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PubMed1996

The one-year surgical outcome after prism adaptation for the management of acquired esotropia.

PURPOSE: To report the 1-year motor and sensory outcomes for patients with acquired comitant esotropia managed with preoperative prism adaptation. METHODS: Patients entered a multicenter randomized prospective evaluation of prism adaptation before strabismus surgery. Prism responders were randomized to surgery with the target angle based on either the entry angle or the adapted angle of esotropia. Three hundred five patients (92 percent of cohort) completed 1-year postoperative follow-up. RESULTS: The overall motor success rate for all patients in the study was 74 percent. Prism responders operated on for the adapted esotropic target angle had a satisfactory motor outcome more often than those operated on for the entry angle, 90 percent compared with 75 percent (P = 0.04). Significant predictors of a satisfactory motor outcome after surgery were prism adaptation, female sex, and hyperopia greater than or equal to +3.00 D. Prism responders operated on for the adapted angle showed fusion of the Worth 4-dot at substantially more often than did those operated on for the entry angle, 75 percent compared with 60 percent (P = 0.12). CONCLUSION: Prism adaptation significantly improves the 1-year motor outcome after esotropia surgery in prism responders. There is no increase in the number of overcorrections. These results confirm the value of allotting the extra time and potential expense needed for this technique.

Adaptation, Ocular↗
PubMed1997

Theoretic refractive changes after lens implantation in childhood.

OBJECTIVE: Children with aphakia tend to have decreasing hyperopia as they grow older. No large study of the long-term refractive changes in children with pseudophakia has been published, although myopic shifts of greater than 10 diopters (D) have been reported. The authors used the refractions of children with aphakia and long follow-up to calculate the theoretic long-term refractive effects of pseudophakia. DESIGN: The study design was a chart review of eyes that underwent cataract surgery before age 10 with documented refractions for more than 7 years. PARTICIPANTS: Ninety-three eyes were studied. INTERVENTION: The initial aphakic refractions of the study eyes were used to calculate the intraocular lens (IOL) powers that would have been required to give emmetropia at cataract removal. The aphakic refractions at last follow-up were used to calculate the final pseudophakic refractions, and these were compared with the predictions of a logarithmic model of myopic shift. RESULTS: The mean follow-up time was 11 years. The median calculated pseudophakic refraction at last follow-up was -6.6 D with a range of -36.3 to +2.9 D. Children who underwent surgery in the first 2 years of life had a substantially greater myopic shift than older children (P < 0.001) and a larger variance in this myopic shift (P < 0.001). The logarithmic model accurately predicted the final refraction within 3 D in 24% of eyes undergoing surgery before 2 years of age and in 77% of eyes undergoing surgery after this age. CONCLUSIONS: Pseudophakia in children is predicted to result in a large quantity of myopic shift, particularly in very young children. An IOL power chosen to leave a child initially hyperopic should lessen both the quantity of myopic shift and the extreme myopia that can result with growth. The surgeon who implants IOLs in young children must be prepared for a wide variation in long-term myopic shift.

Cataract Extraction↗
PubMed1997

Biometry and primary angle-closure glaucoma among Chinese, white, and black populations.

PURPOSE: Primary angle-closure glaucoma (PACG) is more prevalent among Chinese than whites. The authors tested the hypothesis that Chinese have shallower anterior chambers than do whites, a factor that may be related to PACG prevalence. METHODS: The authors compared anterior chamber depth, axial length, radius of corneal curvature, and refractive error among 531 Chinese, 170 whites, and 188 blacks older than 40 years of age using the same model of instruments and identical technique. RESULTS: Mean anterior chamber depth and axial length did not differ significantly for the three groups. Whites had a significantly higher prevalence of hyperopia > 2 diopters than did Chinese. Radius of corneal curvature was significantly smaller among Chinese than whites or blacks. CONCLUSIONS: These results suggest that Chinese do not differ on a population basis from other ethnic groups in many of the biometric risk factors known to be of importance for PACG. It will be necessary to identify other ocular biometric parameters to explain the excess burden of PACG among Chinese, which may improve the effectiveness of screening for this disease in all populations.

Adult↗
PubMed1998

Prevalence of myopia between 3 months and 5 1/2 years in preterm infants with and without retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

PURPOSE: The purpose of the study was to examine spherical equivalent refractive errors, especially myopia, at six ages between 3 months and 5 1/2 years post-term in preterm children with birth weights of less than 1251 g. DESIGN: A cohort study. PARTICIPANTS: There were a total of 827 participants in the multicenter study of cryotherapy for retinopathy of prematurity (ROP). Approximately one third of the eyes did not develop ROP, whereas two thirds developed mild-to-severe ROP. None of the eyes underwent cryotherapy. INTERVENTION: Refractive error was measured at 3 months, 1 year, and 5 1/2 years term due date at the five long-term follow-up centers. In most eyes, refractive error also was measured at 2, 3 1/2, and 4 1/2 years. MAIN OUTCOME MEASURE: Myopia was defined as 0.25 diopter (D) or greater with high myopia as 5 D or greater. RESULTS: The proportion of eyes with myopia in this preterm population was increased compared to published data on full-term children and was related to severity of both acute-phase and cicatricial-phase ROP. The percentage of eyes with myopia varied little across ages, ranging from 21.2% at 1 year to 15.7% at 4 1/2 years. The percentage of eyes with high myopia doubled from 1.8% to 3.9% between 3 months and 1 year and remained stable thereafter. The distribution of refractive errors in eyes with mild acute-phase ROP was similar to that of eyes with no ROP. In contrast, eyes with moderate or severe acute-phase ROP showed an increased prevalence of high myopia. The distribution of refractive errors changed between 3 months and 1 year with little change after 1 year. This pattern of refractive development differs from that of full-term infants. Birth weight, severity of ROP, and degree of myopia at 3 months predicted the presence of myopia and high myopia at 5 1/2 years of age. CONCLUSIONS: The distribution of refractive errors in preterm infants from age 3 months to 5 1/2 years varies with severity of acute-phase ROP and cicatricial disease. Changes in refractive error distribution occur primarily between 3 months and 1 year and involve a decrease in the proportion of eyes with hyperopia and an increase in the proportion with high degrees of myopia.

Acute Disease↗
PubMed1999

Underestimation of intraocular lens power for cataract surgery after myopic photorefractive keratectomy.

OBJECTIVE: To assess the validity of corneal power measurement and standard intraocular lens power (IOLP) calculation after photorefractive keratectomy (PRK). DESIGN: Nonrandomized, prospective, cross-sectional, clinical study. PARTICIPANTS: A total of 31 eyes of 21 females and 10 males with a mean age at the time of surgery of 32.3 +/- 6.6 years (range, 24.4-49.5 years). INTERVENTION: Subjective refractometry, standard keratometry, TMS-1 corneal topography analysis, and pachymetry were performed before and 15.8 +/- 10.4 months after PRK for myopia (n = 24, -1 .5 to -8.0 diopters [D], mean -5.4 +/- 1.9 D) or myopic astigmatism (n = 7, sphere -2.0 to -7.5 D, mean -4.4 +/- 1.9 D; cylinder -1.0 to -3.0 D, mean -1.9 +/- 0.7 D). The IOLP calculations were done using two different formulas (SRK/T and HAIGIS). MAIN OUTCOME MEASURES: Keratometric power (K) and topographic simulated keratometric power (TOPO) as measured (Kmeas, TOPOmeas) and as calculated according to the change of power of the anterior corneal surface or according to the spherical equivalent change after PRK (Kcalc, TOPOcalc), IOLP for emmetropia, and postoperative ametropia for calculated corneal powers were assessed in a model. RESULTS: After PRK, mean Kmeas and TOPOmeas were significantly greater (0.4-1.4 D, maximum 3.3 D) than mean KRcalc and TOPOcalc (P < 0.0001). On average, the relative flattening of the cornea after PRK was underestimated by 14% to 30% (maximum, 83%) depending on the method of calculation. The mean theoretical IOLP after PRK ranged from + 17.4 D (SRK/T, TOPOmeas) to +20.9 D (HAIGIS, Kcalc) depending on the calculation method for corneal power and IOLP calculation formula used. For both formulas, IOLP values using keratometric readings were significantly higher (>1 D) than IOLP values using topographic readings (P < 0.0001). The theoretically induced mean refractive error after cataract surgery ranged from +0.4 to +1.4 (maximum, +3.1) D. Corneal power overestimation and IOLP underestimation correlated significantly with the spherical equivalent change after PRK (P = 0.001) and the intended ablation depth during PRK (P = 0.004). CONCLUSIONS: To avoid underestimation of IOLP and hyperopia after cataract surgery following PRK, measured corneal power values must be corrected. The calculation method using spherical equivalent change of refraction at the corneal plane seems to be the most appropriate method. In comparison with this method, direct power measurements underestimate corneal flattening after PRK by 24% on average. Use of conventional topography analysis seems to increase the risk of error. However, because this study is retrospective and theoretical, there is still a need for a large prospective investigation to validate the authors' findings.

Adult↗
PubMed1999

Pediatric photoscreening for strabismus and refractive errors in a high-risk population.

OBJECTIVE: To determine the accuracy of the MTI Photoscreener in detecting strabismus and refractive errors in children. PARTICIPANTS: One hundred children underwent MTI photoscreening followed by complete ophthalmologic examination. Six observers graded the photographs for strabismus, according to the location of the corneal light reflexes, and for refractive error, according to the size and location of the light crescent. RESULTS: The sensitivity of the MTI Photoscreener in detecting any amblyogenic factor was 80% to 91%, with a specificity of 20% to 67%. The sensitivity and specificity for particular amblyogenic factors varied widely among observers. The ranges were as follows: strabismus, sensitivity = 23% to 50%, specificity = 76% to 96%; myopia, sensitivity = 89%, specificity = 48% to 76%; hyperopia, sensitivity = 20% to 80%, specificity = 88% to 96%; and astigmatism, sensitivity = 46% to 77%, specificity = 79% to 89%. CONCLUSIONS: These results suggest caution in relying on photoscreening to detect strabismus and refractive errors in children.

Child↗
PubMed1992

Results of photorefractometric screening for amblyogenic defects in children aged 20 months.

This report evaluates the validity of a preventive programme in a population which underwent refractometric screening at the ages of 20 months and 4 years. In 1987, 1,046 children born in 1985 in the territory of the Veneto National Health Unit No. 19 were invited to undergo screening for amblyogenic factors such as meridional hyperopia greater than or equal to +2.50 diopters (D), myopia less than or equal to -2.50 D, anisometropia greater than or equal to 2 D, opacity of the dioptric media and strabismus. The test method was non-cycloplegic photorefractometry (PhR). Seven hundred and ninety-five children were tested (76%); positive cases underwent subsequent cycloplegic autorefractometry (AR) and corrective lenses were prescribed as necessary. In 1989, an eye test was performed on 653 children who had taken part in the previous PhR screening and on 350 similar children who had not: the test included evaluation of visual acuity, stereopsis and AR. An eye with a corrected visual acuity of less than 0.7 was considered amblyopic. PhR demonstrated a sensitivity of 80%, a specificity of 96% and a positive prediction rating of 46% in the identification of amblyogenic factors. The prevalence of amblyopia at 4 years of age in the group which had undergone previous screening was 1.07% vs. 2.57% in the group which had not (P: not significant). The progress of the myopia was studied in a group with full optical correction used continuously (Group A) and in a control group under-corrected by at least 1.5 D (Group B).(ABSTRACT TRUNCATED AT 250 WORDS)

Amblyopia↗
PubMed2006

[Diode laser in "Malignant Glaucoma" treatment].

UNLABELLED: Malignant glaucoma remains one of the most dramatic complications of ocular surgery. It can occur after glaucoma surgery but also after iridotomy, capsulotomy, or cataract extraction. However, the mechanisms remain unclear. PURPOSE: to evaluate diode laser cyclodestruction as a complementary treatment in refractory malignant glaucoma. PATIENTS: Seven women with malignant glaucoma with onset several months before (mean, 43 months; range, 12-96 months), in whom shallow anterior chamber and high IOP (25 mmHg +/- 5.5 treated with 2.86 +/- 0.9 topical and systemic medications) persisted despite prior surgical treatment (mean, 2; range, 1-5). Controlateral eyes had hyperopia (mean, +3.7 D, range, +1 to +6), five had shallow anterior chamber and high IOP. UBM detected plateau iris in four women. METHODS: Seven eyes with malignant glaucoma and three controlateral eyes underwent cyclodestruction with diode laser (Viridis Twin Quantel Medical, laser, 810 nm), 22 burns around 270 degrees , 2 mm from the limbus for glaucomatous eyes and 15 inferior burns for controlateral eyes. RESULTS: Resolution of malignant glaucoma, with lower pressure (mean, 35%; range, 10%-70%), lower levels of medications (64%), final IOP at 13.2 mmHg (+/- 4.7), and deepening anterior chamber was achieved in all cases (mean follow-up, 18 months; range, 12-22). Cycloplegic topical treatment was stopped in 70% of cases. CONCLUSION: Diode laser cyclodestruction can help to resolve refractory malignant glaucoma. Larger UBM studies could help us to better understand the mechanisms of malignant glaucoma.

Adult↗
PubMed2006

[Convergence excess associated with neurological diseases: surgical treatment].

BACKGROUND: Lesions of the supranuclear pathways for convergence control can lead to convergence deficit or convergence excess. Whereas pathophysiology of acquired convergence excess is now fully covered in the literature, no specific paper on its surgical treatment could be found. PATIENTS: Cases 1 and 2: Parinaud's syndrome with convergence excess in attempted upgaze (+ convergence retraction nystagmus and VIth nerve palsy in case 2). Case 3: opsoclonus and convergence excess due to hysterical conversion after head trauma. Case 4: acquired nystagmus, accommodative spasm due to hyperopia. Case 5: functional spasm of the near reflex (dubious medical history of multiple sclerosis). Case 6: medial recti palsy after artificial divergence surgery for congenital nystagmus, substitutive convergence. Cases 3 and 5 were not operated on, recession of the four horizontal recti in case 4, recession of the lateral recti in case 6, complex surgical procedure in cases 1 and 2. DISCUSSION: The following guidelines are suggested: Functional spasm of the near reflex: medical therapy. Organic spasm of the near reflex: retroequatorial myopexia on the medial recti. Parinaud's syndrome with convergence excess (spastic) or convergence retraction nystagmus (rhythmic): restoration of upgaze motility with a vertical Kestenbaum-type procedure, retroequatorial myopexia if insufficient. Thalamic esotropia (tonic): botulinum toxin injection, recession of the medial recti if insufficient. CONCLUSION: Convergence excess associated with neurological diseases should be looked for since it can be improved by effective surgical procedures.

Adolescent↗
PubMed2000

Long-term results of multizone photorefractive keratectomy for myopia of -6.0 to -10.0 diopters.

PURPOSE: To evaluate the 4 year refractive outcome of multizone photorefractive keratectomy (PRK) in eyes with high myopia. SETTING: ++SSK Okmeydani Education Hospital, Eye Clinic, Türkiye Hospital, Okmeydani, Istanbul. METHODS: Three ablation zones were used in 92 eyes of 48 patients whose refractive errors were between -6.0 and -10.0 diopters (D) (mean spherical equivalent -7.42 D +/- 1.25 [SD]). The zones were between 4.5 and 6.0 mm based on the thickness of the cornea and the refractive correction. After the epithelium healed, dexamethasone was applied 4 times a day during the first postoperative week and then fluorometholone was applied 4 times a day for a minimum of 4 weeks. If hyperopia was found post-PRK, the steroid dose was gradually tapered. The patients were examined 1 and 3 days postoperatively, 1, 2, and 4 weeks, every 3 months for the first year, and then every 6 months. RESULTS: All patients were overcorrected in the first postoperative week. At 2 and 3 weeks, the mean manifest refraction was closer to emmetropia. At 6 months, the refraction was stable. The mean spherical equivalent was -0.10 D at the end of the first year, and stabilization continued for 4 years. After the third month, the haze regressed gradually without requiring treatment. In 1 patient, herpes simplex keratitis developed and healed in a short time with topical antiviral therapy. Nineteen eyes regressed more than -1.0 D, 4 eyes were overcorrected, 4 eyes had central islands (at 6 months), and 2 eyes were undercorrected. Two eyes were retreated for regression; 1 eye was retreated for undercorrection and 1 eye, for central island. An uncorrected visual acuity of 20/40 or better was achieved in 79.2% of eyes, and 73.9% were within +/-1. 0 D of the intended correction. CONCLUSION: ++Photorefractive keratectomy was effective in treating high myopia between -6.0 and -10.0 D. The induced refractive changes stabilized between 6 and 9 months. In most patients, no significant regression was found after this period.

Adult↗
PubMed2000

Early clinical experience using custom excimer laser ablations to treat irregular astigmatism.

PURPOSE: To assess the viability of custom excimer laser ablations for treating irregular astigmatism. SETTING: Single-center prospective study of a new custom-ablation technique. METHODS: Twelve patients received 15 custom ablations for irregular astigmatism resulting from keratoconus, penetrating keratoplasty for keratoconus, prior decentered laser in situ keratomileusis, or incisional refractive surgery. Follow-up ranged from 6 weeks to 14 months. Initially, the laser beam was manually decentered; later, the Contoured Ablation Patterns (CAP) method (VISX, Inc.) was used to automatically decenter the ablation over the corneal elevation. RESULTS: Results are presented in a case-by-case fashion. In the manual decentration group, the uncorrected visual acuity (UCVA) was 20/50 or better in 9 of 11 eyes (81.8%) and 20/40 or better in 7 eyes (63.6%). Surgery resolved or decreased visual symptoms when present. The best corrected visual acuity (BCVA) was maintained or improved in all eyes. Persistent </=grade 1 haze developed in the 2 patients (n = 3 eyes) treated for keratoconus. In the CAP group, the UCVA was between 20/40 and 20/80; the BCVA improved in 3 of 4 eyes (75.0%) and declined from 20/20 to 20/25 at 3 months in the remaining eye due to haze. The ablation produced some spherical flattening in both groups, resulting in induced hyperopia that was generally clinically insignificant. CONCLUSION: Early results of this experimental custom-ablation technique are promising.

Adult↗
PubMed2001

Laser in situ keratomileusis after penetrating keratoplasty.

PURPOSE: To assess the outcomes of laser in situ keratomileusis (LASIK) after penetrating keratoplasty (PKP). SETTING: Hospital de Clínicas de Porto Alegre, Department of Ophthalmology, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. METHODS: Fourteen eyes of 13 patients who had LASIK after PKP were retrospectively reviewed. The interval between LASIK and PKP was at least 1 year, and the follow-up after LASIK was also at least 1 year. All patients had a stable refractive error for a minimum of 6 months after all sutures were removed, regular and symmetric topographic astigmatism, and a minimal ultrasonic central corneal pachymetry of 500 microm. The Chiron Automatic Corneal Shaper and the Meditec Aesculap MEL 60 excimer laser were used. RESULTS: At 12 months, mean myopia decreased from -5.33 diopters (D) +/- 4.22 (SD) to 0.19 +/- 1.71 D, mean hyperopia decreased from +5.04 +/- 3.32 D to + 0.42 +/- 0.46 D, and mean astigmatism decreased from 5.37 +/- 2.12 D to 2.82 +/- 2.42 D (47.5% of mean percentage reduction). Retreatment was necessary in 42.9% of eyes because of cylindrical undercorrection. Uncorrected visual acuity improved in 11 eyes (78.6%). Best spectacle-corrected visual acuity improved in 6 eyes (42.8%) and was maintained in 4 eyes (28.6%); 5 eyes (35.7%) lost 1 Snellen line. Intraoperative complications included 1 buttonhole flap. Postoperative complications included interface epithelial ingrowth at the periphery (2 eyes) and pseudophakic retinal detachment 2 years after LASIK (1 eye). CONCLUSION: Laser in situ keratomileusis after PKP safely and predictably corrected the spherical component of the refraction. However, the predictability of LASIK in correcting post-PKP astigmatism was poor.

Adult↗
PubMed2001

Predicting sulcus size using ocular measurements.

PURPOSE: To predict sulcus size using ocular measurements. SETTING: Michel Pop Clinics, Montreal, Quebec, Canada. METHODS: Forty-three eyes were evaluated using several techniques. Ultrasound biomicroscopy (UBM) echograms were taken to measure the anterior chamber depth (ACD), sulcus size, and central corneal thickness. The limbus size was measured with a caliper. Axial length, ACD, and pachymetry were measured by contact ultrasonography. Refraction and corneal power were also evaluated. RESULTS: The coefficient of linear regression was 0.05 between the limbus and the sulcus size (P =.78), 0.76 between ultrasonography and UBM ACD measurements (P <.001), and 0.69 between ultrasonography and UBM pachymetry (P <.001). Paired t tests showed that ultrasound and UBM ACD measurements were not statistically different (P =.70) but that ultrasound and UBM pachymetry measurements were (P <.001). The sulcus versus limbus difference was 0.6 mm for myopia and 0.3 mm for hyperopia. A backward elimination multiple regression performed with all measures to predict sulcus size resulted in the following formula: Sulcus size = 18.9 - 0.023 x sphere + 0.15 x mean keratometry (R = 0.49; P =.005; statistical power = 0.89; standard error of estimate = 0.5 mm). CONCLUSION: Traditional estimation of sulcus size through limbal measurement is inadequate because limbus size alone cannot predict sulcus size. A general formula using the sphere and the mean corneal power can help predict sulcus size. Corneal power was significantly and negatively correlated with sulcus and limbus size as well as sphere. The standard error of sulcus measurement by UBM was 0.4 mm.

Adult↗
PubMed2002

Nonaccommodative esotropia after cataract extraction in a patient with previous accommodative esotropia.

We report a case of nonaccommodative esotropia developing after bilateral cataract surgery that corrected the preexisting hyperopia in a patient with accommodative esotropia since childhood. The esotropia required surgical correction despite the good visual acuity after the cataract surgery. In patients with preexisting strabismus, there is a possibility of decompensation of adaptive binocular mechanisms after cataract surgery and refractive procedures.

Accommodation, Ocular↗
PubMed2002

Reasons for not performing refractive surgery.

PURPOSE: To analyze the reasons that laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) were not performed in patients who requested surgical correction of their refractive errors. SETTING: Minamiaoyama Eye Clinic, Tokyo, Japan. METHODS: This retrospective review comprised 2784 consecutive patients who visited our clinic between June 1997 and August 2000. The reasons they did not receive refractive surgery (PRK or LASIK) were analyzed. RESULTS: Among the 2784 patients who requested surgery for refractive errors, 2079 patients (74.7%) had PRK or LASIK and 705 patients (25.3%) did not. The most common reasons for not treating patients surgically were myopia greater than -12.0 diopters and/or high astigmatism (20.7%), insufficient corneal thickness (8.2%), keratoconus (6.4%), cataract (5.7%), and hyperopia and/or hyperopic astigmatism (4.1%). CONCLUSIONS: Patients who request surgery have a variety of problems. Attention must be given to these individual problems, and the indications must be considered.

Adolescent↗
PubMed2002

Long-term endothelial changes in phakic eyes with posterior chamber intraocular lenses.

PURPOSE: To evaluate the long-term endothelial cell changes in phakic eyes after implantation of a posterior chamber phakic intraocular lens to correct high ametropia. SETTING: Department of Ophthalmology, University Hospital of Vienna, Vienna, Austria. METHODS: Thirty-four eyes of 21 patients having implantation of an implantable contact lens (ICL, Staar Surgical) for high myopia or hyperopia were prospectively examined. The minimum follow-up was 2 to 4 years. Preoperative and serial postoperative specular microscopy (Noncon Robo SP 8000, Konan) was performed to evaluate the long-term endothelial cell changes. RESULTS: The mean preoperative endothelial cell density was 2854 cells/mm(2). The mean endothelial cell loss from preoperatively was 1.8% at 3 months, 4.2% at 6 months, 5.5% at 12 months, 7.9% at 2 years (n = 34), 12.9% at 3 years (n = 13), and 12.3% at 4 years (n = 11). All other endothelial cell characteristics remained stable during the 4-year follow-up. CONCLUSIONS: Continuous endothelial cell loss was observed after ICL implantation during a 4-year follow-up. There was rapid cell loss until 1 year postoperatively, after which the rate of loss was no longer statistically significant. The percentage of hexagonal cells (polymorphism) and the coefficient of variation (polymegethism) remained stable during the 4-year follow-up.

Adult↗
PubMed2003

Intraocular lens power calculation formulas in Chinese eyes with high axial myopia.

PURPOSE: To compare the accuracy of intraocular lens (IOL) power calculation formulas in Chinese eyes with high axial myopia. SETTINGS: Department of Ophthalmology, Tuen Mun Hospital, Hong Kong, China. METHODS: This retrospective study reviewed 125 Chinese patients with high myopia and axial lengths (ALs) longer than 25.0 mm who had cataract surgery during the year 2000. Eyes with pathology or operative complications affecting the refractive status and those with missing data were excluded. In each case, the power of the implanted IOL was used to calculate the predicted postoperative refractive error by 4 IOL power calculation formulas: SRK II, SRK/T, Holladay 1, and Hoffer Q. The predictive accuracy of the formulas was analyzed by comparing the difference between the "actual" and "predicted" postoperative refractive errors. The Student t test was used for statistical analysis. The performance of the formulas in subcategories of long AL was also tested. RESULTS: One hundred twenty-five eyes (110 patients) were studied. Thirty-seven eyes (29.6%) were excluded. The Hoffer Q, Holladay 1, and SRK/T formulas showed a slight tendency toward resultant hyperopia, with a mean of +0.36 diopters (D), +0.53 D, and +0.74 D, respectively. The SRK II caused the largest hyperopic error, with a mean of +1.47 D. All 4 formulas caused a refractive error shift toward myopia in the subcategories of AL >28.0 mm, minus-power IOL, and extracapsular cataract extraction (ECCE). CONCLUSIONS: In Chinese eyes with high axial myopia with an AL longer than 25.0 mm, the 4 formulas caused a slight postoperative hyperopic refractive error that was less in eyes with a minus-power IOL or an AL longer than 28.0 mm and in those that had ECCE. The Hoffer Q formula provided the best predictive result, and Holladay 1 and SRK/T were comparable in IOL power calculation. The SRK II was the least accurate in all subgroups.

Adult↗
PubMed2004

Binocular vision impairment after refractive surgery.

PURPOSE: To illustrate the need for an accurate preoperative orthoptic examination to prevent postoperative changes in binocular vision. SETTING: Department of Ophthalmology, University Hospital Antwerp, Edegem, Belgium. METHODS: Five patients presenting major subjective complaints after refractive surgery were analyzed. RESULTS: In 1 patient, a latent N IV palsy decompensated after laser in situ keratomileusis (LASIK) in the more myopic eye to achieve monovision. A second patient, operated on for N IV palsy 10 years earlier, presented a recurrence of the palsy after bilateral LASIK for myopia. The third patient complained of discomfort in binocular vision caused by aggravation of a preexisting intermittent esotropia that worsened after LASIK for hyperopia. The fourth patient complained of diplopia after LASIK in the highly anisometropic and exotropic eye. The fifth patient experienced a decrease in fusion and stereopsis at the time he became anisometropic after bilateral LASIK. CONCLUSIONS: Special care should be taken of patients who have a preoperative history of strabismus surgery, an overcorrection or undercorrection in 1 or both eyes, or anisometropia and of those who are unhappy with contact lenses. An orthoptic examination should be done with and without spectacle correction to detect underlying vertical phorias. Intended monovision should be examined initially using contact lenses.

Adult↗