOSE

This study compared the duration of corneal reepithelialization between photorefractive (PRK) and photoastigmatic (PARK) keratectomy and evaluated the possible correlation of the epithelial healing rate with clinical parameters as well as the refractive outcome.

METHODS

The duration until complete reepithelialization was examined in 33 eyes of 33 patients (14 men), not suffering from any known disease, who underwent PRK or PARK surgery. In all cases, a +0.5 diopters (D) therapeutic contact lens (Acuvue Vistakon) was used postoperatively. Clinical parameters such as age, sex, preoperative spherical equivalent, attempted correction, corneal curvature, and surgical plan were recorded in the patient file. All patients received standard medication and were followed up for 12 months postoperatively. Results were statistically analyzed by using the package SPSS 6.0.

RESULTS

The duration of reepithelialization was significantly correlated to age and was longer in PARK than in PRK cases and in eyes with an average K reading >43.5D. A shorter reepithelialization period correlated to myopic regression, 1 month postoperatively, but the correlation was annulled thereafter.

CONCLUSION

The longer reepithelialization period in older patients and in PARK surgery could be attributed to the age-related decrease in the healing response and to differences in the profile of the ablation area, respectively. Epithelial healing was shorter in eyes with steeper K readings, perhaps because of better contact lens mobility. Understanding the role of factors involved in epithelial healing could allow better postoperative surveillance and treatment.

Microbiological Examination of Bandage Soft Contact Lenses Used in Laser Refractive Surgery

BACKGROUND

Disposable soft contact lenses are known to be colonized by bacteria and play a key role in bacterial keratitis pathogenesis. Such lenses, commonly used after laser refractive surgery procedures in which postoperative corneal infiltrations are sometimes observed, are potentially a substrate for bacterial inoculation. This study evaluates the extent of such a contamination.

METHODS

Sixty disposable lenses collected from 60 eyes of patients who underwent photorefractive keratectomy (PRK), photoastigmatic refractive keratectomy (PARK), or laser in situ keratomileusis (LASIK) for the treatment of myopia or hyperopia were collected under sterile conditions over 4 months and cultured in various media. Results were statistically analyzed and the correlation with clinical and epidemiological data was examined.

RESULTS

Eleven (18.3%) of the examined lenses were contaminated with Staphylococcus epidermidis. No other bacteria or fungi were found. Contamination was significantly more common among female patients (P = .036). Correlation with the other clinical or operative parameters examined was statistically insignificant.

CONCLUSIONS

Contamination was independent of the surgical procedure and females who were frequent users of eyelid cosmetics displayed higher contamination frequencies, suggesting that bacteria possibly originate from eyelid flora. The isolation of Staphylococcus epidermidis requires close postoperative surveillance, since it is a known cause of keratitis. Prophylactic postoperative treatment with tobramycin, gentamycin, or sulphonamides could be indicated.

Photorefractive Keratectomy in Eyes with Congenital Nystagmus

BACKGROUND

We report 2 eyes of 2 patients with nystagmus and myopia who underwent photorefractive keratectomy (PRK) to correct myopia.

METHODS

A 32-year old male patient with a baseline spectacle-corrected visual acuity of 20/40 had PRK with an Aesculap Meditec MEL 60 excimer laser with a suction ring system for correction of a spherical equivalent of -8.25 diopters (D). A 19-year old male patient with baseline spectacle-corrected visual acuity of 20/50 had PRK with an Autonomous Technologies T-PRK flying spot and tracking excimer laser to correct a spherical equivalent of -5.00 D.

RESULTS

Twenty-seven months after PRK, the operated eye of the 32-year old patient had an uncorrected visual acuity of 20/32 and a spectacle-corrected visual acuity of 20/25. Six months postoperatively, the operated eye of the 19-year old patient had uncorrected and spectacle-corrected visual acuity of 20/50.

CONCLUSION

Patients with nystagmus are eligible for PRK to correct their refractive error with these two laser systems.

Topical use of zinc desferrioxamine for corneal alkali injury in a rabbit model

PURPOSE

To evaluate the efficacy of topical zinc desferrioxamine in acute corneal alkali injury in rabbits.

METHODS

Twenty rabbits were anesthetized and a standardized alkali burn (1N NaOH) was performed in the center of the cornea (7.5-mm diameter). The animals were randomly divided into two groups and treated (double-masked) with topical zinc desferrioxamine, 220 microM, (group 1) or its vehicle (group 2). Drops were applied 7 times/day for 28 days. Topical gentamicin, 0.3%, was instilled twice a day. Animals were evaluated twice a week. At each examination (using the slit-lamp), the depth of corneal ulcer was graded as follows: 0, no ulcer; 1, tissue loss less than one third of corneal thickness; 2, one third to two thirds tissue loss; 3, more than two thirds tissue loss; 4, descemetocele; or 5, perforation. Ulceration area, vascularization, and epithelial defects also were measured.

RESULTS

During the study period, the grading of mean corneal ulcerations in group 1 ranged from 0.2 to 1.00, whereas in group 2, it ranged from 1.4 to 2.7. The mean grade and area of ulceration in group 2 were greater than those in group 1 (p < 0.05).

CONCLUSION

Topical zinc desferrioxamine may be an adjunctive treatment in protecting the cornea against induced alkali injury.

Clear Lensectomy and Intraocular Lens Implantation for Hyperopia from +7 to +14 Diopters

BACKGROUND

Our results of clear lens extraction and intraocular lens implantation to correct hyperopia from +6.75 to +13.75 D are presented, as well as evaluation of two intraocular lens calculation formulae.

METHODS

Clear lens extraction and posterior chamber intraocular lens implantation was performed in 35 normally sighted eyes of 21 patients with a mean baseline hyperopic spherical equivalent refraction of +9.19 +/- 0.34 D (range +6.75 to +13.75 D). The refractive goal was -1.50 D, using the SRK II formula in 17 eyes and the SRK-T formula in 18 eyes. Follow-up was up to 5 years.

RESULTS

Mean uncorrected visual acuity after surgery was 0.8 (range 0.5 to 1.0). Stability of refraction was noted from the second month after surgery. No eyes lost any lines of spectacle-corrected visual acuity. Using the SRK II formula, 100% of eyes were within +/-1.00 D of emmetropia and with the SRK-T formula, 83.3% for a combined 91.4% of eyes within +/-1.00 D of emmetropia. One eye required intraocular lens exchange and another eye required photorefractive keratectomy for myopia. Both procedures were necessitated by an intraocular lens miscalculation of more than +/-2.00 D. Nineteen eyes (54.2%) developed posterior capsular opacification and were treated with Nd:YAG laser capsulotomy.

CONCLUSION

Clear lens extraction is a safe, effective, and predictable procedure for the treatment of hyperopia from +6.75 to +13.75 D. The SRK II formula proved slightly superior to the SRK-T in intraocular lens calculation when using the "-1.50 D rule."

Laser in situ keratomileusis to treat myopia: early experience

PURPOSE

To present our early experience in methodology and results of laser in situ keratomileusis (LASIK) in treating moderate and high myopia.

SETTING

Vardinoyannion Eye Institute of Crete and the Cornea and Refractive Surgery Service, Department of Ophthalmology, Heraklion University Hospital, Crete, Greece.

METHODS

Forty-three moderately to highly myopic eyes has LASIK. Follow-up was between 12 and 24 months. The Draeger's rotor microkeratome was used to create a 150 microns thick 8.5 x 9.5 mm corneal flap, and the stromal bed was ablated for the myopic correction using the Munnerlynn photorefractive keratectomy algorithm. The preoperative spherical equivalent ranged from -8.50 to -25.87 diopters (D). Attempted correction ranged from 8.00 to 16.00 D. Four eyes developed complications (i.e., anterior chamber perforation and keratoconus, intrastromal epithelial cells, macular lacquer cracks, and transient endothelial decompensation) and were excluded from the study. The remaining 39 eyes were retrospectively divided into two groups--A (21 eyes) and B (18 eyes)--according to the preoperative spherical equivalent (higher or lower than -14.00 D, respectively).

RESULTS

Refraction and corneal topography stabilized between 4 and 12 weeks postoperatively. Best spectacle-corrected visual acuity was within one Snellen line in all eyes. At 24 months, 19 eyes (79.2%) were within 2.00 D of intended correction. Attempted correction (12.20 D +/- 2.30 [SD]) was very close to mean achieved correction at 12 and 24 months (11.60 +/- 2.65 D). Mean postoperative astigmatism at 24 months (1.41 +/- 0.87 D; range 0 to 3.50 D) was close to the mean preoperative value (1.52 +/- 1.08 D; range 0 to 4.00 D). An average 2.43% endothelial cell loss was observed at 24 months.

CONCLUSION

With limitations, LASIK could be considered as a treatment for moderate and high myopia.

Excimer Laser Phototherapeutic Keratectomy for Corneal Opacities and Recurrent Erosion

BACKGROUND

Phototherapeutic keratectomy (PTK) has been used to treat superficial corneal opacities, as well as the recurrent corneal erosion syndrome.

METHODS

We performed PTK 6 eyes of 6 patients to treat corneal opacities, and in one eye of another patient to treat recurrent corneal erosion syndrome. Opacities were caused by a healed corneal ulcer, herpetic keratitis, band keratopathy, corneal burn, corneal dystrophy, and an excised pterygium. The follow-up period ranged from 2 to 6 months.

RESULTS

Corneal clarity improved to variable degrees in all eyes with corneal opacities. There was no recurrence in the Recurrent Corneal Erosion Syndrome. A hyperopic shift was observed in 2 eyes.

CONCLUSIONS

PTK appears to be an effective alternative to penetrating keratoplasty in patients with selected anterior stromal opacities can treat the Recurrent Corneal Erosion Syndrome.

Arcuate Transverse Keratotomy With a Mechanical Arcutome Based on Videokeratography

Corneal topographic hardware was used to develop software analysis for configuration and localization of relaxing astigmatic arcuate incisions. The software is based on the assessment of the results of corneal topographic measurements, performed by the EyeSys Corneal Analysis System. Data assessment includes: A) plotting the dioptric power curves along the circular zones that may be considered appropriate for the placement of arcuate cuts; B) determination of the astigmatic axes position in each selected arc; and C) finding the position of points with the mean dioptric power value between the neighboring astigmatic axes which determine the proposed placement of the arcuate incisions. The new instrument developed for arcuate astigmatic keratotomy includes the algorithm for incision(s) disposition, the software, and the arcutome.

Photorefractive Keratectomy With a Transition Zone for Myopia from -7 to -14 Diopters

PURPOSE

To study transition zone excimer laser photorefractive keratectomy (PRK) in moderate and high myopia defined as a spherical equivalent of -7.00 diopters (D) or more. The follow-up period was 18 months.

METHODS

Forty eyes of 40 patients with myopia of 7.00 to -13.50 D (mean +/- SD, -921 +/- 1.98) underwent transition zone (5.0 to 7.0 mm transition zone) PRK using the Aesculap Meditec Mel 60 excimer laser. The mean attempted correction was 8.3 +/- 1.64 D (range: -6.50 to -12.00 D).

RESULTS

At 18 months, 83% achieved an unaided visual acuity of 20/50 or better and HOW 12% 20/25 or better. Eighty-eight percent were within +/-2 D of emmetropia. the mean spherical equivalent was -1.1 D (+3.00 to -9.00 D).

CONCLUSIONS

Transition zone PRK is useful in moderate to high myopia. Regression, as well as overcorrection are issues for further investigation.

Excimer laser in situ keratomileusis and photorefractive keratectomy for correction of high myopia

BACKGROUND

The purpose of this research was to study the visual outcome of excimer laser photorefractive keratectomy and laser in situ keratomileusis (LASIK) for the correction of moderate and high myopia.

METHODS

Twenty partially-sighted eyes of 20 patients were divided into two groups, LASIK and photorefractive keratectomy. Ten eyes underwent LASIK and the other 10 photorefractive keratectomy. Follow up was at 1, 3, 6, and 12 months. The LASIK technique included a nasally based, 150 microns thick, 8.0 x 9.0 mm diameter, truncated, disc-shaped corneal flap created with a microkeratome; and the ablation of the stroma with a 193-nanometer ArF excimer laser. The flap was returned to its original position and held in place by apposition. The photorefractive keratectomy technique included mechanical removal of the epithelium and ablation of the stroma with a 193-nanometer ArF excimer laser.

RESULTS

LASIK series: One eye had a ruptured globe during the second postoperative month and was excluded from the study. The preoperative spherical equivalent refraction ranged from -10.62 to -25.87 diopters (D). The attempted correction ranged from -8.00 to -16.00 D. Postoperative refraction and corneal topography stabilized between 4 and 12 weeks. Spectacle-corrected visual acuity was within 1 Snellen line of preoperative in all eyes. The refraction in six eyes (66.6%) was within +/- 1.00 D of the intended correction, and in eight eyes was within +/- 2.00 D (88.8%) at 12 months. The mean attempted correction (11.40 +/- 2.60 D) was close to the mean achieved correction at 12 months (11.96 +/- 3.10 D). The mean postoperative refractive astigmatism (1.50 +/- 0.97; range, 0.25 to 3.50 D) was close to the preoperative astigmatism (1.70 +/- 1.15; range, 0 to 3.75 D). Endothelial cell density at 12 months showed an average 8.67% of cell loss. All eyes showed a clear interface. Photorefractive keratectomy series: The preoperative spherical equivalent refraction ranged from -10.75 to -23.12 D. The attempted correction ranged from -8.80 to -17.60 D. Postoperative refraction showed regression throughout the follow-up period, and corneal topography did not stabilize. Spectacle-corrected visual acuity was within 1 Snellen line in eight eyes. Two eyes lost 2 and 3 Snellen lines. One eye was within +/- 1.00 D, and three eyes (30%) were within +/- 2.00 D of the intended correction at 12 months. The achieved correction mean (7.17 +/- 5.29 D) was 61% of the attempted mean (11.72 +/- 2.81 D) at 12 months. The postoperative refractive astigmatism (1.80 +/- 0.95; range, 0.50 to 4.00 D) was very close to the preoperative (1.90 +/- 1.33; range, 0 to 5.00 D). Endothelial cell density showed an average of 10.56% cell loss at 12 months. The mean haze at 12 months was 1.2 (0 to 4 scale).

CONCLUSION

LASIK, although more complicated because of the use of a microkeratome, was more effective than photorefractive keratectomy in higher myopes. LASIK created less corneal haze. The refraction was more stable with LASIK in the correction of high myopia. Its predictability was three times that of PRK.

Rotating brush for fast removal of corneal epithelium

BACKGROUND

A simple new device is proposed for safe and very fast epithelial removal of the cornea. This is a rotating plastic brush that removes the corneal epithelium within a few seconds under irrigation, without causing any mechanical damage to the stromal surface.

METHODS

Comparative SEM and TEM studies on rabbit corneas were carried out following epithelial removal by rotating brush and by a Beaver knife blade. Epithelial removal time and reepithelialization time after photorefractive keratectomy were evaluated in a series of 40 human sighted eyes treated with the brush.

RESULTS

The rotating brush-abraded surface was smoother compared to the blade-abraded one. Additionally, the brush provoked no damage to the basal lamina of the rabbit corneal epithelium. In human photorefractive keratectomy, the mean time needed for removal of the corneal epithelium by the rotating brush was only 3 sec (range, 2-5 sec). Reepithelialization time following photorefractive keratectomy did not exceed 3 days.

CONCLUSION

Experimental and preliminary clinical studies suggest that the new rotating plastic brush is a safe and fast method for removing the corneal epithelium.

Clear lens extraction and intraocular lens implantation in normally sighted hyperopic eyes

BACKGROUND

Currently used corneal refractive procedures do not offer a perfect solution for high hyperopia. This article proposes clear lens extraction and intraocular lens (IOL) implantation for the correction of high hyperopia.

METHODS

Extracapsular clear lens extraction and posterior chamber IOL implantation was performed in 10 normally sighted eyes of five patients with a hyperopic spherical equivalent refraction between +7.88 and +9.75 D. The follow-up period was 18 months.

RESULTS

Mean uncorrected visual acuity improved from count fingers to 20/25. All eyes saw 20/30 or better without correction. Postoperative correction ranged from -0.37 to +0.50 diopters (mean, 0.01). The mean endothelial cell loss percentage at 18 months was 11.2% +/- 1.87% (range, 8% to 13%).

CONCLUSIONS

The excellent results of contemporary cataract surgery, the reduced morbidity, patient satisfaction, as well as accuracy and rapid stability of the refraction suggest that clear lens extraction and IOL implantation are useful refractive procedures for the correction of high hyperopia.

Achromobacter xylosoxidans keratitis following penetrating keratoplasty

BACKGROUND

Achromobacter xylosoxidans is a bacterium not previously reported in a corneal infection. We present a case of infectious keratitis caused by this organism, occurring 1 month following penetrating keratoplasty.

METHODS

Identification of the organism was accomplished by staining, culture, and sensitivity testing of the corneal scraping obtained from the involved area. The infection responded to subconjunctival ticarcillin, piperacillin eye drops, and I.V. azlocillin.

RESULTS

Complete healing with a resultant corneal opacity involving mostly the anterior and middle stroma was achieved 1 month later.

CONCLUSIONS

A. xylosoxidans should be considered as a potential pathogen in instances of early postkeratoplasty infectious keratitis.

Paraformaldehyde-induced keratitis after photorefractive keratectomy

We examined three patients who developed keratitis after myopic photorefractive keratectomy. All patients were treated on the same day and in all three cases paraformaldehyde tablets were used for disinfection of the excimer laser iris cone. All patients developed an intense postoperative corneal inflammation that resulted in corneal opacities. In the first patient, the opacities were central and persisted for at least 4 1/2 months postoperatively. He became more myopic than before the operation. His best spectacle-corrected visual acuity worsened by four Snellen lines. In the other two patients, the corneal opacities were paracentral and of less density. Six months postoperatively, these opacities were barely seen. In these two patients the postoperative best spectacle-corrected visual acuity remained unchanged or improved one Snellen line compared to the preoperative level. In all three patients, astigmatism increased postoperatively. These observations suggest that paraformaldehyde tablets are not safe for the disinfection of the excimer laser iris cone.

A corneal flap technique for laser in situ keratomileusis. Human studies

Using a modified microkeratome, nasally based central corneal flaps were created on six human blind eyes at a depth of 300 microns. The flaps were allowed to heal with a bandage soft contact lens, using neither sutures nor bioadhesives. The optical quality of the corneas was evaluated with biomicroscopic examination, computer-assisted topography, and optical pachometry during a 3-month follow-up period. The maintenance of transparency and lack of distortion of the corneal surface 3 months after surgery support the concept that the flap technique may be useful in laser in situ keratomileusis.