Judyth C. Dawson

Maculas, monkeys, models, AMD and aging.

Age related macular degeneration (AMD) signs may be found reliably in monkeys (Macaca mulatta) bred selectively in Florida after 14 generations of inbreeding in a closed colony at the University of Puerto Rico. Progression, ultrastructure and functional losses are parallel to those found in humans.

Signs of glaucoma in rhesus monkeys from a restricted gene pool.

PurposeTo investigate the distribution of intraocular pressure (IOP) and cup properties in a colony of rhesus monkeys that has had no outside genetic input since 1938 (approximately 12 generations). This sample of sequestered monkeys is significantly larger than any previously reported. Comparisons are made with a sample of random-source monkeys to develop population estimates defining the limits of normalcy. MethodsThe IOP and cup/disc ratio estimates were collected from 701 eyes of 354 adult rhesus monkeys from the closed colony on Cayo Santiago. Puerto Rico. Results for IOP were compared with the normal rhesus IOP population distribution function calculated from an earlier sample of genetically heterogeneous rhesus. ResultsThe mean ± standard deviation IOP in the Cayo Santiago monkeys (15.8 ± 3 mmHg) related well to the calculated “normal” rhesus distribution (14.5 ± 2 mmHg) below and around the mean IOP only. Above the mean rhesus IOP, the samples from the Cayo monkeys were strongly skewed: 129 eyes had IOP more than two standard deviations above the normal mean IOP, and 54 eyes had IOP more than three standard deviations above the normal mean IOP. Cup/disc ratio estimations tended to cluster as higher values in the higher IOP quartiles. Some eyes with IOP below the mean had cup/disc ratios > 0.5. Values for IOP that were more than two standard deviations above the mean and cup/disc ratios > 0.4 were not uniformly distributed across social groupings, although incidence of high IOP was more than 25% in one group. ConclusionAfter 12 generations with the same genetic pool, expression of ocular hypertension and large optic disc cups is high but not uniform.

Repeat sample intraocular pressure variance in induced and naturally ocular hypertensive monkeys.

Purpose:To compare repeat-sample means variance of laser induced ocular hypertension (OH) in rhesus monkeys with the repeat-sample mean variance of natural OH in age-range matched monkeys of similar and dissimilar pedigrees. Materials & Methods:Multiple monocular, retrospective, intraocular pressure (IOP) measures were recorded repeatedly during a short sampling interval (SSI, 1-5 months) and a long sampling interval (LSI, 6-36 months). There were 5-13 eyes in each SSI and LSI subgroup. Each interval contained subgroups from the Florida with natural hypertension (NHT), induced hypertension (IHT1) Florida monkeys, unrelated (Strasbourg, France) induced hypertensives (IHT2), and Florida age-range matched controls (C). Repeat-sample individual variance means and related IOPs were analyzed by a parametric analysis of variance (ANOV) and results compared to non-parametric Kruskal-Wallis ANOV. Results:As designed, all group intraocular pressure distributions were significantly different (P ≤ 0.009) except for the two (Florida/Strasbourg) induced OH groups. A parametric 2 × 4 design ANOV for mean variance showed large significant effects due to treatment group and sampling interval. Similar results were produced by the nonparametric ANOV. Induced OH sample variance (LSI) was 43× the natural OH sample variance-mean. The same relationship for the SSI was 12×. Conclusion:Laser induced ocular hypertension in rhesus monkeys produces large IOP repeat-sample variance mean results compared to controls and natural OH.