Influence of Axial Length on Intraocular Pressure Measurement With Three Tonometers in Childhood Glaucoma

PURPOSE

To determine the agreement between intraocular pressure (IOP) measurements obtained using the handheld version of the Goldmann applanation (Perkins; Clement-Clarke, Haag-Streit, Harlow, United Kingdom), rebound Icare-Pro (Icare, Tiolat Oy, Helsinki, Finland), and Tonopen XL (Reichert Inc., Depew, NY) tonometers in children with childhood glaucoma and to identify factors that may affect those measurements.

METHODS

Ninety-one eyes of 46 children with early-onset childhood glaucoma were included in this cross-sectional study in which IOP, ocular axial length, anterior chamber depth, lens thickness, vitreous length, and central corneal thickness measurements were obtained under general anesthesia. Agreement between tonometers was evaluated using intraclass correlation coefficients (ICCs) and the Bland-Altman method. The influence of ocular biometric parameters and central corneal thickness on IOP measurements was analyzed using multiple linear regression analysis.

RESULTS

The mean age of the children in the current study was 29.1 months (range: 13 to 31 months). The Icare-Pro and Tonopen XL overestimated IOP measurements compared to the Perkins tonometer (Icare-Pro-Perkins mean IOP difference: 2.2 ± 3.4 mm Hg, P < .0001, 95% confidence interval [CI]: 1.5 to 2.9 vs Tonopen XL-Perkins mean IOP difference: 6.7 ± 7.1 mm Hg, P < .0001, 95% CI: 5.2 to 8.2). The Icare-Pro showed greater agreement with the Perkins tonometer than the Tonopen XL (ICC: 0.789, 95% CI: 0.697 to 0.856, P < .0001 vs 0.453, 95% CI: 0.272 to 0.603, P < .0001). Ocular axial length affected IOP measurements the most, finding increased impact on Tonopen XL (slope: 0.086, 95% CI: 0.013 to 0.16, P = .022 vs 0.997, 95% CI: 0.369 to 1.625, P = .002 vs 1.571, 95% CI: 0.541 to 2.602, P < .0001 for Perkins, Icare-Pro, and Tonopen XL IOP measurements, respectively).

CONCLUSIONS

Ocular axial length affects IOP measured by the Perkins, Icare-Pro, and Tonopen XL devices in patients with childhood glaucoma. The Icare-Pro shows more agreement with the Perkins tonometer than the Tonopen XL; therefore, it seems to be a more suitable option for these patients. [J Pediatr Ophthalmol Strabismus. 2020;57(1):27-32.].

Longitudinal reproducibility of spectral domain optical coherence tomography in children with physiologic cupping and stable glaucoma

PURPOSE

To determine whether Spectralis (Heidelberg, Germany) spectral domain optical coherence tomography (SD-OCT) measurements are reproducible over time in children with physiologic cupping and stable glaucoma.

METHODS

Subjects were identified from a subset of participants in an earlier retrospective study conducted by our group and included children (<18 years of age) with physiologic cupping and stable primary congenital glaucoma (PCG) having had at least 2 SD-OCTs over a period of more than 1 between April 2010 and September 2015. Thicknesses of average peripapillary retinal nerve fiber layer (pRNFL) and six individual sectors and volumes of three segmented retinal layers and total retina were measured. Spectralis review software was used for segmentation. Intraclass correlation coefficients (ICC) and coefficient of variation (COV) were calculated.

RESULTS

A total of 35 eyes of 35 children were included: 15 eyes had physiologic cupping; 20 eyes, PCG. Mean ages at initial SD-OCT were 11.2 ± 3.3 years and 9.7 ± 3.3, respectively; mean intervals between first and last imaging were 2.2 ± 1.1 and 3.0 ± 1.4 years, respectively. ICCs across three visits for both groups for average and sectoral pRNFL thicknesses were 0.887-0.997 and for segmented retinal volumes were 0.806-0.993. ICCs for total retinal volume for physiologic cupping and PCG were 0.993 and 0.954, respectively. COVs for average pRNFL thickness were 0.9% and 1.7%, respectively. For all other measurements, COVs ranged from 0.3% to 5.4%.

CONCLUSIONS

Reproducibility of longitudinal SD-OCT measurements for average pRNFL thickness in children with stable glaucoma over about 2 years is comparable to short-term reproducibility (COV) in normal children (1.16%) and normal and glaucoma adults (1.62%-3.4%).

Congenital Glaucoma Associated with An Arginase Deficit: A Case Report

PURPOSE

Argininemia is a rare congenital disease caused by deficiency. We present here a case in which argininemia and buphthalmos are associated.

CASE REPORT

This female patient, who died at eighteen, had intraocular pressure correlated with her blood levels or arginine. Hyperammoniemia causes a change in pH that could explain an increase in aqueous humor (from the ciliary body). Ammonium ions could also damage the matrix of the trabecular meshwork.

CONCLUSIONS

The association of argininemia and buphthalmos have never been described. This might be because of the different expressions of the disease, or because nobody has ever looked for ocular hypertension in these patients unless they had subjective symptoms.

Randomized Trial on Illuminated-Microcatheter Circumferential Trabeculotomy Versus Conventional Trabeculotomy in Congenital Glaucoma

PURPOSE

To compare 1-year outcomes of illuminated microcatheter-assisted circumferential trabeculotomy (IMCT) vs conventional partial trabeculotomy (CPT) for primary congenital glaucoma (PCG).

DESIGN

Randomized clinical trial.

METHODS

Forty eyes of 31 patients with unilateral or bilateral primary congenital glaucoma aged less than 2 years were randomized to undergo IMCT (20 eyes) or CPT (20 eyes). Primary outcome measure was intraocular pressure (IOP) reduction. The success criterion was defined as IOP ≤ 12 mm Hg without and with antiglaucoma medications (absolute success and qualified success, respectively).

RESULTS

The mean age of our study population was 8.35 ± 1.2 months. The mean preoperative IOP was 24.70 ± 3.90 mm Hg in the IMCT group and 24.60 ± 3.31 mm Hg in the CPT group. Both groups were comparable with respect to preoperative IOP, corneal clarity, corneal diameter, vertical cup-to-disc ratio, and refractive error. In the IMCT group, 360-degree cannulation was achieved in 80% (16/20) of eyes. For the IMCT group and CPT groups, respectively, the absolute success rates were 80% (16/20) and 60% (12/20) (P < .001) and qualified success rates were 90% (18/20) and 70% (14/20) (P < .001). Both procedures produced a statistically significant reduction in IOP, and eyes undergoing IMCT achieved a lower IOP than CPT group eyes at 12 months follow-up (9.5 ± 2.4 mm Hg and 11.7 ± 2.1 mm Hg, respectively, P < .001).

CONCLUSION

In primary congential glaucoma, illuminated microcatheter-assisted 360-degree circumferential trabeculotomy performed better than conventional partial trabeculotomy at 1 year follow-up and resulted in significantly lower IOP measurements.

Primary Congenital Glaucoma Versus Glaucoma Following Congenital Cataract Surgery: Comparative Clinical Features and Long-term Outcomes

PURPOSE

To report and compare visual and glaucoma outcomes in primary congenital glaucoma (PCG) vs glaucoma following congenital cataract surgery (GFCS).

DESIGN

Retrospective, observational, comparative case series.

METHODS

Setting: Emory Eye Center, Atlanta, Georgia.

STUDY POPULATION

Pediatric glaucoma patients (age 0-18 years) treated at Emory by 1 clinician with ≥2-year follow-up. Glaucoma was defined according to the 9th Consensus Report of the World Glaucoma Association.

MAIN OUTCOME MEASURES

Snellen-equivalent logMAR visual acuity (VA) and glaucoma control (IOP ≤21, no devastating complications, no recommendation for further glaucoma surgery). Asymptotic Wilcoxon-Mann-Whitney rank sum tests were employed to compare glaucoma subgroups.

RESULTS

Included were 72 PCG and 56 GFCS cases, with mean follow-up time of 7.4 ± 4.1 and 8.0 ± 3.8 years, respectively. At last follow-up, PCG showed better median VA than GFCS in worse-seeing eyes (20/60 [interquartile range (IQR) 20/30-20/200] vs 20/400 [IQR 20/70-hand motion], respectively, P < .0001) and in better-seeing eyes of bilaterally-affected children (20/30 [IQR 20/20-20/60] vs 20/70 [IQR 20/35-20/100], respectively, P = .024).The following variables characterized the PCG and GFCS groups' glaucoma status, respectively: mean age at diagnosis (years), 0.70 ± 1.3 vs 3.3 ± 3.5 (P < .0001); median IOP (mm Hg), 15.50 [IQR 12.1-19.4] vs 17.50 [IQR 14.9-22], P = .037; median number of glaucoma medications at last follow-up, 1.49 [IQR 0-2] vs 2.54 [IQR 1-4], P < .0001; median number of glaucoma surgeries, 1.0 [IQR 1-2] vs 1.25 [IQR 0.5-2.0], P = .09.

CONCLUSIONS

Children with PCG (vs those with GFCS) presented earlier, had better vision, required fewer medications to control disease, and had lower IOP at last follow-up.

Characteristics of Children With Primary Congenital Glaucoma Receiving Trabeculotomy and Goniotomy

PURPOSE

To describe the groups of patients who received trabeculotomy or goniotomy for the treatment of primary congenital glaucoma (PCG) regarding age at treatment, intraocular pressure (IOP) outcome, and medication burden.

METHODS

A retrospective chart review of patients with PCG seen at Rutgers New Jersey Medical School, Newark, New Jersey, from 1998 to 2012 was conducted. Inclusion criteria were patients who received trabeculotomy or goniotomy with at least 9 months of follow-up. Presenting examination, surgical intervention, IOP, and number of medications at 1 and 2 years postoperatively were recorded. Absolute and qualified success, defined as IOP greater than 5 and less than 21 mm Hg without and with medications, respectively, was determined.

RESULTS

Fifty eyes of 29 patients were diagnosed as having PCG. Of those, 25 eyes received trabeculotomy or goniotomy, with 19 fulfilling inclusion criteria. Average age at the time of trabeculotomy was 8 months versus 21 months for patients undergoing goniotomy. Mean IOP was significantly reduced (P < .001) for both trabeculotomy and goniotomy by 29.5% at 1 year and 33.3% at 2 years. There was no significant difference in IOP control between trabeculotomy and goniotomy groups. Patients in the goniotomy group were treated with significantly more medications before and after surgery compared to patients receiving trabeculotomy (P < .01), resulting in a greater rate of absolute success in trabeculotomy at 1 and 2 years.

CONCLUSIONS

Patients with PCG who underwent trabeculotomy had higher IOP and were treated at an earlier age than those who had goniotomy. Both effectively lowered IOP up to 2 years with greater medication burden in patients receiving goniotomy.

Surgical and Visual Outcomes of Childhood Glaucoma at a Tertiary Eye Care Center in South India

PURPOSE

This study aimed to categorize patients with childhood glaucoma into groups, study the clinical characteristics of the eyes affected, and determine the outcomes after surgery.

DESIGN

This was a retrospective, consecutive, nonrandomized study.

METHODS

Patients with childhood glaucoma who underwent planned primary trabeculectomy or combined trabeculotomy-trabeculectomy (CTT) between January 2003 and December 2008 were enrolled. Main outcome measures were intraocular pressure (IOP), visual acuity, corneal clarity, and any surgical and anesthetic complications.

RESULTS

One hundred thirty-one eyes of 81 patients were included. They were 61.7% male. Mean patient age was 6.1 ± 4.1 years, and the mean age at surgery was 35.8 ± 40.9 months. Postoperatively, the improvement in visual acuity was highly statistically significant at all follow-ups (P < 0.001). The IOP values showed a significant reduction from 29.2 ± 9.7 mm Hg preoperatively to 13.7 ± 5.3 mm Hg (P < 0.001) at 6-month follow-up and 12.1 ± 2.2 mm Hg at last follow-up. Cumulative corneal clarity improved significantly postoperatively (P < 0.001). A comparison of trabeculectomy alone and CTT showed that both procedures were quite effective. At 1 year, overall complete success was seen in 73.3%, qualified success in 16.8%, and failure in 10.7%.

CONCLUSIONS

This study suggests that CTT is safe and effective in both primary and secondary childhood glaucomas. Trabeculectomy alone is also highly effective in certain cases, and proper case selection is essential to attain optimum results. Surgical intervention leads to improvement in vision and corneal clarity and also achieves long-term IOP control.

Primary congenital glaucoma outcomes: lessons from 23 years of follow-up

PURPOSE

To determine in primary congenital glaucoma whether age of presentation influences surgical success, the degrees of angle surgery needed to achieve glaucoma control, and whether there are critical ages where glaucoma progresses, requiring further surgical management.

DESIGN

Retrospective cohort study.

METHODS

The medical records of patients with primary congenital glaucoma over a 23-year period were reviewed: 192 procedures were performed on 117 eyes (70 patients). The number and age of angle procedures and final visual acuity was analyzed. Surgical success was defined as stable intraocular pressure and optic disc appearance.

RESULTS

Procedures involving 83 of the 110 eyes (75.5%) undergoing angle surgery were successful, with 2-, 4-, 6-, and 10-year success rates of 92%, 86%, 84%, and 75%, respectively. Subgroup analysis (<3 months; 3-6 months; >6 months) comparing age of diagnosis to visual outcome (<20/200, 20/200-20/40, >20/40) was significant (P = .04). The age at first operation (P = .94), the number of angle operations (P = .43), and their effect on angle surgery success was not significant. Seven of 192 operations were performed after the age of 8 years (3.6%). After the initial angle surgeries within the first year of life, the third procedure occurred at a median age of 2.4 years (interquartile ratio [IQR] 0.6-3.8 years) and the fourth procedure occurred at a median age of 5.3 years (IQR 2.5-6.1 years).

CONCLUSIONS

Children diagnosed at <3 months of age had a visual outcome of <20/200 despite successful glaucoma control. Age of presentation did not affect surgical success. A total of 78.9% of cases undergoing primary trabeculotomy were controlled with 1 operation: 4 clock hours of angle (120 degrees). Analysis of glaucoma progression suggests critical ages where further glaucoma surgery is required at around 2 and 5 years of age.

Biomechanical profile of the cornea in primary congenital glaucoma

PURPOSE

The aim of our study was to investigate the biomechanical properties of the cornea in primary congenital glaucoma (PCG) and to identify the potential ocular determinants, which affect the corneal biomechanical metrics.

METHODS

Corneal hysteresis (CH), corneal resistance factor (CRF) and central corneal thickness (CCT) were measured in 26 patients with PCG (40 eyes) with the aid of ocular response analyser. In vivo laser-scanning confocal microscopy was used for the estimation of stromal keratocyte density (KD) and the evaluation of corneal endothelium. Twenty normal subjects (40 eyes) served as controls. Student's t-test and Pearson's correlation coefficients were used for statistical analysis. p Values <0.05 were considered statistically significant.

RESULTS

Corneal hysteresis, CRF and CCT were significantly reduced in patients with PCG (all p < 0.05). Corneal hysteresis and CRF negatively correlated with the corneal diameter in both groups (r(1) = -0.53, r(2) = -0.66, p < 0.001 for CH and r(1) = -0.61, r(2) = -0.69, p < 0.001 for CRF). Moreover, we identified a significant correlation between CH and CRF with CCT in both groups (r(1) = 0.51, r(2) = 0.48, p < 0.001 for CH and r(1)  = 0.45, r(2) = 0.44, p < 0.001 for CRF). Mean KD was significantly reduced both in the anterior and posterior corneal stroma in patients with PCG (764 ± 162 and 362 ± 112 cells/mm(2) , respectively) compared with controls (979 ± 208 and 581 ± 131 cells/mm(2) , respectively) (p < 0.001). There was no significant correlation between the keratocyte density in anterior and/or posterior stroma and CH or CRF in any group (r(1) = 0.29, r(2) = 0.31, p < 0.06). Mean endothelial cell density was also significantly reduced in PCG group (2920 ± 443 cells/mm(2) ) compared with control group (3421 ± 360 cells/mm(2) ) (p < 0.001). Pleomorphism and polymegalism were significantly increased in corneal endothelium of patients with PCG.

CONCLUSIONS

  Our results showed a significant reduction in CH and CRF in PCG. Both CH and CRF were negatively correlated with corneal diameter. A significant correlation of CH and CRF with CCT was identified in both groups. Keratocyte density was decreased in PCG, but did not have a significant impact on CH and CRF. Mean endothelial density was also decreased in PCG. Our results suggest that reduced CCT and increased corneal diameter are major ocular determinants for the modified corneal biomechanical profile in PCG, while cellular alterations in corneal stroma and endothelium have no significant biomechanical impact.

Medical and surgical outcomes in childhood glaucoma: a population-based study

INTRODUCTION

To describe the clinical and surgical outcomes among patients younger than 20 years of age diagnosed with glaucoma in a defined population during a 40-year period.

METHODS

The medical records of all patients (<20 years) diagnosed with glaucoma in Olmsted County, Minnesota, from January 1, 1965, through December 31, 2004, were retrospectively reviewed.

RESULTS

Thirty children (45 eyes) were diagnosed with various forms of glaucoma during the 40-year study period. During a mean follow-up of 12.5 years (range, 7 days to 32 years), 18 (60%) of the 30 children underwent a mean of 2.7 surgeries (range, 1 to 10), including 6 (20%) patients whose sole surgery consisted of enucleation or evisceration for a blind, painful eye. Twenty-eight (93%) of the 30 children required medical management during the follow-up period, including 14 (47%) treated before their first surgery. At the final follow-up examination, 11 (37%) had a visual acuity of 20/200 or worse. The 10-year Kaplan-Meier risk of vision decreasing less than 20/200 in all glaucoma patients was 22.7% (95% CI, 0-40.9), and patients requiring any glaucoma surgery was 68.3% (95% CI, 42.4-82.6).

CONCLUSIONS

In this population-based study of children diagnosed with glaucoma during a 40-year period, most patients required surgery, with few being successfully controlled by medications alone. A poor visual outcome or the loss of an eye was relatively common.

Long-term results of surgery in childhood glaucoma

PURPOSE

The aim of this study is to assess the functional results and morphological parameters in children surgically treated for glaucoma.

METHODS

Data from 43 patients and 68 eyes who were operated in our department between 1990 and 2002 were collected. This retrospective trial included primary congenital glaucoma (n=36), and secondary glaucoma (n=7) in Rieger-Axenfeld syndrome and Sturge Weber syndrome. Intraocular pressure (IOP), axial length of the eyeball, visual acuity, refractive errors and orthoptic status were analysed.

RESULTS

The age of patients at the first surgery was 6.0 +/- 5.3 months (range 0.7 to 28.0 months). The mean period of follow-up was 57.3 +/- 36.8 months (6.0-161.0). The mean number of surgical procedures performed on one eye was 2.5 +/- 2.4 procedures (1-11). The mean IOP before the first surgery was 31.0 +/- 7.9 mmHg (17.5-52.0), and was 15.0 +/- 3.9 mmHg (7.0-28.0) at the last visit. 49 eyes (72.1%) did not need any further medical treatment after the last surgical procedure. The IOP was 18 mmHg or lower without medication in 29 eyes (42.6%) after just one surgical procedure (21 trabeculotomy, 8 combined trabeculotomy/trabeculectomy with or without mitomycin-C). At the first examination, the mean axial length of the eyeball was 22.6 +/- 1.8 mm (the mean normal value at this age is 20.3 +/- 0.7 mm), and was 24.4 +/- 2.0 mm at the last visit (the mean normal value at this age is 22.2 +/- 0.6 mm). The best corrected visual acuity at the last visit was 0.25 +/- 4.6 lines; the normal range of visual acuity at this age is from 0.4 +/- 4.0 lines to 0.8 +/- 3.0 lines. Visual acuity was 0.32 or more in 53.0% of the eyes. Visual acuity was lower than 0.1 in only 15.2% of the eyes. Myopia was present in 57.4% of the eyes with a mean spherical equivalent of -6.1 +/-3.9 dioptres. 15 patients (34.9%) developed strabismus. 22 patients (51.2%) were treated with part-time occlusion. Binocular function as assessed with the Lang-1 test was positive in 17 of 30 patients (56.7%).

CONCLUSIONS

Although a good long-term IOP-control can often be achieved in childhood glaucoma, the visual acuity remains below the normal range in most cases despite close orthoptic follow-up.

Regeneration of retinal ganglion cell axons in organ culture is increased in rats with hereditary buphthalmos

This study used organ cultures to examine whether retinal ganglion cells (RGCs) retain their ability to regenerate axons in buphthalmos. A rat mutant with hereditary buphthalmos was used to (1) determine whether the extent of RGC loss corresponds to the severity and duration of elevated intraocular pressure (IOP), (2) examine whether RGCs exposed to an elevated IOP are able to regenerate their axons in a retina culture model, and (3) analyze the proteome of the regenerating retina in order to identify putative regeneration-associated proteins. Retrograde labeling of RGCs revealed a decrease in their numbers in the retinas of buphthalmic eyes that increased with age. Quantification of axons growing out of retinal explants taken at different stages of the disease demonstrated that buphthalmic RGCs possess a remarkable potential to regrow axons. As expected, immunohistochemistry and immunoblotting revealed that elevated IOP was associated with upregulation of certain known proteins, such as growth-associated protein 43, glial fibrillary acidic protein, and endothelin-1. In addition, two-dimensional polyacrylamide gel electrophoresis and mass spectrometry revealed several spots corresponding to proteins that were specifically regulated when buphthalmic RGCs were permitted to regrow their axons. Out of the proteins identified, heat-shock protein (HSP)-60 was constantly expressed during axonal growth at all stages of the disease. Antibodies against HSP-60 reduced axonal growth, indicating the involvement of this protein in regenerative axonal growth. These data are the first to show that diseased retinal neurons can grow their axons, and that HSP-60 supports neuritogenesis. This model may help to elucidate the fundamental mechanisms of optic neuropathy at stages preceding death caused by chronic injury, and aid in the development of neuroprotective strategies.

[Eye growth in children with primary congenital glaucoma after trabeculectomy]

PURPOSE

Evaluation of the influence of intraocular pressure (IOP) after trabeculectomy on the axial length and refraction of eyeballs in children with primary congenital glaucoma.

MATERIAL AND METHODS

Thirty six eyes of 23 children at the age from 7 days to 6.5 years (mean 17.1 months), were examined. Measurements of corneal diameter, axial length, IOP and refraction were done before trabeculectomy and in the long-term follow-up (mean 7.9 years) after surgery.

RESULTS

Horizontal corneal diameter didn't change and ranged from 10 to 15 mm, mean 13.22 mm. Mean value of axial length before trabeculectomy was 22.45 mm and 23.27 mm at last visit. The difference was statistically significant. The axis decreased in 3 eyes, was the same in 3 eyes. In the others the eye growth changed proportionally to the age of child. IOP values were statistically lower after surgery (mean 16 mmHg) than before treatment (mean 35.51 mmHg). There was no correlation between IOP and axial length of eyeballs (p = 0.69) and between IOP and refraction changes (p = 0.42) in the long-term follow-up.

CONCLUSIONS

There is small influence of normalised IOP after trabeculectomy on size of eyeballs and refraction in children with primary congenital glaucoma. The development of eyeballs even buphthalmic is proportionally to the age.

Fibrinogen concentration in the aqueous humor of buphthalmic rabbits

Fibrinogen concentration in the aqueous humor of buphthalmic rabbits, AXBU/J, and those of the normal parent strain AX/J are 0.36 +/- 0.14 and 0.08 +/- 0.01 mg/ml, respectively. There was no detectable fibrinogen in the aqueous humor of normal inbred strain III/J rabbits. Among the buphthalmic rabbits, elevated fibrinogen concentration in the aqueous humor was observed in two month old prodromal rabbits, indicating a small leakage of fibrinogen into the anterior chamber before the development of buphthalmia. Protein concentration in the aqueous humor was close to normal, in spite of an elevated level of fibrinogen in the young buphthalmic rabbits. Severe protein leakage was seen in only some of the old buphthalmic rabbits.

Infantile glaucoma: electrophysiology

Thirty-eight children with congenital infantile glaucoma (hydrophthalmia) were examined using electrophysiological methods. In contrast with adult glaucoma, hydrophthalmia is characterized by early changes in the electro-retinogram and rise of the threshold of electrical phosphene, which points to serious pathological changes in the retinal optic nerve. In such cases surgical intervention is indicated.

[In vivo-measurements of the latitude of Schlemm's canal in buphthalmos (author's transl]

In 9 cases of buphthalmos 'in vivo-measurements of the latitude of Schlemm's canal gave us a mean value of 678 micron. The extreme values ranged between 600 micron and 800 micron. Therefore these values differ significantly from those measured 'in vivo' in chronic simple glaucoma (x:542 micron, extreme values 425 micron and 625 micron). The latitude of Schlemm's canal correlates with the diameter of cornea and the rise of intra-oculare pressure. In cases of buphtha-mos the success of trabeculotomy seems to be better, if the latitude of Schlemm's canal is less than l50 micron. Trabeculotomy should therefore be performed as soon as possible.

Correlation of aqueous humor ascorbate with intraocular pressure and outflow facility in hereditary buphthalmic rabbits

The hypotensive effect of ascorbate on intraocular pressure has been reported following topical application, oral administration, or anterior chamber infusion in animals. The present report describes the correlation of aqueous humor ascorbate concentration with intraocular pressure as well as outflow facility in vivo. Low aqueous ascorbate level was seen in buphthalmic eyes with high intraocular pressure and low outflow facility. The opposite correlation was observed in normal eyes. Ascorbate concentration in the anterior chamber of the rabbit eye is apparently related to the alteration of outflow facility and the movement of fluid in the anterior chamber.

[Hydrophthalmia and configuration of the optic disc (author's transl)]

Three sisters, one brother, and the father of a female patient with primary hydrophthalmus on both eyes had abnormally great physiologic cups. The cup/disc ratio was between 0.5 and 0.72. Two other brothers showed a cup/disc ratio between 0.37 and 0.42, whereas the mother had a cup/disc ratio of 0.2 on both sides. The enlarged physiologic cups of the sisters, the brother, and the father of the propositus correspond to the 4th category of the classification according to Elschnig. Like the hydrophthalmus as a result of a functional disturbance of the eye cup, the occurrence of abnormally big physiologic cups is also referred to the organizing and forming effects of the eye cup. Whether there exists an intrafamiliar relationship between the hydrophthalmus and the abnormally big physiologic cups or not is to be elucidated by further investigations.