Renato Forte

Autosomal dominant simple microphthalmos.

Congenital bilateral microphthalmos is a rare malformation of the eye, which ranges from extreme to mild reduction of total axial length. Microphthalmos may occur as an isolated ocular abnormality or as part of a systemic disorder, and different classifications of the condition have been attempted. We describe a large pedigree with 14 persons in four generations affected with bilateral microphthalmos without other ocular or systemic signs. An autosomal dominant trait with complete penetrance is proposed. Five subjects underwent a complete ophthalmological evaluation. The total axial length was measured by A scan ultrasonography in all persons. Ultrasonography showed a reduction of the total axial length (range 18.4-19.7 mm) and a reduced vitreous cavity length (range 11.4-13.5 mm) in all investigated patients. All the patients had microcornea (range 8-9.7 mm). No other ocular anomalies or associated systemic malformations were found. A review of published reports also suggests that simple, partial, posterior, pure microphthalmos and nanophthalmos are similar clinical entities sharing total axial length and vitreous cavity length reduction. Therefore, the term simple microphthalmos is proposed to identify these clinical conditions.

Does hyperbaric oxygen (HBO) delivery rescue retinal photoreceptors in retinitis pigmentosa

As previously reported in the literature, hyperbaric oxygen delivery seems to modify the natural course of retinitis pigmentosa. In order to evaluate these first encouraging data, 48 affected subjects were separately studied in two subgroups (cases and controls). All patients underwent yearly an ophthalmological examination completed by a maximum amplitude electroretinogram, conducted according to our ‘differential derivation’ system, a new recording technique specifically designed to enhance the signal-to-noise ratio. Oxygen delivery was provided regularly for 90 min daily (2.2 Absolute Atmosphere) in three cycles according to a standard protocol. In the cases, electroretinographic mean values were as follows: at TO (basal) 4.68 ± 3.81 μV; after one year (T1) 8.46 ± 5.71 μV; at two years (T2) 10.7 ± 7.6 μV; at the end of the study (T3) 14.4 ± 11.7 μV. In the controls, electroretinographic mean values were as follows: at T0 4.92 ± 3.05 μV; at T1 5.04 ± 3.07 μV; at T2 3.46 ± 2.77 μV; at T3 2.97 ± 3.61 μV. Amplitudes showed a remarkable (p<0.001) increase in the cases, while a slightly significant (p<0.02) decrease was evident at the end of the study in the controls. In our opinion, retinal oxygen availability may be critical in retinal degeneration and hyperbaric oxygen delivery, inducing hyperoxia, seems to be able to bring about the rescue of the retinal photoreceptors helping them in their metabolic requirements. Unfortunately, our study demonstrates an increase in electroretinographic responses only, which may not necessarily also mean an evident change in visual acuity.

Is acetazolamide effective in the treatment of diabetic macular edema? A pilot study

Aim: To investigate whether acetazolamide, already found to be helpful in decreasing cystoid macular edema in patients with retinitis pigmentosa, was also effective in the treatment of diabetic macular edema in nonproliferative retinopathy. Methods:Two randomized age- and sex-matched groups (cases and controls) of 12 diabetics (five Type 1 and seven Type 2) were selected for this pilot study and graded for retinopathy (Early Treatment of Diabetic Retinopathy Study – Airlie House Classification). Cases were treated with acetazolamide for three months according to a standard protocol. The Early Treatment of Diabetic Retinopathy Study chart was used for assessing far-best corrected visual-acuity, and fluorescein angiography was performed using the Heidelberg Retina Angiograph. The Amsler grid-test and computerized-perimetry (Octopus 2000R) were also performed. Results: Fluorescein-angiographic findings and perimetric data improved significantly (p < 0.01) in the acetazolamide-treated cases compared to the controls while visual-acuity varied only slightly (p > 0.01). The Amsler grid-test resulted insignificant in our study (p > 0.05). No adverse effects or significant variations in laboratory tests were recorded. Conclusion: Further clinical investigations involving larger numbers of patients and a longer follow-up are required to confirm these preliminary results. However, the present study seems to suggest that acetazolamide could be effective in reducing fluorescein-angiographic findings and improving perimetric data in diabetics with macular edema, even though the mechanism of action remains obscure. Visual-acuity varied only slightly.

Autosomal-dominant Retinitis Pigrnentosa Associated with an Arg-135-Trp Point Mutation of the Rhodopsin Gene: Clinical Features and Longitudinal Observations

Purpose: To report the clinical and functional characteristics of patients affected with autosomal-dominant transmitted retinitis pigmentosa (adRP) from a large Italian pedigree in which a point mutation predicting the Arg-135-Trp change of rhodopsin was identified by polymerase chain reaction-single-strand conformation polymorphism analysis. Methods: Seven patients, ranging in age from 6 to 41 years, underwent a full clinical ophthalmologic evaluation, kinetic visual field testing, and electroretinographic testing. Results: In agreement with previous reports, this rhodopsin mutation yielded a particularly severe phenotype, both clinically and functionally. The evaluation of patients from this pedigree in the first and second decade of life demonstrated that retinal function is still electroretinographically measurable at least until 18 years of age, although reduced to 2% to 4% of normal. Longitudinal measures showed that the rate of progression of the disease was unusually high, with an average 50% loss per year of electroretinographic amplitude and visual field area with respect to baseline. Later in the course of the disease, macular function is also severely compromised, leaving only residual central vision by the fourth decade of life. Conclusions: The phenotype associated with mutations in codon 135 of the rhodopsin molecule appears to have an unusually high progression rate and yields an extremely poor prognosis. These distinctive features make the Arg-135-Trp phenotype substantially different from the general RP population, and also from many of the other adRP pedigrees with known rhodopsin mutations reported to date. Ophthalmology 1996,-103:1443-1452

Vitreal Alterations in Retinitis pigmentosa: Biomicroscopic Appearance and Statistical Evaluation

The authors present a biomicroscopic evaluation of vitreal alterations in a large group of patients affected by primary retinitis pigmentosa (RP). 286 RP patients (571 eyes), 153 (305 eyes) males and 133 (266 eyes) females, have been studied; the mean age of this whole group was 37.26 + or - 14.93 years (age range: 5-77). Vitreal static and dynamic biomicroscopy was performed on fully dilated pupils by means of a Haag-Streit 900 slit-lamp and high-power positive precorneal lenses (+90 and +78 dpt Volk lenses). Most patients showed floating cottonball-like condensations (26.824%) often associated with fibrillary degeneration (15.88%), while non-pigmentary vitreal particulation was detected in 26.609% of cases and the pigmentary type in 12.017%, respectively. Posterior vitreal detachment was detected alone in only 0.43% of cases while 18.24% of examined eyes showed no vitreal alterations. A high statistical correlation between vitreal aspects and pigmentary grading of the fundus oculi (p = 0.0001), as well as duration of the disease (p = 0.0074), was found; at the same time, no statistical correlation with refractive error was demonstrated (p = 0.47).

Clinical heterogeneity of dominant optic atrophy: the contribution of visual function investigations to diagnosis

Abstract• Background: The variability of the visual function impairment in dominant optic atrophy (DOA) makes it difficult to diagnose the disease within genealogies. Physiologic investigations were conducted on a family with DOA to evaluate methods of detecting clinical and subclinical signs in obligate heterozygotes, in order to identify affected subjects within the genealogy and to formulate the individual and reproductive risks • Methods: Investigations included tests for color vision, contrast sensitivity function (CSF), kinetic and static computerized perimetry, transient pattern reversal visual evoked potentials (VEPs) and steady-state flash VEPs • Results: Eight subjects from the pedigree were diagnosed as having DOA. Two of them were unaware of their affection, and six showed wide clinical variability. CSF paralleled the central visual impairment, but was also slightly impaired in the two unaware subjects. Static computerized perimetry disclosed mild sensitivity defects in the central visual fields in these two patients. VEPs showed heteregeneous results as well, ranging from normal findings to severely altered tracings • Conclusions: This investigation suggests that combined clinical and functional evaluation is necessary to diagnose DOA. Particularly, the combined use of computerized perimetry, CSF, and VEPs allowed the identification of cases at a subclinical stage.

Clinical Features of Autosomal Dominant Retinitis Pigmentosa Associated with the GLY-188-ARG Mutation of the Rhodopsin Gene

Several different rhodopsin gene mutations have been identified in the last years in pedigrees with autosomal dominant retinitis pigmentosa (adRP). In view of the differences in the molecular nature and location of these mutations, defining the phenotype has become increasingly important in order to identify the clinical counterpart to the different functional abnormalities of the photopigment molecule.1–9

Scotopic Threshold Responses and Rod Intensity-Response Functions as Sensitive Indicators of the Carrier Status In X-Linked Recessive Retinitis Pigmentosa

In previous studies several authors described modifications of ERG responses in X-linked recessive retinitis pigmentosa (xLRP) carriers (1–8). Investigations on the intensity-response functions of the rod ERG also demonstrated reduction of Vmax in subjects with ophthalmoscopic evidence of the carrier status (pigmentary changes and/or tapetal-like reflex) (4). In patients affected with RP abnormalities of the Oscillatory Potentials (OPs) have also been demonstrated (9,10), suggesting a coexisting impairment of the inner retinal layers. Abnormalities of rod sensitivity were also found at the psychophysical level to flickering stimuli (11).

Central Retinal Sensitivity Repeated Measurements as Long Term Follow-Up in Retinitis Pigmentosa

In Retinitis Pigmentosa the progressive photoreceptor degeneration determines severe functional loss and visual impairment and consequently retinal sensitivity damage.

Cataractogenesis In Retinitis Pigmentosa

Retinitis Pigmentosa (RP) is a group of inherited progressive degenerative disorders of the retina genetically transmitted by recessive X-linked, recessive autosomal, dominant autosomal or digenic inheritance patterns.