Axial length and pharmacologic pupillary dilation in highly myopic patients

PURPOSE

To determine how high myopia impacts pharmacological pupillary dilation, and to evaluate the relationship between the extent of pharmacologic pupillary dilation and axial length.

METHODS

Patients were grouped into high myopes, defined as one or both eyes having a refractive error greater than - 6 diopters, and controls (between - 2 and + 2 diopters). Dilation was achieved with 1 drop each of tropicamide 1% and phenylephrine 2.5%. Pupil size was measured at full and dim light prior to dilation, then 15 and 30 min after dilation. Biometry was measured for each patient. Statistical analyses were performed using the Mann-Whitney-Wilcoxon tests, two-sample Welch's t-tests, and linear mixed effect models and generalized estimating equations models accounting for inter-eye correlation.

RESULTS

Forty patients (20 high myopes and 20 controls, 80 eyes total) participated in the study. High myopes had larger pupils at baseline and achieved significantly greater pupillary size (7.08 mm, 95% CI: 6.97 to 7.19 mm) than controls (6.23 mm, 95% CI: 5.94 to 6.52 mm) after 30 min of dilation (P < .0005). Fully dilated pupil size at 30 min was significantly correlated with both refractive error (r =  - 0.57, P < .0005) and axial length (r = 0.47, P < .0005). Generalized estimating equations and linear mixed effect models identified other predictive variables of pupil size after dilation including age and white-to-white diameter.

CONCLUSIONS

Highly myopic patients dilate to a larger pupillary size compared to other patients. Predicting dilation based on extent of myopia could facilitate intraocular surgery planning and reduce clinic wait times for myopic patients.

[ARTIFICIAL CORNEA: FROM THE BEGINNING TO THE FUTURE]

INTRODUCTION

Corneal disease is among the leading reversible causes of blindness worldwide. Corneal transplantation is a successful and curative treatment for most of these cases. However, in certain indications it is not amendable for standard corneal transplantation, the only available option to restore functional vision is keratoprosthesis (KPro) implantation. KPros may also offer an alternative to the global shortage of donor corneas, limiting the access to transplantations. However, current KPros face many challenges, including surgical complexity that requires skilled surgeons and vast resources as well as unique surgical and post-operative complications. Although several artificial corneas have been proposed over the years, two implants are mostly used in the clinical setting today. The first, the Boston KPro, consists of a front plate with an optical stem and a back plate snapped together with donor corneal tissue in-between, which is then sutured to the patient's cornea. The second, the Osteo-odonto-keratoprosthesis (OOKP), uses biological tissue of the alveolar bone to support an optical cylinder within the eye. The indications, surgical techniques, and complication profile of the two procedures are different and will be discussed in this review. Extensive research continues to improve the accessibility and technological developments of KPros in the search for a potential breakthrough in the treatment of these difficult cases.

Efficacy comparison of combining cross-linking and refractive laser ablation in progressive keratoconus: systematic review and meta-analysis

OBJECTIVE

This study assessed the effect of combining corneal collagen cross-linking (CXL) with refractive laser ablation techniques for the treatment of keratoconus, a progressive corneal disorder.

METHODS

We performed a systematic review and meta-analysis to assess the effect of combined CXL and refractive techniques. We included all published clinical trials or observational studies published by September 1, 2023. We calculated and compared the standardized mean difference (SMD) between CXL alone and CXL plus laser ablation for uncorrected distance visual acuity, best-corrected distance visual acuity, spherical equivalent manifest refraction, sphere and cylinder, flat keratometry (K1), steep keratometry (K2), and central corneal thickness.

RESULTS

We identified 13 studies that fulfilled our inclusion and exclusion criteria. The average follow-up was 21.3 ± 11.8 months. The CXL plus laser ablation group showed improvement in uncorrected distance visual acuity logMAR (SMD, -0.35; 95% CI, -0.67 to -0.04; p = 0.029), best-corrected distance visual acuity logMAR (SMD, -0.17; 95% CI, -0.30 to -0.03; p = 0.014), spherical equivalent manifest refraction (SMD, -0.28; 95% CI, 0.06-0.50; p = 0.013), and change in maximal corneal curvature (Kmax; SMD, -0.41; 95% CI, -0.69 to -0.13; p = 0.004) compared with CXL alone. However, central corneal thickness decreased further among patients who underwent CXL plus laser ablation (SMD, -0.37; 95% CI, -0.66 to -0.07; p = 0.016). No effect was observed in terms of sphere (p = 0.878), cylinder (p = 0.859), K1 (p = 0.907), or K2 (p = 0.169). Ectasia was not observed as an adverse effect resulting from the additional corneal ablation performed during the CXL treatments.

CONCLUSIONS

This study showed that combining refractive laser ablation techniques with standard or accelerated CXL treatment improved visual and refractive outcomes and anterior corneal curvature values.

Corneal pseudoectasia: a case series

OBJECTIVE

To raise awareness of conditions that can tomographically mimic corneal ectasia and describe the actions required to avoid misdiagnosis.

METHODS

We report a retrospective case series of seven patients presenting at two tertiary care centers in Israel with a presumed diagnosis of keratoconus or post-refractive ectasia. Upon further examination, the ectasia diagnosis was reconsidered and eventually ruled out.

RESULTS

Included were ten eyes of seven patients. Cases included bilateral diffuse Salzmann's nodular degeneration, ophthalmoplegia with strabismus which precluded proper fixation during the acquisition of tomography images, two cases of incorrect Pentacam parameter settings, a patient with a history of hyperopic laser-assisted in situ keratomileusis (LASIK) treatment in one eye and myopic LASIK in the fellow eye, a case of old post-photorefractive keratectomy (PRK) stromal haze, and a patient with posterior polymorphous corneal dystrophy.

CONCLUSIONS

Tomography patterns mimicking corneal ectasia can appear in patients without ectatic pathology. The comprehensive ophthalmologist should be aware of such cases as they may substantially alter the treatment course and prognosis of these patients.

ABCD progression display for keratoconus progression: a sensitivity-specificity study

OBJECTIVE

To evaluate the sensitivity and specificity of the ABCD progression display for keratoconus progression.

METHODS

Data was collected from patients that underwent at least two Pentacam assessments 6 months apart. Sensitivity and specificity were calculated for the ABCD progression display. Progression was defined by criterion 1: change in two ABCD parameters above 80% confidence interval (CI) or criterion 2: change in one ABCD parameter above 95%CI. Receiver operating characteristic analysis compared the area under the curve (AUC) of all ABCD parameter combinations.

RESULTS

Thirty eyes were evaluated over a median time of 10.3 months. Progression by criterion 1 resulted in a sensitivity of 61.9% and specificity of 88.9%. Progression by criterion 2 resulted in higher sensitivity (80.9%) and specificity (100%). Pairwise comparisons of the ROC curves show that the AUC achieved by criterion 2 was significantly higher than criterion 1 (0.905 vs. 0.754, p = 0.0332). Evaluation of all ABCD combinations with a significant change of 80% or 95% CI did not show superiority over criterion 1 or 2 regarding progression detection. The D parameter had a very low AUC (0.5-0.556).

CONCLUSIONS

The ABCD progression display can assess keratoconus progression with high sensitivity and specificity, thus assisting the patients' decision-making process. The D parameter did not contribute to the sensitivity or specificity of this classification.

Long-Term Evaluation of Pseudoexfoliation Syndrome Post-Cataract Extraction

The study aimed to examine the effect of cataract extraction on ophthalmologists' ability to detect pseudoexfoliation (PXF) syndrome. A total of 31 patients admitted for elective cataract surgery were enrolled in this prospective comparative study. Prior to surgery, patients underwent slit-lamp examination and gonioscopy conducted by experienced glaucoma specialists. Subsequently, patients were re-examined by a different glaucoma specialist and comprehensive ophthalmologists. Pre-operatively, 12 patients were diagnosed with PXF on the basis of a Sampaolesi line (100%), anterior capsular deposits (83%), and pupillary ruff deposits (50%). The remaining 19 patients acted as controls. All patients were re-examined 10-46 months post-operatively. Of the 12 patients with PXF, 10 (83%) were correctly diagnosed post-operatively by glaucoma specialists and 8 (66%) by comprehensive ophthalmologists. There was no statistically significant difference in PXF diagnosis. However, detection of anterior capsular deposits (p = 0.02), Sampaolesi lines (p = 0.04), and pupillary ruff deposits (p = 0.01) were significantly lower post-operatively. Diagnosis of PXF is challenging in pseudophakic patients as the anterior capsule is removed during cataract extraction. Therefore, PXF diagnosis in pseudophakic patients relies mainly on the presence of deposits at other anatomical sites, and careful attention to these signs is required. Glaucoma specialists may be more likely than comprehensive ophthalmologists to detect PXF in pseudophakic patients.

The first-in-human implantation of the CorNeat keratoprosthesis

OBJECTIVES

To describe the first clinical implantation of the CorNeat™ keratoprosthesis, which utilizes a polymeric scaffold for biointegration within ocular tissue.

METHODS

The CorNeat keratoprosthesis was implanted in the right eye of a patient with bilateral corneal opacification and neovascularization secondary to multiple failed grafts. The following surgical technique was used: 360 degree peritomy; epithelial scraping and corneal marking; pre-placement of three corneo-scleral sutures through the implant; central trephination using a 7 mm trephine and host cornea removal; keratoprosthesis placement and sutures tightening while fitting the corneal edge into the posterior groove of the CorNeat keratoprosthesis; and repositioning of the conjunctiva over the implant skirt and fixation with sutures and Fibrin sealant.

RESULTS

Twelve months postoperatively visual acuity improved to 1/16 from hand movement. The keratoprosthesis was properly positioned. Tactile intraocular pressure was assessed as normal. Regional, mostly nasal, conjunctival retraction of 4-5 mm over the nano-fibre skirt was seen throughout follow-up. The anterior chamber was quiet and well-formed. No other postoperative complications were observed.

CONCLUSION

This initial case may imply a potential breakthrough in the treatment of corneal disease not amenable to standard corneal transplant. Long follow-up and additional implantations are desired to prove the long-term safety and efficacy of this device.

Post-refractive surgery of Israeli Defense Forces recruits in 2005-2018-prevalence, combat unit drop-out rates and utilization of eye-care services

PURPOSE

To assess the number of recruits for military service in the Israeli Defense Force (IDF) who underwent refractive surgery prior to enlistment and examine whether the procedure affected their ability to accomplish combat training.

SETTING

Medical records of IDF recruits.

DESIGN

Retrospective analysis of medical records of recruits with ametropia who underwent or did not undergo refractive surgery prior to enlistment.

METHODS

Recruits were categorized into ametropes and recruits who underwent refractive surgery. Fitness and assignment to combat units and completion status of combat training were compared between the two groups.

RESULTS

The study included 334,688 (182,969 males, 151,719 females) ametropes of which 5231 (4753 males, 478 females) underwent refractive surgery prior to recruitment. Refractive surgery prevalence increased from 9/1000 ametropes in 2005 to 18.5/1000 ametropes in 2018 (r = 0.912, p < 0.001); 2643 of the operated recruits (50.5%) had their surgery at the age of 17-18. Dropout rates from combat training were significantly lower in the refractive surgery group during the study period (1.68% vs. 6.14%, respectively, p < 0.001). Soldiers in the operated group were more frequently referred to ophthalmologists than those in the ametropes group and less frequently referred to optometrists.

CONCLUSIONS

The prevalence of refractive surgery in IDF recruits has increased substantially during the last decade with more of them applying to combat units. Refractive surgery opened new possibilities for recruits who were unfit for combat duty prior to surgery and did not appear to impair the chances of successfully completing combat training.

Validation of the multi-metric D-index change in the assessment of keratoconus progression

PURPOSE

To validate the effectiveness of the multi-metric D-index by Pentacam in detecting keratoconus (KC) progression.

MATERIALS AND METHODS

This was a retrospective study of KC patients at the Rabin Medical Center, Petah Tikva, Israel, during 2016-2018 with at least two corneal tomography examinations six months apart. Agreement between clinical diagnosis of progression (1.5D increase in mean keratometric value, 1D increase in Kmax, a 5% decrease in central corneal thickness (CCT), worsening of visual acuity by more than one line, or deterioration of manifest corneal astigmatism > 1.5D) and the D-index was evaluated. Receiver operating characteristic (ROC) analysis was used to find the D-index's optimal cutoff value to show progression.

RESULTS

We included KC eyes in the stable group (N = 7) and the progression group (N = 54). Patient demographics and tomographic parameters at baseline were similar between the groups. The D-index change was significantly higher in the progression group than in the stable group (median + 1 and 0.0, respectively, p = 0.024). Based on the ROC analysis, the optimal D-index cutoff change within at least six months was 0.32 (59.3% sensitivity and 100% specificity (area under the curve [AUC] = 0.771, Youden = 0.592). Subjects with a D-index change above this value had a 21.1-fold increase in odds for corneal ectasia progression requiring CXL (OR: 21.1, 95%CI 1.17-398.8, p = 0.038).

CONCLUSION

The multi-metric D-index can serve as a clinically feasible parameter to detect KC progression and guide patients' referral for further interventions.

Descemet Membrane Endothelial Keratoplasty in Eyes With Chronic Ocular Hypotony Following Glaucoma Surgery

PURPOSE

To assess the outcomes of Descemet membrane endothelial keratoplasty (DMEK) in patients with ocular hypotony after glaucoma surgery.

DESIGN

retrospective case series.

METHODS

Setting: Multicenter retrospective case series.

PATIENTS/INTERVENTION

Hypotonic eyes with prior glaucoma surgery that underwent DMEK between January 2013 and July 2019 in Israel (2 centers) and Canada (1 center).

MAIN OUTCOME MEASURES

Pre/postoperative corrected distance visual acuity, complications, 3- to 6-month endothelial cell loss, and intraocular pressure (IOP).

RESULTS

The study included 11 DMEK procedures performed in 10 eyes of 4 males and 6 females aged 65-84 years. Indications for DMEK included 7 cases of pseudophakic bullous keratopathy, 2 cases of failed DMEK, and 1 case of failed Descemet stripping automated endothelial keratoplasty. All patients had at least 1 previous trabeculectomy operation. One patient had 2 trabeculectomy procedures and 1 tube placement procedure. Two patients had 1 previous trabeculectomy and 1 tube placement procedure. The corrected distance visual acuity improved significantly from 1.52 ± 0.68 logarithm of minimal angle of resolution preoperatively to 0.49 ± 0.32 logarithm of minimal angle of resolution 3 months postoperatively (P < .001). Rebubbling occurred in 3 of 11 procedures (27%). Endothelial cell loss 6-12 months postoperatively was 60% ± 16% (range, 41%-89%). At the last follow-up visit, 6 of 11 (54%) of the grafts were clear. The remaining 5 grafts failed at 1-4 years postoperatively. The preoperative IOP was 5.1 ± 1.6 mm Hg (range, 1-7 mm Hg). In all but one patient, the postoperative IOP did not increase to more than 13 mm Hg. In 2 cases, the IOP decreased from 5 and 7 mm Hg preoperatively to 1 mm Hg 1 year postoperatively.

CONCLUSION

DMEK is a valid procedure for the treatment of corneal edema in hypotonic eyes after glaucoma procedures. These eyes benefit from improvement in vision after DMEK.

Outcomes of Repair of Total Graft Detachment following Descemet's Membrane Endothelial Keratoplasty

OBJECTIVE

To present the outcomes of attempts to salvage total graft detachment following Descemet's membrane endothelial keratoplasty (DMEK).

METHODS

A search of the electronic medical records of two tertiary medical centers for all patients who underwent DMEK yielded six cases of postoperative total graft detachment (2.54%). Graft salvage was attempted in all cases using repeated intracameral graft staining, unfolding, and reattachment to the stroma under 20% hexafluoride gas.

RESULTS

In all cases, a free-floating totally detached graft was identified in the anterior chamber shortly after surgery. Salvage surgery resulted in a central, well-oriented, and fully attached graft. In three cases, the primary graft failed, and in two, the corneas cleared at first but failed after 2 months and 1 year respectively. In one case, the cornea remained clear during 1 year of follow-up but had a very low endothelial cell density.

CONCLUSION

Reattachment of fully detached DMEK graft is technically possible, but graft manipulation during the primary and secondary operations is likely to damage the endothelial cells, resulting in primary or early graft failure. If graft salvage is attempted, the probability of primary or early graft failure should be discussed with the patient, and expectations should be tempered accordingly.

Transepithelial photorefractive keratectomy on the same day of the initial consultation for the correction of myopia

PURPOSE

To examine the clinical outcomes, efficacy, safety, and predictability of transepithelial photorefractive keratectomy (Trans-PRK) operations performed on the day of the first screening visit in comparison with operations scheduled at a following appointment.

METHODS

Data of consecutive patients with myopia of various degrees, who underwent Trans-PRK, were retrospectively analyzed. Findings were compared between patients who underwent Trans-PRK on the same day of first consultation to patients that underwent surgery at subsequent visits, following initial consultation on a different day.

RESULTS

The study included 599 eyes treated on the initial visit day and 1936 eyes treated on a subsequent visit. Mean final spherical equivalent was close to emmetropia in both groups (p = 0.183). Efficacy indices were 0.928 ± 0.192 in the initial-visit group and 0.945 ± 0.163 in the second-visit group (p = 0.152). Safety indices were 0.954 ± 0.156 and 0.955 ± 0.151 (p = 0.707), respectively. No differences between the groups were seen in uncorrected visual acuity (UDVA) of ⩾20/20, ⩾20/25, and ⩾20/32. Only the sub-analysis of patients reaching UDVA of 20/40 or better was slightly lower in the first-visit (95.5%) compared with the second-visit group (97.9%, p = 0.001). Results of attempted correction within ±0.50 D were: 63.3% and 69.0%, respectively (p = 0.009). Complications profiles in the two groups were comparable.

CONCLUSIONS

Trans-PRK completed on the day of the first screening appointment demonstrated a similar safety outcome compared with subsequent-visits procedures, and slightly lower, yet comparable, results regarding efficacy and predictability.

Descemet Membrane Endothelial Keratoplasty Outcomes between Young and Old Graft Recipients

Purpose: To evaluated Descemet's membrane endothelial keratoplasty (DMEK) outcomes in young and old graft recipients.Materials and Methods: Data of 164 surgeries with a median age of 76 years (interquartile range 14 years) undergoing DMEK surgery between 2016 and 2018 was reviewed. Complications, graft survival, and visual acuity gain were compared between subjects in the 25th percentile (young recipients; aged 70 years and less, n = 21) and 75th percentile (old recipients; aged 85 years and over, n = 27) over the 2-year follow-up.Results: Young recipients had a lower rate of pre-operative glaucoma (14.3% vs. 51.9%, p = .014) and pseudophakic bullous keratopathy (9.5% vs. 59.3%, p < .001), and a higher rate of Fuchs endothelial dystrophy (57.1% vs. 14.8%, p = .002) and combined cataract extraction at the time of DMEK surgery (52.4% vs. 7.4%, p = .001) when compared to old recipients. Complications (primary graft failure, pupillary block, cystoid macular edema or infectious keratitis) were independent of graft recipient age. Descemet's membrane detachment requiring re-bubbling was observed more often in young compared to the old recipients (42.9% vs. 14.8%, p = .049). Visual acuity gain between the groups remained comparable up to 1-year, whereas at 2-years old recipients showed significantly declined visual acuity gains compared to the young recipients (0.14 ± 0.68 vs. 0.74 ± 0.49, p = .012). Graft recipients aged over 85 years had a considerably higher graft failure rate over the 24-months (40.7% vs. 4.8%, p = .006) and shorter graft survival time (p = .002; log-rank) when compared to the recipients aged under 70 years. After adjusting for potential confounders such as Fuchs endothelial dystrophy, pseudophakic bullous keratopathy and glaucoma, the recipients aged over 85 remained at higher risk for graft failure (HR = 17.278, 95% CI = 1.787-167.1, p = .014).Conclusions: In aged DMEK recipients, regardless of the low incidence of early postoperative complications, the rate of postoperative graft failure was significantly higher and graft survival shorter than in younger recipients.

Effect of Penetration Angle and Velocity During Intravitreal Injection on Pain

Purpose: To evaluate the effect of velocity and angle of the intravitreal injection of anti-vascular endothelial growth factors on pain sensation.Methods: Patients were randomly assigned to one of four injection methods: straight and fast, straight and slow, tunneled and fast, and tunneled and slow. Later, they graded their pain sensation on a Visual Analog Scale (range 0-10).Results: The cohort included 180 patients. Mean pain score was 2.81 ± 2.34. There was no statistically significant difference in mean pain score among the four groups (p = .858); between the slow-injection (straight and tunneled) and fast-injection groups (p = .514); and between the straight-injection (fast and slow) and tunneled-injection groups (p = .992), nor other background variables.Conclusion: Velocity and angle of intravitreal injections are unrelated to the pain sensation. Therefore, the method may be left to the clinician's discretion. This implies that the sensation is mostly subjective.

High Agreement between Barrett Universal II Calculations with and without Utilization of Optional Biometry Parameters

Purpose: To examine the contribution of anterior chamber depth (ACD), lens thickness (LT), and white-to-white (WTW) measurements to intraocular lens (IOL) power calculations using the Barrett Universal II (BUII) formula. Methods: Measurements taken with the IOLMaster 700 (Carl Zeiss, Meditec AG, Jena, Germany) swept-source biometry of 501 right eyes of 501 consecutive patients undergoing cataract extraction surgery between January 2019 and March 2020 were reviewed. IOL power was calculated using the BUII formula, first through the inclusion of all measured variables and then by using partial biometry data. For each calculation method, the IOL power targeting emmetropia was recorded and compared for the whole cohort and stratified by axial length (AL) of the measured eye. Results: The mean IOL power calculated for the entire cohort using all available parameters was 19.50 ± 5.11 diopters (D). When comparing it to the results obtained by partial biometry data, the mean absolute difference ranged from 0.05 to 0.14 D; p < 0.001. The optional variables (ACD, LT, WTW) had the least effect in long eyes (AL ≥ 26 mm; mean absolute difference ranging from 0.02 to 0.07 D; p < 0.001), while the greatest effect in short eyes (AL ≤ 22 mm; mean absolute difference from 0.10 to 0.21 D; p < 0.001). The percentage of eyes with a mean absolute IOL dioptric power difference more than 0.25 D was the highest (32.0%) among the short AL group when using AL and keratometry values only. Conclusions: Using partial biometry data, the BUII formula in small eyes (AL ≤ 22 mm) resulted in a clinically significant difference in the calculated IOL power compared to the full biometry data. In contrast, the contribution of the optional parameters to the calculated IOL power was of little clinical importance in eyes with AL longer than 22 mm.

Real-time intraoperative ultrasound biomicroscopy for determining graft orientation during Descemet's membrane endothelial keratoplasty

PURPOSE

To evaluate the intraoperative use of ultrasound biomicroscopy (UBM) during Descemet's membrane endothelial keratoplasty (DMEK) to determine graft's orientation.

METHODS

Prospective interventional study of eight eyes of seven patients who underwent DMEK. Following the identification of correct graft orientation using 'Blue cannula tip' sign during DMEK surgery, UBM was used to ascertain graft's orientation. The rate of successful DMEK graft orientation determined by the UBM was registered and verified postoperatively by anterior segment-optical coherence tomography (OCT). Intra- and postoperative complications, postoperative clearance of the cornea, corrected distance visual acuity and endothelial cell loss were also noted.

RESULTS

The study included five males and two females aged 54-82 years with corneal oedema due to Pseudophakic bullous keratopathy (n = 5), Fuchs' endothelial dystrophy (n = 2). In all cases, the technique allowed proper determination of the graft's orientation. In one case, 'blue cannula tip' sign showed correct orientation while UBM identified an upside-down graft. The graft was inverted in the anterior chamber using fluid jets, and repeat 'blue cannula tip' sign and UBM examination both showed correct orientation. In all cases, postoperative anterior segment-OCT demonstrated correct graft orientation.

CONCLUSIONS

Use of intraoperative UBM to determine graft orientation during DMEK correlated with proper graft orientation, as was verified postoperatively by anterior segment-OCT. The use of UBM can be particularly helpful in cases of poor graft visibility due to opaque corneal stroma, pigment or blood in the anterior chamber during surgery, or when the blue tint of the graft fades rapidly, which may preclude proper determination of graft's orientation.

Femtosecond laser assisted in situ keratomileusis (FS-LASIK) yields better results than transepithelial photorefractive keratectomy (Trans-PRK) for correction of low to moderate grade myopia

INTRODUCTION

The purpose of this study was to compare the outcomes of transepithelial photorefractive keratectomy (Trans-PRK) with femtosecond laser assisted in situ keratomileusis (FS-LASIK) for the correction of low to moderate myopia.

METHODS

A retrospective cohort study design was used. The study group included patients with myopia less than -6.0 D, with or without concomitant astigmatism under 2.0 D, who were treated with FS-LASIK or Trans-PRK in 2013 through 2014. Background, clinical and outcome data were collected from the patient files. A comparison between eyes treated with FS-LASIK or Trans-PRK was performed.

RESULTS

The Trans-PRK group was comprised of 1793 eyes and the FS-LASIK group of 666 eyes. Mean ± SD spherical equivalent (SE) refraction prior to surgery was -3.43 ± 1.27 D in the Trans-PRK group and -3.18 ± 1.34 D in the FS-LASIK group (p < 0.001). Efficacy index values were 0.95 ± 0.14 in the Trans-PRK group and 0.98 ± 0.12 in the FS-LASIK group (p < 0.001), and corresponding safety index values were 0.96 ± 0.13 and 0.99 ± 0.12 (p < 0.001). Distance from target refraction was 0.45 ± 0.42 D in Trans-PRK group and 0.43 ± 0.38 D in the FS-LASIK group (p = 0.537); 71.6% and 74.2% of eyes were within ±0.5 D of attempted correction, respectively (p = 0.193).

CONCLUSIONS

Both Trans-PRK and FS-LASIK demonstrated excellent results, mostly comparable with the current literature. FS-LASIK achieved better results than Trans-PRK surgery in the efficacy and safety parameters.

Refractive outcomes of high-magnitude astigmatism correction using femtosecond LASIK versus transepithelial PRK

PURPOSE

To compare the outcomes of femtosecond laser assisted in situ keratomileusis (FS-LASIK) with transepithelial photorefractive keratectomy (T-PRK) for the correction of high-grade astigmatism.

METHODS

Medical records of patients with astigmatism of 2 diopters (D) or higher, who were treated with FS-LASIK or T-PRK in 2013 through 2014 at a private practice laser clinic, were retrospectively analyzed. Efficacy, safety, predictability and vector analysis of astigmatism correction were compared between the treatment groups.

RESULTS

The study included 93 eyes treated with FS-LASIK and 186 eyes treated with T-PRK. No significant differences in postoperative spherical equivalent (-0.10 ± 0.7 D and -0.11 ± 0.7 D, respectively, p = 0.958) and postoperative refractive astigmatism (0.79 ± 0.54 D and 0.82 ± 0.63 D, respectively, p = 0.685) were demonstrated. A significant advantage of FS-LASIK over T-PRK was seen for the efficacy (1.00 ± 0.18 and 0.86 ± 0.22, respectively, p < 0.001) and safety (1.03 ± 0.17 and 0.89 ± 0.21, respectively, p < 0.001) indices. Results remain statistically significant in a multivariate analysis model. Vector analysis for the astigmatism correction showed no significant difference between the surgery methods in the surgically induced astigmatism, difference vector, correction index and index of success.

CONCLUSION

Both procedures demonstrated desirable post-operative SE outcomes for high-grade astigmatism correction. However, FS-LASIK achieved better results than T-PRK in the efficacy and safety parameters.

Refractive outcomes following cataract combined with lamellar keratoplasty: femtosecond-DSEK versus microkeratome-DSAEK

PURPOSE

Prediction of postoperative refraction following posterior lamellar keratoplasty is crucial for choosing proper intraocular lens power in combined surgeries. Femtosecond laser-assisted Descemet stripping endothelial keratoplasty (FS-DSEK) creates thin, planar grafts while microkeratome-assisted Descemet's stripping automated endothelial keratoplasty (DSAEK) creates non-planar, concaved grafts. We evaluated whether this fundamental difference affects the refractive outcomes in cataract surgery combined with FS-DSEK compared to cataract surgery combined with microkeratome-assisted DSAEK.

METHODS

A retrospective analysis of 28 patients who underwent FS-DSEK combined with phacoemulsification and intraocular lens (IOL) implantation (group A) compared to 26 patients who underwent microkeratome-assisted DSAEK combined with phacoemulsification and IOL implantation (group B). Pre- and 1-year postoperative best-corrected visual acuity (BCVA), keratometry values, corneal thickness, central-to-peripheral graft thickness ratio (C/P ratio), and target postoperative spherical equivalent (SE) versus actual postoperative SE were analyzed.

RESULTS

Target postoperative SE and actual postoperative SE significantly shifted toward hyperopia in group B, but not in group A. Postoperative hyperopic shifts were 0.14 D and 1.13 D in groups A and B, respectively (P < 0.001). BCVA improved after surgery in both groups, with no significant difference between the groups. Postoperative C/P ratio differed significantly between the groups and was negatively correlated with postoperative hyperopic shift (r =  - 0.616, P < 0.001).

CONCLUSION

Refractive outcomes of cataract surgery combined with FS-DSEK are relatively neutral, whereas those of cataract surgery combined with microkeratome-assisted DSAEK cause significant hyperopic shift. Clinicians should select accordingly an appropriate intraocular lens power when performing these surgeries.

Changes in anterior segment parameters following insertion of ExPRESS mini glaucoma implant vs. trabeculectomy

PURPOSE

To compare changes in anterior segment parameters following ExPRESS Mini Glaucoma Shunt surgery vs. trabeculectomy using the Pentacam rotating Scheimpflug camera.

METHODS

In this prospective, comparative study, 27 patients with glaucoma treated at the Rabin Medical Center from 2009 to 2013 were enrolled in this prospective comparative study: 19 participants (19 eyes) underwent ExPRESS shunt implantation and 12 (13 eyes) underwent trabeculectomy. Changes in anterior chamber parameters at postoperative day 1 and postoperative month 3 were evaluated on Scheimpflug images.

RESULTS

Intraocular pressure decreased significantly from baseline in both groups. The decrease in both groups was similar at postoperative month 3 (p=0.82). ExPRESS surgery caused a transient increase in posterior corneal astigmatism (p=0.008) and a transient decrease in anterior chamber depth (p=0.016) and volume (p=0.006) on postoperative day 1. At postoperative month 3, these parameters were no longer statistically significant (p=0.65, p=0.51, and p=0.57 respectively). Trabeculectomy caused a transient increase in anterior and posterior corneal astigmatism on postoperative day 1 (p=0.003 and p=0.005, respectively), which were not evident at postoperative month 3 (p=1.0 and p=1.0, respectively). At postoperative month 3, both ExPRESS and trabeculectomy showed similar changes in anterior chamber parameters.

CONCLUSIONS

Both ExPRESS mini glaucoma implant and trabeculectomy significantly decreased intraocular pressure and had transient effects on anterior segment parameters, with minor differences between the methods.

Research productivity across different ophthalmic subspecialties in the United States

Background

The purpose of this study was to compare the h-index, and subsequently the research productivity, among different ophthalmic subspecialties in the United States.

Methods

A cohort of over 15,000 academic ophthalmologists residing in the United States (US) was identified out of the physician list of the American Academy of Ophthalmology. Of them, 1000 ophthalmologists with at least one publication were randomly retrieved, 100 in each of the following 10 subspecialties: cataract, cornea/external disease, glaucoma, medical retina, neuro-ophthalmology, pediatric ophthalmology, plastic/reconstructive ophthalmology, refractive surgery, retina/vitreous surgery and uveitis. Data collected included: number of published papers, h-index score, annual increase in h-index and the mean number of authors on each paper.

Results

The mean h-index amongst all subspecialties was 9.87 ± 13.90, and the mean average annual increase in h-index was 0.22 ± 0.21. The mean number of papers published was 37.20 ± 80.08 and the mean number of authors on each paper was 3.39 ± 0.84. Uveitis was the most prolific subspecialty in mean number of papers (74.78 ± 131.37), in mean h-index (16.69 ± 20.00) and in mean annual increase in h-index (0.35 ± 0.28). The least fertile subspecialty with regards to research was cataract with 11.06 ± 27.65 mean number of papers, a mean h-index of 3.89 ± 5.84, and a mean annual increase in h-index of 0.11 ± 0.11.

Conclusions

This study describes the research productivity in each ophthalmic subspecialty in the US, thus providing information on the research performance of each field and on the expected academic accomplishments within it.

Dupilumab-induced ocular surface disease (DIOSD) in patients with atopic dermatitis: clinical presentation, risk factors for development and outcomes of treatment with tacrolimus ointment

Aim

To identify risk factors for the development of dupilumab-induced ocular surface disease (DIOSD) in adult patients with atopic dermatitis (AD) and describe outcomes of treatment.

Methods

A retrospective institutional cohort study performed at the Rabin Medical Center, Petach Tikva, Israel. Adult patients with AD who received dupilumab from March 2018 to June 2019 were included. Demographics, AD severity scores, blood IgE levels, previous atopic keratoconjunctivitis (AKC), dermatological response to dupilumab, ophthalmological evaluation and treatment were noted. Univariate and multivariate analyses were used to identify risk factors for DIOSD.

Results

Sixteen of 37 patients who were included in the study (43%) had new or exacerbated symptoms of ocular surface disease starting at 2 weeks following the first treatment. Three patients reported transient dry eye sensation which lasted 2 weeks; nine patients reported chronic dry eye sensation, and four patients (25%) had marked blepharoconjunctivitis. The presence of severe AD was the strongest predictor of DIOSD. Not a single patient with moderate AD had DIOSD. In multivariate analysis, prior AKC was a risk factor for DIOSD (R2=15.78, OR=23.28, p=0.005) while a family history of atopy was protective of DIOSD (R2=6.22, OR=0.13, p=0.05). All four patients with blepharoconjunctivitis had resolution of signs, and symptoms within days of starting periocular 0.03%–0.1% tacrolimus ointment.

Conclusions

DIOSD is common in patients with AD receiving dupilumab. While most cases are mild, some patients can develop blepharoconjunctivitis which responds well to tacrolimus ointment. AD severity, and previous AKC are risk factors for DIOSD.

Comparative analysis of biomechanical parameters of the corneas following Descemet membrane endothelial keratoplasty and contralateral healthy corneas

PURPOSE

To compare the biomechanical properties of the unilateral operated corneas in patients who had undergone Descemet membrane endothelial keratoplasty (DMEK) for pseudophakic bullous keratopathy (PBK) with those of the contralateral normal corneas.

METHODS

This was a retrospective cohort study conducted at university hospitals (Department of Ophthalmology, Rabin Medical Center, Petach Tikva, Israel, and S. Fyodorov Eye Microsurgery State Institution, Moscow, Russia). Forty eyes of 20 patients who underwent DMEK for unilateral PBK 3.5 to 36 months ago and with normal fellow eyes were included in the study. An ocular response analyzer was used to measure the corneal biomechanical properties in the operated and normal fellow eyes. The main outcome measures were corneal hysteresis (CH) and corneal resistance factor (CRF).

RESULTS

The mean CH (8.4 ± 1.5 mmHg vs. 8.2 ± 1.5 mmHg, P = 0.707) and the mean CRF (8.7 ± 1.6 mmHg vs. 8.3 ± 1.6 mmHg, P = 0.419) values did not show any statistically significant difference between the operated and the normal fellow eyes.

CONCLUSIONS

In our study, the corneas that underwent DMEK for PBK showed normal values for biomechanical parameters. These findings support the previous studies that have reported near complete visual, functional, and ultra-structural rehabilitation of the corneas following DMEK.

Comparison of Subconjunctival Aflibercept and Betamethasone for the Treatment of Formed Corneal Neovascularization in a Rabbit Model

AIM

To compare the efficacy of aflibercept (Eylea®), a potent antivascular endothelial growth factor (VEGF) agent, with betamethasone (Celestone®) and placebo for the treatment of formed corneal neovascularization in a rabbit model.

METHODS

A central corneal chemical burn was created in the right eye of 24 New Zealand albino rabbits. Four weeks later, the rabbits were randomly divided into 4 equal groups for subconjunctival injection of aflibercept, betamethasone, aflibercept+ betamethasone, or saline (control). Digital photographs taken at weekly intervals were rated by 2 masked observers for extent, centricity, and density of corneal neovascularization according to a predefined scale. The percentage of corneal surface involved by neovascularization was quantified by image analysis software (Fiji-J). The change in corneal neovascularization from treatment administration (4 weeks after injury) to 4 weeks later (8 weeks after injury) was assessed. The rabbits were then euthanized, and their eyes were enucleated and processed for histopathological and immunofluorescence studies.

RESULTS

There was no significant difference in the change in corneal neovascularization after treatment among the 4 groups according to the digital images (p > 0.15) or histological evaluation with hematoxylin and eosin (p > 0.08). On immunofluorescence assay, a lower VEGF concentration was observed in all treatment groups compared to the control group.

CONCLUSIONS

In this rabbit model, corneal neovascularization induced by chemical burn failed to regress with treatment with aflibercept, betamethasone, or their combination.

Corneal Endothelial Decompensation after Ocular Chemical Burn: Description of a New Finding

BACKGROUND

Ocular chemical burn is an ophthalmological emergency. Therefore, chemical injuries should be promptly addressed in order to initiate the appropriate treatment as soon as possible and optimize the visual prognosis. We present a retrospective study of ten cases with ocular chemical burn including one with superglue and one with a liquid plaster material injury and describe their clinical course.

HISTORY AND SIGNS

Ten adult patients (34 - 92 years, 8 males) presented with moderate to severe alkali or neutral chemical burns in our emergency clinics. They exhibited a variable degree of conjunctival injection, limbal ischemia, corneal erosion, and Descemet's folds.

THERAPY AND OUTCOME

Patients were treated and complete corneal epithelial closure was achieved in all cases without significant signs of limbal stem cell insufficiency. Corneal endothelial insufficiency was observed in all cases. Nine patients had to be listed for corneal endothelial keratoplasty and one was treated with Descemet's stripping endothelial automated keratoplasty.

CONCLUSIONS

Isolated corneal endothelial decompensation after chemical burns has not yet been described. The pathophysiological explanation of this observation remains, however, unknown. In view of this rare complication, it is important to follow patients after chemical ocular burn for possible development of endothelial decompensation.

[PREVALENCE OF DEMODEX PARASITES IN PATIENTS WITH CHRONIC BLEPHARITIS AND HEALTHY CONTROLS IN ISRAEL]

INTRODUCTION

Previous studies demonstrated the potential pathogenic relationship between infestation of the eyelashes by the parasite Demodex and chronic blepharitis, whereas other studies did not demonstrate such relations and concluded that Demodex is a normal eyelid flora.

AIMS

This study examines the prevalence of Demodex in patients with blepharitis compared to a healthy control group in Israel, in order to further explore and establish its pathogenic role in cases of chronic blepharitis.

METHODS

A case-control study was conducted including 110 participants: 60 patients with chronic blepharitis attending a tertiary medical center and 50 subjects with no signs of blepharitis. Six to eight eyelashes were epilated from each participant and studied microscopically for the presence of Demodex by a blinded examiner. Fluorescein stain was added to the "clean" samples in order to reduce the false negative results.

RESULTS

Demodex were identified on the eyelashes of 44 patients with blepharitis (73.3%) and 20 controls (40%) (p<0.001). After adjusting for age, blepharitis was still a significant risk factor for the presence of Demodex (OR=2.96, CI 95% 1.2-7.3).

CONCLUSIONS

This study supports previous studies demonstrating pathogenic relationship between Demodex infestation of the eyelashes to chronic blepharitis. The authors recommend epilating 6-8 lashes of patients with blepharitis for microscopic identification of these parasites. Fluorescein stain may have a limited role in the recognition of Demodex in parasite free samples.

'Blue bubble' technique: an ab interno approach for Descemet separation in deep anterior lamellar keratoplasty using trypan blue stained viscoelastic device

BACKGROUND

In this study, we examined a novel variant of 'big-bubble' deep anterior lamellar keratoplasty using trypan-blue-stained viscoelastic device for the creation of a pre-descemetic bubble.

METHODS

Ten corneoscleral rims were mounted on an artificial anterior chamber (AC). The AC was filled with air through a limbal paracentesis. A Melles' triangulated spatula was inserted through the paracentesis, with its tip penetrating the AC, was then slightly retracted and pushed into the deep stroma above the roof of the paracentesis. A mixture of trypan blue and viscoelastic device (Healon, Abbott Medical Optics, Abbott Park, Illinois) was injected into this intra-stromal pocket using a 27-G cannula to create a pre-descemetic separation bubble. Bubble type and visualization of dyed viscoelastic device were noted. The method was later employed in three cases.

RESULTS

In all 10 corneoscleral rims, the technique successfully created a visible pre-descemetic (type 1) bubble that could be expanded up to the predicted diameter of trephination. Subsequent trephination and the removal of corneal stroma were uneventful. In two out of four clinical cases, a type 1 bubble was created, while in two others, visco-dissection failed and dyed viscoelastic was seen in the AC.

CONCLUSIONS

The presented technique holds promise of being a relatively easy to perform, predictable and well-controlled alternative for achieving a type 1 bubble during deep anterior lamellar keratoplasty surgery. The trypan-blue-stained viscoelastic device facilitates proper visualization and control of the separation bubble and assists in identifying the penetrance to the separation bubble prior to removal of the stromal cap.

Laser capsulotomy following cataract surgery: Comparing time to capsulotomy with implantation of two broadly used intraocular lenses

PURPOSE

The aim of this study is to compare the length of time from uneventful cataract surgery using one of two common posterior chamber intraocular lenses (IOLs) (hydrophilic versus hydrophobic acrylic) to laser capsulotomy.

MATERIALS AND METHODS

Retrospective analysis of all patients who underwent neodymium: yttrium-aluminum-garnet laser capsulotomy between 2011 and 2014 following uneventful phacoemulsification surgery at a tertiary university-affiliated medical center. Medical records were reviewed for demographics, ocular comorbidities, operative details, postoperative follow-up, and findings of the precapsulotomy ophthalmologic examination. Parameters, including age, sex, laterality, visual acuity, surgeon's experience, and time from cataract surgery to capsulotomy, were compared between patients who received hydrophilic (SeeLens AF, Kibbutz Hanita, Israel) or hydrophobic (AcrySof SA60AT, Alcon Laboratories, Fort Worth, TX, USA) IOLs.

RESULTS

The cohort included 222 patients (255 eyes), of which, 107 were male and 115 female, of mean age 73 ± 8 years. Mean interval from cataract surgery to laser capsulotomy was 24 months (range 2-70) and was significantly shorter in patients with SeeLens (23 ± 13 months) than AcrySof IOL implantation (28 ± 13 months, P = 0.04). Lens type remained significant in multivariate analysis after including surgeon's experience and age as potential confounders (P = 0.04).

CONCLUSION

The hydrophilic SeeLens IOL is associated with a significantly shorter time interval from cataract surgery to laser capsulotomy than the hydrophobic AcrySof IOL.

Effect of Histone Deacetylase Inhibitor, Butyroyloxymethyl-Diethyl Phosphate (AN-7), on Corneal Neovascularization in a Mouse Model

PURPOSE

To examine whether butyroyloxymethyl-diethyl phosphate (AN-7), a histone deacetylase inhibitor, inhibits chemically induced corneal neovascularization (NV) in mice.

METHODS

Corneal NV was induced in the right eye of male C57BL mice by application of a mixture of 75% silver nitrate and 25% potassium nitrate to the corneal center. Immediately thereafter, the mice were randomized into 2 groups, receiving an intraperitoneal injection of AN-7 or saline, which served as control. Corneal NV was evaluated at constant time intervals from the corneal injury by corneal photographs and the area of corneal NV was measured. Centricity and density of the corneal vascularization were graded. Corneal flat mounts blood vessels staining and histological studies were performed on day 10. Unpaired t-test was used for group comparisons.

RESULTS

The corneal neovascular area was statistically significantly reduced by AN-7 treatment on days 10 and 14 postinjury and compared with the untreated group. The centricity and density of the corneal NV between treated and untreated groups showed no significant difference at any time point.

CONCLUSIONS

Systemic treatment with AN-7 had a significant inhibitory effect on chemical burn-induced corneal NV in mice. These results suggest that AN-7 should be further evaluated for its therapeutic potential for the treatment of corneal NV.

CO₂ laser welding of corneal cuts with albumin solder using radiometric temperature control

PURPOSE

To examine the efficacy and reproducibility of CO₂ laser soldering of corneal cuts using real-time infrared fiber-optic radiometric control of tissue temperature in bovine eyes (in vitro) and to evaluate the duration of this procedure in rabbit eyes (in vivo).

METHODS

In vitro experiment: a 6-mm central perforating cut was induced in 40 fresh bovine eyes and sealed with a CO₂ laser, with or without albumin soldering, following placement of a single approximating nylon suture. A fiber-optic radiometric temperature control system for the CO₂ laser was used. Leaking pressure and histological findings were analyzed and compared between groups. In vivo experiment: following creation of a central perforation, 6 rabbit eyes were treated with a CO₂ laser with albumin solder and 6 rabbit eyes were treated with 10-0 nylon sutures. The amount of time needed for completion of the procedures was compared.

RESULTS

In vitro experiment: effective sealing was achieved by CO₂ laser soldering. Mean (± SD) leaking pressure was 109 ± 30 mm Hg in the bovine corneas treated by the laser with albumin solder compared to 51 ± 7 mm Hg in the sutured control eyes (n = 10 each; p < 0.001). Mean leaking pressures were much lower in the corneal cuts sealed only with the laser without albumin solder (48 ± 12 mm Hg) and in the cuts sealed only with albumin without laser welding (6.3 ± 4 mm Hg) than in the cuts treated with laser welding and albumin solder. In vivo experiment: mean surgical time was 140 ± 17 s in the laser-treated rabbits compared to 330 ± 30 s in the sutured controls (n = 6; p < 0.001). A histopathological study of the rabbit corneas 1 day after laser soldering revealed sealed corneal edges with a small gap bridged by coagulated albumin. The inflammatory reaction was minimal in contrast to the sutured controls. No thermal damage was detected at the wound edges.

CONCLUSIONS

CO₂ laser soldering combined with the fiber-optic radiometer is an effective, reliable, and rapid tool for the closure of corneal wounds, and holds advantages over conventional suturing in terms of leaking pressure and surgical time.

Effect of erythropoietin on healing of corneal epithelial defects in rabbits

BACKGROUND/AIM

Corneal epithelial defects may heal slowly in patients with diabetes, limbal stem cell deficiency, extensive chemical burns or anesthetized corneas. Studies have shown that erythropoietin, a glycoprotein hormone that promotes red blood cell proliferation and inhibits apoptosis of erythroid progenitors, may also exert a cytoprotective, antiapoptotic effect on nonhematopoietic cells. The aim of the study was to examine the effect of erythropoietin on the healing process of corneal epithelial erosions in rabbit eyes.

METHODS

Fifteen New Zealand albino rabbits were divided into 3 groups following induction of unilateral uniform corneal epithelial erosions. The first group received local treatment with erythropoietin-containing cellulose-based gel 4 times daily; the second group received treatment with cellulose-based gel without erythropoietin 4 times daily, and the third group received no treatment. The healing process was monitored twice daily using cobalt-blue-filtered slit lamp photography and digital images of fluorescein-stained corneas until complete re-epithelization was achieved. Following re-epithelization, corneas were removed for histologic processing. One-way analysis of variance and Mann-Whitney tests were used for statistical analysis.

RESULTS

Mean ± SD time to complete re-epithelization was 55 ± 2.19 h in the group treated with erythropoietin-containing cellulose-based gel, 66.5 ± 14.25 h in the group treated with gel only and 62.2 ± 9.09 h in the untreated group (p = 0.16, not significant). There was no significant difference among the groups in the time to complete re-epithelization or the rate of epithelial healing. Histologic corneal evaluation revealed stromal vascularization in 2 of the 6 erythropoietin-treated rabbits and in neither of the control groups.

CONCLUSION

Erythropoietin has no beneficial effect on the rate of healing of corneal epithelial erosions in rabbit eyes, and corneal stroma neovascularization seems to be a significant adverse effect.

The effect of riboflavin-ultraviolet A-induced collagen cross-linking on intraocular pressure measurement: an experimental study

PURPOSE

To investigate the effect of corneal collagen cross-linking (CCL) on tonopen measurements of intraocular pressure (IOP).

METHODS

CCL with 0.1% riboflavin solution and 30 min of ultraviolet A radiation was performed on the right eye of 15 New Zealand albino adult rabbits (1.8-2.4 kg) (15 eyes). The left eye served as control. IOP was measured by a pressure transducer system (true IOP) and by the tonopen hand-held device (corneal applanation tonometer) before treatment, at 1 week, 1 month and 3 months following CCL. Reference pressure in the globe was increased by increments of 10 mm Hg from 10 to 40 mm Hg, using an anterior chamber infusion on a stand with variable height, and tonopen IOP measurements were recorded for each reference pressure in both eyes.

RESULTS

Before CCL, tonopen readings were similar between the two eyes (p>0.05). Tonopen underestimated the true IOP in all cases. Following CCL treatment, IOP measurements were significantly higher in the treated eye, at all time intervals (0.005<p<0.03). The most significant difference between true and measured IOP was noted at a reference pressure of 20 mm Hg.

CONCLUSIONS

IOP measurements following CCL are overestimated by the tonopen, probably due to increased stiffness of the treated cornea.

The Human Genome Project: ethical and social implications

This article explores some of the potential moral and social ramifications of the Human Genome Project. Research on the human genome is generating important ethical and social questions of at least three distinct kinds. First, what genetic information should be generated, and who should control its dissemination and use? Improved diagnostic techniques such as presymptomatic testing, carrier screening, and prenatal screening can provide information that poses significant ethical problems for individuals, employers and insurance companies, and the medical and counseling professions. Second, what genetic procedures should be employed? The burgeoning ability to manipulate human genotypes and phenotypes through procedures such as gene therapy and enzyme therapy are leading to difficult questions about which manipulations should be permitted and which should be prohibited. Third, how will this new information change lives? Increasing claims about the relationship of genetics to ethically and politically significant traits and behaviors are challenging human self-understanding and the capacity of social institutions to respond adequately.